* Tcp output routine: figure out what should be sent and send it.
*/
int
-tcp_output(tp)
- register struct tcpcb *tp;
+tcp_output(struct tcpcb *tp)
{
- register struct socket *so = tp->t_inpcb->inp_socket;
- register long len, win;
+ struct socket *so = tp->t_inpcb->inp_socket;
+ long len, recwin, sendwin;
int off, flags, error;
register struct mbuf *m;
struct ip *ip = NULL;
u_char opt[TCP_MAXOLEN];
unsigned ipoptlen, optlen, hdrlen;
int idle, sendalot, howmuchsent = 0;
+ int i, sack_rxmit;
+ int sack_bytes_rxmt;
+ struct sackhole *p;
+
int maxburst = TCP_MAXBURST;
struct rmxp_tao *taop;
struct rmxp_tao tao_noncached;
* If there is some data or critical controls (SYN, RST)
* to send, then transmit; otherwise, investigate further.
*/
- idle = (tp->snd_max == tp->snd_una);
+ idle = (tp->t_flags & TF_LASTIDLE) || (tp->snd_max == tp->snd_una);
if (idle && tp->t_rcvtime >= tp->t_rxtcur) {
/*
* We have been idle for "a while" and no acks are
* expected to clock out any data we send --
* slow start to get ack "clock" running again.
- *
+ *
* Set the slow-start flight size depending on whether
* this is a local network or not.
- */
+ */
if (
#if INET6
(isipv6 && in6_localaddr(&tp->t_inpcb->in6p_faddr)) ||
else
tp->snd_cwnd = tp->t_maxseg * ss_fltsz;
}
-
+ tp->t_flags &= ~TF_LASTIDLE;
+ if (idle) {
+ if (tp->t_flags & TF_MORETOCOME) {
+ tp->t_flags |= TF_LASTIDLE;
+ idle = 0;
+ }
+ }
again:
KERNEL_DEBUG(DBG_FNC_TCP_OUTPUT | DBG_FUNC_START, 0,0,0,0,0);
}
}
}
+
+ /*
+ * If we've recently taken a timeout, snd_max will be greater than
+ * snd_nxt. There may be SACK information that allows us to avoid
+ * resending already delivered data. Adjust snd_nxt accordingly.
+ */
+ if (tp->sack_enable && SEQ_LT(tp->snd_nxt, tp->snd_max))
+ tcp_sack_adjust(tp);
sendalot = 0;
off = tp->snd_nxt - tp->snd_una;
- win = min(tp->snd_wnd, tp->snd_cwnd);
+ sendwin = min(tp->snd_wnd, tp->snd_cwnd);
+
if (tp->t_flags & TF_SLOWLINK && slowlink_wsize > 0)
- win = min(win, slowlink_wsize);
+ sendwin = min(sendwin, slowlink_wsize);
flags = tcp_outflags[tp->t_state];
+ /*
+ * Send any SACK-generated retransmissions. If we're explicitly trying
+ * to send out new data (when sendalot is 1), bypass this function.
+ * If we retransmit in fast recovery mode, decrement snd_cwnd, since
+ * we're replacing a (future) new transmission with a retransmission
+ * now, and we previously incremented snd_cwnd in tcp_input().
+ */
+ /*
+ * Still in sack recovery , reset rxmit flag to zero.
+ */
+ sack_rxmit = 0;
+ sack_bytes_rxmt = 0;
+ len = 0;
+ p = NULL;
+ if (tp->sack_enable && IN_FASTRECOVERY(tp) &&
+ (p = tcp_sack_output(tp, &sack_bytes_rxmt))) {
+ long cwin;
+
+ cwin = min(tp->snd_wnd, tp->snd_cwnd) - sack_bytes_rxmt;
+ if (cwin < 0)
+ cwin = 0;
+ /* Do not retransmit SACK segments beyond snd_recover */
+ if (SEQ_GT(p->end, tp->snd_recover)) {
+ /*
+ * (At least) part of sack hole extends beyond
+ * snd_recover. Check to see if we can rexmit data
+ * for this hole.
