/*
- * Copyright (c) 2004,2007 Apple Inc. All rights reserved.
+ * Copyright (c) 2004-2016 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_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
* 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,
* 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_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
#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");
+static int tcp_detect_reordering = 1;
+static int tcp_dsack_ignore_hw_duplicates = 0;
+
+#if (DEVELOPMENT || DEBUG)
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, detect_reordering,
+ CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_detect_reordering, 0, "");
+
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, ignore_hw_duplicates,
+ CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_dsack_ignore_hw_duplicates, 0, "");
+#endif /* (DEVELOPMENT || DEBUG) */
+
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.
/* 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 TRAFFIC_MGT
+ if (tp->acc_iaj > 0 && tp->rcv_numsacks > 0)
+ reset_acc_iaj(tp);
+#endif /* TRAFFIC_MGT */
}
/*
return NULL;
}
- hole = (struct sackhole *)zalloc_noblock(sack_hole_zone);
+ hole = (struct sackhole *)zalloc(sack_hole_zone);
if (hole == NULL)
return NULL;
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);
}
/*
hole = tcp_sackhole_alloc(tp, start, end);
if (hole == NULL)
return NULL;
-
+ hole->rxmit_start = tcp_now;
/* Insert the new SACK hole into scoreboard */
if (after != NULL)
TAILQ_INSERT_AFTER(&tp->snd_holes, after, hole, scblink);
if (tp->sackhint.nexthole == NULL)
tp->sackhint.nexthole = hole;
- return hole;
+ return(hole);
}
/*
/* 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.
+ */
+ if (SEQ_LT(s->rxmit, sacked_seq)) {
+ reordered = 1;
+ tcpstat.tcps_avoid_rxmt++;
+ }
+
+ if (reordered) {
+ if (tcp_detect_reordering == 1 &&
+ !(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);
+ }
+ }
+}
/*
* 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)
{
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));
- 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_max) &&
- SEQ_GT(sack.end, tp->snd_una) &&
- SEQ_LEQ(sack.end, tp->snd_max))
- sack_blocks[num_sack_blks++] = 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 (TCP_VALIDATE_SACK_SEQ_NUMBERS(tp, &sack, th_ack))
+ sack_blocks[num_sack_blks++] = sack;
}
/*
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);
+ *newbytes_acked += (tp->snd_fack - tp->snd_una);
+ }
+
+ 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
temp = tcp_sackhole_insert(tp, tp->snd_fack,sblkp->start,NULL);
if (temp != NULL) {
tp->snd_fack = sblkp->end;
+ *newbytes_acked += (sblkp->end - sblkp->start);
+
/* Go to the previous sack block. */
sblkp--;
} else {
SEQ_LT(tp->snd_fack, sblkp->start))
sblkp--;
if (sblkp >= sack_blocks &&
- SEQ_LT(tp->snd_fack, sblkp->end))
+ SEQ_LT(tp->snd_fack, sblkp->end)) {
+ *newbytes_acked += (sblkp->end - tp->snd_fack);
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. */
+ *newbytes_acked += (sblkp->end - tp->snd_fack);
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 */
/*
/* Data acks at least the beginning of hole */
if (SEQ_GEQ(sblkp->end, cur->end)) {
/* Acks entire hole, so delete hole */
+ *newbytes_acked += (cur->end - cur->start);
+
+ 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 */
+ *newbytes_acked += (sblkp->end - cur->start);
+ 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 */
+ *newbytes_acked += (cur->end - sblkp->start);
+ 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
*/
+ *newbytes_acked += (sblkp->end - sblkp->start);
+ 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) {
if (SEQ_GT(cur->rxmit, temp->rxmit)) {
temp->rxmit = cur->rxmit;
cur->end = sblkp->start;
cur->rxmit = SEQ_MIN(cur->rxmit,
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;
}
}
}
* 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)
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);
}
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++;
+
+ /* ignore DSACK option, if DSACK is disabled */
+ if (tp->t_flagsext & TF_DISABLE_DSACK)
+ return (TRUE);
+
+ /* 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 if ((rxseg = tcp_rxtseg_find(tp, first_sack.start,
+ (first_sack.end - 1))) == NULL) {
+ /*
+ * Duplicate notification was not triggered by a
+ * retransmission. This might be due to network duplication,
+ * disable further DSACK processing.
+ */
+ if (!tcp_dsack_ignore_hw_duplicates) {
+ tp->t_flagsext |= TF_DISABLE_DSACK;
+ tcpstat.tcps_dsack_disable++;
+ }
+ } else {
+ /*
+ * If the segment was retransmitted only once, mark it as
+ * spurious. Otherwise ignore the duplicate notification.
+ */
+ if (rxseg->rx_count == 1)
+ rxseg->rx_flags |= TCP_RXT_SPURIOUS;
+ else
+ rxseg->rx_flags &= ~TCP_RXT_SPURIOUS;
+ }
+ return (TRUE);
+}
projects / apple / xnu.git / blobdiff