PERFORCE change 165925 for review
Andre Oppermann
andre at FreeBSD.org
Sat Jul 11 10:34:04 UTC 2009
http://perforce.freebsd.org/chv.cgi?CH=165925
Change 165925 by andre at andre_t61 on 2009/07/11 10:33:34
Try a different approach to the SACK scoreboard using a ranged RB-tree instead of a TAILQ.
The maintenance of the scoreboard is much simpler.
Affected files ...
.. //depot/projects/tcp_new/netinet/tcp_sack.c#3 edit
.. //depot/projects/tcp_new/netinet/tcp_subr.c#6 edit
.. //depot/projects/tcp_new/netinet/tcp_var.h#11 edit
Differences ...
==== //depot/projects/tcp_new/netinet/tcp_sack.c#3 (text+ko) ====
@@ -1,6 +1,6 @@
/*-
- * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994, 1995
- * The Regents of the University of California.
+ * Copyright (c) 2009
+ * Andre Oppermann, Internet Business Solutions AG.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
@@ -11,7 +11,7 @@
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
- * 4. Neither the name of the University nor the names of its contributors
+ * 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
@@ -30,46 +30,6 @@
* @(#)tcp_sack.c 8.12 (Berkeley) 5/24/95
*/
-/*-
- * @@(#)COPYRIGHT 1.1 (NRL) 17 January 1995
- *
- * NRL grants permission for redistribution and use in source and binary
- * forms, with or without modification, of the software and documentation
- * created at NRL provided that the following conditions are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- * must display the following acknowledgements:
- * This product includes software developed by the University of
- * California, Berkeley and its contributors.
- * This product includes software developed at the Information
- * Technology Division, US Naval Research Laboratory.
- * 4. Neither the name of the NRL nor the names of its contributors
- * may be used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * THE SOFTWARE PROVIDED BY NRL IS PROVIDED BY NRL AND CONTRIBUTORS ``AS
- * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
- * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
- * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL NRL OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
- * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
- * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
- * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
- * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
- * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- * The views and conclusions contained in the software and documentation
- * are those of the authors and should not be interpreted as representing
- * official policies, either expressed or implied, of the US Naval
- * Research Laboratory (NRL).
- */
-
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/netinet/tcp_sack.c,v 1.40 2007/05/11 11:21:43 rwatson Exp $");
@@ -119,11 +79,12 @@
#include <netinet/tcp_debug.h>
#endif /* TCPDEBUG */
-#include <machine/in_cksum.h>
+/*
+ * Store all SACK blocks of the scoreboard in a ranged red-black tree.
+ */
-extern struct uma_zone *sack_hole_zone;
+SYSCTL_NODE(_net_inet_tcp, OID_AUTO, sack, CTLFLAG_RW, 0, "TCP SACK");
-SYSCTL_NODE(_net_inet_tcp, OID_AUTO, sack, CTLFLAG_RW, 0, "TCP SACK");
int tcp_do_sack = 1;
SYSCTL_INT(_net_inet_tcp_sack, OID_AUTO, enable, CTLFLAG_RW,
&tcp_do_sack, 0, "Enable/Disable TCP SACK support");
@@ -139,544 +100,168 @@
&tcp_sack_globalmaxholes, 0,
"Global maximum number of TCP SACK holes");
-static int tcp_sack_globalholes = 0;
-SYSCTL_INT(_net_inet_tcp_sack, OID_AUTO, globalholes, CTLFLAG_RD,
- &tcp_sack_globalholes, 0,
- "Global number of TCP SACK holes currently allocated");
+static uma_zone_t tcp_sackblock_zone;
-/*
- * This function is called upon receipt of new valid data (while not in
- * header prediction mode), and it updates the ordered list of sacks.
- */
void
-tcp_update_sack_list(struct tcpcb *tp, tcp_seq rcv_start, tcp_seq rcv_end)
+tcp_sack_init(void)
{
- /*
- * First reported block MUST be the most recent one. Subsequent
- * blocks SHOULD be in the order in which they arrived at the
- * receiver. These two conditions make the implementation fully
- * compliant with RFC 2018.
- */
- struct sackblk head_blk, saved_blks[MAX_SACK_BLKS];
- int num_head, num_saved, i;
-
- INP_LOCK_ASSERT(tp->t_inpcb);
-
- /* Check arguments. */
- KASSERT(SEQ_LT(rcv_start, rcv_end), ("rcv_start < rcv_end"));
-
- /* 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
- * blocks into saved_blks[]. num_saved will have the number of the
- * saved 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 SACK block.
