/* * 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 * $FreeBSD: src/sys/netinet/ip_icmp.c,v 1.39.2.19 2003/01/24 05:11:34 sam Exp $ */ #include "opt_icmpprintfs.h" #include #include #include /* for M_NOWAIT */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define _IP_VHL #include #include #include #include #include #include #include /* * ICMP routines: error generation, receive packet processing, and * routines to turnaround packets back to the originator, and * host table maintenance routines. */ struct icmpstat icmpstat; SYSCTL_STRUCT(_net_inet_icmp, ICMPCTL_STATS, stats, CTLFLAG_RW, &icmpstat, icmpstat, "ICMP statistics"); static int icmpmaskrepl = 0; SYSCTL_INT(_net_inet_icmp, ICMPCTL_MASKREPL, maskrepl, CTLFLAG_RW, &icmpmaskrepl, 0, "Allow replies to netmask requests"); static int drop_redirect = 0; SYSCTL_INT(_net_inet_icmp, OID_AUTO, drop_redirect, CTLFLAG_RW, &drop_redirect, 0, "Ignore ICMP redirects"); static int log_redirect = 0; SYSCTL_INT(_net_inet_icmp, OID_AUTO, log_redirect, CTLFLAG_RW, &log_redirect, 0, "Enable output about ICMP redirects"); static int discard_sourcequench = 1; SYSCTL_INT(_net_inet_icmp, OID_AUTO, discard_sourcequench, CTLFLAG_RW, &discard_sourcequench, 0, "Discard ICMP Source Quench"); #ifdef ICMP_BANDLIM /* * ICMP error-response bandwidth limiting sysctl. If not enabled, sysctl * variable content is -1 and read-only. */ static int icmplim = 200; SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RW, &icmplim, 0, "ICMP bandwidth limit"); #else static int icmplim = -1; SYSCTL_INT(_net_inet_icmp, ICMPCTL_ICMPLIM, icmplim, CTLFLAG_RD, &icmplim, 0, "ICMP bandwidth limit"); #endif static int icmplim_output = 0; SYSCTL_INT(_net_inet_icmp, OID_AUTO, icmplim_output, CTLFLAG_RW, &icmplim_output, 0, "Enable output about ICMP bandwidth limits"); /* * ICMP broadcast echo sysctl */ static int icmpbmcastecho = 0; SYSCTL_INT(_net_inet_icmp, OID_AUTO, bmcastecho, CTLFLAG_RW, &icmpbmcastecho, 0, ""); static char icmp_reply_src[IFNAMSIZ]; SYSCTL_STRING(_net_inet_icmp, OID_AUTO, reply_src, CTLFLAG_RW, icmp_reply_src, IFNAMSIZ, "icmp reply source for non-local packets."); static int icmp_rfi; SYSCTL_INT(_net_inet_icmp, OID_AUTO, reply_from_interface, CTLFLAG_RW, &icmp_rfi, 0, "ICMP reply from incoming interface for " "non-local packets"); #ifdef ICMPPRINTFS static int icmpprintfs = 0; SYSCTL_INT(_net_inet_icmp, OID_AUTO, debug_prints, CTLFLAG_RW, &icmpprintfs, 0, "extra ICMP debug prints"); #endif static void icmp_reflect (struct mbuf *); static void icmp_send (struct mbuf *, struct mbuf *, struct route *); extern struct protosw inetsw[]; /* * Generate an error packet of type error * in response to bad packet ip. */ void icmp_error(struct mbuf *n, int type, int code, n_long dest, int destmtu) { struct ip *oip = mtod(n, struct ip *), *nip; unsigned oiplen = IP_VHL_HL(oip->ip_vhl) << 2; struct icmp *icp; struct mbuf *m; unsigned icmplen; #ifdef ICMPPRINTFS if (icmpprintfs) kprintf("icmp_error(%p, %d, %d)\n", oip, type, code); #endif if (type != ICMP_REDIRECT) icmpstat.icps_error++; /* * Don't send error if the original packet was encrypted. * Don't send error if not the first fragment of message. * Don't error if the old packet protocol was ICMP * error message, only known