/*
- * Copyright (c) 2004 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2004-2014 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
#include <sys/socket.h>
#include <sys/socketvar.h>
+#include <kern/zalloc.h>
+
#include <net/route.h>
#include <netinet/in.h>
#include <netinet6/ipsec.h>
#endif /*IPSEC*/
+#include <libkern/OSAtomic.h>
+
int tcp_do_sack = 1;
-SYSCTL_INT(_net_inet_tcp, OID_AUTO, sack, CTLFLAG_RW, &tcp_do_sack, 0,
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, sack, CTLFLAG_RW | CTLFLAG_LOCKED, &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,
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, sack_maxholes, CTLFLAG_RW | CTLFLAG_LOCKED,
&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,
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, sack_globalmaxholes, CTLFLAG_RW | CTLFLAG_LOCKED,
&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,
+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");
/* 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 */
}
/*
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);
}
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);
/* 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 (!(tp->t_flagsext & TF_PKTS_REORDERED)) {
+ tp->t_flagsext |= TF_PKTS_REORDERED;
+ tcpstat.tcps_detect_reordering++;
+ }
+
+ tcpstat.tcps_reordered_pkts++;
+
+ 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));
+ 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;
}
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;
}
}
}
while ((q = TAILQ_FIRST(&tp->snd_holes)) != NULL)
tcp_sackhole_remove(tp, q);
tp->sackhint.sack_bytes_rexmit = 0;
+ tp->sackhint.nexthole = NULL;
+ tp->sack_newdata = 0;
}
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) +
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));
+}
projects / apple / xnu.git / blobdiff