- */
- } else if (SEQ_LEQ(head_blk.start, end) &&
- SEQ_GEQ(head_blk.end, start)) {
- /*
- * Merge this SACK block into head_blk. This SACK
- * block itself will be discarded.
- */
- if (SEQ_GT(head_blk.start, start))
- head_blk.start = start;
- if (SEQ_LT(head_blk.end, end))
- head_blk.end = end;
- } else {
- /*
- * Save this SACK block.
- */
- saved_blks[num_saved].start = start;
- saved_blks[num_saved].end = end;
- num_saved++;
- }
- }
-
- /*
- * Update SACK list in tp->sackblks[].
- */
- num_head = 0;
- if (SEQ_GT(head_blk.start, tp->rcv_nxt)) {
- /*
- * The received data segment is an out-of-order segment. Put
- * head_blk at the top of SACK list.
- */
- tp->sackblks[0] = head_blk;
- num_head = 1;
- /*
- * If the number of saved SACK blocks exceeds its limit,
- * discard the last SACK block.
- */
- if (num_saved >= MAX_SACK_BLKS)
- num_saved--;
- }
- if (num_saved > 0) {
- /*
- * Copy the saved SACK blocks back.
- */
- bcopy(saved_blks, &tp->sackblks[num_head],
- sizeof(struct sackblk) * num_saved);
- }
-
- /* Save the number of SACK blocks. */
- tp->rcv_numsacks = num_head + num_saved;
+ tcp_sackblock_zone = uma_zcreate("tcpsackblk", sizeof(struct tcp_sack_block),
+ NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
+ uma_zone_set_max(tcp_sackblock_zone, tcp_sack_globalmaxholes);
}
-/*
- * Delete all receiver-side SACK information.
- */
-void
-tcp_clean_sackreport(struct tcpcb *tp)
+static __inline int
+tcp_sack_cmp(struct tcp_sack_block *a, struct tcp_sack_block *b)
{
- int i;
-
- INP_LOCK_ASSERT(tp->t_inpcb);
- tp->rcv_numsacks = 0;
- for (i = 0; i < MAX_SACK_BLKS; i++)
- tp->sackblks[i].start = tp->sackblks[i].end=0;
+ if (SEQ_LT(a->tsb_blk.end, b->tsb_blk.start))
+ return (-1);
+ else if (SEQ_GT(a->tsb_blk.start, b->tsb_blk.end))
+ return (1);
+ else
+ return (0);
}
-/*
- * Allocate struct sackhole.
- */
-static struct sackhole *
-tcp_sackhole_alloc(struct tcpcb *tp, tcp_seq start, tcp_seq end)
-{
- struct sackhole *hole;
-
- if (tp->snd_numholes >= tcp_sack_maxholes ||
- tcp_sack_globalholes >= tcp_sack_globalmaxholes) {
- tcpstat.tcps_sack_sboverflow++;
- return NULL;
- }
-
- hole = (struct sackhole *)uma_zalloc(sack_hole_zone, M_NOWAIT);
- if (hole == NULL)
- return NULL;
-
- hole->start = start;
- hole->end = end;
- hole->rxmit = start;
+RB_PROTOTYPE(tcp_sackblocks, tcp_sack_block, tsb_rb, tcp_sack_cmp);
+RB_GENERATE(tcp_sackblocks, tcp_sack_block, tsb_rb, tcp_sack_cmp);
- tp->snd_numholes++;
- tcp_sack_globalholes++;
-
- return hole;
-}
-
-/*
- * Free struct sackhole.
- */
static void
-tcp_sackhole_free(struct tcpcb *tp, struct sackhole *hole)
+tcp_sack_free(struct tcp_sack_block *tps, struct tcp_sack_block *tsb)
{
+ struct tcp_sack_block *sb;
- uma_zfree(sack_hole_zone, hole);
-
- tp->snd_numholes--;
- tcp_sack_globalholes--;
-
- KASSERT(tp->snd_numholes >= 0, ("tp->snd_numholes >= 0"));
- KASSERT(tcp_sack_globalholes >= 0, ("tcp_sack_globalholes >= 0"));
+ sb = RB_REMOVE(tcp_sackholes, tps, tsb);
+ KASSERT(sb != NULL, ("%s: RB_REMOVE failed", __func__));
+ uma_zfree(tcp_sackblock_zone, tsb);
}
-/*
- * Insert new SACK hole into scoreboard.