informational types. */ if (n->m_flags & M_DECRYPTED) 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 >= oiplen + ICMP_MINLEN && !ICMP_INFOTYPE(((struct icmp *)((caddr_t)oip + oiplen))->icmp_type)) { icmpstat.icps_oldicmp++; goto freeit; } /* Don't send error in response to a multicast or broadcast packet */ if (n->m_flags & (M_BCAST|M_MCAST)) goto freeit; /* * First, formulate icmp message */ m = m_gethdr(M_NOWAIT, MT_HEADER); if (m == NULL) goto freeit; icmplen = min(oiplen + 8, ntohs(oip->ip_len)); if (icmplen < sizeof(struct ip)) panic("icmp_error: bad length"); m->m_len = icmplen + ICMP_MINLEN; MH_ALIGN(m, m->m_len); icp = mtod(m, struct icmp *); if ((u_int)type > ICMP_MAXTYPE) panic("icmp_error"); icmpstat.icps_outhist[type]++; 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, icmplen, &icp->icmp_ip); nip = &icp->icmp_ip; /* * Now, copy old ip header (without options) * in front of icmp message. */ if (m->m_data - sizeof(struct ip) < m->m_pktdat) panic("icmp len"); m->m_data -= sizeof(struct ip); m->m_len += sizeof(struct ip); m->m_pkthdr.len = m->m_len; m->m_pkthdr.rcvif = n->m_pkthdr.rcvif; nip = mtod(m, struct ip *); bcopy(oip, nip, sizeof(struct ip)); nip->ip_len = htons(m->m_len); nip->ip_vhl = IP_VHL_BORING; nip->ip_p = IPPROTO_ICMP; nip->ip_tos = 0; m->m_pkthdr.fw_flags |= n->m_pkthdr.fw_flags & FW_MBUF_GENERATED; icmp_reflect(m); freeit: m_freem(n); } static void icmp_ctlinput_done_handler(netmsg_t nmsg) { struct netmsg_ctlinput *msg = (struct netmsg_ctlinput *)nmsg; struct mbuf *m = msg->m; int hlen = msg->hlen; rip_input(&m, &hlen, msg->proto); } static void icmp_ctlinput_done(struct mbuf *m) { struct netmsg_ctlinput *msg = &m->m_hdr.mh_ctlmsg; netmsg_init(&msg->base, NULL, &netisr_apanic_rport, 0, icmp_ctlinput_done_handler); lwkt_sendmsg(netisr_cpuport(0), &msg->base.lmsg); } static void icmp_mtudisc(struct mbuf *m, int hlen) { struct sockaddr_in icmpsrc = { sizeof(struct sockaddr_in), AF_INET }; struct rtentry *rt; struct icmp *icp; KASSERT(curthread->td_type == TD_TYPE_NETISR, ("not in netisr")); icp = mtodoff(m, struct icmp *, hlen); icmpsrc.sin_addr = icp->icmp_ip.ip_dst; /* * MTU discovery: * If we got a needfrag and there is a host route to the original * destination, and the MTU is not locked, then set the MTU in the * route to the suggested new value (if given) and then notify as * usual. The ULPs will notice that the MTU has changed and adapt * accordingly. If no new MTU was suggested, then we guess a new * one less than the current value. If the new MTU is unreasonably * small (arbitrarily set at 296), then we reset the MTU to the * interface value and enable the lock bit, indicating that we are * no longer doing MTU discovery. */ rt = rtpurelookup((struct sockaddr *)&icmpsrc); if (rt != NULL && (rt->rt_flags & RTF_HOST) && !