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|
/* $OpenBSD: tcp_subr.c,v 1.162 2017/05/04 15:00:24 bluhm Exp $ */
/* $NetBSD: tcp_subr.c,v 1.22 1996/02/13 23:44:00 christos Exp $ */
/*
* Copyright (c) 1982, 1986, 1988, 1990, 1993
* 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. 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.
*
* @(#)COPYRIGHT 1.1 (NRL) 17 January 1995
*
* NRL grants permission for redistribution and use in source and binary
* forms, with or without modification, of the software and documentation
* created at NRL 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 acknowledgements:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* This product includes software developed at the Information
* Technology Division, US Naval Research Laboratory.
* 4. Neither the name of the NRL nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THE SOFTWARE PROVIDED BY NRL IS PROVIDED BY NRL 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 NRL 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.
*
* The views and conclusions contained in the software and documentation
* are those of the authors and should not be interpreted as representing
* official policies, either expressed or implied, of the US Naval
* Research Laboratory (NRL).
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/timeout.h>
#include <sys/protosw.h>
#include <sys/kernel.h>
#include <sys/pool.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/ip_var.h>
#include <netinet/ip_icmp.h>
#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 INET6
#include <netinet6/ip6protosw.h>
#endif /* INET6 */
#include <crypto/md5.h>
#include <crypto/sha2.h>
/* patchable/settable parameters for tcp */
int tcp_mssdflt = TCP_MSS;
int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ;
/* values controllable via sysctl */
int tcp_do_rfc1323 = 1;
#ifdef TCP_SACK
int tcp_do_sack = 1; /* RFC 2018 selective ACKs */
#endif
int tcp_ack_on_push = 0; /* set to enable immediate ACK-on-PUSH */
#ifdef TCP_ECN
int tcp_do_ecn = 0; /* RFC3168 ECN enabled/disabled? */
#endif
int tcp_do_rfc3390 = 2; /* Increase TCP's Initial Window to 10*mss */
u_int32_t tcp_now = 1;
#ifndef TCB_INITIAL_HASH_SIZE
#define TCB_INITIAL_HASH_SIZE 128
#endif
int tcp_reass_limit = NMBCLUSTERS / 8; /* hardlimit for tcpqe_pool */
#ifdef TCP_SACK
int tcp_sackhole_limit = 32*1024; /* hardlimit for sackhl_pool */
#endif
struct pool tcpcb_pool;
struct pool tcpqe_pool;
#ifdef TCP_SACK
struct pool sackhl_pool;
#endif
struct cpumem *tcpcounters; /* tcp statistics */
tcp_seq tcp_iss;
/*
* Tcp initialization
*/
void
tcp_init(void)
{
tcp_iss = 1; /* wrong */
pool_init(&tcpcb_pool, sizeof(struct tcpcb), 0, IPL_SOFTNET, 0,
"tcpcb", NULL);
pool_init(&tcpqe_pool, sizeof(struct tcpqent), 0, IPL_SOFTNET, 0,
"tcpqe", NULL);
pool_sethardlimit(&tcpqe_pool, tcp_reass_limit, NULL, 0);
#ifdef TCP_SACK
pool_init(&sackhl_pool, sizeof(struct sackhole), 0, IPL_SOFTNET, 0,
"sackhl", NULL);
pool_sethardlimit(&sackhl_pool, tcp_sackhole_limit, NULL, 0);
#endif /* TCP_SACK */
in_pcbinit(&tcbtable, TCB_INITIAL_HASH_SIZE);
tcpcounters = counters_alloc(tcps_ncounters);
#ifdef INET6
/*
* Since sizeof(struct ip6_hdr) > sizeof(struct ip), we
* do max length checks/computations only on the former.
