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/compiler.h>
  15 #include <linux/netdevice.h>
  16 #include <net/addrconf.h>
  17 #include <net/xfrm.h>
  18 #include <net/ip.h>
  19 #include <net/ipv6.h>
  20 #include <net/ip6_route.h>
  21 #ifdef CONFIG_IPV6_MIP6
  22 #include <net/mip6.h>
  23 #endif
  24
  25 static struct dst_ops xfrm6_dst_ops;
  26 static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
  27
  28 static int xfrm6_dst_lookup(struct xfrm_dst **xdst, struct flowi *fl)
  29 {
  30         struct dst_entry *dst = ip6_route_output(NULL, fl);
  31         int err = dst->error;
  32         if (!err)
  33                 *xdst = (struct xfrm_dst *) dst;
  34         else
  35                 dst_release(dst);
  36         return err;
  37 }
  38
  39 static int xfrm6_get_saddr(xfrm_address_t *saddr, xfrm_address_t *daddr)
  40 {
  41         struct rt6_info *rt;
  42         struct flowi fl_tunnel = {
  43                 .nl_u = {
  44                         .ip6_u = {
  45                                 .daddr = *(struct in6_addr *)&daddr->a6,
  46                         },
  47                 },
  48         };
  49
  50         if (!xfrm6_dst_lookup((struct xfrm_dst **)&rt, &fl_tunnel)) {
  51                 ipv6_get_saddr(&rt->u.dst, (struct in6_addr *)&daddr->a6,
  52                                (struct in6_addr *)&saddr->a6);
  53                 dst_release(&rt->u.dst);
  54                 return 0;
  55         }
  56         return -EHOSTUNREACH;
  57 }
  58
  59 static struct dst_entry *
  60 __xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
  61 {
  62         struct dst_entry *dst;
  63
  64         /* Still not clear if we should set fl->fl6_{src,dst}... */
  65         read_lock_bh(&policy->lock);
  66         for (dst = policy->bundles; dst; dst = dst->next) {
  67                 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
  68                 struct in6_addr fl_dst_prefix, fl_src_prefix;
  69
  70                 ipv6_addr_prefix(&fl_dst_prefix,
  71                                  &fl->fl6_dst,
  72                                  xdst->u.rt6.rt6i_dst.plen);
  73                 ipv6_addr_prefix(&fl_src_prefix,
  74                                  &fl->fl6_src,
  75                                  xdst->u.rt6.rt6i_src.plen);
  76                 if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
  77                     ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
  78                     xfrm_bundle_ok(policy, xdst, fl, AF_INET6,
  79                                    (xdst->u.rt6.rt6i_dst.plen != 128 ||
  80                                     xdst->u.rt6.rt6i_src.plen != 128))) {
  81                         dst_clone(dst);
  82                         break;
  83                 }
  84         }
  85         read_unlock_bh(&policy->lock);
  86         return dst;
  87 }
  88
  89 static inline struct in6_addr*
  90 __xfrm6_bundle_addr_remote(struct xfrm_state *x, struct in6_addr *addr)
  91 {
  92         return (x->type->remote_addr) ?
  93                 (struct in6_addr*)x->type->remote_addr(x, (xfrm_address_t *)addr) :
  94                 (struct in6_addr*)&x->id.daddr;
  95 }
  96
  97 static inline struct in6_addr*
  98 __xfrm6_bundle_addr_local(struct xfrm_state *x, struct in6_addr *addr)
  99 {
 100         return (x->type->local_addr) ?
 101                 (struct in6_addr*)x->type->local_addr(x, (xfrm_address_t *)addr) :
 102                 (struct in6_addr*)&x->props.saddr;
 103 }
 104
 105 static inline void
 106 __xfrm6_bundle_len_inc(int *len, int *nflen, struct xfrm_state *x)
 107 {
 108         if (x->type->flags & XFRM_TYPE_NON_FRAGMENT)
 109                 *nflen += x->props.header_len;
 110         else
 111                 *len += x->props.header_len;
 112 }
 113
 114 static inline void
 115 __xfrm6_bundle_len_dec(int *len, int *nflen, struct xfrm_state *x)
 116 {
 117         if (x->type->flags & XFRM_TYPE_NON_FRAGMENT)
 118                 *nflen -= x->props.header_len;
 119         else
 120                 *len -= x->props.header_len;
 121 }
 122
 123 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
 124  * all the metrics... Shortly, bundle a bundle.