(rt->rt_rmx.rmx_locks & RTV_MTU)) { #ifdef DEBUG_MTUDISC char src_buf[INET_ADDRSTRLEN]; #endif int mtu; mtu = ntohs(icp->icmp_nextmtu); if (!mtu) mtu = ip_next_mtu(rt->rt_rmx.rmx_mtu, 1); #ifdef DEBUG_MTUDISC kprintf("MTU for %s reduced to %d\n", inet_ntop(AF_INET, &icmpsrc.sin_addr, src_buf, INET_ADDRSTRLEN), mtu); #endif if (mtu < 296) { /* rt->rt_rmx.rmx_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 = mtu; } } if (rt != NULL) --rt->rt_refcnt; /* * XXX if the packet contains [IPv4 AH TCP], we can't make a * notification to TCP layer. */ so_pr_ctlinput_direct(&inetsw[ip_protox[icp->icmp_ip.ip_p]], PRC_MSGSIZE, (struct sockaddr *)&icmpsrc, &icp->icmp_ip); } static void icmp_mtudisc_handler(netmsg_t nmsg) { struct netmsg_ctlinput *msg = (struct netmsg_ctlinput *)nmsg; int nextcpu; ASSERT_NETISR_NCPUS(mycpuid); icmp_mtudisc(msg->m, msg->hlen); nextcpu = mycpuid + 1; if (nextcpu < netisr_ncpus) lwkt_forwardmsg(netisr_cpuport(nextcpu), &msg->base.lmsg); else icmp_ctlinput_done(msg->m); } static boolean_t icmp_mtudisc_start(struct mbuf *m, int hlen, int proto) { struct netmsg_ctlinput *msg; ASSERT_NETISR0; icmp_mtudisc(m, hlen); if (netisr_ncpus == 1) { /* There is only one netisr; done */ return FALSE; } msg = &m->m_hdr.mh_ctlmsg; netmsg_init(&msg->base, NULL, &netisr_apanic_rport, 0, icmp_mtudisc_handler); msg->m = m; msg->cmd = PRC_MSGSIZE; msg->hlen = hlen; msg->proto = proto; lwkt_sendmsg(netisr_cpuport(1), &msg->base.lmsg); return TRUE; } static void icmp_ctlinput(struct mbuf *m, int cmd, int hlen) { struct sockaddr_in icmpsrc = { sizeof(struct sockaddr_in), AF_INET }; struct icmp *icp; KASSERT(curthread->td_type == TD_TYPE_NETISR, ("not in netisr")); icp = mtodoff(m, struct icmp *, hlen); icmpsrc.sin_addr = icp->icmp_ip.ip_dst; /* * XXX if the packet contains [IPv4 AH TCP], we can't make a * notification to TCP layer. */ so_pr_ctlinput_direct(&inetsw[ip_protox[icp->icmp_ip.ip_p]], cmd, (struct sockaddr *)&icmpsrc, &icp->icmp_ip); } static void icmp_ctlinput_handler(netmsg_t nmsg) { struct netmsg_ctlinput *msg = (struct netmsg_ctlinput *)nmsg; ASSERT_NETISR_NCPUS(mycpuid); icmp_ctlinput(msg->m, msg->cmd, msg->hlen); icmp_ctlinput_done(msg->m); } static void icmp_ctlinput_start(struct mbuf *m, struct lwkt_port *port, int cmd, int hlen, int proto) { struct netmsg_ctlinput *msg; KASSERT(&curthread->td_msgport != port, ("send icmp ctlinput to the current netisr")); msg = &m->m_hdr.mh_ctlmsg; netmsg_init(&msg->base, NULL, &netisr_apanic_rport, 0, icmp_ctlinput_handler); msg->m = m; msg->cmd = cmd; msg->hlen = hlen; msg->proto = proto; lwkt_sendmsg(port, &msg->base.lmsg); } static void icmp_ctlinput_global_handler(netmsg_t nmsg) { struct netmsg_ctlinput *msg = (struct netmsg_ctlinput *)nmsg; int nextcpu; ASSERT_NETISR_NCPUS(mycpuid); icmp_ctlinput(msg->m, msg->cmd, msg->hlen); nextcpu = mycpuid + 1; if (nextcpu < netisr_ncpus) lwkt_forwardmsg(netisr_cpuport(nextcpu), &msg->base.lmsg); else icmp_ctlinput_done(msg->m); } static void icmp_ctlinput_global_start(struct mbuf *m, int cmd, int hlen, int proto) { struct netmsg_ctlinput *msg; ASSERT_NETISR0; KASSERT(netisr_ncpus > 1, ("there is only 1 netisr cpu")); icmp_ctlinput(m, cmd, hlen); msg = &m->m_hdr.mh_ctlmsg; netmsg_init(&msg->base, NULL, &netisr_apanic_rport, 0, icmp_ctlinput_global_handler); msg->m = m; msg->cmd = cmd; msg->hlen = hlen; msg->proto = proto; lwkt_sendmsg(netisr_cpuport(1), &msg->base.lmsg); } #define ICMP_RTREDIRECT_FLAGS (RTF_GATEWAY | RTF_HOST) static void icmp_redirect(struct mbuf *m, int hlen, boolean_t prt) { struct sockaddr_in icmpsrc = { sizeof(struct sockaddr_in), AF_INET }; struct sockaddr_in icmpdst = { sizeof(struct sockaddr_in), AF_INET }; struct