1 /* 2 * xfrm4_policy.c 3 * 4 * Changes: 5 * Kazunori MIYAZAWA @USAGI 6 * YOSHIFUJI Hideaki @USAGI 7 * Split up af-specific portion 8 * 9 */ 10 11 #include <linux/compiler.h> 12 #include <linux/inetdevice.h> 13 #include <net/xfrm.h> 14 #include <net/ip.h> 15 16 static struct dst_ops xfrm4_dst_ops; 17 static struct xfrm_policy_afinfo xfrm4_policy_afinfo; 18 19 static int xfrm4_dst_lookup(struct xfrm_dst **dst, struct flowi *fl) 20 { 21 return __ip_route_output_key((struct rtable**)dst, fl); 22 } 23 24 static int xfrm4_get_saddr(xfrm_address_t *saddr, xfrm_address_t *daddr) 25 { 26 struct rtable *rt; 27 struct flowi fl_tunnel = { 28 .nl_u = { 29 .ip4_u = { 30 .daddr = daddr->a4, 31 }, 32 }, 33 }; 34 35 if (!xfrm4_dst_lookup((struct xfrm_dst **)&rt, &fl_tunnel)) { 36 saddr->a4 = rt->rt_src; 37 dst_release(&rt->u.dst); 38 return 0; 39 } 40 return -EHOSTUNREACH; 41 } 42 43 static struct dst_entry * 44 __xfrm4_find_bundle(struct flowi *fl, struct xfrm_policy *policy) 45 { 46 struct dst_entry *dst; 47 48 read_lock_bh(&policy->lock); 49 for (dst = policy->bundles; dst; dst = dst->next) { 50 struct xfrm_dst *xdst = (struct xfrm_dst*)dst; 51 if (xdst->u.rt.fl.oif == fl->oif && /*XXX*/ 52 xdst->u.rt.fl.fl4_dst == fl->fl4_dst && 53 xdst->u.rt.fl.fl4_src == fl->fl4_src && 54 xdst->u.rt.fl.fl4_tos == fl->fl4_tos && 55 xfrm_bundle_ok(policy, xdst, fl, AF_INET, 0)) { 56 dst_clone(dst); 57 break; 58 } 59 } 60 read_unlock_bh(&policy->lock); 61 return dst; 62 } 63 64 /* Allocate chain of dst_entry's, attach known xfrm's, calculate 65 * all the metrics... Shortly, bundle a bundle. 66 */ 67 68 static int 69 __xfrm4_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx, 70 struct flowi *fl, struct dst_entry **dst_p) 71 { 72 struct dst_entry *dst, *dst_prev; 73 struct rtable *rt0 = (struct rtable*)(*dst_p); 74 struct rtable *rt = rt0; 75 struct flowi fl_tunnel = { 76 .nl_u = { 77 .ip4_u = { 78 .saddr = fl->fl4_src, 79 .daddr = fl->fl4_dst, 80 .tos = fl->fl4_tos 81 } 82 } 83 }; 84 int i; 85 int err; 86 int header_len = 0; 87 int trailer_len = 0; 88 89 dst = dst_prev = NULL; 90 dst_hold(&rt->u.dst); 91 92 for (i = 0; i < nx; i++) { 93 struct dst_entry *dst1 = dst_alloc(&xfrm4_dst_ops); 94 struct xfrm_dst *xdst; 95 96 if (unlikely(dst1 == NULL)) { 97 err = -ENOBUFS; 98 dst_release(&rt->u.dst); 99 goto error; 100 } 101 102 if (!dst) 103 dst = dst1; 104 else { 105 dst_prev->child = dst1; 106 dst1->flags |= DST_NOHASH; 107 dst_clone(dst1); 108 } 109 110 xdst = (struct xfrm_dst *)dst1; 111 xdst->route = &rt->u.dst; 112 xdst->genid = xfrm[i]->genid; 113 114 dst1->next = dst_prev; 115 dst_prev = dst1; 116 117 header_len += xfrm[i]->props.header_len; 118 trailer_len += xfrm[i]->props.trailer_len; 119 120 if (xfrm[i]->props.mode != XFRM_MODE_TRANSPORT) { 121 unsigned short encap_family = xfrm[i]->props.family; 122 switch (encap_family) { 123 case AF_INET: 124 fl_tunnel.fl4_dst = xfrm[i]->id.daddr.a4; 125 fl_tunnel.fl4_src = xfrm[i]->props.saddr.a4; 126 break; 