965 lines
26 KiB
C
965 lines
26 KiB
C
/* $NetBSD: tcp_subr.c,v 1.64 1999/01/20 03:39:54 thorpej Exp $ */
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/*-
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* Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Jason R. Thorpe and Kevin M. Lahey of the Numerical Aerospace Simulation
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* Facility, NASA Ames Research Center.
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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 NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS 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 PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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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_subr.c 8.2 (Berkeley) 5/24/95
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*/
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#include "opt_tcp_compat_42.h"
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#include "rnd.h"
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#include <sys/param.h>
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#include <sys/proc.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/socket.h>
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#include <sys/socketvar.h>
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#include <sys/protosw.h>
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#include <sys/errno.h>
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#include <sys/kernel.h>
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#include <sys/pool.h>
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#if NRND > 0
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#include <sys/rnd.h>
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#endif
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#include <net/route.h>
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#include <net/if.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/ip_icmp.h>
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#include <netinet/tcp.h>
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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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/* patchable/settable parameters for tcp */
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int tcp_mssdflt = TCP_MSS;
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int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ;
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int tcp_do_rfc1323 = 1; /* window scaling / timestamps (obsolete) */
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int tcp_do_sack = 1; /* selective acknowledgement */
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int tcp_do_win_scale = 1; /* RFC1323 window scaling */
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int tcp_do_timestamps = 1; /* RFC1323 timestamps */
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int tcp_do_newreno = 0; /* Use the New Reno algorithms */
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int tcp_ack_on_push = 0; /* set to enable immediate ACK-on-PUSH */
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int tcp_init_win = 1;
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int tcp_mss_ifmtu = 0;
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#ifdef TCP_COMPAT_42
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int tcp_compat_42 = 1;
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#else
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int tcp_compat_42 = 0;
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#endif
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#ifndef TCBHASHSIZE
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#define TCBHASHSIZE 128
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#endif
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int tcbhashsize = TCBHASHSIZE;
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int tcp_freeq __P((struct tcpcb *));
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struct pool tcpcb_pool;
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struct pool tcp_template_pool;
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/*
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* Tcp initialization
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*/
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void
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tcp_init()
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{
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pool_init(&tcpcb_pool, sizeof(struct tcpcb), 0, 0, 0, "tcpcbpl",
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0, NULL, NULL, M_PCB);
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pool_init(&tcp_template_pool, sizeof(struct tcpiphdr), 0, 0, 0,
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"tcptmpl", 0, NULL, NULL, M_MBUF);
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in_pcbinit(&tcbtable, tcbhashsize, tcbhashsize);
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LIST_INIT(&tcp_delacks);
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if (max_protohdr < sizeof(struct tcpiphdr))
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max_protohdr = sizeof(struct tcpiphdr);
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if (max_linkhdr + sizeof(struct tcpiphdr) > MHLEN)
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panic("tcp_init");
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/* Initialize the compressed state engine. */
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syn_cache_init();
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}
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/*
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* Create template to be used to send tcp packets on a connection.
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* Call after host entry created, allocates an mbuf and fills
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* in a skeletal tcp/ip header, minimizing the amount of work
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* necessary when the connection is used.
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*/
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struct tcpiphdr *
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tcp_template(tp)
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struct tcpcb *tp;
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{
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register struct inpcb *inp = tp->t_inpcb;
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register struct tcpiphdr *n;
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if ((n = tp->t_template) == 0) {
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n = pool_get(&tcp_template_pool, PR_NOWAIT);
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if (n == NULL)
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return (NULL);
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}
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bzero(n->ti_x1, sizeof n->ti_x1);
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n->ti_pr = IPPROTO_TCP;
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n->ti_len = htons(sizeof (struct tcpiphdr) - sizeof (struct ip));
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n->ti_src = inp->inp_laddr;
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n->ti_dst = inp->inp_faddr;
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n->ti_sport = inp->inp_lport;
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n->ti_dport = inp->inp_fport;
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n->ti_seq = 0;
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n->ti_ack = 0;
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n->ti_x2 = 0;
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n->ti_off = 5;
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n->ti_flags = 0;
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n->ti_win = 0;
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n->ti_sum = 0;
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n->ti_urp = 0;
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return (n);
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}
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/*
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* Send a single message to the TCP at address specified by
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* the given TCP/IP header. If m == 0, then we make a copy
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* of the tcpiphdr at ti and send directly to the addressed host.
