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 #include <net/l3mdev.h> 24 #if IS_ENABLED(CONFIG_IPV6_MIP6) 25 #include <net/mip6.h> 26 #endif 27 28 static struct xfrm_policy_afinfo xfrm6_policy_afinfo; 29 30 static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos, int oif, 31 const xfrm_address_t *saddr, 32 const xfrm_address_t *daddr) 33 { 34 struct flowi6 fl6; 35 struct dst_entry *dst; 36 int err; 37 38 memset(&fl6, 0, sizeof(fl6)); 39 fl6.flowi6_oif = oif; 40 fl6.flowi6_flags = FLOWI_FLAG_SKIP_NH_OIF; 41 memcpy(&fl6.daddr, daddr, sizeof(fl6.daddr)); 42 if (saddr) 43 memcpy(&fl6.saddr, saddr, sizeof(fl6.saddr)); 44 45 dst = ip6_route_output(net, NULL, &fl6); 46 47 err = dst->error; 48 if (dst->error) { 49 dst_release(dst); 50 dst = ERR_PTR(err); 51 } 52 53 return dst; 54 } 55 56 static int xfrm6_get_saddr(struct net *net, int oif, 57 xfrm_address_t *saddr, xfrm_address_t *daddr) 58 { 59 struct dst_entry *dst; 60 struct net_device *dev; 61 62 dst = xfrm6_dst_lookup(net, 0, oif, NULL, daddr); 63 if (IS_ERR(dst)) 64 return -EHOSTUNREACH; 65 66 dev = ip6_dst_idev(dst)->dev; 67 ipv6_dev_get_saddr(dev_net(dev), dev, &daddr->in6, 0, &saddr->in6); 68 dst_release(dst); 69 return 0; 70 } 71 72 static int xfrm6_get_tos(const struct flowi *fl) 73 { 74 return 0; 75 } 76 77 static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst, 78 int nfheader_len) 79 { 80 if (dst->ops->family == AF_INET6) { 81 struct rt6_info *rt = (struct rt6_info *)dst; 82 path->path_cookie = rt6_get_cookie(rt); 83 } 84 85 path->u.rt6.rt6i_nfheader_len = nfheader_len; 86 87 return 0; 88 } 89 90 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev, 91 const struct flowi *fl) 92 { 93 struct rt6_info *rt = (struct rt6_info *)xdst->route; 94 95 xdst->u.dst.dev = dev; 96 dev_hold(dev); 97 98 xdst->u.rt6.rt6i_idev = in6_dev_get(dev); 99 if (!xdst->u.rt6.rt6i_idev) { 100 dev_put(dev); 101 return -ENODEV; 102 } 103 104 /* Sheit... I remember I did this right. Apparently, 105 * it was magically lost, so this code needs audit */ 106 xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST | 107 RTF_LOCAL); 108 xdst->u.rt6.rt6i_metric = rt->rt6i_metric; 109 xdst->u.rt6.rt6i_node = rt->rt6i_node; 110 xdst->route_cookie = rt6_get_cookie(rt); 111 xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway; 112 xdst->u.rt6.rt6i_dst = rt->rt6i_dst; 113 xdst->u.rt6.rt6i_src = rt->rt6i_src; 114 115 return 0; 116 } 117 118 static inline void 119 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse) 120 { 121 struct flowi6 *fl6 = &fl->u.ip6; 122 int onlyproto = 0; 123 const struct ipv6hdr *hdr = ipv6_hdr(skb); 124 u16 offset = sizeof(*hdr); 125 struct ipv6_opt_hdr *exthdr; 126 const unsigned char *nh = skb_network_header(skb); 127 u16 nhoff = IP6CB(skb)->nhoff; 128 int oif = 0; 129 u8 nexthdr; 130 131 if (!nhoff) 132 nhoff = offsetof(struct ipv6hdr, nexthdr); 133 134 nexthdr = nh[nhoff]; 135 136 if (skb_dst(skb)) 137 oif = l3mdev_fib_oif(skb_dst(skb)->dev); 138 139 memset(fl6, 0, sizeof(struct flowi6)); 140 fl6->flowi6_mark = skb->mark; 141 fl6->flowi6_oif = reverse ? skb->skb_iif : oif; 142 143 fl6->daddr = reverse ? hdr->saddr : hdr->daddr; 144 fl6->saddr = reverse ? hdr->daddr : hdr->saddr; 145 146 while (nh + offset + 1 < skb->data || 147 pskb_may_pull(skb, nh + offset + 1 - skb->data)) { 148 nh = skb_network_header(skb); 149 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 150 151 switch (nexthdr) { 152 case NEXTHDR_FRAGMENT: 153 onlyproto = 1; 154 case NEXTHDR_ROUTING: 155 case