/* $OpenBSD: ip_input.c,v 1.9 1996/03/03 22:30:37 niklas Exp $ */ /* $NetBSD: ip_input.c,v 1.28 1996/02/13 23:42:37 christos Exp $ */ /* * Copyright (c) 1982, 1986, 1988, 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. 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. * * @(#)ip_input.c 8.2 (Berkeley) 1/4/94 */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifndef IPFORWARDING #ifdef GATEWAY #define IPFORWARDING 1 /* forward IP packets not for us */ #else /* GATEWAY */ #define IPFORWARDING 0 /* don't forward IP packets not for us */ #endif /* GATEWAY */ #endif /* IPFORWARDING */ #ifndef IPSENDREDIRECTS #define IPSENDREDIRECTS 1 #endif /* * Note: DIRECTED_BROADCAST is handled this way so that previous * configuration using this option will Just Work. */ #ifndef IPDIRECTEDBCAST #ifdef DIRECTED_BROADCAST #define IPDIRECTEDBCAST 1 #else #define IPDIRECTEDBCAST 0 #endif /* DIRECTED_BROADCAST */ #endif /* IPDIRECTEDBCAST */ int ipforwarding = IPFORWARDING; int ipsendredirects = IPSENDREDIRECTS; int ip_dosourceroute = 0; /* no src-routing unless sysctl'd to enable */ int ip_defttl = IPDEFTTL; int ip_directedbcast = IPDIRECTEDBCAST; #ifdef DIAGNOSTIC int ipprintfs = 0; #endif extern struct domain inetdomain; extern struct protosw inetsw[]; u_char ip_protox[IPPROTO_MAX]; int ipqmaxlen = IFQ_MAXLEN; struct in_ifaddrhead in_ifaddr; struct ifqueue ipintrq; char * inet_ntoa(ina) struct in_addr ina; { static char buf[4*sizeof "123"]; unsigned char *ucp = (unsigned char *)&ina; sprintf(buf, "%d.%d.%d.%d", ucp[0] & 0xff, ucp[1] & 0xff, ucp[2] & 0xff, ucp[3] & 0xff); return (buf); } /* * We need to save the IP options in case a protocol wants to respond * to an incoming packet over the same route if the packet got here * using IP source routing. This allows connection establishment and * maintenance when the remote end is on a network that is not known * to us. */ int ip_nhops = 0; static struct ip_srcrt { struct in_addr dst; /* final destination */ char nop; /* one NOP to align */ char srcopt[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN and OFFSET */ struct in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)]; } ip_srcrt; static void save_rte __P((u_char *, struct in_addr)); /* * IP initialization: fill in IP protocol switch table. * All protocols not implemented in kernel go to raw IP protocol handler. */ void ip_init() { register struct protosw *pr; register int i; pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW); if (pr == 0) panic("ip_init"); for (i = 0; i < IPPROTO_MAX; i++) ip_protox[i] = pr - inetsw; for (pr = inetdomain.dom_protosw; pr < inetdomain.dom_protoswNPROTOSW; pr++) if (pr->pr_domain->dom_family == PF_INET && pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW) ip_protox[pr->pr_protocol] = pr - inetsw; LIST_INIT(&ipq); ip_id = time.tv_sec & 0xffff; ipintrq.ifq_maxlen = ipqmaxlen; TAILQ_INIT(&in_ifaddr); } struct sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET }; struct route ipforward_rt; /* * Ip input routine. Checksum and byte swap header. If fragmented * try to reassemble. Process options. Pass to next level. */ void ipintr() { register struct ip *ip; register struct mbuf *m; register struct ipq *fp; register struct in_ifaddr *ia; struct ipqent *ipqe; int hlen, mff, s; next: /* * Get next datagram off input queue and get IP header * in first mbuf. */ s = splimp(); IF_DEQUEUE(&ipintrq, m); splx(s); if (m == 0) return; #ifdef DIAGNOSTIC if ((m->m_flags & M_PKTHDR) == 0) panic("ipintr no HDR"); #endif /* * If no IP addresses have been set yet but the interfaces * are receiving, can't do anything with incoming packets yet. */ if (in_ifaddr.tqh_first == 0) goto bad; ipstat.ips_total++; if (m->m_len < sizeof (struct ip) && (m = m_pullup(m, sizeof (struct ip))) == 0) { ipstat.ips_toosmall++; goto next; } ip = mtod(m, struct ip *); if (ip->ip_v != IPVERSION) { ipstat.ips_badvers++; goto bad; } hlen = ip->ip_hl << 2; if (hlen < sizeof(struct ip)) { /* minimum header length */ ipstat.ips_badhlen++; goto bad; } if (hlen > m->m_len) { if ((m = m_pullup(m, hlen)) == 0) { ipstat.ips_badhlen++; goto next; } ip = mtod(m, struct ip *); } if ((ip->ip_sum = in_cksum(m, hlen)) != 0) { ipstat.ips_badsum++; goto bad; } /* * Convert fields to host representation. */ NTOHS(ip->ip_len); if (ip->ip_len < hlen) { ipstat.ips_badlen++; goto bad; } NTOHS(ip->ip_id); NTOHS(ip->ip_off); /* * Check that the amount of data in the buffers * is as at least much as the IP header would have us expect. * Trim mbufs if longer than we expect. * Drop packet if shorter than we expect. */ if (m->m_pkthdr.len < ip->ip_len) { ipstat.ips_tooshort++; goto bad; } if (m->m_pkthdr.len > ip->ip_len) { if (m->m_len == m->m_pkthdr.len) { m->m_len = ip->ip_len; m->m_pkthdr.len = ip->ip_len; } else m_adj(m, ip->ip_len - m->m_pkthdr.len); } /* * Process options and, if not destined for us, * ship it on. ip_dooptions returns 1 when an * error was detected (causing an icmp message * to be sent and the original packet to be freed). */ ip_nhops = 0; /* for source routed packets */ if (hlen > sizeof (struct ip) && ip_dooptions(m)) goto next; /* * Check our list of addresses, to see if the packet is for us. */ for (ia = in_ifaddr.tqh_first; ia; ia = ia->ia_list.tqe_next) { if (ip->ip_dst.s_addr == ia->ia_addr.sin_addr.s_addr) goto ours; if (((ip_directedbcast == 0) || (ip_directedbcast && ia->ia_ifp == m->m_pkthdr.rcvif)) && (ia->ia_ifp->if_flags & IFF_BROADCAST)) { if (ip->ip_dst.s_addr == ia->ia_broadaddr.sin_addr.s_addr || ip->ip_dst.s_addr == ia->ia_netbroadcast.s_addr || /* * Look for all-0's host part (old broadcast addr), * either for subnet or net. */ ip->ip_dst.s_addr == ia->ia_subnet || ip->ip_dst.s_addr == ia->ia_net) goto ours; } } if (IN_MULTICAST(ip->ip_dst.s_addr)) { struct in_multi *inm; #ifdef MROUTING extern struct socket *ip_mrouter; if (m->m_flags & M_EXT) { if ((m = m_pullup(m, hlen)) == 0) { ipstat.ips_toosmall++; goto next; } ip = mtod(m, struct ip *); } if (ip_mrouter) { /* * If we are acting as a multicast router, all * incoming multicast packets are passed to the * kernel-level multicast forwarding function. * The packet is returned (relatively) intact; if * ip_mforward() returns a non-zero value, the packet * must be discarded, else it may be accepted below. * * (The IP ident field is put in the same byte order * as expected when ip_mforward() is called from * ip_output().) */ ip->ip_id = htons(ip->ip_id); if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) { ipstat.ips_cantforward++; m_freem(m); goto next; } ip->ip_id = ntohs(ip->ip_id); /* * The process-level routing demon needs to receive * all multicast IGMP packets, whether or not this * host belongs to their destination groups. */ if (ip->ip_p == IPPROTO_IGMP) goto ours; ipstat.ips_forward++; } #endif /* * See if we belong to the destination multicast group on the * arrival interface. */ IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm); if (inm == NULL) { ipstat.ips_cantforward++; m_freem(m); goto next; } goto ours; } if (ip->ip_dst.s_addr == INADDR_BROADCAST || ip->ip_dst.s_addr == INADDR_ANY) goto ours; /* * Not for us; forward if possible and desirable. */ if (ipforwarding == 0) { ipstat.ips_cantforward++; m_freem(m); } else ip_forward(m, 0); goto next; ours: /* * If offset or IP_MF are set, must reassemble. * Otherwise, nothing need be done. * (We could look in the reassembly queue to see * if the packet was previously fragmented, * but it's not worth the time; just let them time out.) */ if (ip->ip_off &~ IP_DF) { if (m->m_flags & M_EXT) { /* XXX */ if ((m = m_pullup(m, sizeof (struct ip))) == 0) { ipstat.ips_toosmall++; goto next; } ip = mtod(m, struct ip *); } /* * Look for queue of fragments * of this datagram. */ for (fp = ipq.lh_first; fp != NULL; fp = fp->ipq_q.le_next) if (ip->ip_id == fp->ipq_id && ip->ip_src.s_addr == fp->ipq_src.s_addr && ip->ip_dst.s_addr == fp->ipq_dst.s_addr && ip->ip_p == fp->ipq_p) goto found; fp = 0; found: /* * Adjust ip_len to not reflect header, * set ipqe_mff if more fragments are expected, * convert offset of this to bytes. */ ip->ip_len -= hlen; mff = (ip->ip_off & IP_MF) != 0; if (mff) { /* * Make sure that fragments have a data length * that's a non-zero multiple of 8 bytes. */ if (ip->ip_len == 0 || (ip->ip_len & 0x7) != 0) { ipstat.ips_badfrags++; goto bad; } } ip->ip_off <<= 3; /* * If datagram marked as having more fragments * or if this is not the first fragment, * attempt reassembly; if it succeeds, proceed. */ if (mff || ip->ip_off) { ipstat.ips_fragments++; MALLOC(ipqe, struct ipqent *, sizeof (struct ipqent), M_IPQ, M_NOWAIT); if (ipqe == NULL) { ipstat.ips_rcvmemdrop++; goto bad; } ipqe->ipqe_mff = mff; ipqe->ipqe_ip = ip; ip = ip_reass(ipqe, fp); if (ip == 0) goto next; ipstat.ips_reassembled++; m = dtom(ip); } else if (fp) ip_freef(fp); } else ip->ip_len -= hlen; /* * Switch out to protocol's input routine. */ ipstat.ips_delivered++; (*inetsw[ip_protox[ip->ip_p]].pr_input)(m, hlen); goto next; bad: m_freem(m); goto next; } /* * Take incoming datagram fragment and try to * reassemble it into whole datagram. If a chain for * reassembly of this datagram already exists, then it * is given as fp; otherwise have to make a chain. */ struct ip * ip_reass(ipqe, fp) register struct ipqent *ipqe; register struct ipq *fp; { register struct mbuf *m = dtom(ipqe->ipqe_ip); register struct ipqent *nq, *p, *q; struct ip *ip; struct mbuf *t; int hlen = ipqe->ipqe_ip->ip_hl << 2; int i, next; /* * Presence of header sizes in mbufs * would confuse code below. */ m->m_data += hlen; m->m_len -= hlen; /* * If first fragment to arrive, create a reassembly queue. */ if (fp == 0) { if ((t = m_get(M_DONTWAIT, MT_FTABLE)) == NULL) goto dropfrag; fp = mtod(t, struct ipq *); LIST_INSERT_HEAD(&ipq, fp, ipq_q); fp->ipq_ttl = IPFRAGTTL; fp->ipq_p = ipqe->ipqe_ip->ip_p; fp->ipq_id = ipqe->ipqe_ip->ip_id; LIST_INIT(&fp->ipq_fragq); fp->ipq_src = ipqe->ipqe_ip->ip_src; fp->ipq_dst = ipqe->ipqe_ip->ip_dst; p = NULL; goto insert; } /* * Find a segment which begins after this one does. */ for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL; p = q, q = q->ipqe_q.le_next) if (q->ipqe_ip->ip_off > ipqe->ipqe_ip->ip_off) break; /* * If there is a preceding segment, it may provide some of * our data already. If so, drop the data from the incoming * segment. If it provides all of our data, drop us. */ if (p != NULL) { i = p->ipqe_ip->ip_off + p->ipqe_ip->ip_len - ipqe->ipqe_ip->ip_off; if (i > 0) { if (i >= ipqe->ipqe_ip->ip_len) goto dropfrag; m_adj(dtom(ipqe->ipqe_ip), i); ipqe->ipqe_ip->ip_off += i; ipqe->ipqe_ip->ip_len -= i; } } /* * While we overlap succeeding segments trim them or, * if they are completely covered, dequeue them. */ for (; q != NULL && ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len > q->ipqe_ip->ip_off; q = nq) { i = (ipqe->ipqe_ip->ip_off + ipqe->ipqe_ip->ip_len) - q->ipqe_ip->ip_off; if (i < q->ipqe_ip->ip_len) { q->ipqe_ip->ip_len -= i; q->ipqe_ip->ip_off += i; m_adj(dtom(q->ipqe_ip), i); break; } nq = q->ipqe_q.le_next; m_freem(dtom(q->ipqe_ip)); LIST_REMOVE(q, ipqe_q); FREE(q, M_IPQ); } insert: /* * Stick new segment in its place; * check for complete reassembly. */ if (p == NULL) { LIST_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q); } else { LIST_INSERT_AFTER(p, ipqe, ipqe_q); } next = 0; for (p = NULL, q = fp->ipq_fragq.lh_first; q != NULL; p = q, q = q->ipqe_q.le_next) { if (q->ipqe_ip->ip_off != next) return (0); next += q->ipqe_ip->ip_len; } if (p->ipqe_mff) return (0); /* * Reassembly is complete; concatenate fragments. */ q = fp->ipq_fragq.lh_first; ip = q->ipqe_ip; m = dtom(q->ipqe_ip); t = m->m_next; m->m_next = 0; m_cat(m, t); nq = q->ipqe_q.le_next; FREE(q, M_IPQ); for (q = nq; q != NULL; q = nq) { t = dtom(q->ipqe_ip); nq = q->ipqe_q.le_next; FREE(q, M_IPQ); m_cat(m, t); } /* * Create header for new ip packet by * modifying header of first packet; * dequeue and discard fragment reassembly header. * Make header visible. */ ip->ip_len = next; ip->ip_src = fp->ipq_src; ip->ip_dst = fp->ipq_dst; LIST_REMOVE(fp, ipq_q); (void) m_free(dtom(fp)); m->m_len += (ip->ip_hl << 2); m->m_data -= (ip->ip_hl << 2); /* some debugging cruft by sklower, below, will go away soon */ if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */ register int plen = 0; for (t = m; m; m = m->m_next) plen += m->m_len; t->m_pkthdr.len = plen; } return (ip); dropfrag: ipstat.ips_fragdropped++; m_freem(m); FREE(ipqe, M_IPQ); return (0); } /* * Free a fragment reassembly header and all * associated datagrams. */ void ip_freef(fp) struct ipq *fp; { register struct ipqent *q, *p; for (q = fp->ipq_fragq.lh_first; q != NULL; q = p) { p = q->ipqe_q.le_next; m_freem(dtom(q->ipqe_ip)); LIST_REMOVE(q, ipqe_q); FREE(q, M_IPQ); } LIST_REMOVE(fp, ipq_q); (void) m_free(dtom(fp)); } /* * IP timer processing; * if a timer expires on a reassembly * queue, discard it. */ void ip_slowtimo() { register struct ipq *fp, *nfp; int s = splsoftnet(); for (fp = ipq.lh_first; fp != NULL; fp = nfp) { nfp = fp->ipq_q.le_next; if (--fp->ipq_ttl == 0) { ipstat.ips_fragtimeout++; ip_freef(fp); } } splx(s); } /* * Drain