diff --git a/src/libsystemd-network/arp-util.c b/src/libsystemd-network/arp-util.c
index ad61614f12..a017cb7ab2 100644
--- a/src/libsystemd-network/arp-util.c
+++ b/src/libsystemd-network/arp-util.c
@@ -3,7 +3,6 @@
   Copyright © 2014 Axis Communications AB. All rights reserved.
 ***/
 
-#include <arpa/inet.h>
 #include <linux/filter.h>
 #include <netinet/if_ether.h>
 
@@ -11,6 +10,7 @@
 #include "ether-addr-util.h"
 #include "fd-util.h"
 #include "in-addr-util.h"
+#include "socket-util.h"
 #include "unaligned.h"
 
 int arp_update_filter(int fd, const struct in_addr *a, const struct ether_addr *mac) {
diff --git a/src/libsystemd-network/arp-util.h b/src/libsystemd-network/arp-util.h
index b66a81bf9b..4152c3a098 100644
--- a/src/libsystemd-network/arp-util.h
+++ b/src/libsystemd-network/arp-util.h
@@ -5,11 +5,7 @@
   Copyright © 2014 Axis Communications AB. All rights reserved.
 ***/
 
-#include <net/ethernet.h>
-#include <netinet/in.h>
-
-#include "socket-util.h"
-#include "sparse-endian.h"
+#include "forward.h"
 
 int arp_update_filter(int fd, const struct in_addr *a, const struct ether_addr *mac);
 int arp_network_bind_raw_socket(int ifindex, const struct in_addr *a, const struct ether_addr *mac);
diff --git a/src/libsystemd-network/dhcp-client-id-internal.h b/src/libsystemd-network/dhcp-client-id-internal.h
index 382575e7a2..f43d278cdd 100644
--- a/src/libsystemd-network/dhcp-client-id-internal.h
+++ b/src/libsystemd-network/dhcp-client-id-internal.h
@@ -1,12 +1,12 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
+#include <linux/if_ether.h>
+
 #include "sd-dhcp-client-id.h"
-#include "sd-json.h"
 
 #include "dhcp-duid-internal.h"
-#include "macro.h"
-#include "siphash24.h"
+#include "forward.h"
 #include "sparse-endian.h"
 
 /* RFC 2132 section 9.14: its minimum length is 2.
diff --git a/src/libsystemd-network/dhcp-client-internal.h b/src/libsystemd-network/dhcp-client-internal.h
index 247fd9d912..3248e1098b 100644
--- a/src/libsystemd-network/dhcp-client-internal.h
+++ b/src/libsystemd-network/dhcp-client-internal.h
@@ -1,11 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <errno.h>
-
 #include "sd-dhcp-client.h"
 
-#include "macro.h"
+#include "forward.h"
 #include "network-common.h"
 
 typedef enum DHCPState {
diff --git a/src/libsystemd-network/dhcp-duid-internal.h b/src/libsystemd-network/dhcp-duid-internal.h
index 0d3d6b5cef..061786cd02 100644
--- a/src/libsystemd-network/dhcp-duid-internal.h
+++ b/src/libsystemd-network/dhcp-duid-internal.h
@@ -1,12 +1,11 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "sd-device.h"
 #include "sd-dhcp-duid.h"
 #include "sd-id128.h"
 
 #include "ether-addr-util.h"
-#include "macro.h"
+#include "forward.h"
 #include "sparse-endian.h"
 
 #define SYSTEMD_PEN    43793
diff --git a/src/libsystemd-network/dhcp-lease-internal.h b/src/libsystemd-network/dhcp-lease-internal.h
index 394c71bdf0..0ed8c3fc93 100644
--- a/src/libsystemd-network/dhcp-lease-internal.h
+++ b/src/libsystemd-network/dhcp-lease-internal.h
@@ -5,13 +5,12 @@
   Copyright © 2013 Intel Corporation. All rights reserved.
 ***/
 
-#include "sd-dhcp-client.h"
+#include "sd-dhcp-lease.h"
 
-#include "alloc-util.h"
 #include "dhcp-client-id-internal.h"
 #include "dhcp-option.h"
+#include "forward.h"
 #include "list.h"
-#include "time-util.h"
 
 struct sd_dhcp_route {
         struct in_addr dst_addr;
diff --git a/src/libsystemd-network/dhcp-network.c b/src/libsystemd-network/dhcp-network.c
index 207f68a5e6..24b8c12011 100644
--- a/src/libsystemd-network/dhcp-network.c
+++ b/src/libsystemd-network/dhcp-network.c
@@ -3,20 +3,18 @@
   Copyright © 2013 Intel Corporation. All rights reserved.
 ***/
 
-#include <errno.h>
 #include <linux/filter.h>
 #include <linux/if_infiniband.h>
 #include <linux/if_packet.h>
-#include <net/ethernet.h>
-#include <net/if.h>
 #include <net/if_arp.h>
 #include <stdio.h>
 #include <string.h>
 
 #include "dhcp-network.h"
 #include "dhcp-protocol.h"
+#include "ether-addr-util.h"
 #include "fd-util.h"
-#include "log.h"
+#include "socket-util.h"
 #include "unaligned.h"
 
 static int _bind_raw_socket(
diff --git a/src/libsystemd-network/dhcp-network.h b/src/libsystemd-network/dhcp-network.h
index eb9dab4453..c493cfeee5 100644
--- a/src/libsystemd-network/dhcp-network.h
+++ b/src/libsystemd-network/dhcp-network.h
@@ -1,11 +1,8 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
-#include <stdint.h>
-
-#include "ether-addr-util.h"
-#include "socket-util.h"
+#include "forward.h"
+#include "sparse-endian.h"
 
 int dhcp_network_bind_raw_socket(
                 int ifindex,
diff --git a/src/libsystemd-network/dhcp-option.c b/src/libsystemd-network/dhcp-option.c
index 4945acfd56..a840b61462 100644
--- a/src/libsystemd-network/dhcp-option.c
+++ b/src/libsystemd-network/dhcp-option.c
@@ -3,8 +3,6 @@
   Copyright © 2013 Intel Corporation. All rights reserved.
 ***/
 
-#include <errno.h>
-#include <stdint.h>
 #include <stdio.h>
 
 #include "alloc-util.h"
@@ -14,6 +12,7 @@
 #include "hostname-util.h"
 #include "memory-util.h"
 #include "ordered-set.h"
+#include "string-util.h"
 #include "strv.h"
 #include "utf8.h"
 
diff --git a/src/libsystemd-network/dhcp-option.h b/src/libsystemd-network/dhcp-option.h
index 289e833443..c3738b87c1 100644
--- a/src/libsystemd-network/dhcp-option.h
+++ b/src/libsystemd-network/dhcp-option.h
@@ -1,12 +1,10 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdint.h>
-
-#include "sd-dhcp-option.h"
+#include "sd-dhcp-option.h" /* IWYU pragma: export */
 
 #include "dhcp-protocol.h"
-#include "dns-resolver-internal.h"
+#include "forward.h"
 #include "hash-funcs.h"
 
 struct sd_dhcp_option {
diff --git a/src/libsystemd-network/dhcp-packet.c b/src/libsystemd-network/dhcp-packet.c
index 6dcfe80672..46317c997c 100644
--- a/src/libsystemd-network/dhcp-packet.c
+++ b/src/libsystemd-network/dhcp-packet.c
@@ -3,8 +3,6 @@
   Copyright © 2013 Intel Corporation. All rights reserved.
 ***/
 
-#include <errno.h>
-#include <net/ethernet.h>
 #include <net/if_arp.h>
 #include <string.h>
 
diff --git a/src/libsystemd-network/dhcp-packet.h b/src/libsystemd-network/dhcp-packet.h
index 751321b92f..a7f2e12b4f 100644
--- a/src/libsystemd-network/dhcp-packet.h
+++ b/src/libsystemd-network/dhcp-packet.h
@@ -1,10 +1,8 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
-#include <stdint.h>
-
 #include "dhcp-protocol.h"
+#include "forward.h"
 
 int dhcp_message_init(
                 DHCPMessage *message,
diff --git a/src/libsystemd-network/dhcp-protocol.h b/src/libsystemd-network/dhcp-protocol.h
index b3b247a567..ca872a8081 100644
--- a/src/libsystemd-network/dhcp-protocol.h
+++ b/src/libsystemd-network/dhcp-protocol.h
@@ -7,11 +7,10 @@
 
 #include <netinet/ip.h>
 #include <netinet/udp.h>
-#include <stdint.h>
 
 #include "sd-dhcp-protocol.h"
 
-#include "macro.h"
+#include "forward.h"
 #include "sparse-endian.h"
 #include "time-util.h"
 
diff --git a/src/libsystemd-network/dhcp-server-internal.h b/src/libsystemd-network/dhcp-server-internal.h
index 0b2fa96524..1da18cce60 100644
--- a/src/libsystemd-network/dhcp-server-internal.h
+++ b/src/libsystemd-network/dhcp-server-internal.h
@@ -5,14 +5,14 @@
   Copyright © 2013 Intel Corporation. All rights reserved.
 ***/
 
+#include "sd-dhcp-lease.h"
 #include "sd-dhcp-server.h"
-#include "sd-event.h"
 
 #include "dhcp-client-id-internal.h"
 #include "dhcp-option.h"
+#include "forward.h"
 #include "network-common.h"
-#include "ordered-set.h"
-#include "time-util.h"
+#include "sparse-endian.h"
 
 typedef enum DHCPRawOption {
         DHCP_RAW_OPTION_DATA_UINT8,
@@ -25,7 +25,7 @@ typedef enum DHCPRawOption {
         _DHCP_RAW_OPTION_DATA_INVALID,
 } DHCPRawOption;
 
-struct sd_dhcp_server {
+typedef struct sd_dhcp_server {
         unsigned n_ref;
 
         sd_event *event;
@@ -78,7 +78,7 @@ struct sd_dhcp_server {
 
         int lease_dir_fd;
         char *lease_file;
-};
+} sd_dhcp_server;
 
 typedef struct DHCPRequest {
         /* received message */
diff --git a/src/libsystemd-network/dhcp-server-lease-internal.h b/src/libsystemd-network/dhcp-server-lease-internal.h
index f206e0118f..4a36df6ead 100644
--- a/src/libsystemd-network/dhcp-server-lease-internal.h
+++ b/src/libsystemd-network/dhcp-server-lease-internal.h
@@ -2,11 +2,10 @@
 #pragma once
 
 #include "sd-dhcp-server-lease.h"
-#include "sd-json.h"
 
 #include "dhcp-client-id-internal.h"
 #include "dhcp-server-internal.h"
-#include "time-util.h"
+#include "forward.h"
 
 typedef struct sd_dhcp_server_lease {
         unsigned n_ref;
diff --git a/src/libsystemd-network/dhcp6-client-internal.h b/src/libsystemd-network/dhcp6-client-internal.h
index 6c17f5749b..1a84053735 100644
--- a/src/libsystemd-network/dhcp6-client-internal.h
+++ b/src/libsystemd-network/dhcp6-client-internal.h
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
+#include "forward.h"
 #include "sd-dhcp6-client.h"
 
 int dhcp6_client_set_state_callback(
diff --git a/src/libsystemd-network/dhcp6-internal.h b/src/libsystemd-network/dhcp6-internal.h
index 2ef8dc8690..5762966c26 100644
--- a/src/libsystemd-network/dhcp6-internal.h
+++ b/src/libsystemd-network/dhcp6-internal.h
@@ -9,19 +9,13 @@
 #include <netinet/in.h>
 
 #include "sd-dhcp6-client.h"
-#include "sd-event.h"
 
 #include "dhcp-duid-internal.h"
-#include "dhcp6-client-internal.h"
 #include "dhcp6-option.h"
 #include "dhcp6-protocol.h"
-#include "ether-addr-util.h"
-#include "hashmap.h"
-#include "macro.h"
+#include "forward.h"
 #include "network-common.h"
-#include "ordered-set.h"
 #include "sparse-endian.h"
-#include "time-util.h"
 
 /* what to request from the server, addresses (IA_NA) and/or prefixes (IA_PD) */
 typedef enum DHCP6RequestIA {
diff --git a/src/libsystemd-network/dhcp6-lease-internal.h b/src/libsystemd-network/dhcp6-lease-internal.h
index 62c3858841..ac7fb588ef 100644
--- a/src/libsystemd-network/dhcp6-lease-internal.h
+++ b/src/libsystemd-network/dhcp6-lease-internal.h
@@ -5,15 +5,11 @@
   Copyright © 2014-2015 Intel Corporation. All rights reserved.
 ***/
 
-#include <inttypes.h>
-
 #include "sd-dhcp6-lease.h"
 
 #include "dhcp6-option.h"
 #include "dhcp6-protocol.h"
-#include "dns-resolver-internal.h"
-#include "macro.h"
-#include "set.h"
+#include "forward.h"
 #include "time-util.h"
 
 struct sd_dhcp6_lease {
diff --git a/src/libsystemd-network/dhcp6-network.c b/src/libsystemd-network/dhcp6-network.c
index dbe4253164..b794d8858c 100644
--- a/src/libsystemd-network/dhcp6-network.c
+++ b/src/libsystemd-network/dhcp6-network.c
@@ -3,14 +3,9 @@
   Copyright © 2014 Intel Corporation. All rights reserved.
 ***/
 
-#include <errno.h>
-#include <linux/if_packet.h>
 #include <netinet/in.h>
-#include <netinet/ip6.h>
 #include <stdio.h>
 #include <string.h>
-#include <sys/types.h>
-#include <unistd.h>
 
 #include "dhcp6-internal.h"
 #include "dhcp6-protocol.h"
diff --git a/src/libsystemd-network/dhcp6-option.c b/src/libsystemd-network/dhcp6-option.c
index 2767c6f7fc..1de4bacd1b 100644
--- a/src/libsystemd-network/dhcp6-option.c
+++ b/src/libsystemd-network/dhcp6-option.c
@@ -3,10 +3,10 @@
   Copyright © 2014-2015 Intel Corporation. All rights reserved.
 ***/
 
-#include <errno.h>
 #include <netinet/in.h>
 
 #include "sd-dhcp6-client.h"
+#include "sd-dhcp6-option.h"
 
 #include "alloc-util.h"
 #include "dhcp6-internal.h"
@@ -14,10 +14,11 @@
 #include "dhcp6-protocol.h"
 #include "dns-def.h"
 #include "dns-domain.h"
-#include "errno-util.h"
 #include "escape.h"
 #include "memory-util.h"
 #include "network-common.h"
+#include "ordered-set.h"
+#include "string-util.h"
 #include "strv.h"
 #include "unaligned.h"
 
diff --git a/src/libsystemd-network/dhcp6-option.h b/src/libsystemd-network/dhcp6-option.h
index 614b4f8a43..9deee41ae4 100644
--- a/src/libsystemd-network/dhcp6-option.h
+++ b/src/libsystemd-network/dhcp6-option.h
@@ -1,12 +1,12 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "sd-dhcp6-client.h"
+#include <netinet/in.h>
 
-#include "hash-funcs.h"
+#include "sd-dhcp6-option.h" /* IWYU pragma: export */
+
+#include "forward.h"
 #include "list.h"
-#include "macro.h"
-#include "ordered-set.h"
 #include "sparse-endian.h"
 
 typedef struct sd_dhcp6_option {
diff --git a/src/libsystemd-network/dhcp6-protocol.h b/src/libsystemd-network/dhcp6-protocol.h
index 39f5040f9d..75608348cd 100644
--- a/src/libsystemd-network/dhcp6-protocol.h
+++ b/src/libsystemd-network/dhcp6-protocol.h
@@ -5,11 +5,7 @@
   Copyright © 2014 Intel Corporation. All rights reserved.
 ***/
 
-#include <errno.h>
-#include <netinet/ip6.h>
-#include <netinet/udp.h>
-
-#include "macro.h"
+#include "forward.h"
 #include "sparse-endian.h"
 
 struct DHCP6Message {
diff --git a/src/libsystemd-network/dns-resolver-internal.h b/src/libsystemd-network/dns-resolver-internal.h
index a02aa05bf2..1ae775096d 100644
--- a/src/libsystemd-network/dns-resolver-internal.h
+++ b/src/libsystemd-network/dns-resolver-internal.h
@@ -1,12 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <errno.h>
-
 #include "sd-dns-resolver.h"
 
-#include "list.h"
-#include "macro.h"
+#include "forward.h"
 #include "socket-netlink.h"
 
 /* https://www.iana.org/assignments/dns-svcb/dns-svcb.xhtml#dns-svcparamkeys */
@@ -30,7 +27,7 @@ const char* format_dns_svc_param_key(uint16_t i, char buf[static DECIMAL_STR_MAX
 
 /* Represents a "designated resolver" */
 /* typedef struct sd_dns_resolver sd_dns_resolver; */
-struct sd_dns_resolver {
+typedef struct sd_dns_resolver {
         uint16_t priority;
         char *auth_name;
         int family;
@@ -39,7 +36,7 @@ struct sd_dns_resolver {
         sd_dns_alpn_flags transports;
         uint16_t port;
         char *dohpath;
-};
+} sd_dns_resolver;
 
 void siphash24_compress_resolver(const sd_dns_resolver *res, struct siphash *state);
 
diff --git a/src/libsystemd-network/fuzz-dhcp-client.c b/src/libsystemd-network/fuzz-dhcp-client.c
index 3ed21ee175..23471f89fc 100644
--- a/src/libsystemd-network/fuzz-dhcp-client.c
+++ b/src/libsystemd-network/fuzz-dhcp-client.c
@@ -1,13 +1,8 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
 #include <sys/socket.h>
-#include <unistd.h>
 
-#include "alloc-util.h"
-#include "dhcp-lease-internal.h"
 #include "dhcp-network.h"
-#include "fs-util.h"
 #include "fuzz.h"
 #include "network-internal.h"
 #include "sd-dhcp-client.c"
diff --git a/src/libsystemd-network/fuzz-dhcp-server-relay.c b/src/libsystemd-network/fuzz-dhcp-server-relay.c
index 3cfcab7e99..62c2d822f2 100644
--- a/src/libsystemd-network/fuzz-dhcp-server-relay.c
+++ b/src/libsystemd-network/fuzz-dhcp-server-relay.c
@@ -1,8 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <fcntl.h>
-#include <sys/stat.h>
-#include <sys/types.h>
 
 #include "fuzz.h"
 #include "sd-dhcp-server.c"
diff --git a/src/libsystemd-network/fuzz-dhcp-server.c b/src/libsystemd-network/fuzz-dhcp-server.c
index 3f83aae34d..47e3c9efa9 100644
--- a/src/libsystemd-network/fuzz-dhcp-server.c
+++ b/src/libsystemd-network/fuzz-dhcp-server.c
@@ -1,11 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <fcntl.h>
-#include <sys/stat.h>
-#include <sys/types.h>
+#include <net/if_arp.h>
 
 #include "fuzz.h"
-#include "path-util.h"
 #include "rm-rf.h"
 #include "sd-dhcp-server.c"
 #include "tmpfile-util.h"
diff --git a/src/libsystemd-network/fuzz-dhcp6-client.c b/src/libsystemd-network/fuzz-dhcp6-client.c
index 2b6e3357e9..aaa95c2b9d 100644
--- a/src/libsystemd-network/fuzz-dhcp6-client.c
+++ b/src/libsystemd-network/fuzz-dhcp6-client.c
@@ -1,12 +1,12 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <stdlib.h>
 #include <unistd.h>
 
 #include "sd-dhcp6-client.h"
 #include "sd-event.h"
 
 #include "dhcp6-internal.h"
-#include "event-util.h"
 #include "fd-util.h"
 #include "fuzz.h"
 
diff --git a/src/libsystemd-network/fuzz-lldp-rx.c b/src/libsystemd-network/fuzz-lldp-rx.c
index 00e6d81809..8567e433ae 100644
--- a/src/libsystemd-network/fuzz-lldp-rx.c
+++ b/src/libsystemd-network/fuzz-lldp-rx.c
@@ -1,9 +1,10 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
+#include <sys/socket.h>
 #include <unistd.h>
 
 #include "sd-event.h"
+#include "sd-json.h"
 #include "sd-lldp-rx.h"
 
 #include "fd-util.h"
diff --git a/src/libsystemd-network/fuzz-ndisc-rs.c b/src/libsystemd-network/fuzz-ndisc-rs.c
index e6ee76895f..0576821666 100644
--- a/src/libsystemd-network/fuzz-ndisc-rs.c
+++ b/src/libsystemd-network/fuzz-ndisc-rs.c
@@ -1,20 +1,18 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <arpa/inet.h>
-#include <netinet/icmp6.h>
 #include <unistd.h>
 
+#include "sd-event.h"
 #include "sd-ndisc.h"
 #include "sd-radv.h"
 
-#include "alloc-util.h"
 #include "fd-util.h"
 #include "fuzz.h"
 #include "icmp6-packet.h"
 #include "icmp6-test-util.h"
-#include "ndisc-internal.h"
+#include "icmp6-util.h"
 #include "ndisc-option.h"
-#include "socket-util.h"
+#include "set.h"
 
 static void test_with_sd_ndisc(const uint8_t *data, size_t size) {
         struct ether_addr mac_addr = {
diff --git a/src/libsystemd-network/icmp6-packet.c b/src/libsystemd-network/icmp6-packet.c
index fe531ba14a..b4e8e7f851 100644
--- a/src/libsystemd-network/icmp6-packet.c
+++ b/src/libsystemd-network/icmp6-packet.c
@@ -6,8 +6,7 @@
 #include "icmp6-packet.h"
 #include "icmp6-util.h"
 #include "in-addr-util.h"
-#include "iovec-util.h"
-#include "network-common.h"
+#include "log.h"
 #include "socket-util.h"
 
 DEFINE_TRIVIAL_REF_UNREF_FUNC(ICMP6Packet, icmp6_packet, mfree);
diff --git a/src/libsystemd-network/icmp6-packet.h b/src/libsystemd-network/icmp6-packet.h
index cb961ff641..3ae33a2039 100644
--- a/src/libsystemd-network/icmp6-packet.h
+++ b/src/libsystemd-network/icmp6-packet.h
@@ -1,11 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <inttypes.h>
 #include <netinet/in.h>
 
-#include "macro.h"
-#include "memory-util.h"
+#include "forward.h"
 #include "time-util.h"
 
 typedef struct ICMP6Packet {
diff --git a/src/libsystemd-network/icmp6-test-util.c b/src/libsystemd-network/icmp6-test-util.c
index 3c781095bc..761f6a0fb5 100644
--- a/src/libsystemd-network/icmp6-test-util.c
+++ b/src/libsystemd-network/icmp6-test-util.c
@@ -1,11 +1,12 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <netinet/icmp6.h>
-#include <netinet/ip6.h>
+#include <sys/uio.h>
 #include <unistd.h>
 
 #include "fd-util.h"
 #include "icmp6-test-util.h"
+#include "icmp6-util.h"
+#include "time-util.h"
 
 int test_fd[2] = EBADF_PAIR;
 
diff --git a/src/libsystemd-network/icmp6-test-util.h b/src/libsystemd-network/icmp6-test-util.h
index d7b0cc84b3..124cab5552 100644
--- a/src/libsystemd-network/icmp6-test-util.h
+++ b/src/libsystemd-network/icmp6-test-util.h
@@ -1,6 +1,4 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "icmp6-util.h"
-
 extern int test_fd[2];
diff --git a/src/libsystemd-network/icmp6-util.c b/src/libsystemd-network/icmp6-util.c
index 58c473c048..4347f8b723 100644
--- a/src/libsystemd-network/icmp6-util.c
+++ b/src/libsystemd-network/icmp6-util.c
@@ -3,21 +3,14 @@
   Copyright © 2014 Intel Corporation. All rights reserved.
 ***/
 
-#include <errno.h>
-#include <linux/if_packet.h>
-#include <net/if.h>
 #include <netinet/icmp6.h>
 #include <netinet/in.h>
-#include <netinet/ip6.h>
 #include <stdio.h>
 #include <string.h>
-#include <sys/types.h>
-#include <unistd.h>
 
 #include "fd-util.h"
 #include "icmp6-util.h"
 #include "in-addr-util.h"
-#include "iovec-util.h"
 #include "network-common.h"
 #include "socket-util.h"
 
diff --git a/src/libsystemd-network/icmp6-util.h b/src/libsystemd-network/icmp6-util.h
index 9e5063f51b..a904564dfe 100644
--- a/src/libsystemd-network/icmp6-util.h
+++ b/src/libsystemd-network/icmp6-util.h
@@ -5,12 +5,9 @@
   Copyright © 2014-2015 Intel Corporation. All rights reserved.
 ***/
 
-#include <net/ethernet.h>
 #include <netinet/in.h>
-#include <stdbool.h>
-#include <sys/uio.h>
 
-#include "time-util.h"
+#include "forward.h"
 
 #define IN6_ADDR_ALL_ROUTERS_MULTICAST                                  \
         ((const struct in6_addr) { { {                                  \
diff --git a/src/libsystemd-network/lldp-neighbor.c b/src/libsystemd-network/lldp-neighbor.c
index dd2a221403..e93cf566fa 100644
--- a/src/libsystemd-network/lldp-neighbor.c
+++ b/src/libsystemd-network/lldp-neighbor.c
@@ -3,12 +3,16 @@
 #include "alloc-util.h"
 #include "escape.h"
 #include "ether-addr-util.h"
+#include "hashmap.h"
 #include "hexdecoct.h"
 #include "in-addr-util.h"
 #include "json-util.h"
 #include "lldp-neighbor.h"
+#include "lldp-rx-internal.h"
 #include "memory-util.h"
 #include "missing_network.h"
+#include "prioq.h"
+#include "siphash24.h"
 #include "unaligned.h"
 
 static void lldp_neighbor_id_hash_func(const LLDPNeighborID *id, struct siphash *state) {
diff --git a/src/libsystemd-network/lldp-neighbor.h b/src/libsystemd-network/lldp-neighbor.h
index f7945c2edf..9a2dc7d81d 100644
--- a/src/libsystemd-network/lldp-neighbor.h
+++ b/src/libsystemd-network/lldp-neighbor.h
@@ -1,15 +1,12 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <inttypes.h>
-#include <stdbool.h>
-#include <sys/types.h>
+#include <net/ethernet.h>
 