 125  */
 126
 127 static int
 128 __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
 129                       struct flowi *fl, struct dst_entry **dst_p)
 130 {
 131         struct dst_entry *dst, *dst_prev;
 132         struct rt6_info *rt0 = (struct rt6_info*)(*dst_p);
 133         struct rt6_info *rt  = rt0;
 134         struct flowi fl_tunnel = {
 135                 .nl_u = {
 136                         .ip6_u = {
 137                                 .saddr = fl->fl6_src,
 138                                 .daddr = fl->fl6_dst,
 139                         }
 140                 }
 141         };
 142         int i;
 143         int err = 0;
 144         int header_len = 0;
 145         int nfheader_len = 0;
 146         int trailer_len = 0;
 147
 148         dst = dst_prev = NULL;
 149         dst_hold(&rt->u.dst);
 150
 151         for (i = 0; i < nx; i++) {
 152                 struct dst_entry *dst1 = dst_alloc(&xfrm6_dst_ops);
 153                 struct xfrm_dst *xdst;
 154
 155                 if (unlikely(dst1 == NULL)) {
 156                         err = -ENOBUFS;
 157                         dst_release(&rt->u.dst);
 158                         goto error;
 159                 }
 160
 161                 if (!dst)
 162                         dst = dst1;
 163                 else {
 164                         dst_prev->child = dst1;
 165                         dst1->flags |= DST_NOHASH;
 166                         dst_clone(dst1);
 167                 }
 168
 169                 xdst = (struct xfrm_dst *)dst1;
 170                 xdst->route = &rt->u.dst;
 171                 xdst->genid = xfrm[i]->genid;
 172                 if (rt->rt6i_node)
 173                         xdst->route_cookie = rt->rt6i_node->fn_sernum;
 174
 175                 dst1->next = dst_prev;
 176                 dst_prev = dst1;
 177
 178                 __xfrm6_bundle_len_inc(&header_len, &nfheader_len, xfrm[i]);
 179                 trailer_len += xfrm[i]->props.trailer_len;
 180
 181                 if (xfrm[i]->props.mode == XFRM_MODE_TUNNEL ||
 182                     xfrm[i]->props.mode == XFRM_MODE_ROUTEOPTIMIZATION) {
 183                         unsigned short encap_family = xfrm[i]->props.family;
 184                         switch(encap_family) {
 185                         case AF_INET:
 186                                 fl_tunnel.fl4_dst = xfrm[i]->id.daddr.a4;
 187                                 fl_tunnel.fl4_src = xfrm[i]->props.saddr.a4;
 188                                 break;
 189                         case AF_INET6:
 190                                 ipv6_addr_copy(&fl_tunnel.fl6_dst, __xfrm6_bundle_addr_remote(xfrm[i], &fl->fl6_dst));
 191
 192                                 ipv6_addr_copy(&fl_tunnel.fl6_src, __xfrm6_bundle_addr_local(xfrm[i], &fl->fl6_src));
 193                                 break;
 194                         default:
 195                                 BUG_ON(1);
 196                         }
 197
 198                         err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
 199                                               &fl_tunnel, encap_family);
 200                         if (err)
 201                                 goto error;
 202                 } else
 203                         dst_hold(&rt->u.dst);
 204         }
 205
 206         dst_prev->child = &rt->u.dst;
 207         dst->path = &rt->u.dst;
 208         if (rt->rt6i_node)
 209                 ((struct xfrm_dst *)dst)->path_cookie = rt->rt6i_node->fn_sernum;
 210
 211         *dst_p = dst;
 212         dst = dst_prev;
 213
 214         dst_prev = *dst_p;
 215         i = 0;
 216         for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
 217                 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
 218                 struct xfrm_state_afinfo *afinfo;
 219
 220                 dst_prev->xfrm = xfrm[i++];
 221                 dst_prev->dev = rt->u.dst.dev;
 222                 if (rt->u.dst.dev)
 223                         dev_hold(rt->u.dst.dev);
 224                 dst_prev->obsolete      = -1;
 225                 dst_prev->flags        |= DST_HOST;
 226                 dst_prev->lastuse       = jiffies;
 227                 dst_prev->header_len    = header_len;
 228                 dst_prev->nfheader_len  = nfheader_len;
 229                 dst_prev->trailer_len   = trailer_len;
 230                 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
 231
 232                 /* Copy neighbour for reachability confirmation */
 233                 dst_prev->neighbour     = neigh_clone(rt->u.dst.neighbour);
 234                 dst_prev->input         = rt->u.dst.input;
 235                 /* XXX: When IPv4 is implemented as module and can be unloaded,
 236                  * we should manage reference to xfrm4_output in afinfo->output.
