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unneback |
/*
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* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)tcp_output.c 8.4 (Berkeley) 5/24/95
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* $Id: tcp_output.c,v 1.2 2001-09-27 12:01:56 chris Exp $
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*/
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#include "opt_tcpdebug.h"
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#include <sys/param.h>
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#include <sys/queue.h>
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#include <sys/systm.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/protosw.h>
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#include <sys/socket.h>
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#include <sys/socketvar.h>
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#include <sys/errno.h>
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#include <net/route.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#include <netinet/in_pcb.h>
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#include <netinet/ip_var.h>
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#include <netinet/tcp.h>
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#define TCPOUTFLAGS
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#include <netinet/tcp_fsm.h>
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#include <netinet/tcp_seq.h>
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#include <netinet/tcp_timer.h>
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#include <netinet/tcp_var.h>
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#include <netinet/tcpip.h>
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#ifdef TCPDEBUG
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#include <netinet/tcp_debug.h>
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#endif
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#ifdef notyet
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extern struct mbuf *m_copypack();
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#endif
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/*
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* Tcp output routine: figure out what should be sent and send it.
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*/
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int
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tcp_output(tp)
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register struct tcpcb *tp;
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{
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register struct socket *so = tp->t_inpcb->inp_socket;
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register long len, win;
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int off, flags, error;
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register struct mbuf *m;
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register struct tcpiphdr *ti;
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u_char opt[TCP_MAXOLEN];
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unsigned optlen, hdrlen;
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int idle, sendalot;
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struct rmxp_tao *taop;
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struct rmxp_tao tao_noncached;
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/*
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* Determine length of data that should be transmitted,
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* and flags that will be used.
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* If there is some data or critical controls (SYN, RST)
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* to send, then transmit; otherwise, investigate further.
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*/
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idle = (tp->snd_max == tp->snd_una);
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if (idle && tp->t_idle >= tp->t_rxtcur)
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/*
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* We have been idle for "a while" and no acks are
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* expected to clock out any data we send --
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* slow start to get ack "clock" running again.
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*/
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tp->snd_cwnd = tp->t_maxseg;
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again:
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sendalot = 0;
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off = tp->snd_nxt - tp->snd_una;
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win = min(tp->snd_wnd, tp->snd_cwnd);
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flags = tcp_outflags[tp->t_state];
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/*
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* Get standard flags, and add SYN or FIN if requested by 'hidden'
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* state flags.
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*/
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if (tp->t_flags & TF_NEEDFIN)
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flags |= TH_FIN;
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if (tp->t_flags & TF_NEEDSYN)
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flags |= TH_SYN;
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/*
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* If in persist timeout with window of 0, send 1 byte.
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* Otherwise, if window is small but nonzero
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* and timer expired, we will send what we can
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* and go to transmit state.
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*/
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if (tp->t_force) {
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if (win == 0) {
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/*
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* If we still have some data to send, then
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* clear the FIN bit. Usually this would
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* happen below when it realizes that we
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* aren't sending all the data. However,
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* if we have exactly 1 byte of unset data,
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* then it won't clear the FIN bit below,
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* and if we are in persist state, we wind
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* up sending the packet without recording
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* that we sent the FIN bit.
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*
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* We can't just blindly clear the FIN bit,
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* because if we don't have any more data
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* to send then the probe will be the FIN
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* itself.
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*/
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if (off < so->so_snd.sb_cc)
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flags &= ~TH_FIN;
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win = 1;
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} else {
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tp->t_timer[TCPT_PERSIST] = 0;
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tp->t_rxtshift = 0;
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}
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}
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len = min(so->so_snd.sb_cc, win) - off;
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if ((taop = tcp_gettaocache(tp->t_inpcb)) == NULL) {
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taop = &tao_noncached;
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bzero(taop, sizeof(*taop));
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}
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| 159 |
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/*
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* Lop off SYN bit if it has already been sent. However, if this
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* is SYN-SENT state and if segment contains data and if we don't
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* know that foreign host supports TAO, suppress sending segment.
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*/
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if ((flags & TH_SYN) && SEQ_GT(tp->snd_nxt, tp->snd_una)) {
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flags &= ~TH_SYN;
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off--, len++;
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if (len > 0 && tp->t_state == TCPS_SYN_SENT &&
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taop->tao_ccsent == 0)
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return 0;
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}
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| 171 |
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| 172 |
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/*
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| 173 |
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* Be careful not to send data and/or FIN on SYN segments
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| 174 |
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* in cases when no CC option will be sent.
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* This measure is needed to prevent interoperability problems
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* with not fully conformant TCP implementations.
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*/
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if ((flags & TH_SYN) &&
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((tp->t_flags & TF_NOOPT) || !(tp->t_flags & TF_REQ_CC) ||
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((flags & TH_ACK) && !(tp->t_flags & TF_RCVD_CC)))) {
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len = 0;
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flags &= ~TH_FIN;
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}
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| 184 |
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| 185 |
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if (len < 0) {
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/*
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* If FIN has been sent but not acked,
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* but we haven't been called to retransmit,
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* len will be -1. Otherwise, window shrank
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* after we sent into it. If window shrank to 0,
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* cancel pending retransmit, pull snd_nxt back
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* to (closed) window, and set the persist timer
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* if it isn't already going. If the window didn't
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* close completely, just wait for an ACK.
