1 /* $OpenBSD: mpls_output.c,v 1.17 2014/07/22 11:06:10 mpi Exp $ */ 2 3 /* 4 * Copyright (c) 2008 Claudio Jeker <claudio@openbsd.org> 5 * Copyright (c) 2008 Michele Marchetto <michele@openbsd.org> 6 * 7 * Permission to use, copy, modify, and distribute this software for any 8 * purpose with or without fee is hereby granted, provided that the above 9 * copyright notice and this permission notice appear in all copies. 10 * 11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 18 */ 19 20 #include <sys/param.h> 21 #include <sys/mbuf.h> 22 #include <sys/systm.h> 23 #include <sys/socket.h> 24 25 #include <net/if.h> 26 #include <net/route.h> 27 28 #include <netmpls/mpls.h> 29 30 #ifdef INET 31 #include <netinet/in.h> 32 #include <netinet/ip.h> 33 #endif 34 35 #ifdef INET6 36 #include <netinet/ip6.h> 37 #endif 38 39 #ifdef MPLS_DEBUG 40 #define MPLS_LABEL_GET(l) ((ntohl((l) & MPLS_LABEL_MASK)) >> MPLS_LABEL_OFFSET) 41 #endif 42 43 void mpls_do_cksum(struct mbuf *); 44 u_int8_t mpls_getttl(struct mbuf *, sa_family_t); 45 46 int 47 mpls_output(struct ifnet *ifp0, struct mbuf *m, struct sockaddr *dst, 48 struct rtentry *rt0) 49 { 50 struct ifnet *ifp = ifp0; 51 struct sockaddr_mpls *smpls; 52 struct sockaddr_mpls sa_mpls; 53 struct shim_hdr *shim; 54 struct rtentry *rt = rt0; 55 struct rt_mpls *rt_mpls; 56 int i, error; 57 u_int8_t ttl; 58 59 if (rt0 == NULL || (dst->sa_family != AF_INET && 60 dst->sa_family != AF_INET6 && dst->sa_family != AF_MPLS)) { 61 if (!ISSET(ifp->if_xflags, IFXF_MPLS)) 62 return (ifp->if_output(ifp, m, dst, rt)); 63 else 64 return (ifp->if_ll_output(ifp, m, dst, rt)); 65 } 66 67 /* need to calculate checksums now if necessary */ 68 mpls_do_cksum(m); 69 70 /* initialize sockaddr_mpls */ 71 bzero(&sa_mpls, sizeof(sa_mpls)); 72 smpls = &sa_mpls; 73 smpls->smpls_family = AF_MPLS; 74 smpls->smpls_len = sizeof(*smpls); 75 76 ttl = mpls_getttl(m, dst->sa_family); 77 78 for (i = 0; i < mpls_inkloop; i++) { 79 rt_mpls = (struct rt_mpls *)rt->rt_llinfo; 80 if (rt_mpls == NULL || (rt->rt_flags & RTF_MPLS) == 0) { 81 /* no MPLS information for this entry */ 82 if (!ISSET(ifp->if_xflags, IFXF_MPLS)) { 83 #ifdef MPLS_DEBUG 84 printf("MPLS_DEBUG: interface not mpls enabled\n"); 85 #endif 86 error = ENETUNREACH; 87 goto bad; 88 } 89 90 return (ifp->if_ll_output(ifp0, m, dst, rt0)); 91 } 92 93 switch (rt_mpls->mpls_operation) { 94 case MPLS_OP_PUSH: 95 m = mpls_shim_push(m, rt_mpls); 96 break; 97 case MPLS_OP_POP: 98 m = mpls_shim_pop(m); 99 break; 100 case MPLS_OP_SWAP: 101 m = mpls_shim_swap(m, rt_mpls); 102 break; 103 default: 104 error = EINVAL; 105 goto bad; 106 } 107 108 if (m == NULL) { 109 error = ENOBUFS; 110 goto bad; 111 } 112 113 /* refetch label */ 114 shim = mtod(m, struct shim_hdr *); 115 /* mark first label with BOS flag */ 116 if (rt0 == rt && dst->sa_family != AF_MPLS) 117 shim->shim_label |= MPLS_BOS_MASK; 118 119 ifp = rt->rt_ifp; 120 if (ifp != NULL) 121 break; 122 123 smpls->smpls_label = shim->shim_label & MPLS_LABEL_MASK; 124 rt = rtalloc1(smplstosa(smpls), RT_REPORT, 0); 125 if (rt == NULL) { 126 /* no entry for this label */ 127 #ifdef MPLS_DEBUG 128 printf("MPLS_DEBUG: label %d not found\n", 129 MPLS_LABEL_GET(shim->shim_label)); 130 #endif 131 error = EHOSTUNREACH; 132 goto bad; 133 } 134 rt->rt_use++; 135 rt->rt_refcnt--; 136 } 137 138 /* write back TTL */ 139 shim->shim_label &= ~MPLS_TTL_MASK; 140 shim->shim_label |= htonl(ttl); 141 142 #ifdef MPLS_DEBUG 143 printf("MPLS: sending on %s outshim %x outlabel %d\n", 144 ifp->if_xname, ntohl(shim->shim_label), 145 MPLS_LABEL_GET(rt_mpls->mpls_label)); 146 #endif 147 148 /* Output iface is not MPLS-enabled */ 149 if (!ISSET(ifp->if_xflags, IFXF_MPLS)) { 150 #ifdef MPLS_DEBUG 151 printf("MPLS_DEBUG: interface not mpls enabled\n"); 152 #endif 153 error = ENETUNREACH; 154 goto bad; 155 } 156 157 /* reset broadcast and multicast flags, this is a P2P tunnel */ 158 m->m_flags &= ~(M_BCAST | M_MCAST); 159 160 smpls->smpls_label = shim->shim_label & MPLS_LABEL_MASK; 161 return (ifp->if_ll_output(ifp, m, smplstosa(smpls), rt)); 162 bad: 163 if (m) 164 m_freem(m); 165 return (error); 166 } 167 168 void 169 mpls_do_cksum(struct mbuf *m) 170 { 171 #ifdef INET 172 struct ip *ip; 173 u_int16_t hlen; 174 175 in_proto_cksum_out(m, NULL); 176 177 if (m->m_pkthdr.csum_flags & M_IPV4_CSUM_OUT) { 178 ip = mtod(m, struct ip *); 179 hlen = ip->ip_hl << 2; 180 ip->ip_sum = in_cksum(m, hlen); 181 m->m_pkthdr.csum_flags &= ~M_IPV4_CSUM_OUT; 182 } 183 #endif 184 } 185 186 u_int8_t 187 mpls_getttl(struct mbuf *m, sa_family_t af) 188 { 189 struct shim_hdr *shim; 190 struct ip *ip; 191 #ifdef INET6 192 struct ip6_hdr *ip6hdr; 193 #endif 194 u_int8_t ttl = mpls_defttl; 195 196 /* If the AF is MPLS then inherit the TTL from the present label. */ 197 if (af == AF_MPLS) { 198 shim = mtod(m, struct shim_hdr *); 199 ttl = ntohl(shim->shim_label & MPLS_TTL_MASK); 200 return (ttl); 201 } 202 /* Else extract TTL from the encapsualted packet. */ 203 switch (*mtod(m, u_char *) >> 4) { 204 case IPVERSION: 205 if (!mpls_mapttl_ip) 206 break; 207 if (m->m_len < sizeof(*ip)) 208 break; /* impossible */ 209 ip = mtod(m, struct ip *); 210 ttl = ip->ip_ttl; 211 break; 212 #ifdef INET6 213 case IPV6_VERSION >> 4: 214 if (!mpls_mapttl_ip6) 215 break; 216 if (m->m_len < sizeof(struct ip6_hdr)) 217 break; /* impossible */ 218 ip6hdr = mtod(m, struct ip6_hdr *); 219 ttl = ip6hdr->ip6_hlim; 220 break; 221 #endif 222 default: 223 break; 224 } 225 return (ttl); 226 } 227