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 #include <net/vrf.h> 24 #if IS_ENABLED(CONFIG_IPV6_MIP6) 25 #include <net/mip6.h> 26 #endif 27 28 static struct xfrm_policy_afinfo xfrm6_policy_afinfo; 29 30 static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos, int oif, 31 const xfrm_address_t *saddr, 32 const xfrm_address_t *daddr) 33 { 34 struct flowi6 fl6; 35 struct dst_entry *dst; 36 int err; 37 38 memset(&fl6, 0, sizeof(fl6)); 39 fl6.flowi6_oif = oif; 40 fl6.flowi6_flags = FLOWI_FLAG_SKIP_NH_OIF; 41 memcpy(&fl6.daddr, daddr, sizeof(fl6.daddr)); 42 if (saddr) 43 memcpy(&fl6.saddr, saddr, sizeof(fl6.saddr)); 44 45 dst = ip6_route_output(net, NULL, &fl6); 46 47 err = dst->error; 48 if (dst->error) { 49 dst_release(dst); 50 dst = ERR_PTR(err); 51 } 52 53 return dst; 54 } 55 56 static int xfrm6_get_saddr(struct net *net, int oif, 57 xfrm_address_t *saddr, xfrm_address_t *daddr) 58 { 59 struct dst_entry *dst; 60 struct net_device *dev; 61 62 dst = xfrm6_dst_lookup(net, 0, oif, NULL, daddr); 63 if (IS_ERR(dst)) 64 return -EHOSTUNREACH; 65 66 dev = ip6_dst_idev(dst)->dev; 67 ipv6_dev_get_saddr(dev_net(dev), dev, &daddr->in6, 0, &saddr->in6); 68 dst_release(dst); 69 return 0; 70 } 71 72 static int xfrm6_get_tos(const struct flowi *fl) 73 { 74 return 0; 75 } 76 77 static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst, 78 int nfheader_len) 79 { 80 if (dst->ops->family == AF_INET6) { 81 struct rt6_info *rt = (struct rt6_info *)dst; 82 path->path_cookie = rt6_get_cookie(rt); 83 } 84 85 path->u.rt6.rt6i_nfheader_len = nfheader_len; 86 87 return 0; 88 } 89 90 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev, 91 const struct flowi *fl) 92 { 93 struct rt6_info *rt = (struct rt6_info *)xdst->route; 94 95 xdst->u.dst.dev = dev; 96 dev_hold(dev); 97 98 xdst->u.rt6.rt6i_idev = in6_dev_get(dev); 99 if (!xdst->u.rt6.rt6i_idev) { 100 dev_put(dev); 101 return -ENODEV; 102 } 103 104 /* Sheit... I remember I did this right. Apparently, 105 * it was magically lost, so this code needs audit */ 106 xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST | 107 RTF_LOCAL); 108 xdst->u.rt6.rt6i_metric = rt->rt6i_metric; 109 xdst->u.rt6.rt6i_node = rt->rt6i_node; 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; 114 115 return 0; 116 } 117 118 static inline void 119 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse) 120 { 121 struct flowi6 *fl6 = &fl->u.ip6; 122 int onlyproto = 0; 123 const struct ipv6hdr *hdr = ipv6_hdr(skb); 124 u16 offset = sizeof(*hdr); 125 struct ipv6_opt_hdr *exthdr; 126 const unsigned char *nh = skb_network_header(skb); 127 u16 nhoff = IP6CB(skb)->nhoff; 128 int oif = 0; 129 u8 nexthdr; 130 131 if (!nhoff) 132 nhoff = offsetof(struct ipv6hdr, nexthdr); 133 134 nexthdr = nh[nhoff]; 135 136 if (skb_dst(skb)) { 137 oif = vrf_master_ifindex(skb_dst(skb)->dev) ? 138 : skb_dst(skb)->dev->ifindex; 139 } 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 inline int xfrm6_garbage_collect(struct dst_ops *ops) 222 { 223 struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops); 224 225 xfrm6_policy_afinfo.garbage_collect(net); 226 return dst_entries_get_fast(ops) > ops->gc_thresh * 2; 227 } 228 229 static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk, 230 struct sk_buff *skb, u32 mtu) 231 { 232 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 233 struct dst_entry *path = xdst->route; 234 235 path->ops->update_pmtu(path, sk, skb, mtu); 236 } 237 238 static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk, 239 struct sk_buff *skb) 240 { 241 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 242 struct dst_entry *path = xdst->route; 243 244 path->ops->redirect(path, sk, skb); 245 } 246 247 static void xfrm6_dst_destroy(struct dst_entry *dst) 248 { 249 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 250 251 if (likely(xdst->u.rt6.rt6i_idev)) 252 in6_dev_put(xdst->u.rt6.rt6i_idev); 253 dst_destroy_metrics_generic(dst); 254 xfrm_dst_destroy(xdst); 255 } 256 257 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 258 int unregister) 259 { 260 struct xfrm_dst *xdst; 261 262 if (!unregister) 263 return; 264 265 xdst = (struct xfrm_dst *)dst; 266 if (xdst->u.rt6.rt6i_idev->dev == dev) { 267 struct inet6_dev *loopback_idev = 268 in6_dev_get(dev_net(dev)->loopback_dev); 269 BUG_ON(!loopback_idev); 270 271 do { 272 in6_dev_put(xdst->u.rt6.rt6i_idev); 273 xdst->u.rt6.rt6i_idev = loopback_idev; 274 in6_dev_hold(loopback_idev); 275 xdst = (struct xfrm_dst *)xdst->u.dst.child; 276 } while (xdst->u.dst.xfrm); 277 278 __in6_dev_put(loopback_idev); 279 } 280 281 xfrm_dst_ifdown(dst, dev); 282 } 283 284 static struct dst_ops xfrm6_dst_ops = { 285 .family = AF_INET6, 286 .gc = xfrm6_garbage_collect, 287 .update_pmtu = xfrm6_update_pmtu, 288 .redirect = xfrm6_redirect, 289 .cow_metrics = dst_cow_metrics_generic, 290 .destroy = xfrm6_dst_destroy, 291 .ifdown = xfrm6_dst_ifdown, 292 .local_out = __ip6_local_out, 293 .gc_thresh = 32768, 294 }; 295 296 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = { 297 .family = AF_INET6, 298 .dst_ops = &xfrm6_dst_ops, 299 .dst_lookup = xfrm6_dst_lookup, 300 .get_saddr = xfrm6_get_saddr, 301 .decode_session = _decode_session6, 302 .get_tos = xfrm6_get_tos, 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) 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 ret = xfrm6_protocol_init(); 393 if (ret) 394 goto out_state; 395 396 #ifdef CONFIG_SYSCTL 397 register_pernet_subsys(&xfrm6_net_ops); 398 #endif 399 out: 400 return ret; 401 out_state: 402 xfrm6_state_fini(); 403 out_policy: 404 xfrm6_policy_fini(); 405 goto out; 406 } 407 408 void xfrm6_fini(void) 409 { 410 #ifdef CONFIG_SYSCTL 411 unregister_pernet_subsys(&xfrm6_net_ops); 412 #endif 413 xfrm6_protocol_fini(); 414 xfrm6_policy_fini(); 415 xfrm6_state_fini(); 416 dst_entries_destroy(&xfrm6_dst_ops); 417 } 418