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*/
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len = 0;
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if (win == 0) {
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| 198 |
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tp->t_timer[TCPT_REXMT] = 0;
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tp->t_rxtshift = 0;
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| 200 |
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tp->snd_nxt = tp->snd_una;
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| 201 |
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if (tp->t_timer[TCPT_PERSIST] == 0)
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| 202 |
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tcp_setpersist(tp);
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| 203 |
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}
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| 204 |
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}
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| 205 |
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if (len > tp->t_maxseg) {
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| 206 |
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len = tp->t_maxseg;
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| 207 |
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sendalot = 1;
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| 208 |
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}
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| 209 |
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if (SEQ_LT(tp->snd_nxt + len, tp->snd_una + so->so_snd.sb_cc))
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flags &= ~TH_FIN;
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| 211 |
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| 212 |
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win = sbspace(&so->so_rcv);
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| 214 |
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/*
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| 215 |
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* Sender silly window avoidance. If connection is idle
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| 216 |
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* and can send all data, a maximum segment,
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| 217 |
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* at least a maximum default-size segment do it,
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| 218 |
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* or are forced, do it; otherwise don't bother.
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| 219 |
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* If peer's buffer is tiny, then send
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| 220 |
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* when window is at least half open.
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| 221 |
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* If retransmitting (possibly after persist timer forced us
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| 222 |
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* to send into a small window), then must resend.
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| 223 |
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*/
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| 224 |
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if (len) {
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| 225 |
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if (len == tp->t_maxseg)
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| 226 |
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goto send;
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| 227 |
|
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if ((idle || tp->t_flags & TF_NODELAY) &&
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| 228 |
|
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(tp->t_flags & TF_NOPUSH) == 0 &&
|
| 229 |
|
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len + off >= so->so_snd.sb_cc)
|
| 230 |
|
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goto send;
|
| 231 |
|
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if (tp->t_force)
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| 232 |
|
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goto send;
|
| 233 |
|
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if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0)
|
| 234 |
|
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goto send;
|
| 235 |
|
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if (SEQ_LT(tp->snd_nxt, tp->snd_max))
|
| 236 |
|
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goto send;
|
| 237 |
|
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}
|
| 238 |
|
|
|
| 239 |
|
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/*
|
| 240 |
|
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* Compare available window to amount of window
|
| 241 |
|
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* known to peer (as advertised window less
|
| 242 |
|
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* next expected input). If the difference is at least two
|
| 243 |
|
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* max size segments, or at least 50% of the maximum possible
|
| 244 |
|
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* window, then want to send a window update to peer.
|
| 245 |
|
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*/
|
| 246 |
|
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if (win > 0) {
|
| 247 |
|
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/*
|
| 248 |
|
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* "adv" is the amount we can increase the window,
|
| 249 |
|
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* taking into account that we are limited by
|
| 250 |
|
|
* TCP_MAXWIN << tp->rcv_scale.
|
| 251 |
|
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*/
|
| 252 |
|
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long adv = min(win, (long)TCP_MAXWIN << tp->rcv_scale) -
|
| 253 |
|
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(tp->rcv_adv - tp->rcv_nxt);
|
| 254 |
|
|
|
| 255 |
|
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if (adv >= (long) (2 * tp->t_maxseg))
|
| 256 |
|
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goto send;
|
| 257 |
|
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if (2 * adv >= (long) so->so_rcv.sb_hiwat)
|
| 258 |
|
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goto send;
|
| 259 |
|
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}
|
| 260 |
|
|
|
| 261 |
|
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/*
|
| 262 |
|
|
* Send if we owe peer an ACK.
|
| 263 |
|
|
*/
|
| 264 |
|
|
if (tp->t_flags & TF_ACKNOW)
|
| 265 |
|
|
goto send;
|
| 266 |
|
|
if ((flags & TH_RST) ||
|
| 267 |
|
|
((flags & TH_SYN) && (tp->t_flags & TF_NEEDSYN) == 0))
|
| 268 |
|
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goto send;
|
| 269 |
|
|
if (SEQ_GT(tp->snd_up, tp->snd_una))
|
| 270 |
|
|
goto send;
|
| 271 |
|
|
/*
|
| 272 |
|
|
* If our state indicates that FIN should be sent
|
| 273 |
|
|
* and we have not yet done so, or we're retransmitting the FIN,
|
| 274 |
|
|
* then we need to send.