*/
if (max_protohdr < (sizeof(struct ip6_hdr) + sizeof(struct tcphdr)))
max_protohdr = (sizeof(struct ip6_hdr) + sizeof(struct tcphdr));
if ((max_linkhdr + sizeof(struct ip6_hdr) + sizeof(struct tcphdr)) >
MHLEN)
panic("tcp_init");
icmp6_mtudisc_callback_register(tcp6_mtudisc_callback);
#endif /* INET6 */
/* Initialize the compressed state engine. */
syn_cache_init();
/* Initialize timer state. */
tcp_timer_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.
*
* To support IPv6 in addition to IPv4 and considering that the sizes of
* the IPv4 and IPv6 headers are not the same, we now use a separate pointer
* for the TCP header. Also, we made the former tcpiphdr header pointer
* into just an IP overlay pointer, with casting as appropriate for v6. rja
*/
struct mbuf *
tcp_template(struct tcpcb *tp)
{
struct inpcb *inp = tp->t_inpcb;
struct mbuf *m;
struct tcphdr *th;
if ((m = tp->t_template) == 0) {
m = m_get(M_DONTWAIT, MT_HEADER);
if (m == NULL)
return (0);
switch (tp->pf) {
case 0: /*default to PF_INET*/
case AF_INET:
m->m_len = sizeof(struct ip);
break;
#ifdef INET6
case AF_INET6:
m->m_len = sizeof(struct ip6_hdr);
break;
#endif /* INET6 */
}
m->m_len += sizeof (struct tcphdr);
/*
* The link header, network header, TCP header, and TCP options
* all must fit in this mbuf. For now, assume the worst case of
* TCP options size. Eventually, compute this from tp flags.
*/
if (m->m_len + MAX_TCPOPTLEN + max_linkhdr >= MHLEN) {
MCLGET(m, M_DONTWAIT);
if ((m->m_flags & M_EXT) == 0) {
m_free(m);
return (0);
}
}
}
switch(tp->pf) {
case AF_INET:
{
struct ipovly *ipovly;
ipovly = mtod(m, struct ipovly *);
bzero(ipovly->ih_x1, sizeof ipovly->ih_x1);
ipovly->ih_pr = IPPROTO_TCP;
ipovly->ih_len = htons(sizeof (struct tcphdr));
ipovly->ih_src = inp->inp_laddr;
ipovly->ih_dst = inp->inp_faddr;
th = (struct tcphdr *)(mtod(m, caddr_t) +
sizeof(struct ip));
}
break;
#ifdef INET6
case AF_INET6:
{
struct ip6_hdr *ip6;
ip6 = mtod(m, struct ip6_hdr *);
ip6->ip6_src = inp->inp_laddr6;
ip6->ip6_dst = inp->inp_faddr6;
ip6->ip6_flow = htonl(0x60000000) |
(inp->inp_flowinfo & IPV6_FLOWLABEL_MASK);
ip6->ip6_nxt = IPPROTO_TCP;
ip6->ip6_plen = htons(sizeof(struct tcphdr)); /*XXX*/
ip6->ip6_hlim = in6_selecthlim(inp); /*XXX*/
th = (struct tcphdr *)(mtod(m, caddr_t) +
sizeof(struct ip6_hdr));
}
break;
#endif /* INET6 */
}
th->th_sport = inp->inp_lport;
th->th_dport = inp->inp_fport;
th->th_seq = 0;
th->th_ack = 0;
th->th_x2 = 0;
th->th_off = 5;
th->th_flags = 0;
th->th_win = 0;
th->th_urp = 0;
th->th_sum = 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.
*/
void
tcp_respond(struct tcpcb *tp, caddr_t template, struct tcphdr *th0,
tcp_seq ack, tcp_seq seq, int flags, u_int rtableid)
{
int tlen;
int win = 0;
struct mbuf *m = NULL;
struct tcphdr *th;
struct ip *ip;
#ifdef INET6
struct ip6_hdr *ip6;
#endif
int af; /* af on wire */
if (tp) {
win = sbspace(&tp->t_inpcb->inp_socket->so_rcv);
/*
* If this is called with an unconnected
* socket/tp/pcb (tp->pf is 0), we lose.
