/*
- * Copyright (c) 2004 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2004-2016 Apple Inc. All rights reserved.
*
- * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
- *
- * This file contains Original Code and/or Modifications of Original Code
- * as defined in and that are subject to the Apple Public Source License
- * Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. The rights granted to you under the
- * License may not be used to create, or enable the creation or
- * redistribution of, unlawful or unlicensed copies of an Apple operating
- * system, or to circumvent, violate, or enable the circumvention or
- * violation of, any terms of an Apple operating system software license
- * agreement.
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
- * Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
*
- * The Original Code and all software distributed under the License are
- * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
- * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
- * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
- * Please see the License for the specific language governing rights and
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
* limitations under the License.
*
- * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
* modification, are permitted 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.
+ * 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.
+ * 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 acknowledgement:
+ * must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
*
*/
-#define _IP_VHL
+#define _IP_VHL
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
+#include <kern/zalloc.h>
+
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/ip_var.h>
-#if INET6
#include <netinet6/in6_pcb.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
-#endif
#include <netinet/tcp.h>
-//#define TCPOUTFLAGS
#include <netinet/tcp_fsm.h>
#include <netinet/tcp_seq.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <netinet/tcpip.h>
+#include <netinet/tcp_cache.h>
#if TCPDEBUG
#include <netinet/tcp_debug.h>
#endif
#include <netinet6/ipsec.h>
#endif /*IPSEC*/
-int tcp_do_sack = 1;
-SYSCTL_INT(_net_inet_tcp, OID_AUTO, sack, CTLFLAG_RW, &tcp_do_sack, 0,
- "Enable/Disable TCP SACK support");
-static int tcp_sack_maxholes = 128;
-SYSCTL_INT(_net_inet_tcp, OID_AUTO, sack_maxholes, CTLFLAG_RW,
- &tcp_sack_maxholes, 0,
+#include <libkern/OSAtomic.h>
+
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, sack, CTLFLAG_RW | CTLFLAG_LOCKED,
+ int, tcp_do_sack, 1, "Enable/Disable TCP SACK support");
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, sack_maxholes, CTLFLAG_RW | CTLFLAG_LOCKED,
+ static int, tcp_sack_maxholes, 128,
"Maximum number of TCP SACK holes allowed per connection");
-static int tcp_sack_globalmaxholes = 65536;
-SYSCTL_INT(_net_inet_tcp, OID_AUTO, sack_globalmaxholes, CTLFLAG_RW,
- &tcp_sack_globalmaxholes, 0,
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, sack_globalmaxholes,
+ CTLFLAG_RW | CTLFLAG_LOCKED, static int, tcp_sack_globalmaxholes, 65536,
"Global maximum number of TCP SACK holes");
-static int tcp_sack_globalholes = 0;
-SYSCTL_INT(_net_inet_tcp, OID_AUTO, sack_globalholes, CTLFLAG_RD,
+static SInt32 tcp_sack_globalholes = 0;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, sack_globalholes, CTLFLAG_RD | CTLFLAG_LOCKED,
&tcp_sack_globalholes, 0,
"Global number of TCP SACK holes currently allocated");
extern struct zone *sack_hole_zone;
+#define TCP_VALIDATE_SACK_SEQ_NUMBERS(_tp_, _sb_, _ack_) \
+ (SEQ_GT((_sb_)->end, (_sb_)->start) && \
+ SEQ_GT((_sb_)->start, (_tp_)->snd_una) && \
+ SEQ_GT((_sb_)->start, (_ack_)) && \
+ SEQ_LT((_sb_)->start, (_tp_)->snd_max) && \
+ SEQ_GT((_sb_)->end, (_tp_)->snd_una) && \
+ SEQ_LEQ((_sb_)->end, (_tp_)->snd_max))
+
/*
* This function is called upon receipt of new valid data (while not in header
* prediction mode), and it updates the ordered list of sacks.
* Discard this SACK block.