sockaddr_in icmpgw = { sizeof(struct sockaddr_in), AF_INET }; struct icmp *icp; struct ip *ip; KASSERT(curthread->td_type == TD_TYPE_NETISR, ("not in netisr")); ip = mtod(m, struct ip *); icp = mtodoff(m, struct icmp *, hlen); /* * 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). */ #ifdef ICMPPRINTFS if (icmpprintfs && prt) { char dst_buf[INET_ADDRSTRLEN], gw_buf[INET_ADDRSTRLEN]; kprintf("redirect dst %s to %s\n", inet_ntop(AF_INET, &icp->icmp_ip.ip_dst, dst_buf, INET_ADDRSTRLEN), inet_ntop(AF_INET, &icp->icmp_gwaddr, gw_buf, INET_ADDRSTRLEN)); } #endif icmpgw.sin_addr = ip->ip_src; icmpdst.sin_addr = icp->icmp_gwaddr; icmpsrc.sin_addr = icp->icmp_ip.ip_dst; rtredirect_oncpu((struct sockaddr *)&icmpsrc, (struct sockaddr *)&icmpdst, NULL, ICMP_RTREDIRECT_FLAGS, (struct sockaddr *)&icmpgw); kpfctlinput_direct(PRC_REDIRECT_HOST, (struct sockaddr *)&icmpsrc); } static void icmp_redirect_done_handler(netmsg_t nmsg) { struct netmsg_ctlinput *msg = (struct netmsg_ctlinput *)nmsg; struct mbuf *m = msg->m; int hlen = msg->hlen; rip_input(&m, &hlen, msg->proto); } static void icmp_redirect_done(struct mbuf *m, int hlen, boolean_t dispatch_rip) { struct rt_addrinfo rtinfo; struct sockaddr_in icmpsrc = { sizeof(struct sockaddr_in), AF_INET }; struct sockaddr_in icmpdst = { sizeof(struct sockaddr_in), AF_INET }; struct sockaddr_in icmpgw = { sizeof(struct sockaddr_in), AF_INET }; struct icmp *icp; struct ip *ip; ip = mtod(m, struct ip *); icp = mtodoff(m, struct icmp *, hlen); icmpgw.sin_addr = ip->ip_src; icmpdst.sin_addr = icp->icmp_gwaddr; icmpsrc.sin_addr = icp->icmp_ip.ip_dst; bzero(&rtinfo, sizeof(struct rt_addrinfo)); rtinfo.rti_info[RTAX_DST] = (struct sockaddr *)&icmpsrc; rtinfo.rti_info[RTAX_GATEWAY] = (struct sockaddr *)&icmpdst; rtinfo.rti_info[RTAX_NETMASK] = NULL; rtinfo.rti_info[RTAX_AUTHOR] = (struct sockaddr *)&icmpgw; rt_missmsg(RTM_REDIRECT, &rtinfo, ICMP_RTREDIRECT_FLAGS, 0); if (dispatch_rip) { struct netmsg_ctlinput *msg = &m->m_hdr.mh_ctlmsg; netmsg_init(&msg->base, NULL, &netisr_apanic_rport, 0, icmp_redirect_done_handler); lwkt_sendmsg(netisr_cpuport(0), &msg->base.lmsg); } } static void icmp_redirect_handler(netmsg_t nmsg) { struct netmsg_ctlinput *msg = (struct netmsg_ctlinput *)nmsg; int nextcpu; ASSERT_NETISR_NCPUS(mycpuid); icmp_redirect(msg->m, msg->hlen, FALSE); nextcpu = mycpuid + 1; if (nextcpu < netisr_ncpus) lwkt_forwardmsg(netisr_cpuport(nextcpu), &msg->base.lmsg); else icmp_redirect_done(msg->m, msg->hlen, TRUE); } static boolean_t icmp_redirect_start(struct mbuf *m, int hlen, int proto) { struct netmsg_ctlinput *msg; ASSERT_NETISR0; icmp_redirect(m, hlen, TRUE); if (netisr_ncpus == 1) { /* There is only one netisr; done */ icmp_redirect_done(m, hlen, FALSE); return FALSE; } msg = &m->m_hdr.mh_ctlmsg; netmsg_init(&msg->base, NULL, &netisr_apanic_rport, 0, icmp_redirect_handler); msg->m = m; msg->cmd = PRC_REDIRECT_HOST; msg->hlen = hlen; msg->proto = proto; lwkt_sendmsg(netisr_cpuport(1), &msg->base.lmsg); return TRUE; } /* * Process a received ICMP message. */ int icmp_input(struct mbuf **mp, int *offp, int proto) { struct sockaddr_in icmpsrc = { sizeof(struct sockaddr_in), AF_INET }; struct sockaddr_in icmpdst = { sizeof(struct sockaddr_in), AF_INET }; struct icmp *icp; struct in_ifaddr *ia; struct mbuf *m = *mp; struct ip *ip; int icmplen; int i, hlen; int code; ASSERT_NETISR0; *mp = NULL; hlen = *offp; ip = mtod(m, struct ip *); icmplen = ntohs(ip->ip_len) - hlen; /* * Locate icmp structure in mbuf, and check * that not corrupted and of at least minimum length. */ #ifdef ICMPPRINTFS if (icmpprintfs) { char src_buf[INET_ADDRSTRLEN], dst_buf[INET_ADDRSTRLEN]; kprintf("icmp_input from %s to %s, len %d\n", inet_ntop(AF_INET, &ip->ip_src, src_buf, INET_ADDRSTRLEN), inet_ntop(AF_INET, &ip->ip_dst, dst_buf, INET_ADDRSTRLEN), icmplen); } #endif if (icmplen < ICMP_MINLEN) { icmpstat.icps_tooshort++; goto freeit; } i = hlen + min(icmplen, ICMP_ADVLENMIN); if (m->m_len < i && (m = m_pullup(m, i)) == NULL) { icmpstat.icps_tooshort++; return(IPPROTO_DONE); } ip = mtod(m, struct ip *); if (in_cksum_skip(m, hlen + icmplen, hlen)) { icmpstat.icps_checksum++; goto freeit; } icp = (struct icmp *)((caddr_t)ip + hlen); #ifdef ICMPPRINTFS if (icmpprintfs) kprintf("icmp_input, type %d code %d\n", icp->icmp_type, icp->icmp_code); #endif /* * Message type specific processing. */ if (icp->icmp_type > ICMP_MAXTYPE) goto raw; icmpstat.icps_inhist[icp->icmp_type]++; code = icp->icmp_code; switch (icp->icmp_type) { case ICMP_UNREACH: switch (code) { case ICMP_UNREACH_NET: case ICMP_UNREACH_HOST: case ICMP_UNREACH_SRCFAIL: case ICMP_UNREACH_NET_UNKNOWN: case ICMP_UNREACH_HOST_UNKNOWN: case ICMP_UNREACH_ISOLATED: case ICMP_UNREACH_TOSNET: case ICMP_UNREACH_TOSHOST: case ICMP_UNREACH_HOST_PRECEDENCE: case ICMP_UNREACH_PRECEDENCE_CUTOFF: code = PRC_UNREACH_NET; break; case ICMP_UNREACH_NEEDFRAG: code = PRC_MSGSIZE; break; /* * RFC 1122, Sections 3.2.2.1 and 4.2.3.9. * Treat subcodes 2,3 as immediate RST */ case ICMP_UNREACH_PROTOCOL: case ICMP_UNREACH_PORT: code = PRC_UNREACH_PORT; break; case ICMP_UNREACH_NET_PROHIB: case ICMP_UNREACH_HOST_PROHIB: case ICMP_UNREACH_FILTER_PROHIB: code = PRC_UNREACH_ADMIN_PROHIB; 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; if (discard_sourcequench) break; code = PRC_QUENCH; deliver: /* * Problem with datagram; advise higher level routines. */ if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) { icmpstat.icps_badlen++; goto freeit; } /* Discard ICMP's in response to multicast packets */ if (IN_MULTICAST(ntohl(icp->icmp_ip.ip_dst.s_addr))) goto badcode; #ifdef ICMPPRINTFS if (icmpprintfs) kprintf("deliver to protocol %d\n", icp->icmp_ip.ip_p); #endif icmpsrc.sin_addr = icp->icmp_ip.ip_dst; /* * MTU discovery */ if (code == PRC_MSGSIZE) { /* Run MTU discovery in all netisrs */ if (icmp_mtudisc_start(m, hlen, proto)) { /* Forwarded; done */ return IPPROTO_DONE; } /* Move on; run rip_input() directly */ } else { struct protosw *pr; struct lwkt_port *port; int cpu; pr = &inetsw[ip_protox[icp->icmp_ip.ip_p]]; port = so_pr_ctlport(pr, code, (struct sockaddr *)&icmpsrc, &icp->icmp_ip, &cpu); if (port != NULL) { if (cpu == netisr_ncpus) { if (netisr_ncpus > 1) { /* * Run pr_ctlinput in all * netisrs */ icmp_ctlinput_global_start(m, code, hlen, proto); return IPPROTO_DONE; } /* * There is only one netisr; run * pr_ctlinput directly. */ } else if (cpu != mycpuid) { /* * Send to the target netisr to run * pr_ctlinput. */ icmp_ctlinput_start(m, port, code, hlen, proto); return