+ */
+ if (SEQ_GEQ(p->rxmit, tp->snd_recover)) {
+ /*
+ * Can't rexmit any more data for this hole.
+ * That data will be rexmitted in the next
+ * sack recovery episode, when snd_recover
+ * moves past p->rxmit.
+ */
+ p = NULL;
+ goto after_sack_rexmit;
+ } else
+ /* Can rexmit part of the current hole */
+ len = ((long)ulmin(cwin,
+ tp->snd_recover - p->rxmit));
+ } else
+ len = ((long)ulmin(cwin, p->end - p->rxmit));
+ off = p->rxmit - tp->snd_una;
+ if (len > 0) {
+ sack_rxmit = 1;
+ sendalot = 1;
+ tcpstat.tcps_sack_rexmits++;
+ tcpstat.tcps_sack_rexmit_bytes +=
+ min(len, tp->t_maxseg);
+ }
+ }
+after_sack_rexmit:
/*
* Get standard flags, and add SYN or FIN if requested by 'hidden'
* state flags.
* and go to transmit state.
*/
if (tp->t_force) {
- if (win == 0) {
+ if (sendwin == 0) {
/*
* If we still have some data to send, then
* clear the FIN bit. Usually this would
*/
if (off < so->so_snd.sb_cc)
flags &= ~TH_FIN;
- win = 1;
+ sendwin = 1;
} else {
tp->t_timer[TCPT_PERSIST] = 0;
tp->t_rxtshift = 0;
}
}
- len = (long)ulmin(so->so_snd.sb_cc, win) - off;
-
- if ((taop = tcp_gettaocache(tp->t_inpcb)) == NULL) {
- taop = &tao_noncached;
- bzero(taop, sizeof(*taop));
+ /*
+ * If snd_nxt == snd_max and we have transmitted a FIN, the
+ * offset will be > 0 even if so_snd.sb_cc is 0, resulting in
+ * a negative length. This can also occur when TCP opens up
+ * its congestion window while receiving additional duplicate
+ * acks after fast-retransmit because TCP will reset snd_nxt
+ * to snd_max after the fast-retransmit.
+ *
+ * In the normal retransmit-FIN-only case, however, snd_nxt will
+ * be set to snd_una, the offset will be 0, and the length may
+ * wind up 0.
+ *
+ * If sack_rxmit is true we are retransmitting from the scoreboard
+ * in which case len is already set.
+ */
+ if (sack_rxmit == 0) {
+ if (sack_bytes_rxmt == 0)
+ len = ((long)ulmin(so->so_snd.sb_cc, sendwin) - off);
+ else {
+ long cwin;
+
+ /*
+ * We are inside of a SACK recovery episode and are
+ * sending new data, having retransmitted all the
+ * data possible in the scoreboard.
+ */
+ len = ((long)ulmin(so->so_snd.sb_cc, tp->snd_wnd)
+ - off);
+ /*
+ * Don't remove this (len > 0) check !
+ * We explicitly check for len > 0 here (although it
+ * isn't really necessary), to work around a gcc
+ * optimization issue - to force gcc to compute
+ * len above. Without this check, the computation
+ * of len is bungled by the optimizer.
+ */
+ if (len > 0) {
+ cwin = tp->snd_cwnd -
+ (tp->snd_nxt - tp->sack_newdata) -
+ sack_bytes_rxmt;
+ if (cwin < 0)
+ cwin = 0;
+ len = lmin(len, cwin);
+ }
+ }
}
/*
if ((flags & TH_SYN) && SEQ_GT(tp->snd_nxt, tp->snd_una)) {
flags &= ~TH_SYN;
off--, len++;
- if (len > 0 && tp->t_state == TCPS_SYN_SENT &&
- taop->tao_ccsent == 0) {
+ if (len > 0 && tp->t_state == TCPS_SYN_SENT) {
if (packetlist) {
error = ip_output_list(packetlist, packchain_listadd, tp->t_inpcb->inp_options, &tp->t_inpcb->inp_route,
(so->so_options & SO_DONTROUTE), 0);
}
/*
- * Be careful not to send data and/or FIN on SYN segments
- * in cases when no CC option will be sent.