- */
-static struct sackhole *
-tcp_sackhole_insert(struct tcpcb *tp, tcp_seq start, tcp_seq end,
- struct sackhole *after)
+#ifdef INVARIANTS
+static int
+tcp_sack_verify(struct tcpcb *tp)
{
- struct sackhole *hole;
+ struct tcp_sack_block *tsb, *tsbn;
- /* Allocate a new SACK hole. */
- hole = tcp_sackhole_alloc(tp, start, end);
- if (hole == NULL)
- return NULL;
-
- /* Insert the new SACK hole into scoreboard. */
- if (after != NULL)
- TAILQ_INSERT_AFTER(&tp->snd_holes, after, hole, scblink);
- else
- TAILQ_INSERT_TAIL(&tp->snd_holes, hole, scblink);
-
- /* Update SACK hint. */
- if (tp->sackhint.nexthole == NULL)
- tp->sackhint.nexthole = hole;
-
- return hole;
+ RB_FOREACH_SAFE(tsb, tcp_sackblocks, &tp->snd_sackblocks, tsbn) {
+ if (SEQ_GEQ(tsb->tsb_blk.start, tsb->tsb_blk.end) ||
+ SEQ_LEQ(tsb->tsb_blk.start, tp->snd_una) ||
+ SEQ_GT(tsb->tsb_blk.end, tp->snd_nxt) ||
+ (tsbn != NULL && SEQ_GEQ(tsb->tsb_blk.end, tsbn->tsb_blk.start)))
+ return (0)
+ }
+ return (1);
}
-
-/*
- * Remove SACK hole from scoreboard.
- */
-static void
-tcp_sackhole_remove(struct tcpcb *tp, struct sackhole *hole)
-{
+#endif
- /* Update SACK hint. */
- if (tp->sackhint.nexthole == hole)
- tp->sackhint.nexthole = TAILQ_NEXT(hole, scblink);
-
- /* Remove this SACK hole. */
- TAILQ_REMOVE(&tp->snd_holes, hole, scblink);
-
- /* Free this SACK hole. */
- tcp_sackhole_free(tp, hole);
-}
-
-/*
- * Process cumulative ACK and the TCP SACK option to update the scoreboard.
- * tp->snd_holes is an ordered list of holes (oldest to newest, in terms of
- * the sequence space).
- */
int
tcp_sack_doack(struct tcpcb *tp, struct tcpopt *to, tcp_seq th_ack)
{
- struct sackhole *cur, *temp;
- struct sackblk sack, sack_blocks[TCP_MAX_SACK + 1], *sblkp;
- int i, j, num_sack_blks;
+ int i;
+ int sacked = 0; /* the amount of newly sacked data */
+ struct tcp_sack_block *tsb, *tsbn;
+ struct tcp_sack_block sack;
- INP_LOCK_ASSERT(tp->t_inpcb);
+ /* Remove any blocks from the scoreboard when full acked. */
+ RB_FOREACH_SAFE(tsb, tcp_sackblocks, &tp->snd_sackblocks, tsbn) {
+ if (SEQ_LT(th_ack, tqe->tsb_blk.start))
+ break;
+ else
+ RB_REMOVE(tcp_sackblocks, &tp->snd_sackblocks, tsb);
+ }
- num_sack_blks = 0;
- /*
- * If SND.UNA will be advanced by SEG.ACK, and if SACK holes exist,
- * treat [SND.UNA, SEG.ACK) as if it is a SACK block.
- */
- if (SEQ_LT(tp->snd_una, th_ack) && !TAILQ_EMPTY(&tp->snd_holes)) {
- sack_blocks[num_sack_blks].start = tp->snd_una;
- sack_blocks[num_sack_blks++].end = th_ack;
- }
- /*
- * Append received valid SACK blocks to sack_blocks[], but only if we
- * received new blocks from the other side.
