diff options
| author |   Yuchung Cheng <ycheng@google.com> | 2012-07-19 06:43:11 +0000 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2012-07-19 11:02:03 -0700 |
| commit | 67da22d23fa6f3324e03bcd0580b914b2e4afbf3 (patch) | |
| tree | e794826d1dd7e30cf0885cbe93f22bc050c62359 /net/ipv4/tcp_input.c | |
| parent | net-tcp: Fast Open client - detecting SYN-data drops (diff) | |
| download | linux-dev-67da22d23fa6f3324e03bcd0580b914b2e4afbf3.tar.xz linux-dev-67da22d23fa6f3324e03bcd0580b914b2e4afbf3.zip | |
net-tcp: Fast Open client - cookie-less mode
In trusted networks, e.g., intranet, data-center, the client does not
need to use Fast Open cookie to mitigate DoS attacks. In cookie-less
mode, sendmsg() with MSG_FASTOPEN flag will send SYN-data regardless
of cookie availability.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_input.c')
| -rw-r--r-- | net/ipv4/tcp_input.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index c49a4fc175bd..e67d685a6c0e 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5650,7 +5650,7 @@ static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack, struct tcp_fastopen_cookie *cookie) { struct tcp_sock *tp = tcp_sk(sk); - struct sk_buff *data = tcp_write_queue_head(sk); + struct sk_buff *data = tp->syn_data ? tcp_write_queue_head(sk) : NULL; u16 mss = tp->rx_opt.mss_clamp; bool syn_drop; @@ -5665,6 +5665,9 @@ static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack, mss = opt.mss_clamp; } + if (!tp->syn_fastopen) /* Ignore an unsolicited cookie */ + cookie->len = -1; + /* The SYN-ACK neither has cookie nor acknowledges the data. Presumably * the remote receives only the retransmitted (regular) SYNs: either * the original SYN-data or the corresponding SYN-ACK is lost. @@ -5816,7 +5819,8 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb, tcp_finish_connect(sk, skb); - if (tp->syn_fastopen && tcp_rcv_fastopen_synack(sk, skb, &foc)) + if ((tp->syn_fastopen || tp->syn_data) && + tcp_rcv_fastopen_synack(sk, skb, &foc)) return -1; if (sk->sk_write_pending || |