tcp: fix validation of D-SACK

D-SACK is allowed to reside below snd_una. But the corresponding check
in tcp_is_sackblock_valid() is the exact opposite. It looks like a typo.

Signed-off-by: Zheng Yan <zheng.z.yan@intel.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index ea0d218..21fab3e 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1124,7 +1124,7 @@ static int tcp_is_sackblock_valid(struct tcp_sock *tp, int is_dsack,
                return 0;
 
        /* ...Then it's D-SACK, and must reside below snd_una completely */
-       if (!after(end_seq, tp->snd_una))
+       if (after(end_seq, tp->snd_una))
                return 0;
 
        if (!before(start_seq, tp->undo_marker))