Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
[TCP]: Fix logic breakage due to DSACK separation
Commit 6f74651ae626ec672028587bc700538076dfbefb is found guilty
of breaking DSACK counting, which should be done only for the
SACK block reported by the DSACK instead of every SACK block
that is received along with DSACK information.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
authored by Ilpo Järvinen and committed by David S. Miller 7769f406 b9ce204f
+5
-4
net/ipv4/tcp_input.c
+5
-4
net/ipv4/tcp_input.c
···
953
int prior_fackets;
954
u32 lost_retrans = 0;
955
int flag = 0;
956
-
int dup_sack = 0;
957
int cached_fack_count;
958
int i;
959
int first_sack_index;
···
964
965
/* Check for D-SACK. */
966
if (before(ntohl(sp[0].start_seq), TCP_SKB_CB(ack_skb)->ack_seq)) {
967
-
dup_sack = 1;
968
tp->rx_opt.sack_ok |= 4;
969
NET_INC_STATS_BH(LINUX_MIB_TCPDSACKRECV);
970
} else if (num_sacks > 1 &&
971
!after(ntohl(sp[0].end_seq), ntohl(sp[1].end_seq)) &&
972
!before(ntohl(sp[0].start_seq), ntohl(sp[1].start_seq))) {
973
-
dup_sack = 1;
974
tp->rx_opt.sack_ok |= 4;
975
NET_INC_STATS_BH(LINUX_MIB_TCPDSACKOFORECV);
976
}
977
978
/* D-SACK for already forgotten data...
979
* Do dumb counting. */
980
-
if (dup_sack &&
981
!after(ntohl(sp[0].end_seq), prior_snd_una) &&
982
after(ntohl(sp[0].end_seq), tp->undo_marker))
983
tp->undo_retrans--;
···
1058
__u32 start_seq = ntohl(sp->start_seq);
1059
__u32 end_seq = ntohl(sp->end_seq);
1060
int fack_count;
1061
1062
skb = cached_skb;
1063
fack_count = cached_fack_count;
···
953
int prior_fackets;
954
u32 lost_retrans = 0;
955
int flag = 0;
956
+
int found_dup_sack = 0;
957
int cached_fack_count;
958
int i;
959
int first_sack_index;
···
964
965
/* Check for D-SACK. */
966
if (before(ntohl(sp[0].start_seq), TCP_SKB_CB(ack_skb)->ack_seq)) {
967
+
found_dup_sack = 1;
968
tp->rx_opt.sack_ok |= 4;
969
NET_INC_STATS_BH(LINUX_MIB_TCPDSACKRECV);
970
} else if (num_sacks > 1 &&
971
!after(ntohl(sp[0].end_seq), ntohl(sp[1].end_seq)) &&
972
!before(ntohl(sp[0].start_seq), ntohl(sp[1].start_seq))) {
973
+
found_dup_sack = 1;
974
tp->rx_opt.sack_ok |= 4;
975
NET_INC_STATS_BH(LINUX_MIB_TCPDSACKOFORECV);
976
}
977
978
/* D-SACK for already forgotten data...
979
* Do dumb counting. */
980
+
if (found_dup_sack &&
981
!after(ntohl(sp[0].end_seq), prior_snd_una) &&
982
after(ntohl(sp[0].end_seq), tp->undo_marker))
983
tp->undo_retrans--;
···
1058
__u32 start_seq = ntohl(sp->start_seq);
1059
__u32 end_seq = ntohl(sp->end_seq);
1060
int fack_count;
1061
+
int dup_sack = (found_dup_sack && (i == first_sack_index));
1062
1063
skb = cached_skb;
1064
fack_count = cached_fack_count;