NEXTHDR_HOP: 156 case NEXTHDR_DEST: 157 offset += ipv6_optlen(exthdr); 158 nexthdr = exthdr->nexthdr; 159 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 160 break; 161 162 case IPPROTO_UDP: 163 case IPPROTO_UDPLITE: 164 case IPPROTO_TCP: 165 case IPPROTO_SCTP: 166 case IPPROTO_DCCP: 167 if (!onlyproto && (nh + offset + 4 < skb->data || 168 pskb_may_pull(skb, nh + offset + 4 - skb->data))) { 169 __be16 *ports; 170 171 nh = skb_network_header(skb); 172 ports = (__be16 *)(nh + offset); 173 fl6->fl6_sport = ports[!!reverse]; 174 fl6->fl6_dport = ports[!reverse]; 175 } 176 fl6->flowi6_proto = nexthdr; 177 return; 178 179 case IPPROTO_ICMPV6: 180 if (!onlyproto && (nh + offset + 2 < skb->data || 181 pskb_may_pull(skb, nh + offset + 2 - skb->data))) { 182 u8 *icmp; 183 184 nh = skb_network_header(skb); 185 icmp = (u8 *)(nh + offset); 186 fl6->fl6_icmp_type = icmp[0]; 187 fl6->fl6_icmp_code = icmp[1]; 188 } 189 fl6->flowi6_proto = nexthdr; 190 return; 191 192 #if IS_ENABLED(CONFIG_IPV6_MIP6) 193 case IPPROTO_MH: 194 offset += ipv6_optlen(exthdr); 195 if (!onlyproto && (nh + offset + 3 < skb->data || 196 pskb_may_pull(skb, nh + offset + 3 - skb->data))) { 197 struct ip6_mh *mh; 198 199 nh = skb_network_header(skb); 200 mh = (struct ip6_mh *)(nh + offset); 201 fl6->fl6_mh_type = mh->ip6mh_type; 202 } 203 fl6->flowi6_proto = nexthdr; 204 return; 205 #endif 206 207 /* XXX Why are there these headers? */ 208 case IPPROTO_AH: 209 case IPPROTO_ESP: 210 case IPPROTO_COMP: 211 default: 212 fl6->fl6_ipsec_spi = 0; 213 fl6->flowi6_proto = nexthdr; 214 return; 215 } 216 } 217 } 218 219 static inline int xfrm6_garbage_collect(struct dst_ops *ops) 220 { 221 struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops); 222 223 xfrm6_policy_afinfo.garbage_collect(net); 224 return dst_entries_get_fast(ops) > ops->gc_thresh * 2; 225 } 226 227 static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk, 228 struct sk_buff *skb, u32 mtu) 229 { 230 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 231 struct dst_entry *path = xdst->route; 232 233 path->ops->update_pmtu(path, sk, skb, mtu); 234 } 235 236 static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk, 237 struct sk_buff *skb) 238 { 239 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 240 struct dst_entry *path = xdst->route; 241 242 path->ops->redirect(path, sk, skb); 243 } 244 245 static void xfrm6_dst_destroy(struct dst_entry *dst) 246 { 247 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 248 249 if (likely(xdst->u.rt6.rt6i_idev)) 250 in6_dev_put(xdst->u.rt6.rt6i_idev); 251 dst_destroy_metrics_generic(dst); 252 xfrm_dst_destroy(xdst); 253 } 254 255 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 256 int unregister) 257 { 258 struct xfrm_dst *xdst; 259 260 if (!unregister) 261 return; 262 263 xdst = (struct xfrm_dst *)dst; 264 if (xdst->u.rt6.rt6i_idev->dev == dev) { 265 struct inet6_dev *loopback_idev = 266 in6_dev_get(dev_net(dev)->loopback_dev); 267 BUG_ON(!loopback_idev); 268 269 do { 270 in6_dev_put(xdst->u.rt6.rt6i_idev); 271 xdst->u.rt6.rt6i_idev = loopback_idev; 272 in6_dev_hold(loopback_idev); 273 xdst = (struct xfrm_dst *)xdst->u.dst.child; 274 } while (xdst->u.dst.xfrm); 275 276 __in6_dev_put(loopback_idev); 277 } 278 279 xfrm_dst_ifdown(dst, dev); 280 } 281 282 static struct dst_ops xfrm6_dst_ops_template = { 283 .family = AF_INET6, 284 .gc = xfrm6_garbage_collect, 285 .update_pmtu = xfrm6_update_pmtu, 286 .redirect = xfrm6_redirect, 287 .cow_metrics = dst_cow_metrics_generic, 