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