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* This is used to force keep alive messages out using the TCP
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* template for a connection tp->t_template. If flags are given
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* then we send a message back to the TCP which originated the
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* segment ti, and discard the mbuf containing it and any other
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* attached mbufs.
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*
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* In any case the ack and sequence number of the transmitted
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* segment are as specified by the parameters.
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*/
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int
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tcp_respond(tp, ti, m, ack, seq, flags)
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struct tcpcb *tp;
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register struct tcpiphdr *ti;
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register struct mbuf *m;
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tcp_seq ack, seq;
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int flags;
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{
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struct route iproute, *ro;
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struct rtentry *rt;
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struct sockaddr_in *dst;
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int error, tlen, win = 0;
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if (tp != NULL) {
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if ((flags & TH_RST) == 0)
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win = sbspace(&tp->t_inpcb->inp_socket->so_rcv);
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ro = &tp->t_inpcb->inp_route;
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#ifdef DIAGNOSTIC
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if (!in_hosteq(ti->ti_dst, tp->t_inpcb->inp_faddr))
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panic("tcp_respond: ti_dst != inp_faddr");
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#endif
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} else {
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ro = &iproute;
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bzero(ro, sizeof(*ro));
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}
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if (m == 0) {
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m = m_gethdr(M_DONTWAIT, MT_HEADER);
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if (m == NULL)
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return (ENOBUFS);
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if (tcp_compat_42)
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tlen = 1;
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else
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tlen = 0;
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m->m_data += max_linkhdr;
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*mtod(m, struct tcpiphdr *) = *ti;
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ti = mtod(m, struct tcpiphdr *);
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flags = TH_ACK;
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} else {
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m_freem(m->m_next);
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m->m_next = 0;
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m->m_data = (caddr_t)ti;
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m->m_len = sizeof (struct tcpiphdr);
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tlen = 0;
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#define xchg(a,b,type) { type t; t=a; a=b; b=t; }
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xchg(ti->ti_dst.s_addr, ti->ti_src.s_addr, u_int32_t);
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xchg(ti->ti_dport, ti->ti_sport, u_int16_t);
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#undef xchg
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}
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bzero(ti->ti_x1, sizeof ti->ti_x1);
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ti->ti_seq = htonl(seq);
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ti->ti_ack = htonl(ack);
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ti->ti_x2 = 0;
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if ((flags & TH_SYN) == 0) {
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if (tp)
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ti->ti_win = htons((u_int16_t) (win >> tp->rcv_scale));
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else
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ti->ti_win = htons((u_int16_t)win);
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ti->ti_off = sizeof (struct tcphdr) >> 2;
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tlen += sizeof (struct tcphdr);
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} else
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tlen += ti->ti_off << 2;
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ti->ti_len = htons((u_int16_t)tlen);
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tlen += sizeof (struct ip);
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m->m_len = tlen;
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m->m_pkthdr.len = tlen;
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m->m_pkthdr.rcvif = (struct ifnet *) 0;
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ti->ti_flags = flags;
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ti->ti_urp = 0;
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ti->ti_sum = 0;
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ti->ti_sum = in_cksum(m, tlen);
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((struct ip *)ti)->ip_len = tlen;
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((struct ip *)ti)->ip_ttl = ip_defttl;
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/*
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* If we're doing Path MTU discovery, we need to set DF unless
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* the route's MTU is locked. If we lack a route, we need to
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* look it up now.
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*
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* ip_output() could do this for us, but it's convenient to just
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* do it here unconditionally.
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*/
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if ((rt = ro->ro_rt) == NULL || (rt->rt_flags & RTF_UP) == 0) {
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if (ro->ro_rt != NULL) {
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RTFREE(ro->ro_rt);
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ro->ro_rt = NULL;
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}
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dst = satosin(&ro->ro_dst);
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dst->sin_family = AF_INET;
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dst->sin_len = sizeof(*dst);
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dst->sin_addr = ti->ti_dst;
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rtalloc(ro);
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if ((rt = ro->ro_rt) == NULL) {
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m_freem(m);
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ipstat.ips_noroute++;
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return (EHOSTUNREACH);
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}
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}
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if (ip_mtudisc != 0 && (rt->rt_rmx.rmx_locks & RTV_MTU) == 0)
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((struct ip *)ti)->ip_off |= IP_DF;
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error = ip_output(m, NULL, ro, 0, NULL);
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if (ro == &iproute) {
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RTFREE(ro->ro_rt);
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ro->ro_rt = NULL;
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}
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return (error);
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}
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/*
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* Create a new TCP control block, making an
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* empty reassembly queue and hooking it to the argument
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* protocol control block.