-#include "sd-json.h"
 #include "sd-lldp-rx.h"
 
-#include "hash-funcs.h"
-#include "lldp-rx-internal.h"
+#include "forward.h"
+#include "memory-util.h"
 #include "time-util.h"
 
 typedef struct LLDPNeighborID {
diff --git a/src/libsystemd-network/lldp-network.c b/src/libsystemd-network/lldp-network.c
index 598669fe20..38e5ddb691 100644
--- a/src/libsystemd-network/lldp-network.c
+++ b/src/libsystemd-network/lldp-network.c
@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <linux/filter.h>
-#include <netinet/if_ether.h>
 
 #include "fd-util.h"
 #include "lldp-network.h"
diff --git a/src/libsystemd-network/lldp-network.h b/src/libsystemd-network/lldp-network.h
index bc69b324c2..b2ae00fb4a 100644
--- a/src/libsystemd-network/lldp-network.h
+++ b/src/libsystemd-network/lldp-network.h
@@ -1,6 +1,4 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "sd-event.h"
-
 int lldp_network_bind_raw_socket(int ifindex);
diff --git a/src/libsystemd-network/lldp-rx-internal.h b/src/libsystemd-network/lldp-rx-internal.h
index 33f0add399..9c451c183d 100644
--- a/src/libsystemd-network/lldp-rx-internal.h
+++ b/src/libsystemd-network/lldp-rx-internal.h
@@ -1,13 +1,12 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "sd-event.h"
-#include "sd-json.h"
-#include "sd-lldp-rx.h"
+#include <net/ethernet.h>
+
+#include "sd-lldp-rx.h" /* IWYU pragma: export */
 
-#include "hashmap.h"
 #include "network-common.h"
-#include "prioq.h"
+#include "forward.h"
 
 struct sd_lldp_rx {
         unsigned n_ref;
diff --git a/src/libsystemd-network/ndisc-internal.h b/src/libsystemd-network/ndisc-internal.h
index 4e82fd5a86..f0488cff8d 100644
--- a/src/libsystemd-network/ndisc-internal.h
+++ b/src/libsystemd-network/ndisc-internal.h
@@ -5,8 +5,13 @@
   Copyright © 2014 Intel Corporation. All rights reserved.
 ***/
 
-#include "sd-ndisc.h"
+#include <net/ethernet.h>
+#include <netinet/in.h>
 
+#include "sd-event.h"
+#include "sd-ndisc.h" /* IWYU pragma: export */
+
+#include "forward.h"
 #include "network-common.h"
 #include "time-util.h"
 
@@ -14,7 +19,7 @@
 #define NDISC_MAX_ROUTER_SOLICITATION_INTERVAL (3600U * USEC_PER_SEC)
 #define NDISC_MAX_ROUTER_SOLICITATIONS 3U
 
-struct sd_ndisc {
+typedef struct sd_ndisc {
         unsigned n_ref;
 
         int ifindex;
@@ -35,7 +40,7 @@ struct sd_ndisc {
 
         sd_ndisc_callback_t callback;
         void *userdata;
-};
+} sd_ndisc;
 
 const char* ndisc_event_to_string(sd_ndisc_event_t e) _const_;
 sd_ndisc_event_t ndisc_event_from_string(const char *s) _pure_;
diff --git a/src/libsystemd-network/ndisc-neighbor-internal.h b/src/libsystemd-network/ndisc-neighbor-internal.h
index aee655665e..295c093b43 100644
--- a/src/libsystemd-network/ndisc-neighbor-internal.h
+++ b/src/libsystemd-network/ndisc-neighbor-internal.h
@@ -1,12 +1,11 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "sd-ndisc.h"
+#include <linux/in6.h>
 
-#include "icmp6-packet.h"
-#include "set.h"
+#include "forward.h"
 
-struct sd_ndisc_neighbor {
+typedef struct sd_ndisc_neighbor {
         unsigned n_ref;
 
         ICMP6Packet *packet;
@@ -15,7 +14,7 @@ struct sd_ndisc_neighbor {
         struct in6_addr target_address;
 
         Set *options;
-};
+} sd_ndisc_neighbor;
 
 sd_ndisc_neighbor* ndisc_neighbor_new(ICMP6Packet *packet);
 int ndisc_neighbor_parse(sd_ndisc *nd, sd_ndisc_neighbor *na);
diff --git a/src/libsystemd-network/ndisc-option.c b/src/libsystemd-network/ndisc-option.c
index d0f95c896f..d66f3d235e 100644
--- a/src/libsystemd-network/ndisc-option.c
+++ b/src/libsystemd-network/ndisc-option.c
@@ -3,18 +3,24 @@
 #include <linux/ipv6.h>
 #include <netinet/icmp6.h>
 
+#include "sd-ndisc-protocol.h"
+
 #include "alloc-util.h"
 #include "dns-def.h"
 #include "dns-domain.h"
 #include "dns-resolver-internal.h"
 #include "ether-addr-util.h"
+#include "hash-funcs.h"
 #include "hostname-util.h"
+#include "icmp6-packet.h"
 #include "icmp6-util.h"
 #include "in-addr-util.h"
 #include "iovec-util.h"
-#include "missing_network.h"
 #include "ndisc-option.h"
 #include "network-common.h"
+#include "set.h"
+#include "siphash24.h"
+#include "string-util.h"
 #include "strv.h"
 #include "unaligned.h"
 
@@ -1664,6 +1670,14 @@ int ndisc_parse_options(ICMP6Packet *packet, Set **ret_options) {
         return 0;
 }
 
+sd_ndisc_option* ndisc_option_get(Set *options, const sd_ndisc_option *p) {
+        return set_get(options, ASSERT_PTR(p));
+}
+
+sd_ndisc_option* ndisc_option_get_by_type(Set *options, uint8_t type) {
+        return ndisc_option_get(options, &(const sd_ndisc_option) { .type = type });
+}
+
 int ndisc_option_get_mac(Set *options, uint8_t type, struct ether_addr *ret) {
         assert(IN_SET(type, SD_NDISC_OPTION_SOURCE_LL_ADDRESS, SD_NDISC_OPTION_TARGET_LL_ADDRESS));
 
@@ -1676,6 +1690,10 @@ int ndisc_option_get_mac(Set *options, uint8_t type, struct ether_addr *ret) {
         return 0;
 }
 
+void ndisc_option_remove(Set *options, const sd_ndisc_option *p) {
+        ndisc_option_free(set_remove(options, ASSERT_PTR(p)));
+}
+
 int ndisc_send(int fd, const struct in6_addr *dst, const struct icmp6_hdr *hdr, Set *options, usec_t timestamp) {
         int r;
 
diff --git a/src/libsystemd-network/ndisc-option.h b/src/libsystemd-network/ndisc-option.h
index d9408be79a..8517f68dfb 100644
--- a/src/libsystemd-network/ndisc-option.h
+++ b/src/libsystemd-network/ndisc-option.h
@@ -1,19 +1,11 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <inttypes.h>
 #include <net/ethernet.h>
-#include <netinet/icmp6.h>
-#include <netinet/in.h>
 #include <netinet/ip6.h>
-#include <sys/uio.h>
 
 #include "sd-dns-resolver.h"
-#include "sd-ndisc-protocol.h"
 
-#include "icmp6-packet.h"
-#include "macro.h"
-#include "set.h"
 #include "time-util.h"
 
 typedef struct sd_ndisc_raw {
@@ -131,17 +123,11 @@ int ndisc_option_parse(
 
 int ndisc_parse_options(ICMP6Packet *p, Set **ret_options);
 
-static inline sd_ndisc_option* ndisc_option_get(Set *options, const sd_ndisc_option *p) {
-        return set_get(options, ASSERT_PTR(p));
-}
-static inline sd_ndisc_option* ndisc_option_get_by_type(Set *options, uint8_t type) {
-        return ndisc_option_get(options, &(const sd_ndisc_option) { .type = type });
-}
+sd_ndisc_option* ndisc_option_get(Set *options, const sd_ndisc_option *p);
+sd_ndisc_option* ndisc_option_get_by_type(Set *options, uint8_t type);
 int ndisc_option_get_mac(Set *options, uint8_t type, struct ether_addr *ret);
 
-static inline void ndisc_option_remove(Set *options, const sd_ndisc_option *p) {
-        ndisc_option_free(set_remove(options, ASSERT_PTR(p)));
-}
+void ndisc_option_remove(Set *options, const sd_ndisc_option *p);
 static inline void ndisc_option_remove_by_type(Set *options, uint8_t type) {
         ndisc_option_remove(options, &(const sd_ndisc_option) { .type = type });
 }
diff --git a/src/libsystemd-network/ndisc-redirect-internal.h b/src/libsystemd-network/ndisc-redirect-internal.h
index e35263a05d..77d6f8b88f 100644
--- a/src/libsystemd-network/ndisc-redirect-internal.h
+++ b/src/libsystemd-network/ndisc-redirect-internal.h
@@ -1,12 +1,11 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "sd-ndisc.h"
+#include <linux/in6.h>
 
-#include "icmp6-packet.h"
-#include "set.h"
+#include "forward.h"
 
-struct sd_ndisc_redirect {
+typedef struct sd_ndisc_redirect {
         unsigned n_ref;
 
         ICMP6Packet *packet;
@@ -15,7 +14,7 @@ struct sd_ndisc_redirect {
         struct in6_addr destination_address;
 
         Set *options;
-};
+} sd_ndisc_redirect;
 
 sd_ndisc_redirect* ndisc_redirect_new(ICMP6Packet *packet);
 int ndisc_redirect_parse(sd_ndisc *nd, sd_ndisc_redirect *rd);
diff --git a/src/libsystemd-network/ndisc-router-internal.h b/src/libsystemd-network/ndisc-router-internal.h
index 6df72fd3cc..025cc146a4 100644
--- a/src/libsystemd-network/ndisc-router-internal.h
+++ b/src/libsystemd-network/ndisc-router-internal.h
@@ -8,10 +8,10 @@
 #include "sd-ndisc.h"
 
 #include "icmp6-packet.h"
+#include "iterator.h"
 #include "ndisc-option.h"
-#include "time-util.h"
 
-struct sd_ndisc_router {
+typedef struct sd_ndisc_router {
         unsigned n_ref;
 
         ICMP6Packet *packet;
@@ -28,7 +28,7 @@ struct sd_ndisc_router {
         Set *options;
         Iterator iterator;
         sd_ndisc_option *current_option;
-};
+} sd_ndisc_router;
 
 sd_ndisc_router* ndisc_router_new(ICMP6Packet *packet);
 int ndisc_router_parse(sd_ndisc *nd, sd_ndisc_router *rt);
diff --git a/src/libsystemd-network/ndisc-router-solicit-internal.h b/src/libsystemd-network/ndisc-router-solicit-internal.h
index 6f0b0af13a..2186238a6f 100644
--- a/src/libsystemd-network/ndisc-router-solicit-internal.h
+++ b/src/libsystemd-network/ndisc-router-solicit-internal.h
@@ -1,18 +1,15 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "sd-radv.h"
+#include "forward.h"
 
-#include "icmp6-packet.h"
-#include "set.h"
-
-struct sd_ndisc_router_solicit {
+typedef struct sd_ndisc_router_solicit {
         unsigned n_ref;
 
         ICMP6Packet *packet;
 
         Set *options;
-};
+} sd_ndisc_router_solicit;
 
 sd_ndisc_router_solicit* ndisc_router_solicit_new(ICMP6Packet *packet);
 int ndisc_router_solicit_parse(sd_radv *ra, sd_ndisc_router_solicit *rs);
diff --git a/src/libsystemd-network/network-common.h b/src/libsystemd-network/network-common.h
index 1750f1810b..933ce170b7 100644
--- a/src/libsystemd-network/network-common.h
+++ b/src/libsystemd-network/network-common.h
@@ -1,8 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <sys/socket.h>
-
+#include "forward.h"
 #include "log-link.h"
 #include "sparse-endian.h"
 #include "time-util.h"
diff --git a/src/libsystemd-network/network-internal.c b/src/libsystemd-network/network-internal.c
index 1563655b79..e7c22c9b76 100644
--- a/src/libsystemd-network/network-internal.c
+++ b/src/libsystemd-network/network-internal.c
@@ -1,19 +1,17 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <arpa/inet.h>
-#include <linux/if.h>
-#include <netinet/ether.h>
-
-#include "sd-ndisc.h"
+#include <stdio.h>
 
 #include "alloc-util.h"
 #include "dhcp-lease-internal.h"
+#include "dns-resolver-internal.h"
 #include "extract-word.h"
 #include "hexdecoct.h"
 #include "in-addr-util.h"
-#include "log.h"
 #include "network-internal.h"
 #include "parse-util.h"
+#include "string-util.h"
 #include "strv.h"
 
 size_t serialize_in_addrs(FILE *f,
diff --git a/src/libsystemd-network/network-internal.h b/src/libsystemd-network/network-internal.h
index 6a102e92c4..aace983d5b 100644
--- a/src/libsystemd-network/network-internal.h
+++ b/src/libsystemd-network/network-internal.h
@@ -1,10 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
-#include <stdio.h>
-
-#include "sd-dhcp-lease.h"
+#include "forward.h"
 
 size_t serialize_in_addrs(FILE *f,
                           const struct in_addr *addresses,
diff --git a/src/libsystemd-network/radv-internal.h b/src/libsystemd-network/radv-internal.h
index 5ed7784a85..0e34176e8c 100644
--- a/src/libsystemd-network/radv-internal.h
+++ b/src/libsystemd-network/radv-internal.h
@@ -5,14 +5,10 @@
   Copyright © 2017 Intel Corporation. All rights reserved.
 ***/
 
-#include <netinet/icmp6.h>
+#include <netinet/in.h>
 
-#include "sd-radv.h"
-
-#include "list.h"
-#include "ndisc-option.h"
+#include "forward.h"
 #include "network-common.h"
-#include "sparse-endian.h"
 #include "time-util.h"
 
 /* RFC 4861 section 6.2.1.
diff --git a/src/libsystemd-network/sd-dhcp-client-id.c b/src/libsystemd-network/sd-dhcp-client-id.c
index d1280fb619..77614718d7 100644
--- a/src/libsystemd-network/sd-dhcp-client-id.c
+++ b/src/libsystemd-network/sd-dhcp-client-id.c
@@ -5,6 +5,8 @@
 #include "iovec-util.h"
 #include "json-util.h"
 #include "log.h"
+#include "siphash24.h"
+#include "string-util.h"
 #include "unaligned.h"
 #include "utf8.h"
 
diff --git a/src/libsystemd-network/sd-dhcp-client.c b/src/libsystemd-network/sd-dhcp-client.c
index 56e9747528..2cb60b92ce 100644
--- a/src/libsystemd-network/sd-dhcp-client.c
+++ b/src/libsystemd-network/sd-dhcp-client.c
@@ -3,13 +3,9 @@
   Copyright © 2013 Intel Corporation. All rights reserved.
 ***/
 
-#include <errno.h>
 #include <linux/if_infiniband.h>
-#include <net/ethernet.h>
 #include <net/if_arp.h>
 #include <stdio.h>
-#include <stdlib.h>
-#include <sys/ioctl.h>
 
 #include "sd-dhcp-client.h"
 
@@ -22,6 +18,7 @@
 #include "dhcp-option.h"
 #include "dhcp-packet.h"
 #include "dns-domain.h"
+#include "errno-util.h"
 #include "ether-addr-util.h"
 #include "event-util.h"
 #include "fd-util.h"
@@ -31,12 +28,12 @@
 #include "network-common.h"
 #include "random-util.h"
 #include "set.h"
+#include "socket-util.h"
 #include "sort-util.h"
 #include "string-table.h"
 #include "string-util.h"
 #include "strv.h"
 #include "time-util.h"
-#include "utf8.h"
 #include "web-util.h"
 
 #define MAX_MAC_ADDR_LEN CONST_MAX(INFINIBAND_ALEN, ETH_ALEN)
diff --git a/src/libsystemd-network/sd-dhcp-duid.c b/src/libsystemd-network/sd-dhcp-duid.c
index 4782ec62d7..b0caa10976 100644
--- a/src/libsystemd-network/sd-dhcp-duid.c
+++ b/src/libsystemd-network/sd-dhcp-duid.c
@@ -1,15 +1,17 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <linux/if_infiniband.h>
-#include <net/ethernet.h>
 #include <net/if_arp.h>
+#include <stdio.h>
 
+#include "alloc-util.h"
 #include "dhcp-duid-internal.h"
 #include "hexdecoct.h"
 #include "netif-util.h"
 #include "network-common.h"
 #include "siphash24.h"
 #include "string-table.h"
+#include "string-util.h"
 #include "unaligned.h"
 
 #define HASH_KEY       SD_ID128_MAKE(80,11,8c,c2,fe,4a,03,ee,3e,d6,0c,6f,36,39,14,09)
diff --git a/src/libsystemd-network/sd-dhcp-lease.c b/src/libsystemd-network/sd-dhcp-lease.c
index 2eb9bf25ee..a98ec7fc63 100644
--- a/src/libsystemd-network/sd-dhcp-lease.c
+++ b/src/libsystemd-network/sd-dhcp-lease.c
@@ -4,11 +4,7 @@
 ***/
 
 #include <arpa/inet.h>
-#include <errno.h>
-#include <stdlib.h>
 #include <sys/stat.h>
-#include <sys/types.h>
-#include <unistd.h>
 
 #include "sd-dhcp-lease.h"
 
diff --git a/src/libsystemd-network/sd-dhcp-server-lease.c b/src/libsystemd-network/sd-dhcp-server-lease.c
index d9ea5304e8..35a1e7bb18 100644
--- a/src/libsystemd-network/sd-dhcp-server-lease.c
+++ b/src/libsystemd-network/sd-dhcp-server-lease.c
@@ -1,14 +1,20 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <sys/stat.h>
+
+#include "sd-event.h"
+
 #include "alloc-util.h"
 #include "dhcp-server-lease-internal.h"
-#include "dns-def.h"
 #include "errno-util.h"
 #include "fd-util.h"
 #include "fs-util.h"
+#include "hashmap.h"
+#include "in-addr-util.h"
 #include "iovec-util.h"
 #include "json-util.h"
 #include "mkdir.h"
+#include "string-util.h"
 #include "tmpfile-util.h"
 
 static sd_dhcp_server_lease* dhcp_server_lease_free(sd_dhcp_server_lease *lease) {
diff --git a/src/libsystemd-network/sd-dhcp-server.c b/src/libsystemd-network/sd-dhcp-server.c
index 88c51d5458..af87b15238 100644
--- a/src/libsystemd-network/sd-dhcp-server.c
+++ b/src/libsystemd-network/sd-dhcp-server.c
@@ -3,10 +3,8 @@
   Copyright © 2013 Intel Corporation. All rights reserved.
 ***/
 
-#include <net/if_arp.h>
-#include <sys/ioctl.h>
-
 #include "sd-dhcp-server.h"
+#include "sd-event.h"
 #include "sd-id128.h"
 
 #include "alloc-util.h"
@@ -16,6 +14,7 @@
 #include "dhcp-server-internal.h"
 #include "dhcp-server-lease-internal.h"
 #include "dns-domain.h"
+#include "errno-util.h"
 #include "fd-util.h"
 #include "in-addr-util.h"
 #include "iovec-util.h"
@@ -24,9 +23,9 @@
 #include "ordered-set.h"
 #include "path-util.h"
 #include "siphash24.h"
+#include "socket-util.h"
 #include "string-util.h"
 #include "unaligned.h"
-#include "utf8.h"
 
 #define DHCP_DEFAULT_LEASE_TIME_USEC USEC_PER_HOUR
 #define DHCP_MAX_LEASE_TIME_USEC (USEC_PER_HOUR*12)
diff --git a/src/libsystemd-network/sd-dhcp6-client.c b/src/libsystemd-network/sd-dhcp6-client.c
index b806a7debb..36585c8554 100644
--- a/src/libsystemd-network/sd-dhcp6-client.c
+++ b/src/libsystemd-network/sd-dhcp6-client.c
@@ -3,27 +3,30 @@
   Copyright © 2014-2015 Intel Corporation. All rights reserved.
 ***/
 
-#include <errno.h>
 #include <linux/if_arp.h>
 #include <linux/if_infiniband.h>
-#include <sys/ioctl.h>
 
 #include "sd-dhcp6-client.h"
+#include "sd-dhcp6-option.h"
 
 #include "alloc-util.h"
 #include "device-util.h"
 #include "dhcp-duid-internal.h"
+#include "dhcp6-client-internal.h"
 #include "dhcp6-internal.h"
 #include "dhcp6-lease-internal.h"
 #include "dns-domain.h"
+#include "errno-util.h"
 #include "event-util.h"
 #include "fd-util.h"
 #include "hostname-util.h"
 #include "in-addr-util.h"
 #include "iovec-util.h"
+#include "ordered-set.h"
 #include "random-util.h"
 #include "socket-util.h"
 #include "sort-util.h"
+#include "string-util.h"
 #include "strv.h"
 #include "web-util.h"
 
diff --git a/src/libsystemd-network/sd-dhcp6-lease.c b/src/libsystemd-network/sd-dhcp6-lease.c
index 2ff1e87a2e..4d8df252c8 100644
--- a/src/libsystemd-network/sd-dhcp6-lease.c
+++ b/src/libsystemd-network/sd-dhcp6-lease.c
@@ -3,14 +3,17 @@
   Copyright © 2014-2015 Intel Corporation. All rights reserved.
 ***/
 
-#include <errno.h>
+#include "sd-dhcp6-option.h"
 
 #include "alloc-util.h"
 #include "dhcp6-internal.h"
 #include "dhcp6-lease-internal.h"
 #include "dns-domain.h"
+#include "dns-resolver-internal.h"
 #include "network-common.h"
+#include "set.h"
 #include "sort-util.h"
+#include "string-util.h"
 #include "strv.h"
 #include "unaligned.h"
 
diff --git a/src/libsystemd-network/sd-dns-resolver.c b/src/libsystemd-network/sd-dns-resolver.c
index 673208106c..e7f69da202 100644
--- a/src/libsystemd-network/sd-dns-resolver.c
+++ b/src/libsystemd-network/sd-dns-resolver.c
@@ -3,8 +3,7 @@
 #include "alloc-util.h"
 #include "dns-resolver-internal.h"
 #include "errno-util.h"
-#include "log.h"
-#include "macro.h"
+#include "siphash24.h"
 #include "socket-netlink.h"
 #include "stdio-util.h"
 #include "string-table.h"
diff --git a/src/libsystemd-network/sd-dns-resolver.h b/src/libsystemd-network/sd-dns-resolver.h
index 5acd4fe4f6..8a574263cc 100644
--- a/src/libsystemd-network/sd-dns-resolver.h
+++ b/src/libsystemd-network/sd-dns-resolver.h
@@ -1,13 +1,10 @@
 #ifndef SD_DNS_RESOLVER_H
 #define SD_DNS_RESOLVER_H
 
-#include <errno.h>
-#include <netinet/in.h>
-#include <stddef.h>
-#include <stdint.h>
-
 #include "_sd-common.h"
 
+#include "forward.h"
+
 _SD_BEGIN_DECLARATIONS;
 
 typedef struct sd_dns_resolver sd_dns_resolver;
diff --git a/src/libsystemd-network/sd-ipv4acd.c b/src/libsystemd-network/sd-ipv4acd.c
index 17db4a53f7..87bf46ad29 100644
--- a/src/libsystemd-network/sd-ipv4acd.c
+++ b/src/libsystemd-network/sd-ipv4acd.c
@@ -3,16 +3,14 @@
   Copyright © 2014 Axis Communications AB. All rights reserved.
 ***/
 
-#include <arpa/inet.h>
-#include <errno.h>
 #include <netinet/if_ether.h>
 #include <stdio.h>
-#include <stdlib.h>
 
 #include "sd-ipv4acd.h"
 
 #include "alloc-util.h"
 #include "arp-util.h"
+#include "errno-util.h"
 #include "ether-addr-util.h"
 #include "event-util.h"
 #include "fd-util.h"
@@ -20,7 +18,7 @@
 #include "memory-util.h"
 #include "network-common.h"
 #include "random-util.h"
-#include "siphash24.h"
+#include "socket-util.h"
 #include "string-table.h"
 #include "string-util.h"
 #include "time-util.h"
diff --git a/src/libsystemd-network/sd-ipv4ll.c b/src/libsystemd-network/sd-ipv4ll.c
index 557c145509..b679d206e6 100644
--- a/src/libsystemd-network/sd-ipv4ll.c
+++ b/src/libsystemd-network/sd-ipv4ll.c
@@ -3,11 +3,6 @@
   Copyright © 2014 Axis Communications AB. All rights reserved.
 ***/
 
-#include <arpa/inet.h>
-#include <errno.h>
-#include <stdio.h>
-#include <stdlib.h>
-
 #include "sd-id128.h"
 #include "sd-ipv4acd.h"
 #include "sd-ipv4ll.h"
@@ -16,10 +11,8 @@
 #include "ether-addr-util.h"
 #include "in-addr-util.h"
 #include "network-common.h"
-#include "random-util.h"
 #include "siphash24.h"
 #include "sparse-endian.h"
-#include "string-util.h"
 
 #define IPV4LL_NETWORK UINT32_C(0xA9FE0000)
 #define IPV4LL_NETMASK UINT32_C(0xFFFF0000)
diff --git a/src/libsystemd-network/sd-lldp-rx.c b/src/libsystemd-network/sd-lldp-rx.c
index 029ee0282c..288ed2ee96 100644
--- a/src/libsystemd-network/sd-lldp-rx.c
+++ b/src/libsystemd-network/sd-lldp-rx.c
@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <arpa/inet.h>
 #include <linux/sockios.h>
 #include <sys/ioctl.h>
 
@@ -8,17 +7,21 @@
 #include "sd-lldp-rx.h"
 
 #include "alloc-util.h"
+#include "errno-util.h"
 #include "ether-addr-util.h"
 #include "event-util.h"
 #include "fd-util.h"
+#include "hashmap.h"
 #include "lldp-neighbor.h"
 #include "lldp-network.h"
 #include "lldp-rx-internal.h"
 #include "memory-util.h"
 #include "network-common.h"
+#include "prioq.h"
 #include "socket-util.h"
 #include "sort-util.h"
 #include "string-table.h"
+#include "string-util.h"
 
