1 /* 2 * xfrm6_policy.c: based on xfrm4_policy.c 3 * 4 * Authors: 5 * Mitsuru KANDA @USAGI 6 * Kazunori MIYAZAWA @USAGI 7 * Kunihiro Ishiguro <kunihiro@ipinfusion.com> 8 * IPv6 support 9 * YOSHIFUJI Hideaki 10 * Split up af-specific portion 11 * 12 */ 13 14 #include <linux/err.h> 15 #include <linux/kernel.h> 16 #include <linux/netdevice.h> 17 #include <net/addrconf.h> 18 #include <net/dst.h> 19 #include <net/xfrm.h> 20 #include <net/ip.h> 21 #include <net/ipv6.h> 22 #include <net/ip6_route.h> 23 #if IS_ENABLED(CONFIG_IPV6_MIP6) 24 #include <net/mip6.h> 25 #endif 26 27 static struct xfrm_policy_afinfo xfrm6_policy_afinfo; 28 29 static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos, 30 const xfrm_address_t *saddr, 31 const xfrm_address_t *daddr) 32 { 33 struct flowi6 fl6; 34 struct dst_entry *dst; 35 int err; 36 37 memset(&fl6, 0, sizeof(fl6)); 38 memcpy(&fl6.daddr, daddr, sizeof(fl6.daddr)); 39 if (saddr) 40 memcpy(&fl6.saddr, saddr, sizeof(fl6.saddr)); 41 42 dst = ip6_route_output(net, NULL, &fl6); 43 44 err = dst->error; 45 if (dst->error) { 46 dst_release(dst); 47 dst = ERR_PTR(err); 48 } 49 50 return dst; 51 } 52 53 static int xfrm6_get_saddr(struct net *net, 54 xfrm_address_t *saddr, xfrm_address_t *daddr) 55 { 56 struct dst_entry *dst; 57 struct net_device *dev; 58 59 dst = xfrm6_dst_lookup(net, 0, NULL, daddr); 60 if (IS_ERR(dst)) 61 return -EHOSTUNREACH; 62 63 dev = ip6_dst_idev(dst)->dev; 64 ipv6_dev_get_saddr(dev_net(dev), dev, 65 (struct in6_addr *)&daddr->a6, 0, 66 (struct in6_addr *)&saddr->a6); 67 dst_release(dst); 68 return 0; 69 } 70 71 static int xfrm6_get_tos(const struct flowi *fl) 72 { 73 return 0; 74 } 75 76 static void xfrm6_init_dst(struct net *net, struct xfrm_dst *xdst) 77 { 78 struct rt6_info *rt = (struct rt6_info *)xdst; 79 80 rt6_init_peer(rt, net->ipv6.peers); 81 } 82 83 static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst, 84 int nfheader_len) 85 { 86 if (dst->ops->family == AF_INET6) { 87 struct rt6_info *rt = (struct rt6_info *)dst; 88 if (rt->rt6i_node) 89 path->path_cookie = rt->rt6i_node->fn_sernum; 90 } 91 92 path->u.rt6.rt6i_nfheader_len = nfheader_len; 93 94 return 0; 95 } 96 97 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev, 98 const struct flowi *fl) 99 { 100 struct rt6_info *rt = (struct rt6_info *)xdst->route; 101 102 xdst->u.dst.dev = dev; 103 dev_hold(dev); 104 105 xdst->u.rt6.rt6i_idev = in6_dev_get(dev); 106 if (!xdst->u.rt6.rt6i_idev) { 107 dev_put(dev); 108 return -ENODEV; 109 } 110 111 rt6_transfer_peer(&xdst->u.rt6, rt); 112 113 /* Sheit... I remember I did this right. Apparently, 114 * it was magically lost, so this code needs audit */ 115 xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST | 116 RTF_LOCAL); 117 xdst->u.rt6.rt6i_metric = rt->rt6i_metric; 118 xdst->u.rt6.rt6i_node = rt->rt6i_node; 119 if (rt->rt6i_node) 120 xdst->route_cookie = rt->rt6i_node->fn_sernum; 121 xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway; 122 xdst->u.rt6.rt6i_dst = rt->rt6i_dst; 123 xdst->u.rt6.rt6i_src = rt->rt6i_src; 124 125 return 0; 126 } 127 128 static inline void 129 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse) 130 { 131 struct flowi6 *fl6 = &fl->u.ip6; 132 int onlyproto = 0; 133 const struct ipv6hdr *hdr = ipv6_hdr(skb); 134 u16 offset = sizeof(*hdr); 135 struct ipv6_opt_hdr *exthdr; 136 const unsigned char *nh = skb_network_header(skb); 137 u16 nhoff = IP6CB(skb)->nhoff; 138 int oif = 0; 139 u8 nexthdr; 140 141 if (!nhoff) 142 nhoff = offsetof(struct ipv6hdr, nexthdr); 143 144 nexthdr = nh[nhoff]; 145 146 if (skb_dst(skb)) 147 oif = skb_dst(skb)->dev->ifindex; 148 149 memset(fl6, 0, sizeof(struct flowi6)); 150 fl6->flowi6_mark = skb->mark; 151 fl6->flowi6_oif = reverse ? skb->skb_iif : oif; 152 153 fl6->daddr = reverse ? hdr->saddr : hdr->daddr; 154 fl6->saddr = reverse ? hdr->daddr : hdr->saddr; 155 156 while (nh + offset + 1 < skb->data || 157 pskb_may_pull(skb, nh + offset + 1 - skb->data)) { 158 nh = skb_network_header(skb); 159 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 160 161 switch (nexthdr) { 162 case NEXTHDR_FRAGMENT: 163 onlyproto = 1; 164 case NEXTHDR_ROUTING: 165 case NEXTHDR_HOP: 166 case NEXTHDR_DEST: 167 offset += ipv6_optlen(exthdr); 168 nexthdr = exthdr->nexthdr; 169 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 170 break; 171 172 case IPPROTO_UDP: 173 case IPPROTO_UDPLITE: 174 case IPPROTO_TCP: 175 case IPPROTO_SCTP: 176 case IPPROTO_DCCP: 177 if (!onlyproto && (nh + offset + 4 < skb->data || 178 pskb_may_pull(skb, nh + offset + 4 - skb->data))) { 179 __be16 *ports; 180 181 nh = skb_network_header(skb); 182 ports = (__be16 *)(nh + offset); 183 fl6->fl6_sport = ports[!!reverse]; 184 fl6->fl6_dport = ports[!reverse]; 185 } 186 fl6->flowi6_proto = nexthdr; 187 return; 188 189 case IPPROTO_ICMPV6: 190 if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) { 191 u8 *icmp; 192 193 nh = skb_network_header(skb); 194 icmp = (u8 *)(nh + offset); 195 fl6->fl6_icmp_type = icmp[0]; 196 fl6->fl6_icmp_code = icmp[1]; 197 } 198 fl6->flowi6_proto = nexthdr; 199 return; 200 201 #if IS_ENABLED(CONFIG_IPV6_MIP6) 202 case IPPROTO_MH: 203 offset += ipv6_optlen(exthdr); 204 if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) { 205 struct ip6_mh *mh; 206 207 nh = skb_network_header(skb); 208 mh = (struct ip6_mh *)(nh + offset); 209 fl6->fl6_mh_type = mh->ip6mh_type; 210 } 211 fl6->flowi6_proto = nexthdr; 212 return; 213 #endif 214 215 /* XXX Why are there these headers? */ 216 case IPPROTO_AH: 217 case IPPROTO_ESP: 218 case IPPROTO_COMP: 219 default: 220 fl6->fl6_ipsec_spi = 0; 221 fl6->flowi6_proto = nexthdr; 222 return; 223 } 224 } 225 } 226 227 static inline int xfrm6_garbage_collect(struct dst_ops *ops) 228 { 229 struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops); 230 231 xfrm6_policy_afinfo.garbage_collect(net); 232 return dst_entries_get_fast(ops) > ops->gc_thresh * 2; 233 } 234 235 static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk, 236 struct sk_buff *skb, u32 mtu) 237 { 238 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 239 struct dst_entry *path = xdst->route; 240 241 path->ops->update_pmtu(path, sk, skb, mtu); 242 } 243 244 static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk, 245 struct sk_buff *skb) 246 { 247 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 248 struct dst_entry *path = xdst->route; 249 250 path->ops->redirect(path, sk, skb); 251 } 252 253 static void xfrm6_dst_destroy(struct dst_entry *dst) 254 { 255 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 256 257 if (likely(xdst->u.rt6.rt6i_idev)) 258 in6_dev_put(xdst->u.rt6.rt6i_idev); 259 dst_destroy_metrics_generic(dst); 260 if (rt6_has_peer(&xdst->u.rt6)) { 261 struct inet_peer *peer = rt6_peer_ptr(&xdst->u.rt6); 262 inet_putpeer(peer); 263 } 264 xfrm_dst_destroy(xdst); 265 } 266 267 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 268 int unregister) 269 { 270 struct xfrm_dst *xdst; 271 272 if (!unregister) 273 return; 274 275 xdst = (struct xfrm_dst *)dst; 276 if (xdst->u.rt6.rt6i_idev->dev == dev) { 277 struct inet6_dev *loopback_idev = 278 in6_dev_get(dev_net(dev)->loopback_dev); 