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Index: sys/netinet/tcp_input.c
===================================================================
--- sys/netinet/tcp_input.c
+++ sys/netinet/tcp_input.c
@@ -2262,7 +2262,11 @@
* DSACK - add SACK block for dropped range
*/
if (tp->t_flags & TF_SACK_PERMIT) {
- tcp_update_sack_list(tp, th->th_seq, th->th_seq+tlen);
+ /*
+ * up here, we only need to store the duplicated range
+ * as sackblk[0], for reference below during dsack
+ */
+ tcp_update_sack_list(tp, th->th_seq, th->th_seq+todrop);
/*
* ACK now, as the next in-sequence segment
* will clear the DSACK block again
@@ -3052,18 +3056,20 @@
tcp_update_sack_list(tp, save_start, save_start + save_tlen);
} else
if ((tlen > 0) && SEQ_GT(tp->rcv_nxt, save_rnxt)) {
- /*
- * Cleaning sackblks by using zero length
- * update.
- */
- tcp_update_sack_list(tp, save_start, save_start);
+ if ((tp->rcv_numsacks >= 1) &&
+ (tp->sackblks[0].end == save_start)) {
+ /* partial overlap */
+ tcp_update_sack_list(tp, tp->sackblks[0].start, tp->sackblks[0].end);
+ } else {
+ tcp_update_dsack_list(tp, save_start, save_start + save_tlen);
+ }
} else
if ((tlen > 0) && (tlen >= save_tlen)) {
/* Update of sackblks. */
- tcp_update_sack_list(tp, save_start, save_start + save_tlen);
+ tcp_update_dsack_list(tp, save_start, save_start + save_tlen);
} else
if (tlen > 0) {
- tcp_update_sack_list(tp, save_start, save_start+tlen);
+ tcp_update_dsack_list(tp, save_start, save_start+tlen);
}
}
#if 0
Index: sys/netinet/tcp_sack.c
===================================================================
--- sys/netinet/tcp_sack.c
+++ sys/netinet/tcp_sack.c
@@ -149,6 +149,108 @@
&VNET_NAME(tcp_sack_globalholes), 0,
"Global number of TCP SACK holes currently allocated");
+
+/*
+ * This function will find overlaps with the currently stored sackblocks
+ * and add any overlap as a dsack block upfront
+ */
+void
+tcp_update_dsack_list(struct tcpcb *tp, tcp_seq rcv_start, tcp_seq rcv_end)
+{
+ struct sackblk head_blk,mid_blk,saved_blks[MAX_SACK_BLKS];
+ int i, j, n, identical;
+ tcp_seq start, end;
+
+ INP_WLOCK_ASSERT(tp->t_inpcb);
+
+ KASSERT(SEQ_LT(rcv_start, rcv_end), ("rcv_start < rcv_end"));
+
+ if (tp->t_inpcb->inp_socket->so_options & SO_DEBUG) {
+ log(LOG_DEBUG, "\nDSACK update: %d..%d, rcv_nxt: %u\n",
+ rcv_start, rcv_end, tp->rcv_nxt);
+ }
+
+ if (SEQ_LT(rcv_end, tp->rcv_nxt) ||
+ ((rcv_end == tp->rcv_nxt) &&
+ (tp->rcv_numsacks > 0 ) &&
+ (tp->sackblks[0].end == tp->rcv_nxt))) {
+ saved_blks[0].start = rcv_start;
+ saved_blks[0].end = rcv_end;
+ } else {
+ saved_blks[0].start = saved_blks[0].end = 0;
+ }
+
+ head_blk.start = head_blk.end = 0;
+ mid_blk.start = rcv_start;
+ mid_blk.end = rcv_end;
+ identical = 0;
+
+ for (i = 0; i < tp->rcv_numsacks; i++) {
+ start = tp->sackblks[i].start;
+ end = tp->sackblks[i].end;
+ if (SEQ_LT(rcv_end, start)) {
+ /* pkt left to sack blk */
+ continue;
+ }
+ if (SEQ_GT(rcv_start, end)) {
+ /* pkt right to sack blk */
+ continue;
+ }
+ if (SEQ_GT(tp->rcv_nxt, end)) {
+ if ((SEQ_MAX(rcv_start, start) != SEQ_MIN(rcv_end, end)) &&
+ (SEQ_GT(head_blk.start, SEQ_MAX(rcv_start, start)) ||
+ (head_blk.start == head_blk.end))) {
+ head_blk.start = SEQ_MAX(rcv_start, start);
+ head_blk.end = SEQ_MIN(rcv_end, end);
+ }
+ continue;
+ }
+ if (((head_blk.start == head_blk.end) ||
+ SEQ_LT(start, head_blk.start)) &&
+ (SEQ_GT(end, rcv_start) &&
+ SEQ_LEQ(start, rcv_end))) {
+ head_blk.start = start;
+ head_blk.end = end;
+ }
+ mid_blk.start = SEQ_MIN(mid_blk.start, start);
+ mid_blk.end = SEQ_MAX(mid_blk.end, end);
+ if ((mid_blk.start == start) &&
+ (mid_blk.end == end))
