sit: advertise tunnel param via rtnl

It is usefull for daemons that monitor link event to have the full parameters of
these interfaces when a rtnl message is sent.
It allows also to dump them via rtnetlink.

It is based on what is done for GRE tunnels.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 56 insertions, 1 deletions

diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c
index 3ed54ffd8d50..b543c56cad28 100644
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -68,6 +68,7 @@
 static int ipip6_tunnel_init(struct net_device *dev);
 static void ipip6_tunnel_setup(struct net_device *dev);
 static void ipip6_dev_free(struct net_device *dev);
+static struct rtnl_link_ops sit_link_ops __read_mostly;
 
 static int sit_net_id __read_mostly;
 struct sit_net {
@@ -282,6 +283,7 @@ static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
                 goto failed_free;
 
         strcpy(nt->parms.name, dev->name);
+        dev->rtnl_link_ops = &sit_link_ops;
 
         dev_hold(dev);
 
@@ -1216,6 +1218,47 @@ static int __net_init ipip6_fb_tunnel_init(struct net_device *dev)
         return 0;
 }
 
+static size_t sit_get_size(const struct net_device *dev)
+{
+        return
+                /* IFLA_IPTUN_LINK */
+                nla_total_size(4) +
+                /* IFLA_IPTUN_LOCAL */
+                nla_total_size(4) +
+                /* IFLA_IPTUN_REMOTE */
+                nla_total_size(4) +
+                /* IFLA_IPTUN_TTL */
+                nla_total_size(1) +
+                /* IFLA_IPTUN_TOS */
+                nla_total_size(1) +
+                0;
+}
+
+static int sit_fill_info(struct sk_buff *skb, const struct net_device *dev)
+{
+        struct ip_tunnel *tunnel = netdev_priv(dev);
+        struct ip_tunnel_parm *parm = &tunnel->parms;
+
+        if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
+            nla_put_be32(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
+            nla_put_be32(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
+            nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
+            nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos))
+                goto nla_put_failure;
+        return 0;
+
+nla_put_failure:
+        return -EMSGSIZE;
+}
+
+static struct rtnl_link_ops sit_link_ops __read_mostly = {
+        .kind           = "sit",
+        .maxtype        = IFLA_IPTUN_MAX,
+        .priv_size      = sizeof(struct ip_tunnel),
+        .get_size       = sit_get_size,
+        .fill_info      = sit_fill_info,
+};
+
 static struct xfrm_tunnel sit_handler __read_mostly = {
         .handler        =       ipip6_rcv,
         .err_handler    =       ipip6_err,
@@ -1302,6 +1345,7 @@ static struct pernet_operations sit_net_ops = {
 
 static void __exit sit_cleanup(void)
 {
+        rtnl_link_unregister(&sit_link_ops);
         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
 
         unregister_pernet_device(&sit_net_ops);
@@ -1319,10 +1363,21 @@ static int __init sit_init(void)
                 return err;
         err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
         if (err < 0) {
-                unregister_pernet_device(&sit_net_ops);
                 pr_info("%s: can't add protocol\n", __func__);
+                goto xfrm_tunnel_failed;
         }
+        err = rtnl_link_register(&sit_link_ops);
+        if (err < 0)
+                goto rtnl_link_failed;
+
+out:
         return err;
+
+rtnl_link_failed:
+        xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
+xfrm_tunnel_failed:
+        unregister_pernet_device(&sit_net_ops);
+        goto out;
 }
 
 module_init(sit_init);