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 return -ENODEV; 108 109 rt6_transfer_peer(&xdst->u.rt6, rt); 110 111 /* Sheit... I remember I did this right. Apparently, 112 * it was magically lost, so this code needs audit */ 113 xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST | 114 RTF_LOCAL); 115 xdst->u.rt6.rt6i_metric = rt->rt6i_metric; 116 xdst->u.rt6.rt6i_node = rt->rt6i_node; 117 if (rt->rt6i_node) 118 xdst->route_cookie = rt->rt6i_node->fn_sernum; 119 xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway; 120 xdst->u.rt6.rt6i_dst = rt->rt6i_dst; 121 xdst->u.rt6.rt6i_src = rt->rt6i_src; 122 123 return 0; 124 } 125 126 static inline void 127 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse) 128 { 129 struct flowi6 *fl6 = &fl->u.ip6; 130 int onlyproto = 0; 131 u16 offset = skb_network_header_len(skb); 132 const struct ipv6hdr *hdr = ipv6_hdr(skb); 133 struct ipv6_opt_hdr *exthdr; 134 const unsigned char *nh = skb_network_header(skb); 135 u8 nexthdr = nh[IP6CB(skb)->nhoff]; 136 137 memset(fl6, 0, sizeof(struct flowi6)); 138 fl6->flowi6_mark = skb->mark; 139 140 fl6->daddr = reverse ? hdr->saddr : hdr->daddr; 141 fl6->saddr = reverse ? hdr->daddr : hdr->saddr; 142 143 while (nh + offset + 1 < skb->data || 144 pskb_may_pull(skb, nh + offset + 1 - skb->data)) { 145 nh = skb_network_header(skb); 146 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 147 148 switch (nexthdr) { 149 case NEXTHDR_FRAGMENT: 150 onlyproto = 1; 151 case NEXTHDR_ROUTING: 152 case NEXTHDR_HOP: 153 case NEXTHDR_DEST: 154 offset += ipv6_optlen(exthdr); 155 nexthdr = exthdr->nexthdr; 156 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 157 break; 158 159 case IPPROTO_UDP: 160 case IPPROTO_UDPLITE: 161 case IPPROTO_TCP: 162 case IPPROTO_SCTP: 163 case IPPROTO_DCCP: 164 if (!onlyproto && (nh + offset + 4 < skb->data || 165 pskb_may_pull(skb, nh + offset + 4 - skb->data))) { 166 __be16 *ports = (__be16 *)exthdr; 167 168 fl6->fl6_sport = ports[!!reverse]; 169 fl6->fl6_dport = ports[!reverse]; 170 } 171 fl6->flowi6_proto = nexthdr; 172 return; 173 174 case IPPROTO_ICMPV6: 175 if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) { 176 u8 *icmp = (u8 *)exthdr; 177 178 fl6->fl6_icmp_type = icmp[0]; 179 fl6->fl6_icmp_code = icmp[1]; 180 } 181 fl6->flowi6_proto = nexthdr; 182 return; 183 184 #if IS_ENABLED(CONFIG_IPV6_MIP6) 185 case IPPROTO_MH: 186 if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) { 187 struct ip6_mh *mh; 188 mh = (struct ip6_mh *)exthdr; 189 190 fl6->fl6_mh_type = mh->ip6mh_type; 191 } 192 fl6->flowi6_proto = nexthdr; 193 return; 194 #endif 195 196 /* XXX Why are there these headers? */ 197 case IPPROTO_AH: 198 case IPPROTO_ESP: 199 case IPPROTO_COMP: 200 default: 201 fl6->fl6_ipsec_spi = 0; 202 fl6->flowi6_proto = nexthdr; 203 return; 204 } 205 } 206 } 207 208 static inline int xfrm6_garbage_collect(struct dst_ops *ops) 209 { 210 struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops); 211 212 xfrm6_policy_afinfo.garbage_collect(net); 213 return dst_entries_get_fast(ops) > ops->gc_thresh * 2; 214 } 215 216 static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk, 217 struct sk_buff *skb, u32 mtu) 218 { 219 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 220 struct dst_entry *path = xdst->route; 221 222 path->ops->update_pmtu(path, sk, skb, mtu); 223 } 224 225 static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk, 226 struct sk_buff *skb) 227 { 228 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 229 struct dst_entry *path = xdst->route; 230 231 path->ops->redirect(path, sk, skb); 232 } 233 234 static void xfrm6_dst_destroy(struct dst_entry *dst) 235 { 236 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 237 238 if (likely(xdst->u.rt6.rt6i_idev)) 239 