1400 lines
38 KiB
C
1400 lines
38 KiB
C
/* $OpenBSD: tcp_output.c,v 1.145 2024/05/14 09:39:02 bluhm Exp $ */
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/* $NetBSD: tcp_output.c,v 1.16 1997/06/03 16:17:09 kml Exp $ */
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/*
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* Copyright (c) 1982, 1986, 1988, 1990, 1993
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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. 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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* @(#)COPYRIGHT 1.1 (NRL) 17 January 1995
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*
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* NRL grants permission for redistribution and use in source and binary
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* forms, with or without modification, of the software and documentation
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* created at NRL provided that the following conditions are met:
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*
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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 acknowledgements:
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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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* This product includes software developed at the Information
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* Technology Division, US Naval Research Laboratory.
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* 4. Neither the name of the NRL 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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* THE SOFTWARE PROVIDED BY NRL IS PROVIDED BY NRL AND CONTRIBUTORS ``AS
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* IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL NRL OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* The views and conclusions contained in the software and documentation
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* are those of the authors and should not be interpreted as representing
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* official policies, either expressed or implied, of the US Naval
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* Research Laboratory (NRL).
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*/
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#include "pf.h"
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#include "stoeplitz.h"
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#include <sys/param.h>
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#include <sys/systm.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/kernel.h>
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#include <net/if.h>
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#include <net/if_var.h>
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#include <net/route.h>
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#if NPF > 0
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#include <net/pfvar.h>
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#endif
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#include <netinet/in.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 <netinet6/ip6_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/tcp_debug.h>
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#ifdef notyet
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extern struct mbuf *m_copypack();
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#endif
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extern int tcprexmtthresh;
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#ifdef TCP_SACK_DEBUG
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void tcp_print_holes(struct tcpcb *tp);
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void
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tcp_print_holes(struct tcpcb *tp)
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{
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struct sackhole *p = tp->snd_holes;
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if (p == NULL)
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return;
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printf("Hole report: start--end dups rxmit\n");
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while (p) {
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printf("%x--%x d %d r %x\n", p->start, p->end, p->dups,
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p->rxmit);
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p = p->next;
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}
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printf("\n");
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}
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#endif /* TCP_SACK_DEBUG */
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/*
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* Returns pointer to a sackhole if there are any pending retransmissions;
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* NULL otherwise.
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*/
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struct sackhole *
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tcp_sack_output(struct tcpcb *tp)
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{
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struct sackhole *p;
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if (!tp->sack_enable)
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return (NULL);
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p = tp->snd_holes;
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while (p) {
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if (p->dups >= tcprexmtthresh && SEQ_LT(p->rxmit, p->end)) {
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if (SEQ_LT(p->rxmit, tp->snd_una)) {/* old SACK hole */
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p = p->next;
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continue;
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}
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#ifdef TCP_SACK_DEBUG
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if (p)
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tcp_print_holes(tp);
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#endif
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return (p);
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}
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p = p->next;
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}
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return (NULL);
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}
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/*
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* After a timeout, the SACK list may be rebuilt. This SACK information
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* should be used to avoid retransmitting SACKed data. This function
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* traverses the SACK list to see if snd_nxt should be moved forward.
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*/
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void
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tcp_sack_adjust(struct tcpcb *tp)
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{
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struct sackhole *cur = tp->snd_holes;
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if (cur == NULL)
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return; /* No holes */
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if (SEQ_GEQ(tp->snd_nxt, tp->rcv_lastsack))
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return; /* We're already beyond any SACKed blocks */
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/*
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* Two cases for which we want to advance snd_nxt:
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* i) snd_nxt lies between end of one hole and beginning of another
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* ii) snd_nxt lies between end of last hole and rcv_lastsack
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*/
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while (cur->next) {
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if (SEQ_LT(tp->snd_nxt, cur->end))
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return;
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if (SEQ_GEQ(tp->snd_nxt, cur->next->start))
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cur = cur->next;
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else {
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tp->snd_nxt = cur->next->start;
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return;
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}
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}
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if (SEQ_LT(tp->snd_nxt, cur->end))
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return;
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tp->snd_nxt = tp->rcv_lastsack;
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return;
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}
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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(struct tcpcb *tp)
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{
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struct socket *so = tp->t_inpcb->inp_socket;
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long len, win, txmaxseg;
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int off, flags, error;
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struct mbuf *m;
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struct tcphdr *th;
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u_int32_t optbuf[howmany(MAX_TCPOPTLEN, sizeof(u_int32_t))];
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u_char *opt = (u_char *)optbuf;
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unsigned int optlen, hdrlen, packetlen;
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int idle, sendalot = 0;
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int i, sack_rxmit = 0;
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struct sackhole *p;
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uint64_t now;
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#ifdef TCP_SIGNATURE
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unsigned int sigoff;
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#endif /* TCP_SIGNATURE */
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#ifdef TCP_ECN
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int needect;
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#endif
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int tso;
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if (tp->t_flags & TF_BLOCKOUTPUT) {
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tp->t_flags |= TF_NEEDOUTPUT;
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return (0);
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} else
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tp->t_flags &= ~TF_NEEDOUTPUT;
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#if defined(TCP_SIGNATURE) && defined(DIAGNOSTIC)
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if (tp->sack_enable && (tp->t_flags & TF_SIGNATURE))
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return (EINVAL);
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#endif /* defined(TCP_SIGNATURE) && defined(DIAGNOSTIC) */
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now = tcp_now();
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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->t_flags & TF_LASTIDLE) || (tp->snd_max == tp->snd_una);
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if (idle && (now - tp->t_rcvtime) >= 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 = 2 * tp->t_maxseg;
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/* remember 'idle' for next invocation of tcp_output */
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if (idle && soissending(so)) {
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tp->t_flags |= TF_LASTIDLE;
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idle = 0;
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} else
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tp->t_flags &= ~TF_LASTIDLE;
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again:
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/*
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* If we've recently taken a timeout, snd_max will be greater than
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* snd_nxt. There may be SACK information that allows us to avoid
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* resending already delivered data. Adjust snd_nxt accordingly.
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*/
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if (tp->sack_enable && SEQ_LT(tp->snd_nxt, tp->snd_max))
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tcp_sack_adjust(tp);
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off = tp->snd_nxt - tp->snd_una;
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win = ulmin(tp->snd_wnd, tp->snd_cwnd);
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flags = tcp_outflags[tp->t_state];
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/*
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* Send any SACK-generated retransmissions. If we're explicitly trying
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* to send out new data (when sendalot is 1), bypass this function.
