1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * xfrm6_policy.c: based on xfrm4_policy.c 4 * 5 * Authors: 6 * Mitsuru KANDA @USAGI 7 * Kazunori MIYAZAWA @USAGI 8 * Kunihiro Ishiguro <kunihiro@ipinfusion.com> 9 * IPv6 support 10 * YOSHIFUJI Hideaki 11 * Split up af-specific portion 12 * 13 */ 14 15 #include <linux/err.h> 16 #include <linux/kernel.h> 17 #include <linux/netdevice.h> 18 #include <net/addrconf.h> 19 #include <net/dst.h> 20 #include <net/xfrm.h> 21 #include <net/ip.h> 22 #include <net/ipv6.h> 23 #include <net/ip6_route.h> 24 #include <net/l3mdev.h> 25 #if IS_ENABLED(CONFIG_IPV6_MIP6) 26 #include <net/mip6.h> 27 #endif 28 29 static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos, int oif, 30 const xfrm_address_t *saddr, 31 const xfrm_address_t *daddr, 32 u32 mark) 33 { 34 struct flowi6 fl6; 35 struct dst_entry *dst; 36 int err; 37 38 memset(&fl6, 0, sizeof(fl6)); 39 fl6.flowi6_oif = l3mdev_master_ifindex_by_index(net, oif); 40 fl6.flowi6_flags = FLOWI_FLAG_SKIP_NH_OIF; 41 fl6.flowi6_mark = mark; 42 memcpy(&fl6.daddr, daddr, sizeof(fl6.daddr)); 43 if (saddr) 44 memcpy(&fl6.saddr, saddr, sizeof(fl6.saddr)); 45 46 dst = ip6_route_output(net, NULL, &fl6); 47 48 err = dst->error; 49 if (dst->error) { 50 dst_release(dst); 51 dst = ERR_PTR(err); 52 } 53 54 return dst; 55 } 56 57 static int xfrm6_get_saddr(struct net *net, int oif, 58 xfrm_address_t *saddr, xfrm_address_t *daddr, 59 u32 mark) 60 { 61 struct dst_entry *dst; 62 struct net_device *dev; 63 64 dst = xfrm6_dst_lookup(net, 0, oif, NULL, daddr, mark); 65 if (IS_ERR(dst)) 66 return -EHOSTUNREACH; 67 68 dev = ip6_dst_idev(dst)->dev; 69 ipv6_dev_get_saddr(dev_net(dev), dev, &daddr->in6, 0, &saddr->in6); 70 dst_release(dst); 71 return 0; 72 } 73 74 static int xfrm6_get_tos(const struct flowi *fl) 75 { 76 return 0; 77 } 78 79 static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst, 80 int nfheader_len) 81 { 82 if (dst->ops->family == AF_INET6) { 83 struct rt6_info *rt = (struct rt6_info *)dst; 84 path->path_cookie = rt6_get_cookie(rt); 85 } 86 87 path->u.rt6.rt6i_nfheader_len = nfheader_len; 88 89 return 0; 90 } 91 92 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev, 93 const struct flowi *fl) 94 { 95 struct rt6_info *rt = (struct rt6_info *)xdst->route; 96 97 xdst->u.dst.dev = dev; 98 dev_hold(dev); 99 100 xdst->u.rt6.rt6i_idev = in6_dev_get(dev); 101 if (!xdst->u.rt6.rt6i_idev) { 102 dev_put(dev); 103 return -ENODEV; 104 } 105 106 /* Sheit... I remember I did this right. Apparently, 107 * it was magically lost, so this code needs audit */ 108 xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST | 109 RTF_LOCAL); 110 xdst->u.rt6.rt6i_metric = rt->rt6i_metric; 111 xdst->u.rt6.rt6i_node = rt->rt6i_node; 112 xdst->route_cookie = rt6_get_cookie(rt); 113 xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway; 114 xdst->u.rt6.rt6i_dst = rt->rt6i_dst; 115 xdst->u.rt6.rt6i_src = rt->rt6i_src; 116 INIT_LIST_HEAD(&xdst->u.rt6.rt6i_uncached); 117 rt6_uncached_list_add(&xdst->u.rt6); 118 atomic_inc(&dev_net(dev)->ipv6.rt6_stats->fib_rt_uncache); 119 120 return 0; 121 } 122 123 static inline void 124 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse) 125 { 126 struct flowi6 *fl6 = &fl->u.ip6; 127 int onlyproto = 0; 128 const struct ipv6hdr *hdr = ipv6_hdr(skb); 129 u16 offset = sizeof(*hdr); 130 struct ipv6_opt_hdr *exthdr; 131 const unsigned char *nh = skb_network_header(skb); 132 u16 nhoff = IP6CB(skb)->nhoff; 133 int oif = 0; 134 u8 nexthdr; 135 136 if (!nhoff) 137 nhoff = offsetof(struct ipv6hdr, nexthdr); 138 139 nexthdr = nh[nhoff]; 140 141 if (skb_dst(skb)) 142 oif = skb_dst(skb)->dev->ifindex; 143 144 memset(fl6, 0, sizeof(struct flowi6)); 145 fl6->flowi6_mark = skb->mark; 146 fl6->flowi6_oif = reverse ? skb->skb_iif : oif; 147 148 fl6->daddr = reverse ? hdr->saddr : hdr->daddr; 149 fl6->saddr = reverse ? hdr->daddr : hdr->saddr; 150 151 while (nh + offset + 1 < skb->data || 152 pskb_may_pull(skb, nh + offset + 1 - skb->data)) { 153 nh = skb_network_header(skb); 154 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 155 156 switch (nexthdr) { 157 case NEXTHDR_FRAGMENT: 158 onlyproto = 1; 159 /* fall through */ 160 case NEXTHDR_ROUTING: 161 case NEXTHDR_HOP: 162 case NEXTHDR_DEST: 163 offset += ipv6_optlen(exthdr); 164 nexthdr = exthdr->nexthdr; 165 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 166 break; 167 168 case IPPROTO_UDP: 169 case IPPROTO_UDPLITE: 170 case IPPROTO_TCP: 171 case IPPROTO_SCTP: 172 case IPPROTO_DCCP: 173 if (!onlyproto && (nh + offset + 4 < skb->data || 174 pskb_may_pull(skb, nh + offset + 4 - skb->data))) { 175 __be16 *ports; 176 177 nh = skb_network_header(skb); 178 ports = (__be16 *)(nh + offset); 179 fl6->fl6_sport = ports[!!reverse]; 180 fl6->fl6_dport = ports[!reverse]; 181 } 182 fl6->flowi6_proto = nexthdr; 183 return; 184 185 case IPPROTO_ICMPV6: 186 if (!onlyproto && (nh + offset + 2 < skb->data || 187 pskb_may_pull(skb, nh + offset + 2 - skb->data))) { 188 u8 *icmp; 189 190 nh = skb_network_header(skb); 191 icmp = (u8 *)(nh + offset); 192 fl6->fl6_icmp_type = icmp[0]; 193 fl6->fl6_icmp_code = icmp[1]; 194 } 195 fl6->flowi6_proto = nexthdr; 196 return; 197 198 #if IS_ENABLED(CONFIG_IPV6_MIP6) 199 case IPPROTO_MH: 200 offset += ipv6_optlen(exthdr); 201 if (!onlyproto && (nh + offset + 3 < skb->data || 202 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 void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk, 226 struct sk_buff *skb, u32 mtu) 227 { 228 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 229 struct dst_entry *path = xdst->route; 230 231 path->ops->update_pmtu(path, sk, skb, mtu); 232 } 233 234 static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk, 235 struct sk_buff *skb) 236 { 237 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 238 struct dst_entry *path = xdst->route; 239 240 path->ops->redirect(path, sk, skb); 241 } 242 243 static void xfrm6_dst_destroy(struct dst_entry *dst) 244 { 245 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 246 247 if (likely(xdst->u.rt6.rt6i_idev)) 248 in6_dev_put(xdst->u.rt6.rt6i_idev); 249 dst_destroy_metrics_generic(dst); 250 if (xdst->u.rt6.rt6i_uncached_list) 251 rt6_uncached_list_del(&xdst->u.rt6); 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 *)xfrm_dst_child(&xdst->u.dst); 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 .update_pmtu = xfrm6_update_pmtu, 285 .redirect = xfrm6_redirect, 286 .cow_metrics = dst_cow_metrics_generic, 287 .destroy = xfrm6_dst_destroy, 288 .ifdown = xfrm6_dst_ifdown, 289 .local_out = __ip6_local_out, 290 .gc_thresh = 32768, 291 }; 292 293 static const struct xfrm_policy_afinfo