Merge pull request #29588 from keszybz/net-naming-scheme-255

Untangle the net-naming-scheme mess with SR-IOV-R "representor" information

NEWS

@@ -60,6 +60,13 @@ CHANGES WITH 255 in spe:
           is now dropped, as it never worked, hence it should not be used by
           anyone.
 
+        * The predictable network interface naming logic is extended to include
+          the SR-IOV-R "representor" information in network interface names.
+          This feature was intended for v254, but even though the code was
+          merged, the part that actually enabled the feature was forgotten.
+          It is now enabled by default and is part of the new "v255" naming
+          scheme.
+
         Changes in systemd-analyze:
 
         * "systemd-analyze plot" has gained tooltips on each unit name with
@@ -576,8 +583,11 @@ CHANGES WITH 254:
           selects the default value of the per-network setting of the same
           name.
 
-        * The predictable network interface naming logic will now include
-          SR-IOV-R "representor" information in network interface names.
+        * The predictable network interface naming logic was extended to
+          include SR-IOV-R "representor" information in network interface
+          names. Unfortunately, this feature was not enabled by default and can
+          only be enabled at compilation time by setting
+          -Ddefault-net-naming-scheme=v254.
 
         * The DHCPv4 + DHCPv6 + IPv6 RA logic in networkd gained support for
           the RFC8910 captive portal option.

man/systemd.net-naming-scheme.xml

@@ -505,13 +505,23 @@
         <varlistentry>
           <term><constant>v254</constant></term>
 
-          <listitem><para>Naming was changed for SR-IOV virtual device representors.</para>
+          <listitem><para>Naming was changed for SR-IOV virtual device representors, optionally settable at
+          compilation time. The <literal>r<replaceable>slot</replaceable></literal> suffix was added to
+          differentiate SR-IOV virtual device representors attached to a single physical device interface.
+          Because of a mistake, this scheme was <emphasis>not the the default scheme for systemd version
+          254</emphasis>.</para>
 
-          <para>The <literal>r<replaceable>slot</replaceable></literal> suffix was added to differentiate SR-IOV
-          virtual device representors attached to a single physical device interface.
-          </para>
+          <xi:include href="version-info.xml" xpointer="v255"/>
+          </listitem>
+        </varlistentry>
 
-          <xi:include href="version-info.xml" xpointer="v254"/>
+        <varlistentry>
+          <term><constant>v255</constant></term>
+
+          <listitem><para>Naming was changed for SR-IOV virtual device representors to enable the
+          change introduced in <constant>v254</constant> by default.</para>
+
+          <xi:include href="version-info.xml" xpointer="v255"/>
           </listitem>
         </varlistentry>
 

meson.build

@@ -767,10 +767,12 @@ conf.set('EXTRA_NET_NAMING_SCHEMES', ' '.join(extra_net_naming_schemes))
 conf.set('EXTRA_NET_NAMING_MAP', ' '.join(extra_net_naming_map))
 
 default_net_naming_scheme = get_option('default-net-naming-scheme')
-conf.set_quoted('DEFAULT_NET_NAMING_SCHEME', default_net_naming_scheme)
+conf.set_quoted('DEFAULT_NET_NAMING_SCHEME', default_net_naming_scheme,
+                description : 'Default naming scheme as a string')
 if default_net_naming_scheme != 'latest'
-        conf.set('_DEFAULT_NET_NAMING_SCHEME_TEST',
-                 'NAMING_' + default_net_naming_scheme.underscorify().to_upper())
+        conf.set('_DEFAULT_NET_NAMING_SCHEME',
+                 'NAMING_' + default_net_naming_scheme.underscorify().to_upper(),
+                 description : 'Default naming scheme as a constant')
 endif
 
 time_epoch = get_option('time-epoch')

src/shared/netif-naming-scheme.c

@@ -6,13 +6,6 @@
 #include "string-util.h"
 #include "string-table.h"
 