*/
} else if (SEQ_LEQ(head_blk.start, end) &&
- SEQ_GEQ(head_blk.end, start)) {
+ 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))
+ if (SEQ_GT(head_blk.start, start)) {
head_blk.start = start;
- if (SEQ_LT(head_blk.end, end))
+ }
+ if (SEQ_LT(head_blk.end, end)) {
head_blk.end = end;
+ }
} else {
/*
* Save this SACK block.
* If the number of saved SACK blocks exceeds its limit,
* discard the last SACK block.
*/
- if (num_saved >= MAX_SACK_BLKS)
+ 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);
+ 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;
+
+ /* If we are requesting SACK recovery, reset the stretch-ack state
+ * so that connection will generate more acks after recovery and
+ * sender's cwnd will open.
+ */
+ if ((tp->t_flags & TF_STRETCHACK) != 0 && tp->rcv_numsacks > 0) {
+ tcp_reset_stretch_ack(tp);
+ }
+ if (tp->rcv_numsacks > 0) {
+ tp->t_forced_acks = TCP_FORCED_ACKS_COUNT;
+ }
+
+#if TRAFFIC_MGT
+ if (tp->acc_iaj > 0 && tp->rcv_numsacks > 0) {
+ reset_acc_iaj(tp);
+ }
+#endif /* TRAFFIC_MGT */
}
/*
void
tcp_clean_sackreport( struct tcpcb *tp)
{
-/*
- int i;
-
tp->rcv_numsacks = 0;
- for (i = 0; i < MAX_SACK_BLKS; i++)
- tp->sackblks[i].start = tp->sackblks[i].end=0;
-*/
- bzero(&tp->sackblks[0], sizeof (struct sackblk) * MAX_SACK_BLKS);
+ bzero(&tp->sackblks[0], sizeof(struct sackblk) * MAX_SACK_BLKS);
}
/*
return NULL;
}
- hole = (struct sackhole *)zalloc_noblock(sack_hole_zone);
- if (hole == NULL)
+ hole = (struct sackhole *)zalloc(sack_hole_zone);
+ if (hole == NULL) {
return NULL;
+ }
hole->start = start;
hole->end = end;
hole->rxmit = start;
tp->snd_numholes++;
- tcp_sack_globalholes++;
+ OSIncrementAtomic(&tcp_sack_globalholes);
return hole;
}
zfree(sack_hole_zone, hole);
tp->snd_numholes--;
- tcp_sack_globalholes--;
+ OSDecrementAtomic(&tcp_sack_globalholes);
}
/*
*/
static struct sackhole *
tcp_sackhole_insert(struct tcpcb *tp, tcp_seq start, tcp_seq end,
- struct sackhole *after)
+ struct sackhole *after)
{
struct sackhole *hole;
/* Allocate a new SACK hole. */
hole = tcp_sackhole_alloc(tp, start, end);
- if (hole == NULL)
+ if (hole == NULL) {
return NULL;
-
+ }
+ hole->rxmit_start = tcp_now;
/* Insert the new SACK hole into scoreboard */
- if (after != NULL)
+ if (after != NULL) {
TAILQ_INSERT_AFTER(&tp->snd_holes, after, hole, scblink);
- else
+ } else {
TAILQ_INSERT_TAIL(&tp->snd_holes, hole, scblink);
+ }
/* Update SACK hint. */
- if (tp->sackhint.nexthole == NULL)
+ if (tp->sackhint.nexthole == NULL) {
tp->sackhint.nexthole = hole;
+ }
return hole;
}
tcp_sackhole_remove(struct tcpcb *tp, struct sackhole *hole)
{
/* Update SACK hint. */
- if (tp->sackhint.nexthole == hole)
+ 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);
}
+/*
+ * When a new ack with SACK is received, check if it indicates packet
+ * reordering. If there is packet reordering, the socket is marked and
+ * the late time offset by which the packet was reordered with
+ * respect to its closest neighboring packets is computed.
+ */
+static void
+tcp_sack_detect_reordering(struct tcpcb *tp, struct sackhole *s,
+ tcp_seq sacked_seq, tcp_seq snd_fack)
+{
+ int32_t rext = 0, reordered = 0;
+
+ /*
+ * If the SACK hole is past snd_fack, this is from new SACK
+ * information, so we can ignore it.