in6_dev_put(xdst->u.rt6.rt6i_idev); 240 dst_destroy_metrics_generic(dst); 241 if (rt6_has_peer(&xdst->u.rt6)) { 242 struct inet_peer *peer = rt6_peer_ptr(&xdst->u.rt6); 243 inet_putpeer(peer); 244 } 245 xfrm_dst_destroy(xdst); 246 } 247 248 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 249 int unregister) 250 { 251 struct xfrm_dst *xdst; 252 253 if (!unregister) 254 return; 255 256 xdst = (struct xfrm_dst *)dst; 257 if (xdst->u.rt6.rt6i_idev->dev == dev) { 258 struct inet6_dev *loopback_idev = 259 in6_dev_get(dev_net(dev)->loopback_dev); 260 BUG_ON(!loopback_idev); 261 262 do { 263 in6_dev_put(xdst->u.rt6.rt6i_idev); 264 xdst->u.rt6.rt6i_idev = loopback_idev; 265 in6_dev_hold(loopback_idev); 266 xdst = (struct xfrm_dst *)xdst->u.dst.child; 267 } while (xdst->u.dst.xfrm); 268 269 __in6_dev_put(loopback_idev); 270 } 271 272 xfrm_dst_ifdown(dst, dev); 273 } 274 275 static struct dst_ops xfrm6_dst_ops = { 276 .family = AF_INET6, 277 .protocol = cpu_to_be16(ETH_P_IPV6), 278 .gc = xfrm6_garbage_collect, 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 = 1024, 286 }; 287 288 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = { 289 .family = AF_INET6, 290 .dst_ops = &xfrm6_dst_ops, 291 .dst_lookup = xfrm6_dst_lookup, 292 .get_saddr = xfrm6_get_saddr, 293 .decode_session = _decode_session6, 294 .get_tos = xfrm6_get_tos, 295 .init_dst = xfrm6_init_dst, 296 .init_path = xfrm6_init_path, 297 .fill_dst = xfrm6_fill_dst, 298 .blackhole_route = ip6_blackhole_route, 299 }; 300 301 static int __init xfrm6_policy_init(void) 302 { 303 return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo); 304 } 305 306 static void xfrm6_policy_fini(void) 307 { 308 xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo); 309 } 310 311 #ifdef CONFIG_SYSCTL 312 static struct ctl_table xfrm6_policy_table[] = { 313 { 314 .procname = "xfrm6_gc_thresh", 315 .data = &init_net.xfrm.xfrm6_dst_ops.gc_thresh, 316 .maxlen = sizeof(int), 317 .mode = 0644, 318 .proc_handler = proc_dointvec, 319 }, 320 { } 321 }; 322 323 static int __net_init xfrm6_net_init(struct net *net) 324 { 325 struct ctl_table *table; 326 struct ctl_table_header *hdr; 327 328 table = xfrm6_policy_table; 329 if (!net_eq(net, &init_net)) { 330 table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL); 331 if (!table) 332 goto err_alloc; 333 334 table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh; 335 } 336 337 hdr = register_net_sysctl(net, "net/ipv6", table); 338 if (!hdr) 339 goto err_reg; 340 341 net->ipv6.sysctl.xfrm6_hdr = hdr; 342 return 0; 343 344 err_reg: 345 if (!net_eq(net, &init_net)) 346 kfree(table); 347 err_alloc: 348 return -ENOMEM; 349 } 350 351 static void __net_exit xfrm6_net_exit(struct net *net) 352 { 353 struct ctl_table *table; 354 355 if (net->ipv6.sysctl.xfrm6_hdr == NULL) 356 return; 357 358 table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg; 359 unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr); 360 if (!net_eq(net, &init_net)) 361 kfree(table); 362 } 363 364 static struct pernet_operations xfrm6_net_ops = { 365 .init = xfrm6_net_init, 366 .exit = xfrm6_net_exit, 367 }; 368 #endif 369 370 int __init xfrm6_init(void) 371 { 372 int ret; 373 374 dst_entries_init(&xfrm6_dst_ops); 375 376 ret = xfrm6_policy_init(); 377 if (ret) { 378 dst_entries_destroy(&xfrm6_dst_ops); 379 goto out; 380 } 381 ret = xfrm6_state_init(); 382 if (ret) 383 goto out_policy; 384 385 #ifdef CONFIG_SYSCTL 386 register_pernet_subsys(&xfrm6_net_ops); 387 #endif 388 out: 389 return ret; 390 out_policy: 391 xfrm6_policy_fini(); 392 goto out; 393 } 394 395 void xfrm6_fini(void) 396 { 397 #ifdef CONFIG_SYSCTL 398 unregister_pernet_subsys(&xfrm6_net_ops); 399 #endif 400 xfrm6_policy_fini(); 401 xfrm6_state_fini(); 402 dst_entries_destroy(&xfrm6_dst_ops); 403 } 404