 #define LLDP_DEFAULT_NEIGHBORS_MAX 128U
 
diff --git a/src/libsystemd-network/sd-lldp-tx.c b/src/libsystemd-network/sd-lldp-tx.c
index 38a619168e..9e93a77cd1 100644
--- a/src/libsystemd-network/sd-lldp-tx.c
+++ b/src/libsystemd-network/sd-lldp-tx.c
@@ -1,9 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <arpa/inet.h>
-#include <linux/sockios.h>
-#include <sys/ioctl.h>
-
 #include "sd-event.h"
 #include "sd-id128.h"
 #include "sd-lldp-tx.h"
diff --git a/src/libsystemd-network/sd-ndisc-neighbor.c b/src/libsystemd-network/sd-ndisc-neighbor.c
index 1bb6ebf610..5ce1da06da 100644
--- a/src/libsystemd-network/sd-ndisc-neighbor.c
+++ b/src/libsystemd-network/sd-ndisc-neighbor.c
@@ -5,10 +5,12 @@
 #include "sd-ndisc.h"
 
 #include "alloc-util.h"
+#include "icmp6-packet.h"
 #include "in-addr-util.h"
 #include "ndisc-internal.h"
 #include "ndisc-neighbor-internal.h"
 #include "ndisc-option.h"
+#include "set.h"
 
 static sd_ndisc_neighbor* ndisc_neighbor_free(sd_ndisc_neighbor *na) {
         if (!na)
diff --git a/src/libsystemd-network/sd-ndisc-redirect.c b/src/libsystemd-network/sd-ndisc-redirect.c
index a1fceb2dff..1637ad36a2 100644
--- a/src/libsystemd-network/sd-ndisc-redirect.c
+++ b/src/libsystemd-network/sd-ndisc-redirect.c
@@ -5,10 +5,12 @@
 #include "sd-ndisc.h"
 
 #include "alloc-util.h"
+#include "icmp6-packet.h"
 #include "in-addr-util.h"
 #include "ndisc-internal.h"
 #include "ndisc-option.h"
 #include "ndisc-redirect-internal.h"
+#include "set.h"
 
 static sd_ndisc_redirect* ndisc_redirect_free(sd_ndisc_redirect *rd) {
         if (!rd)
diff --git a/src/libsystemd-network/sd-ndisc-router-solicit.c b/src/libsystemd-network/sd-ndisc-router-solicit.c
index 742ec9a1d2..ccd14be3cb 100644
--- a/src/libsystemd-network/sd-ndisc-router-solicit.c
+++ b/src/libsystemd-network/sd-ndisc-router-solicit.c
@@ -2,13 +2,16 @@
 
 #include <netinet/icmp6.h>
 
+#include "sd-ndisc-protocol.h"
+#include "sd-ndisc-router-solicit.h"
 #include "sd-radv.h"
 
 #include "alloc-util.h"
-#include "in-addr-util.h"
+#include "icmp6-packet.h"
 #include "ndisc-option.h"
 #include "ndisc-router-solicit-internal.h"
 #include "radv-internal.h"
+#include "set.h"
 
 static sd_ndisc_router_solicit* ndisc_router_solicit_free(sd_ndisc_router_solicit *rs) {
         if (!rs)
diff --git a/src/libsystemd-network/sd-ndisc-router.c b/src/libsystemd-network/sd-ndisc-router.c
index 6936ea34e2..69fab9f6d0 100644
--- a/src/libsystemd-network/sd-ndisc-router.c
+++ b/src/libsystemd-network/sd-ndisc-router.c
@@ -8,12 +8,11 @@
 #include "sd-ndisc.h"
 
 #include "alloc-util.h"
-#include "dns-domain.h"
-#include "dns-resolver-internal.h"
 #include "ndisc-internal.h"
 #include "ndisc-router-internal.h"
+#include "set.h"
 #include "string-table.h"
-#include "unaligned.h"
+#include "string-util.h"
 
 static sd_ndisc_router* ndisc_router_free(sd_ndisc_router *rt) {
         if (!rt)
diff --git a/src/libsystemd-network/sd-ndisc.c b/src/libsystemd-network/sd-ndisc.c
index ca15f942f5..0f2f94eab6 100644
--- a/src/libsystemd-network/sd-ndisc.c
+++ b/src/libsystemd-network/sd-ndisc.c
@@ -21,6 +21,7 @@
 #include "ndisc-router-internal.h"
 #include "network-common.h"
 #include "random-util.h"
+#include "set.h"
 #include "socket-util.h"
 #include "string-table.h"
 #include "string-util.h"
diff --git a/src/libsystemd-network/sd-radv.c b/src/libsystemd-network/sd-radv.c
index 48a198099d..02d6131e8a 100644
--- a/src/libsystemd-network/sd-radv.c
+++ b/src/libsystemd-network/sd-radv.c
@@ -3,31 +3,29 @@
   Copyright © 2017 Intel Corporation. All rights reserved.
 ***/
 
-#include <arpa/inet.h>
 #include <linux/ipv6.h>
 #include <netinet/icmp6.h>
 #include <netinet/in.h>
 
+#include "sd-ndisc-protocol.h"
+#include "sd-ndisc-router-solicit.h"
 #include "sd-radv.h"
 
 #include "alloc-util.h"
-#include "dns-domain.h"
-#include "ether-addr-util.h"
 #include "event-util.h"
 #include "fd-util.h"
+#include "icmp6-packet.h"
 #include "icmp6-util.h"
 #include "in-addr-util.h"
-#include "iovec-util.h"
-#include "macro.h"
 #include "memory-util.h"
+#include "ndisc-option.h"
 #include "ndisc-router-solicit-internal.h"
 #include "network-common.h"
 #include "radv-internal.h"
 #include "random-util.h"
+#include "set.h"
 #include "socket-util.h"
 #include "string-util.h"
-#include "strv.h"
-#include "unaligned.h"
 
 int sd_radv_new(sd_radv **ret) {
         _cleanup_(sd_radv_unrefp) sd_radv *ra = NULL;
diff --git a/src/libsystemd-network/test-acd.c b/src/libsystemd-network/test-acd.c
index c00e87605a..e85a9d267a 100644
--- a/src/libsystemd-network/test-acd.c
+++ b/src/libsystemd-network/test-acd.c
@@ -1,10 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
-#include <linux/veth.h>
-#include <net/if.h>
-#include <stdlib.h>
-#include <unistd.h>
+#include <net/ethernet.h>
 
 #include "sd-event.h"
 #include "sd-ipv4acd.h"
diff --git a/src/libsystemd-network/test-dhcp-client.c b/src/libsystemd-network/test-dhcp-client.c
index fe2a88d8f3..72d8ad4d0c 100644
--- a/src/libsystemd-network/test-dhcp-client.c
+++ b/src/libsystemd-network/test-dhcp-client.c
@@ -3,10 +3,9 @@
   Copyright © 2013 Intel Corporation. All rights reserved.
 ***/
 
-#include <errno.h>
-#include <net/if.h>
 #include <net/if_arp.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <sys/socket.h>
 #include <unistd.h>
 #if HAVE_VALGRIND_VALGRIND_H
@@ -14,6 +13,7 @@
 #endif
 
 #include "sd-dhcp-client.h"
+#include "sd-dhcp-lease.h"
 #include "sd-event.h"
 
 #include "alloc-util.h"
@@ -24,7 +24,6 @@
 #include "ether-addr-util.h"
 #include "fd-util.h"
 #include "log.h"
-#include "random-util.h"
 #include "tests.h"
 
 static struct hw_addr_data hw_addr = {
diff --git a/src/libsystemd-network/test-dhcp-option.c b/src/libsystemd-network/test-dhcp-option.c
index 2a07256ea0..9e36e03859 100644
--- a/src/libsystemd-network/test-dhcp-option.c
+++ b/src/libsystemd-network/test-dhcp-option.c
@@ -1,17 +1,12 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
 #include <net/if_arp.h>
-#include <stdbool.h>
 #include <stdio.h>
 #include <string.h>
 
 #include "alloc-util.h"
 #include "dhcp-option.h"
 #include "dhcp-packet.h"
-#include "ether-addr-util.h"
-#include "log.h"
-#include "macro.h"
 #include "memory-util.h"
 #include "tests.h"
 
diff --git a/src/libsystemd-network/test-dhcp-server.c b/src/libsystemd-network/test-dhcp-server.c
index a067fc0da5..61189fe545 100644
--- a/src/libsystemd-network/test-dhcp-server.c
+++ b/src/libsystemd-network/test-dhcp-server.c
@@ -3,13 +3,14 @@
   Copyright © 2013 Intel Corporation. All rights reserved.
 ***/
 
-#include <errno.h>
 #include <net/if_arp.h>
 
 #include "sd-dhcp-server.h"
 #include "sd-event.h"
 
 #include "dhcp-server-internal.h"
+#include "hashmap.h"
+#include "siphash24.h"
 #include "tests.h"
 
 static void test_pool(struct in_addr *address, unsigned size, int ret) {
diff --git a/src/libsystemd-network/test-dhcp6-client.c b/src/libsystemd-network/test-dhcp6-client.c
index 195aa14594..0775209e02 100644
--- a/src/libsystemd-network/test-dhcp6-client.c
+++ b/src/libsystemd-network/test-dhcp6-client.c
@@ -5,23 +5,20 @@
 
 #include <net/ethernet.h>
 #include <net/if_arp.h>
-#include <stdbool.h>
 #include <stdio.h>
-#include <sys/types.h>
+#include <stdlib.h>
 #include <unistd.h>
 
 #include "sd-dhcp6-client.h"
+#include "sd-dhcp6-protocol.h"
 #include "sd-event.h"
 
-#include "dhcp-duid-internal.h"
 #include "dhcp6-internal.h"
 #include "dhcp6-lease-internal.h"
 #include "dhcp6-protocol.h"
 #include "fd-util.h"
-#include "macro.h"
+#include "in-addr-util.h"
 #include "memory-util.h"
-#include "socket-util.h"
-#include "string-util.h"
 #include "strv.h"
 #include "tests.h"
 #include "time-util.h"
diff --git a/src/libsystemd-network/test-ipv4ll-manual.c b/src/libsystemd-network/test-ipv4ll-manual.c
index 1fc6d11b88..97f5408702 100644
--- a/src/libsystemd-network/test-ipv4ll-manual.c
+++ b/src/libsystemd-network/test-ipv4ll-manual.c
@@ -1,16 +1,11 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
-#include <linux/veth.h>
-#include <net/if.h>
-#include <stdlib.h>
-#include <unistd.h>
+#include <net/ethernet.h>
 
 #include "sd-event.h"
 #include "sd-ipv4ll.h"
 #include "sd-netlink.h"
 
-#include "alloc-util.h"
 #include "in-addr-util.h"
 #include "log.h"
 #include "parse-util.h"
diff --git a/src/libsystemd-network/test-ipv4ll.c b/src/libsystemd-network/test-ipv4ll.c
index 17c981307b..a26000d5f1 100644
--- a/src/libsystemd-network/test-ipv4ll.c
+++ b/src/libsystemd-network/test-ipv4ll.c
@@ -3,19 +3,15 @@
   Copyright © 2014 Axis Communications AB. All rights reserved.
 ***/
 
-#include <errno.h>
 #include <netinet/if_ether.h>
 #include <stdio.h>
-#include <stdlib.h>
-#include <sys/types.h>
-#include <unistd.h>
 
+#include "sd-event.h"
 #include "sd-ipv4ll.h"
 
 #include "arp-util.h"
 #include "fd-util.h"
-#include "log.h"
-#include "socket-util.h"
+#include "in-addr-util.h"
 #include "tests.h"
 
 static bool verbose = false;
diff --git a/src/libsystemd-network/test-lldp-rx.c b/src/libsystemd-network/test-lldp-rx.c
index 704c9a0015..7f497a4de4 100644
--- a/src/libsystemd-network/test-lldp-rx.c
+++ b/src/libsystemd-network/test-lldp-rx.c
@@ -1,20 +1,15 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <arpa/inet.h>
-#include <errno.h>
-#include <net/ethernet.h>
+#include <linux/if_ether.h>
 #include <stdio.h>
+#include <sys/socket.h>
 #include <unistd.h>
 
 #include "sd-event.h"
 #include "sd-lldp-rx.h"
 
-#include "alloc-util.h"
 #include "fd-util.h"
 #include "lldp-network.h"
-#include "log.h"
-#include "macro.h"
-#include "string-util.h"
 #include "tests.h"
 
 #define TEST_LLDP_PORT "em1"
diff --git a/src/libsystemd-network/test-ndisc-ra.c b/src/libsystemd-network/test-ndisc-ra.c
index cc7007f15a..84dc73e84f 100644
--- a/src/libsystemd-network/test-ndisc-ra.c
+++ b/src/libsystemd-network/test-ndisc-ra.c
@@ -3,18 +3,19 @@
   Copyright © 2017 Intel Corporation. All rights reserved.
 ***/
 
-#include <arpa/inet.h>
+#include <net/ethernet.h>
 #include <netinet/icmp6.h>
 #include <unistd.h>
 
+#include "sd-event.h"
+#include "sd-ndisc-protocol.h"
 #include "sd-radv.h"
 
 #include "alloc-util.h"
-#include "hexdecoct.h"
 #include "icmp6-test-util.h"
+#include "in-addr-util.h"
 #include "radv-internal.h"
 #include "socket-util.h"
-#include "strv.h"
 #include "tests.h"
 
 static struct ether_addr mac_addr = {
diff --git a/src/libsystemd-network/test-ndisc-rs.c b/src/libsystemd-network/test-ndisc-rs.c
index effed11615..71af4c2478 100644
--- a/src/libsystemd-network/test-ndisc-rs.c
+++ b/src/libsystemd-network/test-ndisc-rs.c
@@ -3,7 +3,6 @@
   Copyright © 2014 Intel Corporation. All rights reserved.
 ***/
 
-#include <arpa/inet.h>
 #include <netinet/icmp6.h>
 #include <unistd.h>
 
@@ -14,8 +13,8 @@
 #include "hexdecoct.h"
 #include "icmp6-packet.h"
 #include "icmp6-test-util.h"
+#include "in-addr-util.h"
 #include "ndisc-internal.h"
-#include "socket-util.h"
 #include "strv.h"
 #include "tests.h"
 
diff --git a/src/libsystemd-network/test-ndisc-send.c b/src/libsystemd-network/test-ndisc-send.c
index 52bd9fa637..2b40ea77a3 100644
--- a/src/libsystemd-network/test-ndisc-send.c
+++ b/src/libsystemd-network/test-ndisc-send.c
@@ -1,6 +1,10 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <getopt.h>
+#include <netinet/icmp6.h>
+
+#include "sd-ndisc-protocol.h"
+#include "sd-netlink.h"
 
 #include "alloc-util.h"
 #include "build.h"
@@ -14,7 +18,8 @@
 #include "netlink-util.h"
 #include "network-common.h"
 #include "parse-util.h"
-#include "socket-util.h"
+#include "set.h"
+#include "string-util.h"
 #include "strv.h"
 #include "time-util.h"
 
diff --git a/src/libsystemd-network/test-sd-dhcp-lease.c b/src/libsystemd-network/test-sd-dhcp-lease.c
index 5bb0b39180..32f9a6b9a3 100644
--- a/src/libsystemd-network/test-sd-dhcp-lease.c
+++ b/src/libsystemd-network/test-sd-dhcp-lease.c
@@ -1,11 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
-
 #include "dhcp-lease-internal.h"
-#include "log.h"
-#include "macro.h"
-#include "string-util.h"
 #include "strv.h"
 #include "tests.h"
 
diff --git a/src/libsystemd/sd-bus/bus-common-errors.c b/src/libsystemd/sd-bus/bus-common-errors.c
index 1075c29ed6..812e75a302 100644
--- a/src/libsystemd/sd-bus/bus-common-errors.c
+++ b/src/libsystemd/sd-bus/bus-common-errors.c
@@ -1,7 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
-
 #include "sd-bus.h"
 
 #include "bus-common-errors.h"
diff --git a/src/libsystemd/sd-bus/bus-container.c b/src/libsystemd/sd-bus/bus-container.c
index 54da4169a6..73e86bb78c 100644
--- a/src/libsystemd/sd-bus/bus-container.c
+++ b/src/libsystemd/sd-bus/bus-container.c
@@ -7,6 +7,7 @@
 #include "bus-internal.h"
 #include "bus-socket.h"
 #include "fd-util.h"
+#include "format-util.h"
 #include "log.h"
 #include "namespace-util.h"
 #include "process-util.h"
diff --git a/src/libsystemd/sd-bus/bus-container.h b/src/libsystemd/sd-bus/bus-container.h
index cb503a5970..bca37304c0 100644
--- a/src/libsystemd/sd-bus/bus-container.h
+++ b/src/libsystemd/sd-bus/bus-container.h
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "sd-bus.h"
+#include "forward.h"
 
 int bus_container_connect_socket(sd_bus *b);
diff --git a/src/libsystemd/sd-bus/bus-control.c b/src/libsystemd/sd-bus/bus-control.c
index fdcd5ff2da..daa700ebf5 100644
--- a/src/libsystemd/sd-bus/bus-control.c
+++ b/src/libsystemd/sd-bus/bus-control.c
@@ -1,23 +1,15 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#if HAVE_VALGRIND_MEMCHECK_H
-#include <valgrind/memcheck.h>
-#endif
-
-#include <errno.h>
-#include <stddef.h>
-
 #include "sd-bus.h"
 
 #include "alloc-util.h"
 #include "bus-control.h"
 #include "bus-internal.h"
 #include "bus-message.h"
-#include "capability-util.h"
 #include "fd-util.h"
 #include "log.h"
+#include "pidref.h"
 #include "process-util.h"
-#include "stdio-util.h"
 #include "string-util.h"
 #include "strv.h"
 #include "user-util.h"
diff --git a/src/libsystemd/sd-bus/bus-control.h b/src/libsystemd/sd-bus/bus-control.h
index 1cd4fb88d9..56b4a70cda 100644
--- a/src/libsystemd/sd-bus/bus-control.h
+++ b/src/libsystemd/sd-bus/bus-control.h
@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "sd-bus.h"
+#include "forward.h"
 
 int bus_add_match_internal(sd_bus *bus, const char *match, uint64_t timeout_usec, uint64_t *ret_counter);
 int bus_add_match_internal_async(sd_bus *bus, sd_bus_slot **ret, const char *match, sd_bus_message_handler_t callback, void *userdata, uint64_t timeout_usec);
diff --git a/src/libsystemd/sd-bus/bus-convenience.c b/src/libsystemd/sd-bus/bus-convenience.c
index b59338a5d1..034ee49f00 100644
--- a/src/libsystemd/sd-bus/bus-convenience.c
+++ b/src/libsystemd/sd-bus/bus-convenience.c
@@ -1,14 +1,13 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <sys/types.h>
 #include <unistd.h>
 
-#include "alloc-util.h"
+#include "sd-bus.h"
+
 #include "bus-internal.h"
 #include "bus-message.h"
 #include "bus-signature.h"
 #include "bus-type.h"
-#include "log.h"
 #include "string-util.h"
 
 _public_ int sd_bus_message_send(sd_bus_message *reply) {
diff --git a/src/libsystemd/sd-bus/bus-creds.c b/src/libsystemd/sd-bus/bus-creds.c
index 9e93712bfd..700e7d24a9 100644
--- a/src/libsystemd/sd-bus/bus-creds.c
+++ b/src/libsystemd/sd-bus/bus-creds.c
@@ -1,7 +1,8 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <linux/capability.h>
-#include <stdlib.h>
+
+#include "sd-bus.h"
 
 #include "alloc-util.h"
 #include "audit-util.h"
@@ -17,6 +18,7 @@
 #include "hexdecoct.h"
 #include "nulstr-util.h"
 #include "parse-util.h"
+#include "pidref.h"
 #include "process-util.h"
 #include "string-util.h"
 #include "strv.h"
diff --git a/src/libsystemd/sd-bus/bus-creds.h b/src/libsystemd/sd-bus/bus-creds.h
index d7ad1dc96b..089442e885 100644
--- a/src/libsystemd/sd-bus/bus-creds.h
+++ b/src/libsystemd/sd-bus/bus-creds.h
@@ -1,14 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
+#include "forward.h"
 
-#include "sd-bus.h"
-
-#include "pidref.h"
-#include "user-util.h"
-
-struct sd_bus_creds {
+typedef struct sd_bus_creds {
         bool allocated;
         unsigned n_ref;
 
@@ -65,7 +60,7 @@ struct sd_bus_creds {
         char *cgroup_root;
 
         char *description, *unescaped_description;
-};
+} sd_bus_creds;
 
 #define SD_BUS_CREDS_INIT_FIELDS        \
         .uid = UID_INVALID,             \
diff --git a/src/libsystemd/sd-bus/bus-dump-json.c b/src/libsystemd/sd-bus/bus-dump-json.c
index d753f50a0c..b6fc5f598f 100644
--- a/src/libsystemd/sd-bus/bus-dump-json.c
+++ b/src/libsystemd/sd-bus/bus-dump-json.c
@@ -6,8 +6,7 @@
 #include "bus-internal.h"
 #include "bus-message.h"
 #include "json-util.h"
-#include "macro.h"
-#include "memory-util.h"
+#include "string-util.h"
 #include "time-util.h"
 
 static int json_transform_one(sd_bus_message *m, sd_json_variant **ret);
diff --git a/src/libsystemd/sd-bus/bus-dump.c b/src/libsystemd/sd-bus/bus-dump.c
index 07df7d7d34..d71274968c 100644
--- a/src/libsystemd/sd-bus/bus-dump.c
+++ b/src/libsystemd/sd-bus/bus-dump.c
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <sys/time.h>
+#include "sd-bus.h"
 
 #include "alloc-util.h"
 #include "ansi-color.h"
@@ -14,11 +14,10 @@
 #include "format-util.h"
 #include "glyph-util.h"
 #include "log.h"
-#include "macro.h"
 #include "pcapng.h"
 #include "string-util.h"
 #include "strv.h"
-#include "terminal-util.h"
+#include "time-util.h"
 
 static char* indent(unsigned level, uint64_t flags) {
         if (FLAGS_SET(flags, SD_BUS_MESSAGE_DUMP_SUBTREE_ONLY) && level > 0)
diff --git a/src/libsystemd/sd-bus/bus-dump.h b/src/libsystemd/sd-bus/bus-dump.h
index e7470ba681..ba38da1686 100644
--- a/src/libsystemd/sd-bus/bus-dump.h
+++ b/src/libsystemd/sd-bus/bus-dump.h
@@ -1,10 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
-#include <stdio.h>
-
-#include "sd-bus.h"
+#include "forward.h"
 
 int bus_creds_dump(sd_bus_creds *c, FILE *f, bool terse);
 
diff --git a/src/libsystemd/sd-bus/bus-error.c b/src/libsystemd/sd-bus/bus-error.c
index 9b812dd36c..b61df06632 100644
--- a/src/libsystemd/sd-bus/bus-error.c
+++ b/src/libsystemd/sd-bus/bus-error.c
@@ -1,20 +1,12 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
-#include <stdarg.h>
-#include <stdbool.h>
-#include <stdio.h>
-#include <stdlib.h>
-
 #include "sd-bus.h"
 
 #include "alloc-util.h"
 #include "bus-error.h"
 #include "errno-list.h"
 #include "errno-util.h"
-#include "log.h"
 #include "string-util.h"
-#include "strv.h"
 
 BUS_ERROR_MAP_ELF_REGISTER const sd_bus_error_map bus_standard_errors[] = {
         SD_BUS_ERROR_MAP(SD_BUS_ERROR_FAILED,                             EACCES),
@@ -592,7 +584,7 @@ const char* _bus_error_message(const sd_bus_error *e, int error, char buf[static
         if (e && e->message)
                 return e->message;
 
-        return strerror_r(abs(error), buf, ERRNO_BUF_LEN);
+        return strerror_r(ABS(error), buf, ERRNO_BUF_LEN);
 }
 
 static bool map_ok(const sd_bus_error_map *map) {
diff --git a/src/libsystemd/sd-bus/bus-error.h b/src/libsystemd/sd-bus/bus-error.h
index c8768c9a7b..3757fe7c27 100644
--- a/src/libsystemd/sd-bus/bus-error.h
+++ b/src/libsystemd/sd-bus/bus-error.h
@@ -1,12 +1,10 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
-
-#include "sd-bus.h"
+#include "sd-bus-protocol.h"
 
 #include "errno-util.h"
-#include "macro.h"
+#include "forward.h"
 
 bool bus_error_is_dirty(sd_bus_error *e);
 
diff --git a/src/libsystemd/sd-bus/bus-internal.c b/src/libsystemd/sd-bus/bus-internal.c
index 6a448c797f..ffb99bd824 100644
--- a/src/libsystemd/sd-bus/bus-internal.c
+++ b/src/libsystemd/sd-bus/bus-internal.c
@@ -1,6 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include "sd-bus.h"
+
 #include "alloc-util.h"
+#include "bus-error.h"
 #include "bus-internal.h"
 #include "bus-message.h"
 #include "escape.h"
diff --git a/src/libsystemd/sd-bus/bus-internal.h b/src/libsystemd/sd-bus/bus-internal.h
index 25fe4bd956..e9052b76b3 100644
--- a/src/libsystemd/sd-bus/bus-internal.h
+++ b/src/libsystemd/sd-bus/bus-internal.h
@@ -1,20 +1,15 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <pthread.h>
+#include "sd-id128.h"
 
-#include "sd-bus.h"
-
-#include "bus-error.h"
 #include "bus-kernel.h"
 #include "bus-match.h"
 #include "constants.h"
-#include "hashmap.h"
+#include "forward.h"
 #include "list.h"
-#include "prioq.h"
 #include "runtime-scope.h"
 #include "socket-util.h"
-#include "time-util.h"
 
 /* Note that we use the new /run prefix here (instead of /var/run) since we require them to be aliases and
  * that way we become independent of /var being mounted */
@@ -126,7 +121,7 @@ typedef enum BusSlotType {
         _BUS_SLOT_INVALID = -EINVAL,
 } BusSlotType;
 
-struct sd_bus_slot {
+typedef struct sd_bus_slot {
         unsigned n_ref;
         BusSlotType type:8;
 