|
| 275 |
|
|
*/
|
| 276 |
|
|
if (flags & TH_FIN &&
|
| 277 |
|
|
((tp->t_flags & TF_SENTFIN) == 0 || tp->snd_nxt == tp->snd_una))
|
| 278 |
|
|
goto send;
|
| 279 |
|
|
|
| 280 |
|
|
/*
|
| 281 |
|
|
* TCP window updates are not reliable, rather a polling protocol
|
| 282 |
|
|
* using ``persist'' packets is used to insure receipt of window
|
| 283 |
|
|
* updates. The three ``states'' for the output side are:
|
| 284 |
|
|
* idle not doing retransmits or persists
|
| 285 |
|
|
* persisting to move a small or zero window
|
| 286 |
|
|
* (re)transmitting and thereby not persisting
|
| 287 |
|
|
*
|
| 288 |
|
|
* tp->t_timer[TCPT_PERSIST]
|
| 289 |
|
|
* is set when we are in persist state.
|
| 290 |
|
|
* tp->t_force
|
| 291 |
|
|
* is set when we are called to send a persist packet.
|
| 292 |
|
|
* tp->t_timer[TCPT_REXMT]
|
| 293 |
|
|
* is set when we are retransmitting
|
| 294 |
|
|
* The output side is idle when both timers are zero.
|
| 295 |
|
|
*
|
| 296 |
|
|
* If send window is too small, there is data to transmit, and no
|
| 297 |
|
|
* retransmit or persist is pending, then go to persist state.
|
| 298 |
|
|
* If nothing happens soon, send when timer expires:
|
| 299 |
|
|
* if window is nonzero, transmit what we can,
|
| 300 |
|
|
* otherwise force out a byte.
|
| 301 |
|
|
*/
|
| 302 |
|
|
if (so->so_snd.sb_cc && tp->t_timer[TCPT_REXMT] == 0 &&
|
| 303 |
|
|
tp->t_timer[TCPT_PERSIST] == 0) {
|
| 304 |
|
|
tp->t_rxtshift = 0;
|
| 305 |
|
|
tcp_setpersist(tp);
|
| 306 |
|
|
}
|
| 307 |
|
|
|
| 308 |
|
|
/*
|
| 309 |
|
|
* No reason to send a segment, just return.
|
| 310 |
|
|
*/
|
| 311 |
|
|
return (0);
|
| 312 |
|
|
|
| 313 |
|
|
send:
|
| 314 |
|
|
/*
|
| 315 |
|
|
* Before ESTABLISHED, force sending of initial options
|
| 316 |
|
|
* unless TCP set not to do any options.
|
| 317 |
|
|
* NOTE: we assume that the IP/TCP header plus TCP options
|
| 318 |
|
|
* always fit in a single mbuf, leaving room for a maximum
|
| 319 |
|
|
* link header, i.e.
|
| 320 |
|
|
* max_linkhdr + sizeof (struct tcpiphdr) + optlen <= MHLEN
|
| 321 |
|
|
*/
|
| 322 |
|
|
optlen = 0;
|
| 323 |
|
|
hdrlen = sizeof (struct tcpiphdr);
|
| 324 |
|
|
if (flags & TH_SYN) {
|
| 325 |
|
|
tp->snd_nxt = tp->iss;
|
| 326 |
|
|
if ((tp->t_flags & TF_NOOPT) == 0) {
|
| 327 |
|
|
u_short mss;
|
| 328 |
|
|
|
| 329 |
|
|
opt[0] = TCPOPT_MAXSEG;
|
| 330 |
|
|
opt[1] = TCPOLEN_MAXSEG;
|
| 331 |
|
|
mss = htons((u_short) tcp_mssopt(tp));
|
| 332 |
|
|
(void)memcpy(opt + 2, &mss, sizeof(mss));
|
| 333 |
|
|
optlen = TCPOLEN_MAXSEG;
|
| 334 |
|
|
|
| 335 |
|
|
if ((tp->t_flags & TF_REQ_SCALE) &&
|
| 336 |
|
|
((flags & TH_ACK) == 0 ||
|
| 337 |
|
|
(tp->t_flags & TF_RCVD_SCALE))) {
|
| 338 |
|
|
*((u_long *) (opt + optlen)) = htonl(
|
| 339 |
|
|
TCPOPT_NOP << 24 |
|
| 340 |
|
|
TCPOPT_WINDOW << 16 |
|
| 341 |
|
|
TCPOLEN_WINDOW << 8 |
|
| 342 |
|
|
tp->request_r_scale);
|
| 343 |
|
|
optlen += 4;
|
| 344 |
|
|
}
|
| 345 |
|
|
}
|
| 346 |
|
|
}
|
| 347 |
|
|
|
| 348 |
|
|
/*
|
| 349 |
|
|
* Send a timestamp and echo-reply if this is a SYN and our side
|
| 350 |
|
|
* wants to use timestamps (TF_REQ_TSTMP is set) or both our side
|
| 351 |
|
|
* and our peer have sent timestamps in our SYN's.