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* If we retransmit in fast recovery mode, decrement snd_cwnd, since
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* we're replacing a (future) new transmission with a retransmission
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* now, and we previously incremented snd_cwnd in tcp_input().
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*/
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if (tp->sack_enable && !sendalot) {
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if (tp->t_dupacks >= tcprexmtthresh &&
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(p = tcp_sack_output(tp))) {
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off = p->rxmit - tp->snd_una;
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sack_rxmit = 1;
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/* Coalesce holes into a single retransmission */
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len = min(tp->t_maxseg, p->end - p->rxmit);
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if (SEQ_LT(tp->snd_una, tp->snd_last))
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tp->snd_cwnd -= tp->t_maxseg;
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}
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}
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sendalot = 0;
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tso = 0;
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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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TCP_TIMER_DISARM(tp, TCPT_PERSIST);
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tp->t_rxtshift = 0;
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}
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}
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if (!sack_rxmit) {
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len = ulmin(so->so_snd.sb_cc, win) - off;
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}
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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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TCP_TIMER_DISARM(tp, TCPT_REXMT);
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tp->t_rxtshift = 0;
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tp->snd_nxt = tp->snd_una;
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if (TCP_TIMER_ISARMED(tp, TCPT_PERSIST) == 0)
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tcp_setpersist(tp);
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}
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}
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/*
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* Never send more than half a buffer full. This insures that we can
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* always keep 2 packets on the wire, no matter what SO_SNDBUF is, and
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* therefore acks will never be delayed unless we run out of data to
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* transmit.
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*/
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txmaxseg = ulmin(so->so_snd.sb_hiwat / 2, tp->t_maxseg);
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if (len > txmaxseg) {
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if (tcp_do_tso &&
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tp->t_inpcb->inp_options == NULL &&
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tp->t_inpcb->inp_outputopts6 == NULL &&
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#ifdef TCP_SIGNATURE
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((tp->t_flags & TF_SIGNATURE) == 0) &&
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#endif
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len >= 2 * tp->t_maxseg &&
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tp->rcv_numsacks == 0 && sack_rxmit == 0 &&
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!(flags & (TH_SYN|TH_RST|TH_FIN))) {
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tso = 1;
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/* avoid small chopped packets */
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if (len > (len / tp->t_maxseg) * tp->t_maxseg) {
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len = (len / tp->t_maxseg) * tp->t_maxseg;
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sendalot = 1;
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}
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} else {
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len = txmaxseg;
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sendalot = 1;
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}
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}
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if (off + len < so->so_snd.sb_cc)
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flags &= ~TH_FIN;
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win = sbspace(so, &so->so_rcv);
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/*
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* Sender silly window avoidance. If connection is idle
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* and can send all data, a maximum segment,
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* at least a maximum default-size segment do it,
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* or are forced, do it; otherwise don't bother.
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* If peer's buffer is tiny, then send
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* when window is at least half open.
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* If retransmitting (possibly after persist timer forced us
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* to send into a small window), then must resend.
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*/
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if (len) {
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if (len >= txmaxseg)
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goto send;
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if ((idle || (tp->t_flags & TF_NODELAY)) &&
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len + off >= so->so_snd.sb_cc && !soissending(so) &&
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(tp->t_flags & TF_NOPUSH) == 0)
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goto send;
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if (tp->t_force)
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goto send;
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if (len >= tp->max_sndwnd / 2 && tp->max_sndwnd > 0)
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goto send;
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if (SEQ_LT(tp->snd_nxt, tp->snd_max))
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goto send;
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if (sack_rxmit)
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goto send;
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}
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|
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/*
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* Compare available window to amount of window
|
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* known to peer (as advertised window less
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* next expected input). If the difference is at least two
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* max size segments, or at least 50% of the maximum possible
|
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* window, then want to send a window update to peer.
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*/
|
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if (win > 0) {
|
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/*
|
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* "adv" is the amount we can increase the window,
|
|
* taking into account that we are limited by
|
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* TCP_MAXWIN << tp->rcv_scale.
|
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*/
|
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long adv = lmin(win, (long)TCP_MAXWIN << tp->rcv_scale) -
|
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(tp->rcv_adv - tp->rcv_nxt);
|
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|
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if (adv >= (long) (2 * tp->t_maxseg))
|
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goto send;
|
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if (2 * adv >= (long) so->so_rcv.sb_hiwat)
|
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goto send;
|
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}
|
|
|
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/*
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* Send if we owe peer an ACK.
|
|
*/
|
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if (tp->t_flags & TF_ACKNOW)
|
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goto send;
|
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if (flags & (TH_SYN|TH_RST))
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goto send;
|
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if (SEQ_GT(tp->snd_up, tp->snd_una))
|
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goto send;
|
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/*
|
|
* 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.
|
|
*/
|
|
if (flags & TH_FIN &&
|
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((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 (SEQ_GT(tp->snd_max, tp->snd_una) &&
|
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TCP_TIMER_ISARMED(tp, TCPT_REXMT) == 0 &&
|
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TCP_TIMER_ISARMED(tp, TCPT_PERSIST) == 0) {
|
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TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur);
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|
return (0);
|
|
}
|
|
|
|
/*
|
|
* TCP window updates are not reliable, rather a polling protocol
|
|
* using ``persist'' packets is used to insure receipt of window
|
|
* updates. The three ``states'' for the output side are:
|
|
* idle not doing retransmits or persists
|
|
* persisting to move a small or zero window
|
|
* (re)transmitting and thereby not persisting
|
|
*
|
|
* tp->t_timer[TCPT_PERSIST]
|
|
* is set when we are in persist state.
|
|
* tp->t_force
|
|
* is set when we are called to send a persist packet.
|
|
* tp->t_timer[TCPT_REXMT]
|
|
* is set when we are retransmitting
|
|
* The output side is idle when both timers are zero.
|
|
*
|
|
* If send window is too small, there is data to transmit, and no
|
|
* retransmit or persist is pending, then go to persist state.
|
|
* If nothing happens soon, send when timer expires:
|
|
* if window is nonzero, transmit what we can,
|
|
* otherwise force out a byte.
|
|
*/
|
|
if (so->so_snd.sb_cc && TCP_TIMER_ISARMED(tp, TCPT_REXMT) == 0 &&
|
|
TCP_TIMER_ISARMED(tp, TCPT_PERSIST) == 0) {
|
|
tp->t_rxtshift = 0;
|
|
tcp_setpersist(tp);
|
|
}
|
|
|
|
/*
|
|
* No reason to send a segment, just return.