@@ -157,7 +152,7 @@ struct sd_bus_slot {
                 struct node_object_manager node_object_manager;
                 struct node_vtable node_vtable;
         };
-};
+} sd_bus_slot;
 
 enum bus_state {
         BUS_UNSET,
@@ -181,7 +176,7 @@ enum bus_auth {
         BUS_AUTH_ANONYMOUS
 };
 
-struct sd_bus {
+typedef struct sd_bus {
         unsigned n_ref;
 
         enum bus_state state;
@@ -327,7 +322,7 @@ struct sd_bus {
 
         /* zero means use value specified by $SYSTEMD_BUS_TIMEOUT= environment variable or built-in default */
         usec_t method_call_timeout;
-};
+} sd_bus;
 
 /* For method calls we timeout at 25s, like in the D-Bus reference implementation */
 #define BUS_DEFAULT_TIMEOUT ((usec_t) (25 * USEC_PER_SEC))
diff --git a/src/libsystemd/sd-bus/bus-introspect.c b/src/libsystemd/sd-bus/bus-introspect.c
index 4c3914ff96..2bbc932939 100644
--- a/src/libsystemd/sd-bus/bus-introspect.c
+++ b/src/libsystemd/sd-bus/bus-introspect.c
@@ -1,15 +1,15 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <stdio.h>
+
+#include "sd-bus-vtable.h"
+
 #include "bus-internal.h"
 #include "bus-introspect.h"
 #include "bus-objects.h"
-#include "bus-protocol.h"
 #include "bus-signature.h"
-#include "fd-util.h"
-#include "fileio.h"
-#include "log.h"
-#include "memory-util.h"
 #include "memstream-util.h"
+#include "ordered-set.h"
 #include "string-util.h"
 
 #define BUS_INTROSPECT_DOCTYPE                                       \
diff --git a/src/libsystemd/sd-bus/bus-introspect.h b/src/libsystemd/sd-bus/bus-introspect.h
index 83bcfb2dad..f9d87c499b 100644
--- a/src/libsystemd/sd-bus/bus-introspect.h
+++ b/src/libsystemd/sd-bus/bus-introspect.h
@@ -1,12 +1,8 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdio.h>
-
-#include "sd-bus.h"
-
+#include "forward.h"
 #include "memstream-util.h"
-#include "ordered-set.h"
 
 struct introspect {
         MemStream m;
diff --git a/src/libsystemd/sd-bus/bus-kernel.c b/src/libsystemd/sd-bus/bus-kernel.c
index b726957c76..90fc60afbd 100644
--- a/src/libsystemd/sd-bus/bus-kernel.c
+++ b/src/libsystemd/sd-bus/bus-kernel.c
@@ -1,31 +1,11 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#if HAVE_VALGRIND_MEMCHECK_H
-#include <valgrind/memcheck.h>
-#endif
-
-#include <fcntl.h>
-#include <malloc.h>
 #include <sys/mman.h>
-#include <sys/prctl.h>
 
-#include "alloc-util.h"
-#include "bus-internal.h"
 #include "bus-kernel.h"
-#include "bus-label.h"
-#include "bus-message.h"
-#include "capability-util.h"
+#include "bus-internal.h"
 #include "fd-util.h"
-#include "fileio.h"
-#include "format-util.h"
-#include "log.h"
-#include "memfd-util.h"
 #include "memory-util.h"
-#include "parse-util.h"
-#include "stdio-util.h"
-#include "string-util.h"
-#include "strv.h"
-#include "user-util.h"
 
 void close_and_munmap(int fd, void *address, size_t size) {
         if (size > 0) {
diff --git a/src/libsystemd/sd-bus/bus-kernel.h b/src/libsystemd/sd-bus/bus-kernel.h
index be8e0ceb9b..c364f62a8d 100644
--- a/src/libsystemd/sd-bus/bus-kernel.h
+++ b/src/libsystemd/sd-bus/bus-kernel.h
@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "sd-bus.h"
+#include "forward.h"
 
 #define MEMFD_CACHE_MAX 32
 
diff --git a/src/libsystemd/sd-bus/bus-match.c b/src/libsystemd/sd-bus/bus-match.c
index a07d9d0521..fc05f385e8 100644
--- a/src/libsystemd/sd-bus/bus-match.c
+++ b/src/libsystemd/sd-bus/bus-match.c
@@ -1,15 +1,16 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include "sd-bus.h"
+
 #include "alloc-util.h"
 #include "bus-internal.h"
 #include "bus-match.h"
 #include "bus-message.h"
-#include "fd-util.h"
-#include "fileio.h"
+#include "hashmap.h"
 #include "hexdecoct.h"
-#include "log.h"
 #include "memstream-util.h"
 #include "sort-util.h"
+#include "stdio-util.h"
 #include "string-util.h"
 #include "strv.h"
 
diff --git a/src/libsystemd/sd-bus/bus-match.h b/src/libsystemd/sd-bus/bus-match.h
index 138123c70b..622e00d94c 100644
--- a/src/libsystemd/sd-bus/bus-match.h
+++ b/src/libsystemd/sd-bus/bus-match.h
@@ -1,11 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdio.h>
-
-#include "sd-bus.h"
-
-#include "hashmap.h"
+#include "forward.h"
 
 enum bus_match_node_type {
         BUS_MATCH_ROOT,
diff --git a/src/libsystemd/sd-bus/bus-message.c b/src/libsystemd/sd-bus/bus-message.c
index 8eff8781ab..6636285526 100644
--- a/src/libsystemd/sd-bus/bus-message.c
+++ b/src/libsystemd/sd-bus/bus-message.c
@@ -1,7 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
-#include <fcntl.h>
 #include <sys/mman.h>
 
 #include "sd-bus.h"
@@ -18,7 +16,6 @@
 #include "memory-util.h"
 #include "string-util.h"
 #include "strv.h"
-#include "time-util.h"
 #include "utf8.h"
 
 static int message_append_basic(sd_bus_message *m, char type, const void *p, const void **stored);
diff --git a/src/libsystemd/sd-bus/bus-message.h b/src/libsystemd/sd-bus/bus-message.h
index 76f0d853d3..0f1cc8f33e 100644
--- a/src/libsystemd/sd-bus/bus-message.h
+++ b/src/libsystemd/sd-bus/bus-message.h
@@ -2,15 +2,14 @@
 #pragma once
 
 #include <byteswap.h>
-#include <stdbool.h>
-#include <sys/socket.h>
+#include <sys/uio.h>
 
-#include "sd-bus.h"
+#include "sd-bus-protocol.h"
 
 #include "bus-creds.h"
 #include "bus-protocol.h"
-#include "macro.h"
-#include "time-util.h"
+#include "forward.h"
+#include "memory-util.h"
 
 struct bus_container {
         char enclosing;
@@ -42,7 +41,7 @@ struct bus_body_part {
         bool is_zero:1;
 };
 
-struct sd_bus_message {
+typedef struct sd_bus_message {
         /* Caveat: a message can be referenced in two different ways: the main (user-facing) way will also
          * pin the bus connection object the message is associated with. The secondary way ("queued") is used
          * when a message is in the read or write queues of the bus connection object, which will not pin the
@@ -119,7 +118,7 @@ struct sd_bus_message {
         unsigned n_header_offsets;
 
         uint64_t read_counter;
-};
+} sd_bus_message;
 
 static inline bool BUS_MESSAGE_NEED_BSWAP(sd_bus_message *m) {
         return m->header->endian != BUS_NATIVE_ENDIAN;
diff --git a/src/libsystemd/sd-bus/bus-objects.c b/src/libsystemd/sd-bus/bus-objects.c
index e7ec43a19d..3e827770c8 100644
--- a/src/libsystemd/sd-bus/bus-objects.c
+++ b/src/libsystemd/sd-bus/bus-objects.c
@@ -2,6 +2,8 @@
 
 #include <linux/capability.h>
 
+#include "sd-bus.h"
+
 #include "alloc-util.h"
 #include "bus-internal.h"
 #include "bus-introspect.h"
@@ -10,7 +12,7 @@
 #include "bus-signature.h"
 #include "bus-slot.h"
 #include "bus-type.h"
-#include "log.h"
+#include "ordered-set.h"
 #include "set.h"
 #include "string-util.h"
 #include "strv.h"
diff --git a/src/libsystemd/sd-bus/bus-objects.h b/src/libsystemd/sd-bus/bus-objects.h
index 20fccfa1d8..51bfa70ae5 100644
--- a/src/libsystemd/sd-bus/bus-objects.h
+++ b/src/libsystemd/sd-bus/bus-objects.h
@@ -1,8 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "bus-internal.h"
-#include "bus-introspect.h"
+#include "forward.h"
+
+struct node;
 
 const sd_bus_vtable* bus_vtable_next(const sd_bus_vtable *vtable, const sd_bus_vtable *v);
 bool bus_vtable_has_names(const sd_bus_vtable *vtable);
diff --git a/src/libsystemd/sd-bus/bus-protocol.h b/src/libsystemd/sd-bus/bus-protocol.h
index be46b5f6a7..92e251727c 100644
--- a/src/libsystemd/sd-bus/bus-protocol.h
+++ b/src/libsystemd/sd-bus/bus-protocol.h
@@ -3,7 +3,7 @@
 
 #include <endian.h>
 
-#include "macro.h"
+#include "forward.h"
 
 /* Packet header */
 
diff --git a/src/libsystemd/sd-bus/bus-signature.c b/src/libsystemd/sd-bus/bus-signature.c
index 16693bcad6..d2f202067b 100644
--- a/src/libsystemd/sd-bus/bus-signature.c
+++ b/src/libsystemd/sd-bus/bus-signature.c
@@ -1,8 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include "sd-bus.h"
+#include "sd-bus-protocol.h"
 
-#include "assert-util.h"
 #include "bus-signature.h"
 #include "bus-type.h"
 
diff --git a/src/libsystemd/sd-bus/bus-signature.h b/src/libsystemd/sd-bus/bus-signature.h
index 0fea750744..b75df7335d 100644
--- a/src/libsystemd/sd-bus/bus-signature.h
+++ b/src/libsystemd/sd-bus/bus-signature.h
@@ -1,8 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
-#include <stddef.h>
+#include "forward.h"
 
 bool signature_is_single(const char *s, bool allow_dict_entry);
 bool signature_is_pair(const char *s);
diff --git a/src/libsystemd/sd-bus/bus-slot.c b/src/libsystemd/sd-bus/bus-slot.c
index ed9da96638..3b6debadb0 100644
--- a/src/libsystemd/sd-bus/bus-slot.c
+++ b/src/libsystemd/sd-bus/bus-slot.c
@@ -6,7 +6,7 @@
 #include "bus-control.h"
 #include "bus-objects.h"
 #include "bus-slot.h"
-#include "log.h"
+#include "prioq.h"
 #include "set.h"
 #include "string-util.h"
 
diff --git a/src/libsystemd/sd-bus/bus-slot.h b/src/libsystemd/sd-bus/bus-slot.h
index 8116195d4d..5bd3b081ea 100644
--- a/src/libsystemd/sd-bus/bus-slot.h
+++ b/src/libsystemd/sd-bus/bus-slot.h
@@ -1,9 +1,8 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "sd-bus.h"
-
 #include "bus-internal.h"
+#include "forward.h"
 
 sd_bus_slot *bus_slot_allocate(sd_bus *bus, bool floating, BusSlotType type, size_t extra, void *userdata);
 
diff --git a/src/libsystemd/sd-bus/bus-socket.c b/src/libsystemd/sd-bus/bus-socket.c
index 7271c68971..9d911aaaa6 100644
--- a/src/libsystemd/sd-bus/bus-socket.c
+++ b/src/libsystemd/sd-bus/bus-socket.c
@@ -1,8 +1,10 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <endian.h>
+#include <grp.h>
 #include <poll.h>
 #include <stdlib.h>
+#include <sys/inotify.h>
 #include <unistd.h>
 
 #include "sd-bus.h"
@@ -12,22 +14,21 @@
 #include "bus-internal.h"
 #include "bus-message.h"
 #include "bus-socket.h"
+#include "errno-util.h"
 #include "escape.h"
 #include "fd-util.h"
-#include "format-util.h"
 #include "fs-util.h"
 #include "hexdecoct.h"
 #include "io-util.h"
 #include "iovec-util.h"
 #include "log.h"
-#include "macro.h"
 #include "memory-util.h"
 #include "path-util.h"
 #include "process-util.h"
 #include "random-util.h"
-#include "signal-util.h"
 #include "stdio-util.h"
 #include "string-util.h"
+#include "time-util.h"
 #include "user-util.h"
 #include "utf8.h"
 
diff --git a/src/libsystemd/sd-bus/bus-socket.h b/src/libsystemd/sd-bus/bus-socket.h
index fc8c1eda09..1c1d3561ee 100644
--- a/src/libsystemd/sd-bus/bus-socket.h
+++ b/src/libsystemd/sd-bus/bus-socket.h
@@ -1,9 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
-
-#include "sd-bus.h"
+#include "forward.h"
 
 void bus_socket_setup(sd_bus *b);
 
diff --git a/src/libsystemd/sd-bus/bus-track.c b/src/libsystemd/sd-bus/bus-track.c
index 3c3e0c18ec..9e5b5e9620 100644
--- a/src/libsystemd/sd-bus/bus-track.c
+++ b/src/libsystemd/sd-bus/bus-track.c
@@ -5,6 +5,7 @@
 #include "alloc-util.h"
 #include "bus-internal.h"
 #include "bus-track.h"
+#include "hashmap.h"
 #include "log.h"
 #include "string-util.h"
 
diff --git a/src/libsystemd/sd-bus/bus-track.h b/src/libsystemd/sd-bus/bus-track.h
index 6868cda1e2..0ecd42e6d3 100644
--- a/src/libsystemd/sd-bus/bus-track.h
+++ b/src/libsystemd/sd-bus/bus-track.h
@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-typedef struct sd_bus_track sd_bus_track;
+#include "forward.h"
 
 void bus_track_dispatch(sd_bus_track *track);
 void bus_track_close(sd_bus_track *track);
diff --git a/src/libsystemd/sd-bus/bus-type.c b/src/libsystemd/sd-bus/bus-type.c
index d1fc836dde..91b76b4c02 100644
--- a/src/libsystemd/sd-bus/bus-type.c
+++ b/src/libsystemd/sd-bus/bus-type.c
@@ -1,12 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
-
 #include "sd-bus.h"
 
 #include "bus-internal.h"
 #include "bus-type.h"
-#include "log.h"
 
 bool bus_type_is_valid(char c) {
         static const char valid[] = {
diff --git a/src/libsystemd/sd-bus/bus-type.h b/src/libsystemd/sd-bus/bus-type.h
index 490108a2c6..0e851b0249 100644
--- a/src/libsystemd/sd-bus/bus-type.h
+++ b/src/libsystemd/sd-bus/bus-type.h
@@ -1,9 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
-
-#include "macro.h"
+#include "forward.h"
 
 bool bus_type_is_valid(char c) _const_;
 bool bus_type_is_basic(char c) _const_;
diff --git a/src/libsystemd/sd-bus/fuzz-bus-match.c b/src/libsystemd/sd-bus/fuzz-bus-match.c
index 16da534245..e6e3dd97d0 100644
--- a/src/libsystemd/sd-bus/fuzz-bus-match.c
+++ b/src/libsystemd/sd-bus/fuzz-bus-match.c
@@ -1,11 +1,11 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include "sd-bus.h"
+
 #include "alloc-util.h"
 #include "bus-internal.h"
 #include "bus-match.h"
 #include "env-util.h"
-#include "fd-util.h"
-#include "fileio.h"
 #include "fuzz.h"
 #include "memstream-util.h"
 
diff --git a/src/libsystemd/sd-bus/fuzz-bus-message.c b/src/libsystemd/sd-bus/fuzz-bus-message.c
index e369f532c9..e2c4167f3c 100644
--- a/src/libsystemd/sd-bus/fuzz-bus-message.c
+++ b/src/libsystemd/sd-bus/fuzz-bus-message.c
@@ -1,11 +1,10 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include "sd-bus.h"
+
 #include "alloc-util.h"
-#include "bus-dump.h"
 #include "bus-message.h"
 #include "env-util.h"
-#include "fd-util.h"
-#include "fileio.h"
 #include "fuzz.h"
 #include "memstream-util.h"
 
diff --git a/src/libsystemd/sd-bus/sd-bus.c b/src/libsystemd/sd-bus/sd-bus.c
index b0d0b0e1d1..c13a898212 100644
--- a/src/libsystemd/sd-bus/sd-bus.c
+++ b/src/libsystemd/sd-bus/sd-bus.c
@@ -1,22 +1,21 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <endian.h>
 #include <netdb.h>
+#include <poll.h>
 #include <pthread.h>
-#include <signal.h>
 #include <stdlib.h>
-#include <sys/mman.h>
 #include <sys/stat.h>
-#include <sys/wait.h>
 #include <threads.h>
 #include <unistd.h>
 
 #include "sd-bus.h"
+#include "sd-event.h"
 
 #include "af-list.h"
 #include "alloc-util.h"
 #include "bus-container.h"
 #include "bus-control.h"
+#include "bus-error.h"
 #include "bus-internal.h"
 #include "bus-kernel.h"
 #include "bus-label.h"
@@ -28,7 +27,6 @@
 #include "bus-track.h"
 #include "bus-type.h"
 #include "cgroup-util.h"
-#include "constants.h"
 #include "errno-util.h"
 #include "fd-util.h"
 #include "format-util.h"
@@ -38,16 +36,16 @@
 #include "io-util.h"
 #include "log.h"
 #include "log-context.h"
-#include "macro.h"
 #include "memory-util.h"
-#include "missing_syscall.h"
 #include "origin-id.h"
 #include "parse-util.h"
 #include "path-util.h"
+#include "prioq.h"
 #include "process-util.h"
-#include "stdio-util.h"
+#include "set.h"
 #include "string-util.h"
 #include "strv.h"
+#include "time-util.h"
 #include "user-util.h"
 
 #define log_debug_bus_message(m)                                         \
diff --git a/src/libsystemd/sd-bus/test-bus-benchmark.c b/src/libsystemd/sd-bus/test-bus-benchmark.c
index 78ae564aeb..4063d79159 100644
--- a/src/libsystemd/sd-bus/test-bus-benchmark.c
+++ b/src/libsystemd/sd-bus/test-bus-benchmark.c
@@ -1,5 +1,8 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <pthread.h>
+#include <sched.h>
+#include <stdlib.h>
 #include <sys/resource.h>
 #include <sys/wait.h>
 #include <unistd.h>
@@ -8,10 +11,7 @@
 
 #include "alloc-util.h"
 #include "bus-internal.h"
-#include "bus-kernel.h"
-#include "constants.h"
 #include "fd-util.h"
-#include "string-util.h"
 #include "tests.h"
 #include "time-util.h"
 
diff --git a/src/libsystemd/sd-bus/test-bus-chat.c b/src/libsystemd/sd-bus/test-bus-chat.c
index d06853b22c..df1be5ceca 100644
--- a/src/libsystemd/sd-bus/test-bus-chat.c
+++ b/src/libsystemd/sd-bus/test-bus-chat.c
@@ -2,7 +2,6 @@
 
 #include <fcntl.h>
 #include <pthread.h>
-#include <stdlib.h>
 #include <unistd.h>
 
 #include "sd-bus.h"
@@ -15,9 +14,9 @@
 #include "fd-util.h"
 #include "format-util.h"
 #include "log.h"
-#include "macro.h"
 #include "string-util.h"
 #include "tests.h"
+#include "time-util.h"
 
 static int match_callback(sd_bus_message *m, void *userdata, sd_bus_error *ret_error) {
         log_info("Match triggered! destination=%s interface=%s member=%s",
diff --git a/src/libsystemd/sd-bus/test-bus-cleanup.c b/src/libsystemd/sd-bus/test-bus-cleanup.c
index b569986a94..7c9899e129 100644
--- a/src/libsystemd/sd-bus/test-bus-cleanup.c
+++ b/src/libsystemd/sd-bus/test-bus-cleanup.c
@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <stdio.h>
 #include <unistd.h>
 
 #include "sd-bus.h"
diff --git a/src/libsystemd/sd-bus/test-bus-marshal.c b/src/libsystemd/sd-bus/test-bus-marshal.c
index 31b04002b5..d52683ea87 100644
--- a/src/libsystemd/sd-bus/test-bus-marshal.c
+++ b/src/libsystemd/sd-bus/test-bus-marshal.c
@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <math.h>
-#include <stdlib.h>
 
 /* We make an exception here to our usual "include system headers first" rule because we need one of these
  * macros to disable a warning triggered by the glib headers. */
@@ -20,13 +19,10 @@ REENABLE_WARNING
 #include "sd-bus.h"
 
 #include "alloc-util.h"
-#include "bus-dump.h"
 #include "bus-label.h"
 #include "bus-message.h"
 #include "bus-util.h"
 #include "escape.h"
-#include "fd-util.h"
-#include "fileio.h"
 #include "log.h"
 #include "memstream-util.h"
 #include "tests.h"
diff --git a/src/libsystemd/sd-bus/test-bus-match.c b/src/libsystemd/sd-bus/test-bus-match.c
index 2d7755711e..7b212c8eaa 100644
--- a/src/libsystemd/sd-bus/test-bus-match.c
+++ b/src/libsystemd/sd-bus/test-bus-match.c
@@ -1,10 +1,11 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include "sd-bus.h"
+
+#include "bus-internal.h"
 #include "bus-match.h"
 #include "bus-message.h"
-#include "bus-slot.h"
 #include "log.h"
-#include "macro.h"
 #include "memory-util.h"
 #include "tests.h"
 
diff --git a/src/libsystemd/sd-bus/test-bus-objects.c b/src/libsystemd/sd-bus/test-bus-objects.c
index c9ec474856..fac3e15085 100644
--- a/src/libsystemd/sd-bus/test-bus-objects.c
+++ b/src/libsystemd/sd-bus/test-bus-objects.c
@@ -1,16 +1,13 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <pthread.h>
-#include <stdlib.h>
 
 #include "sd-bus.h"
 
 #include "alloc-util.h"
-#include "bus-dump.h"
 #include "bus-internal.h"
 #include "bus-message.h"
 #include "log.h"
-#include "macro.h"
 #include "strv.h"
 #include "tests.h"
 
diff --git a/src/libsystemd/sd-bus/test-bus-peersockaddr.c b/src/libsystemd/sd-bus/test-bus-peersockaddr.c
index 8b11a7af33..32072097ba 100644
--- a/src/libsystemd/sd-bus/test-bus-peersockaddr.c
+++ b/src/libsystemd/sd-bus/test-bus-peersockaddr.c
@@ -6,11 +6,10 @@
 #include "sd-bus.h"
 
 #include "bus-dump.h"
-#include "bus-util.h"
 #include "fd-util.h"
+#include "pidref.h"
 #include "process-util.h"
 #include "socket-util.h"
-#include "sort-util.h"
 #include "tests.h"
 #include "user-util.h"
 
diff --git a/src/libsystemd/sd-bus/test-bus-queue-ref-cycle.c b/src/libsystemd/sd-bus/test-bus-queue-ref-cycle.c
index 7c2fa72e84..debe78c7e2 100644
--- a/src/libsystemd/sd-bus/test-bus-queue-ref-cycle.c
+++ b/src/libsystemd/sd-bus/test-bus-queue-ref-cycle.c
@@ -1,4 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
+
 #include "sd-bus.h"
 
 #include "main-func.h"
diff --git a/src/libsystemd/sd-bus/test-bus-server.c b/src/libsystemd/sd-bus/test-bus-server.c
index 8049e33294..68f5e00040 100644
--- a/src/libsystemd/sd-bus/test-bus-server.c
+++ b/src/libsystemd/sd-bus/test-bus-server.c
@@ -1,13 +1,12 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <pthread.h>
-#include <stdlib.h>
+#include <sys/socket.h>
 
 #include "sd-bus.h"
 
-#include "bus-internal.h"
+#include "bus-error.h"
 #include "log.h"
-#include "macro.h"
 #include "memory-util.h"
 #include "string-util.h"
 #include "tests.h"
diff --git a/src/libsystemd/sd-bus/test-bus-signature.c b/src/libsystemd/sd-bus/test-bus-signature.c
index 5a4c811864..2417208281 100644
--- a/src/libsystemd/sd-bus/test-bus-signature.c
+++ b/src/libsystemd/sd-bus/test-bus-signature.c
@@ -3,7 +3,6 @@
 #include "bus-internal.h"
 #include "bus-signature.h"
 #include "log.h"
-#include "string-util.h"
 #include "tests.h"
 
 int main(int argc, char *argv[]) {
diff --git a/src/libsystemd/sd-bus/test-bus-track.c b/src/libsystemd/sd-bus/test-bus-track.c
index 5604e84f52..4f14787f30 100644
--- a/src/libsystemd/sd-bus/test-bus-track.c
+++ b/src/libsystemd/sd-bus/test-bus-track.c
@@ -1,11 +1,10 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
 #include <sys/socket.h>
 
 #include "sd-bus.h"
+#include "sd-event.h"
 
-#include "macro.h"
 #include "tests.h"
 
 static bool track_cb_called_x = false;
diff --git a/src/libsystemd/sd-bus/test-bus-vtable.c b/src/libsystemd/sd-bus/test-bus-vtable.c
index bc6be901ad..17cd1bb51c 100644
--- a/src/libsystemd/sd-bus/test-bus-vtable.c
+++ b/src/libsystemd/sd-bus/test-bus-vtable.c
@@ -1,18 +1,15 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <stdbool.h>
-#include <stddef.h>
-
 /* We use system assert.h here, because we don't want to keep macro.h and log.h C++ compatible */
 #undef NDEBUG
 #include <assert.h>
-#include <errno.h>
 #include <stdio.h>
 
 #include "sd-bus.h"
 #include "sd-bus-vtable.h"
 
