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tcp: improve handling of SYN segments in SYN-SENT state

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Ensure that the stack does not generate a DSACK block for user
data received on a SYN segment in SYN-SENT state.

Reviewed by:		rscheff
MFC after:		3 days
Differential Revision:	https://reviews.freebsd.org/D29376
Sponsored by:		Netflix, Inc.
This commit is contained in:
Michael Tuexen 2021-03-22 15:58:49 +01:00
parent f9a159da2a
commit 40f41ece76
3 changed files with 9 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
sys/netinet/tcp_input.c
View File

@ -3179,7 +3179,9 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
thflags = tcp_reass(tp, th, &temp, &tlen, m);
tp->t_flags |= TF_ACKNOW;
}
if ((tp->t_flags & TF_SACK_PERMIT) && (save_tlen > 0)) {
if ((tp->t_flags & TF_SACK_PERMIT) &&
(save_tlen > 0) &&
TCPS_HAVEESTABLISHED(tp->t_state)) {
if ((tlen == 0) && (SEQ_LT(save_start, save_rnxt))) {
/*
* DSACK actually handled in the fastpath

4
sys/netinet/tcp_stacks/bbr.c
View File

@ -8371,7 +8371,9 @@ bbr_process_data(struct mbuf *m, struct tcphdr *th, struct socket *so,
thflags = tcp_reass(tp, th, &temp, &tlen, m);
tp->t_flags |= TF_ACKNOW;
}
if ((tp->t_flags & TF_SACK_PERMIT) && (save_tlen > 0)) {
if ((tp->t_flags & TF_SACK_PERMIT) &&
(save_tlen > 0) &&
TCPS_HAVEESTABLISHED(tp->t_state)) {
if ((tlen == 0) && (SEQ_LT(save_start, save_rnxt))) {
/*
* DSACK actually handled in the fastpath

4
sys/netinet/tcp_stacks/rack.c
View File

@ -8683,7 +8683,9 @@ rack_process_data(struct mbuf *m, struct tcphdr *th, struct socket *so,
thflags = tcp_reass(tp, th, &temp, &tlen, m);
tp->t_flags |= TF_ACKNOW;
}
if ((tp->t_flags & TF_SACK_PERMIT) && (save_tlen > 0)) {
if ((tp->t_flags & TF_SACK_PERMIT) &&
(save_tlen > 0) &&
TCPS_HAVEESTABLISHED(tp->t_state)) {
if ((tlen == 0) && (SEQ_LT(save_start, save_rnxt))) {
/*
* DSACK actually handled in the fastpath