|
|
*/
|
|
return (0);
|
|
|
|
send:
|
|
/*
|
|
* Before ESTABLISHED, force sending of initial options
|
|
* unless TCP set not to do any options.
|
|
* NOTE: we assume that the IP/TCP header plus TCP options
|
|
* always fit in a single mbuf, leaving room for a maximum
|
|
* link header, i.e.
|
|
* max_linkhdr + sizeof(network header) + sizeof(struct tcphdr +
|
|
* optlen <= MHLEN
|
|
*/
|
|
optlen = 0;
|
|
|
|
switch (tp->pf) {
|
|
case 0: /*default to PF_INET*/
|
|
case PF_INET:
|
|
hdrlen = sizeof(struct ip) + sizeof(struct tcphdr);
|
|
break;
|
|
#ifdef INET6
|
|
case PF_INET6:
|
|
hdrlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
|
|
break;
|
|
#endif /* INET6 */
|
|
default:
|
|
return (EPFNOSUPPORT);
|
|
}
|
|
|
|
if (flags & TH_SYN) {
|
|
tp->snd_nxt = tp->iss;
|
|
if ((tp->t_flags & TF_NOOPT) == 0) {
|
|
u_int16_t mss;
|
|
|
|
opt[0] = TCPOPT_MAXSEG;
|
|
opt[1] = 4;
|
|
mss = htons((u_int16_t) tcp_mss(tp, 0));
|
|
memcpy(opt + 2, &mss, sizeof(mss));
|
|
optlen = 4;
|
|
|
|
if (flags & TH_ACK)
|
|
tcp_mss_update(tp);
|
|
/*
|
|
* If this is the first SYN of connection (not a SYN
|
|
* ACK), include SACK_PERMIT_HDR option. If this is a
|
|
* SYN ACK, include SACK_PERMIT_HDR option if peer has
|
|
* already done so.
|
|
*/
|
|
if (tp->sack_enable && ((flags & TH_ACK) == 0 ||
|
|
(tp->t_flags & TF_SACK_PERMIT))) {
|
|
*((u_int32_t *) (opt + optlen)) =
|
|
htonl(TCPOPT_SACK_PERMIT_HDR);
|
|
optlen += 4;
|
|
}
|
|
if ((tp->t_flags & TF_REQ_SCALE) &&
|
|
((flags & TH_ACK) == 0 ||
|
|
(tp->t_flags & TF_RCVD_SCALE))) {
|
|
*((u_int32_t *) (opt + optlen)) = htonl(
|
|
TCPOPT_NOP << 24 |
|
|
TCPOPT_WINDOW << 16 |
|
|
TCPOLEN_WINDOW << 8 |
|
|
tp->request_r_scale);
|
|
optlen += 4;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Send a timestamp and echo-reply if this is a SYN and our side
|
|
* wants to use timestamps (TF_REQ_TSTMP is set) or both our side
|
|
* and our peer have sent timestamps in our SYN's.
|
|
*/
|
|
if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP &&
|
|
(flags & TH_RST) == 0 &&
|
|
((flags & (TH_SYN|TH_ACK)) == TH_SYN ||
|
|
(tp->t_flags & TF_RCVD_TSTMP))) {
|
|
u_int32_t *lp = (u_int32_t *)(opt + optlen);
|
|
|
|
/* Form timestamp option as shown in appendix A of RFC 1323. */
|
|
*lp++ = htonl(TCPOPT_TSTAMP_HDR);
|
|
*lp++ = htonl(now + tp->ts_modulate);
|
|
*lp = htonl(tp->ts_recent);
|
|
optlen += TCPOLEN_TSTAMP_APPA;
|
|
}
|
|
/* Set receive buffer autosizing timestamp. */
|
|
if (tp->rfbuf_ts == 0) {
|
|
tp->rfbuf_ts = now;
|
|
tp->rfbuf_cnt = 0;
|
|
}
|
|
|
|
#ifdef TCP_SIGNATURE
|
|
if (tp->t_flags & TF_SIGNATURE) {
|
|
u_int8_t *bp = (u_int8_t *)(opt + optlen);
|
|
|
|
/* Send signature option */
|
|
*(bp++) = TCPOPT_SIGNATURE;
|
|
*(bp++) = TCPOLEN_SIGNATURE;
|
|
sigoff = optlen + 2;
|
|
|
|
{
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < 16; i++)
|
|
*(bp++) = 0;
|
|
}
|
|
|
|
|
|
/* Pad options list to the next 32 bit boundary and
|
|
* terminate it.
|
|
*/
|
|
*bp++ = TCPOPT_NOP;
|
|
*bp++ = TCPOPT_NOP;
|
|
|
|
optlen += TCPOLEN_SIGLEN;
|
|
}
|
|
#endif /* TCP_SIGNATURE */
|
|
|
|
/*
|
|
* 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. No more than three SACKs are sent.
|
|
*/
|
|
if (tp->sack_enable && tp->t_state == TCPS_ESTABLISHED &&
|
|
(tp->t_flags & (TF_SACK_PERMIT|TF_NOOPT)) == TF_SACK_PERMIT &&
|
|
tp->rcv_numsacks) {
|
|
u_int32_t *lp = (u_int32_t *)(opt + optlen);
|
|
u_int32_t *olp = lp++;
|
|
int count = 0; /* actual number of SACKs inserted */
|
|
int maxsack = (MAX_TCPOPTLEN - (optlen + 4))/TCPOLEN_SACK;
|
|
|
|
tcpstat_inc(tcps_sack_snd_opts);
|
|
maxsack = min(maxsack, TCP_MAX_SACK);
|
|
for (i = 0; (i < tp->rcv_numsacks && count < maxsack); i++) {
|
|
struct sackblk sack = tp->sackblks[i];
|
|
if (sack.start == 0 && sack.end == 0)
|
|
continue;
|
|
*lp++ = htonl(sack.start);
|
|
*lp++ = htonl(sack.end);
|
|
count++;
|
|
}
|
|
*olp = htonl(TCPOPT_SACK_HDR|(TCPOLEN_SACK*count+2));
|
|
optlen += TCPOLEN_SACK*count + 4; /* including leading NOPs */
|
|
}
|
|
|
|
#ifdef DIAGNOSTIC
|
|
if (optlen > MAX_TCPOPTLEN)
|
|
panic("tcp_output: options too long");
|
|
#endif /* DIAGNOSTIC */
|
|
|
|
hdrlen += optlen;
|
|
|
|
/*
|
|
* Adjust data length if insertion of options will
|
|
* bump the packet length beyond the t_maxopd length.
|
|
* Clear the FIN bit because we cut off the tail of
|
|
* the segment.