+ * Be careful not to send data and/or FIN on SYN segments.
* This measure is needed to prevent interoperability problems
* with not fully conformant TCP implementations.
*/
- if ((flags & TH_SYN) &&
- ((tp->t_flags & TF_NOOPT) || !(tp->t_flags & TF_REQ_CC) ||
- ((flags & TH_ACK) && !(tp->t_flags & TF_RCVD_CC)))) {
+ if ((flags & TH_SYN) && (tp->t_flags & TF_NOOPT)) {
len = 0;
flags &= ~TH_FIN;
}
/*
* If FIN has been sent but not acked,
* but we haven't been called to retransmit,
- * len will be -1. Otherwise, window shrank
+ * len will be < 0. Otherwise, window shrank
* after we sent into it. If window shrank to 0,
* cancel pending retransmit, pull snd_nxt back
* to (closed) window, and set the persist timer
* close completely, just wait for an ACK.
*/
len = 0;
- if (win == 0) {
+ if (sendwin == 0) {
tp->t_timer[TCPT_REXMT] = 0;
tp->t_rxtshift = 0;
tp->snd_nxt = tp->snd_una;
tcp_setpersist(tp);
}
}
+
+ /*
+ * len will be >= 0 after this point. Truncate to the maximum
+ * segment length and ensure that FIN is removed if the length
+ * no longer contains the last data byte.
+ */
if (len > tp->t_maxseg) {
len = tp->t_maxseg;
howmuchsent += len;
sendalot = 1;
}
- if (SEQ_LT(tp->snd_nxt + len, tp->snd_una + so->so_snd.sb_cc))
- flags &= ~TH_FIN;
+ if (sack_rxmit) {
+ if (SEQ_LT(p->rxmit + len, tp->snd_una + so->so_snd.sb_cc))
+ flags &= ~TH_FIN;
+ } else {
+ if (SEQ_LT(tp->snd_nxt + len, tp->snd_una + so->so_snd.sb_cc))
+ flags &= ~TH_FIN;
+ }
if (tp->t_flags & TF_SLOWLINK && slowlink_wsize > 0 ) /* Clips window size for slow links */
- win = min(sbspace(&so->so_rcv), slowlink_wsize);
+ recwin = min(sbspace(&so->so_rcv), slowlink_wsize);
else
- win = sbspace(&so->so_rcv);
+ recwin = sbspace(&so->so_rcv);
/*
- * Sender silly window avoidance. If connection is idle
- * and can send all data, a maximum segment,
- * at least a maximum default-size segment do it,
- * or are forced, do it; otherwise don't bother.
- * If peer's buffer is tiny, then send
- * when window is at least half open.
- * If retransmitting (possibly after persist timer forced us
- * to send into a small window), then must resend.
+ * Sender silly window avoidance. We transmit under the following
+ * conditions when len is non-zero:
+ *
+ * - We have a full segment
+ * - This is the last buffer in a write()/send() and we are
+ * either idle or running NODELAY
+ * - we've timed out (e.g. persist timer)
+ * - we have more then 1/2 the maximum send window's worth of
+ * data (receiver may be limited the window size)
+ * - we need to retransmit
*/
if (len) {
if (len == tp->t_maxseg)
goto send;
if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0)
goto send;
- if (SEQ_LT(tp->snd_nxt, tp->snd_max))
+ if (SEQ_LT(tp->snd_nxt, tp->snd_max)) /* retransmit case */
+ goto send;
+ if (sack_rxmit)
goto send;
}
* next expected input). If the difference is at least two
* max size segments, or at least 50% of the maximum possible
* window, then want to send a window update to peer.
+ * Skip this if the connection is in T/TCP half-open state.
*/
- if (win > 0) {
+ if (recwin > 0 && !(tp->t_flags & TF_NEEDSYN)) {
/*
* "adv" is the amount we can increase the window,
* taking into account that we are limited by
* TCP_MAXWIN << tp->rcv_scale.
