/* $NetBSD: mpls_ttl.c,v 1.15 2018/12/27 14:03:55 maxv Exp $ */ /* * Copyright (c) 2010 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. * * This code is derived from software contributed to The NetBSD Foundation * by Mihai Chelaru <kefren@NetBSD.org> * * 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 <sys/cdefs.h> __KERNEL_RCSID(0, "$NetBSD: mpls_ttl.c,v 1.15 2018/12/27 14:03:55 maxv Exp $"); #ifdef _KERNEL_OPT #include "opt_inet.h" #include "opt_mpls.h" #endif #include <sys/param.h> #include <sys/malloc.h> #include <sys/mbuf.h> #include <sys/errno.h> #include <sys/socket.h> #include <sys/systm.h> #include <net/if.h> #include <net/if_dl.h> #include <netinet/in.h> #include <netinet/in_systm.h> #include <netinet/ip.h> #include <netinet/ip_icmp.h> #include <netinet/icmp_private.h> #include <netinet/icmp_var.h> #include <netmpls/mpls.h> #include <netmpls/mpls_var.h> #ifdef INET /* in netinet/ip_icmp.c */ extern int icmpreturndatabytes; /* ICMP Extensions */ #define MPLS_STACK_ENTRY_CLASS 1 #define MPLS_STACK_ENTRY_C_TYPE 1 struct mpls_extension { struct icmp_ext_hdr cmn_hdr; struct icmp_ext_obj_hdr obj_hdr; union mpls_shim ms; } __packed; static void mpls_icmp_error(struct mbuf *, int, int, n_long, int, union mpls_shim *); static struct mbuf *ip4_check(struct mbuf *); /* * Send an ICMP Extended error message. References: RFC4884 and RFC4950. * * XXX: This code is inspired from icmp_error(), and should really be merged * into it. icmp_error() should handle ICMP Extended error messages. * * XXX: It is called only for ICMP_TIMXCEED_INTRANS but code is too general. * * XXX: We're not setting the 'length' field of the Extended ICMP header. * According to RFC4884, we are in 'non-compliant' mode. Moreover, we're * not computing the checksum of the Extended ICMP header. */ static void mpls_icmp_error(struct mbuf *n, int type, int code, n_long dest, int destmtu, union mpls_shim *shim) { struct ip *oip = mtod(n, struct ip *), *nip; unsigned oiplen = oip->ip_hl << 2; struct icmp *icp; struct mbuf *m; unsigned icmplen, mblen, packetlen; struct mpls_extension mpls_icmp_ext; memset(&mpls_icmp_ext, 0, sizeof(mpls_icmp_ext)); mpls_icmp_ext.cmn_hdr.version = ICMP_EXT_VERSION; mpls_icmp_ext.cmn_hdr.checksum = 0; /* XXX */ mpls_icmp_ext.obj_hdr.length = htons(sizeof(union mpls_shim) + sizeof(struct icmp_ext_obj_hdr)); mpls_icmp_ext.obj_hdr.class_num = MPLS_STACK_ENTRY_CLASS; mpls_icmp_ext.obj_hdr.c_type = MPLS_STACK_ENTRY_C_TYPE; mpls_icmp_ext.ms.s_addr = shim->s_addr; if (type != ICMP_REDIRECT) ICMP_STATINC(ICMP_STAT_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 *)((char *)oip + oiplen))->icmp_type)) { ICMP_STATINC(ICMP_STAT_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, do a rate limitation check. */ if (icmp_ratelimit(&oip->ip_src, type, code)) /* XXX stats */ goto freeit; /* * Now, formulate icmp message */ icmplen = uimin(ICMP_EXT_OFFSET, ntohs(oip->ip_len)); /* * Defend against mbuf chains shorter than oip->ip_len - oiplen: */ mblen = 0; for (m = n; m && (mblen < icmplen); m = m->m_next) mblen += m->m_len; icmplen = uimin(mblen, icmplen); packetlen = sizeof(struct