|
|
*/
|
|
if (len > tp->t_maxopd - optlen) {
|
|
if (tso) {
|
|
if (len + hdrlen + max_linkhdr > MAXMCLBYTES) {
|
|
len = MAXMCLBYTES - hdrlen - max_linkhdr;
|
|
sendalot = 1;
|
|
}
|
|
} else {
|
|
len = tp->t_maxopd - optlen;
|
|
sendalot = 1;
|
|
}
|
|
flags &= ~TH_FIN;
|
|
}
|
|
|
|
#ifdef DIAGNOSTIC
|
|
if (max_linkhdr + hdrlen > MCLBYTES)
|
|
panic("tcphdr too big");
|
|
#endif
|
|
|
|
/*
|
|
* Grab a header mbuf, attaching a copy of data to
|
|
* be transmitted, and initialize the header from
|
|
* the template for sends on this connection.
|
|
*/
|
|
if (len) {
|
|
if (tp->t_force && len == 1)
|
|
tcpstat_inc(tcps_sndprobe);
|
|
else if (SEQ_LT(tp->snd_nxt, tp->snd_max)) {
|
|
tcpstat_pkt(tcps_sndrexmitpack, tcps_sndrexmitbyte,
|
|
len);
|
|
tp->t_sndrexmitpack++;
|
|
} else {
|
|
tcpstat_pkt(tcps_sndpack, tcps_sndbyte, len);
|
|
}
|
|
#ifdef notyet
|
|
if ((m = m_copypack(so->so_snd.sb_mb, off,
|
|
(int)len, max_linkhdr + hdrlen)) == 0) {
|
|
error = ENOBUFS;
|
|
goto out;
|
|
}
|
|
/*
|
|
* m_copypack left space for our hdr; use it.
|
|
*/
|
|
m->m_len += hdrlen;
|
|
m->m_data -= hdrlen;
|
|
#else
|
|
MGETHDR(m, M_DONTWAIT, MT_HEADER);
|
|
if (m != NULL && max_linkhdr + hdrlen > MHLEN) {
|
|
MCLGET(m, M_DONTWAIT);
|
|
if ((m->m_flags & M_EXT) == 0) {
|
|
m_freem(m);
|
|
m = NULL;
|
|
}
|
|
}
|
|
if (m == NULL) {
|
|
error = ENOBUFS;
|
|
goto out;
|
|
}
|
|
m->m_data += max_linkhdr;
|
|
m->m_len = hdrlen;
|
|
if (len <= m_trailingspace(m)) {
|
|
m_copydata(so->so_snd.sb_mb, off, (int) len,
|
|
mtod(m, caddr_t) + hdrlen);
|
|
m->m_len += len;
|
|
} else {
|
|
m->m_next = m_copym(so->so_snd.sb_mb, off, (int) len,
|
|
M_NOWAIT);
|
|
if (m->m_next == 0) {
|
|
(void) m_free(m);
|
|
error = ENOBUFS;
|
|
goto out;
|
|
}
|
|
}
|
|
if (so->so_snd.sb_mb->m_flags & M_PKTHDR)
|
|
m->m_pkthdr.ph_loopcnt =
|
|
so->so_snd.sb_mb->m_pkthdr.ph_loopcnt;
|
|
#endif
|
|
/*
|
|
* If we're sending everything we've got, set PUSH.
|
|
* (This will keep happy those implementations which only
|
|
* give data to the user when a buffer fills or
|
|
* a PUSH comes in.)
|
|
*/
|
|
if (off + len == so->so_snd.sb_cc && !soissending(so))
|
|
flags |= TH_PUSH;
|
|
tp->t_sndtime = now;
|
|
} else {
|
|
if (tp->t_flags & TF_ACKNOW)
|
|
tcpstat_inc(tcps_sndacks);
|
|
else if (flags & (TH_SYN|TH_FIN|TH_RST))
|
|
tcpstat_inc(tcps_sndctrl);
|
|
else if (SEQ_GT(tp->snd_up, tp->snd_una))
|
|
tcpstat_inc(tcps_sndurg);
|
|
else
|
|
tcpstat_inc(tcps_sndwinup);
|
|
|
|
MGETHDR(m, M_DONTWAIT, MT_HEADER);
|
|
if (m != NULL && max_linkhdr + hdrlen > MHLEN) {
|
|
MCLGET(m, M_DONTWAIT);
|
|
if ((m->m_flags & M_EXT) == 0) {
|
|
m_freem(m);
|
|
m = NULL;
|
|
}
|
|
}
|
|
if (m == NULL) {
|
|
error = ENOBUFS;
|
|
goto out;
|
|
}
|
|
m->m_data += max_linkhdr;
|
|
m->m_len = hdrlen;
|
|
}
|
|
m->m_pkthdr.ph_ifidx = 0;
|
|
m->m_pkthdr.len = hdrlen + len;
|
|
|
|
/* Enable TSO and specify the size of the resulting segments. */
|
|
if (tso) {
|
|
SET(m->m_pkthdr.csum_flags, M_TCP_TSO);
|
|
m->m_pkthdr.ph_mss = tp->t_maxseg;
|
|
}
|
|
|
|
if (!tp->t_template)
|
|
panic("tcp_output");
|
|
#ifdef DIAGNOSTIC
|
|
if (tp->t_template->m_len != hdrlen - optlen)
|
|
panic("tcp_output: template len != hdrlen - optlen");
|
|
#endif /* DIAGNOSTIC */
|
|
memcpy(mtod(m, caddr_t), mtod(tp->t_template, caddr_t),
|
|
tp->t_template->m_len);
|
|
th = (struct tcphdr *)(mtod(m, caddr_t) + tp->t_template->m_len -
|
|
sizeof(struct tcphdr));
|
|
|
|
/*
|
|
* Fill in fields, remembering maximum advertised
|
|
* window for use in delaying messages about window sizes.
|
|
* If resending a FIN, be sure not to use a new sequence number.
|
|
*/
|
|
if ((flags & TH_FIN) && (tp->t_flags & TF_SENTFIN) &&
|
|
(tp->snd_nxt == tp->snd_max))
|
|
tp->snd_nxt--;
|
|
/*
|
|
* If we are doing retransmissions, then snd_nxt will
|
|
* not reflect the first unsent octet. For ACK only
|
|
* packets, we do not want the sequence number of the
|
|
* retransmitted packet, we want the sequence number
|
|
* of the next unsent octet. So, if there is no data
|
|
* (and no SYN or FIN), use snd_max instead of snd_nxt
|
|
* when filling in ti_seq. But if we are in persist
|
|
* state, snd_max might reflect one byte beyond the
|
|
* right edge of the window, so use snd_nxt in that
|
|
* case, since we know we aren't doing a retransmission.