127 #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) 128 case AF_INET6: 129 ipv6_addr_copy(&fl_tunnel.fl6_dst, (struct in6_addr*)&xfrm[i]->id.daddr.a6); 130 ipv6_addr_copy(&fl_tunnel.fl6_src, (struct in6_addr*)&xfrm[i]->props.saddr.a6); 131 break; 132 #endif 133 default: 134 BUG_ON(1); 135 } 136 err = xfrm_dst_lookup((struct xfrm_dst **)&rt, 137 &fl_tunnel, encap_family); 138 if (err) 139 goto error; 140 } else 141 dst_hold(&rt->u.dst); 142 } 143 144 dst_prev->child = &rt->u.dst; 145 dst->path = &rt->u.dst; 146 147 *dst_p = dst; 148 dst = dst_prev; 149 150 dst_prev = *dst_p; 151 i = 0; 152 for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) { 153 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev; 154 x->u.rt.fl = *fl; 155 156 dst_prev->xfrm = xfrm[i++]; 157 dst_prev->dev = rt->u.dst.dev; 158 if (rt->u.dst.dev) 159 dev_hold(rt->u.dst.dev); 160 dst_prev->obsolete = -1; 161 dst_prev->flags |= DST_HOST; 162 dst_prev->lastuse = jiffies; 163 dst_prev->header_len = header_len; 164 dst_prev->nfheader_len = 0; 165 dst_prev->trailer_len = trailer_len; 166 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics)); 167 168 /* Copy neighbout for reachability confirmation */ 169 dst_prev->neighbour = neigh_clone(rt->u.dst.neighbour); 170 dst_prev->input = rt->u.dst.input; 171 dst_prev->output = dst_prev->xfrm->outer_mode->afinfo->output; 172 if (rt0->peer) 173 atomic_inc(&rt0->peer->refcnt); 174 x->u.rt.peer = rt0->peer; 175 /* Sheit... I remember I did this right. Apparently, 176 * it was magically lost, so this code needs audit */ 177 x->u.rt.rt_flags = rt0->rt_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL); 178 x->u.rt.rt_type = rt0->rt_type; 179 x->u.rt.rt_src = rt0->rt_src; 180 x->u.rt.rt_dst = rt0->rt_dst; 181 x->u.rt.rt_gateway = rt0->rt_gateway; 182 x->u.rt.rt_spec_dst = rt0->rt_spec_dst; 183 x->u.rt.idev = rt0->idev; 184 in_dev_hold(rt0->idev); 185 header_len -= x->u.dst.xfrm->props.header_len; 186 trailer_len -= x->u.dst.xfrm->props.trailer_len; 187 } 188 189 xfrm_init_pmtu(dst); 190 return 0; 191 192 error: 193 if (dst) 194 dst_free(dst); 195 return err; 196 } 197 198 static void 199 _decode_session4(struct sk_buff *skb, struct flowi *fl) 200 { 201 struct iphdr *iph = ip_hdr(skb); 202 u8 *xprth = skb_network_header(skb) + iph->ihl * 4; 203 204 memset(fl, 0, sizeof(struct flowi)); 205 if (!(iph->frag_off & htons(IP_MF | IP_OFFSET))) { 206 switch (iph->protocol) { 207 case IPPROTO_UDP: 208 case IPPROTO_UDPLITE: 209 case IPPROTO_TCP: 210 case IPPROTO_SCTP: 211 case IPPROTO_DCCP: 212 if (pskb_may_pull(skb, xprth + 4 - skb->data)) { 213 __be16 *ports = (__be16 *)xprth; 214 215 fl->fl_ip_sport = ports[0]; 216 fl->fl_ip_dport = ports[1]; 217 } 218 break; 219 220 case IPPROTO_ICMP: 221 if (pskb_may_pull(skb, xprth + 2 - skb->data)) { 222 u8 *icmp = xprth; 223 224 fl->fl_icmp_type = icmp[0]; 225 fl->fl_icmp_code = icmp[1]; 226 } 227 break; 228 229 case IPPROTO_ESP: 230 if (pskb_may_pull(skb, xprth + 4 - skb->data)) { 231 __be32 *ehdr = (__be32 *)xprth; 232 233 fl->fl_ipsec_spi = ehdr[0]; 234 } 235 break; 236 237 case IPPROTO_AH: 238 if (pskb_may_pull(skb, xprth + 8 - skb->data)) { 239 __be32 *ah_hdr = (__be32*)xprth; 240 241 fl->fl_ipsec_spi = ah_hdr[1]; 242 } 243 break; 244 245 case IPPROTO_COMP: 246 if (pskb_may_pull(skb, xprth + 4 - skb->data)) { 247 __be16 *ipcomp_hdr = (__be16 *)xprth; 248 249 fl->fl_ipsec_spi = htonl(ntohs(ipcomp_hdr[1])); 250 } 251 break; 252 default: 253 fl->fl_ipsec_spi = 0; 254 break; 255 } 256 } 257 fl->proto = iph->protocol; 258 fl->fl4_dst = iph->daddr; 259 fl->fl4_src = iph->saddr; 260 fl->fl4_tos = iph->tos; 261 } 262 263 static inline int xfrm4_garbage_collect(void) 264 { 265 xfrm4_policy_afinfo.garbage_collect(); 266 return (atomic_read(&xfrm4_dst_ops.entries) > xfrm4_dst_ops.gc_thresh*2); 267 } 268 269 static void xfrm4_update_pmtu(struct dst_entry *dst, u32 mtu) 270 { 271 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 272 struct dst_entry *path = xdst->route; 273 274 path->ops->update_pmtu(path, mtu); 275 } 276 277 static void xfrm4_dst_destroy(struct dst_entry *dst) 278 { 279 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 280 281 if (likely(xdst->u.rt.idev)) 282 in_dev_put(xdst->u.rt.idev); 283 if (likely(xdst->u.rt.peer)) 284 inet_putpeer(xdst->u.rt.peer); 285 xfrm_dst_destroy(xdst); 286 } 287 288 static void xfrm4_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 289 int unregister) 290 { 291 struct xfrm_dst *xdst; 292 293 if (!unregister) 294 return; 295 296 xdst = (struct xfrm_dst *)dst; 297 if (xdst->u.rt.idev->dev == dev) { 298 struct in_device *loopback_idev = in_dev_get(init_net.loopback_dev); 299 BUG_ON(!loopback_idev); 300 301 do { 302 in_dev_put(xdst->u.rt.idev); 303 xdst->u.rt.idev = loopback_idev; 304 in_dev_hold(loopback_idev); 305 xdst = (struct xfrm_dst *)xdst->u.dst.child; 306 } while (xdst->u.dst.xfrm); 307 308 __in_dev_put(loopback_idev); 309 } 310 311 xfrm_dst_ifdown(dst, dev); 312 } 313 314 static struct dst_ops xfrm4_dst_ops = { 315 .family = AF_INET, 316 .protocol = __constant_htons(ETH_P_IP), 317 .gc = xfrm4_garbage_collect, 318 .update_pmtu = xfrm4_update_pmtu, 319 .destroy = xfrm4_dst_destroy, 320 .ifdown = xfrm4_dst_ifdown, 321 .gc_thresh = 1024, 322 .entry_size = sizeof(struct xfrm_dst), 323 }; 324 325 static struct xfrm_policy_afinfo xfrm4_policy_afinfo = { 326 .family = AF_INET, 327 .dst_ops = &xfrm4_dst_ops, 328 .dst_lookup = xfrm4_dst_lookup, 329 .get_saddr = xfrm4_get_saddr, 330 .find_bundle = __xfrm4_find_bundle, 331 .bundle_create = __xfrm4_bundle_create, 332 .decode_session = _decode_session4, 333 }; 334 335 static void __init xfrm4_policy_init(void) 336 { 337 xfrm_policy_register_afinfo(&xfrm4_policy_afinfo); 338 } 339 340 static void __exit xfrm4_policy_fini(void) 341 { 342 xfrm_policy_unregister_afinfo(&xfrm4_policy_afinfo); 343 } 344 345 void __init xfrm4_init(void) 346 { 347 xfrm4_state_init(); 348 xfrm4_policy_init(); 349 } 350 351