/* $OpenBSD: tcp_subr.c,v 1.77 2004/03/02 12:51:12 markus 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef INET6 #include #include #endif /* INET6 */ #ifdef TCP_SIGNATURE #include #endif /* TCP_SIGNATURE */ /* patchable/settable parameters for tcp */ int tcp_mssdflt = TCP_MSS; int tcp_rttdflt = TCPTV_SRTTDFLT / PR_SLOWHZ; /* * Configure kernel with options "TCP_DO_RFC1323=0" to disable RFC1323 stuff. * This is a good idea over slow SLIP/PPP links, because the timestamp * pretty well destroys the VJ compression (any packet with a timestamp * different from the previous one can't be compressed), as well as adding * more overhead. * XXX And it should be a settable per route characteristic (with this just * used as the default). */ #ifndef TCP_DO_RFC1323 #define TCP_DO_RFC1323 1 #endif int tcp_do_rfc1323 = TCP_DO_RFC1323; #ifndef TCP_DO_SACK #ifdef TCP_SACK #define TCP_DO_SACK 1 #else #define TCP_DO_SACK 0 #endif #endif int tcp_do_sack = TCP_DO_SACK; /* RFC 2018 selective ACKs */ int tcp_ack_on_push = 0; /* set to enable immediate ACK-on-PUSH */ int tcp_do_ecn = 0; /* RFC3168 ECN enabled/disabled? */ int tcp_do_rfc3390 = 0; /* RFC3390 Increasing TCP's Initial Window */ u_int32_t tcp_now; #ifndef TCBHASHSIZE #define TCBHASHSIZE 128 #endif int tcbhashsize = TCBHASHSIZE; /* syn hash parameters */ #define TCP_SYN_HASH_SIZE 293 #define TCP_SYN_BUCKET_SIZE 35 int tcp_syn_cache_size = TCP_SYN_HASH_SIZE; int tcp_syn_cache_limit = TCP_SYN_HASH_SIZE*TCP_SYN_BUCKET_SIZE; int tcp_syn_bucket_limit = 3*TCP_SYN_BUCKET_SIZE; struct syn_cache_head tcp_syn_cache[TCP_SYN_HASH_SIZE]; int tcp_reass_limit = NMBCLUSTERS / 2; /* hardlimit for tcpqe_pool */ #ifdef INET6 extern int ip6_defhlim; #endif /* INET6 */ struct pool tcpcb_pool; struct pool tcpqe_pool; #ifdef TCP_SACK struct pool sackhl_pool; #endif struct tcpstat tcpstat; /* tcp statistics */ tcp_seq tcp_iss; /* * Tcp initialization */ void tcp_init() { #ifdef TCP_COMPAT_42 tcp_iss = 1; /* wrong */ #endif /* TCP_COMPAT_42 */ pool_init(&tcpcb_pool, sizeof(struct tcpcb), 0, 0, 0, "tcpcbpl", NULL); pool_init(&tcpqe_pool, sizeof(struct ipqent), 0, 0, 0, "tcpqepl", NULL); pool_sethardlimit(&tcpqe_pool, tcp_reass_limit, NULL, 0); #ifdef TCP_SACK pool_init(&sackhl_pool, sizeof(struct sackhole), 0, 0, 0, "sackhlpl", NULL); #endif /* TCP_SACK */ in_pcbinit(&tcbtable, tcbhashsize); tcp_now = arc4random() / 2; #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(tp) 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*/ #ifdef INET case AF_INET: m->m_len = sizeof(struct ip); break; #endif /* INET */ #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) { #ifdef INET 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)); th->th_sum = in_cksum_phdr(ipovly->ih_src.s_addr, ipovly->ih_dst.s_addr, htons(sizeof (struct tcphdr) + IPPROTO_TCP)); } break; #endif /* INET */ #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, NULL); /*XXX*/ th = (struct tcphdr *)(mtod(m, caddr_t) + sizeof(struct ip6_hdr)); th->th_sum = 0; } 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; 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. */ #ifdef INET6 /* This function looks hairy, because it was so IPv4-dependent. */ #endif /* INET6 */ void tcp_respond(tp, template, m, ack, seq, flags) struct tcpcb *tp; caddr_t template; struct mbuf *m; tcp_seq ack, seq; int flags; { int tlen; int win = 0; struct route *ro = 0; struct tcphdr *th; struct tcpiphdr *ti = (struct tcpiphdr *)template; 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; /* * The route/route6 distinction is meaningless * unless you're allocating space or passing parameters. */ ro = &tp->t_inpcb->inp_route; } else