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*/
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struct tcpcb *
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tcp_newtcpcb(inp)
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struct inpcb *inp;
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{
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register struct tcpcb *tp;
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tp = pool_get(&tcpcb_pool, PR_NOWAIT);
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if (tp == NULL)
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return (NULL);
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bzero((caddr_t)tp, sizeof(struct tcpcb));
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LIST_INIT(&tp->segq);
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LIST_INIT(&tp->timeq);
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tp->t_peermss = tcp_mssdflt;
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tp->t_ourmss = tcp_mssdflt;
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tp->t_segsz = tcp_mssdflt;
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tp->t_flags = 0;
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if (tcp_do_rfc1323 && tcp_do_win_scale)
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tp->t_flags |= TF_REQ_SCALE;
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if (tcp_do_rfc1323 && tcp_do_timestamps)
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tp->t_flags |= TF_REQ_TSTMP;
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if (tcp_do_sack == 2)
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tp->t_flags |= TF_WILL_SACK;
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else if (tcp_do_sack == 1)
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tp->t_flags |= TF_WILL_SACK|TF_IGNR_RXSACK;
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tp->t_flags |= TF_CANT_TXSACK;
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tp->t_inpcb = inp;
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/*
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* Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
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* rtt estimate. Set rttvar so that srtt + 2 * rttvar gives
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* reasonable initial retransmit time.
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*/
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tp->t_srtt = TCPTV_SRTTBASE;
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tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << (TCP_RTTVAR_SHIFT + 2 - 1);
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tp->t_rttmin = TCPTV_MIN;
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TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp),
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TCPTV_MIN, TCPTV_REXMTMAX);
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tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
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tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
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inp->inp_ip.ip_ttl = ip_defttl;
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inp->inp_ppcb = (caddr_t)tp;
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return (tp);
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}
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/*
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* Drop a TCP connection, reporting
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* the specified error. If connection is synchronized,
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* then send a RST to peer.
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*/
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struct tcpcb *
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tcp_drop(tp, errno)
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register struct tcpcb *tp;
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int errno;
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{
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struct socket *so = tp->t_inpcb->inp_socket;
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if (TCPS_HAVERCVDSYN(tp->t_state)) {
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tp->t_state = TCPS_CLOSED;
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(void) tcp_output(tp);
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tcpstat.tcps_drops++;
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} else
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tcpstat.tcps_conndrops++;
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if (errno == ETIMEDOUT && tp->t_softerror)
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errno = tp->t_softerror;
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so->so_error = errno;
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return (tcp_close(tp));
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}
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/*
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* Close a TCP control block:
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* discard all space held by the tcp
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* discard internet protocol block
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* wake up any sleepers
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*/
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struct tcpcb *
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tcp_close(tp)
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register struct tcpcb *tp;
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{
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struct inpcb *inp = tp->t_inpcb;
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struct socket *so = inp->inp_socket;
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#ifdef RTV_RTT
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register struct rtentry *rt;
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/*
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* If we sent enough data to get some meaningful characteristics,
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* save them in the routing entry. 'Enough' is arbitrarily
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* defined as the sendpipesize (default 4K) * 16. This would
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* give us 16 rtt samples assuming we only get one sample per
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* window (the usual case on a long haul net). 16 samples is
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* enough for the srtt filter to converge to within 5% of the correct
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* value; fewer samples and we could save a very bogus rtt.
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*
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* Don't update the default route's characteristics and don't
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* update anything that the user "locked".
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*/
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if (SEQ_LT(tp->iss + so->so_snd.sb_hiwat * 16, tp->snd_max) &&
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(rt = inp->inp_route.ro_rt) &&
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!in_nullhost(satosin(rt_key(rt))->sin_addr)) {
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register u_long i = 0;
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if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) {
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i = tp->t_srtt *
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((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2));
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if (rt->rt_rmx.rmx_rtt && i)
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/*
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* filter this update to half the old & half
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* the new values, converting scale.