- */
- if (to->to_flags & TOF_SACK) {
- for (i = 0; i < to->to_nsacks; i++) {
- bcopy((to->to_sacks + i * TCPOLEN_SACK),
- &sack, sizeof(sack));
- sack.start = ntohl(sack.start);
- sack.end = ntohl(sack.end);
- if (SEQ_GT(sack.end, sack.start) &&
- SEQ_GT(sack.start, tp->snd_una) &&
- SEQ_GT(sack.start, th_ack) &&
- SEQ_LT(sack.start, tp->snd_nxt) &&
- SEQ_GT(sack.end, tp->snd_una) &&
- SEQ_LEQ(sack.end, tp->snd_nxt))
- sack_blocks[num_sack_blks++] = sack;
- }
- }
- /*
- * Return if SND.UNA is not advanced and no valid SACK block is
- * received.
- */
- if (num_sack_blks == 0)
+ if ((to->t_flags & TOF_SACK) && to->to_nsacks == 0) {
+ /* remove all sack blocks, strange reneg */
+ tcp_sack_flush(tp);
+ return (0);
+ } else if (!(to->t_flags & TOF_SACK))
return (0);
- /*
- * Sort the SACK blocks so we can update the scoreboard with just one
- * pass. The overhead of sorting upto 4+1 elements is less than
- * making upto 4+1 passes over the scoreboard.
- */
- for (i = 0; i < num_sack_blks; i++) {
- for (j = i + 1; j < num_sack_blks; j++) {
- if (SEQ_GT(sack_blocks[i].end, sack_blocks[j].end)) {
- sack = sack_blocks[i];
- sack_blocks[i] = sack_blocks[j];
- sack_blocks[j] = sack;
- }
- }
- }
- if (TAILQ_EMPTY(&tp->snd_holes))
- /*
- * Empty scoreboard. Need to initialize snd_fack (it may be
- * uninitialized or have a bogus value). Scoreboard holes
- * (from the sack blocks received) are created later below
- * (in the logic that adds holes to the tail of the
- * scoreboard).
- */
- tp->snd_fack = SEQ_MAX(tp->snd_una, th_ack);
- /*
- * In the while-loop below, incoming SACK blocks (sack_blocks[]) and
- * SACK holes (snd_holes) are traversed from their tails with just
- * one pass in order to reduce the number of compares especially when
- * the bandwidth-delay product is large.
- *
- * Note: Typically, in the first RTT of SACK recovery, the highest
- * three or four SACK blocks with the same ack number are received.
- * In the second RTT, if retransmitted data segments are not lost,
- * the highest three or four SACK blocks with ack number advancing
- * are received.
- */
- sblkp = &sack_blocks[num_sack_blks - 1]; /* Last SACK block */
- if (SEQ_LT(tp->snd_fack, sblkp->start)) {
- /*
- * The highest SACK block is beyond fack. Append new SACK
- * hole at the tail. If the second or later highest SACK
- * blocks are also beyond the current fack, they will be
- * inserted by way of hole splitting in the while-loop below.
- */
- temp = tcp_sackhole_insert(tp, tp->snd_fack,sblkp->start,NULL);
- if (temp != NULL) {
- tp->snd_fack = sblkp->end;
- /* Go to the previous sack block. */
- sblkp--;
- } else {
- /*
- * We failed to add a new hole based on the current
- * sack block. Skip over all the sack blocks that
- * fall completely to the right of snd_fack and
- * proceed to trim the scoreboard based on the
- * remaining sack blocks. This also trims the
- * scoreboard for th_ack (which is sack_blocks[0]).
- */
- while (sblkp >= sack_blocks &&
- SEQ_LT(tp->snd_fack, sblkp->start))
- sblkp--;
- if (sblkp >= sack_blocks &&
- SEQ_LT(tp->snd_fack, sblkp->end))
- tp->snd_fack = sblkp->end;
- }
- } else if (SEQ_LT(tp->snd_fack, sblkp->end))
- /* fack is advanced. */
- tp->snd_fack = sblkp->end;
- /* We must have at least one SACK hole in scoreboard. */
- KASSERT(!TAILQ_EMPTY(&tp->snd_holes),
- ("SACK scoreboard must not be empty"));
- cur = TAILQ_LAST(&tp->snd_holes, sackhole_head); /* Last SACK hole. */
- /*
- * Since the incoming sack blocks are sorted, we can process them
- * making one sweep of the scoreboard.
- */
- while (sblkp >= sack_blocks && cur != NULL) {
- if (SEQ_GEQ(sblkp->start, cur->end)) {
- /*
- * SACKs data beyond the current hole. Go to the
- * previous sack block.
