tcp: fix incorrect LOCKDROPPEDICMPS counter

commit 563d34d057 (tcp: dont drop MTU reduction indications)
added an error leading to incorrect accounting of
LINUX_MIB_LOCKDROPPEDICMPS

If socket is owned by the user, we want to increment
this SNMP counter, unless the message is a
(ICMP_DEST_UNREACH,ICMP_FRAG_NEEDED) one.

Reported-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 5 deletions

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 54139fa514e6..70b09ef2463b 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -369,11 +369,10 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
          * We do take care of PMTU discovery (RFC1191) special case :
          * we can receive locally generated ICMP messages while socket is held.
          */
-        if (sock_owned_by_user(sk) &&
-            type != ICMP_DEST_UNREACH &&
-            code != ICMP_FRAG_NEEDED)
-                NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
-
+        if (sock_owned_by_user(sk)) {
+                if (!(type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED))
+                        NET_INC_STATS_BH(net, LINUX_MIB_LOCKDROPPEDICMPS);
+        }
         if (sk->sk_state == TCP_CLOSE)
                 goto out;