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 memcpy(&fl6.daddr, daddr, sizeof(fl6.daddr)); 41 if (saddr) 42 memcpy(&fl6.saddr, saddr, sizeof(fl6.saddr)); 43 44 dst = ip6_route_output(net, NULL, &fl6); 45 46 err = dst->error; 47 if (dst->error) { 48 dst_release(dst); 49 dst = ERR_PTR(err); 50 } 51 52 return dst; 53 } 54 55 static int xfrm6_get_saddr(struct net *net, int oif, 56 xfrm_address_t *saddr, xfrm_address_t *daddr) 57 { 58 struct dst_entry *dst; 59 struct net_device *dev; 60 61 dst = xfrm6_dst_lookup(net, 0, oif, NULL, daddr); 62 if (IS_ERR(dst)) 63 return -EHOSTUNREACH; 64 65 dev = ip6_dst_idev(dst)->dev; 66 ipv6_dev_get_saddr(dev_net(dev), dev, &daddr->in6, 0, &saddr->in6); 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 int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst, 77 int nfheader_len) 78 { 79 if (dst->ops->family == AF_INET6) { 80 struct rt6_info *rt = (struct rt6_info *)dst; 81 path->path_cookie = rt6_get_cookie(rt); 82 } 83 84 path->u.rt6.rt6i_nfheader_len = nfheader_len; 85 86 return 0; 87 } 88 89 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev, 90 const struct flowi *fl) 91 { 92 struct rt6_info *rt = (struct rt6_info *)xdst->route; 93 94 xdst->u.dst.dev = dev; 95 dev_hold(dev); 96 97 xdst->u.rt6.rt6i_idev = in6_dev_get(dev); 98 if (!xdst->u.rt6.rt6i_idev) { 99 dev_put(dev); 100 return -ENODEV; 101 } 102 103 /* Sheit... I remember I did this right. Apparently, 104 * it was magically lost, so this code needs audit */ 105 xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST | 106 RTF_LOCAL); 107 xdst->u.rt6.rt6i_metric = rt->rt6i_metric; 108 xdst->u.rt6.rt6i_node = rt->rt6i_node; 109 xdst->route_cookie = rt6_get_cookie(rt); 110 xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway; 111 xdst->u.rt6.rt6i_dst = rt->rt6i_dst; 112 xdst->u.rt6.rt6i_src = rt->rt6i_src; 113 114 return 0; 115 } 116 117 static inline void 118 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse) 119 { 120 struct flowi6 *fl6 = &fl->u.ip6; 121 int onlyproto = 0; 122 const struct ipv6hdr *hdr = ipv6_hdr(skb); 123 u16 offset = sizeof(*hdr); 124 struct ipv6_opt_hdr *exthdr; 125 const unsigned char *nh = skb_network_header(skb); 126 u16 nhoff = IP6CB(skb)->nhoff; 127 int oif = 0; 128 u8 nexthdr; 129 130 if (!nhoff) 131 nhoff = offsetof(struct ipv6hdr, nexthdr); 132 133 nexthdr = nh[nhoff]; 134 135 if (skb_dst(skb)) { 136 oif = vrf_master_ifindex(skb_dst(skb)->dev) ? 137 : skb_dst(skb)->dev->ifindex; 138 } 139 140 memset(fl6, 0, sizeof(struct flowi6)); 141 fl6->flowi6_mark = skb->mark; 142 fl6->flowi6_oif = reverse ? skb->skb_iif : oif; 143 144 fl6->daddr = reverse ? hdr->saddr : hdr->daddr; 145 fl6->saddr = reverse ? hdr->daddr : hdr->saddr; 146 147 while (nh + offset + 1 < skb->data || 148 pskb_may_pull(skb, nh + offset + 1 - skb->data)) { 149 nh = skb_network_header(skb); 150 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 151 152 switch (nexthdr) { 153 case NEXTHDR_FRAGMENT: 154 onlyproto = 1; 155 case NEXTHDR_ROUTING: 156 case NEXTHDR_HOP: 157 case NEXTHDR_DEST: 158 offset += ipv6_optlen(exthdr); 159 nexthdr = exthdr->nexthdr; 