- */
- sblkp--;
+ /* Integrate SACK blocks from segment. */
+ for (i = 0; i < to->to_nsacks; i++) {
+ /* Copy SACK blocks from options section of TCP header. */
+ bcopy((to->to_sacks + i * TCPOLEN_SACK),
+ &sack.tsb_blk, sizeof(sack.tsb_blk));
+ sack.tsb_blk.start = ntohl(sack.tsb_blk.start);
+ sack.tsb_blk.end = ntohl(sack.tsb_blk.end);
+
+ /* Validity checks on SACK blocks as received from sender. */
+ if (SEQ_GT(sack.tsb_blk.start, sack.tsb_blk.end) ||
+ SEQ_LEQ(sack.tsb_blk.start, th_ack) ||
+ SEQ_GT(sack.tsb_blk.end, tp->snd_nxt))
continue;
- }
- if (SEQ_LEQ(sblkp->end, cur->start)) {
- /*
- * SACKs data before the current hole. Go to the
- * previous hole.
- */
- cur = TAILQ_PREV(cur, sackhole_head, scblink);
+
+ /* XXXAO: Implicit-explicit reneg. */
+ if (sack.start == sack.end) {
+ /* Remove all sackblocks. */
+ tcp_sack_flush(tp);
continue;
}
- tp->sackhint.sack_bytes_rexmit -= (cur->rxmit - cur->start);
- KASSERT(tp->sackhint.sack_bytes_rexmit >= 0,
- ("sackhint bytes rtx >= 0"));
- if (SEQ_LEQ(sblkp->start, cur->start)) {
- /* Data acks at least the beginning of hole. */
- if (SEQ_GEQ(sblkp->end, cur->end)) {
- /* Acks entire hole, so delete hole. */
- temp = cur;
- cur = TAILQ_PREV(cur, sackhole_head, scblink);
- tcp_sackhole_remove(tp, temp);
- /*
- * The sack block may ack all or part of the
- * next hole too, so continue onto the next
- * hole.
- */
+
+ /* Return match that has at least partial overlap to either side. */
+ if ((tsb = RB_FIND(tcp_sackblocks, &tp->snd_sackblocks, &sack)) != NULL) {
+ /* within a block, was a duplicate retransmit, D-SACK */
+ if (SEQ_GEQ(sack.tsb_blk.start, tsb->tsb_blk.start) &&
+ SEQ_LEQ(sack.tsb_blk.end, tsb->tsb_blk.end)) {
continue;
- } else {
- /* Move start of hole forward. */
- cur->start = sblkp->end;
- cur->rxmit = SEQ_MAX(cur->rxmit, cur->start);
+ }
+ /* Extends the end, common case. */
+ if (SEQ_GT(sack.tsb_blk.end, tsb->tsb_blk.end)) {
+ sacked += SEQ_DELTA(tsb->tsb_blk.end, sack.tsb_blk.end);
+ tsb->tsb_blk.end = sack.tsb_blk.end;
+ while ((tsbn = RB_NEXT(tcp_sackblocks, &tp->snd_sackblocks, tsb)) != NULL &&
+ SEQ_GEQ(tsbn->tsb_blk.start, tsb->tsb_blk.end)) {
+ //sacked -= SEQ_DELTA(sack.tsb_blk.start, tsbn->tsb_blk.start);
+ if (SEQ_GT(tsbn->tsb_blk.end, tsb->tsb_blk.end))
+ tsb->tsb_blk.end = tsbn->tsb_blk.end;
+ tcp_sack_free(&tp->snd_sackblocks, tsbn);
+ }
}
- } else {
- /* Data acks at least the end of hole. */
- if (SEQ_GEQ(sblkp->end, cur->end)) {
- /* Move end of hole backward. */
- cur->end = sblkp->start;
- cur->rxmit = SEQ_MIN(cur->rxmit, cur->end);
- } else {
- /*
- * ACKs some data in middle of a hole; need
- * to split current hole
- */
- temp = tcp_sackhole_insert(tp, sblkp->end,
- cur->end, cur);
- if (temp != NULL) {
- if (SEQ_GT(cur->rxmit, temp->rxmit)) {
- temp->rxmit = cur->rxmit;
- tp->sackhint.sack_bytes_rexmit
- += (temp->rxmit
- - temp->start);
- }
- cur->end = sblkp->start;
- cur->rxmit = SEQ_MIN(cur->rxmit,
- cur->end);
+ /* Extends the start. */
+ if (SEQ_LT(sack.tsb_blk.start, tsb->tsb_blk.start)) {
+ sacked += SEQ_DELTA(sack.tsb_blk.start, tsb->tsb_blk.start);
+ tsb->tsb_blk.start = sack.tsb_blk.start;
+ while ((tsbn = RB_PREV(tcp_sackblocks, &tp->snd_sackblocks, tsb)) != NULL &&
+ SEQ_GEQ(tsbn->tsb_blk.end, tsb->tsb_blk.start)) {
+ //sacked -= SEQ_DELTA();
+ if (SEQ_LT(tsbn->tsb_blk.start, tsb->tsb_blk.start))
+ tsb->tsb_blk.start = tsbn->tsb_blk.start;
+ tcp_sack_free(&tp->snd_sackblocks, tsbn);
}
}
- }
- tp->sackhint.sack_bytes_rexmit += (cur->rxmit - cur->start);
- /*
- * Testing sblkp->start against cur->start tells us whether
- * we're done with the sack block or the sack hole.
