net/ipv6/xfrm6_policy.c

   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                 path->path_cookie = rt6_get_cookie(rt);
  89         }
  90
  91         path->u.rt6.rt6i_nfheader_len = nfheader_len;
  92
  93         return 0;
  94 }
  95
  96 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
  97                           const struct flowi *fl)
  98 {
  99         struct rt6_info *rt = (struct rt6_info*)xdst->route;
 100
 101         xdst->u.dst.dev = dev;
 102         dev_hold(dev);
 103
 104         xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
 105         if (!xdst->u.rt6.rt6i_idev) {
 106                 dev_put(dev);
 107                 return -ENODEV;
 108         }
 109
 110         rt6_transfer_peer(&xdst->u.rt6, rt);
 111
 112         /* Sheit... I remember I did this right. Apparently,
 113          * it was magically lost, so this code needs audit */
 114         xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
 115                                                    RTF_LOCAL);
 116         xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
 117         xdst->u.rt6.rt6i_node = rt->rt6i_node;
 118         xdst->route_cookie = rt6_get_cookie(rt);
 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         int oif = 0;
 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 = (__be16 *)exthdr;
 172
 173                                 fl6->fl6_sport = ports[!!reverse];
 174                                 fl6->fl6_dport = ports[!reverse];
 175                         }
 176                         fl6->flowi6_proto = nexthdr;
 177                         return;
 178
 179                 case IPPROTO_ICMPV6:
 180                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
 181                                 u8 *icmp = (u8 *)exthdr;
 182
 183                                 fl6->fl6_icmp_type = icmp[0];
 184                                 fl6->fl6_icmp_code = icmp[1];
 185                         }
 186                         fl6->flowi6_proto = nexthdr;
 187                         return;
 188
 189 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 190                 case IPPROTO_MH:
 191                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
 192                                 struct ip6_mh *mh;
 193                                 mh = (struct ip6_mh *)exthdr;
 194
 195                                 fl6->fl6_mh_type = mh->ip6mh_type;
 196                         }
 197                         fl6->flowi6_proto = nexthdr;
 198                         return;
 199 #endif
 200
 201                 /* XXX Why are there these headers? */
 202                 case IPPROTO_AH:
 203                 case IPPROTO_ESP:
 204                 case IPPROTO_COMP:
 205                 default:
 206                         fl6->fl6_ipsec_spi = 0;
 207                         fl6->flowi6_proto = nexthdr;
 208                         return;
 209                 }
 210         }
 211 }
 212
 213 static inline int xfrm6_garbage_collect(struct dst_ops *ops)
 214 {
 215         struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
 216
 217         xfrm6_policy_afinfo.garbage_collect(net);
 218         return dst_entries_get_fast(ops) > ops->gc_thresh * 2;
 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         if (rt6_has_peer(&xdst->u.rt6)) {
 247                 struct inet_peer *peer = rt6_peer_ptr(&xdst->u.rt6);
 248                 inet_putpeer(peer);
 249         }
 250         xfrm_dst_destroy(xdst);
 251 }
 252
 253 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 254                              int unregister)
 255 {
 256         struct xfrm_dst *xdst;
 257
 258         if (!unregister)
 259                 return;
 260
 261         xdst = (struct xfrm_dst *)dst;
 262         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 263                 struct inet6_dev *loopback_idev =
 264                         in6_dev_get(dev_net(dev)->loopback_dev);
 265                 BUG_ON(!loopback_idev);
 266
 267                 do {
 268                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 269                         xdst->u.rt6.rt6i_idev = loopback_idev;
 270                         in6_dev_hold(loopback_idev);
 271                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 272                 } while (xdst->u.dst.xfrm);
 273
 274                 __in6_dev_put(loopback_idev);
