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 #if IS_ENABLED(CONFIG_IPV6_MIP6) 24 #include <net/mip6.h> 25 #endif 26 27 static struct xfrm_policy_afinfo xfrm6_policy_afinfo; 28 29 static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos, 30 const xfrm_address_t *saddr, 31 const xfrm_address_t *daddr) 32 { 33 struct flowi6 fl6; 34 struct dst_entry *dst; 35 int err; 36 37 memset(&fl6, 0, sizeof(fl6)); 38 memcpy(&fl6.daddr, daddr, sizeof(fl6.daddr)); 39 if (saddr) 40 memcpy(&fl6.saddr, saddr, sizeof(fl6.saddr)); 41 42 dst = ip6_route_output(net, NULL, &fl6); 43 44 err = dst->error; 45 if (dst->error) { 46 dst_release(dst); 47 dst = ERR_PTR(err); 48 } 49 50 return dst; 51 } 52 53 static int xfrm6_get_saddr(struct net *net, 54 xfrm_address_t *saddr, xfrm_address_t *daddr) 55 { 56 struct dst_entry *dst; 57 struct net_device *dev; 58 59 dst = xfrm6_dst_lookup(net, 0, NULL, daddr); 60 if (IS_ERR(dst)) 61 return -EHOSTUNREACH; 62 63 dev = ip6_dst_idev(dst)->dev; 64 ipv6_dev_get_saddr(dev_net(dev), dev, 65 (struct in6_addr *)&daddr->a6, 0, 66 (struct in6_addr *)&saddr->a6); 67 dst_release(dst); 68 return 0; 69 } 70 71 static int xfrm6_get_tos(const struct flowi *fl) 72 { 73 return 0; 74 } 75 76 static void xfrm6_init_dst(struct net *net, struct xfrm_dst *xdst) 77 { 78 struct rt6_info *rt = (struct rt6_info *)xdst; 79 80 rt6_init_peer(rt, net->ipv6.peers); 81 } 82 83 static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst, 84 int nfheader_len) 85 { 86 if (dst->ops->family == AF_INET6) { 87 struct rt6_info *rt = (struct rt6_info*)dst; 88 if (rt->rt6i_node) 89 path->path_cookie = rt->rt6i_node->fn_sernum; 90 } 91 92 path->u.rt6.rt6i_nfheader_len = nfheader_len; 93 94 return 0; 95 } 96 97 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev, 98 const struct flowi *fl) 99 { 100 struct rt6_info *rt = (struct rt6_info*)xdst->route; 101 102 xdst->u.dst.dev = dev; 103 dev_hold(dev); 104 105 xdst->u.rt6.rt6i_idev = in6_dev_get(dev); 106 if (!xdst->u.rt6.rt6i_idev) { 107 dev_put(dev); 108 return -ENODEV; 109 } 110 111 rt6_transfer_peer(&xdst->u.rt6, rt); 112 113 /* Sheit... I remember I did this right. Apparently, 114 * it was magically lost, so this code needs audit */ 115 xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST | 116 RTF_LOCAL); 117 xdst->u.rt6.rt6i_metric = rt->rt6i_metric; 118 xdst->u.rt6.rt6i_node = rt->rt6i_node; 119 if (rt->rt6i_node) 120 xdst->route_cookie = rt->rt6i_node->fn_sernum; 121 xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway; 122 xdst->u.rt6.rt6i_dst = rt->rt6i_dst; 123 xdst->u.rt6.rt6i_src = rt->rt6i_src; 124 125 return 0; 126 } 127 128 static inline void 129 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse) 130 { 131 struct flowi6 *fl6 = &fl->u.ip6; 132 int onlyproto = 0; 133 u16 offset = skb_network_header_len(skb); 134 const struct ipv6hdr *hdr = ipv6_hdr(skb); 135 struct ipv6_opt_hdr *exthdr; 136 const unsigned char *nh = skb_network_header(skb); 137 u8 nexthdr = nh[IP6CB(skb)->nhoff]; 138 int oif = 0; 139 140 if (skb_dst(skb)) 141 oif = skb_dst(skb)->dev->ifindex; 142 143 memset(fl6, 0, sizeof(struct flowi6)); 144 fl6->flowi6_mark = skb->mark; 145 fl6->flowi6_oif = reverse ? skb->skb_iif : oif; 146 147 fl6->daddr = reverse ? hdr->saddr : hdr->daddr; 148 fl6->saddr = reverse ? hdr->daddr : hdr->saddr; 149 150 while (nh + offset + 1 < skb->data || 151 pskb_may_pull(skb, nh + offset + 1 - skb->data)) { 152 nh = skb_network_header(skb); 153 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 154 155 switch (nexthdr) { 156 case NEXTHDR_FRAGMENT: 157 onlyproto = 1; 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 = (__be16 *)exthdr; 174 175 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 && pskb_may_pull(skb, nh + offset + 2 - skb->data)) { 183 u8 *icmp = (u8 *)exthdr; 184 185 fl6->fl6_icmp_type = icmp[0]; 186 fl6->fl6_icmp_code = icmp[1]; 187 } 188 fl6->flowi6_proto = nexthdr; 189 return; 190 191 #if IS_ENABLED(CONFIG_IPV6_MIP6) 192 case