279 BUG_ON(!loopback_idev); 280 281 do { 282 in6_dev_put(xdst->u.rt6.rt6i_idev); 283 xdst->u.rt6.rt6i_idev = loopback_idev; 284 in6_dev_hold(loopback_idev); 285 xdst = (struct xfrm_dst *)xdst->u.dst.child; 286 } while (xdst->u.dst.xfrm); 287 288 __in6_dev_put(loopback_idev); 289 } 290 291 xfrm_dst_ifdown(dst, dev); 292 } 293 294 static struct dst_ops xfrm6_dst_ops = { 295 .family = AF_INET6, 296 .protocol = cpu_to_be16(ETH_P_IPV6), 297 .gc = xfrm6_garbage_collect, 298 .update_pmtu = xfrm6_update_pmtu, 299 .redirect = xfrm6_redirect, 300 .cow_metrics = dst_cow_metrics_generic, 301 .destroy = xfrm6_dst_destroy, 302 .ifdown = xfrm6_dst_ifdown, 303 .local_out = __ip6_local_out, 304 .gc_thresh = 32768, 305 }; 306 307 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = { 308 .family = AF_INET6, 309 .dst_ops = &xfrm6_dst_ops, 310 .dst_lookup = xfrm6_dst_lookup, 311 .get_saddr = xfrm6_get_saddr, 312 .decode_session = _decode_session6, 313 .get_tos = xfrm6_get_tos, 314 .init_dst = xfrm6_init_dst, 315 .init_path = xfrm6_init_path, 316 .fill_dst = xfrm6_fill_dst, 317 .blackhole_route = ip6_blackhole_route, 318 }; 319 320 static int __init xfrm6_policy_init(void) 321 { 322 return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo); 323 } 324 325 static void xfrm6_policy_fini(void) 326 { 327 xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo); 328 } 329 330 #ifdef CONFIG_SYSCTL 331 static struct ctl_table xfrm6_policy_table[] = { 332 { 333 .procname = "xfrm6_gc_thresh", 334 .data = &init_net.xfrm.xfrm6_dst_ops.gc_thresh, 335 .maxlen = sizeof(int), 336 .mode = 0644, 337 .proc_handler = proc_dointvec, 338 }, 339 { } 340 }; 341 342 static int __net_init xfrm6_net_init(struct net *net) 343 { 344 struct ctl_table *table; 345 struct ctl_table_header *hdr; 346 347 table = xfrm6_policy_table; 348 if (!net_eq(net, &init_net)) { 349 table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL); 350 if (!table) 351 goto err_alloc; 352 353 table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh; 354 } 355 356 hdr = register_net_sysctl(net, "net/ipv6", table); 357 if (!hdr) 358 goto err_reg; 359 360 net->ipv6.sysctl.xfrm6_hdr = hdr; 361 return 0; 362 363 err_reg: 364 if (!net_eq(net, &init_net)) 365 kfree(table); 366 err_alloc: 367 return -ENOMEM; 368 } 369 370 static void __net_exit xfrm6_net_exit(struct net *net) 371 { 372 struct ctl_table *table; 373 374 if (net->ipv6.sysctl.xfrm6_hdr == NULL) 375 return; 376 377 table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg; 378 unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr); 379 if (!net_eq(net, &init_net)) 380 kfree(table); 381 } 382 383 static struct pernet_operations xfrm6_net_ops = { 384 .init = xfrm6_net_init, 385 .exit = xfrm6_net_exit, 386 }; 387 #endif 388 389 int __init xfrm6_init(void) 390 { 391 int ret; 392 393 dst_entries_init(&xfrm6_dst_ops); 394 395 ret = xfrm6_policy_init(); 396 if (ret) { 397 dst_entries_destroy(&xfrm6_dst_ops); 398 goto out; 399 } 400 ret = xfrm6_state_init(); 401 if (ret) 402 goto out_policy; 403 404 ret = xfrm6_protocol_init(); 405 if (ret) 406 goto out_state; 407 408 #ifdef CONFIG_SYSCTL 409 register_pernet_subsys(&xfrm6_net_ops); 410 #endif 411 out: 412 return ret; 413 out_state: 414 xfrm6_state_fini(); 415 out_policy: 416 xfrm6_policy_fini(); 417 goto out; 418 } 419 420 void xfrm6_fini(void) 421 { 422 #ifdef CONFIG_SYSCTL 423 unregister_pernet_subsys(&xfrm6_net_ops); 424 #endif 425 xfrm6_protocol_fini(); 426 xfrm6_policy_fini(); 427 xfrm6_state_fini(); 428 dst_entries_destroy(&xfrm6_dst_ops); 429 } 430