|
| 352 |
|
|
*/
|
| 353 |
|
|
if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP &&
|
| 354 |
|
|
(flags & TH_RST) == 0 &&
|
| 355 |
|
|
((flags & TH_ACK) == 0 ||
|
| 356 |
|
|
(tp->t_flags & TF_RCVD_TSTMP))) {
|
| 357 |
|
|
u_long *lp = (u_long *)(opt + optlen);
|
| 358 |
|
|
|
| 359 |
|
|
/* Form timestamp option as shown in appendix A of RFC 1323. */
|
| 360 |
|
|
*lp++ = htonl(TCPOPT_TSTAMP_HDR);
|
| 361 |
|
|
*lp++ = htonl(tcp_now);
|
| 362 |
|
|
*lp = htonl(tp->ts_recent);
|
| 363 |
|
|
optlen += TCPOLEN_TSTAMP_APPA;
|
| 364 |
|
|
}
|
| 365 |
|
|
|
| 366 |
|
|
/*
|
| 367 |
|
|
* Send `CC-family' options if our side wants to use them (TF_REQ_CC),
|
| 368 |
|
|
* options are allowed (!TF_NOOPT) and it's not a RST.
|
| 369 |
|
|
*/
|
| 370 |
|
|
if ((tp->t_flags & (TF_REQ_CC|TF_NOOPT)) == TF_REQ_CC &&
|
| 371 |
|
|
(flags & TH_RST) == 0) {
|
| 372 |
|
|
switch (flags & (TH_SYN|TH_ACK)) {
|
| 373 |
|
|
/*
|
| 374 |
|
|
* This is a normal ACK, send CC if we received CC before
|
| 375 |
|
|
* from our peer.
|
| 376 |
|
|
*/
|
| 377 |
|
|
case TH_ACK:
|
| 378 |
|
|
if (!(tp->t_flags & TF_RCVD_CC))
|
| 379 |
|
|
break;
|
| 380 |
|
|
/*FALLTHROUGH*/
|
| 381 |
|
|
|
| 382 |
|
|
/*
|
| 383 |
|
|
* We can only get here in T/TCP's SYN_SENT* state, when
|
| 384 |
|
|
* we're a sending a non-SYN segment without waiting for
|
| 385 |
|
|
* the ACK of our SYN. A check above assures that we only
|
| 386 |
|
|
* do this if our peer understands T/TCP.
|
| 387 |
|
|
*/
|
| 388 |
|
|
case 0:
|
| 389 |
|
|
opt[optlen++] = TCPOPT_NOP;
|
| 390 |
|
|
opt[optlen++] = TCPOPT_NOP;
|
| 391 |
|
|
opt[optlen++] = TCPOPT_CC;
|
| 392 |
|
|
opt[optlen++] = TCPOLEN_CC;
|
| 393 |
|
|
*(u_int32_t *)&opt[optlen] = htonl(tp->cc_send);
|
| 394 |
|
|
|
| 395 |
|
|
optlen += 4;
|
| 396 |
|
|
break;
|
| 397 |
|
|
|
| 398 |
|
|
/*
|
| 399 |
|
|
* This is our initial SYN, check whether we have to use
|
| 400 |
|
|
* CC or CC.new.
|
| 401 |
|
|
*/
|
| 402 |
|
|
case TH_SYN:
|
| 403 |
|
|
opt[optlen++] = TCPOPT_NOP;
|
| 404 |
|
|
opt[optlen++] = TCPOPT_NOP;
|
| 405 |
|
|
opt[optlen++] = tp->t_flags & TF_SENDCCNEW ?
|
| 406 |
|
|
TCPOPT_CCNEW : TCPOPT_CC;
|
| 407 |
|
|
opt[optlen++] = TCPOLEN_CC;
|
| 408 |
|
|
*(u_int32_t *)&opt[optlen] = htonl(tp->cc_send);
|
| 409 |
|
|
optlen += 4;
|
| 410 |
|
|
break;
|
| 411 |
|
|
|
| 412 |
|
|
/*
|
| 413 |
|
|
* This is a SYN,ACK; send CC and CC.echo if we received
|
| 414 |
|
|
* CC from our peer.
|
| 415 |
|
|
*/
|
| 416 |
|
|
case (TH_SYN|TH_ACK):
|
| 417 |
|
|
if (tp->t_flags & TF_RCVD_CC) {
|
| 418 |
|
|
opt[optlen++] = TCPOPT_NOP;
|
| 419 |
|
|
opt[optlen++] = TCPOPT_NOP;
|
| 420 |
|
|
opt[optlen++] = TCPOPT_CC;
|
| 421 |
|
|
opt[optlen++] = TCPOLEN_CC;
|
| 422 |
|
|
*(u_int32_t *)&opt[optlen] =
|
| 423 |
|
|
htonl(tp->cc_send);
|
| 424 |
|
|
optlen += 4;
|
| 425 |
|
|
opt[optlen++] = TCPOPT_NOP;
|
| 426 |
|
|
opt[optlen++] = TCPOPT_NOP;
|
| 427 |
|
|
opt[optlen++] = TCPOPT_CCECHO;
|
| 428 |
|
|
opt[optlen++] = TCPOLEN_CC;
|
| 429 |
|
|
*(u_int32_t *)&opt[optlen] =
|
| 430 |
|
|
htonl(tp->cc_recv);
|
| 431 |
|
|
optlen += 4;
|
| 432 |
|
|
}
|
| 433 |
|
|
break;
|
| 434 |
|
|
}
|
| 435 |
|
|
}
|
| 436 |
|
|
|
| 437 |
|
|
hdrlen += optlen;
|
| 438 |
|
|
|
| 439 |
|
|
/*
|
| 440 |
|
|
* Adjust data length if insertion of options will
|
| 441 |
|
|
* bump the packet length beyond the t_maxopd length.