+ identical = 1;
+ }
+ if (SEQ_LT(head_blk.start, head_blk.end)) {
+ /* store overlapping range */
+ saved_blks[0].start = SEQ_MAX(rcv_start, head_blk.start);
+ saved_blks[0].end = SEQ_MIN(rcv_end, head_blk.end);
+ }
+ n=1;
+ /*
+ * Second, if not ACKed, store the SACK block that
+ * overlaps with the DSACK block unless it is identical
+ */
+ if ((SEQ_LT(tp->rcv_nxt, mid_blk.end) &&
+ !((mid_blk.start == saved_blks[0].start) &&
+ (mid_blk.end == saved_blks[0].end))) ||
+ identical == 1) {
+ saved_blks[n].start = mid_blk.start;
+ saved_blks[n++].end = mid_blk.end;
+ }
+ for (j = 0; (j < tp->rcv_numsacks) && (j < MAX_SACK_BLKS-1); j++) {
+ if (((SEQ_LT(tp->sackblks[j].end, mid_blk.start) ||
+ SEQ_GT(tp->sackblks[j].start, mid_blk.end)) &&
+ (SEQ_GT(tp->sackblks[j].start, tp->rcv_nxt))))
+ saved_blks[n++] = tp->sackblks[j];
+ }
+ j=0;
+ for (i=0; i<n; i++) {
+ /* we can end up with a stale inital entry */
+ if (SEQ_LT(saved_blks[i].start, saved_blks[i].end)) {
+ tp->sackblks[j++] = saved_blks[i];
+ }
+ }
+ tp->rcv_numsacks = j;
+}
+
/*
* This function is called upon receipt of new valid data (while not in
* header prediction mode), and it updates the ordered list of sacks.
@@ -170,9 +272,16 @@
/* Check arguments. */
KASSERT(SEQ_LEQ(rcv_start, rcv_end), ("rcv_start <= rcv_end"));
+ if ((rcv_start == rcv_end) &&
+ (tp->rcv_numsacks >= 1) &&
+ (rcv_start == tp->sackblks[0].end)) {
+ head_blk = tp->sackblks[0];
+ } else {
+
/* SACK block for the received segment. */
head_blk.start = rcv_start;
head_blk.end = rcv_end;
+ }
/*
* Merge updated SACK blocks into head_blk, and save unchanged SACK
@@ -267,6 +376,10 @@
if (num_saved >= MAX_SACK_BLKS)
num_saved--;
}
+ if ((rcv_start == rcv_end) &&
+ (rcv_start == tp->sackblks[0].end)) {
+ num_head = 1;
+ }
if (num_saved > 0) {
/*
* Copy the saved SACK blocks back.
Index: sys/netinet/tcp_stacks/rack.c
===================================================================
--- sys/netinet/tcp_stacks/rack.c
+++ sys/netinet/tcp_stacks/rack.c
@@ -1787,6 +1787,14 @@
TCPSTAT_INC(tcps_rcvpartduppack);
TCPSTAT_ADD(tcps_rcvpartdupbyte, todrop);
}
+ if (tp->t_flags & TF_SACK_PERMIT) {
+ /*
+ * record the left, to-be-dropped edge of data
+ * here, for use as dsack block further down
+ */
+ tcp_update_sack_list(tp, th->th_seq,
+ th->th_seq + todrop);
+ }
*drop_hdrlen += todrop; /* drop from the top afterwards */
th->th_seq += todrop;
tlen -= todrop;
@@ -4944,12 +4952,22 @@
* Cleaning sackblks by using zero length
* update.
*/
- tcp_update_sack_list(tp, save_start, save_start);
+ if ((tp->rcv_numsacks >= 1) &&
+ (tp->sackblks[0].end == save_start)) {
+ /* partial overlap, recorded at todrop above */
+ tcp_update_sack_list(tp, tp->sackblks[0].start,
+ tp->sackblks[0].end);
+ } else {
+ tcp_update_dsack_list(tp, save_start,
+ save_start + save_tlen);
+ }
} else if ((tlen > 0) && (tlen >= save_tlen)) {
/* Update of sackblks. */
- tcp_update_sack_list(tp, save_start, save_start + save_tlen);
+ tcp_update_dsack_list(tp, save_start,
+ save_start + save_tlen);
} else if (tlen > 0) {
- tcp_update_sack_list(tp, save_start, save_start+tlen);
+ tcp_update_dsack_list(tp, save_start,
+ save_start + tlen);
}
} else {
m_freem(m);
Index: sys/netinet/tcp_var.h
===================================================================
--- sys/netinet/tcp_var.h
+++ sys/netinet/tcp_var.h
@@ -938,6 +938,7 @@
tcp_seq tcp_new_isn(struct in_conninfo *);
int tcp_sack_doack(struct tcpcb *, struct tcpopt *, tcp_seq);
+void tcp_update_dsack_list(struct tcpcb *, tcp_seq, 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);

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