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NetBSD/sys/netinet/tcp_subr.c

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/* $NetBSD: tcp_subr.c,v 1.76 1999/08/09 10:55:29 itojun Exp $ */
/*
* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the project nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*-
* Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe and Kevin M. Lahey of the Numerical Aerospace Simulation
* Facility, NASA Ames Research Center.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)tcp_subr.c 8.2 (Berkeley) 5/24/95
*/
#include "opt_inet.h"
#include "opt_ipsec.h"
#include "opt_tcp_compat_42.h"
#include "rnd.h"
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/protosw.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/pool.h>
#if NRND > 0
#include <sys/rnd.h>
#endif
#include <net/route.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/ip_var.h>
#include <netinet/ip_icmp.h>
#ifdef INET6
#ifndef INET
#include <netinet/in.h>
#endif
#include <netinet/ip6.h>
#include <netinet6/in6_pcb.h>
#include <netinet6/ip6_var.h>
#include <netinet6/in6_var.h>
#endif
#include <netinet/tcp.h>
#include <netinet/tcp_fsm.h>
#include <netinet/tcp_seq.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <netinet/tcpip.h>
#ifdef IPSEC
#include <netinet6/ipsec.h>
#endif /*IPSEC*/
#ifdef INET6
struct in6pcb tcb6;
#endif
/* patchable/settable parameters for tcp */
int tcp_mssdflt = TCP_MSS;
int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ;
int tcp_do_rfc1323 = 1; /* window scaling / timestamps (obsolete) */
int tcp_do_sack = 1; /* selective acknowledgement */
int tcp_do_win_scale = 1; /* RFC1323 window scaling */
int tcp_do_timestamps = 1; /* RFC1323 timestamps */
int tcp_do_newreno = 0; /* Use the New Reno algorithms */
int tcp_ack_on_push = 0; /* set to enable immediate ACK-on-PUSH */
int tcp_init_win = 1;
int tcp_mss_ifmtu = 0;
#ifdef TCP_COMPAT_42
int tcp_compat_42 = 1;
#else
int tcp_compat_42 = 0;
#endif
#ifndef TCBHASHSIZE
#define TCBHASHSIZE 128
#endif
int tcbhashsize = TCBHASHSIZE;
int tcp_freeq __P((struct tcpcb *));
struct pool tcpcb_pool;
/*
* Tcp initialization
*/
void
tcp_init()
{
int hlen;
pool_init(&tcpcb_pool, sizeof(struct tcpcb), 0, 0, 0, "tcpcbpl",
0, NULL, NULL, M_PCB);
in_pcbinit(&tcbtable, tcbhashsize, tcbhashsize);
#ifdef INET6
tcb6.in6p_next = tcb6.in6p_prev = &tcb6;
#endif
LIST_INIT(&tcp_delacks);
hlen = sizeof(struct ip) + sizeof(struct tcphdr);
#ifdef INET6
if (sizeof(struct ip) < sizeof(struct ip6_hdr))
hlen = sizeof(struct ip6_hdr) + sizeof(struct tcphdr);
#endif
if (max_protohdr < hlen)
max_protohdr = hlen;
if (max_linkhdr + hlen > MHLEN)
panic("tcp_init");
/* Initialize the compressed state engine. */
syn_cache_init();
}
/*
* Create template to be used to send tcp packets on a connection.
* Call after host entry created, allocates an mbuf and fills
* in a skeletal tcp/ip header, minimizing the amount of work
* necessary when the connection is used.
