From 843f4a55e336e6d0c7bb92e7f9621535bc8d5fcd Mon Sep 17 00:00:00 2001 From: Yuchung Cheng Date: Sun, 11 May 2014 20:22:11 -0700 Subject: tcp: use tcp_v4_send_synack on first SYN-ACK To avoid large code duplication in IPv6, we need to first simplify the complicate SYN-ACK sending code in tcp_v4_conn_request(). To use tcp_v4(6)_send_synack() to send all SYN-ACKs, we need to initialize the mini socket's receive window before trying to create the child socket and/or building the SYN-ACK packet. So we move that initialization from tcp_make_synack() to tcp_v4_conn_request() as a new function tcp_openreq_init_req_rwin(). After this refactoring the SYN-ACK sending code is simpler and easier to implement Fast Open for IPv6. Signed-off-by: Yuchung Cheng Signed-off-by: Daniel Lee Signed-off-by: Jerry Chu Acked-by: Neal Cardwell Signed-off-by: David S. Miller --- net/ipv4/tcp_minisocks.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'net/ipv4/tcp_minisocks.c') diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index 05c1b155251d..e68e0d4af6c9 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -362,6 +362,37 @@ void tcp_twsk_destructor(struct sock *sk) } EXPORT_SYMBOL_GPL(tcp_twsk_destructor); +void tcp_openreq_init_rwin(struct request_sock *req, + struct sock *sk, struct dst_entry *dst) +{ + struct inet_request_sock *ireq = inet_rsk(req); + struct tcp_sock *tp = tcp_sk(sk); + __u8 rcv_wscale; + int mss = dst_metric_advmss(dst); + + if (tp->rx_opt.user_mss && tp->rx_opt.user_mss < mss) + mss = tp->rx_opt.user_mss; + + /* Set this up on the first call only */ + req->window_clamp = tp->window_clamp ? : dst_metric(dst, RTAX_WINDOW); + + /* limit the window selection if the user enforce a smaller rx buffer */ + if (sk->sk_userlocks & SOCK_RCVBUF_LOCK && + (req->window_clamp > tcp_full_space(sk) || req->window_clamp == 0)) + req->window_clamp = tcp_full_space(sk); + + /* tcp_full_space because it is guaranteed to be the first packet */ + tcp_select_initial_window(tcp_full_space(sk), + mss - (ireq->tstamp_ok ? TCPOLEN_TSTAMP_ALIGNED : 0), + &req->rcv_wnd, + &req->window_clamp, + ireq->wscale_ok, + &rcv_wscale, + dst_metric(dst, RTAX_INITRWND)); + ireq->rcv_wscale = rcv_wscale; +} +EXPORT_SYMBOL(tcp_openreq_init_rwin); + static inline void TCP_ECN_openreq_child(struct tcp_sock *tp, struct request_sock *req) { -- cgit v1.2.3