*/
af = tp->pf;
} else
af = (((struct ip *)template)->ip_v == 6) ? AF_INET6 : AF_INET;
m = m_gethdr(M_DONTWAIT, MT_HEADER);
if (m == NULL)
return;
m->m_data += max_linkhdr;
tlen = 0;
#define xchg(a,b,type) do { type t; t=a; a=b; b=t; } while (0)
switch (af) {
#ifdef INET6
case AF_INET6:
ip6 = mtod(m, struct ip6_hdr *);
th = (struct tcphdr *)(ip6 + 1);
tlen = sizeof(*ip6) + sizeof(*th);
if (th0) {
bcopy(template, ip6, sizeof(*ip6));
bcopy(th0, th, sizeof(*th));
xchg(ip6->ip6_dst, ip6->ip6_src, struct in6_addr);
} else {
bcopy(template, ip6, tlen);
}
break;
#endif /* INET6 */
case AF_INET:
ip = mtod(m, struct ip *);
th = (struct tcphdr *)(ip + 1);
tlen = sizeof(*ip) + sizeof(*th);
if (th0) {
bcopy(template, ip, sizeof(*ip));
bcopy(th0, th, sizeof(*th));
xchg(ip->ip_dst.s_addr, ip->ip_src.s_addr, u_int32_t);
} else {
bcopy(template, ip, tlen);
}
break;
}
if (th0)
xchg(th->th_dport, th->th_sport, u_int16_t);
else
flags = TH_ACK;
#undef xchg
th->th_seq = htonl(seq);
th->th_ack = htonl(ack);
th->th_x2 = 0;
th->th_off = sizeof (struct tcphdr) >> 2;
th->th_flags = flags;
if (tp)
win >>= tp->rcv_scale;
if (win > TCP_MAXWIN)
win = TCP_MAXWIN;
th->th_win = htons((u_int16_t)win);
th->th_urp = 0;
if (tp && (tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP &&
(flags & TH_RST) == 0 && (tp->t_flags & TF_RCVD_TSTMP)) {
u_int32_t *lp = (u_int32_t *)(th + 1);
/* Form timestamp option as shown in appendix A of RFC 1323. */
*lp++ = htonl(TCPOPT_TSTAMP_HDR);
*lp++ = htonl(tcp_now + tp->ts_modulate);
*lp = htonl(tp->ts_recent);
tlen += TCPOLEN_TSTAMP_APPA;
th->th_off = (sizeof(struct tcphdr) + TCPOLEN_TSTAMP_APPA) >> 2;
}
m->m_len = tlen;
m->m_pkthdr.len = tlen;
m->m_pkthdr.ph_ifidx = 0;
m->m_pkthdr.csum_flags |= M_TCP_CSUM_OUT;
/* force routing table */
if (tp)
m->m_pkthdr.ph_rtableid = tp->t_inpcb->inp_rtableid;
else
m->m_pkthdr.ph_rtableid = rtableid;
switch (af) {
#ifdef INET6
case AF_INET6:
ip6->ip6_flow = htonl(0x60000000);
ip6->ip6_nxt = IPPROTO_TCP;
ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL); /*XXX*/
ip6->ip6_plen = tlen - sizeof(struct ip6_hdr);
ip6->ip6_plen = htons(ip6->ip6_plen);
ip6_output(m, tp ? tp->t_inpcb->inp_outputopts6 : NULL,
tp ? &tp->t_inpcb->inp_route6 : NULL,
0, NULL,
tp ? tp->t_inpcb : NULL);
break;
#endif /* INET6 */
case AF_INET:
ip->ip_len = htons(tlen);
ip->ip_ttl = ip_defttl;
ip->ip_tos = 0;
ip_output(m, NULL,
tp ? &tp->t_inpcb->inp_route : NULL,
ip_mtudisc ? IP_MTUDISC : 0, NULL,
tp ? tp->t_inpcb : NULL, 0);
break;
}
}
/*
* Create a new TCP control block, making an
* empty reassembly queue and hooking it to the argument
* protocol control block.