*/
struct mbuf *
tcp_template(tp)
struct tcpcb *tp;
{
register struct inpcb *inp = tp->t_inpcb;
#ifdef INET6
register struct in6pcb *in6p = tp->t_in6pcb;
#endif
register struct tcphdr *n;
register struct mbuf *m;
int hlen;
switch (tp->t_family) {
case AF_INET:
hlen = sizeof(struct ip);
if (inp)
break;
#ifdef INET6
if (in6p) {
/* mapped addr case */
if (IN6_IS_ADDR_V4MAPPED(&in6p->in6p_laddr)
&& IN6_IS_ADDR_V4MAPPED(&in6p->in6p_faddr))
break;
}
#endif
return NULL; /*EINVAL*/
#ifdef INET6
case AF_INET6:
hlen = sizeof(struct ip6_hdr);
if (in6p) {
/* more sainty check? */
break;
}
return NULL; /*EINVAL*/
#endif
default:
hlen = 0; /*pacify gcc*/
return NULL; /*EAFNOSUPPORT*/
}
if ((m = tp->t_template) == 0) {
MGETHDR(m, M_DONTWAIT, MT_HEADER);
if (m) {
MCLGET(m, M_DONTWAIT);
if ((m->m_flags & M_EXT) == 0) {
m_free(m);
m = NULL;
}
}
if (m == NULL)
return NULL;
m->m_len = hlen + sizeof(struct tcphdr);
}
bzero(mtod(m, caddr_t), m->m_len);
switch (tp->t_family) {
case AF_INET:
{
struct ipovly *ipov;
mtod(m, struct ip *)->ip_v = 4;
ipov = mtod(m, struct ipovly *);
ipov->ih_pr = IPPROTO_TCP;
ipov->ih_len = htons(sizeof(struct tcphdr));
if (inp) {
ipov->ih_src = inp->inp_laddr;
ipov->ih_dst = inp->inp_faddr;
}
#ifdef INET6
else if (in6p) {
/* mapped addr case */
bcopy(&in6p->in6p_laddr.s6_addr32[3], &ipov->ih_src,
sizeof(ipov->ih_src));
bcopy(&in6p->in6p_faddr.s6_addr32[3], &ipov->ih_dst,
sizeof(ipov->ih_dst));
}
#endif
break;
}
#ifdef INET6
case AF_INET6:
{
struct ip6_hdr *ip6;
mtod(m, struct ip *)->ip_v = 6;
ip6 = mtod(m, struct ip6_hdr *);
ip6->ip6_nxt = IPPROTO_TCP;
ip6->ip6_plen = htons(sizeof(struct tcphdr));
ip6->ip6_src = in6p->in6p_laddr;
ip6->ip6_dst = in6p->in6p_faddr;
ip6->ip6_flow = in6p->in6p_flowinfo & IPV6_FLOWINFO_MASK;
if (ip6_auto_flowlabel) {
ip6->ip6_flow &= ~IPV6_FLOWLABEL_MASK;
ip6->ip6_flow |=
(htonl(ip6_flow_seq++) & IPV6_FLOWLABEL_MASK);
}
ip6->ip6_vfc = IPV6_VERSION;
break;
}
#endif
}
n = (struct tcphdr *)(mtod(m, caddr_t) + hlen);
if (inp) {
n->th_sport = inp->inp_lport;
n->th_dport = inp->inp_fport;
}
#ifdef INET6
else if (in6p) {
n->th_sport = in6p->in6p_lport;
n->th_dport = in6p->in6p_fport;
}
#endif
n->th_seq = 0;
n->th_ack = 0;
n->th_x2 = 0;
n->th_off = 5;
n->th_flags = 0;
n->th_win = 0;
n->th_sum = 0;
n->th_urp = 0;
return (m);
}
/*
* Send a single message to the TCP at address specified by
* the given TCP/IP header. If m == 0, then we make a copy
* of the tcpiphdr at ti and send directly to the addressed host.
* This is used to force keep alive messages out using the TCP
* template for a connection tp->t_template. If flags are given
* then we send a message back to the TCP which originated the
* segment ti, and discard the mbuf containing it and any other
* attached mbufs.
*
* In any case the ack and sequence number of the transmitted
* segment are as specified by the parameters.
