diff options
| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-05-17 22:35:36 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-08-02 10:29:19 -0700 |
| commit | a1899b1af296841f26afc39194d1857f963cbbac (patch) | |
| tree | b1b456f7555580f979d1226573e11410a9d9225c /net | |
| parent | efa4be3c2cb92b1d9d7d04ab91736cfc937a9764 (diff) | |
tcp: tcp_synack_options() fix
[ Upstream commit de213e5eedecdfb1b1eea7e6be28bc64cac5c078 ]
Commit 33ad798c924b4a (tcp: options clean up) introduced a problem
if MD5+SACK+timestamps were used in initial SYN message.
Some stacks (old linux for example) try to negotiate MD5+SACK+TSTAMP
sessions, but since 40 bytes of tcp options space are not enough to
store all the bits needed, we chose to disable timestamps in this case.
We send a SYN-ACK _without_ timestamp option, but socket has timestamps
enabled and all further outgoing messages contain a TS block, all with
the initial timestamp of the remote peer.
Fix is to really disable timestamps option for the whole session.
Reported-by: Bijay Singh <Bijay.Singh@guavus.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp_output.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 0dda86e72ad8..3ef4adee64a3 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -667,7 +667,6 @@ static unsigned tcp_synack_options(struct sock *sk, u8 cookie_plus = (xvp != NULL && !xvp->cookie_out_never) ? xvp->cookie_plus : 0; - bool doing_ts = ireq->tstamp_ok; #ifdef CONFIG_TCP_MD5SIG *md5 = tcp_rsk(req)->af_specific->md5_lookup(sk, req); @@ -680,7 +679,7 @@ static unsigned tcp_synack_options(struct sock *sk, * rather than TS in order to fit in better with old, * buggy kernels, but that was deemed to be unnecessary. */ - doing_ts &= !ireq->sack_ok; + ireq->tstamp_ok &= !ireq->sack_ok; } #else *md5 = NULL; @@ -695,7 +694,7 @@ static unsigned tcp_synack_options(struct sock *sk, opts->options |= OPTION_WSCALE; remaining -= TCPOLEN_WSCALE_ALIGNED; } - if (likely(doing_ts)) { + if (likely(ireq->tstamp_ok)) { opts->options |= OPTION_TS; opts->tsval = TCP_SKB_CB(skb)->when; opts->tsecr = req->ts_recent; @@ -703,7 +702,7 @@ static unsigned tcp_synack_options(struct sock *sk, } if (likely(ireq->sack_ok)) { opts->options |= OPTION_SACK_ADVERTISE; - if (unlikely(!doing_ts)) + if (unlikely(!ireq->tstamp_ok)) remaining -= TCPOLEN_SACKPERM_ALIGNED; } @@ -711,7 +710,7 @@ static unsigned tcp_synack_options(struct sock *sk, * If the <SYN> options fit, the same options should fit now! */ if (*md5 == NULL && - doing_ts && + ireq->tstamp_ok && cookie_plus > TCPOLEN_COOKIE_BASE) { int need = cookie_plus; /* has TCPOLEN_COOKIE_BASE */ |