*/
- long adv = min(win, (long)TCP_MAXWIN << tp->rcv_scale) -
+ long adv = min(recwin, (long)TCP_MAXWIN << tp->rcv_scale) -
(tp->rcv_adv - tp->rcv_nxt);
if (adv >= (long) (2 * tp->t_maxseg))
}
/*
- * Send if we owe peer an ACK.
+ * Send if we owe the peer an ACK, RST, SYN, or urgent data. ACKNOW
+ * is also a catch-all for the retransmit timer timeout case.
*/
if (tp->t_flags & TF_ACKNOW)
goto send;
goto send;
/*
* If our state indicates that FIN should be sent
- * and we have not yet done so, or we're retransmitting the FIN,
- * then we need to send.
+ * and we have not yet done so, then we need to send.
*/
if (flags & TH_FIN &&
((tp->t_flags & TF_SENTFIN) == 0 || tp->snd_nxt == tp->snd_una))
goto send;
-
+ /*
+ * In SACK, it is possible for tcp_output to fail to send a segment
+ * after the retransmission timer has been turned off. Make sure
+ * that the retransmission timer is set.
+ */
+ if (tp->sack_enable && SEQ_GT(tp->snd_max, tp->snd_una) &&
+ tp->t_timer[TCPT_REXMT] == 0 &&
+ tp->t_timer[TCPT_PERSIST] == 0) {
+ tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
+ goto just_return;
+ }
/*
* TCP window updates are not reliable, rather a polling protocol
* using ``persist'' packets is used to insure receipt of window
tp->t_rxtshift = 0;
tcp_setpersist(tp);
}
-
+just_return:
/*
* If there is no reason to send a segment, just return.
* but if there is some packets left in the packet list, send them now.
optlen += TCPOLEN_TSTAMP_APPA;
}
- /*
- * Send `CC-family' options if our side wants to use them (TF_REQ_CC),
- * options are allowed (!TF_NOOPT) and it's not a RST.
- */
- if ((tp->t_flags & (TF_REQ_CC|TF_NOOPT)) == TF_REQ_CC &&
- (flags & TH_RST) == 0) {
- switch (flags & (TH_SYN|TH_ACK)) {
- /*
- * This is a normal ACK, send CC if we received CC before
- * from our peer.
+ if (tp->sack_enable && ((tp->t_flags & TF_NOOPT) == 0)) {
+ /*
+ * Tack on the SACK permitted option *last*.
+ * And do padding of options after tacking this on.
+ * This is because of MSS, TS, WinScale and Signatures are
+ * all present, we have just 2 bytes left for the SACK
+ * permitted option, which is just enough.
*/
- case TH_ACK:
- if (!(tp->t_flags & TF_RCVD_CC))
- break;
- /*FALLTHROUGH*/
-
/*
- * We can only get here in T/TCP's SYN_SENT* state, when
- * we're a sending a non-SYN segment without waiting for
- * the ACK of our SYN. A check above assures that we only
- * do this if our peer understands T/TCP.
+ * If this is the first SYN of connection (not a SYN
+ * ACK), include SACK permitted option. If this is a
+ * SYN ACK, include SACK permitted option if peer has
+ * already done so. This is only for active connect,
+ * since the syncache takes care of the passive connect.
*/
- case 0:
- opt[optlen++] = TCPOPT_NOP;
- opt[optlen++] = TCPOPT_NOP;
- opt[optlen++] = TCPOPT_CC;
- opt[optlen++] = TCPOLEN_CC;
- *(u_int32_t *)&opt[optlen] = htonl(tp->cc_send);
-
- optlen += 4;
- break;
+ if ((flags & TH_SYN) &&
+ (!(flags & TH_ACK) || (tp->t_flags & TF_SACK_PERMIT))) {
+ u_char *bp;
+ bp = (u_char *)opt + optlen;
+
+ *bp++ = TCPOPT_SACK_PERMITTED;
+ *bp++ = TCPOLEN_SACK_PERMITTED;
+ optlen += TCPOLEN_SACK_PERMITTED;
+ }
/*
- * This is our initial SYN, check whether we have to use
- * CC or CC.new.