|
|
* (retransmit and persist are mutually exclusive...)
|
|
*/
|
|
if (len || (flags & (TH_SYN|TH_FIN)) ||
|
|
TCP_TIMER_ISARMED(tp, TCPT_PERSIST))
|
|
th->th_seq = htonl(tp->snd_nxt);
|
|
else
|
|
th->th_seq = htonl(tp->snd_max);
|
|
|
|
if (sack_rxmit) {
|
|
/*
|
|
* If sendalot was turned on (due to option stuffing), turn it
|
|
* off. Properly set th_seq field. Advance the ret'x pointer
|
|
* by len.
|
|
*/
|
|
if (sendalot)
|
|
sendalot = 0;
|
|
th->th_seq = htonl(p->rxmit);
|
|
p->rxmit += len;
|
|
tcpstat_pkt(tcps_sack_rexmits, tcps_sack_rexmit_bytes, len);
|
|
}
|
|
|
|
th->th_ack = htonl(tp->rcv_nxt);
|
|
if (optlen) {
|
|
memcpy(th + 1, opt, optlen);
|
|
th->th_off = (sizeof (struct tcphdr) + optlen) >> 2;
|
|
}
|
|
#ifdef TCP_ECN
|
|
if (tcp_do_ecn) {
|
|
/*
|
|
* if we have received congestion experienced segs,
|
|
* set ECE bit.
|
|
*/
|
|
if (tp->t_flags & TF_RCVD_CE) {
|
|
flags |= TH_ECE;
|
|
tcpstat_inc(tcps_ecn_sndece);
|
|
}
|
|
if (!(tp->t_flags & TF_DISABLE_ECN)) {
|
|
/*
|
|
* if this is a SYN seg, set ECE and CWR.
|
|
* set only ECE for SYN-ACK if peer supports ECN.
|
|
*/
|
|
if ((flags & (TH_SYN|TH_ACK)) == TH_SYN)
|
|
flags |= (TH_ECE|TH_CWR);
|
|
else if ((tp->t_flags & TF_ECN_PERMIT) &&
|
|
(flags & (TH_SYN|TH_ACK)) == (TH_SYN|TH_ACK))
|
|
flags |= TH_ECE;
|
|
}
|
|
/*
|
|
* if we have reduced the congestion window, notify
|
|
* the peer by setting CWR bit.
|
|
*/
|
|
if ((tp->t_flags & TF_ECN_PERMIT) &&
|
|
(tp->t_flags & TF_SEND_CWR)) {
|
|
flags |= TH_CWR;
|
|
tp->t_flags &= ~TF_SEND_CWR;
|
|
tcpstat_inc(tcps_ecn_sndcwr);
|
|
}
|
|
}
|
|
#endif
|
|
th->th_flags = flags;
|
|
|
|
/*
|
|
* 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)TCP_MAXWIN << tp->rcv_scale)
|
|
win = (long)TCP_MAXWIN << tp->rcv_scale;
|
|
if (win < (long)(int32_t)(tp->rcv_adv - tp->rcv_nxt))
|
|
win = (long)(int32_t)(tp->rcv_adv - tp->rcv_nxt);
|
|
if (flags & TH_RST)
|
|
win = 0;
|
|
th->th_win = htons((u_int16_t) (win>>tp->rcv_scale));
|
|
if (th->th_win == 0)
|
|
tp->t_sndzerowin++;
|
|
if (SEQ_GT(tp->snd_up, tp->snd_nxt)) {
|
|
u_int32_t urp = tp->snd_up - tp->snd_nxt;
|
|
if (urp > IP_MAXPACKET)
|
|
urp = IP_MAXPACKET;
|
|
th->th_urp = htons((u_int16_t)urp);
|
|
th->th_flags |= TH_URG;
|
|
} else
|
|
/*
|
|
* If no urgent pointer to send, then we pull
|
|
* the urgent pointer to the left edge of the send window
|
|
* so that it doesn't drift into the send window on sequence
|
|
* number wraparound.
|
|
*/
|
|
tp->snd_up = tp->snd_una; /* drag it along */
|
|
|
|
#ifdef TCP_SIGNATURE
|
|
if (tp->t_flags & TF_SIGNATURE) {
|
|
int iphlen;
|
|
union sockaddr_union src, dst;
|
|
struct tdb *tdb;
|
|
|
|
bzero(&src, sizeof(union sockaddr_union));
|
|
bzero(&dst, sizeof(union sockaddr_union));
|
|
|
|
switch (tp->pf) {
|
|
case 0: /*default to PF_INET*/
|
|
case AF_INET:
|
|
iphlen = sizeof(struct ip);
|
|
src.sa.sa_len = sizeof(struct sockaddr_in);
|
|
src.sa.sa_family = AF_INET;
|
|
src.sin.sin_addr = mtod(m, struct ip *)->ip_src;
|
|
dst.sa.sa_len = sizeof(struct sockaddr_in);
|
|
dst.sa.sa_family = AF_INET;
|
|
dst.sin.sin_addr = mtod(m, struct ip *)->ip_dst;
|
|
break;
|
|
#ifdef INET6
|
|
case AF_INET6:
|
|
iphlen = sizeof(struct ip6_hdr);
|
|
src.sa.sa_len = sizeof(struct sockaddr_in6);
|
|
src.sa.sa_family = AF_INET6;
|
|
src.sin6.sin6_addr = mtod(m, struct ip6_hdr *)->ip6_src;
|
|
dst.sa.sa_len = sizeof(struct sockaddr_in6);
|
|
dst.sa.sa_family = AF_INET6;
|
|
dst.sin6.sin6_addr = mtod(m, struct ip6_hdr *)->ip6_dst;
|
|
break;
|
|
#endif /* INET6 */
|
|
}
|
|
|
|
tdb = gettdbbysrcdst(rtable_l2(tp->t_inpcb->inp_rtableid),
|
|
0, &src, &dst, IPPROTO_TCP);
|
|
if (tdb == NULL) {
|
|
m_freem(m);
|
|
return (EPERM);
|
|
}
|
|
|
|
if (tcp_signature(tdb, tp->pf, m, th, iphlen, 0,
|
|
mtod(m, caddr_t) + hdrlen - optlen + sigoff) < 0) {
|
|
m_freem(m);
|
|
tdb_unref(tdb);
|
|
return (EINVAL);
|
|
}
|
|
tdb_unref(tdb);
|
|
}
|
|
#endif /* TCP_SIGNATURE */
|
|
|
|
/* Defer checksumming until later (ip_output() or hardware) */
|
|
m->m_pkthdr.csum_flags |= M_TCP_CSUM_OUT;
|
|
|
|
/*
|
|
* In transmit state, time the transmission and arrange for
|
|
* the retransmit. In persist state, just set snd_max.
