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[TCP]: TCP_DEFER_ACCEPT updates - process as established

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Change TCP_DEFER_ACCEPT implementation so that it transitions a
connection to ESTABLISHED after handshake is complete instead of
leaving it in SYN-RECV until some data arrvies. Place connection in
accept queue when first data packet arrives from slow path.

Benefits:
  - established connection is now reset if it never makes it
   to the accept queue

 - diagnostic state of established matches with the packet traces
   showing completed handshake

 - TCP_DEFER_ACCEPT timeouts are expressed in seconds and can now be
   enforced with reasonable accuracy instead of rounding up to next
   exponential back-off of syn-ack retry.

Signed-off-by: Patrick McManus <mcmanus@ducksong.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Patrick McManus
2008-03-21 16:33:01 -07:00
committed by David S. Miller
parent e4c7884028
commit ec3c0982a2
9 changed files with 99 additions and 33 deletions
Download Patch File Download Diff File Expand all files Collapse all files

46
net/ipv4/tcp_input.c
View File

@@ -4451,6 +4451,49 @@ static void tcp_urg(struct sock *sk, struct sk_buff *skb, struct tcphdr *th)
}
}
static int tcp_defer_accept_check(struct sock *sk)
{
struct tcp_sock *tp = tcp_sk(sk);
if (tp->defer_tcp_accept.request) {
int queued_data = tp->rcv_nxt - tp->copied_seq;
int hasfin = !skb_queue_empty(&sk->sk_receive_queue) ?
tcp_hdr((struct sk_buff *)
sk->sk_receive_queue.prev)->fin : 0;
if (queued_data && hasfin)
queued_data--;
if (queued_data &&
tp->defer_tcp_accept.listen_sk->sk_state == TCP_LISTEN) {
if (sock_flag(sk, SOCK_KEEPOPEN)) {
inet_csk_reset_keepalive_timer(sk,
keepalive_time_when(tp));
} else {
inet_csk_delete_keepalive_timer(sk);
}
inet_csk_reqsk_queue_add(
tp->defer_tcp_accept.listen_sk,
tp->defer_tcp_accept.request,
sk);
tp->defer_tcp_accept.listen_sk->sk_data_ready(
tp->defer_tcp_accept.listen_sk, 0);
sock_put(tp->defer_tcp_accept.listen_sk);
sock_put(sk);
tp->defer_tcp_accept.listen_sk = NULL;
tp->defer_tcp_accept.request = NULL;
} else if (hasfin ||
tp->defer_tcp_accept.listen_sk->sk_state != TCP_LISTEN) {
tcp_reset(sk);
return -1;
}
}
return 0;
}
static int tcp_copy_to_iovec(struct sock *sk, struct sk_buff *skb, int hlen)
{
struct tcp_sock *tp = tcp_sk(sk);
@@ -4811,6 +4854,9 @@ step5:
tcp_data_snd_check(sk);
tcp_ack_snd_check(sk);
if (tcp_defer_accept_check(sk))
return -1;
return 0;
csum_error: