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->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 INIT_LIST_HEAD(&xdst->u.rt6.rt6i_uncached); 115 rt6_uncached_list_add(&xdst->u.rt6); 116 atomic_inc(&dev_net(dev)->ipv6.rt6_stats->fib_rt_uncache); 117 118 return 0; 119 } 120 121 static inline void 122 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse) 123 { 124 struct flowi6 *fl6 = &fl->u.ip6; 125 int onlyproto = 0; 126 const struct ipv6hdr *hdr = ipv6_hdr(skb); 127 u32 offset = sizeof(*hdr); 128 struct ipv6_opt_hdr *exthdr; 129 const unsigned char *nh = skb_network_header(skb); 130 u16 nhoff = IP6CB(skb)->nhoff; 131 int oif = 0; 132 u8 nexthdr; 133 134 if (!nhoff) 135 nhoff = offsetof(struct ipv6hdr, nexthdr); 136 137 nexthdr = nh[nhoff]; 138 139 if (skb_dst(skb)) 140 oif = skb_dst(skb)->dev->ifindex; 141 142 memset(fl6, 0, sizeof(struct flowi6)); 143 fl6->flowi6_mark = skb->mark; 144 fl6->flowi6_oif = reverse ? skb->skb_iif : oif; 145 146 fl6->daddr = reverse ? hdr->saddr : hdr->daddr; 147 fl6->saddr = reverse ? hdr->daddr : hdr->saddr; 148 149 while (nh + offset + 1 < skb->data || 150 pskb_may_pull(skb, nh + offset + 1 - skb->data)) { 151 nh = skb_network_header(skb); 152 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 153 154 switch (nexthdr) { 155 case NEXTHDR_FRAGMENT: 156 onlyproto = 1; 157 /* fall through */ 158 case NEXTHDR_ROUTING: 159 case NEXTHDR_HOP: 160 case NEXTHDR_DEST: 161 offset += ipv6_optlen(exthdr); 162 nexthdr = exthdr->nexthdr; 163 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 164 break; 165 166 case IPPROTO_UDP: 167 case IPPROTO_UDPLITE: 168 case IPPROTO_TCP: 169 case IPPROTO_SCTP: 170 case IPPROTO_DCCP: 171 if (!onlyproto && (nh + offset + 4 < skb->data || 172 pskb_may_pull(skb, nh + offset + 4 - skb->data))) { 173 __be16 *ports; 174 175 nh = skb_network_header(skb); 176 ports = (__be16 *)(nh + offset); 177 fl6->fl6_sport = ports[!!reverse]; 178 fl6->fl6_dport = ports[!reverse]; 179 } 180 fl6->flowi6_proto = nexthdr; 181 return; 182 183 case IPPROTO_ICMPV6: 184 if (!onlyproto && (nh + offset + 2 < skb->data || 185 pskb_may_pull(skb, nh + offset + 2 - skb->data))) { 186 u8 *icmp; 187 188 nh = skb_network_header(skb); 189 icmp = (u8 *)(nh + offset); 190 fl6->fl6_icmp_type = icmp[0]; 191 fl6->fl6_icmp_code = icmp[1]; 192 } 193 fl6->flowi6_proto = nexthdr; 194 return; 195 196 #if IS_ENABLED(CONFIG_IPV6_MIP6) 197 case IPPROTO_MH: 198 offset += ipv6_optlen(exthdr); 199 if (!onlyproto && (nh + offset + 3 < skb->data || 200 pskb_may_pull(skb, nh + offset + 3 - skb->data))) { 201 struct ip6_mh *mh; 202 203 nh = skb_network_header(skb); 204 mh = (struct ip6_mh *)(nh + offset); 205 fl6->fl6_mh_type = mh->ip6mh_type; 206 } 207 fl6->flowi6_proto = nexthdr; 208 return; 209 #endif 210 211 /* XXX Why are there these headers? */ 212 case IPPROTO_AH: 213 case IPPROTO_ESP: 214 case IPPROTO_COMP: 215 default: 216 fl6->fl6_ipsec_spi = 0; 217 fl6->flowi6_proto = nexthdr; 218 return; 219 } 220 } 221 } 222 223 static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk, 224 struct sk_buff *skb, u32 mtu) 225 { 226 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 227 struct dst_entry *path = xdst->route; 228 229 path->ops->update_pmtu(path, sk, skb, mtu); 230 } 231 232 static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk, 233 struct sk_buff *skb) 234 { 235 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 236 struct dst_entry *path = xdst->route; 237 238 path->ops->redirect(path, sk, skb); 239 } 240 241 static void xfrm6_dst_destroy(struct dst_entry *dst) 242 { 243 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 244 245 if (likely(xdst->u.rt6.rt6i_idev)) 246 in6_dev_put(xdst->u.rt6.rt6i_idev); 247 dst_destroy_metrics_generic(dst); 248 if (xdst->u.rt6.rt6i_uncached_list) 249 rt6_uncached_list_del(&xdst->u.rt6); 250 xfrm_dst_destroy(xdst); 251 } 252 253 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 254 int unregister) 255 { 256 struct xfrm_dst *xdst; 257 258 if (!unregister) 259 return; 260 261 xdst = (struct xfrm_dst *)dst; 262 if (xdst->u.rt6.rt6i_idev->dev == dev) { 263 struct inet6_dev *loopback_idev = 264 in6_dev_get(dev_net(dev)->loopback_dev); 265 BUG_ON(!loopback_idev); 266 267 do { 268 in6_dev_put(xdst->u.rt6.rt6i_idev); 269 xdst->u.rt6.rt6i_idev = loopback_idev; 270 in6_dev_hold(loopback_idev); 271 xdst = (struct xfrm_dst *)xfrm_dst_child(&xdst->u.dst); 272 } while (xdst->u.dst.xfrm); 273 274 __in6_dev_put(loopback_idev); 275 } 276 277 xfrm_dst_ifdown(dst, dev); 278 } 279 280 static struct dst_ops xfrm6_dst_ops_template = { 281 .family = AF_INET6, 282 .update_pmtu = xfrm6_update_pmtu, 283 .redirect = xfrm6_redirect, 284 .cow_metrics = dst_cow_metrics_generic, 285 .destroy = xfrm6_dst_destroy, 286 .ifdown = xfrm6_dst_ifdown, 287 .local_out = __ip6_local_out, 288 .gc_thresh = 32768, 289 }; 290 291 static const struct xfrm_policy_afinfo xfrm6_policy_afinfo = { 292 .dst_ops = &xfrm6_dst_ops_template, 293 .dst_lookup = xfrm6_dst_lookup, 294 .get_saddr = xfrm6_get_saddr, 295 .decode_session = _decode_session6, 296 .get_tos = xfrm6_get_tos, 297 .init_path = xfrm6_init_path, 298 .fill_dst = xfrm6_fill_dst, 299 .blackhole_route = ip6_blackhole_route, 300 }; 301 302 static int __init xfrm6_policy_init(void) 303 { 304 return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo, AF_INET6); 305 } 306 307 static void xfrm6_policy_fini(void) 308 { 309 xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo); 310 } 311 312 #ifdef CONFIG_SYSCTL 313 static struct ctl_table xfrm6_policy_table[] = { 314 { 315 .procname = "xfrm6_gc_thresh", 316 .data = &init_net.xfrm.xfrm6_dst_ops.gc_thresh, 317 .maxlen = sizeof(int), 318 .mode = 0644, 319 .proc_handler = proc_dointvec, 320 }, 321 { } 322 }; 323 324 static int __net_init xfrm6_net_sysctl_init(struct net *net) 325 { 326 struct ctl_table *table; 327 struct ctl_table_header *hdr; 328 329 table = xfrm6_policy_table; 330 if (!net_eq(net, &init_net)) { 331 table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL); 332 if (!table) 333 goto err_alloc; 334 335 table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh; 336 } 337 338 hdr = register_net_sysctl(net, "net/ipv6", table); 339 if (!hdr) 340 goto err_reg; 341 342 net->ipv6.sysctl.xfrm6_hdr = hdr; 343 return 0; 344 345 err_reg: 346 if (!net_eq(net, &init_net)) 347 kfree(table); 348 err_alloc: 349 return -ENOMEM; 350 } 351 352 static void __net_exit xfrm6_net_sysctl_exit(struct net *net) 353 { 354 struct ctl_table *table; 355 356 if (!net->ipv6.sysctl.xfrm6_hdr) 357 return; 358 359 table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg; 360 unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr); 361 if (!net_eq(net, &init_net)) 362 kfree(table); 363 } 364 #else /* CONFIG_SYSCTL */ 365 static inline int xfrm6_net_sysctl_init(struct net *net) 366 { 367 return 0; 368 } 369 370 static inline void xfrm6_net_sysctl_exit(struct net *net) 371 { 372 } 373 #endif 374 375 static int __net_init xfrm6_net_init(struct net *net) 376 { 377 int ret; 378 379 memcpy(&net->xfrm.xfrm6_dst_ops, &xfrm6_dst_ops_template, 380 sizeof(xfrm6_dst_ops_template)); 381 ret = dst_entries_init(&net->xfrm.xfrm6_dst_ops); 382 if (ret) 383 return ret; 384 385 ret = xfrm6_net_sysctl_init(net); 386 if (ret) 387 dst_entries_destroy(&net->xfrm.xfrm6_dst_ops); 388 389 return ret; 390 } 391 392 static void __net_exit xfrm6_net_exit(struct net *net) 393 { 394 xfrm6_net_sysctl_exit(net); 395 dst_entries_destroy(&net->xfrm.xfrm6_dst_ops); 396 } 397 398 static struct pernet_operations xfrm6_net_ops = { 399 .init = xfrm6_net_init, 400 .exit = xfrm6_net_exit, 401 }; 402 403 int __init xfrm6_init(void) 404 { 405 int ret; 406 407 ret = xfrm6_policy_init(); 408 if (ret) 409 goto out; 410 ret = xfrm6_state_init(); 411 if (ret) 412 goto out_policy; 413 414 ret = xfrm6_protocol_init(); 415 if (ret) 416 goto out_state; 417 418 register_pernet_subsys(&xfrm6_net_ops); 419 out: 420 return ret; 421 out_state: 422 xfrm6_state_fini(); 423 out_policy: 424 xfrm6_policy_fini(); 425 goto out; 426 } 427 428 void xfrm6_fini(void) 429 { 430 unregister_pernet_subsys(&xfrm6_net_ops); 431 xfrm6_protocol_fini(); 432 xfrm6_policy_fini(); 433 xfrm6_state_fini(); 434 } 435