xfrm6_policy_afinfo = { 294 .dst_ops = &xfrm6_dst_ops_template, 295 .dst_lookup = xfrm6_dst_lookup, 296 .get_saddr = xfrm6_get_saddr, 297 .decode_session = _decode_session6, 298 .get_tos = xfrm6_get_tos, 299 .init_path = xfrm6_init_path, 300 .fill_dst = xfrm6_fill_dst, 301 .blackhole_route = ip6_blackhole_route, 302 }; 303 304 static int __init xfrm6_policy_init(void) 305 { 306 return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo, AF_INET6); 307 } 308 309 static void xfrm6_policy_fini(void) 310 { 311 xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo); 312 } 313 314 #ifdef CONFIG_SYSCTL 315 static struct ctl_table xfrm6_policy_table[] = { 316 { 317 .procname = "xfrm6_gc_thresh", 318 .data = &init_net.xfrm.xfrm6_dst_ops.gc_thresh, 319 .maxlen = sizeof(int), 320 .mode = 0644, 321 .proc_handler = proc_dointvec, 322 }, 323 { } 324 }; 325 326 static int __net_init xfrm6_net_sysctl_init(struct net *net) 327 { 328 struct ctl_table *table; 329 struct ctl_table_header *hdr; 330 331 table = xfrm6_policy_table; 332 if (!net_eq(net, &init_net)) { 333 table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL); 334 if (!table) 335 goto err_alloc; 336 337 table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh; 338 } 339 340 hdr = register_net_sysctl(net, "net/ipv6", table); 341 if (!hdr) 342 goto err_reg; 343 344 net->ipv6.sysctl.xfrm6_hdr = hdr; 345 return 0; 346 347 err_reg: 348 if (!net_eq(net, &init_net)) 349 kfree(table); 350 err_alloc: 351 return -ENOMEM; 352 } 353 354 static void __net_exit xfrm6_net_sysctl_exit(struct net *net) 355 { 356 struct ctl_table *table; 357 358 if (!net->ipv6.sysctl.xfrm6_hdr) 359 return; 360 361 table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg; 362 unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr); 363 if (!net_eq(net, &init_net)) 364 kfree(table); 365 } 366 #else /* CONFIG_SYSCTL */ 367 static inline int xfrm6_net_sysctl_init(struct net *net) 368 { 369 return 0; 370 } 371 372 static inline void xfrm6_net_sysctl_exit(struct net *net) 373 { 374 } 375 #endif 376 377 static int __net_init xfrm6_net_init(struct net *net) 378 { 379 int ret; 380 381 memcpy(&net->xfrm.xfrm6_dst_ops, &xfrm6_dst_ops_template, 382 sizeof(xfrm6_dst_ops_template)); 383 ret = dst_entries_init(&net->xfrm.xfrm6_dst_ops); 384 if (ret) 385 return ret; 386 387 ret = xfrm6_net_sysctl_init(net); 388 if (ret) 389 dst_entries_destroy(&net->xfrm.xfrm6_dst_ops); 390 391 return ret; 392 } 393 394 static void __net_exit xfrm6_net_exit(struct net *net) 395 { 396 xfrm6_net_sysctl_exit(net); 397 dst_entries_destroy(&net->xfrm.xfrm6_dst_ops); 398 } 399 400 static struct pernet_operations xfrm6_net_ops = { 401 .init = xfrm6_net_init, 402 .exit = xfrm6_net_exit, 403 }; 404 405 int __init xfrm6_init(void) 406 { 407 int ret; 408 409 ret = xfrm6_policy_init(); 410 if (ret) 411 goto out; 412 ret = xfrm6_state_init(); 413 if (ret) 414 goto out_policy; 415 416 ret = xfrm6_protocol_init(); 417 if (ret) 418 goto out_state; 419 420 register_pernet_subsys(&xfrm6_net_ops); 421 out: 422 return ret; 423 out_state: 424 xfrm6_state_fini(); 425 out_policy: 426 xfrm6_policy_fini(); 427 goto out; 428 } 429 430 void xfrm6_fini(void) 431 { 432 unregister_pernet_subsys(&xfrm6_net_ops); 433 xfrm6_protocol_fini(); 434 xfrm6_policy_fini(); 435 xfrm6_state_fini(); 436 } 437