af = (((struct ip *)ti)->ip_v == 6) ? AF_INET6 : AF_INET; if (m == 0) { m = m_gethdr(M_DONTWAIT, MT_HEADER); if (m == NULL) return; #ifdef TCP_COMPAT_42 tlen = 1; #else tlen = 0; #endif m->m_data += max_linkhdr; switch (af) { #ifdef INET6 case AF_INET6: bcopy(ti, mtod(m, caddr_t), sizeof(struct tcphdr) + sizeof(struct ip6_hdr)); break; #endif /* INET6 */ case AF_INET: bcopy(ti, mtod(m, caddr_t), sizeof(struct tcphdr) + sizeof(struct ip)); break; } ti = mtod(m, struct tcpiphdr *); flags = TH_ACK; } else { m_freem(m->m_next); m->m_next = 0; m->m_data = (caddr_t)ti; 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: m->m_len = sizeof(struct tcphdr) + sizeof(struct ip6_hdr); xchg(((struct ip6_hdr *)ti)->ip6_dst, ((struct ip6_hdr *)ti)->ip6_src, struct in6_addr); th = (void *)((caddr_t)ti + sizeof(struct ip6_hdr)); break; #endif /* INET6 */ case AF_INET: m->m_len = sizeof (struct tcpiphdr); xchg(ti->ti_dst.s_addr, ti->ti_src.s_addr, u_int32_t); th = (void *)((caddr_t)ti + sizeof(struct ip)); break; } xchg(th->th_dport, th->th_sport, u_int16_t); #undef xchg } switch (af) { #ifdef INET6 case AF_INET6: tlen += sizeof(struct tcphdr) + sizeof(struct ip6_hdr); th = (struct tcphdr *)((caddr_t)ti + sizeof(struct ip6_hdr)); break; #endif /* INET6 */ case AF_INET: ti->ti_len = htons((u_int16_t)(sizeof (struct tcphdr) + tlen)); tlen += sizeof (struct tcpiphdr); th = (struct tcphdr *)((caddr_t)ti + sizeof(struct ip)); break; } m->m_len = tlen; m->m_pkthdr.len = tlen; m->m_pkthdr.rcvif = (struct ifnet *) 0; 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; switch (af) { #ifdef INET6 case AF_INET6: ((struct ip6_hdr *)ti)->ip6_flow = htonl(0x60000000); ((struct ip6_hdr *)ti)->ip6_nxt = IPPROTO_TCP; ((struct ip6_hdr *)ti)->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, NULL); /*XXX*/ ((struct ip6_hdr *)ti)->ip6_plen = tlen - sizeof(struct ip6_hdr); th->th_sum = 0; th->th_sum = in6_cksum(m, IPPROTO_TCP, sizeof(struct ip6_hdr), ((struct ip6_hdr *)ti)->ip6_plen); HTONS(((struct ip6_hdr *)ti)->ip6_plen); ip6_output(m, tp ? tp->t_inpcb->inp_outputopts6 : NULL, (struct route_in6 *)ro, 0, NULL, NULL); break; #endif /* INET6 */ case AF_INET: bzero(ti->ti_x1, sizeof ti->ti_x1); ti->ti_len = htons((u_short)tlen - sizeof(struct ip)); /* * There's no point deferring to hardware checksum processing * here, as we only send a minimal TCP packet whose checksum * we need to compute in any case. */ th->th_sum = 0; th->th_sum = in_cksum(m, tlen); ((struct ip *)ti)->ip_len = htons(tlen); ((struct ip *)ti)->ip_ttl = ip_defttl; ip_output(m, (void *)NULL, ro, ip_mtudisc ? IP_MTUDISC : 0, (void *)NULL, tp ? tp->t_inpcb : (void *)NULL); } } /* * 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); if (tp == NULL) return ((struct tcpcb *)0); bzero((char *) tp, sizeof(struct tcpcb)); LIST_INIT(&tp->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); #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 + 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; #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(tp, errno) 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.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(struct tcpcb *tp) { struct inpcb *inp = tp->t_inpcb; struct socket *so = inp->inp_socket; #ifdef TCP_SACK struct sackhole *p, *q; #endif #ifdef RTV_RTT struct rtentry *rt; #ifdef INET6 int bound_to_specific = 0; /* I.e. non-default */ /* * This code checks the nature of the route for this connection. * Normally this is done by two simple checks in the next * INET/INET6 ifdef block, but because of two possible lower layers, * that check is done here. * * Perhaps should be doing this only for a RTF_HOST route. */ rt = inp->inp_route.ro_rt; /* Same for route or route6. */ if (tp->pf == PF_INET6) { if (rt) bound_to_specific = !