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/dst.h>
  18 #include <net/xfrm.h>
  19 #include <net/ip.h>
  20 #include <net/ipv6.h>
  21 #include <net/ip6_route.h>
  22 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
  23 #include <net/mip6.h>
  24 #endif
  25
  26 static struct dst_ops xfrm6_dst_ops;
  27 static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
  28
  29 static int xfrm6_dst_lookup(struct xfrm_dst **xdst, struct flowi *fl)
  30 {
  31         struct dst_entry *dst = ip6_route_output(NULL, fl);
  32         int err = dst->error;
  33         if (!err)
  34                 *xdst = (struct xfrm_dst *) dst;
  35         else
  36                 dst_release(dst);
  37         return err;
  38 }
  39
  40 static int xfrm6_get_saddr(xfrm_address_t *saddr, xfrm_address_t *daddr)
  41 {
  42         struct rt6_info *rt;
  43         struct flowi fl_tunnel = {
  44                 .nl_u = {
  45                         .ip6_u = {
  46                                 .daddr = *(struct in6_addr *)&daddr->a6,
  47                         },
  48                 },
  49         };
  50
  51         if (!xfrm6_dst_lookup((struct xfrm_dst **)&rt, &fl_tunnel)) {
  52                 ipv6_get_saddr(&rt->u.dst, (struct in6_addr *)&daddr->a6,
  53                                (struct in6_addr *)&saddr->a6);
  54                 dst_release(&rt->u.dst);
  55                 return 0;
  56         }
  57         return -EHOSTUNREACH;
  58 }
  59
  60 static struct dst_entry *
  61 __xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
  62 {
  63         struct dst_entry *dst;
  64
  65         /* Still not clear if we should set fl->fl6_{src,dst}... */
  66         read_lock_bh(&policy->lock);
  67         for (dst = policy->bundles; dst; dst = dst->next) {
  68                 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
  69                 struct in6_addr fl_dst_prefix, fl_src_prefix;
  70
  71                 ipv6_addr_prefix(&fl_dst_prefix,
  72                                  &fl->fl6_dst,
  73                                  xdst->u.rt6.rt6i_dst.plen);
  74                 ipv6_addr_prefix(&fl_src_prefix,
  75                                  &fl->fl6_src,
  76                                  xdst->u.rt6.rt6i_src.plen);
  77                 if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
  78                     ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
  79                     xfrm_bundle_ok(policy, xdst, fl, AF_INET6,
  80                                    (xdst->u.rt6.rt6i_dst.plen != 128 ||
  81                                     xdst->u.rt6.rt6i_src.plen != 128))) {
  82                         dst_clone(dst);
  83                         break;
  84                 }
  85         }
  86         read_unlock_bh(&policy->lock);
  87         return dst;
  88 }
  89
  90 static inline struct in6_addr*
  91 __xfrm6_bundle_addr_remote(struct xfrm_state *x, struct in6_addr *addr)
  92 {
  93         return (x->type->remote_addr) ?
  94                 (struct in6_addr*)x->type->remote_addr(x, (xfrm_address_t *)addr) :
  95                 (struct in6_addr*)&x->id.daddr;
  96 }
  97
  98 static inline struct in6_addr*
  99 __xfrm6_bundle_addr_local(struct xfrm_state *x, struct in6_addr *addr)
 100 {
 101         return (x->type->local_addr) ?
 102                 (struct in6_addr*)x->type->local_addr(x, (xfrm_address_t *)addr) :
 103                 (struct in6_addr*)&x->props.saddr;
 104 }
 105
 106 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
 107  * all the metrics... Shortly, bundle a bundle.