off all datagram fragments. */ void ip_drain() { while (ipq.lh_first != NULL) { ipstat.ips_fragdropped++; ip_freef(ipq.lh_first); } } /* * Do option processing on a datagram, * possibly discarding it if bad options are encountered, * or forwarding it if source-routed. * Returns 1 if packet has been forwarded/freed, * 0 if the packet should be processed further. */ int ip_dooptions(m) struct mbuf *m; { register struct ip *ip = mtod(m, struct ip *); register u_char *cp; register struct ip_timestamp *ipt; register struct in_ifaddr *ia; int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0; struct in_addr *sin, dst; n_time ntime; dst = ip->ip_dst; cp = (u_char *)(ip + 1); cnt = (ip->ip_hl << 2) - sizeof (struct ip); for (; cnt > 0; cnt -= optlen, cp += optlen) { opt = cp[IPOPT_OPTVAL]; if (opt == IPOPT_EOL) break; if (opt == IPOPT_NOP) optlen = 1; else { optlen = cp[IPOPT_OLEN]; if (optlen <= 0 || optlen > cnt) { code = &cp[IPOPT_OLEN] - (u_char *)ip; goto bad; } } switch (opt) { default: break; /* * Source routing with record. * Find interface with current destination address. * If none on this machine then drop if strictly routed, * or do nothing if loosely routed. * Record interface address and bring up next address * component. If strictly routed make sure next * address is on directly accessible net. */ case IPOPT_LSRR: case IPOPT_SSRR: if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { code = &cp[IPOPT_OFFSET] - (u_char *)ip; goto bad; } ipaddr.sin_addr = ip->ip_dst; ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))); if (ia == 0) { if (opt == IPOPT_SSRR) { type = ICMP_UNREACH; code = ICMP_UNREACH_SRCFAIL; goto bad; } /* * Loose routing, and not at next destination * yet; nothing to do except forward. */ break; } off--; /* 0 origin */ if (off > optlen - sizeof(struct in_addr)) { /* * End of source route. Should be for us. */ save_rte(cp, ip->ip_src); break; } if (!ip_dosourceroute) { char buf[4*sizeof "123"]; strcpy(buf, inet_ntoa(ip->ip_dst)); log(LOG_WARNING, "attempted source route from %s to %s\n", inet_ntoa(ip->ip_src), buf); type = ICMP_UNREACH; code = ICMP_UNREACH_SRCFAIL; goto bad; } /* * locate outgoing interface */ bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr, sizeof(ipaddr.sin_addr)); if (opt == IPOPT_SSRR) { #define INA struct in_ifaddr * #define SA struct sockaddr * if ((ia = (INA)ifa_ifwithdstaddr((SA)&ipaddr)) == 0) ia = (INA)ifa_ifwithnet((SA)&ipaddr); } else ia = ip_rtaddr(ipaddr.sin_addr); if (ia == 0) { type = ICMP_UNREACH; code = ICMP_UNREACH_SRCFAIL; goto bad; } ip->ip_dst = ipaddr.sin_addr; bcopy((caddr_t)&ia->ia_addr.sin_addr, (caddr_t)(cp + off), sizeof(struct in_addr)); cp[IPOPT_OFFSET] += sizeof(struct in_addr); /* * Let ip_intr's mcast routing check handle mcast pkts */ forward = !IN_MULTICAST(ip->ip_dst.s_addr); break; case IPOPT_RR: if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) { code = &cp[IPOPT_OFFSET] - (u_char *)ip; goto bad; } if (!ip_dosourceroute) { char buf[4*sizeof "123"]; strcpy(buf, inet_ntoa(ip->ip_dst)); log(LOG_WARNING, "attempted source route from %s to %s\n", inet_ntoa(ip->ip_src), buf); type = ICMP_UNREACH; code = ICMP_UNREACH_SRCFAIL; goto bad; } /* * If no space remains, ignore. */ off--; /* 0 origin */ if (off > optlen - sizeof(struct