*/
int
tcp_respond(tp, template, m, th0, ack, seq, flags)
struct tcpcb *tp;
struct mbuf *template;
register struct mbuf *m;
struct tcphdr *th0;
tcp_seq ack, seq;
int flags;
{
#ifndef INET6
struct route iproute;
#else
struct route_in6 iproute; /* sizeof(route_in6) > sizeof(route) */
#endif
struct route *ro;
struct rtentry *rt;
int error, tlen, win = 0;
int hlen;
struct ip *ip;
#ifdef INET6
struct ip6_hdr *ip6;
#endif
int family; /* family on packet, not inpcb/in6pcb! */
struct tcphdr *th;
if (tp != NULL && (flags & TH_RST) == 0) {
if (tp->t_inpcb)
win = sbspace(&tp->t_inpcb->inp_socket->so_rcv);
#ifdef INET6
else if (tp->t_in6pcb)
win = sbspace(&tp->t_in6pcb->in6p_socket->so_rcv);
#endif
}
ip = NULL;
#ifdef INET6
ip6 = NULL;
#endif
if (m == 0) {
if (!template)
return EINVAL;
/* get family information from template */
switch (mtod(template, struct ip *)->ip_v) {
case 4:
family = AF_INET;
hlen = sizeof(struct ip);
break;
#ifdef INET6
case 6:
family = AF_INET6;
hlen = sizeof(struct ip6_hdr);
break;
#endif
default:
return EAFNOSUPPORT;
}
MGETHDR(m, M_DONTWAIT, MT_HEADER);
if (m) {
MCLGET(m, M_DONTWAIT);
if ((m->m_flags & M_EXT) == 0) {
m_free(m);
m = NULL;
}
}
if (m == NULL)
return (ENOBUFS);
if (tcp_compat_42)
tlen = 1;
else
tlen = 0;
m->m_data += max_linkhdr;
bcopy(mtod(template, caddr_t), mtod(m, caddr_t),
template->m_len);
switch (family) {
case AF_INET:
ip = mtod(m, struct ip *);
th = (struct tcphdr *)(ip + 1);
break;
#ifdef INET6
case AF_INET6:
ip6 = mtod(m, struct ip6_hdr *);
th = (struct tcphdr *)(ip6 + 1);
break;
#endif
default: /*pacify gcc*/
ip = NULL;
#ifdef INET6
ip6 = NULL;
#endif
th = NULL;
break;
}
flags = TH_ACK;
} else {
/* get family information from m */
switch (mtod(m, struct ip *)->ip_v) {
case 4:
family = AF_INET;
hlen = sizeof(struct ip);
break;
#ifdef INET6
case 6:
family = AF_INET6;
hlen = sizeof(struct ip6_hdr);
break;
#endif
default:
if (m)
m_freem(m);
return EAFNOSUPPORT;
}
/* template pointer almost has no meaning */
m_freem(m->m_next);
m->m_next = 0;
m->m_len = hlen + sizeof(struct tcphdr);
if ((m->m_flags & M_PKTHDR) == 0) {
printf("non PKTHDR to tcp_respond\n");
m_freem(m);
return EINVAL;
}
tlen = 0;
#define xchg(a,b,type) { type t; t=a; a=b; b=t; }
switch (family) {
case AF_INET:
ip = mtod(m, struct ip *);
th = (struct tcphdr *)(ip + 1);
xchg(ip->ip_dst, ip->ip_src, struct in_addr);
ip->ip_p = IPPROTO_TCP;
break;
#ifdef INET6
case AF_INET6:
ip6 = mtod(m, struct ip6_hdr *);
th = (struct tcphdr *)(ip6 + 1);
xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
ip6->ip6_nxt = IPPROTO_TCP;
break;
#endif
}
*th = *th0;
xchg(th->th_dport, th->th_sport, u_int16_t);
#undef xchg
}
th->th_seq = htonl(seq);
th->th_ack = htonl(ack);
th->th_x2 = 0;
if ((flags & TH_SYN) == 0) {
if (tp)
th->th_win = htons((u_int16_t) (win >> tp->rcv_scale));