(IN6_IS_ADDR_UNSPECIFIED(& ((struct sockaddr_in6 *)rt_key(rt))->sin6_addr)); } else { if (rt) bound_to_specific = (((struct sockaddr_in *)rt_key(rt))-> sin_addr.s_addr != INADDR_ANY); } #endif /* INET6 */ /* * 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". */ #ifdef INET6 /* * Note that rt and bound_to_specific are set above. */ if (SEQ_LT(tp->iss + so->so_snd.sb_hiwat * 16, tp->snd_max) && rt && bound_to_specific) { #else /* INET6 */ if (SEQ_LT(tp->iss + so->so_snd.sb_hiwat * 16, tp->snd_max) && (rt = inp->inp_route.ro_rt) && satosin(rt_key(rt))->sin_addr.s_addr != INADDR_ANY) { #endif /* INET6 */ u_long i = 0; if ((rt->rt_rmx.rmx_locks & RTV_RTT) == 0) { i = tp->t_srtt * (RTM_RTTUNIT / (PR_SLOWHZ * TCP_RTT_SCALE)); 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_SCALE)); 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_maxseg / 2) / tp->t_maxseg; if (i < 2) i = 2; #ifdef INET6 if (tp->pf == PF_INET6) i *= (u_long)(tp->t_maxseg + sizeof (struct tcphdr) + sizeof(struct ip6_hdr)); else #endif /* INET6 */ i *= (u_long)(tp->t_maxseg + 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); tcp_freeq(tp); tcp_reass_unlock(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 if (tp->t_template) (void) m_free(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(struct tcpcb *tp) { struct ipqent *qe; int rv = 0; while ((qe = LIST_FIRST(&tp->segq)) != NULL) { LIST_REMOVE(qe, ipqe_q); m_freem(qe->ipqe_m); pool_put(&tcpqe_pool, qe); rv = 1; } return (rv); } void tcp_drain() { struct inpcb *inp; /* called at splimp() */ CIRCLEQ_FOREACH(inp, &tcbtable.inpt_queue, inp_queue) { struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; if (tp != NULL) { if (tcp_reass_lock_try(tp) == 0) continue; if (tcp_freeq(tp)) tcpstat.tcps_conndrained++; tcp_reass_unlock(tp); } } } /* * 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(inp, error) struct inpcb *inp; int error; { struct tcpcb *tp = (struct tcpcb *)inp->inp_ppcb; 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(cmd, sa, d) int cmd; struct sockaddr *sa; void *d; { struct tcphdr th; void (*notify)(struct inpcb *, int) = tcp_notify; struct ip6_hdr *ip6; const struct sockaddr_in6 *sa6_src = NULL; struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)sa; struct mbuf *m; int off; struct { u_int16_t th_sport; u_int16_t th_dport; } *thp; if (sa->sa_family != AF_INET6 || sa->sa_len != sizeof(struct sockaddr_in6)) return; if ((unsigned)cmd >= PRC_NCMDS) return; else if (cmd == PRC_QUENCH) { /* XXX there's no PRC_QUENCH in IPv6 */ notify = tcp_quench; } 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); if (cmd == PRC_MSGSIZE) { int valid = 0; /* * Check to see if we have a valid TCP connection * corresponding to the address in the ICMPv6 message * payload. */ if (in6_pcbhashlookup(&tcbtable, &sa6->sin6_addr, th.th_dport, (struct in6_addr *)&sa6_src->sin6_addr, th.th_sport)) valid++; /* * 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, valid); return; } if (in6_pcbnotify(&tcbtable, sa, th.th_dport, (struct sockaddr *)sa6_src, th.th_sport, cmd, NULL, notify) == 0 && syn_cache_count && (inet6ctlerrmap[cmd] == EHOSTUNREACH || inet6ctlerrmap[cmd] == ENETUNREACH || inet6ctlerrmap[cmd] == EHOSTDOWN)) syn_cache_unreach((struct sockaddr *)sa6_src, sa, &th); } else { (void) in6_pcbnotify(&tcbtable, sa, 0, (struct sockaddr *)sa6_src, 0, cmd, NULL, notify); } } #endif void * tcp_ctlinput(cmd, sa, v) int cmd; struct sockaddr *sa; void *v; { struct ip *ip = v; struct tcphdr *th; extern int