|
|
*/
|
|
if (tp->t_force == 0 || TCP_TIMER_ISARMED(tp, TCPT_PERSIST) == 0) {
|
|
tcp_seq startseq = tp->snd_nxt;
|
|
|
|
/*
|
|
* Advance snd_nxt over sequence space of this segment.
|
|
*/
|
|
if (flags & (TH_SYN|TH_FIN)) {
|
|
if (flags & TH_SYN)
|
|
tp->snd_nxt++;
|
|
if (flags & TH_FIN) {
|
|
tp->snd_nxt++;
|
|
tp->t_flags |= TF_SENTFIN;
|
|
}
|
|
}
|
|
if (tp->sack_enable) {
|
|
if (sack_rxmit && (p->rxmit != tp->snd_nxt)) {
|
|
goto timer;
|
|
}
|
|
}
|
|
tp->snd_nxt += len;
|
|
if (SEQ_GT(tp->snd_nxt, tp->snd_max)) {
|
|
tp->snd_max = tp->snd_nxt;
|
|
/*
|
|
* Time this transmission if not a retransmission and
|
|
* not currently timing anything.
|
|
*/
|
|
if (tp->t_rtttime == 0) {
|
|
tp->t_rtttime = now;
|
|
tp->t_rtseq = startseq;
|
|
tcpstat_inc(tcps_segstimed);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Set retransmit timer if not currently set,
|
|
* and not doing an ack or a keep-alive probe.
|
|
* Initial value for retransmit timer is smoothed
|
|
* round-trip time + 2 * round-trip time variance.
|
|
* Initialize shift counter which is used for backoff
|
|
* of retransmit time.
|
|
*/
|
|
timer:
|
|
if (tp->sack_enable && sack_rxmit &&
|
|
TCP_TIMER_ISARMED(tp, TCPT_REXMT) == 0 &&
|
|
tp->snd_nxt != tp->snd_max) {
|
|
TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur);
|
|
if (TCP_TIMER_ISARMED(tp, TCPT_PERSIST)) {
|
|
TCP_TIMER_DISARM(tp, TCPT_PERSIST);
|
|
tp->t_rxtshift = 0;
|
|
}
|
|
}
|
|
|
|
if (TCP_TIMER_ISARMED(tp, TCPT_REXMT) == 0 &&
|
|
tp->snd_nxt != tp->snd_una) {
|
|
TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur);
|
|
if (TCP_TIMER_ISARMED(tp, TCPT_PERSIST)) {
|
|
TCP_TIMER_DISARM(tp, TCPT_PERSIST);
|
|
tp->t_rxtshift = 0;
|
|
}
|
|
}
|
|
|
|
if (len == 0 && so->so_snd.sb_cc &&
|
|
TCP_TIMER_ISARMED(tp, TCPT_REXMT) == 0 &&
|
|
TCP_TIMER_ISARMED(tp, TCPT_PERSIST) == 0) {
|
|
/*
|
|
* Avoid a situation where we do not set persist timer
|
|
* after a zero window condition. For example:
|
|
* 1) A -> B: packet with enough data to fill the window
|
|
* 2) B -> A: ACK for #1 + new data (0 window
|
|
* advertisement)
|
|
* 3) A -> B: ACK for #2, 0 len packet
|
|
*
|
|
* In this case, A will not activate the persist timer,
|
|
* because it chose to send a packet. Unless tcp_output
|
|
* is called for some other reason (delayed ack timer,
|
|
* another input packet from B, socket syscall), A will
|
|
* not send zero window probes.
|
|
*
|
|
* So, if you send a 0-length packet, but there is data
|
|
* in the socket buffer, and neither the rexmt or
|
|
* persist timer is already set, then activate the
|
|
* persist timer.
|
|
*/
|
|
tp->t_rxtshift = 0;
|
|
tcp_setpersist(tp);
|
|
}
|
|
} else
|
|
if (SEQ_GT(tp->snd_nxt + len, tp->snd_max))
|
|
tp->snd_max = tp->snd_nxt + len;
|
|
|
|
tcp_update_sndspace(tp);
|
|
|
|
/*
|
|
* Trace.
|
|
*/
|
|
if (so->so_options & SO_DEBUG)
|
|
tcp_trace(TA_OUTPUT, tp->t_state, tp, tp, mtod(m, caddr_t), 0,
|
|
len);
|
|
|
|
/*
|
|
* Fill in IP length and desired time to live and
|
|
* send to IP level. There should be a better way
|
|
* to handle ttl and tos; we could keep them in
|
|
* the template, but need a way to checksum without them.
|
|
*/
|
|
|
|
#ifdef TCP_ECN
|
|
/*
|
|
* if peer is ECN capable, set the ECT bit in the IP header.
|
|
* but don't set ECT for a pure ack, a retransmit or a window probe.
