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Fix some TCP fast open issues.

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The following issues are fixed:
* Whenever a TCP server with TCP fast open enabled, calls accept(),
  recv(), send(), and close() before the TCP-ACK segment has been received,
  the TCP connection is just dropped and the reception of the TCP-ACK
  segment triggers the sending of a TCP-RST segment.
* Whenever a TCP server with TCP fast open enabled, calls accept(), recv(),
  send(), send(), and close() before the TCP-ACK segment has been received,
  the first byte provided in the second send call is not transferred.
* Whenever a TCP client with TCP fast open enabled calls sendto() followed
  by close() the TCP connection is just dropped.

Reviewed by:		jtl@, kbowling@, rrs@
Sponsored by:		Netflix, Inc.
Differential Revision:	https://reviews.freebsd.org/D16485
This commit is contained in:
Michael Tuexen 2018-07-30 20:35:50 +00:00
parent 743d528198
commit 8db239dc6b
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=336934
3 changed files with 19 additions and 16 deletions
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20
sys/netinet/tcp_input.c
View File

@ -2407,6 +2407,16 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
* SYN-RECEIVED* -> FIN-WAIT-1
*/
tp->t_starttime = ticks;
if (IS_FASTOPEN(tp->t_flags) && tp->t_tfo_pending) {
tcp_fastopen_decrement_counter(tp->t_tfo_pending);
tp->t_tfo_pending = NULL;
/*
* Account for the ACK of our SYN prior to
* regular ACK processing below.
*/
tp->snd_una++;
}
if (tp->t_flags & TF_NEEDFIN) {
tcp_state_change(tp, TCPS_FIN_WAIT_1);
tp->t_flags &= ~TF_NEEDFIN;
@ -2414,16 +2424,6 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
tcp_state_change(tp, TCPS_ESTABLISHED);
TCP_PROBE5(accept__established, NULL, tp,
m, tp, th);
if (IS_FASTOPEN(tp->t_flags) && tp->t_tfo_pending) {
tcp_fastopen_decrement_counter(tp->t_tfo_pending);
tp->t_tfo_pending = NULL;
/*
* Account for the ACK of our SYN prior to
* regular ACK processing below.
*/
tp->snd_una++;
}
/*
* TFO connections call cc_conn_init() during SYN
* processing. Calling it again here for such

12
sys/netinet/tcp_output.c
View File

@ -228,13 +228,15 @@ tcp_output(struct tcpcb *tp)
#endif
/*
* For TFO connections in SYN_RECEIVED, only allow the initial
* SYN|ACK and those sent by the retransmit timer.
* For TFO connections in SYN_SENT or SYN_RECEIVED,
* only allow the initial SYN or SYN|ACK and those sent
* by the retransmit timer.
*/
if (IS_FASTOPEN(tp->t_flags) &&
(tp->t_state == TCPS_SYN_RECEIVED) &&
SEQ_GT(tp->snd_max, tp->snd_una) && /* initial SYN|ACK sent */
(tp->snd_nxt != tp->snd_una)) /* not a retransmit */
((tp->t_state == TCPS_SYN_SENT) ||
(tp->t_state == TCPS_SYN_RECEIVED)) &&
SEQ_GT(tp->snd_max, tp->snd_una) && /* initial SYN or SYN|ACK sent */
(tp->snd_nxt != tp->snd_una)) /* not a retransmit */
return (0);
/*

3
sys/netinet/tcp_usrreq.c
View File

@ -2113,7 +2113,8 @@ tcp_disconnect(struct tcpcb *tp)
* Neither tcp_close() nor tcp_drop() should return NULL, as the
* socket is still open.
*/
if (tp->t_state < TCPS_ESTABLISHED) {
if (tp->t_state < TCPS_ESTABLISHED &&
!(tp->t_state > TCPS_LISTEN && IS_FASTOPEN(tp->t_flags))) {
tp = tcp_close(tp);
KASSERT(tp != NULL,
("tcp_disconnect: tcp_close() returned NULL"));