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* See route.h and tcp_var.h for a
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* description of the scaling constants.
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*/
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rt->rt_rmx.rmx_rtt =
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(rt->rt_rmx.rmx_rtt + i) / 2;
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else
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rt->rt_rmx.rmx_rtt = i;
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}
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if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) {
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i = tp->t_rttvar *
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((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTTVAR_SHIFT + 2));
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if (rt->rt_rmx.rmx_rttvar && i)
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rt->rt_rmx.rmx_rttvar =
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(rt->rt_rmx.rmx_rttvar + i) / 2;
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else
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rt->rt_rmx.rmx_rttvar = i;
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}
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/*
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* update the pipelimit (ssthresh) if it has been updated
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|
* already or if a pipesize was specified & the threshhold
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* got below half the pipesize. I.e., wait for bad news
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* before we start updating, then update on both good
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* and bad news.
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*/
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if (((rt->rt_rmx.rmx_locks & RTV_SSTHRESH) == 0 &&
|
|
(i = tp->snd_ssthresh) && rt->rt_rmx.rmx_ssthresh) ||
|
|
i < (rt->rt_rmx.rmx_sendpipe / 2)) {
|
|
/*
|
|
* convert the limit from user data bytes to
|
|
* packets then to packet data bytes.
|
|
*/
|
|
i = (i + tp->t_segsz / 2) / tp->t_segsz;
|
|
if (i < 2)
|
|
i = 2;
|
|
i *= (u_long)(tp->t_segsz + sizeof (struct tcpiphdr));
|
|
if (rt->rt_rmx.rmx_ssthresh)
|
|
rt->rt_rmx.rmx_ssthresh =
|
|
(rt->rt_rmx.rmx_ssthresh + i) / 2;
|
|
else
|
|
rt->rt_rmx.rmx_ssthresh = i;
|
|
}
|
|
}
|
|
#endif /* RTV_RTT */
|
|
/* free the reassembly queue, if any */
|
|
TCP_REASS_LOCK(tp);
|
|
(void) tcp_freeq(tp);
|
|
TCP_REASS_UNLOCK(tp);
|
|
|
|
TCP_CLEAR_DELACK(tp);
|
|
|
|
if (tp->t_template)
|
|
pool_put(&tcp_template_pool, tp->t_template);
|
|
pool_put(&tcpcb_pool, tp);
|
|
inp->inp_ppcb = 0;
|
|
soisdisconnected(so);
|
|
in_pcbdetach(inp);
|
|
tcpstat.tcps_closed++;
|
|
return ((struct tcpcb *)0);
|
|
}
|
|
|
|
int
|
|
tcp_freeq(tp)
|
|
struct tcpcb *tp;
|
|
{
|
|
register struct ipqent *qe;
|
|
int rv = 0;
|
|
#ifdef TCPREASS_DEBUG
|
|
int i = 0;
|
|
#endif
|
|
|
|
TCP_REASS_LOCK_CHECK(tp);
|
|
|
|
while ((qe = tp->segq.lh_first) != NULL) {
|
|
#ifdef TCPREASS_DEBUG
|
|
printf("tcp_freeq[%p,%d]: %u:%u(%u) 0x%02x\n",
|
|
tp, i++, qe->ipqe_seq, qe->ipqe_seq + qe->ipqe_len,
|
|
qe->ipqe_len, qe->ipqe_flags & (TH_SYN|TH_FIN|TH_RST));
|
|
#endif
|
|
LIST_REMOVE(qe, ipqe_q);
|
|
LIST_REMOVE(qe, ipqe_timeq);
|
|
m_freem(qe->ipqe_m);
|
|
pool_put(&ipqent_pool, qe);
|
|
rv = 1;
|
|
}
|
|
return (rv);
|
|
}
|
|
|
|
/*
|
|
* Protocol drain routine. Called when memory is in short supply.
|
|
*/
|
|
void
|
|
tcp_drain()
|
|
{
|
|
register struct inpcb *inp;
|
|
register struct tcpcb *tp;
|
|
|
|
/*
|
|
* Free the sequence queue of all TCP connections.