*/
struct tcpcb *
tcp_newtcpcb(struct inpcb *inp)
{
struct tcpcb *tp;
int i;
tp = pool_get(&tcpcb_pool, PR_NOWAIT|PR_ZERO);
if (tp == NULL)
return (NULL);
TAILQ_INIT(&tp->t_segq);
tp->t_maxseg = tcp_mssdflt;
tp->t_maxopd = 0;
TCP_INIT_DELACK(tp);
for (i = 0; i < TCPT_NTIMERS; i++)
TCP_TIMER_INIT(tp, i);
timeout_set(&tp->t_reap_to, tcp_reaper, tp);
#ifdef TCP_SACK
tp->sack_enable = tcp_do_sack;
#endif
tp->t_flags = tcp_do_rfc1323 ? (TF_REQ_SCALE|TF_REQ_TSTMP) : 0;
tp->t_inpcb = inp;
/*
* 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 + TCP_RTT_BASE_SHIFT - 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;
tp->t_pmtud_mtu_sent = 0;
tp->t_pmtud_mss_acked = 0;
#ifdef INET6
/* we disallow IPv4 mapped address completely. */
if ((inp->inp_flags & INP_IPV6) == 0)
tp->pf = PF_INET;
else
tp->pf = PF_INET6;
#else
tp->pf = PF_INET;
#endif
#ifdef INET6
if (inp->inp_flags & INP_IPV6)
inp->inp_ipv6.ip6_hlim = ip6_defhlim;
else
#endif /* INET6 */
inp->inp_ip.ip_ttl = ip_defttl;
inp->inp_ppcb = (caddr_t)tp;
return (tp);
}
/*
* Drop a TCP connection, reporting
* the specified error. If connection is synchronized,
* then send a RST to peer.
*/
struct tcpcb *
tcp_drop(struct tcpcb *tp, int errno)
{
struct socket *so = tp->t_inpcb->inp_socket;
if (TCPS_HAVERCVDSYN(tp->t_state)) {
tp->t_state = TCPS_CLOSED;
(void) tcp_output(tp);
tcpstat_inc(tcps_drops);
} else
tcpstat_inc(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(struct tcpcb *tp)
{
struct inpcb *inp = tp->t_inpcb;
struct socket *so = inp->inp_socket;
#ifdef TCP_SACK
struct sackhole *p, *q;
#endif
/* free the reassembly queue, if any */
tcp_freeq(tp);
tcp_canceltimers(tp);
TCP_CLEAR_DELACK(tp);
syn_cache_cleanup(tp);
#ifdef TCP_SACK
/* Free SACK holes. */
q = p = tp->snd_holes;
while (p != 0) {
q = p->next;
pool_put(&sackhl_pool, p);
p = q;
}
#endif
m_free(tp->t_template);
tp->t_flags |= TF_DEAD;
timeout_add(&tp->t_reap_to, 0);
inp->inp_ppcb = 0;
soisdisconnected(so);
in_pcbdetach(inp);
return (NULL);
}
void
tcp_reaper(void *arg)
{
struct tcpcb *tp = arg;
pool_put(&tcpcb_pool, tp);
tcpstat_inc(tcps_closed);
}
int
tcp_freeq(struct tcpcb *tp)
{
struct tcpqent *qe;
int rv = 0;
while ((qe = TAILQ_FIRST(&tp->t_segq)) != NULL) {
TAILQ_REMOVE(&tp->t_segq, qe, tcpqe_q);
m_freem(qe->tcpqe_m);
pool_put(&tcpqe_pool, qe);
rv = 1;
}
return (rv);
}
/*
* Compute proper scaling value for receiver window from buffer space
*/
void
tcp_rscale(struct tcpcb *tp, u_long hiwat)
{
tp->request_r_scale = 0;
while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
TCP_MAXWIN << tp->request_r_scale < hiwat)
tp->request_r_scale++;
}
/*
* 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(struct inpcb *inp, int error)
{
struct tcpcb *tp = intotcpcb(inp);
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);
}
#ifdef INET6
void
tcp6_ctlinput(int cmd, struct sockaddr *sa, u_int rdomain, void *d)
{
struct tcphdr th;
struct tcpcb *tp;
void (*notify)(struct inpcb *, int) = tcp_notify;
struct ip6_hdr *ip6;
const struct sockaddr_in6 *sa6_src = NULL;
struct sockaddr_in6 *sa6 = satosin6(sa);
struct inpcb *inp;
struct mbuf *m;
tcp_seq seq;
int off;
struct {
u_int16_t th_sport;
u_int16_t th_dport;
u_int32_t th_seq;
} *thp;
if (sa->sa_family != AF_INET6 ||
sa->sa_len != sizeof(struct sockaddr_in6) ||
IN6_IS_ADDR_UNSPECIFIED(&sa6->sin6_addr) ||
IN6_IS_ADDR_V4MAPPED(&sa6->sin6_addr))
return;
if ((unsigned)cmd >= PRC_NCMDS)
return;
else if (cmd == PRC_QUENCH) {
/*
* Don't honor ICMP Source Quench messages meant for
* TCP connections.
*/
/* XXX there's no PRC_QUENCH in IPv6 */
return;
} else if (PRC_IS_REDIRECT(cmd))
notify = in_rtchange, d = NULL;
else if (cmd == PRC_MSGSIZE)
; /* special code is present, see below */
else if (cmd == PRC_HOSTDEAD)
d = NULL;
else if (inet6ctlerrmap[cmd] == 0)
return;
/* if the parameter is from icmp6, decode it. */
if (d != NULL) {
struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d;
m = ip6cp->ip6c_m;
ip6 = ip6cp->ip6c_ip6;
off = ip6cp->ip6c_off;
sa6_src = ip6cp->ip6c_src;
} else {
m = NULL;
ip6 = NULL;
sa6_src = &sa6_any;
}
if (ip6) {
/*
* XXX: We assume that when ip6 is non NULL,
* M and OFF are valid.
*/
/* check if we can safely examine src and dst ports */
if (m->m_pkthdr.len < off + sizeof(*thp))
return;
bzero(&th, sizeof(th));
#ifdef DIAGNOSTIC
if (sizeof(*thp) > sizeof(th))
panic("assumption failed in tcp6_ctlinput");
#endif
m_copydata(m, off, sizeof(*thp), (caddr_t)&th);
/*
* Check to see if we have a valid TCP connection
* corresponding to the address in the ICMPv6 message
* payload.
*/
inp = in6_pcbhashlookup(&tcbtable, &sa6->sin6_addr,
th.th_dport, &sa6_src->sin6_addr, th.th_sport, rdomain);
if (cmd == PRC_MSGSIZE) {
/*
* Depending on the value of "valid" and routing table
* size (mtudisc_{hi,lo}wat), we will:
* - recalcurate the new MTU and create the
* corresponding routing entry, or
* - ignore the MTU change notification.