else
th->th_win = htons((u_int16_t)win);
th->th_off = sizeof (struct tcphdr) >> 2;
tlen += sizeof (struct tcphdr);
} else
tlen += th->th_off << 2;
m->m_len = hlen + tlen;
m->m_pkthdr.len = hlen + tlen;
m->m_pkthdr.rcvif = (struct ifnet *) 0;
th->th_flags = flags;
th->th_urp = 0;
switch (family) {
case AF_INET:
{
struct ipovly *ipov = (struct ipovly *)ip;
bzero(ipov->ih_x1, sizeof ipov->ih_x1);
ipov->ih_len = htons((u_int16_t)tlen);
th->th_sum = 0;
th->th_sum = in_cksum(m, hlen + tlen);
ip->ip_len = hlen + tlen; /*will be flipped on output*/
ip->ip_ttl = ip_defttl;
break;
}
#ifdef INET6
case AF_INET6:
{
th->th_sum = 0;
th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(struct ip6_hdr),
tlen);
ip6->ip6_plen = ntohs(tlen);
ip6->ip6_hlim = ip6_defhlim;
ip6->ip6_flow &= ~IPV6_FLOWINFO_MASK;
if (ip6_auto_flowlabel) {
ip6->ip6_flow |=
(htonl(ip6_flow_seq++) & IPV6_FLOWLABEL_MASK);
}
break;
}
#endif
}
#ifdef IPSEC
m->m_pkthdr.rcvif = NULL;
#endif /*IPSEC*/
/*
* If we're doing Path MTU discovery, we need to set DF unless
* the route's MTU is locked. If we lack a route, we need to
* look it up now.
*
* ip_output() could do this for us, but it's convenient to just
* do it here unconditionally.
*/
if (tp != NULL && tp->t_inpcb != NULL) {
ro = &tp->t_inpcb->inp_route;
#ifdef IPSEC
m->m_pkthdr.rcvif = (struct ifnet *)tp->t_inpcb->inp_socket;
#endif
#ifdef DIAGNOSTIC
if (family != AF_INET)
panic("tcp_respond: address family mismatch");
if (!in_hosteq(ip->ip_dst, tp->t_inpcb->inp_faddr)) {
panic("tcp_respond: ip_dst %x != inp_faddr %x",
ntohl(ip->ip_dst.s_addr),
ntohl(tp->t_inpcb->inp_faddr.s_addr));
}
#endif
}
#ifdef INET6
else if (tp != NULL && tp->t_in6pcb != NULL) {
ro = (struct route *)&tp->t_in6pcb->in6p_route;
#ifdef IPSEC
m->m_pkthdr.rcvif = (struct ifnet *)tp->t_in6pcb->in6p_socket;
#endif
#ifdef DIAGNOSTIC
if (family == AF_INET) {
if (!IN6_IS_ADDR_V4MAPPED(&tp->t_in6pcb->in6p_faddr))
panic("tcp_respond: not mapped addr");
if (bcmp(&ip->ip_dst,
&tp->t_in6pcb->in6p_faddr.s6_addr32[3],
sizeof(ip->ip_dst)) != 0) {
panic("tcp_respond: ip_dst != in6p_faddr");
}
} else if (family == AF_INET6) {
if (!IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &tp->t_in6pcb->in6p_faddr))
panic("tcp_respond: ip6_dst != in6p_faddr");
} else
panic("tcp_respond: address family mismatch");
#endif
}
#endif
else {
ro = (struct route *)&iproute;
bzero(ro, sizeof(iproute));
}
if ((rt = ro->ro_rt) == NULL || (rt->rt_flags & RTF_UP) == 0) {
if (ro->ro_rt != NULL) {
RTFREE(ro->ro_rt);
ro->ro_rt = NULL;
}
switch (family) {
case AF_INET:
{
struct sockaddr_in *dst;
dst = satosin(&ro->ro_dst);
dst->sin_family = AF_INET;
dst->sin_len = sizeof(*dst);
dst->sin_addr = ip->ip_dst;
break;
}
#ifdef INET6
case AF_INET6:
{
struct sockaddr_in6 *dst;
dst = satosin6(&ro->ro_dst);
