tcp: fix tcp_release_cb() to dispatch via address family for mtu_reduced()

Make sure we use the correct address-family-specific function for
handling MTU reductions from within tcp_release_cb().

Previously AF_INET6 sockets were incorrectly always using the IPv6
code path when sometimes they were handling IPv4 traffic and thus had
an IPv4 dst.

Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Diagnosed-by: Willem de Bruijn <willemb@google.com>
Fixes: 563d34d057862 ("tcp: dont drop MTU reduction indications")
Reviewed-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index 7a43138..5fbe656 100644 (file)
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -62,6 +62,7 @@ struct inet_connection_sock_af_ops {
        void        (*addr2sockaddr)(struct sock *sk, struct sockaddr *);
        int         (*bind_conflict)(const struct sock *sk,
                                     const struct inet_bind_bucket *tb, bool relax);
+       void        (*mtu_reduced)(struct sock *sk);
 };
 
 /** inet_connection_sock - INET connection oriented sock

diff --git a/include/net/sock.h b/include/net/sock.h
index 38805fa..7f2ab72 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -987,7 +987,6 @@ struct proto {
                                                struct sk_buff *skb);
 
        void            (*release_cb)(struct sock *sk);
-       void            (*mtu_reduced)(struct sock *sk);
 
        /* Keeping track of sk's, looking them up, and port selection methods. */
        void                    (*hash)(struct sock *sk);

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 36f5525..e337e05 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -448,6 +448,7 @@ const u8 *tcp_parse_md5sig_option(const struct tcphdr *th);
  */
 
 void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb);
+void tcp_v4_mtu_reduced(struct sock *sk);
 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
 struct sock *tcp_create_openreq_child(struct sock *sk,
                                      struct request_sock *req,

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index dceff5f..cd17f00 100644 (file)
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -271,7 +271,7 @@ EXPORT_SYMBOL(tcp_v4_connect);
  * It can be called through tcp_release_cb() if socket was owned by user
  * at the time tcp_v4_err() was called to handle ICMP message.
  */
-static void tcp_v4_mtu_reduced(struct sock *sk)
+void tcp_v4_mtu_reduced(struct sock *sk)
 {
        struct dst_entry *dst;
        struct inet_sock *inet = inet_sk(sk);
@@ -302,6 +302,7 @@ static void tcp_v4_mtu_reduced(struct sock *sk)
                tcp_simple_retransmit(sk);
        } /* else let the usual retransmit timer handle it */
 }
+EXPORT_SYMBOL(tcp_v4_mtu_reduced);
 
 static void do_redirect(struct sk_buff *skb, struct sock *sk)
 {
@@ -1787,6 +1788,7 @@ const struct inet_connection_sock_af_ops ipv4_specific = {
        .compat_setsockopt = compat_ip_setsockopt,
        .compat_getsockopt = compat_ip_getsockopt,
 #endif
+       .mtu_reduced       = tcp_v4_mtu_reduced,
 };
 EXPORT_SYMBOL(ipv4_specific);
 
@@ -2406,7 +2408,6 @@ struct proto tcp_prot = {
        .sendpage               = tcp_sendpage,
        .backlog_rcv            = tcp_v4_do_rcv,
        .release_cb             = tcp_release_cb,
-       .mtu_reduced            = tcp_v4_mtu_reduced,
        .hash                   = inet_hash,
        .unhash                 = inet_unhash,
        .get_port               = inet_csk_get_port,

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index ff3f0f7..5a7c41f 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -800,7 +800,7 @@ void tcp_release_cb(struct sock *sk)
                __sock_put(sk);
        }
        if (flags & (1UL << TCP_MTU_REDUCED_DEFERRED)) {
-               sk->sk_prot->mtu_reduced(sk);
+               inet_csk(sk)->icsk_af_ops->mtu_reduced(sk);
                __sock_put(sk);
        }
 }

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index f2ce955..29964c3 100644 (file)
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1595,6 +1595,7 @@ static const struct inet_connection_sock_af_ops ipv6_specific = {
        .compat_setsockopt = compat_ipv6_setsockopt,
        .compat_getsockopt = compat_ipv6_getsockopt,
 #endif
+       .mtu_reduced       = tcp_v6_mtu_reduced,
 };
 
 #ifdef CONFIG_TCP_MD5SIG
@@ -1625,6 +1626,7 @@ static const struct inet_connection_sock_af_ops ipv6_mapped = {
        .compat_setsockopt = compat_ipv6_setsockopt,
        .compat_getsockopt = compat_ipv6_getsockopt,
 #endif
+       .mtu_reduced       = tcp_v4_mtu_reduced,
 };
 
 #ifdef CONFIG_TCP_MD5SIG
@@ -1864,7 +1866,6 @@ struct proto tcpv6_prot = {
        .sendpage               = tcp_sendpage,
        .backlog_rcv            = tcp_v6_do_rcv,
        .release_cb             = tcp_release_cb,
-       .mtu_reduced            = tcp_v6_mtu_reduced,
        .hash                   = tcp_v6_hash,
        .unhash                 = inet_unhash,
        .get_port               = inet_csk_get_port,