IPPROTO_MH: 193 if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) { 194 struct ip6_mh *mh; 195 mh = (struct ip6_mh *)exthdr; 196 197 fl6->fl6_mh_type = mh->ip6mh_type; 198 } 199 fl6->flowi6_proto = nexthdr; 200 return; 201 #endif 202 203 /* XXX Why are there these headers? */ 204 case IPPROTO_AH: 205 case IPPROTO_ESP: 206 case IPPROTO_COMP: 207 default: 208 fl6->fl6_ipsec_spi = 0; 209 fl6->flowi6_proto = nexthdr; 210 return; 211 } 212 } 213 } 214 215 static inline int xfrm6_garbage_collect(struct dst_ops *ops) 216 { 217 struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops); 218 219 xfrm6_policy_afinfo.garbage_collect(net); 220 return dst_entries_get_fast(ops) > ops->gc_thresh * 2; 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 (rt6_has_peer(&xdst->u.rt6)) { 249 struct inet_peer *peer = rt6_peer_ptr(&xdst->u.rt6); 250 inet_putpeer(peer); 251 } 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 = { 283 .family = AF_INET6, 284 .protocol = cpu_to_be16(ETH_P_IPV6), 285 .gc = xfrm6_garbage_collect, 286 .update_pmtu = xfrm6_update_pmtu, 287 .redirect = xfrm6_redirect, 288 .cow_metrics = dst_cow_metrics_generic, 289 .destroy = xfrm6_dst_destroy, 290 .ifdown = xfrm6_dst_ifdown, 291 .local_out = __ip6_local_out, 292 .gc_thresh = 32768, 293 }; 294 295 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = { 296 .family = AF_INET6, 297 .dst_ops = &xfrm6_dst_ops, 298 .dst_lookup = xfrm6_dst_lookup, 299 .get_saddr = xfrm6_get_saddr, 300 .decode_session = _decode_session6, 301 .get_tos = xfrm6_get_tos, 302 .init_dst = xfrm6_init_dst, 303 .init_path = xfrm6_init_path, 304 .fill_dst = xfrm6_fill_dst, 305 .blackhole_route = ip6_blackhole_route, 306 }; 307 308 static int __init xfrm6_policy_init(void) 309 { 310 return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo); 311 } 312 313 static void xfrm6_policy_fini(void) 314 { 315 xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo); 316 } 317 318 #ifdef CONFIG_SYSCTL 319 static struct ctl_table xfrm6_policy_table[] = { 320 { 321 .procname = "xfrm6_gc_thresh", 322 .data = &init_net.xfrm.xfrm6_dst_ops.gc_thresh, 323 .maxlen = sizeof(int), 324 .mode = 0644, 325 .proc_handler = proc_dointvec, 326 }, 327 { } 328 }; 329 330 static int __net_init xfrm6_net_init(struct net *net) 331 { 332 struct ctl_table *table; 333 struct ctl_table_header *hdr; 334 335 table = xfrm6_policy_table; 336 if (!net_eq(net, &init_net)) { 337 table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL); 338 if (!table) 339 goto err_alloc; 340 341 table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh; 342 } 343 344 hdr = register_net_sysctl(net, "net/ipv6", table); 345 if (!hdr) 346 goto err_reg; 347 348 net->ipv6.sysctl.xfrm6_hdr = hdr; 349 return 0; 350 351 err_reg: 352 if (!net_eq(net, &init_net)) 353 kfree(table); 354 err_alloc: 355 return -ENOMEM; 356 } 357 358 static void __net_exit xfrm6_net_exit(struct net *net) 359 { 360 struct ctl_table *table; 361 362 if (net->ipv6.sysctl.xfrm6_hdr == NULL) 363 return; 364 365 table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg; 366 unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr); 367 if (!net_eq(net, &init_net)) 368 kfree(table); 369 } 370 371 static struct pernet_operations xfrm6_net_ops = { 372 .init = xfrm6_net_init, 373 .exit = xfrm6_net_exit, 374 }; 375 #endif 376 377 int __init xfrm6_init(void) 378 { 379 int ret; 380 381 dst_entries_init(&xfrm6_dst_ops); 382 383 ret = xfrm6_policy_init(); 384 if (ret) { 385 dst_entries_destroy(&xfrm6_dst_ops); 386 goto out; 387 } 388 ret = xfrm6_state_init(); 389 if (ret) 390 goto out_policy; 391 392 #ifdef CONFIG_SYSCTL 393 register_pernet_subsys(&xfrm6_net_ops); 394 #endif 395 out: 396 return ret; 397 out_policy: 398 xfrm6_policy_fini(); 399 goto out; 400 } 401 402 void xfrm6_fini(void) 403 { 404 #ifdef CONFIG_SYSCTL 405 unregister_pernet_subsys(&xfrm6_net_ops); 406 #endif 407 xfrm6_policy_fini(); 408 xfrm6_state_fini(); 409 dst_entries_destroy(&xfrm6_dst_ops); 410 } 411