--- /dev/null
+/*
+ * Copyright (c) 2006 Apple Computer, 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.
+ *
+ * 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@
+ */
+/*
+ * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
+ * The Regents of the University of California. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * 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.
+ * 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 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 THE REGENTS 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.
+ *
+ */
+
+#define _IP_VHL
+
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/sysctl.h>
+#include <sys/mbuf.h>
+#include <sys/domain.h>
+#include <sys/protosw.h>
+#include <sys/socket.h>
+#include <sys/socketvar.h>
+
+#include <net/route.h>
+
+#include <netinet/in.h>
+#include <netinet/in_systm.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>
+#if TCPDEBUG
+#include <netinet/tcp_debug.h>
+#endif
+#include <sys/kdebug.h>
+
+#if IPSEC
+#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,
+ "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,
+ "Global maximum number of TCP SACK holes");
+
+static int tcp_sack_globalholes = 0;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, sack_globalholes, CTLFLAG_RD,
+ &tcp_sack_globalholes, 0,
+ "Global number of TCP SACK holes currently allocated");
+
+extern struct zone *sack_hole_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)
+{
+ /*
+ * 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;
+
+ /* 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;
+}
+
+/*
+ * Delete all receiver-side SACK information.
+ */
+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);
+}
+
+/*
+ * 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 *)zalloc_noblock(sack_hole_zone);
+ if (hole == NULL)
+ return NULL;
+
+ hole->start = start;
+ hole->end = end;
+ hole->rxmit = start;
+
+ tp->snd_numholes++;
+ tcp_sack_globalholes++;
+
+ return hole;
+}
+
+/*
+ * Free struct sackhole.
+ */
+static void
+tcp_sackhole_free(struct tcpcb *tp, struct sackhole *hole)
+{
+ zfree(sack_hole_zone, hole);
+
+ tp->snd_numholes--;
+ tcp_sack_globalholes--;
+}
+
+/*
+ * Insert new SACK hole into scoreboard.
+ */
+static struct sackhole *
+tcp_sackhole_insert(struct tcpcb *tp, tcp_seq start, tcp_seq end,
+ struct sackhole *after)
+{
+ struct sackhole *hole;
+
+ /* 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;
+}
+
+/*
+ * Remove SACK hole from scoreboard.
+ */
+static void
+tcp_sackhole_remove(struct tcpcb *tp, struct sackhole *hole)
+{
+ /* 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).
+ */
+void
+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;
+
+ 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[].
+ */
+ 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_LEQ(sack.end, tp->snd_max))
+ 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)
+ return;
+
+ /*
+ * 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 */
+ 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--;
+ 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);
+ continue;
+ }
+ tp->sackhint.sack_bytes_rexmit -= (cur->rxmit - cur->start);
+ 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.
+ */
+ continue;
+ } else {
+ /* Move start of hole forward */
+ cur->start = sblkp->end;
+ cur->rxmit = SEQ_MAX(cur->rxmit, cur->start);
+ }
+ } 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);
+ }
+ }
+ }
+ 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--;
+ }
+}
+
+/*
+ * Free all SACK holes to clear the scoreboard.
+ */
+void
+tcp_free_sackholes(struct tcpcb *tp)
+{
+ struct sackhole *q;
+
+ while ((q = TAILQ_FIRST(&tp->snd_holes)) != NULL)
+ tcp_sackhole_remove(tp, q);
+ tp->sackhint.sack_bytes_rexmit = 0;
+
+}
+
+/*
+ * 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(tp, th)
+ 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)
+ 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)
+ tp->snd_cwnd = tp->snd_ssthresh;
+ tp->t_flags |= TF_ACKNOW;
+ (void) tcp_output(tp);
+}
+
+/*
+ * 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;
+
+ *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);
+ }
+ return (p);
+}
+
+/*
+ * 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)
+{
+ struct sackhole *hole = NULL, *dbg_hole = NULL;
+ int dbg_bytes_rexmt;
+
+ 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))
+ goto out;
+ while ((hole = TAILQ_NEXT(hole, scblink)) != NULL) {
+ if (SEQ_LT(hole->rxmit, hole->end)) {
+ tp->sackhint.nexthole = hole;
+ break;
+ }
+ }
+out:
+ if (dbg_hole != hole) {
+ printf("%s: Computed sack hole not the same as cached value\n", __func__);
+ hole = dbg_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);
+ *sack_bytes_rexmt = dbg_bytes_rexmt;
+ }
+ 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);
+
+ 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;
+}
projects / apple / xnu.git / blobdiff