+ */
+ if (SEQ_GT(s->end, snd_fack)) {
+ return;
+ }
+ /*
+ * If there has been a retransmit timeout, then the timestamp on
+ * the SACK segment will be newer. This might lead to a
+ * false-positive. Avoid re-ordering detection in this case.
+ */
+ if (tp->t_rxtshift > 0) {
+ return;
+ }
+
+ /*
+ * Detect reordering from SACK information by checking
+ * if recently sacked data was never retransmitted from this hole.
+ *
+ * First, we look for the byte in the list of retransmitted segments. This one
+ * will contain even the segments that are retransmitted thanks to RTO/TLP.
+ *
+ * Then, we check the sackhole which indicates whether or not the sackhole
+ * was subject to retransmission.
+ */
+ if (SEQ_LT(s->rxmit, sacked_seq) &&
+ (!tcp_do_better_lr || tcp_rxtseg_find(tp, sacked_seq - 1, sacked_seq - 1) == NULL)) {
+ reordered = 1;
+ tcpstat.tcps_avoid_rxmt++;
+ }
+
+ if (reordered) {
+ if (!(tp->t_flagsext & TF_PKTS_REORDERED)) {
+ tp->t_flagsext |= TF_PKTS_REORDERED;
+ tcpstat.tcps_detect_reordering++;
+ }
+
+ tcpstat.tcps_reordered_pkts++;
+ tp->t_reordered_pkts++;
+
+ /*
+ * If reordering is seen on a connection wth ECN enabled,
+ * increment the heuristic
+ */
+ if (TCP_ECN_ENABLED(tp)) {
+ INP_INC_IFNET_STAT(tp->t_inpcb, ecn_fallback_reorder);
+ tcpstat.tcps_ecn_fallback_reorder++;
+ tcp_heuristic_ecn_aggressive(tp);
+ }
+
+ VERIFY(SEQ_GEQ(snd_fack, s->rxmit));
+
+ if (s->rxmit_start > 0) {
+ rext = timer_diff(tcp_now, 0, s->rxmit_start, 0);
+ if (rext < 0) {
+ return;
+ }
+
+ /*
+ * We take the maximum reorder window to schedule
+ * DELAYFR timer as that will take care of jitter
+ * on the network path.
+ *
+ * Computing average and standard deviation seems
+ * to cause unnecessary retransmissions when there
+ * is high jitter.
+ *
+ * We set a maximum of SRTT/2 and a minimum of
+ * 10 ms on the reorder window.
+ */
+ tp->t_reorderwin = max(tp->t_reorderwin, rext);
+ tp->t_reorderwin = min(tp->t_reorderwin,
+ (tp->t_srtt >> (TCP_RTT_SHIFT - 1)));
+ tp->t_reorderwin = max(tp->t_reorderwin, 10);
+ }
+ }
+}
+
+static void
+tcp_sack_update_byte_counter(struct tcpcb *tp, uint32_t start, uint32_t end,
+ uint32_t *newbytes_acked, uint32_t *towards_fr_acked)
+{
+ *newbytes_acked += (end - start);
+ if (SEQ_GEQ(start, tp->send_highest_sack)) {
+ *towards_fr_acked += (end - start);
+ }
+}
/*
* Process cumulative ACK and the TCP SACK option to update the scoreboard.
* the sequence space).
*/
void
-tcp_sack_doack(struct tcpcb *tp, struct tcpopt *to, tcp_seq th_ack)
+tcp_sack_doack(struct tcpcb *tp, struct tcpopt *to, struct tcphdr *th,
+ u_int32_t *newbytes_acked, uint32_t *after_rexmit_acked)
{
struct sackhole *cur, *temp;
struct sackblk sack, sack_blocks[TCP_MAX_SACK + 1], *sblkp;
int i, j, num_sack_blks;
+ tcp_seq old_snd_fack = 0, th_ack = th->th_ack;
num_sack_blks = 0;
/*
}
/*
* Append received valid SACK blocks to sack_blocks[].
