1 /* $OpenBSD: mpls_output.c,v 1.16 2013/04/24 10:20:15 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/in_systm.h> 33 #include <netinet/ip.h> 34 #endif 35 36 #ifdef INET6 37 #include <netinet/ip6.h> 38 #endif 39 40 #ifdef MPLS_DEBUG 41 #define MPLS_LABEL_GET(l) ((ntohl((l) & MPLS_LABEL_MASK)) >> MPLS_LABEL_OFFSET) 42 #endif 43 44 void mpls_do_cksum(struct mbuf *); 45 u_int8_t mpls_getttl(struct mbuf *, sa_family_t); 46 47 int 48 mpls_output(struct ifnet *ifp0, struct mbuf *m, struct sockaddr *dst, 49 struct rtentry *rt0) 50 { 51 struct ifnet *ifp = ifp0; 52 struct sockaddr_mpls *smpls; 53 struct sockaddr_mpls sa_mpls; 54 struct shim_hdr *shim; 55 struct rtentry *rt = rt0; 56 struct rt_mpls *rt_mpls; 57 int i, error; 58 u_int8_t ttl; 59 60 if (rt0 == NULL || (dst->sa_family != AF_INET && 61 dst->sa_family != AF_INET6 && dst->sa_family != AF_MPLS)) { 62 if (!ISSET(ifp->if_xflags, IFXF_MPLS)) 63 return (ifp->if_output(ifp, m, dst, rt)); 64 else 65 return (ifp->if_ll_output(ifp, m, dst, rt)); 66 } 67 68 /* need to calculate checksums now if necessary */ 69 mpls_do_cksum(m); 70 71 /* initialize sockaddr_mpls */ 72 bzero(&sa_mpls, sizeof(sa_mpls)); 73 smpls = &sa_mpls; 74 smpls->smpls_family = AF_MPLS; 75 smpls->smpls_len = sizeof(*smpls); 76 77 ttl = mpls_getttl(m, dst->sa_family); 78 79 for (i = 0; i < mpls_inkloop; i++) { 80 rt_mpls = (struct rt_mpls *)rt->rt_llinfo; 81 if (rt_mpls == NULL || (rt->rt_flags & RTF_MPLS) == 0) { 82 /* no MPLS information for this entry */ 83 if (!ISSET(ifp->if_xflags, IFXF_MPLS)) { 84 #ifdef MPLS_DEBUG 85 printf("MPLS_DEBUG: interface not mpls enabled\n"); 86 #endif 87 error = ENETUNREACH; 88 goto bad; 89 } 90 91 return (ifp->if_ll_output(ifp0, m, dst, rt0)); 92 } 93 94 switch (rt_mpls->mpls_operation) { 95 case MPLS_OP_PUSH: 96 m = mpls_shim_push(m, rt_mpls); 97 break; 98 case MPLS_OP_POP: 99 m = mpls_shim_pop(m); 100 break; 101 case MPLS_OP_SWAP: 102 m = mpls_shim_swap(m, rt_mpls); 103 break; 104 default: 105 error = EINVAL; 106 goto bad; 107 } 108 109 if (m == NULL) { 110 error = ENOBUFS; 111 goto bad; 112 } 113 114 /* refetch label */ 115 shim = mtod(m, struct shim_hdr *); 116 /* mark first label with BOS flag */ 117 if (rt0 == rt && dst->sa_family != AF_MPLS) 118 shim->shim_label |= MPLS_BOS_MASK; 119 120 ifp = rt->rt_ifp; 121 if (ifp != NULL) 122 break; 123 124 smpls->smpls_label = shim->shim_label & MPLS_LABEL_MASK; 125 rt = rtalloc1(smplstosa(smpls), RT_REPORT, 0); 126 if (rt == NULL) { 127 /* no entry for this label */ 128 #ifdef MPLS_DEBUG 129 printf("MPLS_DEBUG: label %d not found\n", 130 MPLS_LABEL_GET(shim->shim_label)); 131 #endif 132 error = EHOSTUNREACH; 133 goto bad; 134 } 135 rt->rt_use++; 136 rt->rt_refcnt--; 137 } 138 139 /* write back TTL */ 140 shim->shim_label &= ~MPLS_TTL_MASK; 141 shim->shim_label |= htonl(ttl); 142 143 #ifdef MPLS_DEBUG 144 printf("MPLS: sending on %s outshim %x outlabel %d\n", 145 ifp->if_xname, ntohl(shim->shim_label), 146 MPLS_LABEL_GET(rt_mpls->mpls_label)); 147 #endif 148 149 /* Output iface is not MPLS-enabled */ 150 if (!ISSET(ifp->if_xflags, IFXF_MPLS)) { 151 #ifdef MPLS_DEBUG 152 printf("MPLS_DEBUG: interface not mpls enabled\n"); 153 #endif 154 error = ENETUNREACH; 155 goto bad; 156 } 157 158 /* reset broadcast and multicast flags, this is a P2P tunnel */ 159 m->m_flags &= ~(M_BCAST | M_MCAST); 160 161 smpls->smpls_label = shim->shim_label & MPLS_LABEL_MASK; 162 return (ifp->if_ll_output(ifp, m, smplstosa(smpls), rt)); 163 bad: 164 if (m) 165 m_freem(m); 166 return (error); 167 } 168 169 void 170 mpls_do_cksum(struct mbuf *m) 171 { 172 #ifdef INET 173 struct ip *ip; 174 u_int16_t hlen; 175 176 in_proto_cksum_out(m, NULL); 177 178 if (m->m_pkthdr.csum_flags & M_IPV4_CSUM_OUT) { 179 ip = mtod(m, struct ip *); 180 hlen = ip->ip_hl << 2; 181 ip->ip_sum = in_cksum(m, hlen); 182 m->m_pkthdr.csum_flags &= ~M_IPV4_CSUM_OUT; 183 } 184 #endif 185 } 186 187 u_int8_t 188 mpls_getttl(struct mbuf *m, sa_family_t af) 189 { 190 struct shim_hdr *shim; 191 struct ip *ip; 192 #ifdef INET6 193 struct ip6_hdr *ip6hdr; 194 #endif 195 u_int8_t ttl = mpls_defttl; 196 197 /* If the AF is MPLS then inherit the TTL from the present label. */ 198 if (af == AF_MPLS) { 199 shim = mtod(m, struct shim_hdr *); 200 ttl = ntohl(shim->shim_label & MPLS_TTL_MASK); 201 return (ttl); 202 } 203 /* Else extract TTL from the encapsualted packet. */ 204 switch (*mtod(m, u_char *) >> 4) { 205 case IPVERSION: 206 if (!mpls_mapttl_ip) 207 break; 208 if (m->m_len < sizeof(*ip)) 209 break; /* impossible */ 210 ip = mtod(m, struct ip *); 211 ttl = ip->ip_ttl; 212 break; 213 #ifdef INET6 214 case IPV6_VERSION >> 4: 215 if (!mpls_mapttl_ip6) 216 break; 217 if (m->m_len < sizeof(struct ip6_hdr)) 218 break; /* impossible */ 219 ip6hdr = mtod(m, struct ip6_hdr *); 220 ttl = ip6hdr->ip6_hlim; 221 break; 222 #endif 223 default: 224 break; 225 } 226 return (ttl); 227 } 228