/* $NetBSD: ip_icmp.c,v 1.178 2022/08/29 09:14:02 knakahara Exp $ */ /* * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Public Access Networks Corporation ("Panix"). It was developed under * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon. * * This code is derived from software contributed to The NetBSD Foundation * by Jason R. Thorpe of Zembu Labs, Inc. * * 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. * * 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) 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) 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. 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_icmp.c 8.2 (Berkeley) 1/4/94 */ #include __KERNEL_RCSID(0, "$NetBSD: ip_icmp.c,v 1.178 2022/08/29 09:14:02 knakahara Exp $"); #ifdef _KERNEL_OPT #include "opt_ipsec.h" #endif #include #include #include #include #include #include /* For softnet_lock */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef IPSEC #include #include #endif /* * ICMP routines: error generation, receive packet processing, and * routines to turnaround packets back to the originator, and * host table maintenance routines. */ int icmpmaskrepl = 0; int icmpbmcastecho = 0; int icmpreturndatabytes = 8; percpu_t *icmpstat_percpu; /* * List of callbacks to notify when Path MTU changes are made. */ struct icmp_mtudisc_callback { LIST_ENTRY(icmp_mtudisc_callback) mc_list; void (*mc_func)(struct in_addr); }; LIST_HEAD(, icmp_mtudisc_callback) icmp_mtudisc_callbacks = LIST_HEAD_INITIALIZER(&icmp_mtudisc_callbacks); /* unused... */ u_int ip_next_mtu(u_int, int); bool icmp_dynamic_rt_msg = false; static int icmperrppslim = 100; /* 100pps */ static int icmperrpps_count = 0; static struct timeval icmperrppslim_last; static int icmp_rediraccept = 1; static int icmp_redirtimeout = 600; static struct rttimer_queue *icmp_redirect_timeout_q = NULL; /* Protect mtudisc and redirect stuff */ static kmutex_t icmp_mtx __cacheline_aligned; static void icmp_send(struct mbuf *, struct mbuf *); static void icmp_mtudisc_timeout(struct rtentry *, struct rttimer *); static void icmp_redirect_timeout(struct rtentry *, struct rttimer *); static void sysctl_netinet_icmp_setup(struct sysctllog **); /* workqueue-based pr_input */ static struct wqinput *icmp_wqinput; static void _icmp_input(struct mbuf *, int, int); void icmp_init(void) { sysctl_netinet_icmp_setup(NULL); mutex_init(&icmp_mtx, MUTEX_DEFAULT, IPL_NONE); /* * This is only useful if the user initializes redirtimeout to * something other than zero. */ mutex_enter(&icmp_mtx); icmp_redirect_timeout_q = rt_timer_queue_create(icmp_redirtimeout); mutex_exit(&icmp_mtx); icmpstat_percpu = percpu_alloc(sizeof(uint64_t) * ICMP_NSTATS); icmp_wqinput = wqinput_create("icmp", _icmp_input); } void icmp_mtudisc_lock(void) { mutex_enter(&icmp_mtx); } void icmp_mtudisc_unlock(void) { mutex_exit(&icmp_mtx); } /* * Register a Path MTU Discovery callback. */ void icmp_mtudisc_callback_register(void (*func)(struct in_addr)) { struct icmp_mtudisc_callback *mc, *new; new = kmem_alloc(sizeof(*mc), KM_SLEEP); mutex_enter(&icmp_mtx); for (mc = LIST_FIRST(&icmp_mtudisc_callbacks); mc != NULL; mc = LIST_NEXT(mc, mc_list)) { if (mc->mc_func == func) { mutex_exit(&icmp_mtx); kmem_free(new, sizeof(*mc)); return; } } new->mc_func = func; LIST_INSERT_HEAD(&icmp_mtudisc_callbacks, new, mc_list); mutex_exit(&icmp_mtx); } /* * Generate an error packet of type error in response to a bad IP packet. 