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, &daddr->in6, 0, &saddr->in6); 65 dst_release(dst); 66 return 0; 67 } 68 69 static int xfrm6_get_tos(const struct flowi *fl) 70 { 71 return 0; 72 } 73 74 static void xfrm6_init_dst(struct net *net, struct xfrm_dst *xdst) 75 { 76 struct rt6_info *rt = (struct rt6_info *)xdst; 77 78 rt6_init_peer(rt, net->ipv6.peers); 79 } 80 81 static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst, 82 int nfheader_len) 83 { 84 if (dst->ops->family == AF_INET6) { 85 struct rt6_info *rt = (struct rt6_info *)dst; 86 if (rt->rt6i_node) 87 path->path_cookie = rt->rt6i_node->fn_sernum; 88 } 89 90 path->u.rt6.rt6i_nfheader_len = nfheader_len; 91 92 return 0; 93 } 94 95 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev, 96 const struct flowi *fl) 97 { 98 struct rt6_info *rt = (struct rt6_info *)xdst->route; 99 100 xdst->u.dst.dev = dev; 101 dev_hold(dev); 102 103 xdst->u.rt6.rt6i_idev = in6_dev_get(dev); 104 if (!xdst->u.rt6.rt6i_idev) { 105 dev_put(dev); 106 return -ENODEV; 107 } 108 109 rt6_transfer_peer(&xdst->u.rt6, rt); 110 111 /* Sheit... I remember I did this right. Apparently, 112 * it was magically lost, so this code needs audit */ 113 xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST | 114 RTF_LOCAL); 115 xdst->u.rt6.rt6i_metric = rt->rt6i_metric; 116 xdst->u.rt6.rt6i_node = rt->rt6i_node; 117 if (rt->rt6i_node) 118 xdst->route_cookie = rt->rt6i_node->fn_sernum; 119 xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway; 120 xdst->u.rt6.rt6i_dst = rt->rt6i_dst; 121 xdst->u.rt6.rt6i_src = rt->rt6i_src; 122 123 return 0; 124 } 125 126 static inline void 127 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse) 128 { 129 struct flowi6 *fl6 = &fl->u.ip6; 130 int onlyproto = 0; 131 const struct ipv6hdr *hdr = ipv6_hdr(skb); 132 u16 offset = sizeof(*hdr); 133 struct ipv6_opt_hdr *exthdr; 134 const unsigned char *nh = skb_network_header(skb); 135 u16 nhoff = IP6CB(skb)->nhoff; 136 int oif = 0; 137 u8 nexthdr; 138 139 if (!nhoff) 140 nhoff = offsetof(struct ipv6hdr, nexthdr); 141 142 nexthdr = nh[nhoff]; 143 144 if (skb_dst(skb)) 145 oif = skb_dst(skb)->dev->ifindex; 146 147 memset(fl6, 0, sizeof(struct flowi6)); 148 fl6->flowi6_mark = skb->mark; 149 fl6->flowi6_oif = reverse ? skb->skb_iif : oif; 150 151 fl6->daddr = reverse ? hdr->saddr : hdr->daddr; 152 fl6->saddr = reverse ? hdr->daddr : hdr->saddr; 153 154 while (nh + offset + 1 < skb->data || 155 pskb_may_pull(skb, nh + offset + 1 - skb->data)) { 156 nh = skb_network_header(skb); 157 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 158 159 switch (nexthdr) { 160 case NEXTHDR_FRAGMENT: 161 onlyproto = 1; 162 case NEXTHDR_ROUTING: 163 case NEXTHDR_HOP: 164 case NEXTHDR_DEST: 165 offset += ipv6_optlen(exthdr); 166 nexthdr = exthdr->nexthdr; 167 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 168 break; 169 170 case IPPROTO_UDP: 171 case IPPROTO_UDPLITE: 172 case IPPROTO_TCP: 173 case IPPROTO_SCTP: 174 case IPPROTO_DCCP: 175 if (!onlyproto && (nh + offset + 4 < skb->data || 176 pskb_may_pull(skb, nh + offset + 4 - skb->data))) { 177 __be16 *ports; 178 179 nh = skb_network_header(skb); 180 ports = (__be16 *)(nh + offset); 181 fl6->fl6_sport = ports[!!reverse]; 182 fl6->fl6_dport = ports[!reverse]; 183 } 184 fl6->flowi6_proto = nexthdr; 185 return; 186 187 case IPPROTO_ICMPV6: 188 if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) { 189 u8 *icmp; 190 191 nh = skb_network_header(skb); 192 icmp = (u8 *)(nh + offset); 193 fl6->fl6_icmp_type = icmp[0]; 194 fl6->fl6_icmp_code = icmp[1]; 195 } 196 fl6->flowi6_proto = nexthdr; 197 return; 198 199 #if IS_ENABLED(CONFIG_IPV6_MIP6) 200 case IPPROTO_MH: 201 offset += ipv6_optlen(exthdr); 202 if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) { 203 struct ip6_mh *mh; 204 205 nh = skb_network_header(skb); 206 mh = (struct ip6_mh *)(nh + offset); 207 fl6->fl6_mh_type = mh->ip6mh_type; 208 } 209 fl6->flowi6_proto = nexthdr; 210 return; 211 #endif 212 213 /* XXX Why are there these headers? */ 214 case IPPROTO_AH: 215 case IPPROTO_ESP: 216 case IPPROTO_COMP: 217 default: 218 fl6->fl6_ipsec_spi = 0; 219 fl6->flowi6_proto = nexthdr; 220 return; 221 } 222 } 223 } 224 225 static inline int xfrm6_garbage_collect(struct dst_ops *ops) 226 { 227 struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops); 228 229 xfrm6_policy_afinfo.garbage_collect(net); 230 return dst_entries_get_fast(ops) > ops->gc_thresh * 2; 231 } 232 233 static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk, 234 struct sk_buff *skb, u32 mtu) 235 { 236 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 237 struct dst_entry *path = xdst->route; 238 239 path->ops->update_pmtu(path, sk, skb, mtu); 240 } 241 242 static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk, 243 struct sk_buff *skb) 244 { 245 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 246 struct dst_entry *path = xdst->route; 247 248 path->ops->redirect(path, sk, skb); 249 } 250 251 static void xfrm6_dst_destroy(struct dst_entry *dst) 252 { 253 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 254 255 if (likely(xdst->u.rt6.rt6i_idev)) 256 in6_dev_put(xdst->u.rt6.rt6i_idev); 257 dst_destroy_metrics_generic(dst); 258 if (rt6_has_peer(&xdst->u.rt6)) { 259 struct inet_peer *peer = rt6_peer_ptr(&xdst->u.rt6); 260 inet_putpeer(peer); 261 } 262 xfrm_dst_destroy(xdst); 263 } 264 265 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 266 int unregister) 267 { 268 struct xfrm_dst *xdst; 269 270 if (!unregister) 271 return; 272 273 xdst = (struct xfrm_dst *)dst; 274 if (xdst->u.rt6.rt6i_idev->dev == dev) { 275 struct inet6_dev *loopback_idev = 276 in6_dev_get(dev_net(dev)->loopback_dev); 277 BUG_ON(!loopback_idev); 278 279 do { 280 in6_dev_put(xdst->u.rt6.rt6i_idev); 281 xdst->u.rt6.rt6i_idev = loopback_idev; 282 in6_dev_hold(loopback_idev); 283 xdst = (struct xfrm_dst *)xdst->u.dst.child; 284 } while (xdst->u.dst.xfrm); 285 286 __in6_dev_put(loopback_idev); 287 } 288 289 xfrm_dst_ifdown(dst, dev); 290 } 291 292 static struct dst_ops xfrm6_dst_ops = { 293 .family = AF_INET6, 294 .gc = xfrm6_garbage_collect, 295 .update_pmtu = xfrm6_update_pmtu, 296 .redirect = xfrm6_redirect, 297 .cow_metrics = dst_cow_metrics_generic, 298 .destroy = xfrm6_dst_destroy, 299 .ifdown = xfrm6_dst_ifdown, 300 .local_out = __ip6_local_out, 301 .gc_thresh = 32768, 302 }; 303 304 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = { 305 .family = AF_INET6, 306 .dst_ops = &xfrm6_dst_ops, 307 .dst_lookup = xfrm6_dst_lookup, 308 .get_saddr = xfrm6_get_saddr, 309 .decode_session = _decode_session6, 310 .get_tos = xfrm6_get_tos, 311 .init_dst = xfrm6_init_dst, 312 .init_path = xfrm6_init_path, 313 .fill_dst = xfrm6_fill_dst, 314 .blackhole_route = ip6_blackhole_route, 315 }; 316 317 static int __init xfrm6_policy_init(void) 318 { 319 return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo); 320 } 321 322 static void xfrm6_policy_fini(void) 323 { 324 xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo); 325 } 326 327 #ifdef CONFIG_SYSCTL 328 static struct ctl_table xfrm6_policy_table[] = { 329 { 330 .procname = "xfrm6_gc_thresh", 331 .data = &init_net.xfrm.xfrm6_dst_ops.gc_thresh, 332 .maxlen = sizeof(int), 333 .mode = 0644, 334 .proc_handler = proc_dointvec, 335 }, 336 { } 337 }; 338 339 static int __net_init xfrm6_net_init(struct net *net) 340 { 341 struct ctl_table *table; 342 struct ctl_table_header *hdr; 343 344 table = xfrm6_policy_table; 345 if (!net_eq(net, &init_net)) { 346 table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL); 347 if (!table) 348 goto err_alloc; 349 350 table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh; 351 } 352 353 hdr = register_net_sysctl(net, "net/ipv6", table); 354 if (!hdr) 355 goto err_reg; 356 357 net->ipv6.sysctl.xfrm6_hdr = hdr; 358 return 0; 359 360 err_reg: 361 if (!net_eq(net, &init_net)) 362 kfree(table); 363 err_alloc: 364 return -ENOMEM; 365 } 366 367 static void __net_exit xfrm6_net_exit(struct net *net) 368 { 369 struct ctl_table *table; 370 371 if (!net->ipv6.sysctl.xfrm6_hdr) 372 return; 373 374 table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg; 375 unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr); 376 if (!net_eq(net, &init_net)) 377 kfree(table); 378 } 379 380 static struct pernet_operations xfrm6_net_ops = { 381 .init = xfrm6_net_init, 382 .exit = xfrm6_net_exit, 383 }; 384 #endif 385 386 int __init xfrm6_init(void) 387 { 388 int ret; 389 390 dst_entries_init(&xfrm6_dst_ops); 391 392 ret = xfrm6_policy_init(); 393 if (ret) { 394 dst_entries_destroy(&xfrm6_dst_ops); 395 goto out; 396 } 397 ret = xfrm6_state_init(); 398 if (ret) 399 goto out_policy; 400 401 ret = xfrm6_protocol_init(); 402 if (ret) 403 goto out_state; 404 405 #ifdef CONFIG_SYSCTL 406 register_pernet_subsys(&xfrm6_net_ops); 407 #endif 408 out: 409 return ret; 410 out_state: 411 xfrm6_state_fini(); 412 out_policy: 413 xfrm6_policy_fini(); 414 goto out; 415 } 416 417 void xfrm6_fini(void) 418 { 419 #ifdef CONFIG_SYSCTL 420 unregister_pernet_subsys(&xfrm6_net_ops); 421 #endif 422 xfrm6_protocol_fini(); 423 xfrm6_policy_fini(); 424 xfrm6_state_fini(); 425 dst_entries_destroy(&xfrm6_dst_ops); 426 } 427