-#ifdef _DEFAULT_NET_NAMING_SCHEME_TEST
-/* The primary purpose of this check is to verify that _DEFAULT_NET_NAMING_SCHEME_TEST
- * is a valid identifier. If an invalid name is given during configuration, this will
- * fail with a name error. */
-assert_cc(_DEFAULT_NET_NAMING_SCHEME_TEST >= 0);
-#endif
-
 static const NamingScheme naming_schemes[] = {
         { "v238", NAMING_V238 },
         { "v239", NAMING_V239 },
@@ -27,6 +20,7 @@ static const NamingScheme naming_schemes[] = {
         { "v252", NAMING_V252 },
         { "v253", NAMING_V253 },
         { "v254", NAMING_V254 },
+        { "v255", NAMING_V255 },
         /* … add more schemes here, as the logic to name devices is updated … */
 
         EXTRA_NET_NAMING_MAP
@@ -87,23 +81,23 @@ const NamingScheme* naming_scheme(void) {
 }
 
 static const char* const name_policy_table[_NAMEPOLICY_MAX] = {
-        [NAMEPOLICY_KERNEL] = "kernel",
-        [NAMEPOLICY_KEEP] = "keep",
+        [NAMEPOLICY_KERNEL]   = "kernel",
+        [NAMEPOLICY_KEEP]     = "keep",
         [NAMEPOLICY_DATABASE] = "database",
-        [NAMEPOLICY_ONBOARD] = "onboard",
-        [NAMEPOLICY_SLOT] = "slot",
-        [NAMEPOLICY_PATH] = "path",
-        [NAMEPOLICY_MAC] = "mac",
+        [NAMEPOLICY_ONBOARD]  = "onboard",
+        [NAMEPOLICY_SLOT]     = "slot",
+        [NAMEPOLICY_PATH]     = "path",
+        [NAMEPOLICY_MAC]      = "mac",
 };
 
 DEFINE_STRING_TABLE_LOOKUP(name_policy, NamePolicy);
 
 static const char* const alternative_names_policy_table[_NAMEPOLICY_MAX] = {
         [NAMEPOLICY_DATABASE] = "database",
-        [NAMEPOLICY_ONBOARD] = "onboard",
-        [NAMEPOLICY_SLOT] = "slot",
-        [NAMEPOLICY_PATH] = "path",
-        [NAMEPOLICY_MAC] = "mac",
+        [NAMEPOLICY_ONBOARD]  = "onboard",
+        [NAMEPOLICY_SLOT]     = "slot",
+        [NAMEPOLICY_PATH]     = "path",
+        [NAMEPOLICY_MAC]      = "mac",
 };
 
 DEFINE_STRING_TABLE_LOOKUP(alternative_names_policy, NamePolicy);

src/shared/netif-naming-scheme.h

@@ -54,7 +54,11 @@ typedef enum NamingSchemeFlags {
         NAMING_V251 = NAMING_V250 | NAMING_BRIDGE_MULTIFUNCTION_SLOT,
         NAMING_V252 = NAMING_V251 | NAMING_DEVICETREE_ALIASES,
         NAMING_V253 = NAMING_V252 | NAMING_USB_HOST,
-        NAMING_V254 = NAMING_V253 | NAMING_SR_IOV_R,
+        NAMING_V254 = NAMING_V253 | NAMING_SR_IOV_R,  /* Despite the name, "v254" is NOT the default scheme
+                                                       * for systemd version 254. It was added in a follow-up
+                                                       * patch later. NAMING_SR_IOV_R is enabled by default in
+                                                       * systemd version 255, naming scheme "v255". */
+        NAMING_V255 = NAMING_V254,
 
         EXTRA_NET_NAMING_SCHEMES
 

src/test/test-net-naming-scheme.c

@@ -4,10 +4,19 @@
 #include "string-util.h"
 #include "tests.h"
 
+#ifdef _DEFAULT_NET_NAMING_SCHEME
+/* The primary purpose of this check is to verify that _DEFAULT_NET_NAMING_SCHEME_TEST
+ * is a valid identifier. If an invalid name is given during configuration, this will
+ * fail with a name error. */
+assert_cc(_DEFAULT_NET_NAMING_SCHEME >= 0);
+#endif
+
 TEST(default_net_naming_scheme) {
         const NamingScheme *n;
         assert_se(n = naming_scheme_from_name(DEFAULT_NET_NAMING_SCHEME));
         log_info("default → %s", n->name);
+
+        assert_se(naming_scheme_from_name(n->name) == n);
 }
 
 TEST(naming_scheme_conversions) {