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 #include <net/l3mdev.h>
  24 #if IS_ENABLED(CONFIG_IPV6_MIP6)
  25 #include <net/mip6.h>
  26 #endif
  27
  28 static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos, int oif,
  29                                           const xfrm_address_t *saddr,
  30                                           const xfrm_address_t *daddr)
  31 {
  32         struct flowi6 fl6;
  33         struct dst_entry *dst;
  34         int err;
  35
  36         memset(&fl6, 0, sizeof(fl6));
  37         fl6.flowi6_oif = l3mdev_master_ifindex_by_index(net, oif);
  38         fl6.flowi6_flags = FLOWI_FLAG_SKIP_NH_OIF;
  39         memcpy(&fl6.daddr, daddr, sizeof(fl6.daddr));
  40         if (saddr)
  41                 memcpy(&fl6.saddr, saddr, sizeof(fl6.saddr));
  42
  43         dst = ip6_route_output(net, NULL, &fl6);
  44
  45         err = dst->error;
  46         if (dst->error) {
  47                 dst_release(dst);
  48                 dst = ERR_PTR(err);
  49         }
  50
  51         return dst;
  52 }
  53
  54 static int xfrm6_get_saddr(struct net *net, int oif,
  55                            xfrm_address_t *saddr, xfrm_address_t *daddr)
  56 {
  57         struct dst_entry *dst;
  58         struct net_device *dev;
  59
  60         dst = xfrm6_dst_lookup(net, 0, oif, NULL, daddr);
  61         if (IS_ERR(dst))
  62                 return -EHOSTUNREACH;
  63
  64         dev = ip6_dst_idev(dst)->dev;
  65         ipv6_dev_get_saddr(dev_net(dev), dev, &daddr->in6, 0, &saddr->in6);
  66         dst_release(dst);
  67         return 0;
  68 }
  69
  70 static int xfrm6_get_tos(const struct flowi *fl)
  71 {
  72         return 0;
  73 }
  74
  75 static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
  76                            int nfheader_len)
  77 {
  78         if (dst->ops->family == AF_INET6) {
  79                 struct rt6_info *rt = (struct rt6_info *)dst;
  80                 path->path_cookie = rt6_get_cookie(rt);
  81         }
  82
  83         path->u.rt6.rt6i_nfheader_len = nfheader_len;
  84
  85         return 0;
  86 }
  87
  88 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
  89                           const struct flowi *fl)
  90 {
  91         struct rt6_info *rt = (struct rt6_info *)xdst->route;
  92
  93         xdst->u.dst.dev = dev;
  94         dev_hold(dev);
  95
  96         xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
  97         if (!xdst->u.rt6.rt6i_idev) {
  98                 dev_put(dev);
  99                 return -ENODEV;
 100         }
 101
 102         /* Sheit... I remember I did this right. Apparently,
 103          * it was magically lost, so this code needs audit */
 104         xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
 105                                                    RTF_LOCAL);
 106         xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
 107         xdst->u.rt6.rt6i_node = rt->rt6i_node;
 108         xdst->route_cookie = rt6_get_cookie(rt);
 109         xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
 110         xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
 111         xdst->u.rt6.rt6i_src = rt->rt6i_src;
 112
 113         return 0;
 114 }
 115
 116 static inline void
 117 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
 118 {
 119         struct flowi6 *fl6 = &fl->u.ip6;
 120         int onlyproto = 0;
 121         const struct ipv6hdr *hdr = ipv6_hdr(skb);
 122         u16 offset = sizeof(*hdr);
 123         struct ipv6_opt_hdr *exthdr;
 124         const unsigned char *nh = skb_network_header(skb);
 125         u16 nhoff = IP6CB(skb)->nhoff;
 126         int oif = 0;
 127         u8 nexthdr;
 128
 129         if (!nhoff)
 130                 nhoff = offsetof(struct ipv6hdr, nexthdr);
 131
 132         nexthdr = nh[nhoff];
 133
 134         if (skb_dst(skb))
 135                 oif = skb_dst(skb)->dev->ifindex;
 136
 137         memset(fl6, 0, sizeof(struct flowi6));
 138         fl6->flowi6_mark = skb->mark;
 139         fl6->flowi6_oif = reverse ? skb->skb_iif : oif;
 140
 141         fl6->daddr = reverse ? hdr->saddr : hdr->daddr;
 142         fl6->saddr = reverse ? hdr->daddr : hdr->saddr;
 143
 144         while (nh + offset + 1 < skb->data ||
 145                pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
 146                 nh = skb_network_header(skb);
 147                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 148
 149                 switch (nexthdr) {
 150                 case NEXTHDR_FRAGMENT:
 151                         onlyproto = 1;
 152                 case NEXTHDR_ROUTING:
 153                 case NEXTHDR_HOP:
 154                 case NEXTHDR_DEST:
 155                         offset += ipv6_optlen(exthdr);
 156                         nexthdr = exthdr->nexthdr;
 157                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 158                         break;
 159
 160                 case IPPROTO_UDP:
 161                 case IPPROTO_UDPLITE:
 162                 case IPPROTO_TCP:
 163                 case IPPROTO_SCTP:
 164                 case IPPROTO_DCCP:
 165                         if (!onlyproto && (nh + offset + 4 < skb->data ||
 166                              pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
 167                                 __be16 *ports;
 168
 169                                 nh = skb_network_header(skb);
 170                                 ports = (__be16 *)(nh + offset);
 171                                 fl6->fl6_sport = ports[!!reverse];
 172                                 fl6->fl6_dport = ports[!reverse];
 173                         }
 174                         fl6->flowi6_proto = nexthdr;
 175                         return;
 176
 177                 case IPPROTO_ICMPV6:
 178                         if (!onlyproto && (nh + offset + 2 < skb->data ||
 179                             pskb_may_pull(skb, nh + offset + 2 - skb->data))) {
 180                                 u8 *icmp;
 181
 182                                 nh = skb_network_header(skb);
 183                                 icmp = (u8 *)(nh + offset);
 184                                 fl6->fl6_icmp_type = icmp[0];
 185                                 fl6->fl6_icmp_code = icmp[1];
 186                         }
 187                         fl6->flowi6_proto = nexthdr;
 188                         return;
 189
 190 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 191                 case IPPROTO_MH:
 192                         offset += ipv6_optlen(exthdr);
 193                         if (!onlyproto && (nh + offset + 3 < skb->data ||
 194                             pskb_may_pull(skb, nh + offset + 3 - skb->data))) {
 195                                 struct ip6_mh *mh;
 196
 197                                 nh = skb_network_header(skb);
 198                                 mh = (struct ip6_mh *)(nh + offset);
 199                                 fl6->fl6_mh_type = mh->ip6mh_type;
 200                         }
 201                         fl6->flowi6_proto = nexthdr;
 202                         return;
 203 #endif
 204
 205                 /* XXX Why are there these headers? */
 206                 case IPPROTO_AH:
 207                 case IPPROTO_ESP:
 208                 case IPPROTO_COMP:
 209                 default:
 210                         fl6->fl6_ipsec_spi = 0;
 211                         fl6->flowi6_proto = nexthdr;
 212                         return;
 213                 }
 214         }
 215 }
 216
 217 static inline int xfrm6_garbage_collect(struct dst_ops *ops)
 218 {
 219         struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
 220
 221         xfrm_garbage_collect_deferred(net);
 222         return dst_entries_get_fast(ops) > ops->gc_thresh * 2;
 223 }
 224
 225 static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk,
 226                               struct sk_buff *skb, u32 mtu)
 227 {
 228         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 229         struct dst_entry *path = xdst->route;
 230
 231         path->ops->update_pmtu(path, sk, skb, mtu);
 232 }
 233
 234 static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk,
 235                            struct sk_buff *skb)
 236 {
 237         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 238         struct dst_entry *path = xdst->route;
 239
 240         path->ops->redirect(path, sk, skb);
 241 }
 242
 243 static void xfrm6_dst_destroy(struct dst_entry *dst)
 244 {
 245         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 246
 247         if (likely(xdst->u.rt6.rt6i_idev))
 248                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 249         dst_destroy_metrics_generic(dst);
 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         .gc =                   xfrm6_garbage_collect,
 283         .update_pmtu =          xfrm6_update_pmtu,
 284         .redirect =             xfrm6_redirect,
 285         .cow_metrics =          dst_cow_metrics_generic,
 286         .destroy =              xfrm6_dst_destroy,