+ * Send SACKs if necessary. This should be the last
+ * option processed. Only as many SACKs are sent as
+ * are permitted by the maximum options size.
+ *
+ * In general, SACK blocks consume 8*n+2 bytes.
+ * So a full size SACK blocks option is 34 bytes
+ * (to generate 4 SACK blocks). At a minimum,
+ * we need 10 bytes (to generate 1 SACK block).
+ * If TCP Timestamps (12 bytes) and TCP Signatures
+ * (18 bytes) are both present, we'll just have
+ * 10 bytes for SACK options 40 - (12 + 18).
*/
- case TH_SYN:
- opt[optlen++] = TCPOPT_NOP;
- opt[optlen++] = TCPOPT_NOP;
- opt[optlen++] = tp->t_flags & TF_SENDCCNEW ?
- TCPOPT_CCNEW : TCPOPT_CC;
- opt[optlen++] = TCPOLEN_CC;
- *(u_int32_t *)&opt[optlen] = htonl(tp->cc_send);
- optlen += 4;
- break;
+ if (TCPS_HAVEESTABLISHED(tp->t_state) &&
+ (tp->t_flags & TF_SACK_PERMIT) && tp->rcv_numsacks > 0 &&
+ MAX_TCPOPTLEN - optlen - 2 >= TCPOLEN_SACK) {
+ int nsack, sackoptlen, padlen;
+ u_char *bp = (u_char *)opt + optlen;
+ u_int32_t *lp;
- /*
- * This is a SYN,ACK; send CC and CC.echo if we received
- * CC from our peer.
- */
- case (TH_SYN|TH_ACK):
- if (tp->t_flags & TF_RCVD_CC) {
- opt[optlen++] = TCPOPT_NOP;
- opt[optlen++] = TCPOPT_NOP;
- opt[optlen++] = TCPOPT_CC;
- opt[optlen++] = TCPOLEN_CC;
- *(u_int32_t *)&opt[optlen] =
- htonl(tp->cc_send);
- optlen += 4;
- opt[optlen++] = TCPOPT_NOP;
- opt[optlen++] = TCPOPT_NOP;
- opt[optlen++] = TCPOPT_CCECHO;
- opt[optlen++] = TCPOLEN_CC;
- *(u_int32_t *)&opt[optlen] =
- htonl(tp->cc_recv);
- optlen += 4;
+ nsack = (MAX_TCPOPTLEN - optlen - 2) / TCPOLEN_SACK;
+ nsack = min(nsack, tp->rcv_numsacks);
+ sackoptlen = (2 + nsack * TCPOLEN_SACK);
+
+ /*
+ * First we need to pad options so that the
+ * SACK blocks can start at a 4-byte boundary
+ * (sack option and length are at a 2 byte offset).
+ */
+ padlen = (MAX_TCPOPTLEN - optlen - sackoptlen) % 4;
+ optlen += padlen;
+ while (padlen-- > 0)
+ *bp++ = TCPOPT_NOP;
+
+ tcpstat.tcps_sack_send_blocks++;
+ *bp++ = TCPOPT_SACK;
+ *bp++ = sackoptlen;
+ lp = (u_int32_t *)bp;
+ for (i = 0; i < nsack; i++) {
+ struct sackblk sack = tp->sackblks[i];
+ *lp++ = htonl(sack.start);
+ *lp++ = htonl(sack.end);
}
- break;
+ optlen += sackoptlen;
}
- }
+ }
+
+ /* Pad TCP options to a 4 byte boundary */
+ if (optlen < MAX_TCPOPTLEN && (optlen % sizeof(u_int32_t))) {
+ int pad = sizeof(u_int32_t) - (optlen % sizeof(u_int32_t));
+ u_char *bp = (u_char *)opt + optlen;
+
+ optlen += pad;
+ while (pad) {
+ *bp++ = TCPOPT_EOL;
+ pad--;
+ }
+ }
+
+ hdrlen += optlen;
- hdrlen += optlen;
#if INET6
if (isipv6)
ipoptlen = ip6_optlen(tp->t_inpcb);
if (tp->t_inpcb->inp_options) {
ipoptlen = tp->t_inpcb->inp_options->m_len -
offsetof(struct ipoption, ipopt_list);
- } else {
+ } else
ipoptlen = 0;
- }
}
#if IPSEC
if (ipsec_bypass == 0)
* case, since we know we aren't doing a retransmission.
