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 if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) { 204 struct ip6_mh *mh; 205 206 nh = skb_network_header(skb); 207 mh = (struct ip6_mh *)(nh + offset); 208 fl6->fl6_mh_type = mh->ip6mh_type; 209 } 210 fl6->flowi6_proto = nexthdr; 211 return; 212 #endif 213 214 /* XXX Why are there these headers? */ 215 case IPPROTO_AH: 216 case IPPROTO_ESP: 217 case IPPROTO_COMP: 218 default: 219 fl6->fl6_ipsec_spi = 0; 220 fl6->flowi6_proto = nexthdr; 221 return; 222 } 223 } 224 } 225 226 static inline int xfrm6_garbage_collect(struct dst_ops *ops) 227 { 228 struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops); 229 230 xfrm6_policy_afinfo.garbage_collect(net); 231 return dst_entries_get_fast(ops) > ops->gc_thresh * 2; 232 } 233 234 static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk, 235 struct sk_buff *skb, u32 mtu) 236 { 237 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 238 struct dst_entry *path = xdst->route; 239 240 path->ops->update_pmtu(path, sk, skb, mtu); 241 } 242 243 static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk, 244 struct sk_buff *skb) 245 { 246 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 247 struct dst_entry *path = xdst->route; 248 249 path->ops->redirect(path, sk, skb); 250 } 251 252 static void xfrm6_dst_destroy(struct dst_entry *dst) 253 { 254 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 255 256 if (likely(xdst->u.rt6.rt6i_idev)) 257 in6_dev_put(xdst->u.rt6.rt6i_idev); 258 dst_destroy_metrics_generic(dst); 259 if (rt6_has_peer(&xdst->u.rt6)) { 260 struct inet_peer *peer = rt6_peer_ptr(&xdst->u.rt6); 261 inet_putpeer(peer); 262 } 263 xfrm_dst_destroy(xdst); 264 } 265 266 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 267 int unregister) 268 { 269 struct xfrm_dst *xdst; 270 271 if (!unregister) 272 return; 273 274 xdst = (struct xfrm_dst *)dst; 275 if (xdst->u.rt6.rt6i_idev->dev == dev) { 276 struct inet6_dev *loopback_idev = 277 in6_dev_get(dev_net(dev)->loopback_dev); 278 BUG_ON(!loopback_idev); 279 280 do { 281 in6_dev_put(xdst->u.rt6.rt6i_idev); 282 xdst->u.rt6.rt6i_idev = loopback_idev; 283 in6_dev_hold(loopback_idev); 284 xdst = (struct xfrm_dst *)xdst->u.dst.child; 285 } while (xdst->u.dst.xfrm); 286 287 __in6_dev_put(loopback_idev); 288 } 289 290 xfrm_dst_ifdown(dst, dev); 291 } 292 293 static struct dst_ops xfrm6_dst_ops = { 294 .family = AF_INET6, 295 .protocol = cpu_to_be16(ETH_P_IPV6), 296 .gc = xfrm6_garbage_collect, 297 .update_pmtu = xfrm6_update_pmtu, 298 .redirect = xfrm6_redirect, 299 .cow_metrics = dst_cow_metrics_generic, 300 .destroy = xfrm6_dst_destroy, 301 .ifdown = xfrm6_dst_ifdown, 302 .local_out = __ip6_local_out, 303 .gc_thresh = 32768, 304 }; 305 306 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = { 307 .family = AF_INET6, 308 .dst_ops = &xfrm6_dst_ops, 309 .dst_lookup = xfrm6_dst_lookup, 310 .get_saddr = xfrm6_get_saddr, 311 .decode_session = _decode_session6, 312 .get_tos = xfrm6_get_tos, 313 .init_dst = xfrm6_init_dst, 314 .init_path = xfrm6_init_path, 315 .fill_dst = xfrm6_fill_dst, 316 .blackhole_route = ip6_blackhole_route, 317 }; 318 319 static int __init xfrm6_policy_init(void) 320 { 321 return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo); 322 } 323 324 static void xfrm6_policy_fini(void) 325 { 326 xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo); 327 } 328 329 #ifdef CONFIG_SYSCTL 330 static struct ctl_table xfrm6_policy_table[] = { 331 { 332 .procname = "xfrm6_gc_thresh", 333 .data = &init_net.xfrm.xfrm6_dst_ops.gc_thresh, 334 .maxlen = sizeof(int), 335 .mode = 0644, 336 .proc_handler = proc_dointvec, 337 }, 338 { } 339 }; 340 341 static int __net_init xfrm6_net_init(struct net *net) 342 { 343 struct ctl_table *table; 344 struct ctl_table_header *hdr; 345 346 table = xfrm6_policy_table; 347 if (!net_eq(net, &init_net)) { 348 table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL); 349 if (!table) 350 goto err_alloc; 351 352 table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh; 353 } 354 355 hdr = register_net_sysctl(net, "net/ipv6", table); 356 if (!hdr) 357 goto err_reg; 358 359 net->ipv6.sysctl.xfrm6_hdr = hdr; 360 return 0; 361 362 err_reg: 363 if (!net_eq(net, &init_net)) 364 kfree(table); 365 err_alloc: 366 return -ENOMEM; 367 } 368 369 static void __net_exit xfrm6_net_exit(struct net *net) 370 { 371 struct ctl_table *table; 372 373 if (net->ipv6.sysctl.xfrm6_hdr == NULL) 374 return; 375 376 table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg; 377 unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr); 378 if (!net_eq(net, &init_net)) 379 kfree(table); 380 } 381 382 static struct pernet_operations xfrm6_net_ops = { 383 .init = xfrm6_net_init, 384 .exit = xfrm6_net_exit, 385 }; 386 #endif 387 388 int __init xfrm6_init(void) 389 { 390 int ret; 391 392 dst_entries_init(&xfrm6_dst_ops); 393 394 ret = xfrm6_policy_init(); 395 if (ret) { 396 dst_entries_destroy(&xfrm6_dst_ops); 397 goto out; 398 } 399 ret = xfrm6_state_init(); 400 if (ret) 401 goto out_policy; 402 403 ret = xfrm6_protocol_init(); 404 if (ret) 405 goto out_state; 406 407 #ifdef CONFIG_SYSCTL 408 register_pernet_subsys(&xfrm6_net_ops); 409 #endif 410 out: 411 return ret; 412 out_state: 413 xfrm6_state_fini(); 414 out_policy: 415 xfrm6_policy_fini(); 416 goto out; 417 } 418 419 void xfrm6_fini(void) 420 { 421 #ifdef CONFIG_SYSCTL 422 unregister_pernet_subsys(&xfrm6_net_ops); 423 #endif 424 xfrm6_protocol_fini(); 425 xfrm6_policy_fini(); 426 xfrm6_state_fini(); 427 dst_entries_destroy(&xfrm6_dst_ops); 428 } 429