From b99b055ba975c1663beaf94dbfe8f5c5c7398996 Mon Sep 17 00:00:00 2001

From: Yu Watanabe <watanabe.yu+github@gmail.com>

Date: Sun, 15 Dec 2019 23:21:18 +0900

Subject: [PATCH] udev: support AlternativeName= setting in .link file

(cherry picked from commit a5053a158b43c5ddee90f4915b9fc603e0191d6d)

Related: #1850986

---

 man/systemd.link.xml                     |  8 ++++

 src/libsystemd/sd-netlink/netlink-util.c | 40 ++++++++++++++++

 src/libsystemd/sd-netlink/netlink-util.h |  1 +

 src/shared/conf-parser.c                 | 60 ++++++++++++++++++++++++

 src/shared/conf-parser.h                 |  1 +

 src/udev/net/link-config-gperf.gperf     |  1 +

 src/udev/net/link-config.c               |  5 ++

 src/udev/net/link-config.h               |  1 +

 8 files changed, 117 insertions(+)

diff --git a/man/systemd.link.xml b/man/systemd.link.xml

index 32657308d0..0b0d83349d 100644

--- a/man/systemd.link.xml

+++ b/man/systemd.link.xml

@@ -343,6 +343,14 @@

           </para>

         </listitem>

       </varlistentry>

+      <varlistentry>

+        <term><varname>AlternativeName=</varname></term>

+        <listitem>

+          <para>The alternative interface name to use. This option can be specified multiple times.

+          If the empty string is assigned to this option, the list is reset, and all prior assignments

+          have no effect.</para>

+        </listitem>

+      </varlistentry>

       <varlistentry>

         <term><varname>MTUBytes=</varname></term>

         <listitem>

diff --git a/src/libsystemd/sd-netlink/netlink-util.c b/src/libsystemd/sd-netlink/netlink-util.c

index 3928dfbabf..c1c306f121 100644

--- a/src/libsystemd/sd-netlink/netlink-util.c

+++ b/src/libsystemd/sd-netlink/netlink-util.c

@@ -4,6 +4,7 @@

 #include "netlink-internal.h"

 #include "netlink-util.h"

+#include "strv.h"

 int rtnl_set_link_name(sd_netlink **rtnl, int ifindex, const char *name) {

         _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL;

@@ -80,6 +81,45 @@ int rtnl_set_link_properties(sd_netlink **rtnl, int ifindex, const char *alias,

         return 0;

 }

+int rtnl_set_link_alternative_names(sd_netlink **rtnl, int ifindex, char * const *alternative_names) {

+        _cleanup_(sd_netlink_message_unrefp) sd_netlink_message *message = NULL;

+        int r;

+

+        assert(rtnl);

+        assert(ifindex > 0);

+

+        if (strv_isempty(alternative_names))

+                return 0;

+

+        if (!*rtnl) {

+                r = sd_netlink_open(rtnl);

+                if (r < 0)

+                        return r;

+        }

+

+        r = sd_rtnl_message_new_link(*rtnl, &message, RTM_NEWLINKPROP, ifindex);

+        if (r < 0)

+                return r;

+

+        r = sd_netlink_message_open_container(message, IFLA_PROP_LIST);

+        if (r < 0)

+                return r;

+

+        r = sd_netlink_message_append_strv(message, IFLA_ALT_IFNAME, alternative_names);

+        if (r < 0)

+                return r;

+

+        r = sd_netlink_message_close_container(message);

+        if (r < 0)

+                return r;

+

+        r = sd_netlink_call(*rtnl, message, 0, NULL);

+        if (r < 0)

+                return r;

+

+        return 0;

+}

+

 int rtnl_message_new_synthetic_error(sd_netlink *rtnl, int error, uint32_t serial, sd_netlink_message **ret) {

         struct nlmsgerr *err;

         int r;

diff --git a/src/libsystemd/sd-netlink/netlink-util.h b/src/libsystemd/sd-netlink/netlink-util.h

index 882a616310..92de19c092 100644

--- a/src/libsystemd/sd-netlink/netlink-util.h

+++ b/src/libsystemd/sd-netlink/netlink-util.h

@@ -38,6 +38,7 @@ static inline bool rtnl_message_type_is_routing_policy_rule(uint16_t type) {

 int rtnl_set_link_name(sd_netlink **rtnl, int ifindex, const char *name);

 int rtnl_set_link_properties(sd_netlink **rtnl, int ifindex, const char *alias, const struct ether_addr *mac, uint32_t mtu);

+int rtnl_set_link_alternative_names(sd_netlink **rtnl, int ifindex, char * const *alternative_names);

 int rtnl_log_parse_error(int r);

 int rtnl_log_create_error(int r);

diff --git a/src/shared/conf-parser.c b/src/shared/conf-parser.c

index 246b7431e4..1f40f00c72 100644

--- a/src/shared/conf-parser.c

+++ b/src/shared/conf-parser.c

@@ -970,6 +970,66 @@ int config_parse_ifname(

         return 0;

