geneve: Add dualstack flag to struct geneve_config.

When collect metadata mode (IFLA_GENEVE_COLLECT_METADATA) is
enabled, the GENEVE device creates both IPv4 and IPv6 sockets
and bind()s them to wildcard addresses.

The next patch allows creating only one socket bound to a
specific address even when the collect metadata mode is
enabled.

Then, we need a flag to distinguish dualstack GENEVE devices
to detect local address conflict.

Let's add the dualstack flag to struct geneve_config.

IFLA_GENEVE_COLLECT_METADATA processing is moved up in
geneve_nl2info() for the next patch to overwrite dualstack
to false while keeping collect_md true.

Note that IFLA_GENEVE_REMOTE and IFLA_GENEVE_REMOTE6 does not
set cfg->dualstack to false since is_tnl_info_zero() ignores
the wildcard remote address:

  # ip link add geneve0 type geneve external remote 0.0.0.1
  Error: Device is externally controlled, so attributes (VNI, Port, and so on) must not be specified.

  # ip link add geneve0 type geneve external remote 0.0.0.0
  # ss -ua | grep geneve
  UNCONN 0      0            0.0.0.0:geneve      0.0.0.0:*
  UNCONN 0      0                  *:geneve            *:*

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260602190436.139591-5-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index 4f841eced028d7f0a4393cf83add6dca07c75c59..3a62d132a8c4a4d9d22417d4e812eb8c49e355cb 100644 (file)
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -73,6 +73,7 @@ struct geneve_dev_node {
 
 struct geneve_config {
        bool                    collect_md;
+       bool                    dualstack;
        bool                    use_udp6_rx_checksums;
        bool                    ttl_inherit;
        bool                    gro_hint;
@@ -1108,12 +1109,12 @@ out:
 static int geneve_open(struct net_device *dev)
 {
        struct geneve_dev *geneve = netdev_priv(dev);
-       bool metadata = geneve->cfg.collect_md;
+       bool dualstack = geneve->cfg.dualstack;
        bool ipv4, ipv6;
        int ret = 0;
 
-       ipv6 = geneve->cfg.info.mode & IP_TUNNEL_INFO_IPV6 || metadata;
-       ipv4 = !ipv6 || metadata;
+       ipv6 = geneve->cfg.info.mode & IP_TUNNEL_INFO_IPV6 || dualstack;
+       ipv4 = !ipv6 || dualstack;
 #if IS_ENABLED(CONFIG_IPV6)
        if (ipv6) {
                ret = geneve_sock_add(geneve, true);
@@ -1906,6 +1907,16 @@ static int geneve_nl2info(struct nlattr *tb[], struct nlattr *data[],
        struct ip_tunnel_info *info = &cfg->info;
        int attrtype;
 
+       if (data[IFLA_GENEVE_COLLECT_METADATA]) {
+               if (changelink) {
+                       attrtype = IFLA_GENEVE_COLLECT_METADATA;
+                       goto change_notsup;
+               }
+
+               cfg->collect_md = true;
+               cfg->dualstack = true;
+       }
+
        if (data[IFLA_GENEVE_REMOTE] && data[IFLA_GENEVE_REMOTE6]) {
                NL_SET_ERR_MSG(extack,
                               "Cannot specify both IPv4 and IPv6 Remote addresses");
@@ -2025,14 +2036,6 @@ static int geneve_nl2info(struct nlattr *tb[], struct nlattr *data[],
                cfg->port_max = ntohs(p->high);
        }
 
-       if (data[IFLA_GENEVE_COLLECT_METADATA]) {
-               if (changelink) {
-                       attrtype = IFLA_GENEVE_COLLECT_METADATA;
-                       goto change_notsup;
-               }
-               cfg->collect_md = true;
-       }
-
        if (data[IFLA_GENEVE_UDP_CSUM]) {
                if (changelink) {
                        attrtype = IFLA_GENEVE_UDP_CSUM;
@@ -2153,6 +2156,7 @@ static int geneve_newlink(struct net_device *dev,
                .use_udp6_rx_checksums = false,
                .ttl_inherit = false,
                .collect_md = false,
+               .dualstack = false,
                .port_min = 1,
                .port_max = USHRT_MAX,
        };
@@ -2382,6 +2386,7 @@ struct net_device *geneve_dev_create_fb(struct net *net, const char *name,
                .use_udp6_rx_checksums = true,
                .ttl_inherit = false,
                .collect_md = true,
+               .dualstack = true,
                .port_min = 1,
                .port_max = USHRT_MAX,
        };