+ * Check that the SACK block range is valid.
*/
for (i = 0; i < to->to_nsacks; i++) {
- bcopy((to->to_sacks + i * TCPOLEN_SACK), &sack, sizeof(sack));
+ 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_LEQ(sack.end, tp->snd_max))
+ if (TCP_VALIDATE_SACK_SEQ_NUMBERS(tp, &sack, th_ack)) {
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 (num_sack_blks == 0) {
return;
+ }
+ VERIFY(num_sack_blks <= (TCP_MAX_SACK + 1));
/*
* Sort the SACK blocks so we can update the scoreboard
* with just one pass. The overhead of sorting upto 4+1 elements
}
}
}
- if (TAILQ_EMPTY(&tp->snd_holes))
+ if (TAILQ_EMPTY(&tp->snd_holes)) {
/*
* Empty scoreboard. Need to initialize snd_fack (it may be
* uninitialized or have a bogus value). Scoreboard holes
* the logic that adds holes to the tail of the scoreboard).
*/
tp->snd_fack = SEQ_MAX(tp->snd_una, th_ack);
+ }
+
+ old_snd_fack = tp->snd_fack;
/*
* In the while-loop below, incoming SACK blocks (sack_blocks[])
* and SACK holes (snd_holes) are traversed from their tails with
* the highest three or four SACK blocks with ack number advancing
* are received.
*/
- sblkp = &sack_blocks[num_sack_blks - 1]; /* Last SACK block */
+ 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.
* 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);
+ temp = tcp_sackhole_insert(tp, tp->snd_fack, sblkp->start, NULL);
if (temp != NULL) {
tp->snd_fack = sblkp->end;
+ tcp_sack_update_byte_counter(tp, sblkp->start, sblkp->end, newbytes_acked, after_rexmit_acked);
+
/* 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
+ /*
+ * 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
+ * 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))
+ while (sblkp >= sack_blocks &&
+ SEQ_LT(tp->snd_fack, sblkp->start)) {
sblkp--;
- if (sblkp >= sack_blocks &&
- SEQ_LT(tp->snd_fack, sblkp->end))
+ }
+ if (sblkp >= sack_blocks &&
+ SEQ_LT(tp->snd_fack, sblkp->end)) {
+ tcp_sack_update_byte_counter(tp, tp->snd_fack, sblkp->end, newbytes_acked, after_rexmit_acked);
tp->snd_fack = sblkp->end;
+ }
}
- } else if (SEQ_LT(tp->snd_fack, sblkp->end))
+ } else if (SEQ_LT(tp->snd_fack, sblkp->end)) {
/* fack is advanced. */
+ tcp_sack_update_byte_counter(tp, tp->snd_fack, sblkp->end, newbytes_acked, after_rexmit_acked);
tp->snd_fack = sblkp->end;
+ }
/* We must have at least one SACK hole in scoreboard */
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) {
+ while (sblkp >= sack_blocks && cur != NULL) {
if (SEQ_GEQ(sblkp->start, cur->end)) {
/*
* SACKs data beyond the current hole.