|
|
*/
|
|
needect = 0;
|
|
if (tcp_do_ecn && (tp->t_flags & TF_ECN_PERMIT)) {
|
|
if (len == 0 || SEQ_LT(tp->snd_nxt, tp->snd_max) ||
|
|
(tp->t_force && len == 1)) {
|
|
/* don't set ECT */
|
|
} else {
|
|
needect = 1;
|
|
tcpstat_inc(tcps_ecn_sndect);
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/* force routing table */
|
|
m->m_pkthdr.ph_rtableid = tp->t_inpcb->inp_rtableid;
|
|
|
|
#if NPF > 0
|
|
pf_mbuf_link_inpcb(m, tp->t_inpcb);
|
|
#endif
|
|
|
|
switch (tp->pf) {
|
|
case 0: /*default to PF_INET*/
|
|
case AF_INET:
|
|
{
|
|
struct ip *ip;
|
|
|
|
ip = mtod(m, struct ip *);
|
|
ip->ip_len = htons(m->m_pkthdr.len);
|
|
packetlen = m->m_pkthdr.len;
|
|
ip->ip_ttl = tp->t_inpcb->inp_ip.ip_ttl;
|
|
ip->ip_tos = tp->t_inpcb->inp_ip.ip_tos;
|
|
#ifdef TCP_ECN
|
|
if (needect)
|
|
ip->ip_tos |= IPTOS_ECN_ECT0;
|
|
#endif
|
|
}
|
|
#if NSTOEPLITZ > 0
|
|
m->m_pkthdr.ph_flowid = tp->t_inpcb->inp_flowid;
|
|
SET(m->m_pkthdr.csum_flags, M_FLOWID);
|
|
#endif
|
|
error = ip_output(m, tp->t_inpcb->inp_options,
|
|
&tp->t_inpcb->inp_route,
|
|
(ip_mtudisc ? IP_MTUDISC : 0), NULL,
|
|
&tp->t_inpcb->inp_seclevel, 0);
|
|
break;
|
|
#ifdef INET6
|
|
case AF_INET6:
|
|
{
|
|
struct ip6_hdr *ip6;
|
|
|
|
ip6 = mtod(m, struct ip6_hdr *);
|
|
ip6->ip6_plen = m->m_pkthdr.len -
|
|
sizeof(struct ip6_hdr);
|
|
packetlen = m->m_pkthdr.len;
|
|
ip6->ip6_nxt = IPPROTO_TCP;
|
|
ip6->ip6_hlim = in6_selecthlim(tp->t_inpcb);
|
|
#ifdef TCP_ECN
|
|
if (needect)
|
|
ip6->ip6_flow |= htonl(IPTOS_ECN_ECT0 << 20);
|
|
#endif
|
|
}
|
|
error = ip6_output(m, tp->t_inpcb->inp_outputopts6,
|
|
&tp->t_inpcb->inp_route, 0, NULL,
|
|
&tp->t_inpcb->inp_seclevel);
|
|
break;
|
|
#endif /* INET6 */
|
|
}
|
|
|
|
if (error) {
|
|
out:
|
|
if (error == ENOBUFS) {
|
|
/*
|
|
* If the interface queue is full, or IP cannot
|
|
* get an mbuf, trigger TCP slow start.
|
|
*/
|
|
tp->snd_cwnd = tp->t_maxseg;
|
|
return (0);
|
|
}
|
|
if (error == EMSGSIZE) {
|
|
/*
|
|
* ip_output() will have already fixed the route
|
|
* for us. tcp_mtudisc() will, as its last action,
|
|
* initiate retransmission, so it is important to
|
|
* not do so here.
|
|
*/
|
|
tcp_mtudisc(tp->t_inpcb, -1);
|
|
return (0);
|
|
}
|
|
if ((error == EHOSTUNREACH || error == ENETDOWN) &&
|
|
TCPS_HAVERCVDSYN(tp->t_state)) {
|
|
tp->t_softerror = error;
|
|
return (0);
|
|
}
|
|
|
|
/* Restart the delayed ACK timer, if necessary. */
|
|
if (TCP_TIMER_ISARMED(tp, TCPT_DELACK))
|
|
TCP_TIMER_ARM(tp, TCPT_DELACK, tcp_delack_msecs);
|
|
|
|
return (error);
|
|
}
|
|
|
|
if (packetlen > tp->t_pmtud_mtu_sent)
|
|
tp->t_pmtud_mtu_sent = packetlen;
|
|
|
|
tcpstat_inc(tcps_sndtotal);
|
|
if (TCP_TIMER_ISARMED(tp, TCPT_DELACK))
|
|
tcpstat_inc(tcps_delack);
|
|
|
|
/*
|
|
* Data sent (as far as we can tell).
|
|
* If this advertises a larger window than any other segment,
|
|
* 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;
|
|
tp->last_ack_sent = tp->rcv_nxt;
|
|
tp->t_sndacktime = now;
|
|
tp->t_flags &= ~TF_ACKNOW;
|
|
TCP_TIMER_DISARM(tp, TCPT_DELACK);
|
|
if (sendalot)
|
|
goto again;
|
|
return (0);
|
|
}
|
|
|
|
void
|
|
tcp_setpersist(struct tcpcb *tp)
|
|
{
|
|
int t = ((tp->t_srtt >> 2) + tp->t_rttvar) >> (1 + TCP_RTT_BASE_SHIFT);
|
|
int msec;
|
|
|
|
if (TCP_TIMER_ISARMED(tp, TCPT_REXMT))
|
|
panic("tcp_output REXMT");
|
|
/*
|
|
* Start/restart persistence timer.
|
|
*/
|
|
if (t < tp->t_rttmin)
|
|
t = tp->t_rttmin;
|
|
TCPT_RANGESET(msec, t * tcp_backoff[tp->t_rxtshift],
|
|
TCPTV_PERSMIN, TCPTV_PERSMAX);
|
|
TCP_TIMER_ARM(tp, TCPT_PERSIST, msec);
|
|
if (tp->t_rxtshift < TCP_MAXRXTSHIFT)
|
|
tp->t_rxtshift++;
|
|
}
|
|
|
|
int
|
|
tcp_chopper(struct mbuf *m0, struct mbuf_list *ml, struct ifnet *ifp,
|
|
u_int mss)
|
|
{
|
|
struct ip *ip = NULL;
|
|
#ifdef INET6
|
|
struct ip6_hdr *ip6 = NULL;
|
|
#endif
|
|
struct tcphdr *th;
|
|
int firstlen, iphlen, hlen, tlen, off;
|
|
int error;
|
|
|
|
ml_init(ml);
|
|
ml_enqueue(ml, m0);
|
|
|
|
if (mss == 0) {
|
|
error = EINVAL;
|
|
goto bad;
|
|
}
|
|
|
|
ip = mtod(m0, struct ip *);
|
|
switch (ip->ip_v) {
|
|
case 4:
|
|
iphlen = ip->ip_hl << 2;
|
|
if (ISSET(ip->ip_off, htons(IP_OFFMASK | IP_MF)) ||
|
|
iphlen != sizeof(struct ip) || ip->ip_p != IPPROTO_TCP) {
|
|
/* only TCP without fragment or IP option supported */
|
|
error = EPROTOTYPE;
|
|
goto bad;
|
|
}
|
|
break;
|
|
#ifdef INET6
|
|
case 6:
|
|
ip = NULL;
|
|
ip6 = mtod(m0, struct ip6_hdr *);
|
|
iphlen = sizeof(struct ip6_hdr);
|
|
if (ip6->ip6_nxt != IPPROTO_TCP) {
|
|
/* only TCP without IPv6 header chain supported */
|
|
error = EPROTOTYPE;
|
|
goto bad;
|
|
}
|
|
break;
|
|
#endif
|
|
default:
|
|
panic("%s: unknown ip version %d", __func__, ip->ip_v);
|
|
}
|
|
|
|
tlen = m0->m_pkthdr.len;
|
|
if (tlen < iphlen + sizeof(struct tcphdr)) {
|
|
error = ENOPROTOOPT;
|
|
goto bad;
|
|
}
|
|
/* IP and TCP header should be contiguous, this check is paranoia */
|
|
if (m0->m_len < iphlen + sizeof(*th)) {
|
|
ml_dequeue(ml);
|
|
if ((m0 = m_pullup(m0, iphlen + sizeof(*th))) == NULL) {
|
|
error = ENOBUFS;
|
|
goto bad;
|
|
}
|
|
ml_enqueue(ml, m0);
|
|
}
|
|
th = (struct tcphdr *)(mtod(m0, caddr_t) + iphlen);
|
|
hlen = iphlen + (th->th_off << 2);
|
|
if (tlen < hlen) {
|
|
error = ENOPROTOOPT;
|
|
goto bad;
|
|
}
|
|
firstlen = MIN(tlen - hlen, mss);
|
|
|
|
CLR(m0->m_pkthdr.csum_flags, M_TCP_TSO);
|
|
|
|
/*
|
|
* Loop through length of payload after first segment,
|
|
* make new header and copy data of each part and link onto chain.