 #ifndef __cplusplus
+#  include "alloc-util.h"
 #  include "bus-objects.h"
 #  include "log.h"
 #endif
diff --git a/src/libsystemd/sd-bus/test-bus-watch-bind.c b/src/libsystemd/sd-bus/test-bus-watch-bind.c
index f7ba14a6a8..c6c072440e 100644
--- a/src/libsystemd/sd-bus/test-bus-watch-bind.c
+++ b/src/libsystemd/sd-bus/test-bus-watch-bind.c
@@ -17,6 +17,7 @@
 #include "socket-util.h"
 #include "string-util.h"
 #include "tests.h"
+#include "time-util.h"
 #include "tmpfile-util.h"
 
 static int method_foobar(sd_bus_message *m, void *userdata, sd_bus_error *ret_error) {
diff --git a/src/libsystemd/sd-daemon/sd-daemon.c b/src/libsystemd/sd-daemon/sd-daemon.c
index b7635a60b6..14733d0f17 100644
--- a/src/libsystemd/sd-daemon/sd-daemon.c
+++ b/src/libsystemd/sd-daemon/sd-daemon.c
@@ -1,14 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
-#include <limits.h>
 #include <mqueue.h>
 #include <netinet/in.h>
 #include <poll.h>
-#include <stdarg.h>
-#include <stddef.h>
 #include <stdio.h>
-#include <stdlib.h>
 #include <sys/stat.h>
 #include <sys/un.h>
 #include <unistd.h>
@@ -16,6 +11,7 @@
 #include "sd-daemon.h"
 
 #include "alloc-util.h"
+#include "errno-util.h"
 #include "extract-word.h"
 #include "fd-util.h"
 #include "fs-util.h"
diff --git a/src/libsystemd/sd-device/device-enumerator-private.h b/src/libsystemd/sd-device/device-enumerator-private.h
index cf62fabdad..f4b836e16a 100644
--- a/src/libsystemd/sd-device/device-enumerator-private.h
+++ b/src/libsystemd/sd-device/device-enumerator-private.h
@@ -1,9 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
-
-#include "sd-device.h"
+#include "forward.h"
 
 typedef enum MatchInitializedType {
         MATCH_INITIALIZED_NO,     /* only devices without a db entry */
diff --git a/src/libsystemd/sd-device/device-enumerator.c b/src/libsystemd/sd-device/device-enumerator.c
index 8230763ddd..1b2b534530 100644
--- a/src/libsystemd/sd-device/device-enumerator.c
+++ b/src/libsystemd/sd-device/device-enumerator.c
@@ -1,8 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <fcntl.h>
 #include <fnmatch.h>
-#include <unistd.h>
 
 #include "sd-device.h"
 
@@ -12,6 +10,8 @@
 #include "device-util.h"
 #include "dirent-util.h"
 #include "fd-util.h"
+#include "log.h"
+#include "path-util.h"
 #include "set.h"
 #include "sort-util.h"
 #include "string-util.h"
diff --git a/src/libsystemd/sd-device/device-filter.c b/src/libsystemd/sd-device/device-filter.c
index bf7d4d4be5..cffc91ce93 100644
--- a/src/libsystemd/sd-device/device-filter.c
+++ b/src/libsystemd/sd-device/device-filter.c
@@ -1,10 +1,12 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <fnmatch.h>
+#include "sd-device.h"
 
 #include "alloc-util.h"
 #include "device-filter.h"
+#include "hashmap.h"
 #include "path-util.h"
+#include "set.h"
 #include "strv.h"
 
 int update_match_strv(Hashmap **match_strv, const char *key, const char *value, bool clear_on_null) {
diff --git a/src/libsystemd/sd-device/device-filter.h b/src/libsystemd/sd-device/device-filter.h
index 0c5f34e242..d72cbab7e8 100644
--- a/src/libsystemd/sd-device/device-filter.h
+++ b/src/libsystemd/sd-device/device-filter.h
@@ -1,12 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
-
-#include "sd-device.h"
-
-#include "hashmap.h"
-#include "set.h"
+#include "forward.h"
 
 int update_match_strv(Hashmap **match_strv, const char *key, const char *value, bool clear_on_null);
 bool device_match_sysattr(sd_device *device, Hashmap *match_sysattr, Hashmap *nomatch_sysattr);
diff --git a/src/libsystemd/sd-device/device-internal.h b/src/libsystemd/sd-device/device-internal.h
index cbd89849bd..1f9cf59d51 100644
--- a/src/libsystemd/sd-device/device-internal.h
+++ b/src/libsystemd/sd-device/device-internal.h
@@ -3,10 +3,8 @@
 
 #include "sd-device.h"
 
-#include "device-private.h"
-#include "hashmap.h"
-#include "set.h"
-#include "time-util.h"
+#include "forward.h"
+#include "iterator.h"
 
 #define LATEST_UDEV_DATABASE_VERSION 1
 
diff --git a/src/libsystemd/sd-device/device-monitor-private.h b/src/libsystemd/sd-device/device-monitor-private.h
index 79f9d834ff..309d4979e2 100644
--- a/src/libsystemd/sd-device/device-monitor-private.h
+++ b/src/libsystemd/sd-device/device-monitor-private.h
@@ -1,11 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <errno.h>
-
-#include "sd-device.h"
-
-#include "socket-util.h"
+#include "forward.h"
 
 typedef enum MonitorNetlinkGroup {
         MONITOR_GROUP_NONE,
diff --git a/src/libsystemd/sd-device/device-monitor.c b/src/libsystemd/sd-device/device-monitor.c
index 99bdc7f342..5ae1eb6390 100644
--- a/src/libsystemd/sd-device/device-monitor.c
+++ b/src/libsystemd/sd-device/device-monitor.c
@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
 #include <linux/filter.h>
 #include <linux/netlink.h>
 #include <linux/sockios.h>
@@ -22,13 +21,13 @@
 #include "hashmap.h"
 #include "io-util.h"
 #include "iovec-util.h"
+#include "log.h"
 #include "log-context.h"
-#include "missing_socket.h"
 #include "mountpoint-util.h"
 #include "set.h"
+#include "socket-util.h"
 #include "stat-util.h"
 #include "string-util.h"
-#include "strv.h"
 #include "uid-range.h"
 
 #define log_monitor(m, format, ...)                                     \
diff --git a/src/libsystemd/sd-device/device-private.c b/src/libsystemd/sd-device/device-private.c
index 270e0293e1..9896e0e7ac 100644
--- a/src/libsystemd/sd-device/device-private.c
+++ b/src/libsystemd/sd-device/device-private.c
@@ -1,8 +1,8 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <ctype.h>
-#include <net/if.h>
-#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
+#include <unistd.h>
 
 #include "sd-device.h"
 
@@ -10,21 +10,21 @@
 #include "device-internal.h"
 #include "device-private.h"
 #include "device-util.h"
+#include "extract-word.h"
 #include "fd-util.h"
 #include "fileio.h"
 #include "fs-util.h"
 #include "hashmap.h"
-#include "macro.h"
 #include "mkdir.h"
 #include "nulstr-util.h"
 #include "parse-util.h"
 #include "path-util.h"
 #include "set.h"
-#include "stdio-util.h"
 #include "string-table.h"
 #include "string-util.h"
 #include "strv.h"
 #include "strxcpyx.h"
+#include "time-util.h"
 #include "tmpfile-util.h"
 #include "user-util.h"
 
diff --git a/src/libsystemd/sd-device/device-private.h b/src/libsystemd/sd-device/device-private.h
index 7d609d1a41..b5a24dde1c 100644
--- a/src/libsystemd/sd-device/device-private.h
+++ b/src/libsystemd/sd-device/device-private.h
@@ -1,16 +1,11 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <dirent.h>
-#include <inttypes.h>
-#include <stdbool.h>
-#include <sys/stat.h>
-#include <sys/types.h>
+#include "sd-device.h" /* IWYU pragma: export */
 
-#include "sd-device.h"
+#include "forward.h"
 
-#include "chase.h"
-#include "macro.h"
+typedef enum ChaseFlags ChaseFlags;
 
 int device_new_from_mode_and_devnum(sd_device **ret, mode_t mode, dev_t devnum);
 int device_new_from_nulstr(sd_device **ret, char *nulstr, size_t len);
diff --git a/src/libsystemd/sd-device/device-util.c b/src/libsystemd/sd-device/device-util.c
index 5169c24d84..718b703066 100644
--- a/src/libsystemd/sd-device/device-util.c
+++ b/src/libsystemd/sd-device/device-util.c
@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include "alloc-util.h"
 #include "device-private.h"
 #include "device-util.h"
 #include "devnum-util.h"
@@ -29,6 +28,11 @@ int devname_from_devnum(mode_t mode, dev_t devnum, char **ret) {
         return strdup_to(ret, devname);
 }
 
+int devname_from_stat_rdev(const struct stat *st, char **ret) {
+        assert(st);
+        return devname_from_devnum(st->st_mode, st->st_rdev, ret);
+}
+
 int device_open_from_devnum(mode_t mode, dev_t devnum, int flags, char **ret_devname) {
         _cleanup_(sd_device_unrefp) sd_device *dev = NULL;
         _cleanup_close_ int fd = -EBADF;
diff --git a/src/libsystemd/sd-device/device-util.h b/src/libsystemd/sd-device/device-util.h
index 5b899ecfcd..136d399d7e 100644
--- a/src/libsystemd/sd-device/device-util.h
+++ b/src/libsystemd/sd-device/device-util.h
@@ -1,15 +1,10 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-
 #include "sd-device.h"
 
-#include "alloc-util.h"
+#include "forward.h"
 #include "log.h"
-#include "macro.h"
 
 #define device_unref_and_replace(a, b)                                  \
         unref_and_replace_full(a, b, sd_device_ref, sd_device_unref)
@@ -95,10 +90,7 @@
 #define log_device_error_errno(device, error, ...)   log_device_full_errno(device, LOG_ERR,     error, __VA_ARGS__)
 
 int devname_from_devnum(mode_t mode, dev_t devnum, char **ret);
-static inline int devname_from_stat_rdev(const struct stat *st, char **ret) {
-        assert(st);
-        return devname_from_devnum(st->st_mode, st->st_rdev, ret);
-}
+int devname_from_stat_rdev(const struct stat *st, char **ret);
 int device_open_from_devnum(mode_t mode, dev_t devnum, int flags, char **ret_devname);
 
 char** device_make_log_fields(sd_device *device);
diff --git a/src/libsystemd/sd-device/sd-device.c b/src/libsystemd/sd-device/sd-device.c
index c90d267456..aef02350cc 100644
--- a/src/libsystemd/sd-device/sd-device.c
+++ b/src/libsystemd/sd-device/sd-device.c
@@ -1,11 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <ctype.h>
-#include <net/if.h>
-#include <sys/ioctl.h>
-#include <sys/types.h>
+#include <unistd.h>
 
 #include "sd-device.h"
+#include "sd-id128.h"
 
 #include "alloc-util.h"
 #include "chase.h"
@@ -15,24 +13,23 @@
 #include "devnum-util.h"
 #include "dirent-util.h"
 #include "env-util.h"
+#include "errno-util.h"
+#include "extract-word.h"
 #include "fd-util.h"
 #include "fileio.h"
-#include "format-util.h"
 #include "fs-util.h"
 #include "hashmap.h"
-#include "id128-util.h"
-#include "macro.h"
 #include "missing_magic.h"
 #include "netlink-util.h"
 #include "parse-util.h"
 #include "path-util.h"
 #include "set.h"
 #include "socket-util.h"
+#include "stat-util.h"
 #include "stdio-util.h"
 #include "string-util.h"
 #include "strv.h"
-#include "strxcpyx.h"
-#include "user-util.h"
+#include "time-util.h"
 
 int device_new_aux(sd_device **ret) {
         sd_device *device;
diff --git a/src/libsystemd/sd-device/test-device-util.c b/src/libsystemd/sd-device/test-device-util.c
index aa3fb8215f..030beff8b3 100644
--- a/src/libsystemd/sd-device/test-device-util.c
+++ b/src/libsystemd/sd-device/test-device-util.c
@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include "sd-device.h"
+
 #include "device-util.h"
 #include "mountpoint-util.h"
 #include "tests.h"
diff --git a/src/libsystemd/sd-device/test-sd-device-monitor.c b/src/libsystemd/sd-device/test-sd-device-monitor.c
index 362ce0a85e..c1c720b364 100644
--- a/src/libsystemd/sd-device/test-sd-device-monitor.c
+++ b/src/libsystemd/sd-device/test-sd-device-monitor.c
@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <stdbool.h>
 #include <unistd.h>
 
 #include "sd-device.h"
@@ -10,13 +9,13 @@
 #include "device-private.h"
 #include "device-util.h"
 #include "io-util.h"
-#include "macro.h"
 #include "mountpoint-util.h"
 #include "path-util.h"
+#include "socket-util.h"
 #include "stat-util.h"
 #include "string-util.h"
 #include "tests.h"
-#include "virt.h"
+#include "time-util.h"
 
 static void prepare_loopback(sd_device **ret) {
         _cleanup_(sd_device_unrefp) sd_device *dev = NULL;
diff --git a/src/libsystemd/sd-device/test-sd-device-thread.c b/src/libsystemd/sd-device/test-sd-device-thread.c
index 539dabd7a6..1738ddb620 100644
--- a/src/libsystemd/sd-device/test-sd-device-thread.c
+++ b/src/libsystemd/sd-device/test-sd-device-thread.c
@@ -1,9 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
 #include <pthread.h>
-#include <stdio.h>
-#include <stdlib.h>
 
 #include "sd-device.h"
 
@@ -12,7 +9,7 @@
 
 #define handle_error_errno(error, msg)                          \
         ({                                                      \
-                errno = abs(error);                             \
+                errno = ABS(error);                             \
                 perror(msg);                                    \
                 EXIT_FAILURE;                                   \
         })
diff --git a/src/libsystemd/sd-device/test-sd-device.c b/src/libsystemd/sd-device/test-sd-device.c
index ff59d3bd50..4173f76dd8 100644
--- a/src/libsystemd/sd-device/test-sd-device.c
+++ b/src/libsystemd/sd-device/test-sd-device.c
@@ -1,10 +1,10 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <ctype.h>
 #include <fcntl.h>
 #include <unistd.h>
 
-#include "device-enumerator-private.h"
+#include "sd-event.h"
+
 #include "device-internal.h"
 #include "device-private.h"
 #include "device-util.h"
@@ -15,10 +15,10 @@
 #include "nulstr-util.h"
 #include "path-util.h"
 #include "rm-rf.h"
+#include "set.h"
 #include "stat-util.h"
 #include "string-util.h"
 #include "tests.h"
-#include "time-util.h"
 #include "tmpfile-util.h"
 #include "udev-util.h"
 
diff --git a/src/libsystemd/sd-event/event-source.h b/src/libsystemd/sd-event/event-source.h
index d05bcf0538..3be9a0e6c1 100644
--- a/src/libsystemd/sd-event/event-source.h
+++ b/src/libsystemd/sd-event/event-source.h
@@ -1,16 +1,14 @@
-#pragma once
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
+#pragma once
 
-#include <sys/epoll.h>
-#include <sys/timerfd.h>
-#include <sys/wait.h>
+#include <signal.h>
+#include <sys/signalfd.h>
 
 #include "sd-event.h"
 
-#include "hashmap.h"
+#include "forward.h"
 #include "inotify-util.h"
 #include "list.h"
-#include "prioq.h"
 #include "ratelimit.h"
 
 typedef enum EventSourceType {
diff --git a/src/libsystemd/sd-event/event-util.c b/src/libsystemd/sd-event/event-util.c
index d7f15882c8..7e8c481bcf 100644
--- a/src/libsystemd/sd-event/event-util.c
+++ b/src/libsystemd/sd-event/event-util.c
@@ -1,13 +1,16 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
+#include "sd-event.h"
 
-#include "errno-util.h"
+#include "alloc-util.h"
 #include "event-source.h"
 #include "event-util.h"
 #include "fd-util.h"
+#include "hash-funcs.h"
 #include "log.h"
+#include "pidref.h"
 #include "string-util.h"
+#include "time-util.h"
 
 #define SI_FLAG_FORWARD  (INT32_C(1) << 30)
 #define SI_FLAG_POSITIVE (INT32_C(1) << 29)
diff --git a/src/libsystemd/sd-event/event-util.h b/src/libsystemd/sd-event/event-util.h
index 02dc3929ca..7cc56a38d8 100644
--- a/src/libsystemd/sd-event/event-util.h
+++ b/src/libsystemd/sd-event/event-util.h
@@ -1,12 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
-
 #include "sd-event.h"
 
-#include "hash-funcs.h"
-#include "pidref.h"
+#include "forward.h"
 
 extern const struct hash_ops event_source_hash_ops;
 
diff --git a/src/libsystemd/sd-event/sd-event.c b/src/libsystemd/sd-event/sd-event.c
index 5e055330e0..6d8a207b5d 100644
--- a/src/libsystemd/sd-event/sd-event.c
+++ b/src/libsystemd/sd-event/sd-event.c
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <sys/epoll.h>
+#include <stdlib.h>
 #include <sys/timerfd.h>
 #include <sys/wait.h>
 #include <threads.h>
@@ -11,20 +11,19 @@
 #include "sd-messages.h"
 
 #include "alloc-util.h"
-#include "env-util.h"
+#include "errno-util.h"
 #include "event-source.h"
 #include "fd-util.h"
-#include "fs-util.h"
+#include "format-util.h"
 #include "glyph-util.h"
 #include "hashmap.h"
 #include "hexdecoct.h"
 #include "list.h"
+#include "log.h"
 #include "logarithm.h"
-#include "macro.h"
 #include "mallinfo-util.h"
 #include "memory-util.h"
 #include "missing_magic.h"
-#include "missing_syscall.h"
 #include "missing_wait.h"
 #include "origin-id.h"
 #include "path-util.h"
@@ -34,6 +33,7 @@
 #include "psi-util.h"
 #include "set.h"
 #include "signal-util.h"
+#include "siphash24.h"
 #include "socket-util.h"
 #include "stat-util.h"
 #include "string-table.h"
diff --git a/src/libsystemd/sd-event/test-event.c b/src/libsystemd/sd-event/test-event.c
index 6394507994..23a45c7276 100644
--- a/src/libsystemd/sd-event/test-event.c
+++ b/src/libsystemd/sd-event/test-event.c
@@ -1,22 +1,17 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#if HAVE_PIDFD_OPEN
-#include <sys/pidfd.h>
-#endif
 #include <sys/wait.h>
 #include <unistd.h>
 
 #include "sd-event.h"
 
 #include "alloc-util.h"
-#include "exec-util.h"
 #include "fd-util.h"
 #include "fs-util.h"
 #include "log.h"
-#include "macro.h"
-#include "missing_syscall.h"
 #include "parse-util.h"
 #include "path-util.h"
+#include "pidfd-util.h"
 #include "process-util.h"
 #include "random-util.h"
 #include "rm-rf.h"
@@ -24,6 +19,7 @@
 #include "stdio-util.h"
 #include "string-util.h"
 #include "tests.h"
+#include "time-util.h"
 #include "tmpfile-util.h"
 
 static int prepare_handler(sd_event_source *s, void *userdata) {
diff --git a/src/libsystemd/sd-hwdb/hwdb-internal.h b/src/libsystemd/sd-hwdb/hwdb-internal.h
index b26eb594ed..65c810416a 100644
--- a/src/libsystemd/sd-hwdb/hwdb-internal.h
+++ b/src/libsystemd/sd-hwdb/hwdb-internal.h
@@ -1,11 +1,10 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdint.h>
 #include <sys/stat.h>
 
-#include "constants.h"
-#include "hashmap.h"
+#include "forward.h"
+#include "iterator.h"
 #include "sparse-endian.h"
 
 #define HWDB_SIG { 'K', 'S', 'L', 'P', 'H', 'H', 'R', 'H' }
diff --git a/src/libsystemd/sd-hwdb/sd-hwdb.c b/src/libsystemd/sd-hwdb/sd-hwdb.c
index fce62e12e4..bc96e40907 100644
--- a/src/libsystemd/sd-hwdb/sd-hwdb.c
+++ b/src/libsystemd/sd-hwdb/sd-hwdb.c
@@ -3,9 +3,7 @@
   Copyright © 2008 Alan Jenkins <alan.christopher.jenkins@googlemail.com>
 ***/
 
-#include <errno.h>
 #include <fnmatch.h>
-#include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/mman.h>
@@ -21,7 +19,6 @@
 #include "log.h"
 #include "nulstr-util.h"
 #include "string-util.h"
-#include "time-util.h"
 
 struct linebuf {
         char bytes[LINE_MAX];
diff --git a/src/libsystemd/sd-id128/id128-util.c b/src/libsystemd/sd-id128/id128-util.c
index 44b0e1ddda..f5dcf2ecf2 100644
--- a/src/libsystemd/sd-id128/id128-util.c
+++ b/src/libsystemd/sd-id128/id128-util.c
@@ -1,19 +1,19 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
 #include <fcntl.h>
+#include <stdlib.h>
+#include <sys/socket.h>
 #include <unistd.h>
 
 #include "fd-util.h"
 #include "fs-util.h"
-#include "hexdecoct.h"
+#include "hash-funcs.h"
 #include "id128-util.h"
 #include "io-util.h"
-#include "log.h"
 #include "namespace-util.h"
 #include "process-util.h"
 #include "sha256.h"
-#include "stdio-util.h"
+#include "siphash24.h"
 #include "string-util.h"
 #include "strv.h"
 #include "sync-util.h"
diff --git a/src/libsystemd/sd-id128/id128-util.h b/src/libsystemd/sd-id128/id128-util.h
index 458d430771..874fc9f446 100644
--- a/src/libsystemd/sd-id128/id128-util.h
+++ b/src/libsystemd/sd-id128/id128-util.h
@@ -1,14 +1,10 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <fcntl.h>
-#include <stdbool.h>
-
 #include "sd-id128.h"
 
 #include "errno-util.h"
-#include "hash-funcs.h"
-#include "macro.h"
+#include "forward.h"
 
 bool id128_is_valid(const char *s) _pure_;
 
diff --git a/src/libsystemd/sd-id128/sd-id128.c b/src/libsystemd/sd-id128/sd-id128.c
index 54fb403a54..54fab9284a 100644
--- a/src/libsystemd/sd-id128/sd-id128.c
+++ b/src/libsystemd/sd-id128/sd-id128.c
@@ -1,9 +1,8 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
 #include <fcntl.h>
+#include <stdlib.h>
 #include <threads.h>
-#include <unistd.h>
 
 #include "sd-id128.h"
 
@@ -13,10 +12,7 @@
 #include "hexdecoct.h"
 #include "hmac.h"
 #include "id128-util.h"
-#include "io-util.h"
 #include "keyring-util.h"
-#include "log.h"
-#include "macro.h"
 #include "missing_syscall.h"
 #include "path-util.h"
 #include "random-util.h"
diff --git a/src/libsystemd/sd-journal/audit-type.h b/src/libsystemd/sd-journal/audit-type.h
index fffc58ad92..85b4c47bb0 100644
--- a/src/libsystemd/sd-journal/audit-type.h
+++ b/src/libsystemd/sd-journal/audit-type.h
@@ -3,8 +3,7 @@
 
 #include <stdio.h>
 
-#include "alloc-util.h"
-#include "macro.h"
+#include "forward.h"
 
 const char* audit_type_to_string(int type);
 int audit_type_from_string(const char *s);
diff --git a/src/libsystemd/sd-journal/catalog.c b/src/libsystemd/sd-journal/catalog.c
index 1ecf335fb8..3ca3b2dab4 100644
--- a/src/libsystemd/sd-journal/catalog.c
+++ b/src/libsystemd/sd-journal/catalog.c
@@ -1,13 +1,11 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
 #include <fcntl.h>
 #include <locale.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
-#include <sys/types.h>
-#include <unistd.h>
 
 #include "sd-id128.h"
 
@@ -22,7 +20,6 @@
 #include "log.h"
 #include "memory-util.h"
 #include "mkdir.h"
-#include "path-util.h"
 #include "siphash24.h"
 #include "sort-util.h"
 #include "sparse-endian.h"
diff --git a/src/libsystemd/sd-journal/catalog.h b/src/libsystemd/sd-journal/catalog.h
index e6a8c9b8db..c2a20aaddb 100644
--- a/src/libsystemd/sd-journal/catalog.h
+++ b/src/libsystemd/sd-journal/catalog.h
@@ -1,12 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
-#include <stdio.h>
-
-#include "sd-id128.h"
-
-#include "hashmap.h"
+#include "forward.h"
 
 int catalog_import_file(OrderedHashmap **h, const char *path);
 int catalog_update(const char *database, const char *root, const char* const *dirs);
diff --git a/src/libsystemd/sd-journal/fsprg.h b/src/libsystemd/sd-journal/fsprg.h
index a0594cd438..f65c5f9e06 100644
--- a/src/libsystemd/sd-journal/fsprg.h
+++ b/src/libsystemd/sd-journal/fsprg.h
@@ -7,10 +7,7 @@
  * Contact: fsprg@point-at-infinity.org
  */
 
-#include <inttypes.h>
-#include <sys/types.h>
-
-#include "macro.h"
+#include "forward.h"
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/src/libsystemd/sd-journal/journal-authenticate.c b/src/libsystemd/sd-journal/journal-authenticate.c
index 9ad9ce3ef3..60a60f26f5 100644
--- a/src/libsystemd/sd-journal/journal-authenticate.c
+++ b/src/libsystemd/sd-journal/journal-authenticate.c
@@ -2,7 +2,9 @@
 
 #include <fcntl.h>
 #include <sys/mman.h>
+#include <sys/stat.h>
 
+#include "alloc-util.h"
 #include "fd-util.h"
 #include "fsprg.h"
 #include "gcrypt-util.h"
@@ -12,6 +14,7 @@
 #include "journal-file.h"
 #include "log.h"
 #include "memory-util.h"
+#include "string-util.h"
 #include "time-util.h"
 
 static void* fssheader_free(FSSHeader *p) {
diff --git a/src/libsystemd/sd-journal/journal-authenticate.h b/src/libsystemd/sd-journal/journal-authenticate.h
index e895722865..21c69ad30b 100644
--- a/src/libsystemd/sd-journal/journal-authenticate.h
+++ b/src/libsystemd/sd-journal/journal-authenticate.h
@@ -1,8 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
-
+#include "forward.h"
 #include "journal-file.h"
 
 int journal_file_append_tag(JournalFile *f);
diff --git a/src/libsystemd/sd-journal/journal-def.h b/src/libsystemd/sd-journal/journal-def.h
index 28cccca21a..f3fef931d0 100644
--- a/src/libsystemd/sd-journal/journal-def.h
+++ b/src/libsystemd/sd-journal/journal-def.h
@@ -1,11 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <errno.h>
-
 #include "sd-id128.h"
 