|
|
*/
|
|
inp = tcbtable.inpt_queue.cqh_first;
|
|
if (inp) /* XXX */
|
|
for (; inp != (struct inpcb *)&tcbtable.inpt_queue;
|
|
inp = inp->inp_queue.cqe_next) {
|
|
if ((tp = intotcpcb(inp)) != NULL) {
|
|
/*
|
|
* We may be called from a device's interrupt
|
|
* context. If the tcpcb is already busy,
|
|
* just bail out now.
|
|
*/
|
|
if (tcp_reass_lock_try(tp) == 0)
|
|
continue;
|
|
if (tcp_freeq(tp))
|
|
tcpstat.tcps_connsdrained++;
|
|
TCP_REASS_UNLOCK(tp);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Notify a tcp user of an asynchronous error;
|
|
* store error as soft error, but wake up user
|
|
* (for now, won't do anything until can select for soft error).
|
|
*/
|
|
void
|
|
tcp_notify(inp, error)
|
|
struct inpcb *inp;
|
|
int error;
|
|
{
|
|
register struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb;
|
|
register struct socket *so = inp->inp_socket;
|
|
|
|
/*
|
|
* Ignore some errors if we are hooked up.
|
|
* If connection hasn't completed, has retransmitted several times,
|
|
* and receives a second error, give up now. This is better
|
|
* than waiting a long time to establish a connection that
|
|
* can never complete.
|
|
*/
|
|
if (tp->t_state == TCPS_ESTABLISHED &&
|
|
(error == EHOSTUNREACH || error == ENETUNREACH ||
|
|
error == EHOSTDOWN)) {
|
|
return;
|
|
} else if (TCPS_HAVEESTABLISHED(tp->t_state) == 0 &&
|
|
tp->t_rxtshift > 3 && tp->t_softerror)
|
|
so->so_error = error;
|
|
else
|
|
tp->t_softerror = error;
|
|
wakeup((caddr_t) &so->so_timeo);
|
|
sorwakeup(so);
|
|
sowwakeup(so);
|
|
}
|
|
|
|
void *
|
|
tcp_ctlinput(cmd, sa, v)
|
|
int cmd;
|
|
struct sockaddr *sa;
|
|
register void *v;
|
|
{
|
|
register struct ip *ip = v;
|
|
register struct tcphdr *th;
|
|
extern int inetctlerrmap[];
|
|
void (*notify) __P((struct inpcb *, int)) = tcp_notify;
|
|
int errno;
|
|
int nmatch;
|
|
|
|
if ((unsigned)cmd >= PRC_NCMDS)
|
|
return NULL;
|
|
errno = inetctlerrmap[cmd];
|
|
if (cmd == PRC_QUENCH)
|
|
notify = tcp_quench;
|
|
else if (PRC_IS_REDIRECT(cmd))
|
|
notify = in_rtchange, ip = 0;
|
|
else if (cmd == PRC_MSGSIZE && ip_mtudisc)
|
|
notify = tcp_mtudisc, ip = 0;
|
|
else if (cmd == PRC_HOSTDEAD)
|
|
ip = 0;
|
|
else if (errno == 0)
|
|
return NULL;
|
|
if (ip) {
|
|
th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2));
|
|
nmatch = in_pcbnotify(&tcbtable, satosin(sa)->sin_addr,
|
|
th->th_dport, ip->ip_src, th->th_sport, errno, notify);
|
|
if (nmatch == 0 && syn_cache_count &&
|
|
(inetctlerrmap[cmd] == EHOSTUNREACH ||
|
|
inetctlerrmap[cmd] == ENETUNREACH ||
|
|
inetctlerrmap[cmd] == EHOSTDOWN))
|
|
syn_cache_unreach(ip, th);
|
|
} else
|
|
(void)in_pcbnotifyall(&tcbtable, satosin(sa)->sin_addr, errno,
|
|
notify);
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* When a source quence is received, we are being notifed of congestion.
|
|
* Close the congestion window down to the Loss Window (one segment).
|
|
* We will gradually open it again as we proceed.
|
|
*/
|
|
void
|
|
tcp_quench(inp, errno)
|
|
struct inpcb *inp;
|
|
int errno;
|
|
{
|
|
struct tcpcb *tp = intotcpcb(inp);
|
|
|
|
if (tp)
|
|
tp->snd_cwnd = tp->t_segsz;
|
|
}
|
|
|
|
/*
|
|
* On receipt of path MTU corrections, flush old route and replace it
|
|
* with the new one. Retransmit all unacknowledged packets, to ensure
|
|
* that all packets will be received.
