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