-#include "macro.h"
+#include "forward.h"
 #include "sparse-endian.h"
 
 /*
diff --git a/src/libsystemd/sd-journal/journal-file.c b/src/libsystemd/sd-journal/journal-file.c
index dfc3e8aa91..ec06ea8e20 100644
--- a/src/libsystemd/sd-journal/journal-file.c
+++ b/src/libsystemd/sd-journal/journal-file.c
@@ -1,10 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
 #include <fcntl.h>
 #include <linux/magic.h>
 #include <pthread.h>
-#include <stddef.h>
+#include <stdlib.h>
 #include <sys/mman.h>
 #include <sys/statvfs.h>
 #include <sys/uio.h>
@@ -21,6 +20,7 @@
 #include "format-util.h"
 #include "fs-util.h"
 #include "gcrypt-util.h"
+#include "hashmap.h"
 #include "id128-util.h"
 #include "journal-authenticate.h"
 #include "journal-def.h"
@@ -30,19 +30,19 @@
 #include "log-ratelimit.h"
 #include "lookup3.h"
 #include "memory-util.h"
-#include "missing_fs.h"
 #include "parse-util.h"
 #include "path-util.h"
 #include "prioq.h"
 #include "random-util.h"
 #include "ratelimit.h"
-#include "set.h"
 #include "sort-util.h"
 #include "stat-util.h"
 #include "string-table.h"
 #include "string-util.h"
 #include "strv.h"
+#include "siphash24.h"
 #include "sync-util.h"
+#include "time-util.h"
 #include "user-util.h"
 #include "xattr-util.h"
 
diff --git a/src/libsystemd/sd-journal/journal-file.h b/src/libsystemd/sd-journal/journal-file.h
index 89b06b0834..12a6646853 100644
--- a/src/libsystemd/sd-journal/journal-file.h
+++ b/src/libsystemd/sd-journal/journal-file.h
@@ -1,20 +1,13 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <inttypes.h>
-#include <sys/uio.h>
-
-#include "sd-event.h"
-#include "sd-id128.h"
-
 #include "compress.h"
+#include "forward.h"
 #include "gcrypt-util.h"
-#include "hashmap.h"
 #include "journal-def.h"
 #include "missing_fcntl.h"
 #include "mmap-cache.h"
 #include "sparse-endian.h"
-#include "time-util.h"
 
 typedef struct JournalMetrics {
         /* For all these: UINT64_MAX means "pick automatically", and 0 means "no limit enforced" */
diff --git a/src/libsystemd/sd-journal/journal-internal.h b/src/libsystemd/sd-journal/journal-internal.h
index badec0e943..15dc934db0 100644
--- a/src/libsystemd/sd-journal/journal-internal.h
+++ b/src/libsystemd/sd-journal/journal-internal.h
@@ -1,18 +1,10 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <inttypes.h>
-#include <stdbool.h>
-#include <sys/types.h>
-
-#include "sd-id128.h"
-#include "sd-journal.h"
-
-#include "hashmap.h"
-#include "journal-def.h"
 #include "journal-file.h"
 #include "list.h"
-#include "prioq.h"
+#include "forward.h"
+#include "time-util.h"
 
 #define JOURNAL_FILES_MAX 7168u
 
@@ -28,7 +20,7 @@ typedef enum MatchType {
         MATCH_AND_TERM,
 } MatchType;
 
-struct Match {
+typedef struct Match {
         MatchType type;
         Match *parent;
         LIST_FIELDS(Match, matches);
@@ -40,9 +32,9 @@ struct Match {
 
         /* For terms */
         LIST_HEAD(Match, matches);
-};
+} Match;
 
-struct Location {
+typedef struct Location {
         LocationType type;
 
         bool seqnum_set:1;
@@ -59,22 +51,22 @@ struct Location {
         sd_id128_t boot_id;
 
         uint64_t xor_hash;
-};
+} Location;
 
-struct Directory {
+typedef struct Directory {
         sd_journal *journal;
         char *path;
         int wd;
         bool is_root;
         unsigned last_seen_generation;
-};
+} Directory;
 
 typedef struct NewestByBootId {
         sd_id128_t boot_id;
         Prioq *prioq; /* JournalFile objects ordered by monotonic timestamp of last update. */
 } NewestByBootId;
 
-struct sd_journal {
+typedef struct sd_journal {
         int toplevel_fd;
 
         char *path;
@@ -134,7 +126,7 @@ struct sd_journal {
         Hashmap *directories_by_wd;
 
         Hashmap *errors;
-};
+} sd_journal;
 
 char* journal_make_match_string(sd_journal *j);
 void journal_print_header(sd_journal *j);
diff --git a/src/libsystemd/sd-journal/journal-send.c b/src/libsystemd/sd-journal/journal-send.c
index d043e1882d..8a1e0b1fdf 100644
--- a/src/libsystemd/sd-journal/journal-send.c
+++ b/src/libsystemd/sd-journal/journal-send.c
@@ -1,10 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
-#include <fcntl.h>
-#include <printf.h>
-#include <stddef.h>
-#include <sys/un.h>
 #include <unistd.h>
 #if HAVE_VALGRIND_VALGRIND_H
 #  include <valgrind/valgrind.h>
@@ -24,7 +19,6 @@
 #include "log.h"
 #include "memfd-util.h"
 #include "missing_mman.h"
-#include "missing_syscall.h"
 #include "process-util.h"
 #include "socket-util.h"
 #include "stdio-util.h"
diff --git a/src/libsystemd/sd-journal/journal-send.h b/src/libsystemd/sd-journal/journal-send.h
index 6fe6325090..e5394e9471 100644
--- a/src/libsystemd/sd-journal/journal-send.h
+++ b/src/libsystemd/sd-journal/journal-send.h
@@ -1,9 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
-#include <stddef.h>
-
 #include "syslog-util.h"
 
 int journal_fd_nonblock(bool nonblock);
diff --git a/src/libsystemd/sd-journal/journal-vacuum.c b/src/libsystemd/sd-journal/journal-vacuum.c
index b50a0179d0..7301b72e95 100644
--- a/src/libsystemd/sd-journal/journal-vacuum.c
+++ b/src/libsystemd/sd-journal/journal-vacuum.c
@@ -12,7 +12,6 @@
 #include "format-util.h"
 #include "fs-util.h"
 #include "journal-def.h"
-#include "journal-file.h"
 #include "journal-internal.h"
 #include "journal-vacuum.h"
 #include "log.h"
diff --git a/src/libsystemd/sd-journal/journal-vacuum.h b/src/libsystemd/sd-journal/journal-vacuum.h
index d87c847da6..e134a9d4b9 100644
--- a/src/libsystemd/sd-journal/journal-vacuum.h
+++ b/src/libsystemd/sd-journal/journal-vacuum.h
@@ -1,9 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <inttypes.h>
-#include <stdbool.h>
-
-#include "time-util.h"
+#include "forward.h"
 
 int journal_directory_vacuum(const char *directory, uint64_t max_use, uint64_t n_max_files, usec_t max_retention_usec, usec_t *oldest_usec, bool verbose);
diff --git a/src/libsystemd/sd-journal/journal-verify.c b/src/libsystemd/sd-journal/journal-verify.c
index 87d66aac43..db566288b7 100644
--- a/src/libsystemd/sd-journal/journal-verify.c
+++ b/src/libsystemd/sd-journal/journal-verify.c
@@ -1,9 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <fcntl.h>
-#include <stddef.h>
 #include <sys/mman.h>
-#include <unistd.h>
 
 #include "alloc-util.h"
 #include "ansi-color.h"
@@ -17,9 +15,8 @@
 #include "journal-file.h"
 #include "journal-verify.h"
 #include "log.h"
-#include "lookup3.h"
-#include "macro.h"
 #include "terminal-util.h"
+#include "time-util.h"
 #include "tmpfile-util.h"
 
 static void draw_progress(uint64_t p, usec_t *last_usec) {
diff --git a/src/libsystemd/sd-journal/lookup3.h b/src/libsystemd/sd-journal/lookup3.h
index 04e493e95e..e4709490e2 100644
--- a/src/libsystemd/sd-journal/lookup3.h
+++ b/src/libsystemd/sd-journal/lookup3.h
@@ -1,10 +1,7 @@
 /* SPDX-License-Identifier: LicenseRef-lookup3-public-domain */
 #pragma once
 
-#include <inttypes.h>
-#include <sys/types.h>
-
-#include "macro.h"
+#include "forward.h"
 
 uint32_t jenkins_hashword(const uint32_t *k, size_t length, uint32_t initval) _pure_;
 void jenkins_hashword2(const uint32_t *k, size_t length, uint32_t *pc, uint32_t *pb);
diff --git a/src/libsystemd/sd-journal/mmap-cache.c b/src/libsystemd/sd-journal/mmap-cache.c
index 49e1e5fc81..2c2f6c677d 100644
--- a/src/libsystemd/sd-journal/mmap-cache.c
+++ b/src/libsystemd/sd-journal/mmap-cache.c
@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
 #include <stdlib.h>
 #include <sys/mman.h>
 
@@ -11,7 +10,6 @@
 #include "hashmap.h"
 #include "list.h"
 #include "log.h"
-#include "macro.h"
 #include "memory-util.h"
 #include "mmap-cache.h"
 #include "sigbus.h"
diff --git a/src/libsystemd/sd-journal/mmap-cache.h b/src/libsystemd/sd-journal/mmap-cache.h
index 3e088ef8ef..bdd3494589 100644
--- a/src/libsystemd/sd-journal/mmap-cache.h
+++ b/src/libsystemd/sd-journal/mmap-cache.h
@@ -1,12 +1,8 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <errno.h>
-#include <stdbool.h>
-#include <sys/stat.h>
-
+#include "forward.h"
 #include "journal-def.h"
-#include "memory-util.h"
 
 typedef struct MMapCache MMapCache;
 typedef struct MMapFileDescriptor MMapFileDescriptor;
diff --git a/src/libsystemd/sd-journal/sd-journal.c b/src/libsystemd/sd-journal/sd-journal.c
index b6d3a7f627..8ec1fe450c 100644
--- a/src/libsystemd/sd-journal/sd-journal.c
+++ b/src/libsystemd/sd-journal/sd-journal.c
@@ -1,11 +1,8 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
 #include <fcntl.h>
-#include <inttypes.h>
-#include <linux/magic.h>
 #include <poll.h>
-#include <stddef.h>
+#include <stdlib.h>
 #include <sys/inotify.h>
 #include <sys/vfs.h>
 #include <unistd.h>
@@ -14,14 +11,13 @@
 
 #include "alloc-util.h"
 #include "catalog.h"
-#include "compress.h"
 #include "dirent-util.h"
 #include "env-file.h"
 #include "escape.h"
+#include "extract-word.h"
 #include "fd-util.h"
 #include "fileio.h"
 #include "format-util.h"
-#include "fs-util.h"
 #include "hashmap.h"
 #include "hostname-util.h"
 #include "id128-util.h"
@@ -31,19 +27,21 @@
 #include "journal-file.h"
 #include "journal-internal.h"
 #include "list.h"
+#include "log.h"
 #include "lookup3.h"
 #include "nulstr-util.h"
 #include "origin-id.h"
 #include "path-util.h"
 #include "prioq.h"
-#include "process-util.h"
 #include "replace-var.h"
+#include "set.h"
 #include "sort-util.h"
 #include "stat-util.h"
 #include "stdio-util.h"
 #include "string-util.h"
 #include "strv.h"
 #include "syslog-util.h"
+#include "time-util.h"
 #include "uid-classification.h"
 
 #define JOURNAL_FILES_RECHECK_USEC (2 * USEC_PER_SEC)
diff --git a/src/libsystemd/sd-journal/test-catalog.c b/src/libsystemd/sd-journal/test-catalog.c
index ee8bd4e0ec..d86fd533f7 100644
--- a/src/libsystemd/sd-journal/test-catalog.c
+++ b/src/libsystemd/sd-journal/test-catalog.c
@@ -1,7 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
-#include <fcntl.h>
 #include <locale.h>
 #include <unistd.h>
 
@@ -10,12 +8,8 @@
 #include "alloc-util.h"
 #include "catalog.h"
 #include "fd-util.h"
-#include "fs-util.h"
+#include "hashmap.h"
 #include "log.h"
-#include "macro.h"
-#include "path-util.h"
-#include "string-util.h"
-#include "strv.h"
 #include "tests.h"
 #include "tmpfile-util.h"
 
diff --git a/src/libsystemd/sd-journal/test-journal-append.c b/src/libsystemd/sd-journal/test-journal-append.c
index ff4f86329b..6530cdae8f 100644
--- a/src/libsystemd/sd-journal/test-journal-append.c
+++ b/src/libsystemd/sd-journal/test-journal-append.c
@@ -6,8 +6,6 @@
 #include <unistd.h>
 
 #include "chattr-util.h"
-#include "fd-util.h"
-#include "fs-util.h"
 #include "iovec-util.h"
 #include "journal-file-util.h"
 #include "log.h"
@@ -15,9 +13,8 @@
 #include "parse-util.h"
 #include "random-util.h"
 #include "rm-rf.h"
-#include "strv.h"
-#include "terminal-util.h"
 #include "tests.h"
+#include "time-util.h"
 #include "tmpfile-util.h"
 
 static int journal_append_message(JournalFile *mj, const char *message) {
diff --git a/src/libsystemd/sd-journal/test-journal-enum.c b/src/libsystemd/sd-journal/test-journal-enum.c
index d101fe76f2..cc17ea1891 100644
--- a/src/libsystemd/sd-journal/test-journal-enum.c
+++ b/src/libsystemd/sd-journal/test-journal-enum.c
@@ -4,9 +4,6 @@
 
 #include "sd-journal.h"
 
-#include "journal-internal.h"
-#include "log.h"
-#include "macro.h"
 #include "tests.h"
 
 int main(int argc, char *argv[]) {
diff --git a/src/libsystemd/sd-journal/test-journal-file.c b/src/libsystemd/sd-journal/test-journal-file.c
index 729de1fe52..52b1328fb0 100644
--- a/src/libsystemd/sd-journal/test-journal-file.c
+++ b/src/libsystemd/sd-journal/test-journal-file.c
@@ -1,12 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
-#include <stdlib.h>
 #include <unistd.h>
 
 #include "journal-file.h"
 #include "tests.h"
-#include "user-util.h"
 
 static void test_journal_file_parse_uid_from_filename_simple(
                 const char *path,
diff --git a/src/libsystemd/sd-journal/test-journal-flush.c b/src/libsystemd/sd-journal/test-journal-flush.c
index 05252d7f09..ef5acca9c0 100644
--- a/src/libsystemd/sd-journal/test-journal-flush.c
+++ b/src/libsystemd/sd-journal/test-journal-flush.c
@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <fcntl.h>
-#include <unistd.h>
+#include <stdlib.h>
 
 #include "sd-journal.h"
 
@@ -13,13 +13,13 @@
 #include "journal-file-util.h"
 #include "journal-internal.h"
 #include "logs-show.h"
-#include "macro.h"
 #include "output-mode.h"
 #include "path-util.h"
 #include "rm-rf.h"
 #include "string-util.h"
 #include "strv.h"
 #include "tests.h"
+#include "time-util.h"
 #include "tmpfile-util.h"
 
 static int open_archive_file(sd_journal **ret) {
diff --git a/src/libsystemd/sd-journal/test-journal-init.c b/src/libsystemd/sd-journal/test-journal-init.c
index 45663b0dbe..7f7e12fbdd 100644
--- a/src/libsystemd/sd-journal/test-journal-init.c
+++ b/src/libsystemd/sd-journal/test-journal-init.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <stdlib.h>
 #include <unistd.h>
 
 #include "sd-journal.h"
diff --git a/src/libsystemd/sd-journal/test-journal-interleaving.c b/src/libsystemd/sd-journal/test-journal-interleaving.c
index 9703f46c42..d5d6506a44 100644
--- a/src/libsystemd/sd-journal/test-journal-interleaving.c
+++ b/src/libsystemd/sd-journal/test-journal-interleaving.c
@@ -19,6 +19,7 @@
 #include "rm-rf.h"
 #include "strv.h"
 #include "tests.h"
+#include "time-util.h"
 #include "tmpfile-util.h"
 
 /* This program tests skipping around in a multi-file journal. */
diff --git a/src/libsystemd/sd-journal/test-journal-match.c b/src/libsystemd/sd-journal/test-journal-match.c
index c2c345fb07..2b3886445d 100644
--- a/src/libsystemd/sd-journal/test-journal-match.c
+++ b/src/libsystemd/sd-journal/test-journal-match.c
@@ -6,8 +6,6 @@
 
 #include "alloc-util.h"
 #include "journal-internal.h"
-#include "log.h"
-#include "string-util.h"
 #include "tests.h"
 
 int main(int argc, char *argv[]) {
diff --git a/src/libsystemd/sd-journal/test-journal-send.c b/src/libsystemd/sd-journal/test-journal-send.c
index ca1fe7c303..e4959521f6 100644
--- a/src/libsystemd/sd-journal/test-journal-send.c
+++ b/src/libsystemd/sd-journal/test-journal-send.c
@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
 #include <stdlib.h>
 #include <unistd.h>
 
@@ -8,8 +7,6 @@
 
 #include "fileio.h"
 #include "journal-send.h"
-#include "macro.h"
-#include "memory-util.h"
 #include "tests.h"
 
 TEST(journal_print) {
diff --git a/src/libsystemd/sd-journal/test-journal-stream.c b/src/libsystemd/sd-journal/test-journal-stream.c
index c8103bf113..512ec132ef 100644
--- a/src/libsystemd/sd-journal/test-journal-stream.c
+++ b/src/libsystemd/sd-journal/test-journal-stream.c
@@ -11,10 +11,10 @@
 #include "journal-file-util.h"
 #include "journal-internal.h"
 #include "log.h"
-#include "macro.h"
 #include "parse-util.h"
 #include "rm-rf.h"
 #include "tests.h"
+#include "time-util.h"
 
 #define N_ENTRIES 200
 
diff --git a/src/libsystemd/sd-journal/test-journal-verify.c b/src/libsystemd/sd-journal/test-journal-verify.c
index 9bf4f86258..bc66a96aee 100644
--- a/src/libsystemd/sd-journal/test-journal-verify.c
+++ b/src/libsystemd/sd-journal/test-journal-verify.c
@@ -2,6 +2,7 @@
 
 #include <fcntl.h>
 #include <stdio.h>
+#include <sys/stat.h>
 #include <unistd.h>
 
 #include "ansi-color.h"
@@ -13,9 +14,8 @@
 #include "log.h"
 #include "mmap-cache.h"
 #include "rm-rf.h"
-#include "strv.h"
-#include "terminal-util.h"
 #include "tests.h"
+#include "time-util.h"
 
 #define N_ENTRIES 6000
 #define RANDOM_RANGE 77
diff --git a/src/libsystemd/sd-journal/test-journal.c b/src/libsystemd/sd-journal/test-journal.c
index 6f6aa9d275..fb0a02d9bf 100644
--- a/src/libsystemd/sd-journal/test-journal.c
+++ b/src/libsystemd/sd-journal/test-journal.c
@@ -12,6 +12,7 @@
 #include "log.h"
 #include "rm-rf.h"
 #include "tests.h"
+#include "time-util.h"
 
 static bool arg_keep = false;
 
diff --git a/src/libsystemd/sd-journal/test-mmap-cache.c b/src/libsystemd/sd-journal/test-mmap-cache.c
index ce5ea123c6..dc7e334247 100644
--- a/src/libsystemd/sd-journal/test-mmap-cache.c
+++ b/src/libsystemd/sd-journal/test-mmap-cache.c
@@ -1,12 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <fcntl.h>
-#include <stdlib.h>
 #include <sys/mman.h>
 #include <unistd.h>
 
 #include "fd-util.h"
-#include "macro.h"
 #include "mmap-cache.h"
 #include "tests.h"
 #include "tmpfile-util.h"
diff --git a/src/libsystemd/sd-json/json-internal.h b/src/libsystemd/sd-json/json-internal.h
index 9ecdd6bb1a..d42d1c6be5 100644
--- a/src/libsystemd/sd-json/json-internal.h
+++ b/src/libsystemd/sd-json/json-internal.h
@@ -2,11 +2,7 @@
 
 #pragma once
 
-#include <stdbool.h>
-
-#include "sd-json.h"
-
-#include "macro.h"
+#include "forward.h"
 
 /* This header should include all prototypes only the JSON parser itself and
  * its tests need access to. Normal code consuming the JSON parser should not
diff --git a/src/libsystemd/sd-json/json-util.c b/src/libsystemd/sd-json/json-util.c
index a4beb54cba..2c7f3240b6 100644
--- a/src/libsystemd/sd-json/json-util.c
+++ b/src/libsystemd/sd-json/json-util.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <netinet/in.h>
 #include <sys/sysmacros.h>
 
 #include "alloc-util.h"
@@ -8,15 +9,16 @@
 #include "errno-util.h"
 #include "fd-util.h"
 #include "glyph-util.h"
-#include "in-addr-util.h"
 #include "iovec-util.h"
 #include "json-util.h"
 #include "log.h"
 #include "mountpoint-util.h"
 #include "parse-util.h"
 #include "path-util.h"
+#include "pidref.h"
 #include "process-util.h"
 #include "stat-util.h"
+#include "stdio-util.h"
 #include "string-util.h"
 #include "strv.h"
 #include "syslog-util.h"
diff --git a/src/libsystemd/sd-json/json-util.h b/src/libsystemd/sd-json/json-util.h
index 861c1876ff..0d0f41bf37 100644
--- a/src/libsystemd/sd-json/json-util.h
+++ b/src/libsystemd/sd-json/json-util.h
@@ -5,9 +5,9 @@
 
 #include "sd-json.h"
 
+#include "forward.h"
 #include "log.h"
-#include "macro.h"
-#include "pidref.h"
+#include "string-util.h"
 
 #define JSON_VARIANT_REPLACE(v, q)        \
         do {                              \
diff --git a/src/libsystemd/sd-json/sd-json.c b/src/libsystemd/sd-json/sd-json.c
index 03f94ce663..9add7be9a8 100644
--- a/src/libsystemd/sd-json/sd-json.c
+++ b/src/libsystemd/sd-json/sd-json.c
@@ -1,10 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
 #include <locale.h>
-#include <stdarg.h>
 #include <stdlib.h>
-#include <sys/types.h>
 
 #include "sd-json.h"
 #include "sd-messages.h"
@@ -15,31 +12,26 @@
 #include "errno-util.h"
 #include "escape.h"
 #include "ether-addr-util.h"
-#include "fd-util.h"
 #include "fileio.h"
 #include "float.h"
-#include "glyph-util.h"
 #include "hexdecoct.h"
 #include "in-addr-util.h"
-#include "iovec-util.h"
 #include "json-internal.h"
 #include "json-util.h"
 #include "log.h"
-#include "macro.h"
 #include "math-util.h"
 #include "memory-util.h"
 #include "memstream-util.h"
 #include "ordered-set.h"
 #include "parse-util.h"
-#include "path-util.h"
-#include "process-util.h"
+#include "pidref.h"
 #include "ratelimit.h"
-#include "set.h"
 #include "signal-util.h"
 #include "string-table.h"
 #include "string-util.h"
 #include "strv.h"
 #include "terminal-util.h"
+#include "time-util.h"
 #include "user-util.h"
 #include "utf8.h"
 
diff --git a/src/libsystemd/sd-login/sd-login.c b/src/libsystemd/sd-login/sd-login.c
index cf5f39b90a..efe40c70f5 100644
--- a/src/libsystemd/sd-login/sd-login.c
+++ b/src/libsystemd/sd-login/sd-login.c
@@ -1,6 +1,5 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
 #include <poll.h>
 #include <sys/inotify.h>
 #include <unistd.h>
@@ -18,15 +17,12 @@
 #include "fs-util.h"
 #include "hostname-util.h"
 #include "io-util.h"
-#include "log.h"
 #include "login-util.h"
-#include "macro.h"
 #include "parse-util.h"
 #include "path-util.h"
 #include "pidfd-util.h"
-#include "process-util.h"
+#include "pidref.h"
 #include "socket-util.h"
-#include "stdio-util.h"
 #include "string-util.h"
 #include "strv.h"
 #include "user-util.h"
diff --git a/src/libsystemd/sd-login/test-login.c b/src/libsystemd/sd-login/test-login.c
index f7dab9b723..a4ab2659b2 100644
--- a/src/libsystemd/sd-login/test-login.c
+++ b/src/libsystemd/sd-login/test-login.c
@@ -1,9 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <poll.h>
-#if HAVE_PIDFD_OPEN
-#include <sys/pidfd.h>
-#endif
+#include <sys/socket.h>
 
 #include "sd-login.h"
 
@@ -13,8 +11,7 @@
 #include "fd-util.h"
 #include "format-util.h"
 #include "log.h"
-#include "missing_syscall.h"
-#include "mountpoint-util.h"
+#include "pidfd-util.h"
 #include "process-util.h"
 #include "string-util.h"
 #include "strv.h"
diff --git a/src/libsystemd/sd-login/test-sd-login.c b/src/libsystemd/sd-login/test-sd-login.c
index a388a199a9..1153fb0965 100644
--- a/src/libsystemd/sd-login/test-sd-login.c
+++ b/src/libsystemd/sd-login/test-sd-login.c
@@ -3,11 +3,13 @@
 #include "sd-login.h"
 
 #include "alloc-util.h"
+#include "errno-util.h"
 #include "format-util.h"
+#include "log.h"
 #include "main-func.h"
 #include "parse-util.h"
+#include "string-util.h"
 #include "strv.h"
-#include "tests.h"
 
 static const char *arg_verb = NULL;  /* NULL means all */
 static pid_t arg_pid = 0;            /* 0 == self */
diff --git a/src/libsystemd/sd-netlink/netlink-genl.c b/src/libsystemd/sd-netlink/netlink-genl.c
index 9c31105772..d4d33ae52d 100644
--- a/src/libsystemd/sd-netlink/netlink-genl.c
+++ b/src/libsystemd/sd-netlink/netlink-genl.c
@@ -5,10 +5,12 @@
 #include "sd-netlink.h"
 
