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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-05-17 22:35:36 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-05-17 22:35:36 -0700 |
| commit | de213e5eedecdfb1b1eea7e6be28bc64cac5c078 (patch) | |
| tree | dee5fa7e4874332b65c95dc2e9ee463a5652c519 /net | |
| parent | eedf042a63ffef050ebc015de19b52dc065e830b (diff) | |
| download | linux-de213e5eedecdfb1b1eea7e6be28bc64cac5c078.tar.gz linux-de213e5eedecdfb1b1eea7e6be28bc64cac5c078.tar.bz2 linux-de213e5eedecdfb1b1eea7e6be28bc64cac5c078.zip | |
tcp: tcp_synack_options() fix
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>
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 18a3302480cb..b4ed957f201a 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -668,7 +668,6 @@ 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); @@ -681,7 +680,7 @@ 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; @@ -696,7 +695,7 @@ 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; @@ -704,7 +703,7 @@ 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; } @@ -712,7 +711,7 @@ 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 */ |