1 /* $OpenBSD: mpls_output.c,v 1.28 2019/09/03 10:39:08 jsg 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/if_var.h> 27 #include <net/route.h> 28 29 #include <netmpls/mpls.h> 30 31 #include <netinet/in.h> 32 #include <netinet/ip.h> 33 34 #ifdef INET6 35 #include <netinet/ip6.h> 36 #endif 37 38 #ifdef MPLS_DEBUG 39 #define MPLS_LABEL_GET(l) ((ntohl((l) & MPLS_LABEL_MASK)) >> MPLS_LABEL_OFFSET) 40 #endif 41 42 void mpls_do_cksum(struct mbuf *); 43 u_int8_t mpls_getttl(struct mbuf *, sa_family_t); 44 45 int 46 mpls_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst, 47 struct rtentry *rt) 48 { 49 struct sockaddr_mpls *smpls; 50 struct sockaddr_mpls sa_mpls; 51 struct shim_hdr *shim; 52 struct rt_mpls *rt_mpls; 53 int error; 54 u_int8_t ttl; 55 56 if (rt == NULL || (dst->sa_family != AF_INET && 57 dst->sa_family != AF_INET6 && dst->sa_family != AF_MPLS)) { 58 if (!ISSET(ifp->if_xflags, IFXF_MPLS)) 59 return (ifp->if_output(ifp, m, dst, rt)); 60 else 61 return (ifp->if_ll_output(ifp, m, dst, rt)); 62 } 63 64 /* need to calculate checksums now if necessary */ 65 mpls_do_cksum(m); 66 67 /* initialize sockaddr_mpls */ 68 bzero(&sa_mpls, sizeof(sa_mpls)); 69 smpls = &sa_mpls; 70 smpls->smpls_family = AF_MPLS; 71 smpls->smpls_len = sizeof(*smpls); 72 73 ttl = mpls_getttl(m, dst->sa_family); 74 75 rt_mpls = (struct rt_mpls *)rt->rt_llinfo; 76 if (rt_mpls == NULL || (rt->rt_flags & RTF_MPLS) == 0) { 77 /* no MPLS information for this entry */ 78 if (!ISSET(ifp->if_xflags, IFXF_MPLS)) { 79 #ifdef MPLS_DEBUG 80 printf("MPLS_DEBUG: interface not mpls enabled\n"); 81 #endif 82 error = ENETUNREACH; 83 goto bad; 84 } 85 86 return (ifp->if_ll_output(ifp, m, dst, rt)); 87 } 88 89 /* to be honest here only the push operation makes sense */ 90 switch (rt_mpls->mpls_operation) { 91 case MPLS_OP_PUSH: 92 m = mpls_shim_push(m, rt_mpls); 93 break; 94 case MPLS_OP_POP: 95 m = mpls_shim_pop(m); 96 break; 97 case MPLS_OP_SWAP: 98 m = mpls_shim_swap(m, rt_mpls); 99 break; 100 default: 101 error = EINVAL; 102 goto bad; 103 } 104 105 if (m == NULL) { 106 error = ENOBUFS; 107 goto bad; 108 } 109 110 /* refetch label */ 111 shim = mtod(m, struct shim_hdr *); 112 /* mark first label with BOS flag */ 113 if (dst->sa_family != AF_MPLS) 114 shim->shim_label |= MPLS_BOS_MASK; 115 116 /* write back TTL */ 117 shim->shim_label &= ~MPLS_TTL_MASK; 118 shim->shim_label |= htonl(ttl); 119 120 #ifdef MPLS_DEBUG 121 printf("MPLS: sending on %s outshim %x outlabel %d\n", 122 ifp->if_xname, ntohl(shim->shim_label), 123 MPLS_LABEL_GET(rt_mpls->mpls_label)); 124 #endif 125 126 /* Output iface is not MPLS-enabled */ 127 if (!ISSET(ifp->if_xflags, IFXF_MPLS)) { 128 #ifdef MPLS_DEBUG 129 printf("MPLS_DEBUG: interface not mpls enabled\n"); 130 #endif 131 error = ENETUNREACH; 132 goto bad; 133 } 134 135 /* reset broadcast and multicast flags, this is a P2P tunnel */ 136 m->m_flags &= ~(M_BCAST | M_MCAST); 137 138 smpls->smpls_label = shim->shim_label & MPLS_LABEL_MASK; 139 error = ifp->if_ll_output(ifp, m, smplstosa(smpls), rt); 140 return (error); 141 bad: 142 m_freem(m); 143 return (error); 144 } 145 146 void 147 mpls_do_cksum(struct mbuf *m) 148 { 149 struct ip *ip; 150 u_int16_t hlen; 151 152 in_proto_cksum_out(m, NULL); 153 154 if (m->m_pkthdr.csum_flags & M_IPV4_CSUM_OUT) { 155 ip = mtod(m, struct ip *); 156 hlen = ip->ip_hl << 2; 157 ip->ip_sum = in_cksum(m, hlen); 158 m->m_pkthdr.csum_flags &= ~M_IPV4_CSUM_OUT; 159 } 160 } 161 162 u_int8_t 163 mpls_getttl(struct mbuf *m, sa_family_t af) 164 { 165 struct mbuf *n; 166 int loc, off; 167 u_int8_t ttl = mpls_defttl; 168 169 /* If the AF is MPLS then inherit the TTL from the present label. */ 170 if (af == AF_MPLS) 171 loc = 3; 172 else { 173 switch (*mtod(m, uint8_t *) >> 4) { 174 case 4: 175 if (!mpls_mapttl_ip) 176 return (ttl); 177 178 loc = offsetof(struct ip, ip_ttl); 179 break; 180 #ifdef INET6 181 case 6: 182 if (!mpls_mapttl_ip6) 183 return (ttl); 184 185 loc = offsetof(struct ip6_hdr, ip6_hlim); 186 break; 187 #endif 188 default: 189 return (ttl); 190 } 191 } 192 193 n = m_getptr(m, loc, &off); 194 if (n == NULL) 195 return (ttl); 196 197 ttl = *(mtod(n, uint8_t *) + off); 198 199 return (ttl); 200 } 201