 #include "alloc-util.h"
+#include "hashmap.h"
 #include "log.h"
 #include "netlink-genl.h"
 #include "netlink-internal.h"
 #include "netlink-types.h"
+#include "string-util.h"
 
 typedef struct GenericNetlinkFamily {
         sd_netlink *genl;
diff --git a/src/libsystemd/sd-netlink/netlink-genl.h b/src/libsystemd/sd-netlink/netlink-genl.h
index b06be05952..ea9135ac32 100644
--- a/src/libsystemd/sd-netlink/netlink-genl.h
+++ b/src/libsystemd/sd-netlink/netlink-genl.h
@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "sd-netlink.h"
+#include "forward.h"
 
 #define CTRL_GENL_NAME "nlctrl"
 
diff --git a/src/libsystemd/sd-netlink/netlink-internal.h b/src/libsystemd/sd-netlink/netlink-internal.h
index 7346902bdc..625b73263a 100644
--- a/src/libsystemd/sd-netlink/netlink-internal.h
+++ b/src/libsystemd/sd-netlink/netlink-internal.h
@@ -2,14 +2,11 @@
 #pragma once
 
 #include <linux/netlink.h>
+#include <sys/socket.h>
 
-#include "sd-netlink.h"
-
+#include "forward.h"
 #include "list.h"
 #include "netlink-types.h"
-#include "ordered-set.h"
-#include "prioq.h"
-#include "time-util.h"
 
 #define NETLINK_DEFAULT_TIMEOUT_USEC ((usec_t) (25 * USEC_PER_SEC))
 
@@ -40,7 +37,7 @@ typedef enum NetlinkSlotType {
         _NETLINK_SLOT_INVALID = -EINVAL,
 } NetlinkSlotType;
 
-struct sd_netlink_slot {
+typedef struct sd_netlink_slot {
         unsigned n_ref;
         NetlinkSlotType type:8;
         bool floating;
@@ -56,9 +53,9 @@ struct sd_netlink_slot {
                 struct reply_callback reply_callback;
                 struct match_callback match_callback;
         };
-};
+} sd_netlink_slot;
 
-struct sd_netlink {
+typedef struct sd_netlink {
         unsigned n_ref;
 
         int fd;
@@ -98,7 +95,7 @@ struct sd_netlink {
 
         Hashmap *genl_family_by_name;
         Hashmap *genl_family_by_id;
-};
+} sd_netlink;
 
 struct netlink_attribute {
         size_t offset; /* offset from hdr to attribute */
@@ -113,7 +110,7 @@ struct netlink_container {
         uint16_t max_attribute; /* the maximum attribute in container */
 };
 
-struct sd_netlink_message {
+typedef struct sd_netlink_message {
         unsigned n_ref;
 
         int protocol;
@@ -125,7 +122,7 @@ struct sd_netlink_message {
         bool sealed:1;
 
         sd_netlink_message *next; /* next in a chain of multi-part messages */
-};
+} sd_netlink_message;
 
 int message_new_empty(sd_netlink *nl, sd_netlink_message **ret);
 int message_new_full(
@@ -138,10 +135,7 @@ int message_new_full(
 int message_new(sd_netlink *nl, sd_netlink_message **ret, uint16_t type, uint16_t flags);
 int message_new_synthetic_error(sd_netlink *nl, int error, uint32_t serial, sd_netlink_message **ret);
 
-static inline uint32_t message_get_serial(sd_netlink_message *m) {
-        assert(m);
-        return ASSERT_PTR(m->hdr)->nlmsg_seq;
-}
+uint32_t message_get_serial(sd_netlink_message *m);
 
 void message_seal(sd_netlink_message *m);
 
diff --git a/src/libsystemd/sd-netlink/netlink-message-nfnl.c b/src/libsystemd/sd-netlink/netlink-message-nfnl.c
index 321b9b2006..d33a690e36 100644
--- a/src/libsystemd/sd-netlink/netlink-message-nfnl.c
+++ b/src/libsystemd/sd-netlink/netlink-message-nfnl.c
@@ -3,15 +3,14 @@
 #include <linux/netfilter.h>
 #include <linux/netfilter/nf_tables.h>
 #include <linux/netfilter/nfnetlink.h>
-#include <netinet/in.h>
 
 #include "sd-netlink.h"
 
 #include "alloc-util.h"
+#include "errno-util.h"
 #include "iovec-util.h"
 #include "log.h"
 #include "netlink-internal.h"
-#include "netlink-types.h"
 #include "netlink-util.h"
 
 bool nfproto_is_valid(int nfproto) {
diff --git a/src/libsystemd/sd-netlink/netlink-message-rtnl.c b/src/libsystemd/sd-netlink/netlink-message-rtnl.c
index b730b63fb0..ee6bba8d03 100644
--- a/src/libsystemd/sd-netlink/netlink-message-rtnl.c
+++ b/src/libsystemd/sd-netlink/netlink-message-rtnl.c
@@ -4,18 +4,11 @@
 #include <linux/if_addrlabel.h>
 #include <linux/if_bridge.h>
 #include <linux/nexthop.h>
-#include <netinet/in.h>
-#include <stdbool.h>
-#include <unistd.h>
 
 #include "sd-netlink.h"
 
-#include "format-util.h"
-#include "log.h"
+#include "in-addr-util.h"
 #include "netlink-internal.h"
-#include "netlink-types.h"
-#include "netlink-util.h"
-#include "socket-util.h"
 
 static bool rtnl_message_type_is_neigh(uint16_t type) {
         return IN_SET(type, RTM_NEWNEIGH, RTM_GETNEIGH, RTM_DELNEIGH);
diff --git a/src/libsystemd/sd-netlink/netlink-message.c b/src/libsystemd/sd-netlink/netlink-message.c
index 76617b686d..e55b0f0da5 100644
--- a/src/libsystemd/sd-netlink/netlink-message.c
+++ b/src/libsystemd/sd-netlink/netlink-message.c
@@ -1,19 +1,18 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <netinet/in.h>
-#include <stdbool.h>
-#include <unistd.h>
 
 #include "sd-netlink.h"
 
 #include "alloc-util.h"
-#include "format-util.h"
+#include "ether-addr-util.h"
 #include "log.h"
 #include "memory-util.h"
 #include "netlink-internal.h"
 #include "netlink-types.h"
 #include "netlink-util.h"
 #include "socket-util.h"
+#include "string-util.h"
 #include "strv.h"
 
 #define GET_CONTAINER(m, i) ((struct rtattr*)((uint8_t*)(m)->hdr + (m)->containers[i].offset))
@@ -112,6 +111,11 @@ int message_new_synthetic_error(sd_netlink *nl, int error, uint32_t serial, sd_n
         return 0;
 }
 
+uint32_t message_get_serial(sd_netlink_message *m) {
+        assert(m);
+        return ASSERT_PTR(m->hdr)->nlmsg_seq;
+}
+
 int sd_netlink_message_set_request_dump(sd_netlink_message *m, int dump) {
         assert_return(m, -EINVAL);
         assert_return(m->hdr, -EINVAL);
diff --git a/src/libsystemd/sd-netlink/netlink-slot.c b/src/libsystemd/sd-netlink/netlink-slot.c
index 145c376ca4..f1e270de6a 100644
--- a/src/libsystemd/sd-netlink/netlink-slot.c
+++ b/src/libsystemd/sd-netlink/netlink-slot.c
@@ -1,13 +1,12 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
-
 #include "sd-netlink.h"
 
 #include "alloc-util.h"
-#include "log.h"
+#include "hashmap.h"
 #include "netlink-internal.h"
 #include "netlink-slot.h"
+#include "prioq.h"
 #include "string-util.h"
 
 int netlink_slot_allocate(
diff --git a/src/libsystemd/sd-netlink/netlink-slot.h b/src/libsystemd/sd-netlink/netlink-slot.h
index 4098061d31..9ed1746b61 100644
--- a/src/libsystemd/sd-netlink/netlink-slot.h
+++ b/src/libsystemd/sd-netlink/netlink-slot.h
@@ -1,10 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
-
-#include "sd-netlink.h"
-
+#include "forward.h"
 #include "netlink-internal.h"
 
 int netlink_slot_allocate(
diff --git a/src/libsystemd/sd-netlink/netlink-sock-diag.c b/src/libsystemd/sd-netlink/netlink-sock-diag.c
index 0ed222ea20..177be0c2bc 100644
--- a/src/libsystemd/sd-netlink/netlink-sock-diag.c
+++ b/src/libsystemd/sd-netlink/netlink-sock-diag.c
@@ -5,7 +5,6 @@
 
 #include "netlink-internal.h"
 #include "netlink-sock-diag.h"
-#include "netlink-util.h"
 
 int sd_sock_diag_socket_open(sd_netlink **ret) {
         return netlink_open_family(ret, NETLINK_SOCK_DIAG);
diff --git a/src/libsystemd/sd-netlink/netlink-sock-diag.h b/src/libsystemd/sd-netlink/netlink-sock-diag.h
index 043913889c..e12e55a285 100644
--- a/src/libsystemd/sd-netlink/netlink-sock-diag.h
+++ b/src/libsystemd/sd-netlink/netlink-sock-diag.h
@@ -1,8 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <sys/types.h>
-
 #include "sd-netlink.h"
 
 /* TODO: to be exported later */
diff --git a/src/libsystemd/sd-netlink/netlink-socket.c b/src/libsystemd/sd-netlink/netlink-socket.c
index 0f00e3f2fc..28fd2bc3d9 100644
--- a/src/libsystemd/sd-netlink/netlink-socket.c
+++ b/src/libsystemd/sd-netlink/netlink-socket.c
@@ -1,19 +1,15 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <malloc.h>
-#include <netinet/in.h>
-#include <stdbool.h>
-#include <unistd.h>
-
 #include "sd-netlink.h"
 
 #include "alloc-util.h"
-#include "fd-util.h"
-#include "format-util.h"
+#include "errno-util.h"
+#include "hashmap.h"
 #include "iovec-util.h"
 #include "log.h"
 #include "netlink-internal.h"
 #include "netlink-types.h"
+#include "ordered-set.h"
 #include "socket-util.h"
 
 static int broadcast_groups_get(sd_netlink *nl) {
diff --git a/src/libsystemd/sd-netlink/netlink-types-genl.c b/src/libsystemd/sd-netlink/netlink-types-genl.c
index ebb091b90f..422ae7e691 100644
--- a/src/libsystemd/sd-netlink/netlink-types-genl.c
+++ b/src/libsystemd/sd-netlink/netlink-types-genl.c
@@ -4,12 +4,12 @@
 #include <linux/fou.h>
 #include <linux/genetlink.h>
 #include <linux/if.h>
+#include <linux/if_ether.h>
 #include <linux/if_macsec.h>
 #include <linux/l2tp.h>
 #include <linux/nl80211.h>
 #include <linux/wireguard.h>
 #include <netinet/in.h>
-#include <sys/socket.h>
 
 #include "missing_network.h"
 #include "netlink-genl.h"
diff --git a/src/libsystemd/sd-netlink/netlink-types-internal.h b/src/libsystemd/sd-netlink/netlink-types-internal.h
index 1412514f9b..d634098eba 100644
--- a/src/libsystemd/sd-netlink/netlink-types-internal.h
+++ b/src/libsystemd/sd-netlink/netlink-types-internal.h
@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include "macro.h"
 #include "netlink-types.h"
 
 /* C.f. see 'struct nla_policy' at include/net/netlink.h. */
diff --git a/src/libsystemd/sd-netlink/netlink-types-nfnl.c b/src/libsystemd/sd-netlink/netlink-types-nfnl.c
index 8ef4d45d42..289040935b 100644
--- a/src/libsystemd/sd-netlink/netlink-types-nfnl.c
+++ b/src/libsystemd/sd-netlink/netlink-types-nfnl.c
@@ -3,6 +3,7 @@
 #include <linux/if.h>
 #include <linux/netfilter/nf_tables.h>
 #include <linux/netfilter/nfnetlink.h>
+#include <linux/netlink.h>
 
 #include "netlink-types-internal.h"
 
diff --git a/src/libsystemd/sd-netlink/netlink-types-rtnl.c b/src/libsystemd/sd-netlink/netlink-types-rtnl.c
index 7af44ab144..4dc98f0504 100644
--- a/src/libsystemd/sd-netlink/netlink-types-rtnl.c
+++ b/src/libsystemd/sd-netlink/netlink-types-rtnl.c
@@ -5,24 +5,17 @@
 #include <linux/can/vxcan.h>
 #include <linux/cfm_bridge.h>
 #include <linux/fib_rules.h>
-#include <linux/fou.h>
 #include <linux/if.h>
 #include <linux/if_addr.h>
 #include <linux/if_addrlabel.h>
 #include <linux/if_bridge.h>
 #include <linux/if_link.h>
-#include <linux/if_macsec.h>
 #include <linux/if_tunnel.h>
-#include <linux/ip.h>
-#include <linux/l2tp.h>
 #include <linux/net_namespace.h>
-#include <linux/netlink.h>
 #include <linux/nexthop.h>
-#include <linux/nl80211.h>
 #include <linux/pkt_sched.h>
 #include <linux/rtnetlink.h>
 #include <linux/veth.h>
-#include <linux/wireguard.h>
 #include <netinet/in.h>
 #include <sys/socket.h>
 
diff --git a/src/libsystemd/sd-netlink/netlink-types-sdnl.c b/src/libsystemd/sd-netlink/netlink-types-sdnl.c
index 146f4177fd..6b72efb86b 100644
--- a/src/libsystemd/sd-netlink/netlink-types-sdnl.c
+++ b/src/libsystemd/sd-netlink/netlink-types-sdnl.c
@@ -1,9 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <linux/netlink.h>
 #include <linux/sock_diag.h>
 #include <linux/unix_diag.h>
 
-#include "missing_network.h"
 #include "netlink-types-internal.h"
 #include "netlink-types.h"
 
diff --git a/src/libsystemd/sd-netlink/netlink-types.c b/src/libsystemd/sd-netlink/netlink-types.c
index e10a90c5aa..c9951a040e 100644
--- a/src/libsystemd/sd-netlink/netlink-types.c
+++ b/src/libsystemd/sd-netlink/netlink-types.c
@@ -2,9 +2,9 @@
 
 #include <linux/netlink.h>
 
-#include "netlink-genl.h"
 #include "netlink-internal.h"
 #include "netlink-types-internal.h"
+#include "string-util.h"
 
 static const NLAPolicy empty_policies[1] = {
         /* fake array to avoid .types==NULL, which denotes invalid type-systems */
diff --git a/src/libsystemd/sd-netlink/netlink-types.h b/src/libsystemd/sd-netlink/netlink-types.h
index 85ff925edd..99d1246ef6 100644
--- a/src/libsystemd/sd-netlink/netlink-types.h
+++ b/src/libsystemd/sd-netlink/netlink-types.h
@@ -1,9 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <errno.h>
-
-#include "sd-netlink.h"
+#include "forward.h"
 
 typedef enum NLAType {
         NETLINK_TYPE_UNSPEC,                    /* NLA_UNSPEC */
diff --git a/src/libsystemd/sd-netlink/netlink-util.c b/src/libsystemd/sd-netlink/netlink-util.c
index 2a56182750..3cb5820ff6 100644
--- a/src/libsystemd/sd-netlink/netlink-util.c
+++ b/src/libsystemd/sd-netlink/netlink-util.c
@@ -2,7 +2,9 @@
 
 #include "sd-netlink.h"
 
+#include "ether-addr-util.h"
 #include "fd-util.h"
+#include "hashmap.h"
 #include "iovec-util.h"
 #include "log.h"
 #include "memory-util.h"
@@ -10,6 +12,8 @@
 #include "netlink-util.h"
 #include "parse-util.h"
 #include "process-util.h"
+#include "socket-util.h"
+#include "string-util.h"
 #include "strv.h"
 
 static int parse_newlink_message(
diff --git a/src/libsystemd/sd-netlink/netlink-util.h b/src/libsystemd/sd-netlink/netlink-util.h
index 25b27291ba..a25e38d473 100644
--- a/src/libsystemd/sd-netlink/netlink-util.h
+++ b/src/libsystemd/sd-netlink/netlink-util.h
@@ -3,12 +3,8 @@
 
 #include <linux/rtnetlink.h>
 
-#include "sd-netlink.h"
-
-#include "ether-addr-util.h"
+#include "forward.h"
 #include "in-addr-util.h"
-#include "ordered-set.h"
-#include "socket-util.h"
 
 #define RTA_FLAGS(rta) ((rta)->rta_type & ~NLA_TYPE_MASK)
 #define RTA_TYPE(rta)  ((rta)->rta_type & NLA_TYPE_MASK)
diff --git a/src/libsystemd/sd-netlink/sd-netlink.c b/src/libsystemd/sd-netlink/sd-netlink.c
index d71a1c579c..57e5a65214 100644
--- a/src/libsystemd/sd-netlink/sd-netlink.c
+++ b/src/libsystemd/sd-netlink/sd-netlink.c
@@ -1,22 +1,28 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <linux/filter.h>
 #include <poll.h>
+#include <stdlib.h>
 
+#include "sd-event.h"
 #include "sd-netlink.h"
 
 #include "alloc-util.h"
+#include "errno-util.h"
 #include "fd-util.h"
 #include "hashmap.h"
 #include "io-util.h"
 #include "log.h"
-#include "macro.h"
 #include "netlink-genl.h"
 #include "netlink-internal.h"
 #include "netlink-slot.h"
 #include "netlink-util.h"
+#include "ordered-set.h"
+#include "prioq.h"
 #include "process-util.h"
 #include "socket-util.h"
 #include "string-util.h"
+#include "time-util.h"
 
 /* Some really high limit, to catch programming errors */
 #define REPLY_CALLBACKS_MAX UINT16_MAX
@@ -68,7 +74,7 @@ static int netlink_new(sd_netlink **ret) {
 
 int sd_netlink_open_fd(sd_netlink **ret, int fd) {
         _cleanup_(sd_netlink_unrefp) sd_netlink *nl = NULL;
-        int r, protocol;
+        int r, protocol = 0; /* Avoid maybe-uninitialized false positive */
 
         assert_return(ret, -EINVAL);
         assert_return(fd >= 0, -EBADF);
diff --git a/src/libsystemd/sd-netlink/test-netlink.c b/src/libsystemd/sd-netlink/test-netlink.c
index 252bb46b6e..ae29b438df 100644
--- a/src/libsystemd/sd-netlink/test-netlink.c
+++ b/src/libsystemd/sd-netlink/test-netlink.c
@@ -6,27 +6,27 @@
 #include <linux/l2tp.h>
 #include <linux/nl80211.h>
 #include <linux/unix_diag.h>
+#include <net/ethernet.h>
 #include <net/if.h>
-#include <netinet/ether.h>
 #include <netinet/in.h>
 #include <sys/stat.h>
 #include <unistd.h>
 
+#include "sd-event.h"
 #include "sd-netlink.h"
 
 #include "alloc-util.h"
-#include "ether-addr-util.h"
 #include "fd-util.h"
-#include "macro.h"
+#include "missing_network.h"
 #include "netlink-genl.h"
 #include "netlink-internal.h"
 #include "netlink-sock-diag.h"
 #include "netlink-util.h"
 #include "socket-util.h"
 #include "stdio-util.h"
-#include "string-util.h"
 #include "strv.h"
 #include "tests.h"
+#include "time-util.h"
 
 TEST(message_newlink_bridge) {
         _cleanup_(sd_netlink_unrefp) sd_netlink *rtnl = NULL;
diff --git a/src/libsystemd/sd-network/network-util.h b/src/libsystemd/sd-network/network-util.h
index 80b4cc3cd6..84ae36ad36 100644
--- a/src/libsystemd/sd-network/network-util.h
+++ b/src/libsystemd/sd-network/network-util.h
@@ -1,12 +1,10 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <errno.h>
-#include <netinet/in.h>
-#include <stdbool.h>
+#include <sys/socket.h>
 
 #include "constants.h"
-#include "macro.h"
+#include "forward.h"
 
 #define NETWORK_DIRS ((const char* const*) CONF_PATHS_STRV("systemd/network"))
 #define NETWORK_DIRS_NULSTR CONF_PATHS_NULSTR("systemd/network")
diff --git a/src/libsystemd/sd-network/sd-network.c b/src/libsystemd/sd-network/sd-network.c
index 60213c2fcf..9d95f8b5be 100644
--- a/src/libsystemd/sd-network/sd-network.c
+++ b/src/libsystemd/sd-network/sd-network.c
@@ -1,8 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
 #include <poll.h>
 #include <sys/inotify.h>
+#include <sys/stat.h>
+#include <unistd.h>
 
 #include "sd-network.h"
 
@@ -11,9 +12,7 @@
 #include "errno-util.h"
 #include "extract-word.h"
 #include "fd-util.h"
-#include "fs-util.h"
 #include "inotify-util.h"
-#include "macro.h"
 #include "parse-util.h"
 #include "stdio-util.h"
 #include "string-util.h"
diff --git a/src/libsystemd/sd-path/path-lookup.c b/src/libsystemd/sd-path/path-lookup.c
index a3b09208cb..3ddbda0e9f 100644
--- a/src/libsystemd/sd-path/path-lookup.c
+++ b/src/libsystemd/sd-path/path-lookup.c
@@ -1,21 +1,16 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
-#include <stdio.h>
 #include <stdlib.h>
 
 #include "alloc-util.h"
 #include "fs-util.h"
 #include "log.h"
-#include "macro.h"
-#include "nulstr-util.h"
 #include "path-lookup.h"
 #include "path-util.h"
 #include "stat-util.h"
 #include "string-util.h"
 #include "strv.h"
 #include "tmpfile-util.h"
-#include "user-util.h"
 
 int user_search_dirs(const char *suffix, char ***ret_config_dirs, char ***ret_data_dirs) {
         _cleanup_strv_free_ char **config_dirs = NULL, **data_dirs = NULL;
diff --git a/src/libsystemd/sd-path/path-lookup.h b/src/libsystemd/sd-path/path-lookup.h
index 1289e7ac6f..8457053339 100644
--- a/src/libsystemd/sd-path/path-lookup.h
+++ b/src/libsystemd/sd-path/path-lookup.h
@@ -1,10 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <stdbool.h>
-
 #include "sd-path.h"
 
+#include "forward.h"
 #include "runtime-scope.h"
 
 typedef enum LookupPathsFlags {
diff --git a/src/libsystemd/sd-path/sd-path.c b/src/libsystemd/sd-path/sd-path.c
index b8fd0ae0a7..f562e3a7ec 100644
--- a/src/libsystemd/sd-path/sd-path.c
+++ b/src/libsystemd/sd-path/sd-path.c
@@ -1,5 +1,7 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include <stdlib.h>
+
 #include "sd-path.h"
 
 #include "alloc-util.h"
@@ -7,7 +9,6 @@
 #include "fd-util.h"
 #include "fileio.h"
 #include "fs-util.h"
-#include "log.h"
 #include "network-util.h"
 #include "nulstr-util.h"
 #include "path-lookup.h"
diff --git a/src/libsystemd/sd-resolve/sd-resolve.c b/src/libsystemd/sd-resolve/sd-resolve.c
index 81052e7ec1..03ebfbb02c 100644
--- a/src/libsystemd/sd-resolve/sd-resolve.c
+++ b/src/libsystemd/sd-resolve/sd-resolve.c
@@ -1,18 +1,15 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
+#include <netdb.h>
 #include <poll.h>
 #include <pthread.h>
-#include <resolv.h>
 #include <signal.h>
-#include <stdint.h>
 #include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
-#include <sys/prctl.h>
 #include <threads.h>
 #include <unistd.h>
 
+#include "sd-event.h"
 #include "sd-resolve.h"
 
 #include "alloc-util.h"
@@ -24,7 +21,6 @@
 #include "list.h"
 #include "log.h"
 #include "memory-util.h"
-#include "missing_syscall.h"
 #include "process-util.h"
 #include "resolve-private.h"
 #include "socket-util.h"
diff --git a/src/libsystemd/sd-resolve/test-resolve.c b/src/libsystemd/sd-resolve/test-resolve.c
index 7a599925f4..18e29d9835 100644
--- a/src/libsystemd/sd-resolve/test-resolve.c
+++ b/src/libsystemd/sd-resolve/test-resolve.c
@@ -1,16 +1,14 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
 #include <arpa/inet.h>
-#include <errno.h>
-#include <net/if_arp.h>
+#include <netdb.h>
 #include <netinet/in.h>
-#include <resolv.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 #include "sd-resolve.h"
 
 #include "alloc-util.h"
-#include "macro.h"
 #include "socket-util.h"
 #include "string-util.h"
 #include "tests.h"
diff --git a/src/libsystemd/sd-varlink/sd-varlink-idl.c b/src/libsystemd/sd-varlink/sd-varlink-idl.c
index 1184bd5951..c0afc8c4e7 100644
--- a/src/libsystemd/sd-varlink/sd-varlink-idl.c
+++ b/src/libsystemd/sd-varlink/sd-varlink-idl.c
@@ -4,12 +4,13 @@
 
 #include "alloc-util.h"
 #include "ansi-color.h"
+#include "extract-word.h"
 #include "json-util.h"
 #include "log.h"
 #include "memstream-util.h"
 #include "set.h"
+#include "string-util.h"
 #include "strv.h"
-#include "terminal-util.h"
 #include "utf8.h"
 #include "varlink-idl-util.h"
 
diff --git a/src/libsystemd/sd-varlink/sd-varlink.c b/src/libsystemd/sd-varlink/sd-varlink.c
index d20b36704f..3255bf8ed3 100644
--- a/src/libsystemd/sd-varlink/sd-varlink.c
+++ b/src/libsystemd/sd-varlink/sd-varlink.c
@@ -1,16 +1,20 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <malloc.h>
 #include <poll.h>
+#include <stdlib.h>
+#include <unistd.h>
 
 #include "sd-daemon.h"
+#include "sd-event.h"
 #include "sd-varlink.h"
 