|
|
*/
|
|
void
|
|
tcp_mtudisc(inp, errno)
|
|
struct inpcb *inp;
|
|
int errno;
|
|
{
|
|
struct tcpcb *tp = intotcpcb(inp);
|
|
struct rtentry *rt = in_pcbrtentry(inp);
|
|
|
|
if (tp != 0) {
|
|
if (rt != 0) {
|
|
/*
|
|
* If this was not a host route, remove and realloc.
|
|
*/
|
|
if ((rt->rt_flags & RTF_HOST) == 0) {
|
|
in_rtchange(inp, errno);
|
|
if ((rt = in_pcbrtentry(inp)) == 0)
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Slow start out of the error condition. We
|
|
* use the MTU because we know it's smaller
|
|
* than the previously transmitted segment.
|
|
*
|
|
* Note: This is more conservative than the
|
|
* suggestion in draft-floyd-incr-init-win-03.
|
|
*/
|
|
if (rt->rt_rmx.rmx_mtu != 0)
|
|
tp->snd_cwnd =
|
|
TCP_INITIAL_WINDOW(tcp_init_win,
|
|
rt->rt_rmx.rmx_mtu);
|
|
}
|
|
|
|
/*
|
|
* Resend unacknowledged packets.
|
|
*/
|
|
tp->snd_nxt = tp->snd_una;
|
|
tcp_output(tp);
|
|
}
|
|
}
|
|
|
|
|
|
/*
|
|
* Compute the MSS to advertise to the peer. Called only during
|
|
* the 3-way handshake. If we are the server (peer initiated
|
|
* connection), we are called with a pointer to the interface
|
|
* on which the SYN packet arrived. If we are the client (we
|
|
* initiated connection), we are called with a pointer to the
|
|
* interface out which this connection should go.
|
|
*/
|
|
u_long
|
|
tcp_mss_to_advertise(ifp)
|
|
const struct ifnet *ifp;
|
|
{
|
|
extern u_long in_maxmtu;
|
|
u_long mss = 0;
|
|
|
|
/*
|
|
* In order to avoid defeating path MTU discovery on the peer,
|
|
* we advertise the max MTU of all attached networks as our MSS,
|
|
* per RFC 1191, section 3.1.
|
|
*
|
|
* We provide the option to advertise just the MTU of
|
|
* the interface on which we hope this connection will
|
|
* be receiving. If we are responding to a SYN, we
|
|
* will have a pretty good idea about this, but when
|
|
* initiating a connection there is a bit more doubt.
|
|
*
|
|
* We also need to ensure that loopback has a large enough
|
|
* MSS, as the loopback MTU is never included in in_maxmtu.
|
|
*/
|
|
|
|
if (ifp != NULL)
|
|
mss = ifp->if_mtu;
|
|
|
|
if (tcp_mss_ifmtu == 0)
|
|
mss = max(in_maxmtu, mss);
|
|
|
|
if (mss > sizeof(struct tcpiphdr))
|
|
mss -= sizeof(struct tcpiphdr);
|
|
|
|
mss = max(tcp_mssdflt, mss);
|
|
return (mss);
|
|
}
|
|
|
|
/*
|
|
* Set connection variables based on the peer's advertised MSS.
|
|
* We are passed the TCPCB for the actual connection. If we
|
|
* are the server, we are called by the compressed state engine
|
|
* when the 3-way handshake is complete. If we are the client,
|
|
* we are called when we recieve the SYN,ACK from the server.
|
|
*
|
|
* NOTE: Our advertised MSS value must be initialized in the TCPCB
|
|
* before this routine is called!
|
|
*/
|
|
void
|
|
tcp_mss_from_peer(tp, offer)
|
|
struct tcpcb *tp;
|
|
int offer;
|
|
{
|
|
struct inpcb *inp = tp->t_inpcb;
|
|
struct socket *so = inp->inp_socket;
|
|
#if defined(RTV_SPIPE) || defined(RTV_SSTHRESH)
|
|
struct rtentry *rt = in_pcbrtentry(inp);
|
|
#endif
|
|
u_long bufsize;
|
|
int mss;
|
|
|
|
/*
|
|
* As per RFC1122, use the default MSS value, unless they
|
|
* sent us an offer. Do not accept offers less than 32 bytes.
