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