|
| 442 |
|
|
* Clear the FIN bit because we cut off the tail of
|
| 443 |
|
|
* the segment.
|
| 444 |
|
|
*/
|
| 445 |
|
|
if (len + optlen > tp->t_maxopd) {
|
| 446 |
|
|
/*
|
| 447 |
|
|
* If there is still more to send, don't close the connection.
|
| 448 |
|
|
*/
|
| 449 |
|
|
flags &= ~TH_FIN;
|
| 450 |
|
|
len = tp->t_maxopd - optlen;
|
| 451 |
|
|
sendalot = 1;
|
| 452 |
|
|
}
|
| 453 |
|
|
|
| 454 |
|
|
/*#ifdef DIAGNOSTIC*/
|
| 455 |
|
|
if (max_linkhdr + hdrlen > MHLEN)
|
| 456 |
|
|
panic("tcphdr too big");
|
| 457 |
|
|
/*#endif*/
|
| 458 |
|
|
|
| 459 |
|
|
/*
|
| 460 |
|
|
* Grab a header mbuf, attaching a copy of data to
|
| 461 |
|
|
* be transmitted, and initialize the header from
|
| 462 |
|
|
* the template for sends on this connection.
|
| 463 |
|
|
*/
|
| 464 |
|
|
if (len) {
|
| 465 |
|
|
if (tp->t_force && len == 1)
|
| 466 |
|
|
tcpstat.tcps_sndprobe++;
|
| 467 |
|
|
else if (SEQ_LT(tp->snd_nxt, tp->snd_max)) {
|
| 468 |
|
|
tcpstat.tcps_sndrexmitpack++;
|
| 469 |
|
|
tcpstat.tcps_sndrexmitbyte += len;
|
| 470 |
|
|
} else {
|
| 471 |
|
|
tcpstat.tcps_sndpack++;
|
| 472 |
|
|
tcpstat.tcps_sndbyte += len;
|
| 473 |
|
|
}
|
| 474 |
|
|
#ifdef notyet
|
| 475 |
|
|
if ((m = m_copypack(so->so_snd.sb_mb, off,
|
| 476 |
|
|
(int)len, max_linkhdr + hdrlen)) == 0) {
|
| 477 |
|
|
error = ENOBUFS;
|
| 478 |
|
|
goto out;
|
| 479 |
|
|
}
|
| 480 |
|
|
/*
|
| 481 |
|
|
* m_copypack left space for our hdr; use it.
|
| 482 |
|
|
*/
|
| 483 |
|
|
m->m_len += hdrlen;
|
| 484 |
|
|
m->m_data -= hdrlen;
|
| 485 |
|
|
#else
|
| 486 |
|
|
MGETHDR(m, M_DONTWAIT, MT_HEADER);
|
| 487 |
|
|
if (m == NULL) {
|
| 488 |
|
|
error = ENOBUFS;
|
| 489 |
|
|
goto out;
|
| 490 |
|
|
}
|
| 491 |
|
|
m->m_data += max_linkhdr;
|
| 492 |
|
|
m->m_len = hdrlen;
|
| 493 |
|
|
if (len <= MHLEN - hdrlen - max_linkhdr) {
|
| 494 |
|
|
m_copydata(so->so_snd.sb_mb, off, (int) len,
|
| 495 |
|
|
mtod(m, caddr_t) + hdrlen);
|
| 496 |
|
|
m->m_len += len;
|
| 497 |
|
|
} else {
|
| 498 |
|
|
m->m_next = m_copy(so->so_snd.sb_mb, off, (int) len);
|
| 499 |
|
|
if (m->m_next == 0) {
|
| 500 |
|
|
(void) m_free(m);
|
| 501 |
|
|
error = ENOBUFS;
|
| 502 |
|
|
goto out;
|
| 503 |
|
|
}
|
| 504 |
|
|
}
|
| 505 |
|
|
#endif
|
| 506 |
|
|
/*
|
| 507 |
|
|
* If we're sending everything we've got, set PUSH.
|
| 508 |
|
|
* (This will keep happy those implementations which only
|
| 509 |
|
|
* give data to the user when a buffer fills or
|
| 510 |
|
|
* a PUSH comes in.)