 108  */
 109
 110 static int
 111 __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
 112                       struct flowi *fl, struct dst_entry **dst_p)
 113 {
 114         struct dst_entry *dst, *dst_prev;
 115         struct rt6_info *rt0 = (struct rt6_info*)(*dst_p);
 116         struct rt6_info *rt  = rt0;
 117         struct flowi fl_tunnel = {
 118                 .nl_u = {
 119                         .ip6_u = {
 120                                 .saddr = fl->fl6_src,
 121                                 .daddr = fl->fl6_dst,
 122                         }
 123                 }
 124         };
 125         int i;
 126         int err;
 127         int header_len = 0;
 128         int trailer_len = 0;
 129
 130         dst = dst_prev = NULL;
 131         dst_hold(&rt->u.dst);
 132
 133         for (i = 0; i < nx; i++) {
 134                 struct dst_entry *dst1 = dst_alloc(&xfrm6_dst_ops);
 135                 struct xfrm_dst *xdst;
 136
 137                 if (unlikely(dst1 == NULL)) {
 138                         err = -ENOBUFS;
 139                         dst_release(&rt->u.dst);
 140                         goto error;
 141                 }
 142
 143                 if (!dst)
 144                         dst = dst1;
 145                 else {
 146                         dst_prev->child = dst1;
 147                         dst1->flags |= DST_NOHASH;
 148                         dst_clone(dst1);
 149                 }
 150
 151                 xdst = (struct xfrm_dst *)dst1;
 152                 xdst->route = &rt->u.dst;
 153                 xdst->genid = xfrm[i]->genid;
 154                 if (rt->rt6i_node)
 155                         xdst->route_cookie = rt->rt6i_node->fn_sernum;
 156
 157                 dst1->next = dst_prev;
 158                 dst_prev = dst1;
 159
 160                 if (xfrm[i]->type->flags & XFRM_TYPE_NON_FRAGMENT)
 161                         ((struct rt6_info *)dst)->nfheader_len +=
 162                                 xfrm[i]->props.header_len;
 163                 header_len += xfrm[i]->props.header_len;
 164                 trailer_len += xfrm[i]->props.trailer_len;
 165
 166                 if (xfrm[i]->props.mode != XFRM_MODE_TRANSPORT) {
 167                         unsigned short encap_family = xfrm[i]->props.family;
 168                         switch(encap_family) {
 169                         case AF_INET:
 170                                 fl_tunnel.fl4_dst = xfrm[i]->id.daddr.a4;
 171                                 fl_tunnel.fl4_src = xfrm[i]->props.saddr.a4;
 172                                 break;
 173                         case AF_INET6:
 174                                 ipv6_addr_copy(&fl_tunnel.fl6_dst, __xfrm6_bundle_addr_remote(xfrm[i], &fl->fl6_dst));
 175
 176                                 ipv6_addr_copy(&fl_tunnel.fl6_src, __xfrm6_bundle_addr_local(xfrm[i], &fl->fl6_src));
 177                                 break;
 178                         default:
 179                                 BUG_ON(1);
 180                         }
 181
 182                         err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
 183                                               &fl_tunnel, encap_family);
 184                         if (err)
 185                                 goto error;
 186                 } else
 187                         dst_hold(&rt->u.dst);
 188         }
 189
 190         dst_prev->child = &rt->u.dst;
 191         dst->path = &rt->u.dst;
 192
 193         /* Copy neighbour for reachability confirmation */
 194         dst->neighbour = neigh_clone(rt->u.dst.neighbour);
 195
 196         if (rt->rt6i_node)
 197                 ((struct xfrm_dst *)dst)->path_cookie = rt->rt6i_node->fn_sernum;
 198
 199         *dst_p = dst;
 200         dst = dst_prev;
 201
 202         dst_prev = *dst_p;
 203         i = 0;
 204         err = -ENODEV;
 205         for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
 206                 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
 207
 208                 dst_prev->xfrm = xfrm[i++];
 209                 dst_prev->dev = rt->u.dst.dev;
 210                 if (!rt->u.dst.dev)
 211                         goto error;
 212                 dev_hold(rt->u.dst.dev);
 213
 214                 x->u.rt6.rt6i_idev = in6_dev_get(rt->u.dst.dev);
 215                 if (!x->u.rt6.rt6i_idev)
 216                         goto error;
 217
 218                 dst_prev->obsolete      = -1;
 219                 dst_prev->flags        |= DST_HOST;
 220                 dst_prev->lastuse       = jiffies;
 221                 dst_prev->header_len    = header_len;
 222                 dst_prev->trailer_len   = trailer_len;
 223                 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
 224
 225                 dst_prev->input = dst_discard;
 226                 dst_prev->output = dst_prev->xfrm->outer_mode->afinfo->output;
 227                 /* Sheit... I remember I did this right. Apparently,
 228                  * it was magically lost, so this code needs audit */
 229                 x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTF_ANYCAST|RTF_LOCAL);
 230                 x->u.rt6.rt6i_metric   = rt0->rt6i_metric;
 231                 x->u.rt6.rt6i_node     = rt0->rt6i_node;
 232                 x->u.rt6.rt6i_gateway  = rt0->rt6i_gateway;
 233                 memcpy(&x->u.rt6.rt6i_gateway, &rt0->rt6i_gateway, sizeof(x->u.rt6.rt6i_gateway));
 234                 x->u.rt6.rt6i_dst      = rt0->rt6i_dst;
 235                 x->u.rt6.rt6i_src      = rt0->rt6i_src;
 236                 header_len -= x->u.dst.xfrm->props.header_len;
 237                 trailer_len -= x->u.dst.xfrm->props.trailer_len;
 238         }
 239
 240         xfrm_init_pmtu(dst);
 241         return 0;
 242
 243 error:
 244         if (dst)
 245                 dst_free(dst);
 246         return err;
 247 }
 248
 249 static inline void
 250 _decode_session6(struct sk_buff *skb, struct flowi *fl)
 251 {
 252         u16 offset = skb_network_header_len(skb);