 287         .ifdown =               xfrm6_dst_ifdown,
 288         .local_out =            __ip6_local_out,
 289         .gc_thresh =            INT_MAX,
 290 };
 291
 292 static const struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 293         .dst_ops =              &xfrm6_dst_ops_template,
 294         .dst_lookup =           xfrm6_dst_lookup,
 295         .get_saddr =            xfrm6_get_saddr,
 296         .decode_session =       _decode_session6,
 297         .get_tos =              xfrm6_get_tos,
 298         .init_path =            xfrm6_init_path,
 299         .fill_dst =             xfrm6_fill_dst,
 300         .blackhole_route =      ip6_blackhole_route,
 301 };
 302
 303 static int __init xfrm6_policy_init(void)
 304 {
 305         return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo, AF_INET6);
 306 }
 307
 308 static void xfrm6_policy_fini(void)
 309 {
 310         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 311 }
 312
 313 #ifdef CONFIG_SYSCTL
 314 static struct ctl_table xfrm6_policy_table[] = {
 315         {
 316                 .procname       = "xfrm6_gc_thresh",
 317                 .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
 318                 .maxlen         = sizeof(int),
 319                 .mode           = 0644,
 320                 .proc_handler   = proc_dointvec,
 321         },
 322         { }
 323 };
 324
 325 static int __net_init xfrm6_net_sysctl_init(struct net *net)
 326 {
 327         struct ctl_table *table;
 328         struct ctl_table_header *hdr;
 329
 330         table = xfrm6_policy_table;
 331         if (!net_eq(net, &init_net)) {
 332                 table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL);
 333                 if (!table)
 334                         goto err_alloc;
 335
 336                 table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh;
 337         }
 338
 339         hdr = register_net_sysctl(net, "net/ipv6", table);
 340         if (!hdr)
 341                 goto err_reg;
 342
 343         net->ipv6.sysctl.xfrm6_hdr = hdr;
 344         return 0;
 345
 346 err_reg:
 347         if (!net_eq(net, &init_net))
 348                 kfree(table);
 349 err_alloc:
 350         return -ENOMEM;
 351 }
 352
 353 static void __net_exit xfrm6_net_sysctl_exit(struct net *net)
 354 {
 355         struct ctl_table *table;
 356
 357         if (!net->ipv6.sysctl.xfrm6_hdr)
 358                 return;
 359
 360         table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg;
 361         unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr);
 362         if (!net_eq(net, &init_net))
 363                 kfree(table);
 364 }
 365 #else /* CONFIG_SYSCTL */
 366 static inline int xfrm6_net_sysctl_init(struct net *net)
 367 {
 368         return 0;
 369 }
 370
 371 static inline void xfrm6_net_sysctl_exit(struct net *net)
 372 {
 373 }
 374 #endif
 375
 376 static int __net_init xfrm6_net_init(struct net *net)
 377 {
 378         int ret;
 379
 380         memcpy(&net->xfrm.xfrm6_dst_ops, &xfrm6_dst_ops_template,
 381                sizeof(xfrm6_dst_ops_template));
 382         ret = dst_entries_init(&net->xfrm.xfrm6_dst_ops);
 383         if (ret)
 384                 return ret;
 385
 386         ret = xfrm6_net_sysctl_init(net);
 387         if (ret)
 388                 dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
 389
 390         return ret;
 391 }
 392
 393 static void __net_exit xfrm6_net_exit(struct net *net)
 394 {
 395         xfrm6_net_sysctl_exit(net);
 396         dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
 397 }
 398
 399 static struct pernet_operations xfrm6_net_ops = {
 400         .init   = xfrm6_net_init,
 401         .exit   = xfrm6_net_exit,
 402 };
 403
 404 int __init xfrm6_init(void)
 405 {
 406         int ret;
 407
 408         ret = xfrm6_policy_init();
 409         if (ret)
 410                 goto out;
 411         ret = xfrm6_state_init();
 412         if (ret)
 413                 goto out_policy;
 414
 415         ret = xfrm6_protocol_init();
 416         if (ret)
 417                 goto out_state;
 418
 419         register_pernet_subsys(&xfrm6_net_ops);
 420 out:
 421         return ret;
 422 out_state:
 423         xfrm6_state_fini();
 424 out_policy:
 425         xfrm6_policy_fini();
 426         goto out;
 427 }
 428
 429 void xfrm6_fini(void)
 430 {
 431         unregister_pernet_subsys(&xfrm6_net_ops);
 432         xfrm6_protocol_fini();
 433         xfrm6_policy_fini();
 434         xfrm6_state_fini();
 435 }