From 8336886f786fdacbc19b719c1f7ea91eb70706d4 Mon Sep 17 00:00:00 2001 From: Jerry Chu Date: Fri, 31 Aug 2012 12:29:12 +0000 Subject: tcp: TCP Fast Open Server - support TFO listeners This patch builds on top of the previous patch to add the support for TFO listeners. This includes - 1. allocating, properly initializing, and managing the per listener fastopen_queue structure when TFO is enabled 2. changes to the inet_csk_accept code to support TFO. E.g., the request_sock can no longer be freed upon accept(), not until 3WHS finishes 3. allowing a TCP_SYN_RECV socket to properly poll() and sendmsg() if it's a TFO socket 4. properly closing a TFO listener, and a TFO socket before 3WHS finishes 5. supporting TCP_FASTOPEN socket option 6. modifying tcp_check_req() to use to check a TFO socket as well as request_sock 7. supporting TCP's TFO cookie option 8. adding a new SYN-ACK retransmit handler to use the timer directly off the TFO socket rather than the listener socket. Note that TFO server side will not retransmit anything other than SYN-ACK until the 3WHS is completed. The patch also contains an important function "reqsk_fastopen_remove()" to manage the somewhat complex relation between a listener, its request_sock, and the corresponding child socket. See the comment above the function for the detail. Signed-off-by: H.K. Jerry Chu Cc: Yuchung Cheng Cc: Neal Cardwell Cc: Eric Dumazet Cc: Tom Herbert Signed-off-by: David S. Miller --- net/ipv4/af_inet.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-) (limited to 'net/ipv4/af_inet.c') diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index 6681ccf5c3ee..4f70ef0b946d 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -149,6 +149,11 @@ void inet_sock_destruct(struct sock *sk) pr_err("Attempt to release alive inet socket %p\n", sk); return; } + if (sk->sk_type == SOCK_STREAM) { + struct fastopen_queue *fastopenq = + inet_csk(sk)->icsk_accept_queue.fastopenq; + kfree(fastopenq); + } WARN_ON(atomic_read(&sk->sk_rmem_alloc)); WARN_ON(atomic_read(&sk->sk_wmem_alloc)); @@ -212,6 +217,26 @@ int inet_listen(struct socket *sock, int backlog) * we can only allow the backlog to be adjusted. */ if (old_state != TCP_LISTEN) { + /* Check special setups for testing purpose to enable TFO w/o + * requiring TCP_FASTOPEN sockopt. + * Note that only TCP sockets (SOCK_STREAM) will reach here. + * Also fastopenq may already been allocated because this + * socket was in TCP_LISTEN state previously but was + * shutdown() (rather than close()). + */ + if ((sysctl_tcp_fastopen & TFO_SERVER_ENABLE) != 0 && + inet_csk(sk)->icsk_accept_queue.fastopenq == NULL) { + if ((sysctl_tcp_fastopen & TFO_SERVER_WO_SOCKOPT1) != 0) + err = fastopen_init_queue(sk, backlog); + else if ((sysctl_tcp_fastopen & + TFO_SERVER_WO_SOCKOPT2) != 0) + err = fastopen_init_queue(sk, + ((uint)sysctl_tcp_fastopen) >> 16); + else + err = 0; + if (err) + goto out; + } err = inet_csk_listen_start(sk, backlog); if (err) goto out; @@ -701,7 +726,8 @@ int inet_accept(struct socket *sock, struct socket *newsock, int flags) sock_rps_record_flow(sk2); WARN_ON(!((1 << sk2->sk_state) & - (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_CLOSE))); + (TCPF_ESTABLISHED | TCPF_SYN_RECV | + TCPF_CLOSE_WAIT | TCPF_CLOSE))); sock_graft(sk2, newsock); -- cgit v1.2.3-59-g8ed1b