* (retransmit and persist are mutually exclusive...)
*/
- if (len || (flags & (TH_SYN|TH_FIN)) || tp->t_timer[TCPT_PERSIST])
- th->th_seq = htonl(tp->snd_nxt);
- else
- th->th_seq = htonl(tp->snd_max);
+ if (sack_rxmit == 0) {
+ if (len || (flags & (TH_SYN|TH_FIN)) || tp->t_timer[TCPT_PERSIST])
+ th->th_seq = htonl(tp->snd_nxt);
+ else
+ th->th_seq = htonl(tp->snd_max);
+ } else {
+ th->th_seq = htonl(p->rxmit);
+ p->rxmit += len;
+ tp->sackhint.sack_bytes_rexmit += len;
+ }
th->th_ack = htonl(tp->rcv_nxt);
if (optlen) {
bcopy(opt, th + 1, optlen);
* Calculate receive window. Don't shrink window,
* but avoid silly window syndrome.
*/
- if (win < (long)(so->so_rcv.sb_hiwat / 4) && win < (long)tp->t_maxseg)
- win = 0;
- if (win < (long)(tp->rcv_adv - tp->rcv_nxt))
- win = (long)(tp->rcv_adv - tp->rcv_nxt);
+ if (recwin < (long)(so->so_rcv.sb_hiwat / 4) && recwin < (long)tp->t_maxseg)
+ recwin = 0;
+ if (recwin < (long)(tp->rcv_adv - tp->rcv_nxt))
+ recwin = (long)(tp->rcv_adv - tp->rcv_nxt);
if (tp->t_flags & TF_SLOWLINK && slowlink_wsize > 0) {
- if (win > (long)slowlink_wsize)
- win = slowlink_wsize;
- th->th_win = htons((u_short) (win>>tp->rcv_scale));
+ if (recwin > (long)slowlink_wsize)
+ recwin = slowlink_wsize;
+ th->th_win = htons((u_short) (recwin>>tp->rcv_scale));
}
else {
-
- if (win > (long)TCP_MAXWIN << tp->rcv_scale)
- win = (long)TCP_MAXWIN << tp->rcv_scale;
- th->th_win = htons((u_short) (win>>tp->rcv_scale));
+ if (recwin > (long)TCP_MAXWIN << tp->rcv_scale)
+ recwin = (long)TCP_MAXWIN << tp->rcv_scale;
+ th->th_win = htons((u_short) (recwin>>tp->rcv_scale));
}
- /*
- * Adjust the RXWIN0SENT flag - indicate that we have advertised
- * a 0 window. This may cause the remote transmitter to stall. This
- * flag tells soreceive() to disable delayed acknowledgements when
- * draining the buffer. This can occur if the receiver is attempting
- * to read more data then can be buffered prior to transmitting on
- * the connection.
- */
- if (win == 0)
- tp->t_flags |= TF_RXWIN0SENT;
- else
- tp->t_flags &= ~TF_RXWIN0SENT;
-
+ /*
+ * Adjust the RXWIN0SENT flag - indicate that we have advertised
+ * a 0 window. This may cause the remote transmitter to stall. This
+ * flag tells soreceive() to disable delayed acknowledgements when
+ * draining the buffer. This can occur if the receiver is attempting
+ * to read more data then can be buffered prior to transmitting on
+ * the connection.