continue;
}
tp->sackhint.sack_bytes_rexmit -= (cur->rxmit - cur->start);
+ if (tp->sackhint.sack_bytes_rexmit < 0) {
+ tp->sackhint.sack_bytes_rexmit = 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 */
+ tcp_sack_update_byte_counter(tp, cur->start, cur->end, newbytes_acked, after_rexmit_acked);
+
+ tcp_sack_detect_reordering(tp, cur,
+ cur->end, old_snd_fack);
temp = cur;
cur = TAILQ_PREV(cur, sackhole_head, scblink);
tcp_sackhole_remove(tp, temp);
continue;
} else {
/* Move start of hole forward */
+ tcp_sack_update_byte_counter(tp, cur->start, sblkp->end, newbytes_acked, after_rexmit_acked);
+ tcp_sack_detect_reordering(tp, cur,
+ sblkp->end, old_snd_fack);
cur->start = sblkp->end;
cur->rxmit = SEQ_MAX(cur->rxmit, cur->start);
}
/* Data acks at least the end of hole */
if (SEQ_GEQ(sblkp->end, cur->end)) {
/* Move end of hole backward */
+ tcp_sack_update_byte_counter(tp, sblkp->start, cur->end, newbytes_acked, after_rexmit_acked);
+ tcp_sack_detect_reordering(tp, cur,
+ cur->end, old_snd_fack);
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
+ * ACKs some data in the middle of a hole;
+ * need to split current hole
*/
+ tcp_sack_detect_reordering(tp, cur,
+ sblkp->end, old_snd_fack);
temp = tcp_sackhole_insert(tp, sblkp->end,
- cur->end, cur);
+ cur->end, cur);
if (temp != NULL) {
+ tcp_sack_update_byte_counter(tp, sblkp->start, sblkp->end, newbytes_acked, after_rexmit_acked);
if (SEQ_GT(cur->rxmit, temp->rxmit)) {
temp->rxmit = cur->rxmit;
tp->sackhint.sack_bytes_rexmit
- += (temp->rxmit
- - temp->start);
+ += (temp->rxmit
+ - temp->start);
}
cur->end = sblkp->start;
cur->rxmit = SEQ_MIN(cur->rxmit,
- cur->end);
+ cur->end);
+ /*
+ * Reset the rxmit_start to that of
+ * the current hole as that will
+ * help to compute the reorder
+ * window correctly
+ */
+ temp->rxmit_start = cur->rxmit_start;
}
}
}
* 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))
+ if (SEQ_LEQ(sblkp->start, cur->start)) {
cur = TAILQ_PREV(cur, sackhole_head, scblink);
- else
+ } else {
sblkp--;
+ }
}
}
{
struct sackhole *q;
- while ((q = TAILQ_FIRST(&tp->snd_holes)) != NULL)
+ while ((q = TAILQ_FIRST(&tp->snd_holes)) != NULL) {
tcp_sackhole_remove(tp, q);
+ }
tp->sackhint.sack_bytes_rexmit = 0;
-
+ tp->sackhint.sack_bytes_acked = 0;
+ tp->t_new_dupacks = 0;
+ tp->sackhint.nexthole = NULL;
+ tp->sack_newdata = 0;
}
/*
- * Partial ack handling within a sack recovery episode.
+ * 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
+ * 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(tp, th)
- struct tcpcb *tp;
- struct tcphdr *th;
+tcp_sack_partialack(struct tcpcb *tp, struct tcphdr *th)
{
int num_segs = 1;
tp->t_timer[TCPT_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->t_maxseg) > 2)
+ if (((BYTES_ACKED(th, tp)) / tp->t_maxseg) > 2) {
num_segs = 2;
- tp->snd_cwnd = (tp->sackhint.sack_bytes_rexmit +
- (tp->snd_nxt - tp->sack_newdata) +
- num_segs * tp->t_maxseg);
- if (tp->snd_cwnd > tp->snd_ssthresh)
+ }
+ if (tcp_do_better_lr) {
+ tp->snd_cwnd = tcp_flight_size(tp) + num_segs * tp->t_maxseg;
+ } else {
+ tp->snd_cwnd = (tp->sackhint.sack_bytes_rexmit +
+ (tp->snd_nxt - tp->sack_newdata) +
+ num_segs * tp->t_maxseg);
+ }
+ if (tp->snd_cwnd > tp->snd_ssthresh) {
tp->snd_cwnd = tp->snd_ssthresh;
- tp->t_flags |= TF_ACKNOW;
+ }
+ if (SEQ_LT(tp->snd_fack, tp->snd_recover) &&
+ tp->snd_fack == th->th_ack && TAILQ_EMPTY(&tp->snd_holes)) {
+ struct sackhole *temp;
+ /*
+ * we received a partial ack but there is no sack_hole
+ * that will cover the remaining seq space. In this case,
+ * create a hole from snd_fack to snd_recover so that
+ * the sack recovery will continue.