|
| 511 |
|
|
*/
|
| 512 |
|
|
if (off + len == so->so_snd.sb_cc)
|
| 513 |
|
|
flags |= TH_PUSH;
|
| 514 |
|
|
} else {
|
| 515 |
|
|
if (tp->t_flags & TF_ACKNOW)
|
| 516 |
|
|
tcpstat.tcps_sndacks++;
|
| 517 |
|
|
else if (flags & (TH_SYN|TH_FIN|TH_RST))
|
| 518 |
|
|
tcpstat.tcps_sndctrl++;
|
| 519 |
|
|
else if (SEQ_GT(tp->snd_up, tp->snd_una))
|
| 520 |
|
|
tcpstat.tcps_sndurg++;
|
| 521 |
|
|
else
|
| 522 |
|
|
tcpstat.tcps_sndwinup++;
|
| 523 |
|
|
|
| 524 |
|
|
MGETHDR(m, M_DONTWAIT, MT_HEADER);
|
| 525 |
|
|
if (m == NULL) {
|
| 526 |
|
|
error = ENOBUFS;
|
| 527 |
|
|
goto out;
|
| 528 |
|
|
}
|
| 529 |
|
|
m->m_data += max_linkhdr;
|
| 530 |
|
|
m->m_len = hdrlen;
|
| 531 |
|
|
}
|
| 532 |
|
|
m->m_pkthdr.rcvif = (struct ifnet *)0;
|
| 533 |
|
|
ti = mtod(m, struct tcpiphdr *);
|
| 534 |
|
|
if (tp->t_template == 0)
|
| 535 |
|
|
panic("tcp_output");
|
| 536 |
|
|
(void)memcpy(ti, tp->t_template, sizeof (struct tcpiphdr));
|
| 537 |
|
|
|
| 538 |
|
|
/*
|
| 539 |
|
|
* Fill in fields, remembering maximum advertised
|
| 540 |
|
|
* window for use in delaying messages about window sizes.
|
| 541 |
|
|
* If resending a FIN, be sure not to use a new sequence number.
|
| 542 |
|
|
*/
|
| 543 |
|
|
if (flags & TH_FIN && tp->t_flags & TF_SENTFIN &&
|
| 544 |
|
|
tp->snd_nxt == tp->snd_max)
|
| 545 |
|
|
tp->snd_nxt--;
|
| 546 |
|
|
/*
|
| 547 |
|
|
* If we are doing retransmissions, then snd_nxt will
|
| 548 |
|
|
* not reflect the first unsent octet. For ACK only
|
| 549 |
|
|
* packets, we do not want the sequence number of the
|
| 550 |
|
|
* retransmitted packet, we want the sequence number
|
| 551 |
|
|
* of the next unsent octet. So, if there is no data
|
| 552 |
|
|
* (and no SYN or FIN), use snd_max instead of snd_nxt
|
| 553 |
|
|
* when filling in ti_seq. But if we are in persist
|
| 554 |
|
|
* state, snd_max might reflect one byte beyond the
|
| 555 |
|
|
* right edge of the window, so use snd_nxt in that
|
| 556 |
|
|
* case, since we know we aren't doing a retransmission.
|
| 557 |
|
|
* (retransmit and persist are mutually exclusive...)
|
| 558 |
|
|
*/
|
| 559 |
|
|
if (len || (flags & (TH_SYN|TH_FIN)) || tp->t_timer[TCPT_PERSIST])
|
| 560 |
|
|
ti->ti_seq = htonl(tp->snd_nxt);
|
| 561 |
|
|
else
|
| 562 |
|
|
ti->ti_seq = htonl(tp->snd_max);
|
| 563 |
|
|
ti->ti_ack = htonl(tp->rcv_nxt);
|
| 564 |
|
|
if (optlen) {
|
| 565 |
|
|
bcopy(opt, ti + 1, optlen);
|
| 566 |
|
|
ti->ti_off = (sizeof (struct tcphdr) + optlen) >> 2;
|
| 567 |
|
|
}
|
| 568 |
|
|
ti->ti_flags = flags;
|
| 569 |
|
|
/*
|
| 570 |
|
|
* Calculate receive window. Don't shrink window,
|
| 571 |
|
|
* but avoid silly window syndrome.
|
| 572 |
|
|
*/
|
| 573 |
|
|
if (win < (long)(so->so_rcv.sb_hiwat / 4) && win < (long)tp->t_maxseg)
|
| 574 |
|
|
win = 0;
|
| 575 |
|
|
if (win < (long)(tp->rcv_adv - tp->rcv_nxt))
|
| 576 |
|
|
win = (long)(tp->rcv_adv - tp->rcv_nxt);
|
| 577 |
|
|
if (win > (long)TCP_MAXWIN << tp->rcv_scale)
|
| 578 |
|
|
win = (long)TCP_MAXWIN << tp->rcv_scale;
|
| 579 |
|
|
ti->ti_win = htons((u_short) (win>>tp->rcv_scale));
|
| 580 |
|
|
if (SEQ_GT(tp->snd_up, tp->snd_nxt)) {
|
| 581 |
|
|
ti->ti_urp = htons((u_short)(tp->snd_up - tp->snd_nxt));
|
| 582 |
|
|
ti->ti_flags |= TH_URG;
|
| 583 |
|
|
} else
|
| 584 |
|
|
/*
|
| 585 |
|
|
* If no urgent pointer to send, then we pull
|
| 586 |
|
|
* the urgent pointer to the left edge of the send window
|
| 587 |
|
|
* so that it doesn't drift into the send window on sequence
|
| 588 |
|
|
* number wraparound.
|
| 589 |
|
|
*/
|
| 590 |
|
|
tp->snd_up = tp->snd_una; /* drag it along */
|
| 591 |
|
|
|
| 592 |
|
|
/*
|
| 593 |
|
|
* Put TCP length in extended header, and then
|
| 594 |
|
|
* checksum extended header and data.
