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| author | Wei Yongjun <yjwei@cn.fujitsu.com> | 2009-06-24 22:29:31 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-06-25 20:03:15 -0700 |
| commit | 1ac530b3553e0b4dc1e18a32bed57cfa84cd57cb (patch) | |
| tree | cc0198945aeee7b60ea06c1699fc72268efc26f7 /net/ipv4/tcp_minisocks.c | |
| parent | d8146bb23ea045fb75c56b4e3b53f0964eed4076 (diff) | |
| download | lwn-1ac530b3553e0b4dc1e18a32bed57cfa84cd57cb.tar.gz lwn-1ac530b3553e0b4dc1e18a32bed57cfa84cd57cb.zip | |
tcp: missing check ACK flag of received segment in FIN-WAIT-2 state
RFC0793 defined that in FIN-WAIT-2 state if the ACK bit is off drop
the segment and return[Page 72]. But this check is missing in function
tcp_timewait_state_process(). This cause the segment with FIN flag but
no ACK has two diffent action:
Case 1:
Node A Node B
<------------- FIN,ACK
(enter FIN-WAIT-1)
ACK ------------->
(enter FIN-WAIT-2)
FIN -------------> discard
(move sk to tw list)
Case 2:
Node A Node B
<------------- FIN,ACK
(enter FIN-WAIT-1)
ACK ------------->
(enter FIN-WAIT-2)
(move sk to tw list)
FIN ------------->
<------------- ACK
This patch fixed the problem.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_minisocks.c')
| -rw-r--r-- | net/ipv4/tcp_minisocks.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index 43bbba7926ee..f8d67ccc64f3 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -128,7 +128,8 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, goto kill_with_rst; /* Dup ACK? */ - if (!after(TCP_SKB_CB(skb)->end_seq, tcptw->tw_rcv_nxt) || + if (!th->ack || + !after(TCP_SKB_CB(skb)->end_seq, tcptw->tw_rcv_nxt) || TCP_SKB_CB(skb)->end_seq == TCP_SKB_CB(skb)->seq) { inet_twsk_put(tw); return TCP_TW_SUCCESS; |