IPPROTO_DONE; } /* * The target netisr is this netisr. * * XXX if the packet contains [IPv4 AH TCP], * we can't make a notification to TCP layer. */ so_pr_ctlinput_direct(pr, code, (struct sockaddr *)&icmpsrc, &icp->icmp_ip); } /* Move on; run rip_input() directly */ } break; badcode: icmpstat.icps_badcode++; break; case ICMP_ECHO: if (!icmpbmcastecho && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { icmpstat.icps_bmcastecho++; break; } icp->icmp_type = ICMP_ECHOREPLY; #ifdef ICMP_BANDLIM if (badport_bandlim(BANDLIM_ICMP_ECHO) < 0) goto freeit; else #endif goto reflect; case ICMP_TSTAMP: if (!icmpbmcastecho && (m->m_flags & (M_MCAST | M_BCAST)) != 0) { icmpstat.icps_bmcasttstamp++; break; } if (icmplen < ICMP_TSLEN) { icmpstat.icps_badlen++; break; } icp->icmp_type = ICMP_TSTAMPREPLY; icp->icmp_rtime = iptime(); icp->icmp_ttime = icp->icmp_rtime; /* bogus, do later! */ #ifdef ICMP_BANDLIM if (badport_bandlim(BANDLIM_ICMP_TSTAMP) < 0) goto freeit; else #endif goto reflect; case ICMP_MASKREQ: 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) break; switch (ip->ip_dst.s_addr) { case INADDR_BROADCAST: case INADDR_ANY: icmpdst.sin_addr = ip->ip_src; break; default: icmpdst.sin_addr = ip->ip_dst; } ia = (struct in_ifaddr *)ifaof_ifpforaddr( (struct sockaddr *)&icmpdst, m->m_pkthdr.rcvif); if (ia == NULL) break; if (ia->ia_ifp == 0) break; icp->icmp_type = ICMP_MASKREPLY; icp->icmp_mask = ia->ia_sockmask.sin_addr.s_addr; if (ip->ip_src.s_addr == 0) { if (ia->ia_ifp->if_flags & IFF_BROADCAST) ip->ip_src = satosin(&ia->ia_broadaddr)->sin_addr; else if (ia->ia_ifp->if_flags & IFF_POINTOPOINT) ip->ip_src = satosin(&ia->ia_dstaddr)->sin_addr; } reflect: icmpstat.icps_reflect++; icmpstat.icps_outhist[icp->icmp_type]++; icmp_reflect(m); return(IPPROTO_DONE); case ICMP_REDIRECT: if (log_redirect) { char src_buf[INET_ADDRSTRLEN]; char dst_buf[INET_ADDRSTRLEN]; char gwy_buf[INET_ADDRSTRLEN]; kprintf("icmp redirect from %s: %s => %s\n", inet_ntop(AF_INET, &ip->ip_src, src_buf, INET_ADDRSTRLEN), inet_ntop(AF_INET, &icp->icmp_ip.ip_dst, dst_buf, INET_ADDRSTRLEN), inet_ntop(AF_INET, &icp->icmp_gwaddr, gwy_buf, INET_ADDRSTRLEN)); } if (drop_redirect) break; if (code > 3) goto badcode; if (icmplen < ICMP_ADVLENMIN || icmplen < ICMP_ADVLEN(icp) || IP_VHL_HL(icp->icmp_ip.ip_vhl) < (sizeof(struct ip) >> 2)) { icmpstat.icps_badlen++; break; } #ifdef ICMPPRINTFS if (icmpprintfs) { char dst_buf[INET_ADDRSTRLEN], gw_buf[INET_ADDRSTRLEN]; kprintf("redirect dst %s to %s\n", inet_ntop(AF_INET, &icp->icmp_ip.ip_dst, dst_buf, INET_ADDRSTRLEN), inet_ntop(AF_INET, &icp->icmp_gwaddr, gw_buf, INET_ADDRSTRLEN)); } #endif icmpsrc.sin_addr = icp->icmp_ip.ip_dst; /* Run redirect in all netisrs */ if (icmp_redirect_start(m, hlen, proto)) { /* Forwarded; done */ return IPPROTO_DONE; } /* Move on; run rip_input() directly */ 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: *mp = m; rip_input(mp, offp, proto); return(IPPROTO_DONE); freeit: m_freem(m); return(IPPROTO_DONE); } /* * Reflect the ip packet back to the source */ static void icmp_reflect(struct mbuf *m) { struct ip *ip = mtod(m, struct ip *); struct in_ifaddr *ia; struct in_ifaddr_container *iac; struct ifaddr_container *ifac; struct ifnet *ifp; struct in_addr t; struct mbuf *opts = NULL; int optlen = (IP_VHL_HL(ip->ip_vhl) << 2) - sizeof(struct ip); struct route *ro = NULL, rt; if (!in_canforward(ip->ip_src) && ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) != (IN_LOOPBACKNET << IN_CLASSA_NSHIFT))) { m_freem(m); /* Bad return address */ icmpstat.icps_badaddr++; goto done; /* Ip_output() will check for broadcast */ } t = ip->ip_dst; ip->ip_dst = ip->ip_src; ro = &rt; bzero(ro, sizeof *ro); /* * If the incoming packet was addressed directly to us, * use dst as the src for the reply. Otherwise (broadcast * or anonymous), use the address which corresponds * to the incoming interface. */ ia = NULL; LIST_FOREACH(iac, INADDR_HASH(t.s_addr), ia_hash) { if (t.s_addr == IA_SIN(iac->ia)->sin_addr.s_addr) { ia = iac->ia; goto match; } } ifp = m->m_pkthdr.rcvif; if (ifp != NULL && (ifp->if_flags & IFF_BROADCAST)) { TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) { struct ifaddr *ifa = ifac->ifa; if (ifa->ifa_addr->sa_family != AF_INET) continue; ia = ifatoia(ifa); if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr == t.s_addr) goto match; } } /* * If the packet was transiting through us, use the address of * the interface the packet came through in. If that interface * doesn't have a suitable IP address, the normal selection * criteria apply. */ if (icmp_rfi && ifp != NULL) { TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) { struct ifaddr *ifa = ifac->ifa; if (ifa->ifa_addr->sa_family != AF_INET) continue; ia = ifatoia(ifa); goto match; } } /* * If the incoming packet was not addressed directly to us, use * designated interface for icmp replies specified by sysctl * net.inet.icmp.reply_src (default not set). Otherwise continue * with normal source selection. */ if (icmp_reply_src[0] != '\0' && (ifp = ifunit_netisr(icmp_reply_src))) { TAILQ_FOREACH(ifac, &ifp->if_addrheads[mycpuid], ifa_link) { struct ifaddr *ifa = ifac->ifa; if (ifa->ifa_addr->sa_family != AF_INET) continue; ia = ifatoia(ifa); goto match; } } /* * If the packet was transiting through us, use the address of * the interface that is the closest to the packet source. * When we don't have a route back to the packet source, stop here * and drop the packet. */ ia = ip_rtaddr(ip->ip_dst, ro); if (ia == NULL) { m_freem(m); icmpstat.icps_noroute++; goto done; } match: t = IA_SIN(ia)->sin_addr; ip->ip_src = t; ip->ip_ttl = ip_defttl; 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_NOWAIT, MT_HEADER))) { opts->m_len = sizeof(struct in_addr); mtod(opts, struct in_addr *)->s_addr = 0; } if (opts) { #ifdef ICMPPRINTFS if (icmpprintfs) kprintf("icmp_reflect optlen %d rt %d => ", optlen, opts->m_len); #endif 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; } /* * Should check for overflow, but it * "can't happen". */ if (opt == IPOPT_RR || opt == IPOPT_TS || opt == IPOPT_SECURITY) { bcopy(cp, mtod(opts, caddr_t) + opts->m_len, len); opts->m_len += len; } } /* Terminate & pad, if necessary */ cnt = opts->m_len % 4; if (cnt) { for (; cnt < 4; cnt++) { *(mtod(opts, caddr_t) + opts->m_len) = IPOPT_EOL; opts->m_len++; } } #ifdef ICMPPRINTFS if (icmpprintfs) kprintf("%d\n", opts->m_len); #endif } /* * 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_vhl = IP_VHL_BORING; m->m_len -= optlen; if (m->m_flags & M_PKTHDR) m->m_pkthdr.len -= optlen; optlen += sizeof(struct ip); bcopy((caddr_t)ip + optlen, ip + 1, m->m_len - sizeof(struct ip)); } m->m_pkthdr.fw_flags &= FW_MBUF_GENERATED; m->m_flags &= ~(M_BCAST|M_MCAST); icmp_send(m, opts, ro); done: if (opts) m_free(opts); if (ro && ro->ro_rt) RTFREE(ro->ro_rt); } /* * Send an icmp packet back to the ip level, * after supplying a checksum. */ static void icmp_send(struct mbuf *m, struct mbuf *opts, struct route *rt) { struct ip *ip = mtod(m, struct ip *); struct icmp *icp; int hlen; hlen = IP_VHL_HL(ip->ip_vhl) << 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; m->m_pkthdr.rcvif = NULL; #ifdef ICMPPRINTFS if (icmpprintfs) { char dst_buf[INET_ADDRSTRLEN], src_buf[INET_ADDRSTRLEN]; kprintf("icmp_send dst %s src %s\n", inet_ntop(AF_INET, &ip->ip_dst, dst_buf, INET_ADDRSTRLEN), inet_ntop(AF_INET, &ip->ip_src, src_buf, INET_ADDRSTRLEN)); } #endif ip_output(m, opts, rt, 0, NULL, NULL); } n_time iptime(void) { struct timeval atv; u_long t; getmicrotime(&atv); t = (atv.tv_sec % (24*60*60)) * 1000 + atv.tv_usec / 1000; return (htonl(t)); } #if 1 /* * 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. */ int ip_next_mtu(int mtu, int dir) { static int mtutab[] = { 65535, 32000, 17914, 8166, 4352, 2002, 1492, 1006, 508, 296, 68, 0 }; int i; for (i = 0; i < (sizeof mtutab) / (sizeof mtutab[0]); i++) { if (mtu >= mtutab[i]) break; } if (dir < 0) { if (i == 0) { return 0; } else { return mtutab[i - 1]; } } else { if (mtutab[i] == 0) { return 0; } else if(mtu > mtutab[i]) { return mtutab[i]; } else { return mtutab[i + 1]; } } } #endif #ifdef ICMP_BANDLIM /* * badport_bandlim() - check for ICMP bandwidth limit * * Return 0 if it is ok to send an ICMP error response, -1 if we have * hit our bandwidth limit and it is not ok. * * If icmplim is <= 0, the feature is disabled and 0 is returned. * * For now we separate the TCP and UDP subsystems w/ different 'which' * values. We may eventually remove this separation (and simplify the * code further). * * Note that the printing of the error message is delayed so we can * properly print the icmp error rate that the system was trying to do * (i.e. 22000/100 pps, etc...). This can cause long delays in printing * the 'final' error, but it doesn't make sense to solve the printing * delay with more complex code. */ int badport_bandlim(int which) { static int lticks[BANDLIM_MAX + 1]; static int lpackets[BANDLIM_MAX + 1]; int dticks; const char *bandlimittype[] = { "Limiting icmp unreach response", "Limiting icmp ping response", "Limiting icmp tstamp response", "Limiting closed port RST response", "Limiting open port RST response" }; /* * Return ok status if feature disabled or argument out of * ranage. */ if (icmplim <= 0 || which > BANDLIM_MAX || which < 0) return(0); dticks = ticks - lticks[which]; /* * reset stats when cumulative dt exceeds one second. */ if ((unsigned int)dticks > hz) { if (lpackets[which] > icmplim && icmplim_output) { kprintf("%s from %d to %d packets per second\n", bandlimittype[which], lpackets[which], icmplim ); } lticks[which] = ticks; lpackets[which] = 0; } /* * bump packet count */ if (++lpackets[which] > icmplim) { return(-1); } return(0); } #endif