- * Accordingly, we advance one or the other.
- */
- if (SEQ_LEQ(sblkp->start, cur->start))
- cur = TAILQ_PREV(cur, sackhole_head, scblink);
- else
- sblkp--;
+ } else if ((tsb = (struct sackblocks *)uma_zalloc(tcp_sackblock_zone, M_NOWAIT))) != NULL) {
+ sacked += SEQ_DELTA(sack.tsb_blk.start, sack.tsb_blk.end);
+ tsb->tsb_blk.start = sack.tsb_blk.start;
+ tsb->tsb_blk.end = sack.tsb_blk.end;
+ tsbn = RB_INSERT(tcp_sackblocks, &tp->snd_sackblocks, tsb);
+ KASSERT(tsbn == NULL, ("%s: RB_INSERT failed", __func__));
+ } else
+ TCPSTAT_INC(); /* failed to allocate sackblock */
}
- return (0);
-}
-/*
- * Free all SACK holes to clear the scoreboard.
- */
-void
-tcp_free_sackholes(struct tcpcb *tp)
-{
- struct sackhole *q;
+ KASSERT(tcp_sack_verify(tp),
+ ("%s: snd_sackblocks RB tree inconsistent", __func__));
- INP_LOCK_ASSERT(tp->t_inpcb);
- while ((q = TAILQ_FIRST(&tp->snd_holes)) != NULL)
- tcp_sackhole_remove(tp, q);
- tp->sackhint.sack_bytes_rexmit = 0;
-
- KASSERT(tp->snd_numholes == 0, ("tp->snd_numholes == 0"));
- KASSERT(tp->sackhint.nexthole == NULL,
- ("tp->sackhint.nexthole == NULL"));
+ return (sacked);
}
-/*
- * Partial ack handling within a sack recovery episode. Keeping this very
- * simple for now. When a partial ack is received, force snd_cwnd to a value
- * that will allow the sender to transmit no more than 2 segments. If
- * necessary, a better scheme can be adopted at a later point, but for now,
- * the goal is to prevent the sender from bursting a large amount of data in
- * the midst of sack recovery.
- */
void
-tcp_sack_partialack(struct tcpcb *tp, struct tcphdr *th)
+tcp_sack_flush(struct tcpcb *tp)
{
- int num_segs = 1;
+ struct tcp_sack_block *tsb, *tsbn;
- INP_LOCK_ASSERT(tp->t_inpcb);
- tcp_timer_activate(tp, TT_REXMT, 0);
- //tp->t_rtttime = 0;
- /* Send one or 2 segments based on how much new data was acked. */
- if (((th->th_ack - tp->snd_una) / tp->snd_mss) > 2)
- num_segs = 2;
- tp->snd_cwnd = (tp->sackhint.sack_bytes_rexmit +
- (tp->snd_nxt - tp->sack_newdata) + num_segs * tp->snd_mss);
- if (tp->snd_cwnd > tp->snd_ssthresh)
- tp->snd_cwnd = tp->snd_ssthresh;
- tp->t_flags |= TF_ACKNOW;
- (void) tcp_output(tp);
-}
-
-#if 0
-/*
- * Debug version of tcp_sack_output() that walks the scoreboard. Used for
- * now to sanity check the hint.