inetctlerrmap[]; void (*notify)(struct inpcb *, int) = tcp_notify; int errno; if (sa->sa_family != AF_INET) 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) { th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); /* * Verify that the packet in the icmp payload refers * to an existing TCP connection. */ /* * XXX is it possible to get a valid PRC_MSGSIZE error for * a non-established connection? */ if (in_pcbhashlookup(&tcbtable, ip->ip_dst, th->th_dport, ip->ip_src, th->th_sport)) { struct icmp *icp; icp = (struct icmp *)((caddr_t)ip - offsetof(struct icmp, icmp_ip)); /* Calculate new mtu and create corresponding route */ icmp_mtudisc(icp); } 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 NULL; if (ip) { th = (struct tcphdr *)((caddr_t)ip + (ip->ip_hl << 2)); if (in_pcbnotify(&tcbtable, sa, th->th_dport, ip->ip_src, th->th_sport, errno, notify) == 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); } } else in_pcbnotifyall(&tcbtable, sa, errno, notify); return NULL; } /* * When a source quench is received, close congestion window * to 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_maxseg; } #ifdef INET6 /* * Path MTU Discovery handlers. */ void tcp6_mtudisc_callback(faddr) struct in6_addr *faddr; { struct sockaddr_in6 sin6; bzero(&sin6, sizeof(sin6)); sin6.sin6_family = AF_INET6; sin6.sin6_len = sizeof(struct sockaddr_in6); sin6.sin6_addr = *faddr; (void) in6_pcbnotify(&tcbtable, (struct sockaddr *)&sin6, 0, (struct sockaddr *)&sa6_any, 0, 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(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; } if (rt->rt_rmx.rmx_mtu != 0) { /* also takes care of congestion window */ tcp_mss(tp, -1); } } /* * Resend unacknowledged packets. */ tp->snd_nxt = tp->snd_una; tcp_output(tp); } } void tcp_mtudisc_increase(inp, errno) 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); } } #ifdef TCP_SIGNATURE int tcp_signature_tdb_attach() { return (0); } int tcp_signature_tdb_init(tdbp, xsp, ii) 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_DONTWAIT); 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(tdbp) struct tdb *tdbp; { if (tdbp->tdb_amxkey) { bzero(tdbp->tdb_amxkey, tdbp->tdb_amxkeylen); free(tdbp->tdb_amxkey, M_XDATA); tdbp->tdb_amxkey = NULL; } return (0); } int tcp_signature_tdb_input(m, tdbp, skip, protoff) struct mbuf *m; struct tdb *tdbp; int skip, protoff; { return (0); } int tcp_signature_tdb_output(m, tdbp, mp, skip, protoff) struct mbuf *m; struct tdb *tdbp; struct mbuf **mp; int skip, protoff; { return (EINVAL); } int tcp_signature_apply(fstate, data, len) caddr_t fstate; caddr_t data; unsigned int len; { MD5Update((MD5_CTX *)fstate, (char *)data, len); return 0; } #endif /* TCP_SIGNATURE */ #define TCP_RNDISS_ROUNDS 16 #define TCP_RNDISS_OUT 7200 #define TCP_RNDISS_MAX 30000 u_int8_t tcp_rndiss_sbox[128]; u_int16_t tcp_rndiss_msb; u_int16_t tcp_rndiss_cnt; long tcp_rndiss_reseed; u_int16_t tcp_rndiss_encrypt(val) u_int16_t val; { u_int16_t sum = 0, i; for (i = 0; i < TCP_RNDISS_ROUNDS; i++) { sum += 0x79b9; val ^= ((u_int16_t)tcp_rndiss_sbox[(val^sum) & 0x7f]) << 7; val = ((val & 0xff) << 7) | (val >> 8); } return val; } void tcp_rndiss_init() { get_random_bytes(tcp_rndiss_sbox, sizeof(tcp_rndiss_sbox)); tcp_rndiss_reseed = time.tv_sec + TCP_RNDISS_OUT; tcp_rndiss_msb = tcp_rndiss_msb == 0x8000 ? 0 : 0x8000; tcp_rndiss_cnt = 0; } tcp_seq tcp_rndiss_next() { if (tcp_rndiss_cnt >= TCP_RNDISS_MAX || time.tv_sec > tcp_rndiss_reseed) tcp_rndiss_init(); /* (arc4random() & 0x7fff) ensures a 32768 byte gap between ISS */ return ((tcp_rndiss_encrypt(tcp_rndiss_cnt++) | tcp_rndiss_msb) <<16) | (arc4random() & 0x7fff); }