 237                  * Miyazawa
 238                  */
 239                 afinfo = xfrm_state_get_afinfo(dst_prev->xfrm->props.family);
 240                 if (!afinfo) {
 241                         dst = *dst_p;
 242                         goto error;
 243                 }
 244
 245                 dst_prev->output = afinfo->output;
 246                 xfrm_state_put_afinfo(afinfo);
 247                 /* Sheit... I remember I did this right. Apparently,
 248                  * it was magically lost, so this code needs audit */
 249                 x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
 250                 x->u.rt6.rt6i_metric   = rt0->rt6i_metric;
 251                 x->u.rt6.rt6i_node     = rt0->rt6i_node;
 252                 x->u.rt6.rt6i_gateway  = rt0->rt6i_gateway;
 253                 memcpy(&x->u.rt6.rt6i_gateway, &rt0->rt6i_gateway, sizeof(x->u.rt6.rt6i_gateway));
 254                 x->u.rt6.rt6i_dst      = rt0->rt6i_dst;
 255                 x->u.rt6.rt6i_src      = rt0->rt6i_src;
 256                 x->u.rt6.rt6i_idev     = rt0->rt6i_idev;
 257                 in6_dev_hold(rt0->rt6i_idev);
 258                 __xfrm6_bundle_len_dec(&header_len, &nfheader_len, x->u.dst.xfrm);
 259                 trailer_len -= x->u.dst.xfrm->props.trailer_len;
 260         }
 261
 262         xfrm_init_pmtu(dst);
 263         return 0;
 264
 265 error:
 266         if (dst)
 267                 dst_free(dst);
 268         return err;
 269 }
 270
 271 static inline void
 272 _decode_session6(struct sk_buff *skb, struct flowi *fl)
 273 {
 274         u16 offset = skb_network_header_len(skb);
 275         struct ipv6hdr *hdr = ipv6_hdr(skb);
 276         struct ipv6_opt_hdr *exthdr;
 277         const unsigned char *nh = skb_network_header(skb);
 278         u8 nexthdr = nh[IP6CB(skb)->nhoff];
 279
 280         memset(fl, 0, sizeof(struct flowi));
 281         ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
 282         ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
 283
 284         while (pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
 285                 nh = skb_network_header(skb);
 286                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 287
 288                 switch (nexthdr) {
 289                 case NEXTHDR_ROUTING:
 290                 case NEXTHDR_HOP:
 291                 case NEXTHDR_DEST:
 292                         offset += ipv6_optlen(exthdr);
 293                         nexthdr = exthdr->nexthdr;
 294                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 295                         break;
 296
 297                 case IPPROTO_UDP:
 298                 case IPPROTO_UDPLITE:
 299                 case IPPROTO_TCP:
 300                 case IPPROTO_SCTP:
 301                 case IPPROTO_DCCP:
 302                         if (pskb_may_pull(skb, nh + offset + 4 - skb->data)) {
 303                                 __be16 *ports = (__be16 *)exthdr;
 304
 305                                 fl->fl_ip_sport = ports[0];
 306                                 fl->fl_ip_dport = ports[1];
 307                         }
 308                         fl->proto = nexthdr;
 309                         return;
 310
 311                 case IPPROTO_ICMPV6:
 312                         if (pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
 313                                 u8 *icmp = (u8 *)exthdr;
 314
 315                                 fl->fl_icmp_type = icmp[0];
 316                                 fl->fl_icmp_code = icmp[1];
 317                         }
 318                         fl->proto = nexthdr;
 319                         return;
 320
 321 #ifdef CONFIG_IPV6_MIP6
 322                 case IPPROTO_MH:
 323                         if (pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