+ */
+ if (recwin == 0)
+ tp->t_flags |= TF_RXWIN0SENT;
+ else
+ tp->t_flags &= ~TF_RXWIN0SENT;
if (SEQ_GT(tp->snd_up, tp->snd_nxt)) {
th->th_urp = htons((u_short)(tp->snd_up - tp->snd_nxt));
th->th_flags |= TH_URG;
if (len + optlen)
th->th_sum = in_addword(th->th_sum,
htons((u_short)(optlen + len)));
-
- /* IP version must be set here for ipv4/ipv6 checking later */
- KASSERT(ip->ip_v == IPVERSION,
- ("%s: IP version incorrect: %d", __FUNCTION__, ip->ip_v));
}
/*
tp->t_flags |= TF_SENTFIN;
}
}
+ if (sack_rxmit)
+ goto timer;
tp->snd_nxt += len;
if (SEQ_GT(tp->snd_nxt, tp->snd_max)) {
tp->snd_max = tp->snd_nxt;
* Initialize shift counter which is used for backoff
* of retransmit time.
*/
+timer:
if (tp->t_timer[TCPT_REXMT] == 0 &&
- tp->snd_nxt != tp->snd_una) {
- tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
+ ((sack_rxmit && tp->snd_nxt != tp->snd_max) ||
+ tp->snd_nxt != tp->snd_una)) {
if (tp->t_timer[TCPT_PERSIST]) {
tp->t_timer[TCPT_PERSIST] = 0;
tp->t_rxtshift = 0;
}
+ tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
}
- } else
- if (SEQ_GT(tp->snd_nxt + len, tp->snd_max))
+ } else {
+ /*
+ * Persist case, update snd_max but since we are in
+ * persist mode (no window) we do not update snd_nxt.
+ */
+ int xlen = len;
+ if (flags & TH_SYN)
+ ++xlen;
+ if (flags & TH_FIN) {
+ ++xlen;
+ tp->t_flags |= TF_SENTFIN;
+ }
+ if (SEQ_GT(tp->snd_nxt + xlen, tp->snd_max))
tp->snd_max = tp->snd_nxt + len;
+ }
#if TCPDEBUG
/*
error = 0;
packchain_looped++;
tcpstat.tcps_sndtotal++;
- if (win > 0 && SEQ_GT(tp->rcv_nxt+win, tp->rcv_adv))
- tp->rcv_adv = tp->rcv_nxt + win;
+ if (recwin > 0 && SEQ_GT(tp->rcv_nxt+recwin, tp->rcv_adv))
+ tp->rcv_adv = tp->rcv_nxt + recwin;
tp->last_ack_sent = tp->rcv_nxt;
tp->t_flags &= ~(TF_ACKNOW|TF_DELACK);
goto again;
* We know that the packet was lost, so back out the
* sequence number advance, if any.
*/
- if (tp->t_force == 0 || !tp->t_timer[TCPT_PERSIST]) {
+ if (tp->t_force == 0 || tp->t_timer[TCPT_PERSIST] == 0) {
/*
* No need to check for TH_FIN here because
* the TF_SENTFIN flag handles that case.
*/
- if ((flags & TH_SYN) == 0)
- tp->snd_nxt -= howmuchsent;
+ if ((flags & TH_SYN) == 0) {
+ if (sack_rxmit) {
+ p->rxmit -= howmuchsent;
+ tp->sackhint.sack_bytes_rexmit -= howmuchsent;
+ } else
+ tp->snd_nxt -= howmuchsent;
+ }
}
howmuchsent = 0;
out:
* then remember the size of the advertised window.
* Any pending ACK has now been sent.
*/
- if (win > 0 && SEQ_GT(tp->rcv_nxt+win, tp->rcv_adv))
- tp->rcv_adv = tp->rcv_nxt + win;
+ if (recwin > 0 && SEQ_GT(tp->rcv_nxt+recwin, tp->rcv_adv))
+ tp->rcv_adv = tp->rcv_nxt + recwin;
tp->last_ack_sent = tp->rcv_nxt;
tp->t_flags &= ~(TF_ACKNOW|TF_DELACK);
projects / apple / xnu.git / blobdiff