in_addr)) break; bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr, sizeof(ipaddr.sin_addr)); /* * locate outgoing interface; if we're the destination, * use the incoming interface (should be same). */ if ((ia = (INA)ifa_ifwithaddr((SA)&ipaddr)) == 0 && (ia = ip_rtaddr(ipaddr.sin_addr)) == 0) { type = ICMP_UNREACH; code = ICMP_UNREACH_HOST; goto bad; } bcopy((caddr_t)&ia->ia_addr.sin_addr, (caddr_t)(cp + off), sizeof(struct in_addr)); cp[IPOPT_OFFSET] += sizeof(struct in_addr); break; case IPOPT_TS: code = cp - (u_char *)ip; ipt = (struct ip_timestamp *)cp; if (ipt->ipt_len < 5) goto bad; if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) { if (++ipt->ipt_oflw == 0) goto bad; break; } sin = (struct in_addr *)(cp + ipt->ipt_ptr - 1); switch (ipt->ipt_flg) { case IPOPT_TS_TSONLY: break; case IPOPT_TS_TSANDADDR: if (ipt->ipt_ptr + sizeof(n_time) + sizeof(struct in_addr) > ipt->ipt_len) goto bad; ipaddr.sin_addr = dst; ia = (INA)ifaof_ifpforaddr((SA)&ipaddr, m->m_pkthdr.rcvif); if (ia == 0) continue; bcopy((caddr_t)&ia->ia_addr.sin_addr, (caddr_t)sin, sizeof(struct in_addr)); ipt->ipt_ptr += sizeof(struct in_addr); break; case IPOPT_TS_PRESPEC: if (ipt->ipt_ptr + sizeof(n_time) + sizeof(struct in_addr) > ipt->ipt_len) goto bad; bcopy((caddr_t)sin, (caddr_t)&ipaddr.sin_addr, sizeof(struct in_addr)); if (ifa_ifwithaddr((SA)&ipaddr) == 0) continue; ipt->ipt_ptr += sizeof(struct in_addr); break; default: goto bad; } ntime = iptime(); bcopy((caddr_t)&ntime, (caddr_t)cp + ipt->ipt_ptr - 1, sizeof(n_time)); ipt->ipt_ptr += sizeof(n_time); } } if (forward) { ip_forward(m, 1); return (1); } return (0); bad: ip->ip_len -= ip->ip_hl << 2; /* XXX icmp_error adds in hdr length */ icmp_error(m, type, code, 0, 0); ipstat.ips_badoptions++; return (1); } /* * Given address of next destination (final or next hop), * return internet address info of interface to be used to get there. */ struct in_ifaddr * ip_rtaddr(dst) struct in_addr dst; { register struct sockaddr_in *sin; sin = satosin(&ipforward_rt.ro_dst); if (ipforward_rt.ro_rt == 0 || dst.s_addr != sin->sin_addr.s_addr) { if (ipforward_rt.ro_rt) { RTFREE(ipforward_rt.ro_rt); ipforward_rt.ro_rt = 0; } sin->sin_family = AF_INET; sin->sin_len = sizeof(*sin); sin->sin_addr = dst; rtalloc(&ipforward_rt); } if (ipforward_rt.ro_rt == 0) return ((struct in_ifaddr *)0); return (ifatoia(ipforward_rt.ro_rt->rt_ifa)); } /* * Save incoming source route for use in replies, * to be picked up later by ip_srcroute if the receiver is interested. */ void save_rte(option, dst) u_char *option; struct in_addr dst; { unsigned olen; olen = option[IPOPT_OLEN]; #ifdef DIAGNOSTIC if (ipprintfs) printf("save_rte: olen %d\n", olen); #endif if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst))) return; bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen); ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr); ip_srcrt.dst = dst; } /* * Retrieve incoming source route for use in replies, * in the same form used by setsockopt. * The first hop is placed before the options, will be removed later. */ struct mbuf * ip_srcroute() { register struct in_addr *p, *q; register struct mbuf *m; if (ip_nhops == 0) return ((struct mbuf *)0); m = m_get(M_DONTWAIT, MT_SOOPTS); if (m == 0) return ((struct mbuf *)0); #define