 324                                 struct ip6_mh *mh;
 325                                 mh = (struct ip6_mh *)exthdr;
 326
 327                                 fl->fl_mh_type = mh->ip6mh_type;
 328                         }
 329                         fl->proto = nexthdr;
 330                         return;
 331 #endif
 332
 333                 /* XXX Why are there these headers? */
 334                 case IPPROTO_AH:
 335                 case IPPROTO_ESP:
 336                 case IPPROTO_COMP:
 337                 default:
 338                         fl->fl_ipsec_spi = 0;
 339                         fl->proto = nexthdr;
 340                         return;
 341                 }
 342         }
 343 }
 344
 345 static inline int xfrm6_garbage_collect(void)
 346 {
 347         xfrm6_policy_afinfo.garbage_collect();
 348         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
 349 }
 350
 351 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 352 {
 353         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 354         struct dst_entry *path = xdst->route;
 355
 356         path->ops->update_pmtu(path, mtu);
 357 }
 358
 359 static void xfrm6_dst_destroy(struct dst_entry *dst)
 360 {
 361         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 362
 363         if (likely(xdst->u.rt6.rt6i_idev))
 364                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 365         xfrm_dst_destroy(xdst);
 366 }
 367
 368 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 369                              int unregister)
 370 {
 371         struct xfrm_dst *xdst;
 372
 373         if (!unregister)
 374                 return;
 375
 376         xdst = (struct xfrm_dst *)dst;
 377         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 378                 struct inet6_dev *loopback_idev = in6_dev_get(&loopback_dev);
 379                 BUG_ON(!loopback_idev);
 380
 381                 do {
 382                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 383                         xdst->u.rt6.rt6i_idev = loopback_idev;
 384                         in6_dev_hold(loopback_idev);
 385                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 386                 } while (xdst->u.dst.xfrm);
 387
 388                 __in6_dev_put(loopback_idev);
 389         }
 390
 391         xfrm_dst_ifdown(dst, dev);
 392 }
 393
 394 static struct dst_ops xfrm6_dst_ops = {
 395         .family =               AF_INET6,
 396         .protocol =             __constant_htons(ETH_P_IPV6),
 397         .gc =                   xfrm6_garbage_collect,
 398         .update_pmtu =          xfrm6_update_pmtu,
 399         .destroy =              xfrm6_dst_destroy,
 400         .ifdown =               xfrm6_dst_ifdown,
 401         .gc_thresh =            1024,
 402         .entry_size =           sizeof(struct xfrm_dst),
 403 };
 404
 405 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 406         .family =               AF_INET6,
 407         .dst_ops =              &xfrm6_dst_ops,
 408         .dst_lookup =           xfrm6_dst_lookup,
 409         .get_saddr =            xfrm6_get_saddr,
 410         .find_bundle =          __xfrm6_find_bundle,
 411         .bundle_create =        __xfrm6_bundle_create,
 412         .decode_session =       _decode_session6,
 413 };
 414
 415 static void __init xfrm6_policy_init(void)
 416 {
 417         xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 418 }
 419
 420 static void xfrm6_policy_fini(void)
 421 {
 422         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 423 }
 424
 425 void __init xfrm6_init(void)
 426 {
 427         xfrm6_policy_init();
 428         xfrm6_state_init();
 429 }
 430
 431 void xfrm6_fini(void)
 432 {
 433         //xfrm6_input_fini();
 434         xfrm6_policy_fini();
 435         xfrm6_state_fini();
 436 }