- */
-static struct sackhole *
-tcp_sack_output_debug(struct tcpcb *tp, int *sack_bytes_rexmt)
-{
- struct sackhole *p;
-
- INP_LOCK_ASSERT(tp->t_inpcb);
- *sack_bytes_rexmt = 0;
- TAILQ_FOREACH(p, &tp->snd_holes, scblink) {
- if (SEQ_LT(p->rxmit, p->end)) {
- if (SEQ_LT(p->rxmit, tp->snd_una)) {/* old SACK hole */
- continue;
- }
- *sack_bytes_rexmt += (p->rxmit - p->start);
- break;
- }
- *sack_bytes_rexmt += (p->rxmit - p->start);
+ RB_FOREACH_SAFE(tsb, tcp_sackholes, &tp->snd_sackholes, tsbn) {
+ RB_REMOVE(tcp_sackholes, &tp->snd_sackholes, tsb);
+ uma_zfree(tcp_sackbock_zone, tsb);
}
- return (p);
}
-#endif
-/*
- * Returns the next hole to retransmit and the number of retransmitted bytes
- * from the scoreboard. We store both the next hole and the number of
- * retransmitted bytes as hints (and recompute these on the fly upon SACK/ACK
- * reception). This avoids scoreboard traversals completely.
- *
- * The loop here will traverse *at most* one link. Here's the argument. For
- * the loop to traverse more than 1 link before finding the next hole to
- * retransmit, we would need to have at least 1 node following the current
- * hint with (rxmit == end). But, for all holes following the current hint,
- * (start == rxmit), since we have not yet retransmitted from them.
- * Therefore, in order to traverse more 1 link in the loop below, we need to
- * have at least one node following the current hint with (start == rxmit ==
- * end). But that can't happen, (start == end) means that all the data in
- * that hole has been sacked, in which case, the hole would have been removed
- * from the scoreboard.
- */
-struct sackhole *
-tcp_sack_output(struct tcpcb *tp, int *sack_bytes_rexmt)
+#ifdef DDB
+static void
+db_print_sackblocks(struct tcpcb *tp)
{
- struct sackhole *hole = NULL;
+ struct tcp_sack_block *tsb;
- INP_LOCK_ASSERT(tp->t_inpcb);
- *sack_bytes_rexmt = tp->sackhint.sack_bytes_rexmit;
- hole = tp->sackhint.nexthole;
- if (hole == NULL || SEQ_LT(hole->rxmit, hole->end))
- goto out;
- while ((hole = TAILQ_NEXT(hole, scblink)) != NULL) {
- if (SEQ_LT(hole->rxmit, hole->end)) {
- tp->sackhint.nexthole = hole;
- break;
- }
+ RB_FOREACH(tsb, tcp_sackblocks, &tp->snd_sackblocks) {
+ db_printf(" sack block 0x%08x - 0x%08x\n",
+ tsb->tsb_blk.start, tsb->tsb_blk.end)
}
-out:
- return (hole);
}
-
-/*
- * After a timeout, the SACK list may be rebuilt. This SACK information
- * should be used to avoid retransmitting SACKed data. This function
- * traverses the SACK list to see if snd_nxt should be moved forward.
- */
-void
-tcp_sack_adjust(struct tcpcb *tp)
-{
- struct sackhole *p, *cur = TAILQ_FIRST(&tp->snd_holes);
-
- INP_LOCK_ASSERT(tp->t_inpcb);
- if (cur == NULL)
- return; /* No holes */
- if (SEQ_GEQ(tp->snd_nxt, tp->snd_fack))
- return; /* We're already beyond any SACKed blocks */
- /*-
- * Two cases for which we want to advance snd_nxt:
- * i) snd_nxt lies between end of one hole and beginning of another
- * ii) snd_nxt lies between end of last hole and snd_fack
- */
- while ((p = TAILQ_NEXT(cur, scblink)) != NULL) {
- if (SEQ_LT(tp->snd_nxt, cur->end))
- return;
- if (SEQ_GEQ(tp->snd_nxt, p->start))
- cur = p;
- else {
- tp->snd_nxt = p->start;
- return;
- }
- }
- if (SEQ_LT(tp->snd_nxt, cur->end))
- return;
- tp->snd_nxt = tp->snd_fack;