|
|
*/
|
|
mss = tcp_mssdflt;
|
|
if (offer)
|
|
mss = offer;
|
|
mss = max(mss, 32); /* sanity */
|
|
tp->t_peermss = mss;
|
|
mss -= (tcp_optlen(tp) + ip_optlen(tp->t_inpcb));
|
|
|
|
/*
|
|
* If there's a pipesize, change the socket buffer to that size.
|
|
* Make the socket buffer an integral number of MSS units. If
|
|
* the MSS is larger than the socket buffer, artificially decrease
|
|
* the MSS.
|
|
*/
|
|
#ifdef RTV_SPIPE
|
|
if (rt != NULL && rt->rt_rmx.rmx_sendpipe != 0)
|
|
bufsize = rt->rt_rmx.rmx_sendpipe;
|
|
else
|
|
#endif
|
|
bufsize = so->so_snd.sb_hiwat;
|
|
if (bufsize < mss)
|
|
mss = bufsize;
|
|
else {
|
|
bufsize = roundup(bufsize, mss);
|
|
if (bufsize > sb_max)
|
|
bufsize = sb_max;
|
|
(void) sbreserve(&so->so_snd, bufsize);
|
|
}
|
|
tp->t_segsz = mss;
|
|
|
|
#ifdef RTV_SSTHRESH
|
|
if (rt != NULL && rt->rt_rmx.rmx_ssthresh) {
|
|
/*
|
|
* There's some sort of gateway or interface buffer
|
|
* limit on the path. Use this to set the slow
|
|
* start threshold, but set the threshold to no less
|
|
* than 2 * MSS.
|
|
*/
|
|
tp->snd_ssthresh = max(2 * mss, rt->rt_rmx.rmx_ssthresh);
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Processing necessary when a TCP connection is established.
|
|
*/
|
|
void
|
|
tcp_established(tp)
|
|
struct tcpcb *tp;
|
|
{
|
|
struct inpcb *inp = tp->t_inpcb;
|
|
struct socket *so = inp->inp_socket;
|
|
#ifdef RTV_RPIPE
|
|
struct rtentry *rt = in_pcbrtentry(inp);
|
|
#endif
|
|
u_long bufsize;
|
|
|
|
tp->t_state = TCPS_ESTABLISHED;
|
|
TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepidle);
|
|
|
|
#ifdef RTV_RPIPE
|
|
if (rt != NULL && rt->rt_rmx.rmx_recvpipe != 0)
|
|
bufsize = rt->rt_rmx.rmx_recvpipe;
|
|
else
|
|
#endif
|
|
bufsize = so->so_rcv.sb_hiwat;
|
|
if (bufsize > tp->t_ourmss) {
|
|
bufsize = roundup(bufsize, tp->t_ourmss);
|
|
if (bufsize > sb_max)
|
|
bufsize = sb_max;
|
|
(void) sbreserve(&so->so_rcv, bufsize);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Check if there's an initial rtt or rttvar. Convert from the
|
|
* route-table units to scaled multiples of the slow timeout timer.
|
|
* Called only during the 3-way handshake.
|
|
*/
|
|
void
|
|
tcp_rmx_rtt(tp)
|
|
struct tcpcb *tp;
|
|
{
|
|
#ifdef RTV_RTT
|
|
struct rtentry *rt;
|
|
int rtt;
|
|
|
|
if ((rt = in_pcbrtentry(tp->t_inpcb)) == NULL)
|
|
return;
|
|
|
|
if (tp->t_srtt == 0 && (rtt = rt->rt_rmx.rmx_rtt)) {
|
|
/*
|
|
* XXX The lock bit for MTU indicates that the value
|
|
* is also a minimum value; this is subject to time.