160 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 161 break; 162 163 case IPPROTO_UDP: 164 case IPPROTO_UDPLITE: 165 case IPPROTO_TCP: 166 case IPPROTO_SCTP: 167 case IPPROTO_DCCP: 168 if (!onlyproto && (nh + offset + 4 < skb->data || 169 pskb_may_pull(skb, nh + offset + 4 - skb->data))) { 170 __be16 *ports; 171 172 nh = skb_network_header(skb); 173 ports = (__be16 *)(nh + offset); 174 fl6->fl6_sport = ports[!!reverse]; 175 fl6->fl6_dport = ports[!reverse]; 176 } 177 fl6->flowi6_proto = nexthdr; 178 return; 179 180 case IPPROTO_ICMPV6: 181 if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) { 182 u8 *icmp; 183 184 nh = skb_network_header(skb); 185 icmp = (u8 *)(nh + offset); 186 fl6->fl6_icmp_type = icmp[0]; 187 fl6->fl6_icmp_code = icmp[1]; 188 } 189 fl6->flowi6_proto = nexthdr; 190 return; 191 192 #if IS_ENABLED(CONFIG_IPV6_MIP6) 193 case IPPROTO_MH: 194 offset += ipv6_optlen(exthdr); 195 if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) { 196 struct ip6_mh *mh; 197 198 nh = skb_network_header(skb); 199 mh = (struct ip6_mh *)(nh + offset); 200 fl6->fl6_mh_type = mh->ip6mh_type; 201 } 202 fl6->flowi6_proto = nexthdr; 203 return; 204 #endif 205 206 /* XXX Why are there these headers? */ 207 case IPPROTO_AH: 208 case IPPROTO_ESP: 209 case IPPROTO_COMP: 210 default: 211 fl6->fl6_ipsec_spi = 0; 212 fl6->flowi6_proto = nexthdr; 213 return; 214 } 215 } 216 } 217 218 static inline int xfrm6_garbage_collect(struct dst_ops *ops) 219 { 220 struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops); 221 222 xfrm6_policy_afinfo.garbage_collect(net); 223 return dst_entries_get_fast(ops) > ops->gc_thresh * 2; 224 } 225 226 static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk, 227 struct sk_buff *skb, u32 mtu) 228 { 229 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 230 struct dst_entry *path = xdst->route; 231 232 path->ops->update_pmtu(path, sk, skb, mtu); 233 } 234 235 static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk, 236 struct sk_buff *skb) 237 { 238 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 239 struct dst_entry *path = xdst->route; 240 241 path->ops->redirect(path, sk, skb); 242 } 243 244 static void xfrm6_dst_destroy(struct dst_entry *dst) 245 { 246 struct xfrm_dst *xdst = (struct xfrm_dst *)dst; 247 248 if (likely(xdst->u.rt6.rt6i_idev)) 249 in6_dev_put(xdst->u.rt6.rt6i_idev); 250 dst_destroy_metrics_generic(dst); 251 xfrm_dst_destroy(xdst); 252 } 253 254 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev, 255 int unregister) 256 { 257 struct xfrm_dst *xdst; 258 259 if (!unregister) 260 return; 261 262 xdst = (struct xfrm_dst *)dst; 263 if (xdst->u.rt6.rt6i_idev->dev == dev) { 264 struct inet6_dev *loopback_idev = 265 in6_dev_get(dev_net(dev)->loopback_dev); 266 BUG_ON(!loopback_idev); 267 268 do { 269 in6_dev_put(xdst->u.rt6.rt6i_idev); 270 xdst->u.rt6.rt6i_idev = loopback_idev; 271 in6_dev_hold(loopback_idev); 272 xdst = (struct xfrm_dst *)xdst->u.dst.child; 273 } while (xdst->u.dst.xfrm); 274 275 __in6_dev_put(loopback_idev); 276 } 277 278 xfrm_dst_ifdown(dst, dev); 279 } 280 281 static struct dst_ops