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resolved: move packet rewinder initalization inline

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There is no functional change, but this reduces the risk that
in some future refactoring we'll forget the do the initialization in all
execution paths.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek
2021-11-23 12:30:30 +01:00
parent a33bc79b99
commit 0c4f37f0fb
1 changed files with 39 additions and 52 deletions
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91
src/resolve/resolved-dns-packet.c
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@@ -29,8 +29,11 @@ static void rewind_dns_packet(DnsPacketRewinder *rewinder) {
dns_packet_rewind(rewinder->packet, rewinder->saved_rindex);
}
#define INIT_REWINDER(rewinder, p) do { rewinder.packet = p; rewinder.saved_rindex = p->rindex; } while (0)
#define CANCEL_REWINDER(rewinder) do { rewinder.packet = NULL; } while (0)
#define REWINDER_INIT(p) { \
.packet = (p), \
.saved_rindex = (p)->rindex, \
}
#define CANCEL_REWINDER(rewinder) do { (rewinder).packet = NULL; } while (0)
int dns_packet_new(
DnsPacket **ret,
@@ -1373,15 +1376,14 @@ int dns_packet_read_uint32(DnsPacket *p, uint32_t *ret, size_t *start) {
}
int dns_packet_read_string(DnsPacket *p, char **ret, size_t *start) {
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
assert(p);
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder = REWINDER_INIT(p);
const void *d;
char *t;
uint8_t c;
int r;
assert(p);
INIT_REWINDER(rewinder, p);
r = dns_packet_read_uint8(p, &c, NULL);
if (r < 0)
return r;
@@ -1412,13 +1414,12 @@ int dns_packet_read_string(DnsPacket *p, char **ret, size_t *start) {
}
int dns_packet_read_raw_string(DnsPacket *p, const void **ret, size_t *size, size_t *start) {
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
assert(p);
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder = REWINDER_INIT(p);
uint8_t c;
int r;
assert(p);
INIT_REWINDER(rewinder, p);
r = dns_packet_read_uint8(p, &c, NULL);
if (r < 0)
return r;
@@ -1442,18 +1443,15 @@ int dns_packet_read_name(
bool allow_compression,
size_t *ret_start) {
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
size_t after_rindex = 0, jump_barrier;
assert(p);
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder = REWINDER_INIT(p);
size_t after_rindex = 0, jump_barrier = p->rindex;
_cleanup_free_ char *name = NULL;
bool first = true;
size_t n = 0;
int r;
assert(p);
INIT_REWINDER(rewinder, p);
jump_barrier = p->rindex;
if (p->refuse_compression)
allow_compression = false;
@@ -1530,19 +1528,17 @@ int dns_packet_read_name(
}
static int dns_packet_read_type_window(DnsPacket *p, Bitmap **types, size_t *start) {
uint8_t window;
uint8_t length;
assert(p);
assert(types);
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder = REWINDER_INIT(p);
uint8_t window, length;
const uint8_t *bitmap;
uint8_t bit = 0;
unsigned i;
bool found = false;
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
int r;
assert(p);
assert(types);
INIT_REWINDER(rewinder, p);
r = bitmap_ensure_allocated(types);
if (r < 0)
return r;
@@ -1600,11 +1596,9 @@ static int dns_packet_read_type_window(DnsPacket *p, Bitmap **types, size_t *sta
}
static int dns_packet_read_type_windows(DnsPacket *p, Bitmap **types, size_t size, size_t *start) {
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder = REWINDER_INIT(p);
int r;
INIT_REWINDER(rewinder, p);
while (p->rindex < rewinder.saved_rindex + size) {
r = dns_packet_read_type_window(p, types, NULL);
if (r < 0)
@@ -1631,15 +1625,14 @@ int dns_packet_read_key(
bool *ret_cache_flush_or_qu,
size_t *ret_start) {
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
assert(p);
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder = REWINDER_INIT(p);
_cleanup_free_ char *name = NULL;
bool cache_flush_or_qu = false;
uint16_t class, type;
int r;
assert(p);
INIT_REWINDER(rewinder, p);
r = dns_packet_read_name(p, &name, true, NULL);
if (r < 0)
return r;
@@ -1693,18 +1686,16 @@ int dns_packet_read_rr(
bool *ret_cache_flush,
size_t *ret_start) {
assert(p);
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder = REWINDER_INIT(p);
_cleanup_(dns_resource_record_unrefp) DnsResourceRecord *rr = NULL;
_cleanup_(dns_resource_key_unrefp) DnsResourceKey *key = NULL;
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
size_t offset;
uint16_t rdlength;
bool cache_flush;
int r;
assert(p);
INIT_REWINDER(rewinder, p);
r = dns_packet_read_key(p, &key, &cache_flush, NULL);
if (r < 0)
return r;
@@ -2390,15 +2381,16 @@ static int dns_packet_extract_answer(DnsPacket *p, DnsAnswer **ret_answer) {
}
int dns_packet_extract(DnsPacket *p) {
_cleanup_(dns_question_unrefp) DnsQuestion *question = NULL;
_cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder = {};
int r;
assert(p);
if (p->extracted)
return 0;
INIT_REWINDER(rewinder, p);
_cleanup_(dns_question_unrefp) DnsQuestion *question = NULL;
_cleanup_(dns_answer_unrefp) DnsAnswer *answer = NULL;
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder = REWINDER_INIT(p);
int r;
dns_packet_rewind(p, DNS_PACKET_HEADER_SIZE);
r = dns_packet_extract_question(p, &question);
@@ -2417,7 +2409,6 @@ int dns_packet_extract(DnsPacket *p) {
p->question = TAKE_PTR(question);
p->answer = TAKE_PTR(answer);
p->extracted = true;
/* no CANCEL, always rewind */
@@ -2466,14 +2457,12 @@ int dns_packet_patch_max_udp_size(DnsPacket *p, uint16_t max_udp_size) {
}
static int patch_rr(DnsPacket *p, usec_t age) {
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder;
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder = REWINDER_INIT(p);
size_t ttl_index;
uint32_t ttl;
uint16_t type, rdlength;
int r;
INIT_REWINDER(rewinder, p);
/* Patches the RR at the current rindex, subtracts the specified time from the TTL */
r = dns_packet_read_name(p, NULL, true, NULL);
@@ -2510,22 +2499,20 @@ static int patch_rr(DnsPacket *p, usec_t age) {
}
int dns_packet_patch_ttls(DnsPacket *p, usec_t timestamp) {
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder = {};
unsigned i, n;
usec_t k;
int r;
assert(p);
assert(timestamp_is_set(timestamp));
/* Adjusts all TTLs in the packet by subtracting the time difference between now and the specified timestamp */
_cleanup_(rewind_dns_packet) DnsPacketRewinder rewinder = REWINDER_INIT(p);
unsigned i, n;
usec_t k;
int r;
k = now(clock_boottime_or_monotonic());
assert(k >= timestamp);
k -= timestamp;
INIT_REWINDER(rewinder, p);
dns_packet_rewind(p, DNS_PACKET_HEADER_SIZE);
n = DNS_PACKET_QDCOUNT(p);