ip) + offsetof(struct icmp, icmp_ip) + ICMP_EXT_OFFSET + sizeof(mpls_icmp_ext); /* * 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 below in * icmp_sysctl will keep things below that limit. */ KASSERT(packetlen <= MCLBYTES); m = m_gethdr(M_DONTWAIT, MT_HEADER); if (m && (packetlen > 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 = packetlen; if ((m->m_flags & M_EXT) == 0) m_align(m, m->m_len); m->m_data += sizeof(struct ip); m->m_len -= sizeof(struct ip); icp = mtod(m, struct icmp *); if ((u_int)type > ICMP_MAXTYPE) panic("icmp error (mpls_ttl)"); ICMP_STATINC(ICMP_STAT_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; memset(&icp->icmp_ip, 0, ICMP_EXT_OFFSET); m_copydata(n, 0, icmplen, (char *)&icp->icmp_ip); /* Append the extension structure */ memcpy(((char*)&icp->icmp_ip) + ICMP_EXT_OFFSET, &mpls_icmp_ext, sizeof(mpls_icmp_ext)); /* * Now, copy old ip header (without options) * in front of icmp message. */ if ((m->m_flags & M_EXT) == 0 && 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_copy_rcvif(m, n); nip = mtod(m, struct ip *); /* 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; icmp_reflect(m); freeit: m_freem(n); } static struct mbuf * ip4_check(struct mbuf *m) { struct ip *iph; int hlen, len; if (m->m_len < sizeof(struct ip) && (m = m_pullup(m, sizeof(struct ip))) == NULL) return NULL; iph = mtod(m, struct ip *); if (iph->ip_v != IPVERSION) goto freeit; hlen = iph->ip_hl << 2; if (hlen < sizeof(struct ip)) goto freeit; if (hlen > m->m_len) { if ((m = m_pullup(m, hlen)) == NULL) return NULL; iph = mtod(m, struct ip *); } /* * RFC1122: packets with a multicast source address are * not allowed. * RFC1122: 127/8 must not appear on wire. */ if (IN_MULTICAST(iph->ip_src.s_addr) || (ntohl(iph->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || (ntohl(iph->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET || in_cksum(m, hlen) != 0) goto freeit; len = ntohs(iph->ip_len); if (len < hlen || m->m_pkthdr.len < len) goto freeit; return m; freeit: m_freem(m); return NULL; } #endif /* INET */ struct mbuf * mpls_ttl_dec(struct mbuf *m) { union mpls_shim *mshim; #ifdef INET union mpls_shim top_shim, bos_shim; #endif if (__predict_false(m->m_len < sizeof(union mpls_shim) && (m = m_pullup(m, sizeof(union mpls_shim))) == NULL)) return NULL; mshim = mtod(m, union mpls_shim *); mshim->s_addr = ntohl(mshim->s_addr); mshim->shim.ttl--; if (mshim->shim.ttl == 0) { if (!mpls_icmp_respond) { m_freem(m); return NULL; } #ifdef INET /* * Shim ttl exceeded. Send back ICMP type 11 code 0. */ bos_shim.s_addr = mshim->s_addr; top_shim.s_addr = htonl(mshim->s_addr); m_adj(m, sizeof(union mpls_shim)); /* Goto BOS */ while (bos_shim.shim.bos == 0) { if (m->m_len < sizeof(union mpls_shim) && (m = m_pullup(m, sizeof(union mpls_shim))) == NULL) { m_freem(m); return NULL; } bos_shim.s_addr = ntohl(mtod(m, union mpls_shim *)->s_addr); m_adj(m, sizeof(union mpls_shim)); } if ((m = ip4_check(m)) != NULL) mpls_icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 0, 0, &top_shim); #else m_freem(m); #endif return NULL; } mshim->s_addr = htonl(mshim->s_addr); return m; }