288 .destroy = xfrm6_dst_destroy, 289 .ifdown = xfrm6_dst_ifdown, 290 .local_out = __ip6_local_out, 291 .gc_thresh = INT_MAX, 292 }; 293 294 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = { 295 .family = AF_INET6, 296 .dst_ops = &xfrm6_dst_ops_template, 297 .dst_lookup = xfrm6_dst_lookup, 298 .get_saddr = xfrm6_get_saddr, 299 .decode_session = _decode_session6, 300 .get_tos = xfrm6_get_tos, 301 .init_path = xfrm6_init_path, 302 .fill_dst = xfrm6_fill_dst, 303 .blackhole_route = ip6_blackhole_route, 304 }; 305 306 static int __init xfrm6_policy_init(void) 307 { 308 return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo); 309 } 310 311 static void xfrm6_policy_fini(void) 312 { 313 xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo); 314 } 315 316 #ifdef CONFIG_SYSCTL 317 static struct ctl_table xfrm6_policy_table[] = { 318 { 319 .procname = "xfrm6_gc_thresh", 320 .data = &init_net.xfrm.xfrm6_dst_ops.gc_thresh, 321 .maxlen = sizeof(int), 322 .mode = 0644, 323 .proc_handler = proc_dointvec, 324 }, 325 { } 326 }; 327 328 static int __net_init xfrm6_net_sysctl_init(struct net *net) 329 { 330 struct ctl_table *table; 331 struct ctl_table_header *hdr; 332 333 table = xfrm6_policy_table; 334 if (!net_eq(net, &init_net)) { 335 table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL); 336 if (!table) 337 goto err_alloc; 338 339 table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh; 340 } 341 342 hdr = register_net_sysctl(net, "net/ipv6", table); 343 if (!hdr) 344 goto err_reg; 345 346 net->ipv6.sysctl.xfrm6_hdr = hdr; 347 return 0; 348 349 err_reg: 350 if (!net_eq(net, &init_net)) 351 kfree(table); 352 err_alloc: 353 return -ENOMEM; 354 } 355 356 static void __net_exit xfrm6_net_sysctl_exit(struct net *net) 357 { 358 struct ctl_table *table; 359 360 if (!net->ipv6.sysctl.xfrm6_hdr) 361 return; 362 363 table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg; 364 unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr); 365 if (!net_eq(net, &init_net)) 366 kfree(table); 367 } 368 #else /* CONFIG_SYSCTL */ 369 static int inline xfrm6_net_sysctl_init(struct net *net) 370 { 371 return 0; 372 } 373 374 static void inline xfrm6_net_sysctl_exit(struct net *net) 375 { 376 } 377 #endif 378 379 static int __net_init xfrm6_net_init(struct net *net) 380 { 381 int ret; 382 383 memcpy(&net->xfrm.xfrm6_dst_ops, &xfrm6_dst_ops_template, 384 sizeof(xfrm6_dst_ops_template)); 385 ret = dst_entries_init(&net->xfrm.xfrm6_dst_ops); 386 if (ret) 387 return ret; 388 389 ret = xfrm6_net_sysctl_init(net); 390 if (ret) 391 dst_entries_destroy(&net->xfrm.xfrm6_dst_ops); 392 393 return ret; 394 } 395 396 static void __net_exit xfrm6_net_exit(struct net *net) 397 { 398 xfrm6_net_sysctl_exit(net); 399 dst_entries_destroy(&net->xfrm.xfrm6_dst_ops); 400 } 401 402 static struct pernet_operations xfrm6_net_ops = { 403 .init = xfrm6_net_init, 404 .exit = xfrm6_net_exit, 405 }; 406 407 int __init xfrm6_init(void) 408 { 409 int ret; 410 411 ret = xfrm6_policy_init(); 412 if (ret) 413 goto out; 414 ret = xfrm6_state_init(); 415 if (ret) 416 goto out_policy; 417 418 ret = xfrm6_protocol_init(); 419 if (ret) 420 goto out_state; 421 422 register_pernet_subsys(&xfrm6_net_ops); 423 out: 424 return ret; 425 out_state: 426 xfrm6_state_fini(); 427 out_policy: 428 xfrm6_policy_fini(); 429 goto out; 430 } 431 432 void xfrm6_fini(void) 433 { 434 unregister_pernet_subsys(&xfrm6_net_ops); 435 xfrm6_protocol_fini(); 436 xfrm6_policy_fini(); 437 xfrm6_state_fini(); 438 } 439