- return;
-}
+#endif
==== //depot/projects/tcp_new/netinet/tcp_subr.c#6 (text+ko) ====
@@ -161,8 +161,6 @@
SYSCTL_INT(_net_inet_tcp, OID_AUTO, isn_reseed_interval, CTLFLAG_RW,
&tcp_isn_reseed_interval, 0, "Seconds between reseeding of ISN secret");
-uma_zone_t sack_hole_zone;
-
static struct inpcb *tcp_notify(struct inpcb *, int);
static void tcp_isn_tick(void *);
@@ -270,13 +268,12 @@
syncache_init();
tcp_hc_init();
tcp_reass_init();
+ tcp_sack_init();
ISN_LOCK_INIT();
callout_init(&isn_callout, CALLOUT_MPSAFE);
tcp_isn_tick(NULL);
EVENTHANDLER_REGISTER(shutdown_pre_sync, tcp_fini, NULL,
SHUTDOWN_PRI_DEFAULT);
- sack_hole_zone = uma_zcreate("sackhole", sizeof(struct sackhole),
- NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
EVENTHANDLER_REGISTER(maxsockets_change, tcp_zone_change, NULL,
EVENTHANDLER_PRI_ANY);
}
@@ -722,7 +719,7 @@
/* Disconnect offload device, if any. */
tcp_offload_detach(tp);
- tcp_free_sackholes(tp);
+ tcp_sack_flush(tp);
inp->inp_ppcb = NULL;
tp->t_inpcb = NULL;
uma_zfree(tcpcb_zone, tp);
@@ -794,7 +791,7 @@
tcpb->t_segqlen--;
tcp_reass_qsize--;
}
- tcp_clean_sackreport(tcpb);
+ tcp_sack_flush(tcpb);
}
INP_UNLOCK(inpb);
}
@@ -1530,7 +1527,7 @@
tcpstat.tcps_mturesent++;
//tp->t_rtttime = 0;
tp->snd_nxt = tp->snd_una;
- tcp_free_sackholes(tp);
+ tcp_sack_flush(tp);
tp->snd_recover = tp->snd_nxt;
//if (tp->t_flags & TF_SACK_PERMIT)
// EXIT_FASTRECOVERY(tp);
==== //depot/projects/tcp_new/netinet/tcp_var.h#11 (text+ko) ====
@@ -96,15 +96,13 @@
extern struct uma_zone *tcp_reass_zone;
struct sackblk {
- tcp_seq start; /* start seq no. of sack block */
- tcp_seq end; /* end seq no. */
+ tcp_seq start; /* left */
+ tcp_seq end; /* right */
};
-struct sackhole {
- tcp_seq start; /* start seq no. of hole */
- tcp_seq end; /* end seq no. */
- tcp_seq rxmit; /* next seq. no in hole to be retransmitted */
- TAILQ_ENTRY(sackhole) scblink; /* scoreboard linkage */
+struct tcp_sack_block {
+ RB_ENTRY(tcp_sackblocks) tsb_rb; /* scoreboard linkage */
+ struct sackblk tsb_blk;
};
struct sackhint {
@@ -252,15 +250,8 @@
#define TCPOOB_HADDATA 0x02
/* SACK related state */
+ RB_HEAD(tcp_sackblocks, tcp_sack_block) snd_sackblocks;
int snd_numholes; /* number of holes seen by sender */
- TAILQ_HEAD(sackhole_head, sackhole) snd_holes;
- /* SACK scoreboard (sorted) */
- tcp_seq snd_fack; /* last seq number(+1) sack'd by rcv'r */
- int rcv_numsacks; /* XXXAO */
- struct sackblk sackblks[MAX_SACK_BLKS]; /* seq nos. of sack blocks */
- tcp_seq sack_newdata; /* New data xmitted in this recovery
- episode starts at this seq number */
- struct sackhint sackhint; /* SACK scoreboard hint */
int snd_sacked; /* data currently ack'ed through SACK */
/* Congestion control algorithms */
@@ -651,12 +642,9 @@
tcp_seq tcp_new_isn(struct tcpcb *);
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_sackreport(struct tcpcb *tp);
-void tcp_sack_adjust(struct tcpcb *tp);
-struct sackhole *tcp_sack_output(struct tcpcb *tp, int *sack_bytes_rexmt);
-void tcp_sack_partialack(struct tcpcb *, struct tcphdr *);
-void tcp_free_sackholes(struct tcpcb *tp);
+void tcp_sack_flush(struct tcpcb *tp);
+void tcp_sack_init(void);
+
int tcp_newreno(struct tcpcb *, struct tcphdr *);
u_long tcp_seq_subtract(u_long, u_long );
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