bzero(dst, sizeof(*dst));
dst->sin6_family = AF_INET6;
dst->sin6_len = sizeof(*dst);
dst->sin6_addr = ip6->ip6_dst;
break;
}
#endif
}
rtalloc(ro);
if ((rt = ro->ro_rt) == NULL) {
m_freem(m);
switch (family) {
case AF_INET:
ipstat.ips_noroute++;
break;
#ifdef INET6
case AF_INET6:
ip6stat.ip6s_noroute++;
break;
#endif
}
return (EHOSTUNREACH);
}
}
switch (family) {
case AF_INET:
if (ip_mtudisc != 0 && (rt->rt_rmx.rmx_locks & RTV_MTU) == 0)
ip->ip_off |= IP_DF;
error = ip_output(m, NULL, ro, 0, NULL);
break;
#ifdef INET6
case AF_INET6:
error = ip6_output(m, NULL, (struct route_in6 *)ro, 0, NULL);
break;
#endif
default:
error = EAFNOSUPPORT;
break;
}
if (ro == (struct route *)&iproute) {
RTFREE(ro->ro_rt);
ro->ro_rt = NULL;
}
return (error);
}
/*
* Create a new TCP control block, making an
* empty reassembly queue and hooking it to the argument
* protocol control block.
*/
struct tcpcb *
tcp_newtcpcb(family, aux)
int family; /* selects inpcb, or in6pcb */
void *aux;
{
register struct tcpcb *tp;
switch (family) {
case PF_INET:
break;
#ifdef INET6
case PF_INET6:
break;
#endif
default:
return NULL;
}
tp = pool_get(&tcpcb_pool, PR_NOWAIT);
if (tp == NULL)
return (NULL);
bzero((caddr_t)tp, sizeof(struct tcpcb));
LIST_INIT(&tp->segq);
LIST_INIT(&tp->timeq);
tp->t_family = family; /* may be overridden later on */
tp->t_peermss = tcp_mssdflt;
tp->t_ourmss = tcp_mssdflt;
tp->t_segsz = tcp_mssdflt;
tp->t_flags = 0;
if (tcp_do_rfc1323 && tcp_do_win_scale)
tp->t_flags |= TF_REQ_SCALE;
if (tcp_do_rfc1323 && tcp_do_timestamps)
tp->t_flags |= TF_REQ_TSTMP;
if (tcp_do_sack == 2)
tp->t_flags |= TF_WILL_SACK;
else if (tcp_do_sack == 1)
tp->t_flags |= TF_WILL_SACK|TF_IGNR_RXSACK;
tp->t_flags |= TF_CANT_TXSACK;
switch (family) {
case PF_INET:
tp->t_inpcb = (struct inpcb *)aux;
break;
#ifdef INET6
case PF_INET6:
tp->t_in6pcb = (struct in6pcb *)aux;
break;
#endif
}
/*
* Init srtt to TCPTV_SRTTBASE (0), so we can tell that we have no
* rtt estimate. Set rttvar so that srtt + 2 * rttvar gives
* reasonable initial retransmit time.
*/
tp->t_srtt = TCPTV_SRTTBASE;
tp->t_rttvar = tcp_rttdflt * PR_SLOWHZ << (TCP_RTTVAR_SHIFT + 2 - 1);
tp->t_rttmin = TCPTV_MIN;
TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp),
TCPTV_MIN, TCPTV_REXMTMAX);
tp->snd_cwnd = TCP_MAXWIN << TCP_MAX_WINSHIFT;
tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
if (family == AF_INET) {
struct inpcb *inp = (struct inpcb *)aux;
inp->inp_ip.ip_ttl = ip_defttl;
inp->inp_ppcb = (caddr_t)tp;
}
#ifdef INET6
else if (family == AF_INET6) {
struct in6pcb *in6p = (struct in6pcb *)aux;
in6p->in6p_ip6.ip6_hlim = ip6_defhlim;
in6p->in6p_ppcb = (caddr_t)tp;
}
#endif
return (tp);
}
/*
* Drop a TCP connection, reporting
* the specified error. If connection is synchronized,
* then send a RST to peer.
