[PATCH 3.10 03/16] tcp: fix tcp_release_cb() to dispatch via address family for mtu_reduced()

From: Greg Kroah-Hartman
Date: Sun Oct 12 2014 - 22:25:39 EST


3.10-stable review patch. If anyone has any objections, please let me know.

------------------

From: Neal Cardwell <ncardwell@xxxxxxxxxx>

[ Upstream commit 4fab9071950c2021d846e18351e0f46a1cffd67b ]

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@xxxxxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Diagnosed-by: Willem de Bruijn <willemb@xxxxxxxxxx>
Fixes: 563d34d057862 ("tcp: dont drop MTU reduction indications")
Reviewed-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/net/inet_connection_sock.h | 1 +
include/net/sock.h | 1 -
include/net/tcp.h | 1 +
net/ipv4/tcp_ipv4.c | 5 +++--
net/ipv4/tcp_output.c | 2 +-
net/ipv6/tcp_ipv6.c | 3 ++-
6 files changed, 8 insertions(+), 5 deletions(-)

--- 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
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -932,7 +932,6 @@ 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);
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -460,6 +460,7 @@ extern const u8 *tcp_parse_md5sig_option
*/

extern void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb);
+void tcp_v4_mtu_reduced(struct sock *sk);
extern int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb);
extern struct sock * tcp_create_openreq_child(struct sock *sk,
struct request_sock *req,
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -268,7 +268,7 @@ 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);
@@ -298,6 +298,7 @@ static void tcp_v4_mtu_reduced(struct so
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)
{
@@ -2142,6 +2143,7 @@ const struct inet_connection_sock_af_ops
.compat_setsockopt = compat_ip_setsockopt,
.compat_getsockopt = compat_ip_getsockopt,
#endif
+ .mtu_reduced = tcp_v4_mtu_reduced,
};
EXPORT_SYMBOL(ipv4_specific);

@@ -2867,7 +2869,6 @@ 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,
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -775,7 +775,7 @@ 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);
}
}
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -1651,6 +1651,7 @@ static const struct inet_connection_sock
.compat_setsockopt = compat_ipv6_setsockopt,
.compat_getsockopt = compat_ipv6_getsockopt,
#endif
+ .mtu_reduced = tcp_v6_mtu_reduced,
};

#ifdef CONFIG_TCP_MD5SIG
@@ -1682,6 +1683,7 @@ static const struct inet_connection_sock
.compat_setsockopt = compat_ipv6_setsockopt,
.compat_getsockopt = compat_ipv6_getsockopt,
#endif
+ .mtu_reduced = tcp_v4_mtu_reduced,
};

#ifdef CONFIG_TCP_MD5SIG
@@ -1919,7 +1921,6 @@ 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,


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