*/
icmp6_mtudisc_update((struct ip6ctlparam *)d, inp != NULL);
return;
}
if (inp) {
seq = ntohl(th.th_seq);
if (inp->inp_socket &&
(tp = intotcpcb(inp)) &&
SEQ_GEQ(seq, tp->snd_una) &&
SEQ_LT(seq, tp->snd_max))
notify(inp, inet6ctlerrmap[cmd]);
} else if (inet6ctlerrmap[cmd] == EHOSTUNREACH ||
inet6ctlerrmap[cmd] == ENETUNREACH ||
inet6ctlerrmap[cmd] == EHOSTDOWN)
syn_cache_unreach((struct sockaddr *)sa6_src,
sa, &th, rdomain);
} else {
(void) in6_pcbnotify(&tcbtable, sa6, 0,
sa6_src, 0, rdomain, cmd, NULL, notify);
}
}
#endif
void
tcp_ctlinput(int cmd, struct sockaddr *sa, u_int rdomain, void *v)
{
struct ip *ip = v;
struct tcphdr *th;
struct tcpcb *tp;
struct inpcb *inp;
struct in_addr faddr;
tcp_seq seq;
u_int mtu;
void (*notify)(struct inpcb *, int) = tcp_notify;
int errno;
if (sa->sa_family != AF_INET)
return;
faddr = satosin(sa)->sin_addr;
if (faddr.s_addr == INADDR_ANY)
return;
if ((unsigned)cmd >= PRC_NCMDS)
return;
errno = inetctlerrmap[cmd];
if (cmd == PRC_QUENCH)
/*
* Don't honor ICMP Source Quench messages meant for
* TCP connections.
*/
return;
else if (PRC_IS_REDIRECT(cmd))
notify = in_rtchange, ip = 0;
else if (cmd == PRC_MSGSIZE && ip_mtudisc && ip) {
/*
* Verify that the packet in the icmp payload refers
* to an existing TCP connection.
*/
th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2));
seq = ntohl(th->th_seq);
inp = in_pcbhashlookup(&tcbtable,
ip->ip_dst, th->th_dport, ip->ip_src, th->th_sport,
rdomain);
if (inp && (tp = intotcpcb(inp)) &&
SEQ_GEQ(seq, tp->snd_una) &&
SEQ_LT(seq, tp->snd_max)) {
struct icmp *icp;
icp = (struct icmp *)((caddr_t)ip -
offsetof(struct icmp, icmp_ip));
/*
* If the ICMP message advertises a Next-Hop MTU
* equal or larger than the maximum packet size we have
* ever sent, drop the message.
*/
mtu = (u_int)ntohs(icp->icmp_nextmtu);
if (mtu >= tp->t_pmtud_mtu_sent)
return;
if (mtu >= tcp_hdrsz(tp) + tp->t_pmtud_mss_acked) {
/*
* Calculate new MTU, and create corresponding
* route (traditional PMTUD).
*/
tp->t_flags &= ~TF_PMTUD_PEND;
icmp_mtudisc(icp, inp->inp_rtableid);
} else {
/*
* Record the information got in the ICMP
* message; act on it later.
* If we had already recorded an ICMP message,
* replace the old one only if the new message
* refers to an older TCP segment
*/
if (tp->t_flags & TF_PMTUD_PEND) {
if (SEQ_LT(tp->t_pmtud_th_seq, seq))
return;
} else
tp->t_flags |= TF_PMTUD_PEND;
tp->t_pmtud_th_seq = seq;
tp->t_pmtud_nextmtu = icp->icmp_nextmtu;
tp->t_pmtud_ip_len = icp->icmp_ip.ip_len;
tp->t_pmtud_ip_hl = icp->icmp_ip.ip_hl;
return;
}
} else {
/* ignore if we don't have a matching connection */
return;
}
notify = tcp_mtudisc, ip = 0;
} else if (cmd == PRC_MTUINC)
notify = tcp_mtudisc_increase, ip = 0;
else if (cmd == PRC_HOSTDEAD)
ip = 0;
else if (errno == 0)
return;
if (ip) {
th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2));
inp = in_pcbhashlookup(&tcbtable,
ip->ip_dst, th->th_dport, ip->ip_src, th->th_sport,
rdomain);
if (inp) {
seq = ntohl(th->th_seq);
if (inp->inp_socket &&
(tp = intotcpcb(inp)) &&
SEQ_GEQ(seq, tp->snd_una) &&
SEQ_LT(seq, tp->snd_max))
notify(inp, errno);
} else if (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(sintosa(&sin), sa, th, rdomain);
}
} else
in_pcbnotifyall(&tcbtable, sa, rdomain, errno, notify);
}
#ifdef INET6
/*
* Path MTU Discovery handlers.