*/
struct tcpcb *
tcp_drop(tp, errno)
register struct tcpcb *tp;
int errno;
{
struct socket *so;
if (tp->t_inpcb)
so = tp->t_inpcb->inp_socket;
#ifdef INET6
else if (tp->t_in6pcb)
so = tp->t_in6pcb->in6p_socket;
#endif
else
return NULL;
if (TCPS_HAVERCVDSYN(tp->t_state)) {
tp->t_state = TCPS_CLOSED;
(void) tcp_output(tp);
tcpstat.tcps_drops++;
} else
tcpstat.tcps_conndrops++;
if (errno == ETIMEDOUT && tp->t_softerror)
errno = tp->t_softerror;
so->so_error = errno;
return (tcp_close(tp));
}
/*
* Close a TCP control block:
* discard all space held by the tcp
* discard internet protocol block
* wake up any sleepers
*/
struct tcpcb *
tcp_close(tp)
register struct tcpcb *tp;
{
struct inpcb *inp;
#ifdef INET6
struct in6pcb *in6p;
#endif
struct socket *so;
#ifdef RTV_RTT
register struct rtentry *rt;
#endif
struct route *ro;
inp = tp->t_inpcb;
#ifdef INET6
in6p = tp->t_in6pcb;
#endif
so = NULL;
ro = NULL;
if (inp) {
so = inp->inp_socket;
ro = &inp->inp_route;
}
#ifdef INET6
else if (in6p) {
so = in6p->in6p_socket;
ro = (struct route *)&in6p->in6p_route;
}
#endif
#ifdef RTV_RTT
/*
* If we sent enough data to get some meaningful characteristics,
* save them in the routing entry. 'Enough' is arbitrarily
* defined as the sendpipesize (default 4K) * 16. This would
* give us 16 rtt samples assuming we only get one sample per
* window (the usual case on a long haul net). 16 samples is
* enough for the srtt filter to converge to within 5% of the correct
* value; fewer samples and we could save a very bogus rtt.
*
* Don't update the default route's characteristics and don't
* update anything that the user "locked".
*/
if (SEQ_LT(tp->iss + so->so_snd.sb_hiwat * 16, tp->snd_max) &&
ro && (rt = ro->ro_rt) &&
!in_nullhost(satosin(rt_key(rt))->sin_addr)) {
register u_long i = 0;
if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) {
i = tp->t_srtt *
((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTT_SHIFT + 2));
if (rt->rt_rmx.rmx_rtt && i)
/*
* filter this update to half the old & half
* the new values, converting scale.
* See route.h and tcp_var.h for a
* description of the scaling constants.
*/
rt->rt_rmx.rmx_rtt =
(rt->rt_rmx.rmx_rtt + i) / 2;
else
rt->rt_rmx.rmx_rtt = i;
}
if ((rt->rt_rmx.rmx_locks & RTV_RTTVAR) == 0) {
i = tp->t_rttvar *
((RTM_RTTUNIT / PR_SLOWHZ) >> (TCP_RTTVAR_SHIFT + 2));
if (rt->rt_rmx.rmx_rttvar && i)
rt->rt_rmx.rmx_rttvar =
(rt->rt_rmx.rmx_rttvar + i) / 2;
else
rt->rt_rmx.rmx_rttvar = i;
}
/*
* update the pipelimit (ssthresh) if it has been updated
* already or if a pipesize was specified & the threshhold
* got below half the pipesize. I.e., wait for bad news
* before we start updating, then update on both good
* and bad news.