|
|
*/
|
|
if (rt->rt_rmx.rmx_locks & RTV_RTT)
|
|
TCPT_RANGESET(tp->t_rttmin,
|
|
rtt / (RTM_RTTUNIT / PR_SLOWHZ),
|
|
TCPTV_MIN, TCPTV_REXMTMAX);
|
|
tp->t_srtt = rtt /
|
|
((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2));
|
|
if (rt->rt_rmx.rmx_rttvar) {
|
|
tp->t_rttvar = rt->rt_rmx.rmx_rttvar /
|
|
((RTM_RTTUNIT / PR_SLOWHZ) >>
|
|
(TCP_RTTVAR_SHIFT + 2));
|
|
} else {
|
|
/* Default variation is +- 1 rtt */
|
|
tp->t_rttvar =
|
|
tp->t_srtt >> (TCP_RTT_SHIFT - TCP_RTTVAR_SHIFT);
|
|
}
|
|
TCPT_RANGESET(tp->t_rxtcur,
|
|
((tp->t_srtt >> 2) + tp->t_rttvar) >> (1 + 2),
|
|
tp->t_rttmin, TCPTV_REXMTMAX);
|
|
}
|
|
#endif
|
|
}
|
|
|
|
tcp_seq tcp_iss_seq = 0; /* tcp initial seq # */
|
|
|
|
/*
|
|
* Get a new sequence value given a tcp control block
|
|
*/
|
|
tcp_seq
|
|
tcp_new_iss(tp, len, addin)
|
|
void *tp;
|
|
u_long len;
|
|
tcp_seq addin;
|
|
{
|
|
tcp_seq tcp_iss;
|
|
|
|
/*
|
|
* add randomness about this connection, but do not estimate
|
|
* entropy from the timing, since the physical device driver would
|
|
* have done that for us.
|
|
*/
|
|
#if NRND > 0
|
|
if (tp != NULL)
|
|
rnd_add_data(NULL, tp, len, 0);
|
|
#endif
|
|
|
|
/*
|
|
* randomize.
|
|
*/
|
|
#if NRND > 0
|
|
rnd_extract_data(&tcp_iss, sizeof(tcp_iss), RND_EXTRACT_ANY);
|
|
#else
|
|
tcp_iss = random();
|
|
#endif
|
|
|
|
/*
|
|
* If we were asked to add some amount to a known value,
|
|
* we will take a random value obtained above, mask off the upper
|
|
* bits, and add in the known value. We also add in a constant to
|
|
* ensure that we are at least a certain distance from the original
|
|
* value.
|
|
*
|
|
* This is used when an old connection is in timed wait
|
|
* and we have a new one coming in, for instance.
|
|
*/
|
|
if (addin != 0) {
|
|
#ifdef TCPISS_DEBUG
|
|
printf("Random %08x, ", tcp_iss);
|
|
#endif
|
|
tcp_iss &= TCP_ISS_RANDOM_MASK;
|
|
tcp_iss += addin + TCP_ISSINCR;
|
|
#ifdef TCPISS_DEBUG
|
|
printf("Old ISS %08x, ISS %08x\n", addin, tcp_iss);
|
|
#endif
|
|
} else {
|
|
tcp_iss &= TCP_ISS_RANDOM_MASK;
|
|
tcp_iss += tcp_iss_seq;
|
|
tcp_iss_seq += TCP_ISSINCR;
|
|
#ifdef TCPISS_DEBUG
|
|
printf("ISS %08x\n", tcp_iss);
|
|
#endif
|
|
}
|
|
|
|
if (tcp_compat_42) {
|
|
/*
|
|
* Limit it to the positive range for really old TCP
|
|
* implementations.
|
|
*/
|
|
if (tcp_iss >= 0x80000000)
|
|
tcp_iss &= 0x7fffffff; /* XXX */
|
|
}
|
|
|
|
return tcp_iss;
|
|
}
|
|
|
|
|
|
/*
|
|
* Determine the length of the TCP options for this connection.
|
|
*
|
|
* XXX: What do we do for SACK, when we add that? Just reserve
|
|
* all of the space? Otherwise we can't exactly be incrementing
|
|
* cwnd by an amount that varies depending on the amount we last
|
|
* had to SACK!
|
|
*/
|
|
|
|
u_int
|
|
tcp_optlen(tp)
|
|
struct tcpcb *tp;
|
|
{
|
|
if ((tp->t_flags & (TF_REQ_TSTMP|TF_RCVD_TSTMP|TF_NOOPT)) ==
|
|
(TF_REQ_TSTMP | TF_RCVD_TSTMP))
|
|
return TCPOLEN_TSTAMP_APPA;
|
|
else
|
|
return 0;
|
|
}
|