+ */
+ temp = tcp_sackhole_insert(tp, tp->snd_fack,
+ tp->snd_recover, NULL);
+ if (temp != NULL) {
+ tp->snd_fack = tp->snd_recover;
+ }
+ }
(void) tcp_output(tp);
}
}
*sack_bytes_rexmt += (p->rxmit - p->start);
}
- return (p);
+ return p;
}
/*
dbg_hole = tcp_sack_output_debug(tp, &dbg_bytes_rexmt);
*sack_bytes_rexmt = tp->sackhint.sack_bytes_rexmit;
hole = tp->sackhint.nexthole;
- if (hole == NULL || SEQ_LT(hole->rxmit, hole->end))
+ 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;
}
if (*sack_bytes_rexmt != dbg_bytes_rexmt) {
printf("%s: Computed sack_bytes_retransmitted (%d) not "
- "the same as cached value (%d)\n",
- __func__, dbg_bytes_rexmt, *sack_bytes_rexmt);
+ "the same as cached value (%d)\n",
+ __func__, dbg_bytes_rexmt, *sack_bytes_rexmt);
*sack_bytes_rexmt = dbg_bytes_rexmt;
}
- return (hole);
+ return hole;
+}
+
+void
+tcp_sack_lost_rexmit(struct tcpcb *tp)
+{
+ struct sackhole *hole = TAILQ_FIRST(&tp->snd_holes);
+
+ while (hole) {
+ hole->rxmit = hole->start;
+ hole->rxmit_start = tcp_now;
+
+ hole = TAILQ_NEXT(hole, scblink);
+ }
+
+ tp->sackhint.nexthole = TAILQ_FIRST(&tp->snd_holes);
+ tp->sackhint.sack_bytes_rexmit = 0;
+ tp->sack_newdata = tp->snd_nxt;
}
/*
{
struct sackhole *p, *cur = TAILQ_FIRST(&tp->snd_holes);
- if (cur == NULL)
+ if (cur == NULL) {
return; /* No holes */
- if (SEQ_GEQ(tp->snd_nxt, tp->snd_fack))
+ }
+ 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))
+ if (SEQ_LT(tp->snd_nxt, cur->end)) {
return;
- if (SEQ_GEQ(tp->snd_nxt, p->start))
+ }
+ if (SEQ_GEQ(tp->snd_nxt, p->start)) {
cur = p;
- else {
+ } else {
tp->snd_nxt = p->start;
return;
}
}
- if (SEQ_LT(tp->snd_nxt, cur->end))
+ if (SEQ_LT(tp->snd_nxt, cur->end)) {
return;
+ }
tp->snd_nxt = tp->snd_fack;
return;
}
+
+/*
+ * This function returns TRUE if more than (tcprexmtthresh - 1) * SMSS
+ * bytes with sequence numbers greater than snd_una have been SACKed.
+ */
+boolean_t
+tcp_sack_byte_islost(struct tcpcb *tp)
+{
+ u_int32_t unacked_bytes, sndhole_bytes = 0;
+ struct sackhole *sndhole;
+ if (!SACK_ENABLED(tp) || IN_FASTRECOVERY(tp) ||
+ TAILQ_EMPTY(&tp->snd_holes) ||
+ (tp->t_flagsext & TF_PKTS_REORDERED)) {
+ return FALSE;
+ }
+
+ unacked_bytes = tp->snd_max - tp->snd_una;
+
+ TAILQ_FOREACH(sndhole, &tp->snd_holes, scblink) {
+ sndhole_bytes += (sndhole->end - sndhole->start);
+ }
+
+ VERIFY(unacked_bytes >= sndhole_bytes);
+ return (unacked_bytes - sndhole_bytes) >
+ ((tcprexmtthresh - 1) * tp->t_maxseg);
+}
+
+/*
+ * Process any DSACK options that might be present on an input packet
+ */
+
+boolean_t
+tcp_sack_process_dsack(struct tcpcb *tp, struct tcpopt *to,
+ struct tcphdr *th)
+{
+ struct sackblk first_sack, second_sack;
+ struct tcp_rxt_seg *rxseg;
+
+ bcopy(to->to_sacks, &first_sack, sizeof(first_sack));
+ first_sack.start = ntohl(first_sack.start);
+ first_sack.end = ntohl(first_sack.end);
+
+ if (to->to_nsacks > 1) {
+ bcopy((to->to_sacks + TCPOLEN_SACK), &second_sack,
+ sizeof(second_sack));
+ second_sack.start = ntohl(second_sack.start);
+ second_sack.end = ntohl(second_sack.end);
+ }
+
+ if (SEQ_LT(first_sack.start, th->th_ack) &&
+ SEQ_LEQ(first_sack.end, th->th_ack)) {
+ /*
+ * There is a dsack option reporting a duplicate segment
+ * also covered by cumulative acknowledgement.