*/
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) {
m_free(tp->t_template);
tp->t_template = NULL;
}
pool_put(&tcpcb_pool, tp);
if (inp) {
inp->inp_ppcb = 0;
soisdisconnected(so);
in_pcbdetach(inp);
}
#ifdef INET6
else if (in6p) {
in6p->in6p_ppcb = 0;
soisdisconnected(so);
in6_pcbdetach(in6p);
}
#endif
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);
}
#if defined(INET6) && !defined(TCP6)
void
tcp6_notify(in6p, error)
struct in6pcb *in6p;
int error;
{
register struct tcpcb *tp = (struct tcpcb *)in6p->in6p_ppcb;
register struct socket *so = in6p->in6p_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);
}
#endif
#if defined(INET6) && !defined(TCP6)
void
tcp6_ctlinput(cmd, sa, ip6, m, off)
int cmd;
struct sockaddr *sa;
register struct ip6_hdr *ip6;
struct mbuf *m;
int off;
{
register struct tcphdr *thp;
struct tcphdr th;
void (*notify) __P((struct in6pcb *, int)) = tcp6_notify;
int nmatch;
extern struct in6_addr zeroin6_addr; /* netinet6/in6_pcb.c */
struct sockaddr_in6 sa6;
if (sa->sa_family != AF_INET6 ||
sa->sa_len != sizeof(struct sockaddr_in6))
return;
if (cmd == PRC_QUENCH)
notify = tcp6_quench;
else if (cmd == PRC_MSGSIZE)
notify = tcp6_mtudisc;
else if (!PRC_IS_REDIRECT(cmd) &&
((unsigned)cmd > PRC_NCMDS || inet6ctlerrmap[cmd] == 0))
return;
/* translate addresses into internal form */
sa6 = *(struct sockaddr_in6 *)sa;
if (IN6_IS_ADDR_LINKLOCAL(&sa6.sin6_addr))
sa6.sin6_addr.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index);
if (ip6) {
/*
* XXX: We assume that when ip6 is non NULL,
* M and OFF are valid.
*/
struct in6_addr s;
/* translate addresses into internal form */
memcpy(&s, &ip6->ip6_dst, sizeof(s));
if (IN6_IS_ADDR_LINKLOCAL(&s))
s.s6_addr16[1] = htons(m->m_pkthdr.rcvif->if_index);
if (m->m_len < off + sizeof(th)) {
/*
* this should be rare case,
* so we compromise on this copy...
*/
m_copydata(m, off, sizeof(th), (caddr_t)&th);
thp = &th;
} else
thp = (struct tcphdr *)(mtod(m, caddr_t) + off);
nmatch = in6_pcbnotify(&tcb6, (struct sockaddr *)&sa6,
thp->th_dport, &s, thp->th_sport, cmd, notify);
if (nmatch == 0 && syn_cache_count &&
(inet6ctlerrmap[cmd] == EHOSTUNREACH ||
inet6ctlerrmap[cmd] == ENETUNREACH ||
inet6ctlerrmap[cmd] == EHOSTDOWN)) {
struct sockaddr_in6 sin6;
bzero(&sin6, sizeof(sin6));
sin6.sin6_len = sizeof(sin6);
sin6.sin6_family = AF_INET6;
sin6.sin6_port = thp->th_sport;
sin6.sin6_addr = s;
syn_cache_unreach((struct sockaddr *)&sin6, sa, thp);
}
} else {
(void) in6_pcbnotify(&tcb6, (struct sockaddr *)&sa6, 0,
&zeroin6_addr, 0, cmd, notify);
}
}
#endif
/* assumes that ip header and tcp header are contiguous on mbuf */
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 (sa->sa_family != AF_INET ||
sa->sa_len != sizeof(struct sockaddr_in))
return NULL;
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 && ip->ip_v == 4 && sa->sa_family == AF_INET) {
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)) {
struct sockaddr_in sin;
bzero(&sin, sizeof(sin));
sin.sin_len = sizeof(sin);
sin.sin_family = AF_INET;
sin.sin_port = th->th_sport;
sin.sin_addr = ip->ip_src;
syn_cache_unreach((struct sockaddr *)&sin, sa, th);
}
/* XXX mapped address case */
}
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;
}
#if defined(INET6) && !defined(TCP6)
void
tcp6_quench(in6p, errno)
struct in6pcb *in6p;
int errno;
{
struct tcpcb *tp = in6totcpcb(in6p);
if (tp)
tp->snd_cwnd = tp->t_segsz;
}
#endif
/*
* 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);
}
}
#if defined(INET6) && !defined(TCP6)
void
tcp6_mtudisc(in6p, errno)
struct in6pcb *in6p;
int errno;
{
struct tcpcb *tp = in6totcpcb(in6p);
struct rtentry *rt = in6_pcbrtentry(in6p);
if (tp != 0) {
if (rt != 0) {
/*
* If this was not a host route, remove and realloc.