|
| 595 |
|
|
*/
|
| 596 |
|
|
if (len + optlen)
|
| 597 |
|
|
ti->ti_len = htons((u_short)(sizeof (struct tcphdr) +
|
| 598 |
|
|
optlen + len));
|
| 599 |
|
|
ti->ti_sum = in_cksum(m, (int)(hdrlen + len));
|
| 600 |
|
|
|
| 601 |
|
|
/*
|
| 602 |
|
|
* In transmit state, time the transmission and arrange for
|
| 603 |
|
|
* the retransmit. In persist state, just set snd_max.
|
| 604 |
|
|
*/
|
| 605 |
|
|
if (tp->t_force == 0 || tp->t_timer[TCPT_PERSIST] == 0) {
|
| 606 |
|
|
tcp_seq startseq = tp->snd_nxt;
|
| 607 |
|
|
|
| 608 |
|
|
/*
|
| 609 |
|
|
* Advance snd_nxt over sequence space of this segment.
|
| 610 |
|
|
*/
|
| 611 |
|
|
if (flags & (TH_SYN|TH_FIN)) {
|
| 612 |
|
|
if (flags & TH_SYN)
|
| 613 |
|
|
tp->snd_nxt++;
|
| 614 |
|
|
if (flags & TH_FIN) {
|
| 615 |
|
|
tp->snd_nxt++;
|
| 616 |
|
|
tp->t_flags |= TF_SENTFIN;
|
| 617 |
|
|
}
|
| 618 |
|
|
}
|
| 619 |
|
|
tp->snd_nxt += len;
|
| 620 |
|
|
if (SEQ_GT(tp->snd_nxt, tp->snd_max)) {
|
| 621 |
|
|
tp->snd_max = tp->snd_nxt;
|
| 622 |
|
|
/*
|
| 623 |
|
|
* Time this transmission if not a retransmission and
|
| 624 |
|
|
* not currently timing anything.
|
| 625 |
|
|
*/
|
| 626 |
|
|
if (tp->t_rtt == 0) {
|
| 627 |
|
|
tp->t_rtt = 1;
|
| 628 |
|
|
tp->t_rtseq = startseq;
|
| 629 |
|
|
tcpstat.tcps_segstimed++;
|
| 630 |
|
|
}
|
| 631 |
|
|
}
|
| 632 |
|
|
|
| 633 |
|
|
/*
|
| 634 |
|
|
* Set retransmit timer if not currently set,
|
| 635 |
|
|
* and not doing an ack or a keep-alive probe.
|
| 636 |
|
|
* Initial value for retransmit timer is smoothed
|
| 637 |
|
|
* round-trip time + 2 * round-trip time variance.
|
| 638 |
|
|
* Initialize shift counter which is used for backoff
|
| 639 |
|
|
* of retransmit time.
|
| 640 |
|
|
*/
|
| 641 |
|
|
if (tp->t_timer[TCPT_REXMT] == 0 &&
|
| 642 |
|
|
tp->snd_nxt != tp->snd_una) {
|
| 643 |
|
|
tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
|
| 644 |
|
|
if (tp->t_timer[TCPT_PERSIST]) {
|
| 645 |
|
|
tp->t_timer[TCPT_PERSIST] = 0;
|
| 646 |
|
|
tp->t_rxtshift = 0;
|
| 647 |
|
|
}
|
| 648 |
|
|
}
|
| 649 |
|
|
} else
|
| 650 |
|
|
if (SEQ_GT(tp->snd_nxt + len, tp->snd_max))
|
| 651 |
|
|
tp->snd_max = tp->snd_nxt + len;
|
| 652 |
|
|
|
| 653 |
|
|
#ifdef TCPDEBUG
|
| 654 |
|
|
/*
|
| 655 |
|
|
* Trace.
|
| 656 |
|
|
*/
|
| 657 |
|
|
if (so->so_options & SO_DEBUG)
|
| 658 |
|
|
tcp_trace(TA_OUTPUT, tp->t_state, tp, ti, 0);
|
| 659 |
|
|
#endif
|
| 660 |
|
|
|
| 661 |
|
|
/*
|
| 662 |
|
|
* Fill in IP length and desired time to live and
|
| 663 |
|
|
* send to IP level. There should be a better way
|
| 664 |
|
|
* to handle ttl and tos; we could keep them in
|
| 665 |
|
|
* the template, but need a way to checksum without them.