 253         struct ipv6hdr *hdr = ipv6_hdr(skb);
 254         struct ipv6_opt_hdr *exthdr;
 255         const unsigned char *nh = skb_network_header(skb);
 256         u8 nexthdr = nh[IP6CB(skb)->nhoff];
 257
 258         memset(fl, 0, sizeof(struct flowi));
 259         ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
 260         ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
 261
 262         while (pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
 263                 nh = skb_network_header(skb);
 264                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 265
 266                 switch (nexthdr) {
 267                 case NEXTHDR_ROUTING:
 268                 case NEXTHDR_HOP:
 269                 case NEXTHDR_DEST:
 270                         offset += ipv6_optlen(exthdr);
 271                         nexthdr = exthdr->nexthdr;
 272                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 273                         break;
 274
 275                 case IPPROTO_UDP:
 276                 case IPPROTO_UDPLITE:
 277                 case IPPROTO_TCP:
 278                 case IPPROTO_SCTP:
 279                 case IPPROTO_DCCP:
 280                         if (pskb_may_pull(skb, nh + offset + 4 - skb->data)) {
 281                                 __be16 *ports = (__be16 *)exthdr;
 282
 283                                 fl->fl_ip_sport = ports[0];
 284                                 fl->fl_ip_dport = ports[1];
 285                         }
 286                         fl->proto = nexthdr;
 287                         return;
 288
 289                 case IPPROTO_ICMPV6:
 290                         if (pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
 291                                 u8 *icmp = (u8 *)exthdr;
 292
 293                                 fl->fl_icmp_type = icmp[0];
 294                                 fl->fl_icmp_code = icmp[1];
 295                         }
 296                         fl->proto = nexthdr;
 297                         return;
 298
 299 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 300                 case IPPROTO_MH:
 301                         if (pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
 302                                 struct ip6_mh *mh;
 303                                 mh = (struct ip6_mh *)exthdr;
 304
 305                                 fl->fl_mh_type = mh->ip6mh_type;
 306                         }
 307                         fl->proto = nexthdr;
 308                         return;
 309 #endif
 310
 311                 /* XXX Why are there these headers? */
 312                 case IPPROTO_AH:
 313                 case IPPROTO_ESP:
 314                 case IPPROTO_COMP:
 315                 default:
 316                         fl->fl_ipsec_spi = 0;
 317                         fl->proto = nexthdr;
 318                         return;
 319                 }
 320         }
 321 }
 322
 323 static inline int xfrm6_garbage_collect(void)
 324 {
 325         xfrm6_policy_afinfo.garbage_collect();
 326         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
 327 }
 328
 329 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 330 {
 331         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 332         struct dst_entry *path = xdst->route;
 333
 334         path->ops->update_pmtu(path, mtu);
 335 }
 336
 337 static void xfrm6_dst_destroy(struct dst_entry *dst)
 338 {
 339         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 340
 341         if (likely(xdst->u.rt6.rt6i_idev))
 342                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 343         xfrm_dst_destroy(xdst);
 344 }
 345
 346 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 347                              int unregister)
 348 {
 349         struct xfrm_dst *xdst;
 350
 351         if (!unregister)
 352                 return;
 353
 354         xdst = (struct xfrm_dst *)dst;
 355         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 356                 struct inet6_dev *loopback_idev = in6_dev_get(init_net.loopback_dev);
 357                 BUG_ON(!loopback_idev);
 358
 359                 do {
 360                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 361                         xdst->u.rt6.rt6i_idev = loopback_idev;
 362                         in6_dev_hold(loopback_idev);
 363                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 364                 } while (xdst->u.dst.xfrm);
 365
 366                 __in6_dev_put(loopback_idev);
 367         }
 368
 369         xfrm_dst_ifdown(dst, dev);
 370 }
 371
 372 static struct dst_ops xfrm6_dst_ops = {
 373         .family =               AF_INET6,
 374         .protocol =             __constant_htons(ETH_P_IPV6),
 375         .gc =                   xfrm6_garbage_collect,
 376         .update_pmtu =          xfrm6_update_pmtu,
 377         .destroy =              xfrm6_dst_destroy,
 378         .ifdown =               xfrm6_dst_ifdown,
 379         .gc_thresh =            1024,
 380         .entry_size =           sizeof(struct xfrm_dst),
 381 };
 382
 383 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 384         .family =               AF_INET6,
 385         .dst_ops =              &xfrm6_dst_ops,
 386         .dst_lookup =           xfrm6_dst_lookup,
 387         .get_saddr =            xfrm6_get_saddr,
 388         .find_bundle =          __xfrm6_find_bundle,
 389         .bundle_create =        __xfrm6_bundle_create,
 390         .decode_session =       _decode_session6,
 391 };
 392
 393 static void __init xfrm6_policy_init(void)
 394 {
 395         xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 396 }
 397
 398 static void xfrm6_policy_fini(void)
 399 {
 400         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 401 }
 402
 403 void __init xfrm6_init(void)
 404 {
 405         xfrm6_policy_init();
 406         xfrm6_state_init();
 407 }
 408
 409 void xfrm6_fini(void)
 410 {
 411         //xfrm6_input_fini();
 412         xfrm6_policy_fini();
 413         xfrm6_state_fini();
 414 }