*/
if ((rt->rt_flags & RTF_HOST) == 0) {
in6_rtchange(in6p, errno);
if ((rt = in6_pcbrtentry(in6p)) == 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);
}
}
#endif
/*
* 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 socket *so;
#if defined(RTV_SPIPE) || defined(RTV_SSTHRESH)
struct rtentry *rt;
#endif
u_long bufsize;
int mss;
so = NULL;
rt = NULL;
if (tp->t_inpcb) {
so = tp->t_inpcb->inp_socket;
#if defined(RTV_SPIPE) || defined(RTV_SSTHRESH)
rt = in_pcbrtentry(tp->t_inpcb);
#endif
}
#ifdef INET6
else if (tp->t_in6pcb) {
so = tp->t_in6pcb->in6p_socket;
#if defined(RTV_SPIPE) || defined(RTV_SSTHRESH)
#ifdef TCP6
rt = NULL;
#else
rt = in6_pcbrtentry(tp->t_in6pcb);
#endif
#endif
}
#endif
/*
* 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);
if (tp->t_inpcb)
mss -= ip_optlen(tp->t_inpcb);
#ifdef INET6
else if (tp->t_in6pcb)
mss -= ip6_optlen(tp->t_in6pcb);
#endif
/*
* 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 socket *so;
#ifdef RTV_RPIPE
struct rtentry *rt;
#endif
u_long bufsize;
so = NULL;
rt = NULL;
if (tp->t_inpcb) {
so = tp->t_inpcb->inp_socket;
#if defined(RTV_RPIPE)
rt = in_pcbrtentry(tp->t_inpcb);
#endif
}
#ifdef INET6
else if (tp->t_in6pcb) {
so = tp->t_in6pcb->in6p_socket;
#if defined(RTV_RPIPE)
#ifdef TCP6
rt = NULL;
#else
rt = in6_pcbrtentry(tp->t_in6pcb);
#endif
#endif
}
#endif
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 = NULL;
int rtt;
if (tp->t_inpcb)
rt = in_pcbrtentry(tp->t_inpcb);
#ifdef INET6
else if (tp->t_in6pcb) {
#ifdef TCP6
rt = NULL;
#else
rt = in6_pcbrtentry(tp->t_in6pcb);
#endif
}
#endif
if (rt == 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;
/*
* 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;
}
#ifdef IPSEC
/* compute ESP/AH header size for TCP, including outer IP header. */
size_t
ipsec4_hdrsiz_tcp(tp)
struct tcpcb *tp;
{
struct inpcb *inp;
size_t hdrsiz;
/* XXX mapped addr case (tp->t_in6pcb) */
if (!tp || !tp->t_template || !(inp = tp->t_inpcb))
return 0;
switch (tp->t_family) {
case AF_INET:
hdrsiz = ipsec4_hdrsiz(tp->t_template, inp);
break;
default:
hdrsiz = 0;
break;
}
return hdrsiz;
}
#if defined(INET6) && !defined(TCP6)
size_t
ipsec6_hdrsiz_tcp(tp)
struct tcpcb *tp;
{
struct in6pcb *in6p;
size_t hdrsiz;
if (!tp || !tp->t_template || !(in6p = tp->t_in6pcb))
return 0;
switch (tp->t_family) {
case AF_INET6:
hdrsiz = ipsec6_hdrsiz(tp->t_template, in6p);
break;
case AF_INET:
/* mapped address case - tricky */
default:
hdrsiz = 0;
break;
}
return hdrsiz;
}
#endif
#endif /*IPSEC*/
/*
* 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;
}
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