+ *
+ * Validate the sequence numbers before looking at dsack
+ * option. The duplicate notification can come after
+ * snd_una moves forward. In order to set a window of valid
+ * sequence numbers to look for, we set a maximum send
+ * window within which the DSACK option will be processed.
+ */
+ if (!(TCP_DSACK_SEQ_IN_WINDOW(tp, first_sack.start, th->th_ack) &&
+ TCP_DSACK_SEQ_IN_WINDOW(tp, first_sack.end, th->th_ack))) {
+ to->to_nsacks--;
+ to->to_sacks += TCPOLEN_SACK;
+ tcpstat.tcps_dsack_recvd_old++;
+
+ /*
+ * returning true here so that the ack will not be
+ * treated as duplicate ack.
+ */
+ return TRUE;
+ }
+ } else if (to->to_nsacks > 1 &&
+ SEQ_LEQ(second_sack.start, first_sack.start) &&
+ SEQ_GEQ(second_sack.end, first_sack.end)) {
+ /*
+ * there is a dsack option in the first block not
+ * covered by the cumulative acknowledgement but covered
+ * by the second sack block.
+ *
+ * verify the sequence numbes on the second sack block
+ * before processing the DSACK option. Returning false
+ * here will treat the ack as a duplicate ack.
+ */
+ if (!TCP_VALIDATE_SACK_SEQ_NUMBERS(tp, &second_sack,
+ th->th_ack)) {
+ to->to_nsacks--;
+ to->to_sacks += TCPOLEN_SACK;
+ tcpstat.tcps_dsack_recvd_old++;
+ return TRUE;
+ }
+ } else {
+ /* no dsack options, proceed with processing the sack */
+ return FALSE;
+ }
+
+ /* Update the tcpopt pointer to exclude dsack block */
+ to->to_nsacks--;
+ to->to_sacks += TCPOLEN_SACK;
+ tcpstat.tcps_dsack_recvd++;
+ tp->t_dsack_recvd++;
+
+ /* If the DSACK is for TLP mark it as such */
+ if ((tp->t_flagsext & TF_SENT_TLPROBE) &&
+ first_sack.end == tp->t_tlphighrxt) {
+ if ((rxseg = tcp_rxtseg_find(tp, first_sack.start,
+ (first_sack.end - 1))) != NULL) {
+ rxseg->rx_flags |= TCP_RXT_DSACK_FOR_TLP;
+ }
+ }
+ /* Update the sender's retransmit segment state */
+ if (((tp->t_rxtshift == 1 && first_sack.start == tp->snd_una) ||
+ ((tp->t_flagsext & TF_SENT_TLPROBE) &&
+ first_sack.end == tp->t_tlphighrxt)) &&
+ TAILQ_EMPTY(&tp->snd_holes) &&
+ SEQ_GT(th->th_ack, tp->snd_una)) {
+ /*
+ * If the dsack is for a retransmitted packet and one of
+ * the two cases is true, it indicates ack loss:
+ * - retransmit timeout and first_sack.start == snd_una
+ * - TLP probe and first_sack.end == tlphighrxt
+ *
+ * Ignore dsack and do not update state when there is
+ * ack loss
+ */
+ tcpstat.tcps_dsack_ackloss++;
+
+ return TRUE;
+ } else {
+ tcp_rxtseg_set_spurious(tp, first_sack.start, (first_sack.end - 1));
+ }
+ return TRUE;
+}
projects / apple / xnu.git / blobdiff