|
| 666 |
|
|
*/
|
| 667 |
|
|
m->m_pkthdr.len = hdrlen + len;
|
| 668 |
|
|
#ifdef TUBA
|
| 669 |
|
|
if (tp->t_tuba_pcb)
|
| 670 |
|
|
error = tuba_output(m, tp);
|
| 671 |
|
|
else
|
| 672 |
|
|
#endif
|
| 673 |
|
|
{
|
| 674 |
|
|
#if 1
|
| 675 |
|
|
struct rtentry *rt;
|
| 676 |
|
|
#endif
|
| 677 |
|
|
((struct ip *)ti)->ip_len = m->m_pkthdr.len;
|
| 678 |
|
|
((struct ip *)ti)->ip_ttl = tp->t_inpcb->inp_ip_ttl; /* XXX */
|
| 679 |
|
|
((struct ip *)ti)->ip_tos = tp->t_inpcb->inp_ip_tos; /* XXX */
|
| 680 |
|
|
#if 1
|
| 681 |
|
|
/*
|
| 682 |
|
|
* See if we should do MTU discovery. We do it only if the following
|
| 683 |
|
|
* are true:
|
| 684 |
|
|
* 1) we have a valid route to the destination
|
| 685 |
|
|
* 2) the MTU is not locked (if it is, then discovery has been
|
| 686 |
|
|
* disabled)
|
| 687 |
|
|
*/
|
| 688 |
|
|
if ((rt = tp->t_inpcb->inp_route.ro_rt)
|
| 689 |
|
|
&& rt->rt_flags & RTF_UP
|
| 690 |
|
|
&& !(rt->rt_rmx.rmx_locks & RTV_MTU)) {
|
| 691 |
|
|
((struct ip *)ti)->ip_off |= IP_DF;
|
| 692 |
|
|
}
|
| 693 |
|
|
#endif
|
| 694 |
|
|
error = ip_output(m, tp->t_inpcb->inp_options, &tp->t_inpcb->inp_route,
|
| 695 |
|
|
so->so_options & SO_DONTROUTE, 0);
|
| 696 |
|
|
}
|
| 697 |
|
|
if (error) {
|
| 698 |
|
|
out:
|
| 699 |
|
|
if (error == ENOBUFS) {
|
| 700 |
|
|
tcp_quench(tp->t_inpcb, 0);
|
| 701 |
|
|
return (0);
|
| 702 |
|
|
}
|
| 703 |
|
|
#if 1
|
| 704 |
|
|
if (error == EMSGSIZE) {
|
| 705 |
|
|
/*
|
| 706 |
|
|
* ip_output() will have already fixed the route
|
| 707 |
|
|
* for us. tcp_mtudisc() will, as its last action,
|
| 708 |
|
|
* initiate retransmission, so it is important to
|
| 709 |
|
|
* not do so here.
|
| 710 |
|
|
*/
|
| 711 |
|
|
tcp_mtudisc(tp->t_inpcb, 0);
|
| 712 |
|
|
return 0;
|
| 713 |
|
|
}
|
| 714 |
|
|
#endif
|
| 715 |
|
|
if ((error == EHOSTUNREACH || error == ENETDOWN)
|
| 716 |
|
|
&& TCPS_HAVERCVDSYN(tp->t_state)) {
|
| 717 |
|
|
tp->t_softerror = error;
|
| 718 |
|
|
return (0);
|
| 719 |
|
|
}
|
| 720 |
|
|
return (error);
|
| 721 |
|
|
}
|
| 722 |
|
|
tcpstat.tcps_sndtotal++;
|
| 723 |
|
|
|
| 724 |
|
|
/*
|
| 725 |
|
|
* Data sent (as far as we can tell).
|
| 726 |
|
|
* If this advertises a larger window than any other segment,
|
| 727 |
|
|
* then remember the size of the advertised window.
|
| 728 |
|
|
* Any pending ACK has now been sent.
|
| 729 |
|
|
*/
|
| 730 |
|
|
if (win > 0 && SEQ_GT(tp->rcv_nxt+win, tp->rcv_adv))
|
| 731 |
|
|
tp->rcv_adv = tp->rcv_nxt + win;
|
| 732 |
|
|
tp->last_ack_sent = tp->rcv_nxt;
|
| 733 |
|
|
tp->t_flags &= ~(TF_ACKNOW|TF_DELACK);
|
| 734 |
|
|
if (sendalot)
|
| 735 |
|
|
goto again;
|
| 736 |
|
|
return (0);
|
| 737 |
|
|
}
|
| 738 |
|
|
|
| 739 |
|
|
void
|
| 740 |
|
|
tcp_setpersist(tp)
|
| 741 |
|
|
register struct tcpcb *tp;
|
| 742 |
|
|
{
|
| 743 |
|
|
register int t = ((tp->t_srtt >> 2) + tp->t_rttvar) >> 1;
|
| 744 |
|
|
|
| 745 |
|
|
if (tp->t_timer[TCPT_REXMT])
|
| 746 |
|
|
panic("tcp_output REXMT");
|
| 747 |
|
|
/*
|
| 748 |
|
|
* Start/restart persistance timer.
|
| 749 |
|
|
*/
|
| 750 |
|
|
TCPT_RANGESET(tp->t_timer[TCPT_PERSIST],
|
| 751 |
|
|
t * tcp_backoff[tp->t_rxtshift],
|
| 752 |
|
|
TCPTV_PERSMIN, TCPTV_PERSMAX);
|
| 753 |
|
|
if (tp->t_rxtshift < TCP_MAXRXTSHIFT)
|
| 754 |
|
|
tp->t_rxtshift++;
|
| 755 |
|
|
}
|
