[PATCH net-next RFC v1 06/27] afnetns: put afnetns pointer into struct sock

[Hannes Frederic Sowa]

All sockets are associated to its creator's afnet namespace.

A little bit care must be taken about in-kernel socket creation.
Basically we associate kernel pointers to the current's net namespace
afnet and don't use the process contexts afnetns.

Signed-off-by: Hannes Frederic Sowa <han...@stressinduktion.org>
---
 include/net/sock.h |  4 ++++
 net/core/sock.c    | 18 ++++++++++++++++--
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index 6db7693b9e6185..1e05d497db2520 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -183,6 +183,9 @@ struct sock_common {
        };
        struct proto            *skc_prot;
        possible_net_t          skc_net;
+#if IS_ENABLED(CONFIG_AFNETNS)
+       struct afnetns          *skc_afnet;
+#endif
 
 #if IS_ENABLED(CONFIG_IPV6)
        struct in6_addr         skc_v6_daddr;
@@ -337,6 +340,7 @@ struct sock {
 #define sk_bind_node           __sk_common.skc_bind_node
 #define sk_prot                        __sk_common.skc_prot
 #define sk_net                 __sk_common.skc_net
+#define sk_afnet               __sk_common.skc_afnet
 #define sk_v6_daddr            __sk_common.skc_v6_daddr
 #define sk_v6_rcv_saddr        __sk_common.skc_v6_rcv_saddr
 #define sk_cookie              __sk_common.skc_cookie
diff --git a/net/core/sock.c b/net/core/sock.c
index 768aedf238f5b4..542d496858f993 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1458,6 +1458,12 @@ struct sock *sk_alloc(struct net *net, int family, gfp_t 
priority,
                if (likely(sk->sk_net_refcnt))
                        get_net(net);
                sock_net_set(sk, net);
+#if IS_ENABLED(CONFIG_AFNETNS)
+               if (likely(sk->sk_net_refcnt))
+                       sk->sk_afnet = afnetns_get(current->nsproxy->afnet_ns);
+               else
+                       sk->sk_afnet = net->afnet_ns;
+#endif
                atomic_set(&sk->sk_wmem_alloc, 1);
 
                mem_cgroup_sk_alloc(sk);
@@ -1499,8 +1505,12 @@ static void __sk_destruct(struct rcu_head *head)
        if (sk->sk_peer_cred)
                put_cred(sk->sk_peer_cred);
        put_pid(sk->sk_peer_pid);
-       if (likely(sk->sk_net_refcnt))
+       if (likely(sk->sk_net_refcnt)) {
                put_net(sock_net(sk));
+#if IS_ENABLED(CONFIG_AFNETNS)
+               afnetns_put(sk->sk_afnet);
+#endif
+       }
        sk_prot_free(sk->sk_prot_creator, sk);
 }
 
@@ -1572,8 +1582,12 @@ struct sock *sk_clone_lock(const struct sock *sk, const 
gfp_t priority)
                sock_copy(newsk, sk);
 
                /* SANITY */
-               if (likely(newsk->sk_net_refcnt))
+               if (likely(newsk->sk_net_refcnt)) {
                        get_net(sock_net(newsk));
+#if IS_ENABLED(CONFIG_AFNETNS)
+                       afnetns_get(newsk->sk_afnet);
+#endif
+               }
                sk_node_init(&newsk->sk_node);
                sock_lock_init(newsk);
                bh_lock_sock(newsk);
-- 
2.9.3