 }

+int config_parse_ifnames(

+                const char *unit,

+                const char *filename,

+                unsigned line,

+                const char *section,

+                unsigned section_line,

+                const char *lvalue,

+                int ltype,

+                const char *rvalue,

+                void *data,

+                void *userdata) {

+

+        _cleanup_strv_free_ char **names = NULL;

+        char ***s = data;

+        const char *p;

+        int r;

+

+        assert(filename);

+        assert(lvalue);

+        assert(rvalue);

+        assert(data);

+

+        if (isempty(rvalue)) {

+                *s = strv_free(*s);

+                return 0;

+        }

+

+        p = rvalue;

+        for (;;) {

+                _cleanup_free_ char *word = NULL;

+

+                r = extract_first_word(&p, &word, NULL, 0);

+                if (r < 0) {

+                        log_syntax(unit, LOG_ERR, filename, line, r,

+                                   "Failed to extract interface name, ignoring assignment: %s",

+                                   rvalue);

+                        return 0;

+                }

+                if (r == 0)

+                        break;

+

+                if (!ifname_valid_full(word, ltype)) {

+                        log_syntax(unit, LOG_ERR, filename, line, 0,

+                                   "Interface name is not valid or too long, ignoring assignment: %s",

+                                   word);

+                        continue;

+                }

+

+                r = strv_consume(&names, TAKE_PTR(word));

+                if (r < 0)

+                        return log_oom();

+        }

+

+        r = strv_extend_strv(s, names, true);

+        if (r < 0)

+                return log_oom();

+

+        return 0;

+}

+

 int config_parse_ip_port(

                 const char *unit,

                 const char *filename,

diff --git a/src/shared/conf-parser.h b/src/shared/conf-parser.h

index a0a5c89c27..375b2e5a74 100644

--- a/src/shared/conf-parser.h

+++ b/src/shared/conf-parser.h

@@ -137,6 +137,7 @@ CONFIG_PARSER_PROTOTYPE(config_parse_signal);

 CONFIG_PARSER_PROTOTYPE(config_parse_personality);

 CONFIG_PARSER_PROTOTYPE(config_parse_permille);

 CONFIG_PARSER_PROTOTYPE(config_parse_ifname);

+CONFIG_PARSER_PROTOTYPE(config_parse_ifnames);

 CONFIG_PARSER_PROTOTYPE(config_parse_ip_port);

 CONFIG_PARSER_PROTOTYPE(config_parse_join_controllers);

 CONFIG_PARSER_PROTOTYPE(config_parse_mtu);

diff --git a/src/udev/net/link-config-gperf.gperf b/src/udev/net/link-config-gperf.gperf

index b37836d852..913c754145 100644

--- a/src/udev/net/link-config-gperf.gperf

+++ b/src/udev/net/link-config-gperf.gperf

@@ -34,6 +34,7 @@ Link.MACAddressPolicy,           config_parse_mac_policy,    0,

 Link.MACAddress,                 config_parse_hwaddr,        0,                             offsetof(link_config, mac)

 Link.NamePolicy,                 config_parse_name_policy,   0,                             offsetof(link_config, name_policy)

 Link.Name,                       config_parse_ifname,        0,                             offsetof(link_config, name)

+Link.AlternativeName,            config_parse_ifnames,       1,                             offsetof(link_config, alternative_names)

 Link.Alias,                      config_parse_ifalias,       0,                             offsetof(link_config, alias)

 Link.MTUBytes,                   config_parse_mtu,           AF_UNSPEC,                     offsetof(link_config, mtu)

 Link.BitsPerSecond,              config_parse_si_size,       0,                             offsetof(link_config, speed)

diff --git a/src/udev/net/link-config.c b/src/udev/net/link-config.c

index 5113586457..d07a1a1874 100644

--- a/src/udev/net/link-config.c

+++ b/src/udev/net/link-config.c

@@ -67,6 +67,7 @@ static void link_config_free(link_config *link) {

         free(link->mac);

         free(link->name_policy);

         free(link->name);

+        strv_free(link->alternative_names);

         free(link->alias);

         free(link);

@@ -468,6 +469,10 @@ int link_config_apply(link_config_ctx *ctx, link_config *config,

         if (r < 0)

                 return log_warning_errno(r, "Could not set Alias=, MACAddress= or MTU= on %s: %m", old_name);

+        r = rtnl_set_link_alternative_names(&ctx->rtnl, ifindex, config->alternative_names);

+        if (r < 0)

+                return log_warning_errno(r, "Could not set AlternativeName= on %s: %m", old_name);

+

         *name = new_name;

         return 0;

diff --git a/src/udev/net/link-config.h b/src/udev/net/link-config.h

index 4798bb101c..93d5fdce59 100644

--- a/src/udev/net/link-config.h

+++ b/src/udev/net/link-config.h

@@ -50,6 +50,7 @@ struct link_config {

         MACPolicy mac_policy;

         NamePolicy *name_policy;

         char *name;

+        char **alternative_names;

         char *alias;

         uint32_t mtu;

         size_t speed;