 #include "alloc-util.h"
 #include "errno-list.h"
 #include "errno-util.h"
 #include "escape.h"
+#include "extract-word.h"
 #include "fd-util.h"
+#include "format-util.h"
 #include "glyph-util.h"
 #include "hashmap.h"
 #include "io-util.h"
@@ -21,7 +25,6 @@
 #include "mkdir.h"
 #include "path-util.h"
 #include "process-util.h"
-#include "set.h"
 #include "socket-util.h"
 #include "string-table.h"
 #include "string-util.h"
diff --git a/src/libsystemd/sd-varlink/varlink-idl-util.h b/src/libsystemd/sd-varlink/varlink-idl-util.h
index 990eb804a9..0640a26995 100644
--- a/src/libsystemd/sd-varlink/varlink-idl-util.h
+++ b/src/libsystemd/sd-varlink/varlink-idl-util.h
@@ -4,7 +4,7 @@
 #include "sd-varlink.h"
 #include "sd-varlink-idl.h"
 
-#include "memory-util.h"
+#include "forward.h"
 
 bool varlink_idl_field_name_is_valid(const char *name);
 bool varlink_idl_symbol_name_is_valid(const char *name);
diff --git a/src/libsystemd/sd-varlink/varlink-internal.h b/src/libsystemd/sd-varlink/varlink-internal.h
index 5ff233f210..a163f81061 100644
--- a/src/libsystemd/sd-varlink/varlink-internal.h
+++ b/src/libsystemd/sd-varlink/varlink-internal.h
@@ -3,11 +3,10 @@
 
 #include <sys/socket.h>
 
-#include "sd-event.h"
 #include "sd-varlink.h"
 
-#include "hashmap.h"
 #include "list.h"
+#include "forward.h"
 
 typedef enum VarlinkState {
         /* Client side states */
diff --git a/src/libsystemd/sd-varlink/varlink-util.c b/src/libsystemd/sd-varlink/varlink-util.c
index 438ef6bd7a..dfefe08862 100644
--- a/src/libsystemd/sd-varlink/varlink-util.c
+++ b/src/libsystemd/sd-varlink/varlink-util.c
@@ -3,8 +3,9 @@
 #include "alloc-util.h"
 #include "errno-util.h"
 #include "log.h"
+#include "pidref.h"
+#include "set.h"
 #include "string-util.h"
-#include "varlink-internal.h"
 #include "varlink-util.h"
 #include "version.h"
 
diff --git a/src/libsystemd/sd-varlink/varlink-util.h b/src/libsystemd/sd-varlink/varlink-util.h
index 449b962767..3a340b2216 100644
--- a/src/libsystemd/sd-varlink/varlink-util.h
+++ b/src/libsystemd/sd-varlink/varlink-util.h
@@ -3,8 +3,7 @@
 
 #include "sd-varlink.h"
 
-#include "pidref.h"
-#include "set.h"
+#include "forward.h"
 
 int varlink_get_peer_pidref(sd_varlink *v, PidRef *ret);
 
diff --git a/src/systemd/_sd-common.h b/src/systemd/_sd-common.h
index 00537eaf16..bf2e20e201 100644
--- a/src/systemd/_sd-common.h
+++ b/src/systemd/_sd-common.h
@@ -17,6 +17,13 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
+#include <errno.h>
+#include <inttypes.h>
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <sys/types.h>
+
 /* This is a private header; never even think of including this directly! */
 
 #if defined(__INCLUDE_LEVEL__) && __INCLUDE_LEVEL__ <= 1 && !defined(__COVERITY__) && !defined(__clang_analyzer__)
diff --git a/src/systemd/sd-bus-vtable.h b/src/systemd/sd-bus-vtable.h
index 4ab5cf674f..5c11ca8ae5 100644
--- a/src/systemd/sd-bus-vtable.h
+++ b/src/systemd/sd-bus-vtable.h
@@ -17,9 +17,6 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <stddef.h>
-#include <stdint.h>
-
 #include "_sd-common.h"
 #include "sd-bus-protocol.h"
 
diff --git a/src/systemd/sd-bus.h b/src/systemd/sd-bus.h
index 77cb834121..8842aa63ec 100644
--- a/src/systemd/sd-bus.h
+++ b/src/systemd/sd-bus.h
@@ -17,10 +17,7 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-#include <stdarg.h>
 #include <stdio.h>
-#include <sys/types.h>
 #include <sys/uio.h>
 
 #include "_sd-common.h"
diff --git a/src/systemd/sd-daemon.h b/src/systemd/sd-daemon.h
index a18a9211b9..932e8ea53e 100644
--- a/src/systemd/sd-daemon.h
+++ b/src/systemd/sd-daemon.h
@@ -17,9 +17,7 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
 #include <sys/socket.h>
-#include <sys/types.h>
 
 #include "_sd-common.h"
 
diff --git a/src/systemd/sd-device.h b/src/systemd/sd-device.h
index 71d8c89983..05e977c5ce 100644
--- a/src/systemd/sd-device.h
+++ b/src/systemd/sd-device.h
@@ -17,11 +17,8 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <errno.h>
-#include <inttypes.h>
 #include <sys/stat.h>
 #include <sys/sysmacros.h>
-#include <sys/types.h>
 
 #include "_sd-common.h"
 #include "sd-event.h"
diff --git a/src/systemd/sd-dhcp-client-id.h b/src/systemd/sd-dhcp-client-id.h
index 404c01b1eb..21a237af0a 100644
--- a/src/systemd/sd-dhcp-client-id.h
+++ b/src/systemd/sd-dhcp-client-id.h
@@ -17,15 +17,12 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-#include <sys/types.h>
-
 #include "_sd-common.h"
-#include "sd-dhcp-duid.h"
 
 _SD_BEGIN_DECLARATIONS;
 
 typedef struct sd_dhcp_client_id sd_dhcp_client_id;
+typedef struct sd_dhcp_duid sd_dhcp_duid;
 
 int sd_dhcp_client_id_new(sd_dhcp_client_id **ret);
 sd_dhcp_client_id* sd_dhcp_client_id_free(sd_dhcp_client_id *client_id);
diff --git a/src/systemd/sd-dhcp-client.h b/src/systemd/sd-dhcp-client.h
index 0fb87e2684..4e288f0828 100644
--- a/src/systemd/sd-dhcp-client.h
+++ b/src/systemd/sd-dhcp-client.h
@@ -19,21 +19,20 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-#include <net/ethernet.h>
-#include <netinet/in.h>
 #include <stdbool.h>
-#include <sys/types.h>
 
 #include "_sd-common.h"
-#include "sd-device.h"
-#include "sd-dhcp-client-id.h"
-#include "sd-dhcp-lease.h"
-#include "sd-dhcp-option.h"
-#include "sd-event.h"
 
 _SD_BEGIN_DECLARATIONS;
 
+struct in_addr;
+
+typedef struct sd_device sd_device;
+typedef struct sd_dhcp_client_id sd_dhcp_client_id;
+typedef struct sd_dhcp_lease sd_dhcp_lease;
+typedef struct sd_dhcp_option sd_dhcp_option;
+typedef struct sd_event sd_event;
+
 enum {
         SD_DHCP_CLIENT_EVENT_STOP               = 0,
         SD_DHCP_CLIENT_EVENT_IP_ACQUIRE         = 1,
diff --git a/src/systemd/sd-dhcp-duid.h b/src/systemd/sd-dhcp-duid.h
index 555b40e9d8..6451c7fcae 100644
--- a/src/systemd/sd-dhcp-duid.h
+++ b/src/systemd/sd-dhcp-duid.h
@@ -17,9 +17,6 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-#include <sys/types.h>
-
 #include "_sd-common.h"
 
 _SD_BEGIN_DECLARATIONS;
diff --git a/src/systemd/sd-dhcp-lease.h b/src/systemd/sd-dhcp-lease.h
index fa5772019c..4bdfb5bf2d 100644
--- a/src/systemd/sd-dhcp-lease.h
+++ b/src/systemd/sd-dhcp-lease.h
@@ -18,17 +18,14 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <errno.h>
-#include <inttypes.h>
-#include <net/ethernet.h>
-#include <netinet/in.h>
-#include <sys/types.h>
-
 #include "_sd-common.h"
-#include "sd-dhcp-client-id.h"
 
 _SD_BEGIN_DECLARATIONS;
 
+struct in_addr;
+struct in6_addr;
+
+typedef struct sd_dhcp_client_id sd_dhcp_client_id;
 typedef struct sd_dhcp_lease sd_dhcp_lease;
 typedef struct sd_dhcp_route sd_dhcp_route;
 typedef struct sd_dns_resolver sd_dns_resolver;
diff --git a/src/systemd/sd-dhcp-option.h b/src/systemd/sd-dhcp-option.h
index 14141da1db..bfb5be8b2b 100644
--- a/src/systemd/sd-dhcp-option.h
+++ b/src/systemd/sd-dhcp-option.h
@@ -17,11 +17,8 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-#include <sys/types.h>
-
 #include "_sd-common.h"
-#include "sd-dhcp-protocol.h"
+#include "sd-dhcp-protocol.h"   /* IWYU pragma: export */
 
 _SD_BEGIN_DECLARATIONS;
 
diff --git a/src/systemd/sd-dhcp-server.h b/src/systemd/sd-dhcp-server.h
index 0ef4d132cf..d6940ac7f8 100644
--- a/src/systemd/sd-dhcp-server.h
+++ b/src/systemd/sd-dhcp-server.h
@@ -18,16 +18,15 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
 #include <netinet/in.h>
 
 #include "_sd-common.h"
 #include "sd-dhcp-lease.h"
-#include "sd-dhcp-option.h"
-#include "sd-event.h"
 
 _SD_BEGIN_DECLARATIONS;
 
+typedef struct sd_event sd_event;
+typedef struct sd_dhcp_option sd_dhcp_option;
 typedef struct sd_dhcp_server sd_dhcp_server;
 
 enum {
diff --git a/src/systemd/sd-dhcp6-client.h b/src/systemd/sd-dhcp6-client.h
index 6054dc4432..b388acc137 100644
--- a/src/systemd/sd-dhcp6-client.h
+++ b/src/systemd/sd-dhcp6-client.h
@@ -19,19 +19,18 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-#include <net/ethernet.h>
-#include <sys/types.h>
-
 #include "_sd-common.h"
-#include "sd-device.h"
-#include "sd-dhcp-duid.h"
-#include "sd-dhcp6-lease.h"
-#include "sd-dhcp6-option.h"
-#include "sd-event.h"
 
 _SD_BEGIN_DECLARATIONS;
 
+struct in6_addr;
+
+typedef struct sd_dhcp_duid sd_dhcp_duid;
+typedef struct sd_dhcp6_option sd_dhcp6_option;
+typedef struct sd_dhcp6_lease sd_dhcp6_lease;
+typedef struct sd_device sd_device;
+typedef struct sd_event sd_event;
+
 enum {
         SD_DHCP6_CLIENT_EVENT_STOP                      = 0,
         SD_DHCP6_CLIENT_EVENT_RESEND_EXPIRE             = 10,
diff --git a/src/systemd/sd-dhcp6-lease.h b/src/systemd/sd-dhcp6-lease.h
index 5d082b0cbe..766adf3121 100644
--- a/src/systemd/sd-dhcp6-lease.h
+++ b/src/systemd/sd-dhcp6-lease.h
@@ -19,16 +19,15 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-#include <netinet/in.h>
-#include <sys/types.h>
 
 #include "_sd-common.h"
-#include "sd-dhcp6-option.h"
 
 _SD_BEGIN_DECLARATIONS;
 
+struct in6_addr;
+
 typedef struct sd_dhcp6_lease sd_dhcp6_lease;
+typedef struct sd_dhcp6_option sd_dhcp6_option;
 typedef struct sd_dns_resolver sd_dns_resolver;
 
 int sd_dhcp6_lease_get_timestamp(sd_dhcp6_lease *lease, clockid_t clock, uint64_t *ret);
diff --git a/src/systemd/sd-dhcp6-option.h b/src/systemd/sd-dhcp6-option.h
index 69f3eaa39d..b86441d93f 100644
--- a/src/systemd/sd-dhcp6-option.h
+++ b/src/systemd/sd-dhcp6-option.h
@@ -17,11 +17,8 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-#include <sys/types.h>
-
 #include "_sd-common.h"
-#include "sd-dhcp6-protocol.h"
+#include "sd-dhcp6-protocol.h"  /* IWYU pragma: export */
 
 _SD_BEGIN_DECLARATIONS;
 
diff --git a/src/systemd/sd-event.h b/src/systemd/sd-event.h
index 4d89b3472c..ac98b67da4 100644
--- a/src/systemd/sd-event.h
+++ b/src/systemd/sd-event.h
@@ -17,12 +17,10 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
 #include <signal.h>
 #include <sys/epoll.h>
 #include <sys/inotify.h>
 #include <sys/signalfd.h>
-#include <sys/types.h>
 #include <sys/wait.h>
 #include <time.h>
 
diff --git a/src/systemd/sd-id128.h b/src/systemd/sd-id128.h
index 7be690400d..da095a1e17 100644
--- a/src/systemd/sd-id128.h
+++ b/src/systemd/sd-id128.h
@@ -17,8 +17,6 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-#include <stdarg.h>
 #include <string.h>
 
 #include "_sd-common.h"
diff --git a/src/systemd/sd-ipv4acd.h b/src/systemd/sd-ipv4acd.h
index 33879af516..bcc5222aec 100644
--- a/src/systemd/sd-ipv4acd.h
+++ b/src/systemd/sd-ipv4acd.h
@@ -18,15 +18,17 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <net/ethernet.h>
-#include <netinet/in.h>
 #include <stdbool.h>
 
 #include "_sd-common.h"
-#include "sd-event.h"
 
 _SD_BEGIN_DECLARATIONS;
 
+struct ether_addr;
+struct in_addr;
+
+typedef struct sd_event sd_event;
+
 enum {
         SD_IPV4ACD_EVENT_STOP           = 0,
         SD_IPV4ACD_EVENT_BIND           = 1,
diff --git a/src/systemd/sd-ipv4ll.h b/src/systemd/sd-ipv4ll.h
index 6c687fef20..351cce0c2f 100644
--- a/src/systemd/sd-ipv4ll.h
+++ b/src/systemd/sd-ipv4ll.h
@@ -19,14 +19,15 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <net/ethernet.h>
-#include <netinet/in.h>
-
 #include "_sd-common.h"
-#include "sd-event.h"
 
 _SD_BEGIN_DECLARATIONS;
 
+struct ether_addr;
+struct in_addr;
+
+typedef struct sd_event sd_event;
+
 enum {
         SD_IPV4LL_EVENT_STOP            = 0,
         SD_IPV4LL_EVENT_BIND            = 1,
diff --git a/src/systemd/sd-journal.h b/src/systemd/sd-journal.h
index ca062ca681..ec1568904e 100644
--- a/src/systemd/sd-journal.h
+++ b/src/systemd/sd-journal.h
@@ -17,9 +17,6 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-#include <stdarg.h>
-#include <sys/types.h>
 #include <sys/uio.h>
 #include <syslog.h>
 
diff --git a/src/systemd/sd-json.h b/src/systemd/sd-json.h
index 754ce73db8..fabec8a7a4 100644
--- a/src/systemd/sd-json.h
+++ b/src/systemd/sd-json.h
@@ -17,10 +17,7 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <errno.h>
 #include <fcntl.h>
-#include <inttypes.h>
-#include <stddef.h>
 #include <stdio.h>
 
 #include "_sd-common.h"
diff --git a/src/systemd/sd-lldp-rx.h b/src/systemd/sd-lldp-rx.h
index d4e135512e..552ab81329 100644
--- a/src/systemd/sd-lldp-rx.h
+++ b/src/systemd/sd-lldp-rx.h
@@ -17,17 +17,14 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <errno.h>
-#include <inttypes.h>
-#include <net/ethernet.h>
-#include <sys/types.h>
-
 #include "_sd-common.h"
-#include "sd-event.h"
-#include "sd-lldp.h"
+#include "sd-lldp.h"    /* IWYU pragma: export*/
 
 _SD_BEGIN_DECLARATIONS;
 
+struct ether_addr;
+
+typedef struct sd_event sd_event;
 typedef struct sd_lldp_rx sd_lldp_rx;
 typedef struct sd_lldp_neighbor sd_lldp_neighbor;
 
diff --git a/src/systemd/sd-lldp-tx.h b/src/systemd/sd-lldp-tx.h
index 73b9f2ad3c..107292027d 100644
--- a/src/systemd/sd-lldp-tx.h
+++ b/src/systemd/sd-lldp-tx.h
@@ -17,17 +17,14 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <errno.h>
-#include <inttypes.h>
-#include <net/ethernet.h>
-#include <sys/types.h>
-
 #include "_sd-common.h"
-#include "sd-event.h"
-#include "sd-lldp.h"
+#include "sd-lldp.h"    /* IWYU pragma: export*/
 
 _SD_BEGIN_DECLARATIONS;
 
+struct ether_addr;
+
+typedef struct sd_event sd_event;
 typedef struct sd_lldp_tx sd_lldp_tx;
 
 __extension__ typedef enum _SD_ENUM_TYPE_S64(sd_lldp_multicast_mode_t) {
diff --git a/src/systemd/sd-lldp.h b/src/systemd/sd-lldp.h
index 4069c5b299..7c68dc6e33 100644
--- a/src/systemd/sd-lldp.h
+++ b/src/systemd/sd-lldp.h
@@ -17,8 +17,6 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-
 #include "_sd-common.h"
 
 _SD_BEGIN_DECLARATIONS;
diff --git a/src/systemd/sd-login.h b/src/systemd/sd-login.h
index cb80431b16..dbf69c2106 100644
--- a/src/systemd/sd-login.h
+++ b/src/systemd/sd-login.h
@@ -17,9 +17,6 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-#include <sys/types.h>
-
 #include "_sd-common.h"
 
 /*
diff --git a/src/systemd/sd-ndisc-neighbor.h b/src/systemd/sd-ndisc-neighbor.h
index 2ea033741f..750f048b87 100644
--- a/src/systemd/sd-ndisc-neighbor.h
+++ b/src/systemd/sd-ndisc-neighbor.h
@@ -17,16 +17,13 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-#include <net/ethernet.h>
-#include <netinet/in.h>
-#include <sys/types.h>
-#include <time.h>
-
 #include "_sd-common.h"
 
 _SD_BEGIN_DECLARATIONS;
 
+struct in6_addr;
+struct ether_addr;
+
 typedef struct sd_ndisc_neighbor sd_ndisc_neighbor;
 
 sd_ndisc_neighbor *sd_ndisc_neighbor_ref(sd_ndisc_neighbor *na);
diff --git a/src/systemd/sd-ndisc-redirect.h b/src/systemd/sd-ndisc-redirect.h
index 60b43f769d..6c3a7b9f78 100644
--- a/src/systemd/sd-ndisc-redirect.h
+++ b/src/systemd/sd-ndisc-redirect.h
@@ -17,17 +17,14 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-#include <net/ethernet.h>
-#include <netinet/in.h>
-#include <netinet/ip6.h>
-#include <sys/types.h>
-#include <time.h>
-
 #include "_sd-common.h"
 
 _SD_BEGIN_DECLARATIONS;
 
+struct ether_addr;
+struct in6_addr;
+struct ip6_hdr;
+
 typedef struct sd_ndisc_redirect sd_ndisc_redirect;
 
 sd_ndisc_redirect* sd_ndisc_redirect_ref(sd_ndisc_redirect *na);
diff --git a/src/systemd/sd-ndisc-router-solicit.h b/src/systemd/sd-ndisc-router-solicit.h
index ff8c903af8..819f3b874e 100644
--- a/src/systemd/sd-ndisc-router-solicit.h
+++ b/src/systemd/sd-ndisc-router-solicit.h
@@ -17,13 +17,11 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-#include <net/ethernet.h>
-#include <netinet/in.h>
-#include <sys/types.h>
-
 #include "_sd-common.h"
 
+struct in6_addr;
+struct ether_addr;
+
 _SD_BEGIN_DECLARATIONS;
 
 typedef struct sd_ndisc_router_solicit sd_ndisc_router_solicit;
diff --git a/src/systemd/sd-ndisc-router.h b/src/systemd/sd-ndisc-router.h
index a7f1365381..823f3aede8 100644
--- a/src/systemd/sd-ndisc-router.h
+++ b/src/systemd/sd-ndisc-router.h
@@ -17,16 +17,13 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-#include <net/ethernet.h>
-#include <netinet/in.h>
-#include <sys/types.h>
-#include <time.h>
-
 #include "_sd-common.h"
 
 _SD_BEGIN_DECLARATIONS;
 
+struct ether_addr;
+struct in6_addr;
+
 typedef struct sd_ndisc_router sd_ndisc_router;
 typedef struct sd_dns_resolver sd_dns_resolver;
 
diff --git a/src/systemd/sd-ndisc.h b/src/systemd/sd-ndisc.h
index a8f8c47b68..57cb32ef75 100644
--- a/src/systemd/sd-ndisc.h
+++ b/src/systemd/sd-ndisc.h
@@ -19,21 +19,18 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <errno.h>
-#include <inttypes.h>
-#include <net/ethernet.h>
-#include <netinet/in.h>
-#include <sys/types.h>
-
 #include "_sd-common.h"
-#include "sd-event.h"
-#include "sd-ndisc-neighbor.h"
-#include "sd-ndisc-protocol.h"
-#include "sd-ndisc-redirect.h"
-#include "sd-ndisc-router.h"
+#include "sd-ndisc-neighbor.h"  /* IWYU pragma: export */
+#include "sd-ndisc-protocol.h"  /* IWYU pragma: export */
+#include "sd-ndisc-redirect.h"  /* IWYU pragma: export */
+#include "sd-ndisc-router.h"    /* IWYU pragma: export */
 
 _SD_BEGIN_DECLARATIONS;
 
+struct ether_addr;
+struct in6_addr;
+
+typedef struct sd_event sd_event;
 typedef struct sd_ndisc sd_ndisc;
 
 __extension__ typedef enum _SD_ENUM_TYPE_S64(sd_ndisc_event_t) {
diff --git a/src/systemd/sd-netlink.h b/src/systemd/sd-netlink.h
index 5f8f143db1..ea7a5cf69d 100644
--- a/src/systemd/sd-netlink.h
+++ b/src/systemd/sd-netlink.h
@@ -17,19 +17,22 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <errno.h>
-#include <inttypes.h>
-#include <linux/filter.h>
-#include <linux/neighbour.h>
-#include <linux/rtnetlink.h>
-#include <net/ethernet.h>
-#include <netinet/in.h>
+#include <linux/rtnetlink.h> /* IWYU pragma: export */
 
 #include "_sd-common.h"
-#include "sd-event.h"
 
 _SD_BEGIN_DECLARATIONS;
 
+struct ether_addr;
+struct in_addr;
+struct in6_addr;
+struct sockaddr_in;
+struct sockaddr_in6;
+struct sock_filter;
+struct ifa_cacheinfo;
+
+typedef struct sd_event sd_event;
+
 typedef struct sd_netlink sd_netlink;
 typedef struct sd_netlink_message sd_netlink_message;
 typedef struct sd_netlink_slot sd_netlink_slot;
diff --git a/src/systemd/sd-network.h b/src/systemd/sd-network.h
index d310d238d0..2a9261b246 100644
--- a/src/systemd/sd-network.h
+++ b/src/systemd/sd-network.h
@@ -17,10 +17,6 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-
 #include "_sd-common.h"
 
 /*
@@ -44,6 +40,8 @@
 
 _SD_BEGIN_DECLARATIONS;
 
+struct stat;
+
 /* Get overall operational state
  * Possible states: down, up, dormant, carrier, degraded, routable
  * Possible return codes:
diff --git a/src/systemd/sd-path.h b/src/systemd/sd-path.h
index bd3a60150c..5d5bdfe206 100644
--- a/src/systemd/sd-path.h
+++ b/src/systemd/sd-path.h
@@ -17,8 +17,6 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-
 #include "_sd-common.h"
 
 _SD_BEGIN_DECLARATIONS;
diff --git a/src/systemd/sd-radv.h b/src/systemd/sd-radv.h
index 6c1c4154e2..8823049b52 100644
--- a/src/systemd/sd-radv.h
+++ b/src/systemd/sd-radv.h
@@ -19,18 +19,14 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <inttypes.h>
-#include <net/ethernet.h>
-#include <netinet/in.h>
-#include <sys/types.h>
-
 #include "_sd-common.h"
-#include "sd-event.h"
-#include "sd-ndisc-protocol.h"
-#include "sd-ndisc-router-solicit.h"
 
 _SD_BEGIN_DECLARATIONS;
 
+struct ether_addr;
+struct in6_addr;
+
+typedef struct sd_event sd_event;
 typedef struct sd_radv sd_radv;
 
 int sd_radv_new(sd_radv **ret);
diff --git a/src/systemd/sd-resolve.h b/src/systemd/sd-resolve.h
index 5378040684..ad05bd7e40 100644
--- a/src/systemd/sd-resolve.h
+++ b/src/systemd/sd-resolve.h
@@ -22,16 +22,16 @@
 #define _GNU_SOURCE 1
 #endif
 
-#include <inttypes.h>
-#include <netdb.h>
 #include <sys/socket.h>
-#include <sys/types.h>
 
 #include "_sd-common.h"
-#include "sd-event.h"
 
 _SD_BEGIN_DECLARATIONS;
 
+struct addrinfo;
+
+typedef struct sd_event sd_event;
+
 /* An opaque sd-resolve session structure */
 typedef struct sd_resolve sd_resolve;
 
diff --git a/src/systemd/sd-varlink-idl.h b/src/systemd/sd-varlink-idl.h
index 0fe49b8677..c0d49716b0 100644
--- a/src/systemd/sd-varlink-idl.h
+++ b/src/systemd/sd-varlink-idl.h
@@ -17,7 +17,6 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <errno.h>
 #include <stdio.h>
 
 #include "_sd-common.h"
diff --git a/src/systemd/sd-varlink.h b/src/systemd/sd-varlink.h
index c584112bfa..d1f5087492 100644
--- a/src/systemd/sd-varlink.h
+++ b/src/systemd/sd-varlink.h
@@ -17,9 +17,6 @@
   along with systemd; If not, see <https://www.gnu.org/licenses/>.
 ***/
 
-#include <stdarg.h>
-#include <sys/types.h>
-
 #include "_sd-common.h"
 #include "sd-event.h"
 #include "sd-json.h"