xfrm6_dst_ops = { 282 .family = AF_INET6, 283 .gc = xfrm6_garbage_collect, 284 .update_pmtu = xfrm6_update_pmtu, 285 .redirect = xfrm6_redirect, 286 .cow_metrics = dst_cow_metrics_generic, 287 .destroy = xfrm6_dst_destroy, 288 .ifdown = xfrm6_dst_ifdown, 289 .local_out = __ip6_local_out, 290 .gc_thresh = 32768, 291 }; 292 293 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = { 294 .family = AF_INET6, 295 .dst_ops = &xfrm6_dst_ops, 296 .dst_lookup = xfrm6_dst_lookup, 297 .get_saddr = xfrm6_get_saddr, 298 .decode_session = _decode_session6, 299 .get_tos = xfrm6_get_tos, 300 .init_path = xfrm6_init_path, 301 .fill_dst = xfrm6_fill_dst, 302 .blackhole_route = ip6_blackhole_route, 303 }; 304 305 static int __init xfrm6_policy_init(void) 306 { 307 return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo); 308 } 309 310 static void xfrm6_policy_fini(void) 311 { 312 xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo); 313 } 314 315 #ifdef CONFIG_SYSCTL 316 static struct ctl_table xfrm6_policy_table[] = { 317 { 318 .procname = "xfrm6_gc_thresh", 319 .data = &init_net.xfrm.xfrm6_dst_ops.gc_thresh, 320 .maxlen = sizeof(int), 321 .mode = 0644, 322 .proc_handler = proc_dointvec, 323 }, 324 { } 325 }; 326 327 static int __net_init xfrm6_net_init(struct net *net) 328 { 329 struct ctl_table *table; 330 struct ctl_table_header *hdr; 331 332 table = xfrm6_policy_table; 333 if (!net_eq(net, &init_net)) { 334 table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL); 335 if (!table) 336 goto err_alloc; 337 338 table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh; 339 } 340 341 hdr = register_net_sysctl(net, "net/ipv6", table); 342 if (!hdr) 343 goto err_reg; 344 345 net->ipv6.sysctl.xfrm6_hdr = hdr; 346 return 0; 347 348 err_reg: 349 if (!net_eq(net, &init_net)) 350 kfree(table); 351 err_alloc: 352 return -ENOMEM; 353 } 354 355 static void __net_exit xfrm6_net_exit(struct net *net) 356 { 357 struct ctl_table *table; 358 359 if (!net->ipv6.sysctl.xfrm6_hdr) 360 return; 361 362 table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg; 363 unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr); 364 if (!net_eq(net, &init_net)) 365 kfree(table); 366 } 367 368 static struct pernet_operations xfrm6_net_ops = { 369 .init = xfrm6_net_init, 370 .exit = xfrm6_net_exit, 371 }; 372 #endif 373 374 int __init xfrm6_init(void) 375 { 376 int ret; 377 378 dst_entries_init(&xfrm6_dst_ops); 379 380 ret = xfrm6_policy_init(); 381 if (ret) { 382 dst_entries_destroy(&xfrm6_dst_ops); 383 goto out; 384 } 385 ret = xfrm6_state_init(); 386 if (ret) 387 goto out_policy; 388 389 ret = xfrm6_protocol_init(); 390 if (ret) 391 goto out_state; 392 393 #ifdef CONFIG_SYSCTL 394 register_pernet_subsys(&xfrm6_net_ops); 395 #endif 396 out: 397 return ret; 398 out_state: 399 xfrm6_state_fini(); 400 out_policy: 401 xfrm6_policy_fini(); 402 goto out; 403 } 404 405 void xfrm6_fini(void) 406 { 407 #ifdef CONFIG_SYSCTL 408 unregister_pernet_subsys(&xfrm6_net_ops); 409 #endif 410 xfrm6_protocol_fini(); 411 xfrm6_policy_fini(); 412 xfrm6_state_fini(); 413 dst_entries_destroy(&xfrm6_dst_ops); 414 } 415