OPTSIZ (sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt)) /* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */ m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) + OPTSIZ; #ifdef DIAGNOSTIC if (ipprintfs) printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len); #endif /* * First save first hop for return route */ p = &ip_srcrt.route[ip_nhops - 1]; *(mtod(m, struct in_addr *)) = *p--; #ifdef DIAGNOSTIC if (ipprintfs) printf(" hops %lx", ntohl(mtod(m, struct in_addr *)->s_addr)); #endif /* * Copy option fields and padding (nop) to mbuf. */ ip_srcrt.nop = IPOPT_NOP; ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF; bcopy((caddr_t)&ip_srcrt.nop, mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ); q = (struct in_addr *)(mtod(m, caddr_t) + sizeof(struct in_addr) + OPTSIZ); #undef OPTSIZ /* * Record return path as an IP source route, * reversing the path (pointers are now aligned). */ while (p >= ip_srcrt.route) { #ifdef DIAGNOSTIC if (ipprintfs) printf(" %lx", ntohl(q->s_addr)); #endif *q++ = *p--; } /* * Last hop goes to final destination. */ *q = ip_srcrt.dst; #ifdef DIAGNOSTIC if (ipprintfs) printf(" %lx\n", ntohl(q->s_addr)); #endif return (m); } /* * Strip out IP options, at higher * level protocol in the kernel. * Second argument is buffer to which options * will be moved, and return value is their length. * XXX should be deleted; last arg currently ignored. */ void ip_stripoptions(m, mopt) register struct mbuf *m; struct mbuf *mopt; { register int i; struct ip *ip = mtod(m, struct ip *); register caddr_t opts; int olen; olen = (ip->ip_hl<<2) - sizeof (struct ip); opts = (caddr_t)(ip + 1); i = m->m_len - (sizeof (struct ip) + olen); bcopy(opts + olen, opts, (unsigned)i); m->m_len -= olen; if (m->m_flags & M_PKTHDR) m->m_pkthdr.len -= olen; ip->ip_hl = sizeof(struct ip) >> 2; } int inetctlerrmap[PRC_NCMDS] = { 0, 0, 0, 0, 0, EMSGSIZE, EHOSTDOWN, EHOSTUNREACH, EHOSTUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED, EMSGSIZE, EHOSTUNREACH, 0, 0, 0, 0, 0, 0, ENOPROTOOPT }; /* * Forward a packet. If some error occurs return the sender * an icmp packet. Note we can't always generate a meaningful * icmp message because icmp doesn't have a large enough repertoire * of codes and types. * * If not forwarding, just drop the packet. This could be confusing * if ipforwarding was zero but some routing protocol was advancing * us as a gateway to somewhere. However, we must let the routing * protocol deal with that. * * The srcrt parameter indicates whether the packet is being forwarded * via a source route. */ void ip_forward(m, srcrt) struct mbuf *m; int srcrt; { register struct ip *ip = mtod(m, struct ip *); register struct sockaddr_in *sin; register struct rtentry *rt; int error, type = 0, code = 0; struct mbuf *mcopy; n_long dest; struct ifnet *destifp; dest = 0; #ifdef DIAGNOSTIC if (ipprintfs) printf("forward: src %lx dst %x ttl %x\n", ip->ip_src.s_addr, ip->ip_dst.s_addr, ip->ip_ttl); #endif if (m->m_flags & M_BCAST || in_canforward(ip->ip_dst) == 0) { ipstat.ips_cantforward++; m_freem(m); return; } HTONS(ip->ip_id); if (ip->ip_ttl <= IPTTLDEC) { icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0); return; } ip->ip_ttl -= IPTTLDEC; sin = satosin(&ipforward_rt.ro_dst); if ((rt = ipforward_rt.ro_rt) == 0 || ip->ip_dst.s_addr != sin->sin_addr.s_addr) { if (ipforward_rt.ro_rt) { RTFREE(ipforward_rt.ro_rt); ipforward_rt.ro_rt = 0; } sin->sin_family = AF_INET; sin->sin_len = sizeof(*sin); sin->sin_addr = ip->ip_dst; rtalloc(&ipforward_rt); if (ipforward_rt.ro_rt == 0) { icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0); return; } rt = ipforward_rt.ro_rt; } /* * Save at most 64 bytes of the packet in case * we need to generate an ICMP message to the src. */ mcopy = m_copy(m, 0, imin((int)ip->ip_len, 64)); /* * If forwarding packet using same interface that it came in on, * perhaps should send a redirect to sender to shortcut a hop. * Only send redirect if source is sending directly to us, * and if packet was not source routed (or has any options). * Also, don't send redirect if forwarding using a default route * or a route modified by a redirect. */ if (rt->rt_ifp == m->m_pkthdr.rcvif && (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 && satosin(rt_key(rt))->sin_addr.s_addr != 0 && ipsendredirects && !srcrt) { if (rt->rt_ifa && (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) == ifatoia(rt->rt_ifa)->ia_subnet) { if (rt->rt_flags & RTF_GATEWAY) dest = satosin(rt->rt_gateway)->sin_addr.s_addr; else dest = ip->ip_dst.s_addr; /* Router requirements says to only send host redirects */ type = ICMP_REDIRECT; code = ICMP_REDIRECT_HOST; #ifdef DIAGNOSTIC if (ipprintfs) printf("redirect (%d) to %lx\n", code, (u_int32_t)dest); #endif } } error = ip_output(m, (struct mbuf *)0, &ipforward_rt, (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 0); if (error) ipstat.ips_cantforward++; else { ipstat.ips_forward++; if (type) ipstat.ips_redirectsent++; else { if (mcopy) m_freem(mcopy); return; } } if (mcopy == NULL) return; destifp = NULL; switch (error) { case 0: /* forwarded, but need redirect */ /* type, code set above */ break; case ENETUNREACH: /* shouldn't happen, checked above */ case EHOSTUNREACH: case ENETDOWN: case EHOSTDOWN: default: type = ICMP_UNREACH; code = ICMP_UNREACH_HOST; break; case EMSGSIZE: type = ICMP_UNREACH; code = ICMP_UNREACH_NEEDFRAG; if (ipforward_rt.ro_rt) destifp = ipforward_rt.ro_rt->rt_ifp; ipstat.ips_cantfrag++; break; case ENOBUFS: type = ICMP_SOURCEQUENCH; code = 0; break; } icmp_error(mcopy, type, code, dest, destifp); } int ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen) int *name; u_int namelen; void *oldp; size_t *oldlenp; void *newp; size_t newlen; { /* All sysctl names at this level are terminal. */ if (namelen != 1) return (ENOTDIR); switch (name[0]) { case IPCTL_FORWARDING: return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding)); case IPCTL_SENDREDIRECTS: return (sysctl_int(oldp, oldlenp, newp, newlen, &ipsendredirects)); case IPCTL_DEFTTL: return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl)); #ifdef notyet case IPCTL_DEFMTU: return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu)); #endif case IPCTL_SOURCEROUTE: /* * Don't allow this to change in a secure environment. */ if (securelevel > 0) return (EPERM); return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_dosourceroute)); case IPCTL_DIRECTEDBCAST: return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_directedbcast)); default: return (EOPNOTSUPP); } /* NOTREACHED */ }