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This is the second in a number of patches needed to

Browse Source 
get BBRv1 into the tree. This fixes the DSACK bug but
is also needed by BBR. We have yet to go two more
one will be for the pacing code (tcp_ratelimit.c) and
the second will be for the new updated LRO code that
allows a transport to know the arrival times of packets
and (tcp_lro.c). After that we should finally be able
to get BBRv1 into head.

Sponsored by:	Netflix Inc
Differential Revision:	https://reviews.freebsd.org/D20908
This commit is contained in:
rrs 2019-07-14 16:05:47 +00:00
parent eabf786dc9
commit 2bc1470fec
4 changed files with 50 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
sys/netinet/tcp_output.c
View File

@ -1508,7 +1508,13 @@ timer:
if (SEQ_GT(tp->snd_nxt + xlen, tp->snd_max))
tp->snd_max = tp->snd_nxt + xlen;
}
if ((error == 0) &&
(TCPS_HAVEESTABLISHED(tp->t_state) &&
(tp->t_flags & TF_SACK_PERMIT) &&
tp->rcv_numsacks > 0)) {
/* Clean up any DSACK's sent */
tcp_clean_dsack_blocks(tp);
}
if (error) {
/* Record the error. */
TCP_LOG_EVENT(tp, NULL, &so->so_rcv, &so->so_snd, TCP_LOG_OUT,

39
sys/netinet/tcp_sack.c
View File

@ -279,6 +279,45 @@ tcp_update_sack_list(struct tcpcb *tp, tcp_seq rcv_start, tcp_seq rcv_end)
tp->rcv_numsacks = num_head + num_saved;
}
void
tcp_clean_dsack_blocks(struct tcpcb *tp)
{
struct sackblk saved_blks[MAX_SACK_BLKS];
int num_saved, i;
INP_WLOCK_ASSERT(tp->t_inpcb);
/*
* Clean up any DSACK blocks that
* are in our queue of sack blocks.
*
*/
num_saved = 0;
for (i = 0; i < tp->rcv_numsacks; i++) {
tcp_seq start = tp->sackblks[i].start;
tcp_seq end = tp->sackblks[i].end;
if (SEQ_GEQ(start, end) || SEQ_LEQ(start, tp->rcv_nxt)) {
/*
* Discard this D-SACK block.
*/
continue;
}
/*
* Save this SACK block.
*/
saved_blks[num_saved].start = start;
saved_blks[num_saved].end = end;
num_saved++;
}
if (num_saved > 0) {
/*
* Copy the saved SACK blocks back.
*/
bcopy(saved_blks, &tp->sackblks[0],
sizeof(struct sackblk) * num_saved);
}
tp->rcv_numsacks = num_saved;
}
/*
* Delete all receiver-side SACK information.
*/

7
sys/netinet/tcp_stacks/rack.c
View File

@ -5087,9 +5087,8 @@ rack_do_fastnewdata(struct mbuf *m, struct tcphdr *th, struct socket *so,
/* Clean receiver SACK report if present */
/* if (tp->rcv_numsacks)
if (tp->rcv_numsacks)
tcp_clean_sackreport(tp);
*/
TCPSTAT_INC(tcps_preddat);
tp->rcv_nxt += tlen;
/*
@ -8537,10 +8536,10 @@ out:
* retransmit. In persist state, just set snd_max.
*/
if (error == 0) {
/* if (TCPS_HAVEESTABLISHED(tp->t_state) &&
if (TCPS_HAVEESTABLISHED(tp->t_state) &&
(tp->t_flags & TF_SACK_PERMIT) &&
tp->rcv_numsacks > 0)
tcp_clean_dsack_blocks(tp);*/
tcp_clean_dsack_blocks(tp);
if (len == 0)
counter_u64_add(rack_out_size[TCP_MSS_ACCT_SNDACK], 1);
else if (len == 1) {

1
sys/netinet/tcp_var.h
View File

@ -939,6 +939,7 @@ tcp_seq tcp_new_isn(struct in_conninfo *);
int tcp_sack_doack(struct tcpcb *, struct tcpopt *, tcp_seq);
void tcp_update_sack_list(struct tcpcb *tp, tcp_seq rcv_laststart, tcp_seq rcv_lastend);
void tcp_clean_dsack_blocks(struct tcpcb *tp);
void tcp_clean_sackreport(struct tcpcb *tp);
void tcp_sack_adjust(struct tcpcb *tp);
struct sackhole *tcp_sack_output(struct tcpcb *tp, int *sack_bytes_rexmt);