 275         }
 276
 277         xfrm_dst_ifdown(dst, dev);
 278 }
 279
 280 static struct dst_ops xfrm6_dst_ops_template = {
 281         .family =               AF_INET6,
 282         .protocol =             cpu_to_be16(ETH_P_IPV6),
 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_template,
 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_dst =             xfrm6_init_dst,
 301         .init_path =            xfrm6_init_path,
 302         .fill_dst =             xfrm6_fill_dst,
 303         .blackhole_route =      ip6_blackhole_route,
 304 };
 305
 306 static int __init xfrm6_policy_init(void)
 307 {
 308         return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 309 }
 310
 311 static void xfrm6_policy_fini(void)
 312 {
 313         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 314 }
 315
 316 #ifdef CONFIG_SYSCTL
 317 static struct ctl_table xfrm6_policy_table[] = {
 318         {
 319                 .procname       = "xfrm6_gc_thresh",
 320                 .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
 321                 .maxlen         = sizeof(int),
 322                 .mode           = 0644,
 323                 .proc_handler   = proc_dointvec,
 324         },
 325         { }
 326 };
 327
 328 static int __net_init xfrm6_net_sysctl_init(struct net *net)
 329 {
 330         struct ctl_table *table;
 331         struct ctl_table_header *hdr;
 332
 333         table = xfrm6_policy_table;
 334         if (!net_eq(net, &init_net)) {
 335                 table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL);
 336                 if (!table)
 337                         goto err_alloc;
 338
 339                 table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh;
 340         }
 341
 342         hdr = register_net_sysctl(net, "net/ipv6", table);
 343         if (!hdr)
 344                 goto err_reg;
 345
 346         net->ipv6.sysctl.xfrm6_hdr = hdr;
 347         return 0;
 348
 349 err_reg:
 350         if (!net_eq(net, &init_net))
 351                 kfree(table);
 352 err_alloc:
 353         return -ENOMEM;
 354 }
 355
 356 static void __net_exit xfrm6_net_sysctl_exit(struct net *net)
 357 {
 358         struct ctl_table *table;
 359
 360         if (net->ipv6.sysctl.xfrm6_hdr == NULL)
 361                 return;
 362
 363         table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg;
 364         unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr);
 365         if (!net_eq(net, &init_net))
 366                 kfree(table);
 367 }
 368 #else /* CONFIG_SYSCTL */
 369 static int inline xfrm6_net_sysctl_init(struct net *net)
 370 {
 371         return 0;
 372 }
 373
 374 static void inline xfrm6_net_sysctl_exit(struct net *net)
 375 {
 376 }
 377 #endif
 378
 379 static int __net_init xfrm6_net_init(struct net *net)
 380 {
 381         int ret;
 382
 383         memcpy(&net->xfrm.xfrm6_dst_ops, &xfrm6_dst_ops_template,
 384                sizeof(xfrm6_dst_ops_template));
 385         ret = dst_entries_init(&net->xfrm.xfrm6_dst_ops);
 386         if (ret)
 387                 return ret;
 388
 389         ret = xfrm6_net_sysctl_init(net);
 390         if (ret)
 391                 dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
 392
 393         return ret;
 394 }
 395
 396 static void __net_exit xfrm6_net_exit(struct net *net)
 397 {
 398         xfrm6_net_sysctl_exit(net);
 399         dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
 400 }
 401
 402 static struct pernet_operations xfrm6_net_ops = {
 403         .init   = xfrm6_net_init,
 404         .exit   = xfrm6_net_exit,
 405 };
 406
 407 int __init xfrm6_init(void)
 408 {
 409         int ret;
 410
 411         ret = xfrm6_policy_init();
 412         if (ret)
 413                 goto out;
 414         ret = xfrm6_state_init();
 415         if (ret)
 416                 goto out_policy;
 417
 418         ret = xfrm6_protocol_init();
 419         if (ret)
 420                 goto out_state;
 421
 422         register_pernet_subsys(&xfrm6_net_ops);
 423 out:
 424         return ret;
 425 out_state:
 426         xfrm6_state_fini();
 427 out_policy:
 428         xfrm6_policy_fini();
 429         goto out;
 430 }
 431
 432 void xfrm6_fini(void)
 433 {
 434         unregister_pernet_subsys(&xfrm6_net_ops);
 435         xfrm6_protocol_fini();
 436         xfrm6_policy_fini();
 437         xfrm6_state_fini();
 438 }