*/
void
tcp6_mtudisc_callback(struct sockaddr_in6 *sin6, u_int rdomain)
{
(void) in6_pcbnotify(&tcbtable, sin6, 0,
&sa6_any, 0, rdomain, PRC_MSGSIZE, NULL, tcp_mtudisc);
}
#endif /* INET6 */
/*
* 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(struct inpcb *inp, int errno)
{
struct tcpcb *tp = intotcpcb(inp);
struct rtentry *rt = in_pcbrtentry(inp);
int change = 0;
if (tp != 0) {
int orig_maxseg = tp->t_maxseg;
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;
}
if (orig_maxseg != tp->t_maxseg ||
(rt->rt_locks & RTV_MTU))
change = 1;
}
tcp_mss(tp, -1);
/*
* Resend unacknowledged packets
*/
tp->snd_nxt = tp->snd_una;
if (change || errno > 0)
tcp_output(tp);
}
}
void
tcp_mtudisc_increase(struct inpcb *inp, int errno)
{
struct tcpcb *tp = intotcpcb(inp);
struct rtentry *rt = in_pcbrtentry(inp);
if (tp != 0 && rt != 0) {
/*
* If this was a host route, remove and realloc.
*/
if (rt->rt_flags & RTF_HOST)
in_rtchange(inp, errno);
/* also takes care of congestion window */
tcp_mss(tp, -1);
}
}
/*
* Generate new ISNs with a method based on RFC1948
*/
#define TCP_ISS_CONN_INC 4096
int tcp_secret_init;
u_char tcp_secret[16];
SHA2_CTX tcp_secret_ctx;
void
tcp_set_iss_tsm(struct tcpcb *tp)
{
SHA2_CTX ctx;
union {
uint8_t bytes[SHA512_DIGEST_LENGTH];
uint32_t words[2];
} digest;
u_int rdomain = rtable_l2(tp->t_inpcb->inp_rtableid);
if (tcp_secret_init == 0) {
arc4random_buf(tcp_secret, sizeof(tcp_secret));
SHA512Init(&tcp_secret_ctx);
SHA512Update(&tcp_secret_ctx, tcp_secret, sizeof(tcp_secret));
tcp_secret_init = 1;
}
ctx = tcp_secret_ctx;
SHA512Update(&ctx, &rdomain, sizeof(rdomain));
SHA512Update(&ctx, &tp->t_inpcb->inp_lport, sizeof(u_short));
SHA512Update(&ctx, &tp->t_inpcb->inp_fport, sizeof(u_short));
if (tp->pf == AF_INET6) {
SHA512Update(&ctx, &tp->t_inpcb->inp_laddr6,
sizeof(struct in6_addr));
SHA512Update(&ctx, &tp->t_inpcb->inp_faddr6,
sizeof(struct in6_addr));
} else {
SHA512Update(&ctx, &tp->t_inpcb->inp_laddr,
sizeof(struct in_addr));
SHA512Update(&ctx, &tp->t_inpcb->inp_faddr,
sizeof(struct in_addr));
}
SHA512Final(digest.bytes, &ctx);
tcp_iss += TCP_ISS_CONN_INC;
tp->iss = digest.words[0] + tcp_iss;
tp->ts_modulate = digest.words[1];
}
#ifdef TCP_SIGNATURE
int
tcp_signature_tdb_attach(void)
{
return (0);
}
int
tcp_signature_tdb_init(struct tdb *tdbp, struct xformsw *xsp,
struct ipsecinit *ii)
{
if ((ii->ii_authkeylen < 1) || (ii->ii_authkeylen > 80))