|
|
*/
|
|
for (off = hlen + firstlen; off < tlen; off += mss) {
|
|
struct mbuf *m;
|
|
struct tcphdr *mhth;
|
|
int len;
|
|
|
|
len = MIN(tlen - off, mss);
|
|
|
|
MGETHDR(m, M_DONTWAIT, MT_HEADER);
|
|
if (m == NULL) {
|
|
error = ENOBUFS;
|
|
goto bad;
|
|
}
|
|
ml_enqueue(ml, m);
|
|
if ((error = m_dup_pkthdr(m, m0, M_DONTWAIT)) != 0)
|
|
goto bad;
|
|
|
|
/* IP and TCP header to the end, space for link layer header */
|
|
m->m_len = hlen;
|
|
m_align(m, hlen);
|
|
|
|
/* copy and adjust TCP header */
|
|
mhth = (struct tcphdr *)(mtod(m, caddr_t) + iphlen);
|
|
memcpy(mhth, th, hlen - iphlen);
|
|
mhth->th_seq = htonl(ntohl(th->th_seq) + (off - hlen));
|
|
if (off + len < tlen)
|
|
CLR(mhth->th_flags, TH_PUSH|TH_FIN);
|
|
|
|
/* add mbuf chain with payload */
|
|
m->m_pkthdr.len = hlen + len;
|
|
if ((m->m_next = m_copym(m0, off, len, M_DONTWAIT)) == NULL) {
|
|
error = ENOBUFS;
|
|
goto bad;
|
|
}
|
|
|
|
/* copy and adjust IP header, calculate checksum */
|
|
SET(m->m_pkthdr.csum_flags, M_TCP_CSUM_OUT);
|
|
if (ip) {
|
|
struct ip *mhip;
|
|
|
|
mhip = mtod(m, struct ip *);
|
|
*mhip = *ip;
|
|
mhip->ip_len = htons(hlen + len);
|
|
mhip->ip_id = htons(ip_randomid());
|
|
in_hdr_cksum_out(m, ifp);
|
|
in_proto_cksum_out(m, ifp);
|
|
}
|
|
#ifdef INET6
|
|
if (ip6) {
|
|
struct ip6_hdr *mhip6;
|
|
|
|
mhip6 = mtod(m, struct ip6_hdr *);
|
|
*mhip6 = *ip6;
|
|
mhip6->ip6_plen = htons(hlen - iphlen + len);
|
|
in6_proto_cksum_out(m, ifp);
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Update first segment by trimming what's been copied out
|
|
* and updating header, then send each segment (in order).
|
|
*/
|
|
if (hlen + firstlen < tlen) {
|
|
m_adj(m0, hlen + firstlen - tlen);
|
|
CLR(th->th_flags, TH_PUSH|TH_FIN);
|
|
}
|
|
/* adjust IP header, calculate checksum */
|
|
SET(m0->m_pkthdr.csum_flags, M_TCP_CSUM_OUT);
|
|
if (ip) {
|
|
ip->ip_len = htons(m0->m_pkthdr.len);
|
|
in_hdr_cksum_out(m0, ifp);
|
|
in_proto_cksum_out(m0, ifp);
|
|
}
|
|
#ifdef INET6
|
|
if (ip6) {
|
|
ip6->ip6_plen = htons(m0->m_pkthdr.len - iphlen);
|
|
in6_proto_cksum_out(m0, ifp);
|
|
}
|
|
#endif
|
|
|
|
tcpstat_add(tcps_outpkttso, ml_len(ml));
|
|
return 0;
|
|
|
|
bad:
|
|
tcpstat_inc(tcps_outbadtso);
|
|
ml_purge(ml);
|
|
return error;
|
|
}
|
|
|
|
int
|
|
tcp_if_output_tso(struct ifnet *ifp, struct mbuf **mp, struct sockaddr *dst,
|
|
struct rtentry *rt, uint32_t ifcap, u_int mtu)
|
|
{
|
|
struct mbuf_list ml;
|
|
int error;
|
|
|
|
/* caller must fail later or fragment */
|
|
if (!ISSET((*mp)->m_pkthdr.csum_flags, M_TCP_TSO))
|
|
return 0;
|
|
if ((*mp)->m_pkthdr.ph_mss > mtu) {
|
|
CLR((*mp)->m_pkthdr.csum_flags, M_TCP_TSO);
|
|
return 0;
|
|
}
|
|
|
|
/* network interface hardware will do TSO */
|
|
if (in_ifcap_cksum(*mp, ifp, ifcap)) {
|
|
if (ISSET(ifcap, IFCAP_TSOv4)) {
|
|
in_hdr_cksum_out(*mp, ifp);
|
|
in_proto_cksum_out(*mp, ifp);
|
|
}
|
|
#ifdef INET6
|
|
if (ISSET(ifcap, IFCAP_TSOv6))
|
|
in6_proto_cksum_out(*mp, ifp);
|
|
#endif
|
|
error = ifp->if_output(ifp, *mp, dst, rt);
|
|
if (!error)
|
|
tcpstat_inc(tcps_outhwtso);
|
|
goto done;
|
|
}
|
|
|
|
/* as fallback do TSO in software */
|
|
if ((error = tcp_chopper(*mp, &ml, ifp, (*mp)->m_pkthdr.ph_mss)) ||
|
|
(error = if_output_ml(ifp, &ml, dst, rt)))
|
|
goto done;
|
|
tcpstat_inc(tcps_outswtso);
|
|
|
|
done:
|
|
*mp = NULL;
|
|
return error;
|
|
}
|