'n' * contains this packet. We create 'm' and send it. * * As we are not required to return everything we have, we return whatever * we can return at ease. * * Note that ICMP datagrams longer than 576 octets are out of spec according * to RFC1812; the limit on icmpreturndatabytes will keep things below that * limit. */ void icmp_error(struct mbuf *n, int type, int code, n_long dest, int destmtu) { struct ip *oip = mtod(n, struct ip *), *nip; const unsigned oiphlen = oip->ip_hl << 2; struct icmp *icp; struct mbuf *m; struct m_tag *mtag; unsigned datalen, mblen; int totlen; if (type != ICMP_REDIRECT) ICMP_STATINC(ICMP_STAT_ERROR); /* * Don't send error if: * - The original packet was encrypted. * - The packet is multicast or broadcast. * - The packet is not the first fragment of the message. * - The packet is an ICMP message with an unknown type. */ if (n->m_flags & M_DECRYPTED) goto freeit; if (n->m_flags & (M_BCAST|M_MCAST)) goto freeit; if (oip->ip_off &~ htons(IP_MF|IP_DF)) goto freeit; if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT && n->m_len >= oiphlen + ICMP_MINLEN) { struct icmp *oicp = (struct icmp *)((char *)oip + oiphlen); if (!ICMP_INFOTYPE(oicp->icmp_type)) { ICMP_STATINC(ICMP_STAT_OLDICMP); goto freeit; } } /* * First, do a rate limitation check. */ if (icmp_ratelimit(&oip->ip_src, type, code)) { /* XXX stat */ goto freeit; } /* * Compute the number of bytes we will put in 'icmp_ip'. Truncate * it to the size of the mbuf, if it's too big. */ datalen = oiphlen + uimin(icmpreturndatabytes, ntohs(oip->ip_len) - oiphlen); mblen = 0; for (m = n; m && (mblen < datalen); m = m->m_next) mblen += m->m_len; datalen = uimin(mblen, datalen); /* * Compute the total length of the new packet. Truncate it if it's * bigger than the size of a cluster. */ CTASSERT(ICMP_MINLEN + sizeof(struct ip) <= MCLBYTES); totlen = sizeof(struct ip) + ICMP_MINLEN + datalen; if (totlen > MCLBYTES) { datalen = MCLBYTES - ICMP_MINLEN - sizeof(struct ip); totlen = MCLBYTES; } /* * Allocate the mbuf for the new packet. */ m = m_gethdr(M_DONTWAIT, MT_HEADER); if (m && (totlen > MHLEN)) { MCLGET(m, M_DONTWAIT); if ((m->m_flags & M_EXT) == 0) { m_freem(m); m = NULL; } } if (m == NULL) goto freeit; MCLAIM(m, n->m_owner); m->m_len = totlen; m->m_pkthdr.len = m->m_len; m_copy_rcvif(m, n); if ((u_int)type > ICMP_MAXTYPE) panic("icmp_error"); ICMP_STATINC(ICMP_STAT_OUTHIST + type); if ((m->m_flags & M_EXT) == 0) m_align(m, m->m_len); /* * Get pointers on the IP header and the ICMP header. */ nip = mtod(m, struct ip *); icp = (struct icmp *)(nip + 1); /* * Fill in the fields of the ICMP header: icmp_type, icmp_code * and icmp_ip. icmp_cksum gets filled later. */ icp->icmp_type = type; if (type == ICMP_REDIRECT) { icp->icmp_gwaddr.s_addr = dest; } else { icp->icmp_void = 0; /* * The following assignments assume an overlay with the * zeroed icmp_void field. */ if (type == ICMP_PARAMPROB) { icp->icmp_pptr = code; code = 0; } else if (type == ICMP_UNREACH && code == ICMP_UNREACH_NEEDFRAG && destmtu) icp->icmp_nextmtu = htons(destmtu); } icp->icmp_code = code; m_copydata(n, 0, datalen, (void *)&icp->icmp_ip); /* * Now, copy the old IP header (without options) in front of the * ICMP message. The src/dst fields will be swapped in icmp_reflect. */ /* ip_v set in ip_output */ nip->ip_hl = sizeof(struct ip) >> 2; nip->ip_tos = 0; nip->ip_len = htons(m->m_len); /* ip_id set in ip_output */ nip->ip_off = htons(0); /* ip_ttl set in icmp_reflect */ nip->ip_p = IPPROTO_ICMP; nip->ip_src = oip->ip_src; nip->ip_dst = oip->ip_dst; /* move PF m_tag to new packet, if it exists */ mtag = m_tag_find(n, PACKET_TAG_PF); if (mtag != NULL) { m_tag_unlink(n, mtag); m_tag_prepend(m, mtag); } icmp_reflect(m); freeit: m_freem(n); } struct sockaddr_in icmpsrc = { .sin_len = sizeof(struct sockaddr_in), .sin_family = AF_INET, }; /* * Process a received ICMP message. */ static void _icmp_input(struct mbuf *m, int hlen, int proto) { struct icmp *icp; struct ip *ip = mtod(m, struct ip *); int icmplen; int i; struct in_ifaddr *ia; void *(*ctlfunc)(int, const struct sockaddr *, void *); int code; struct rtentry *rt; struct sockaddr_in icmpdst = { .sin_len = sizeof(struct sockaddr_in), .sin_family = AF_INET, }; struct sockaddr_in icmpgw = { .sin_len = sizeof(struct sockaddr_in), .sin_family = AF_INET, }; /* * Locate icmp structure in mbuf, and check * that not corrupted and of at least minimum length. */ icmplen = ntohs(ip->ip_len) - hlen; if (icmplen < ICMP_MINLEN) { ICMP_STATINC(ICMP_STAT_TOOSHORT); goto freeit; } i = hlen + uimin(icmplen, ICMP_ADVLENMIN); if (M_UNWRITABLE(m, i) && (m = m_pullup(m, i)) == NULL) { ICMP_STATINC(ICMP_STAT_TOOSHORT); return; } ip = mtod(m, struct ip *); m->m_len -= hlen; m->m_data += hlen; icp = mtod(m, struct icmp *); /* Don't need to assert alignment, here. */ if (in_cksum(m, icmplen)) { ICMP_STATINC(ICMP_STAT_CHECKSUM); goto freeit; } m->m_len += hlen; m->m_data -= hlen; if (icp->icmp_type > ICMP_MAXTYPE) goto raw; ICMP_STATINC(ICMP_STAT_INHIST + icp->icmp_type); code = icp->icmp_code; switch (icp->icmp_type) { case ICMP_UNREACH: switch (code) { case ICMP_UNREACH_PROTOCOL: code = PRC_UNREACH_PROTOCOL; break; case ICMP_UNREACH_PORT: code = PRC_UNREACH_PORT; break; case ICMP_UNREACH_SRCFAIL: code = PRC_UNREACH_SRCFAIL; break; case ICMP_UNREACH_NEEDFRAG: code = PRC_MSGSIZE; break; case ICMP_UNREACH_NET: case ICMP_UNREACH_NET_UNKNOWN: case ICMP_UNREACH_NET_PROHIB: case ICMP_UNREACH_TOSNET: code = PRC_UNREACH_NET; break; case ICMP_UNREACH_HOST: case ICMP_UNREACH_HOST_UNKNOWN: case ICMP_UNREACH_ISOLATED: case ICMP_UNREACH_HOST_PROHIB: case ICMP_UNREACH_TOSHOST: case ICMP_UNREACH_ADMIN_PROHIBIT: case ICMP_UNREACH_HOST_PREC: case ICMP_UNREACH_PREC_CUTOFF: code = PRC_UNREACH_HOST; break; default: goto badcode; } goto deliver; case ICMP_TIMXCEED: if (code > 1) goto badcode; code += PRC_TIMXCEED_INTRANS; goto deliver; case ICMP_PARAMPROB: if (code > 1) goto badcode; code = PRC_PARAMPROB; goto deliver; case ICMP_SOURCEQUENCH: if (code) goto badcode; code = PRC_QUENCH; goto deliver; deliver: /* * Problem with datagram; advise higher level routines. */ if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { ICMP_STATINC(ICMP_STAT_BADLEN); goto freeit; } if (m->m_len < hlen + ICMP_ADVLEN(icp)) { m = m_pullup(m, hlen + ICMP_ADVLEN(icp)); if (m == NULL) goto freeit; } ip = mtod(m, struct ip *); icp = (struct icmp *)(mtod(m, uint8_t *) + hlen); if (IN_MULTICAST(icp->icmp_ip.ip_dst.s_addr)) goto badcode; icmpsrc.sin_addr = icp->icmp_ip.ip_dst; ctlfunc = inetsw[ip_protox[icp->icmp_ip.ip_p]].pr_ctlinput; if (ctlfunc) (void) (*ctlfunc)(code, sintosa(&icmpsrc), &icp->icmp_ip); break; badcode: ICMP_STATINC(ICMP_STAT_BADCODE); break; case ICMP_ECHO: if (!icmpbmcastecho && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { ICMP_STATINC(ICMP_STAT_BMCASTECHO); break; } icp->icmp_type = ICMP_ECHOREPLY; goto reflect; case ICMP_TSTAMP: if (icmplen < ICMP_TSLEN) { ICMP_STATINC(ICMP_STAT_BADLEN); break; } if (!icmpbmcastecho && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { ICMP_STATINC(ICMP_STAT_BMCASTTSTAMP); break; } icp->icmp_type = ICMP_TSTAMPREPLY; icp->icmp_rtime = iptime(); icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ goto reflect; case ICMP_MASKREQ: { struct ifnet *rcvif; int s, ss; struct ifaddr *ifa = NULL; if (icmpmaskrepl == 0) break; /* * We are not able to respond with all ones broadcast * unless we receive it over a point-to-point interface. */ if (icmplen < ICMP_MASKLEN) { ICMP_STATINC(ICMP_STAT_BADLEN); break; } if (ip->ip_dst.s_addr == INADDR_BROADCAST || in_nullhost(ip->ip_dst)) icmpdst.sin_addr = ip->ip_src; else icmpdst.sin_addr = ip->ip_dst; ss = pserialize_read_enter(); rcvif = m_get_rcvif(m, &s); if (__predict_true(rcvif != NULL)) ifa = ifaof_ifpforaddr(sintosa(&icmpdst), rcvif); m_put_rcvif(rcvif, &s); if (ifa == NULL) { pserialize_read_exit(ss); break; } ia = ifatoia(ifa); icp->icmp_type = ICMP_MASKREPLY; icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; if (in_nullhost(ip->ip_src)) { if (ia->ia_ifp->if_flags & IFF_BROADCAST) ip->ip_src = ia->ia_broadaddr.sin_addr; else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) ip->ip_src = ia->ia_dstaddr.sin_addr; } pserialize_read_exit(ss); reflect: { uint64_t *icps = percpu_getref(icmpstat_percpu); icps[ICMP_STAT_REFLECT]++; icps[ICMP_STAT_OUTHIST + icp->icmp_type]++; percpu_putref(icmpstat_percpu); } icmp_reflect(m); return; } case ICMP_REDIRECT: if (code > 3) goto badcode; if (icmp_rediraccept == 0) goto freeit; if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || icp->icmp_ip.ip_hl < (sizeof(struct ip) >> 2)) { ICMP_STATINC(ICMP_STAT_BADLEN); break; } /* * Short circuit routing redirects to force * immediate change in the kernel's routing * tables. The message is also handed to anyone * listening on a raw socket (e.g. the routing * daemon for use in updating its tables). */ icmpgw.sin_addr = ip->ip_src; icmpdst.sin_addr = icp->icmp_gwaddr; icmpsrc.sin_addr = icp->icmp_ip.ip_dst; rt = NULL; rtredirect(sintosa(&icmpsrc), sintosa(&icmpdst), NULL, RTF_GATEWAY | RTF_HOST, sintosa(&icmpgw), &rt); mutex_enter(&icmp_mtx); if (rt != NULL && icmp_redirtimeout != 0) { i = rt_timer_add(rt, icmp_redirect_timeout, icmp_redirect_timeout_q); if (i) { char buf[INET_ADDRSTRLEN]; log(LOG_ERR, "ICMP: redirect failed to " "register timeout for route to %s, " "code %d\n", IN_PRINT(buf, &icp->icmp_ip.ip_dst), i); } } mutex_exit(&icmp_mtx); if (rt != NULL) rt_unref(rt); pfctlinput(PRC_REDIRECT_HOST, sintosa(&icmpsrc)); #if defined(IPSEC) if (ipsec_used) key_sa_routechange((struct sockaddr *)&icmpsrc); #endif break; /* * No kernel processing for the following; * just fall through to send to raw listener. */ case ICMP_ECHOREPLY: case ICMP_ROUTERADVERT: case ICMP_ROUTERSOLICIT: case ICMP_TSTAMPREPLY: case ICMP_IREQREPLY: case ICMP_MASKREPLY: default: break; } raw: /* * Currently, pim_input() is always called holding softnet_lock * by ipintr()(!NET_MPSAFE) or PR_INPUT_WRAP()(NET_MPSAFE). */ KASSERT(mutex_owned(softnet_lock)); rip_input(m, hlen, proto); return; freeit: m_freem(m); return; } void icmp_input(struct mbuf *m, int off, int proto) { wqinput_input(icmp_wqinput, m, off, proto); } /* * Reflect the ip packet back to the source */ void icmp_reflect(struct mbuf *m) { struct ip *ip = mtod(m, struct ip *); struct in_ifaddr *ia; struct ifaddr *ifa; struct sockaddr_in *sin; struct in_addr t; struct mbuf *opts = NULL; int optlen = (ip->ip_hl << 2) - sizeof(struct ip); struct ifnet *rcvif; struct psref psref, psref_ia; int s; int bound; bound = curlwp_bind(); if (!in_canforward(ip->ip_src) && ((ip->ip_src.s_addr & IN_CLASSA_NET) != htonl(IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) { m_freem(m); /* Bad return address */ goto done; /* ip_output() will check for broadcast */ } t = ip->ip_dst; ip->ip_dst = ip->ip_src; /* * If the incoming packet was addressed directly to us, use * dst as the src for the reply. Otherwise (broadcast or * anonymous), use an address which corresponds to the * incoming interface, with a preference for the address which * corresponds to the route to the destination of the ICMP. */ /* Look for packet addressed to us */ ia = in_get_ia_psref(t, &psref_ia); if (ia && (ia->ia4_flags & IN_IFF_NOTREADY)) { ia4_release(ia, &psref_ia); ia = NULL; } rcvif = m_get_rcvif_psref(m, &psref); /* look for packet sent to broadcast address */ if (ia == NULL && rcvif && (rcvif->if_flags & IFF_BROADCAST)) { s = pserialize_read_enter(); IFADDR_READER_FOREACH(ifa, rcvif) { if (ifa->ifa_addr->sa_family != AF_INET) continue; if (in_hosteq(t,ifatoia(ifa)->ia_broadaddr.sin_addr)) { ia = ifatoia(ifa); if ((ia->ia4_flags & IN_IFF_NOTREADY) == 0) break; ia = NULL; } } if (ia != NULL) ia4_acquire(ia, &psref_ia); pserialize_read_exit(s); } sin = ia ? &ia->ia_addr : NULL; /* * if the packet is addressed somewhere else, compute the * source address for packets routed back to the source, and * use that, if it's an address on the interface which * received the packet */ if (sin == NULL && rcvif) { struct sockaddr_in sin_dst; struct route icmproute; int errornum; sockaddr_in_init(&sin_dst, &ip->ip_dst, 0); memset(&icmproute, 0, sizeof(icmproute)); errornum = 0; ia = in_selectsrc(&sin_dst, &icmproute, 0, NULL, &errornum, &psref_ia); /* errornum is never used */ rtcache_free(&icmproute); /* check to make sure sin is a source address on rcvif */ if (ia != NULL) { sin = &ia->ia_addr; t = sin->sin_addr; sin = NULL; ia4_release(ia, &psref_ia); ia = in_get_ia_on_iface_psref(t, rcvif, &psref_ia); if (ia != NULL) sin = &ia->ia_addr; } } /* * if it was not addressed to us, but the route doesn't go out * the source interface, pick an address on the source * interface. This can happen when routing is asymmetric, or * when the incoming packet was encapsulated */ if (sin == NULL && rcvif) { KASSERT(ia == NULL); s = pserialize_read_enter(); IFADDR_READER_FOREACH(ifa, rcvif) { if (ifa->ifa_addr->sa_family != AF_INET) continue; sin = &(ifatoia(ifa)->ia_addr); ia = ifatoia(ifa); ia4_acquire(ia, &psref_ia); break; } pserialize_read_exit(s); } m_put_rcvif_psref(rcvif, &psref); /* * The following happens if the packet was not addressed to us, * and was received on an interface with no IP address: * We find the first AF_INET address on the first non-loopback * interface. */ if (sin == NULL) { KASSERT(ia == NULL); s = pserialize_read_enter(); IN_ADDRLIST_READER_FOREACH(ia) { if (ia->ia_ifp->if_flags & IFF_LOOPBACK) continue; sin = &ia->ia_addr; ia4_acquire(ia, &psref_ia); break; } pserialize_read_exit(s); } /* * If we still didn't find an address, punt. We could have an * interface up (and receiving packets) with no address. */ if (sin == NULL) { KASSERT(ia == NULL); m_freem(m); goto done; } ip->ip_src = sin->sin_addr; ip->ip_ttl = MAXTTL; if (ia != NULL) ia4_release(ia, &psref_ia); if (optlen > 0) { u_char *cp; int opt, cnt; u_int len; /* * Retrieve any source routing from the incoming packet; * add on any record-route or timestamp options. */ cp = (u_char *)(ip + 1); if ((opts = ip_srcroute(m)) == NULL && (opts = m_gethdr(M_DONTWAIT, MT_HEADER))) { MCLAIM(opts, m->m_owner); opts->m_len = sizeof(struct in_addr); *mtod(opts, struct in_addr *) = zeroin_addr; } if (opts) { for (cnt = optlen; cnt > 0; cnt -= len, cp += len) { opt = cp[IPOPT_OPTVAL]; if (opt == IPOPT_EOL) break; if (opt == IPOPT_NOP) len = 1; else { if (cnt < IPOPT_OLEN + sizeof(*cp)) break; len = cp[IPOPT_OLEN]; if (len < IPOPT_OLEN + sizeof(*cp) || len > cnt) break; } /* Overflows can't happen */ KASSERT(opts->m_len + len <= MHLEN); if (opt == IPOPT_RR || opt == IPOPT_TS || opt == IPOPT_SECURITY) { memmove(mtod(opts, char *) + opts->m_len, cp, len); opts->m_len += len; } } /* Terminate & pad, if necessary */ if ((cnt = opts->m_len % 4) != 0) { for (; cnt < 4; cnt++) { *(mtod(opts, char *) + opts->m_len) = IPOPT_EOL; opts->m_len++; } } } /* * Now strip out original options by copying rest of first * mbuf's data back, and adjust the IP length. */ ip->ip_len = htons(ntohs(ip->ip_len) - optlen); ip->ip_hl = sizeof(struct ip) >> 2; m->m_len -= optlen; if (m->m_flags & M_PKTHDR) m->m_pkthdr.len -= optlen; optlen += sizeof(struct ip); memmove(ip + 1, (char *)ip + optlen, (unsigned)(m->m_len - sizeof(struct ip))); } m_tag_delete_chain(m); m->m_flags &= ~(M_BCAST|M_MCAST); /* * Clear any in-bound checksum flags for this packet. */ if (m->m_flags & M_PKTHDR) m->m_pkthdr.csum_flags = 0; icmp_send(m, opts); done: curlwp_bindx(bound); if (opts) (void)m_free(opts); } /* * Send an icmp packet back to the ip level, * after supplying a checksum. */ static void icmp_send(struct mbuf *m, struct mbuf *opts) { struct ip *ip = mtod(m, struct ip *); int hlen; struct icmp *icp; hlen = ip->ip_hl << 2; m->m_data += hlen; m->m_len -= hlen; icp = mtod(m, struct icmp *); icp->icmp_cksum = 0; icp->icmp_cksum = in_cksum(m, ntohs(ip->ip_len) - hlen); m->m_data -= hlen; m->m_len += hlen; (void)ip_output(m, opts, NULL, 0, NULL, NULL); } n_time iptime(void) { struct timeval atv; u_long t; microtime(&atv); t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; return (htonl(t)); } /* * sysctl helper routine for net.inet.icmp.returndatabytes. ensures * that the new value is in the correct range. */ static int sysctl_net_inet_icmp_returndatabytes(SYSCTLFN_ARGS) { int error, t; struct sysctlnode node; node = *rnode; node.sysctl_data = &t; t = icmpreturndatabytes; error = sysctl_lookup(SYSCTLFN_CALL(&node)); if (error || newp == NULL) return error; if (t < 8 || t > 512) return EINVAL; icmpreturndatabytes = t; return 0; } /* * sysctl helper routine for net.inet.icmp.redirtimeout. ensures that * the given value is not less than zero and then resets the timeout * queue. */ static int sysctl_net_inet_icmp_redirtimeout(SYSCTLFN_ARGS) { int error, tmp; struct sysctlnode node; mutex_enter(&icmp_mtx); node = *rnode; node.sysctl_data = &tmp; tmp = icmp_redirtimeout; error = sysctl_lookup(SYSCTLFN_CALL(&node)); if (error || newp == NULL) goto out; if (tmp < 0) { error = EINVAL; goto out; } icmp_redirtimeout = tmp; /* * was it a *defined* side-effect that anyone even *reading* * this value causes these things to happen? */ if (icmp_redirect_timeout_q != NULL) { if (icmp_redirtimeout == 0) { rt_timer_queue_destroy(icmp_redirect_timeout_q); icmp_redirect_timeout_q = NULL; } else { rt_timer_queue_change(icmp_redirect_timeout_q, icmp_redirtimeout); } } else if (icmp_redirtimeout > 0) { icmp_redirect_timeout_q = rt_timer_queue_create(icmp_redirtimeout); } error = 0; out: mutex_exit(&icmp_mtx); return error; } static int sysctl_net_inet_icmp_stats(SYSCTLFN_ARGS) { return (NETSTAT_SYSCTL(icmpstat_percpu, ICMP_NSTATS)); } static void sysctl_netinet_icmp_setup(struct sysctllog **clog) { sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_NODE, "inet", NULL, NULL, 0, NULL, 0, CTL_NET, PF_INET, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_NODE, "icmp", SYSCTL_DESCR("ICMPv4 related settings"), NULL, 0, NULL, 0, CTL_NET, PF_INET, IPPROTO_ICMP, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "maskrepl", SYSCTL_DESCR("Respond to ICMP_MASKREQ messages"), NULL, 0, &icmpmaskrepl, 0, CTL_NET, PF_INET, IPPROTO_ICMP, ICMPCTL_MASKREPL, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "returndatabytes", SYSCTL_DESCR("Number of bytes to return in an ICMP " "error message"), sysctl_net_inet_icmp_returndatabytes, 0, &icmpreturndatabytes, 0, CTL_NET, PF_INET, IPPROTO_ICMP, ICMPCTL_RETURNDATABYTES, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "errppslimit", SYSCTL_DESCR("Maximum number of outgoing ICMP error " "messages per second"), NULL, 0, &icmperrppslim, 0, CTL_NET, PF_INET, IPPROTO_ICMP, ICMPCTL_ERRPPSLIMIT, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "rediraccept", SYSCTL_DESCR("Accept ICMP_REDIRECT messages"), NULL, 0, &icmp_rediraccept, 0, CTL_NET, PF_INET, IPPROTO_ICMP, ICMPCTL_REDIRACCEPT, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "redirtimeout", SYSCTL_DESCR("Lifetime of ICMP_REDIRECT generated " "routes"), sysctl_net_inet_icmp_redirtimeout, 0, &icmp_redirtimeout, 0, CTL_NET, PF_INET, IPPROTO_ICMP, ICMPCTL_REDIRTIMEOUT, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT, CTLTYPE_STRUCT, "stats", SYSCTL_DESCR("ICMP statistics"), sysctl_net_inet_icmp_stats, 0, NULL, 0, CTL_NET, PF_INET, IPPROTO_ICMP, ICMPCTL_STATS, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "bmcastecho", SYSCTL_DESCR("Respond to ICMP_ECHO or ICMP_TIMESTAMP " "message to the broadcast or multicast"), NULL, 0, &icmpbmcastecho, 0, CTL_NET, PF_INET, IPPROTO_ICMP, ICMPCTL_BMCASTECHO, CTL_EOL); sysctl_createv(clog, 0, NULL, NULL, CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_BOOL, "dynamic_rt_msg", SYSCTL_DESCR("Send routing message for RTF_DYNAMIC"), NULL, 0, &icmp_dynamic_rt_msg, 0, CTL_NET, PF_INET, IPPROTO_ICMP, ICMPCTL_DYNAMIC_RT_MSG, CTL_EOL); } void icmp_statinc(u_int stat) { KASSERT(stat < ICMP_NSTATS); ICMP_STATINC(stat); } /* Table of common MTUs */ static const u_int mtu_table[] = { 65535, 65280, 32000, 17914, 9180, 8166, 4352, 2002, 1492, 1006, 508, 296, 68, 0 }; void icmp_mtudisc(struct icmp *icp, struct in_addr faddr) { struct icmp_mtudisc_callback *mc; struct sockaddr *dst = sintosa(&icmpsrc); struct rtentry *rt; u_long mtu = ntohs(icp->icmp_nextmtu); /* Why a long? IPv6 */ int error; rt = rtalloc1(dst, 1); if (rt == NULL) return; /* If we didn't get a host route, allocate one */ if ((rt->rt_flags & RTF_HOST) == 0) { struct rtentry *nrt; error = rtrequest(RTM_ADD, dst, rt->rt_gateway, NULL, RTF_GATEWAY | RTF_HOST | RTF_DYNAMIC, &nrt); if (error) { rt_unref(rt); return; } nrt->rt_rmx = rt->rt_rmx; rt_newmsg_dynamic(RTM_ADD, nrt); rt_unref(rt); rt = nrt; } mutex_enter(&icmp_mtx); error = rt_timer_add(rt, icmp_mtudisc_timeout, ip_mtudisc_timeout_q); mutex_exit(&icmp_mtx); if (error) { rt_unref(rt); return; } if (mtu == 0) { int i = 0; mtu = ntohs(icp->icmp_ip.ip_len); /* Some 4.2BSD-based routers incorrectly adjust the ip_len */ if (mtu > rt->rt_rmx.rmx_mtu && rt->rt_rmx.rmx_mtu != 0) mtu -= (icp->icmp_ip.ip_hl << 2); /* If we still can't guess a value, try the route */ if (mtu == 0) { mtu = rt->rt_rmx.rmx_mtu; /* If no route mtu, default to the interface mtu */ if (mtu == 0) mtu = rt->rt_ifp->if_mtu; } for (i = 0; i < sizeof(mtu_table) / sizeof(mtu_table[0]); i++) { if (mtu > mtu_table[i]) { mtu = mtu_table[i]; break; } } } /* * XXX: RTV_MTU is overloaded, since the admin can set it * to turn off PMTU for a route, and the kernel can * set it to indicate a serious problem with PMTU * on a route. We should be using a separate flag * for the kernel to indicate this. */ if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { if (mtu < 296 || mtu > rt->rt_ifp->if_mtu) rt->rt_rmx.rmx_locks |= RTV_MTU; else if (rt->rt_rmx.rmx_mtu > mtu || rt->rt_rmx.rmx_mtu == 0) { ICMP_STATINC(ICMP_STAT_PMTUCHG); rt->rt_rmx.rmx_mtu = mtu; } } if (rt != NULL) rt_unref(rt); /* * Notify protocols that the MTU for this destination * has changed. */ mutex_enter(&icmp_mtx); for (mc = LIST_FIRST(&icmp_mtudisc_callbacks); mc != NULL; mc = LIST_NEXT(mc, mc_list)) (*mc->mc_func)(faddr); mutex_exit(&icmp_mtx); } /* * Return the next larger or smaller MTU plateau (table from RFC 1191) * given current value MTU. If DIR is less than zero, a larger plateau * is returned; otherwise, a smaller value is returned. */ u_int ip_next_mtu(u_int mtu, int dir) /* XXX unused */ { int i; for (i = 0; i < (sizeof mtu_table) / (sizeof mtu_table[0]); i++) { if (mtu >= mtu_table[i]) break; } if (dir < 0) { if (i == 0) { return 0; } else { return mtu_table[i - 1]; } } else { if (mtu_table[i] == 0) { return 0; } else if (mtu > mtu_table[i]) { return mtu_table[i]; } else { return mtu_table[i + 1]; } } } static void icmp_mtudisc_timeout(struct rtentry *rt, struct rttimer *r) { struct rtentry *retrt; KASSERT(rt != NULL); rt_assert_referenced(rt); if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) == (RTF_DYNAMIC | RTF_HOST)) { rtrequest(RTM_DELETE, rt_getkey(rt), rt->rt_gateway, rt_mask(rt), rt->rt_flags, &retrt); rt_newmsg_dynamic(RTM_DELETE, retrt); rt_unref(rt); rt_free(retrt); } else { if ((rt->rt_rmx.rmx_locks & RTV_MTU) == 0) { rt->rt_rmx.rmx_mtu = 0; } } } static void icmp_redirect_timeout(struct rtentry *rt, struct rttimer *r) { struct rtentry *retrt; KASSERT(rt != NULL); rt_assert_referenced(rt); if ((rt->rt_flags & (RTF_DYNAMIC | RTF_HOST)) == (RTF_DYNAMIC | RTF_HOST)) { rtrequest(RTM_DELETE, rt_getkey(rt), rt->rt_gateway, rt_mask(rt), rt->rt_flags, &retrt); rt_newmsg_dynamic(RTM_DELETE, retrt); rt_unref(rt); rt_free(retrt); } } /* * Perform rate limit check. * Returns 0 if it is okay to send the icmp packet. * Returns 1 if the router SHOULD NOT send this icmp packet due to rate * limitation. * * XXX per-destination/type check necessary? */ int icmp_ratelimit(const struct in_addr *dst, const int type, const int code) { /* PPS limit */ if (!ppsratecheck(&icmperrppslim_last, &icmperrpps_count, icmperrppslim)) { /* The packet is subject to rate limit */ return 1; } /* okay to send */ return 0; }