return (EINVAL);
tdbp->tdb_amxkey = malloc(ii->ii_authkeylen, M_XDATA, M_NOWAIT);
if (tdbp->tdb_amxkey == NULL)
return (ENOMEM);
bcopy(ii->ii_authkey, tdbp->tdb_amxkey, ii->ii_authkeylen);
tdbp->tdb_amxkeylen = ii->ii_authkeylen;
return (0);
}
int
tcp_signature_tdb_zeroize(struct tdb *tdbp)
{
if (tdbp->tdb_amxkey) {
explicit_bzero(tdbp->tdb_amxkey, tdbp->tdb_amxkeylen);
free(tdbp->tdb_amxkey, M_XDATA, 0);
tdbp->tdb_amxkey = NULL;
}
return (0);
}
int
tcp_signature_tdb_input(struct mbuf *m, struct tdb *tdbp, int skip, int protoff)
{
return (0);
}
int
tcp_signature_tdb_output(struct mbuf *m, struct tdb *tdbp, struct mbuf **mp,
int skip, int protoff)
{
return (EINVAL);
}
int
tcp_signature_apply(caddr_t fstate, caddr_t data, unsigned int len)
{
MD5Update((MD5_CTX *)fstate, (char *)data, len);
return 0;
}
int
tcp_signature(struct tdb *tdb, int af, struct mbuf *m, struct tcphdr *th,
int iphlen, int doswap, char *sig)
{
MD5_CTX ctx;
int len;
struct tcphdr th0;
MD5Init(&ctx);
switch(af) {
case 0:
case AF_INET: {
struct ippseudo ippseudo;
struct ip *ip;
ip = mtod(m, struct ip *);
ippseudo.ippseudo_src = ip->ip_src;
ippseudo.ippseudo_dst = ip->ip_dst;
ippseudo.ippseudo_pad = 0;
ippseudo.ippseudo_p = IPPROTO_TCP;
ippseudo.ippseudo_len = htons(m->m_pkthdr.len - iphlen);
MD5Update(&ctx, (char *)&ippseudo,
sizeof(struct ippseudo));
break;
}
#ifdef INET6
case AF_INET6: {
struct ip6_hdr_pseudo ip6pseudo;
struct ip6_hdr *ip6;
ip6 = mtod(m, struct ip6_hdr *);
bzero(&ip6pseudo, sizeof(ip6pseudo));
ip6pseudo.ip6ph_src = ip6->ip6_src;
ip6pseudo.ip6ph_dst = ip6->ip6_dst;
in6_clearscope(&ip6pseudo.ip6ph_src);
in6_clearscope(&ip6pseudo.ip6ph_dst);
ip6pseudo.ip6ph_nxt = IPPROTO_TCP;
ip6pseudo.ip6ph_len = htonl(m->m_pkthdr.len - iphlen);
MD5Update(&ctx, (char *)&ip6pseudo,
sizeof(ip6pseudo));
break;
}
#endif
}
th0 = *th;
th0.th_sum = 0;
if (doswap) {
th0.th_seq = htonl(th0.th_seq);
th0.th_ack = htonl(th0.th_ack);
th0.th_win = htons(th0.th_win);
th0.th_urp = htons(th0.th_urp);
}
MD5Update(&ctx, (char *)&th0, sizeof(th0));
len = m->m_pkthdr.len - iphlen - th->th_off * sizeof(uint32_t);
if (len > 0 &&
m_apply(m, iphlen + th->th_off * sizeof(uint32_t), len,
tcp_signature_apply, (caddr_t)&ctx))
return (-1);
MD5Update(&ctx, tdb->tdb_amxkey, tdb->tdb_amxkeylen);
MD5Final(sig, &ctx);
return (0);
}
#endif /* TCP_SIGNATURE */
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