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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/xfrm.h>
  18 #include <net/ip.h>
  19 #include <net/ipv6.h>
  20 #include <net/ip6_route.h>
  21 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
  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_TRANSPORT) {
 182                         unsigned short encap_family = xfrm[i]->props.family;
 183                         switch(encap_family) {
 184                         case AF_INET:
 185                                 fl_tunnel.fl4_dst = xfrm[i]->id.daddr.a4;
 186                                 fl_tunnel.fl4_src = xfrm[i]->props.saddr.a4;
 187                                 break;
 188                         case AF_INET6:
 189                                 ipv6_addr_copy(&fl_tunnel.fl6_dst, __xfrm6_bundle_addr_remote(xfrm[i], &fl->fl6_dst));
 190
 191                                 ipv6_addr_copy(&fl_tunnel.fl6_src, __xfrm6_bundle_addr_local(xfrm[i], &fl->fl6_src));
 192                                 break;
 193                         default:
 194                                 BUG_ON(1);
 195                         }
 196
 197                         err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
 198                                               &fl_tunnel, encap_family);
 199                         if (err)
 200                                 goto error;
 201                 } else
 202                         dst_hold(&rt->u.dst);
 203         }
 204
 205         dst_prev->child = &rt->u.dst;
 206         dst->path = &rt->u.dst;
 207         if (rt->rt6i_node)
 208                 ((struct xfrm_dst *)dst)->path_cookie = rt->rt6i_node->fn_sernum;
 209
 210         *dst_p = dst;
 211         dst = dst_prev;
 212
 213         dst_prev = *dst_p;
 214         i = 0;
 215         for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
 216                 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
 217                 struct xfrm_state_afinfo *afinfo;
 218
 219                 dst_prev->xfrm = xfrm[i++];
 220                 dst_prev->dev = rt->u.dst.dev;
 221                 if (rt->u.dst.dev)
 222                         dev_hold(rt->u.dst.dev);
 223                 dst_prev->obsolete      = -1;
 224                 dst_prev->flags        |= DST_HOST;
 225                 dst_prev->lastuse       = jiffies;
 226                 dst_prev->header_len    = header_len;
 227                 dst_prev->nfheader_len  = nfheader_len;
 228                 dst_prev->trailer_len   = trailer_len;
 229                 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
 230
 231                 /* Copy neighbour for reachability confirmation */
 232                 dst_prev->neighbour     = neigh_clone(rt->u.dst.neighbour);
 233                 dst_prev->input         = rt->u.dst.input;
 234                 /* XXX: When IPv4 is implemented as module and can be unloaded,
 235                  * we should manage reference to xfrm4_output in afinfo->output.
 236                  * Miyazawa
 237                  */
 238                 afinfo = xfrm_state_get_afinfo(dst_prev->xfrm->props.family);
 239                 if (!afinfo) {
 240                         dst = *dst_p;
 241                         goto error;
 242                 }
 243
 244                 dst_prev->output = afinfo->output;
 245                 xfrm_state_put_afinfo(afinfo);
 246                 /* Sheit... I remember I did this right. Apparently,
 247                  * it was magically lost, so this code needs audit */
 248                 x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
 249                 x->u.rt6.rt6i_metric   = rt0->rt6i_metric;
 250                 x->u.rt6.rt6i_node     = rt0->rt6i_node;
 251                 x->u.rt6.rt6i_gateway  = rt0->rt6i_gateway;
 252                 memcpy(&x->u.rt6.rt6i_gateway, &rt0->rt6i_gateway, sizeof(x->u.rt6.rt6i_gateway));
 253                 x->u.rt6.rt6i_dst      = rt0->rt6i_dst;
 254                 x->u.rt6.rt6i_src      = rt0->rt6i_src;
 255                 x->u.rt6.rt6i_idev     = rt0->rt6i_idev;
 256                 in6_dev_hold(rt0->rt6i_idev);
 257                 __xfrm6_bundle_len_dec(&header_len, &nfheader_len, x->u.dst.xfrm);
 258                 trailer_len -= x->u.dst.xfrm->props.trailer_len;
 259         }
 260
 261         xfrm_init_pmtu(dst);
 262         return 0;
 263
 264 error:
 265         if (dst)
 266                 dst_free(dst);
 267         return err;
 268 }
 269
 270 static inline void
 271 _decode_session6(struct sk_buff *skb, struct flowi *fl)
 272 {
 273         u16 offset = skb_network_header_len(skb);
 274         struct ipv6hdr *hdr = ipv6_hdr(skb);
 275         struct ipv6_opt_hdr *exthdr;
 276         const unsigned char *nh = skb_network_header(skb);
 277         u8 nexthdr = nh[IP6CB(skb)->nhoff];
 278
 279         memset(fl, 0, sizeof(struct flowi));
 280         ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
 281         ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
 282
 283         while (pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
 284                 nh = skb_network_header(skb);
 285                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 286
 287                 switch (nexthdr) {
 288                 case NEXTHDR_ROUTING:
 289                 case NEXTHDR_HOP:
 290                 case NEXTHDR_DEST:
 291                         offset += ipv6_optlen(exthdr);
 292                         nexthdr = exthdr->nexthdr;
 293                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 294                         break;
 295
 296                 case IPPROTO_UDP:
 297                 case IPPROTO_UDPLITE:
 298                 case IPPROTO_TCP:
 299                 case IPPROTO_SCTP:
 300                 case IPPROTO_DCCP:
 301                         if (pskb_may_pull(skb, nh + offset + 4 - skb->data)) {
 302                                 __be16 *ports = (__be16 *)exthdr;
 303
 304                                 fl->fl_ip_sport = ports[0];
 305                                 fl->fl_ip_dport = ports[1];
 306                         }
 307                         fl->proto = nexthdr;
 308                         return;
 309
 310                 case IPPROTO_ICMPV6:
 311                         if (pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
 312                                 u8 *icmp = (u8 *)exthdr;
 313
 314                                 fl->fl_icmp_type = icmp[0];
 315                                 fl->fl_icmp_code = icmp[1];
 316                         }
 317                         fl->proto = nexthdr;
 318                         return;
 319
 320 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 321                 case IPPROTO_MH:
 322                         if (pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
 323                                 struct ip6_mh *mh;
 324                                 mh = (struct ip6_mh *)exthdr;
 325
 326                                 fl->fl_mh_type = mh->ip6mh_type;
 327                         }
 328                         fl->proto = nexthdr;
 329                         return;
 330 #endif
 331
 332                 /* XXX Why are there these headers? */
 333                 case IPPROTO_AH:
 334                 case IPPROTO_ESP:
 335                 case IPPROTO_COMP:
 336                 default:
 337                         fl->fl_ipsec_spi = 0;
 338                         fl->proto = nexthdr;
 339                         return;
 340                 }
 341         }
 342 }
 343
 344 static inline int xfrm6_garbage_collect(void)
 345 {
 346         xfrm6_policy_afinfo.garbage_collect();
 347         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
 348 }
 349
 350 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 351 {
 352         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 353         struct dst_entry *path = xdst->route;
 354
 355         path->ops->update_pmtu(path, mtu);
 356 }
 357
 358 static void xfrm6_dst_destroy(struct dst_entry *dst)
 359 {
 360         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 361
 362         if (likely(xdst->u.rt6.rt6i_idev))
 363                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 364         xfrm_dst_destroy(xdst);
 365 }
 366
 367 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 368                              int unregister)
 369 {
 370         struct xfrm_dst *xdst;
 371
 372         if (!unregister)
 373                 return;
 374
 375         xdst = (struct xfrm_dst *)dst;
 376         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 377                 struct inet6_dev *loopback_idev = in6_dev_get(init_net.loopback_dev);
 378                 BUG_ON(!loopback_idev);
 379
 380                 do {
 381                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 382                         xdst->u.rt6.rt6i_idev = loopback_idev;
 383                         in6_dev_hold(loopback_idev);
 384                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 385                 } while (xdst->u.dst.xfrm);
 386
 387                 __in6_dev_put(loopback_idev);
 388         }
 389
 390         xfrm_dst_ifdown(dst, dev);
 391 }
 392
 393 static struct dst_ops xfrm6_dst_ops = {
 394         .family =               AF_INET6,
 395         .protocol =             __constant_htons(ETH_P_IPV6),
 396         .gc =                   xfrm6_garbage_collect,
 397         .update_pmtu =          xfrm6_update_pmtu,
 398         .destroy =              xfrm6_dst_destroy,
 399         .ifdown =               xfrm6_dst_ifdown,
 400         .gc_thresh =            1024,
 401         .entry_size =           sizeof(struct xfrm_dst),
 402 };
 403
 404 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 405         .family =               AF_INET6,
 406         .dst_ops =              &xfrm6_dst_ops,
 407         .dst_lookup =           xfrm6_dst_lookup,
 408         .get_saddr =            xfrm6_get_saddr,
 409         .find_bundle =          __xfrm6_find_bundle,
 410         .bundle_create =        __xfrm6_bundle_create,
 411         .decode_session =       _decode_session6,
 412 };
 413
 414 static void __init xfrm6_policy_init(void)
 415 {
 416         xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 417 }
 418
 419 static void xfrm6_policy_fini(void)
 420 {
 421         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 422 }
 423
 424 void __init xfrm6_init(void)
 425 {
 426         xfrm6_policy_init();
 427         xfrm6_state_init();
 428 }
 429
 430 void xfrm6_fini(void)
 431 {
 432         //xfrm6_input_fini();
 433         xfrm6_policy_fini();
 434         xfrm6_state_fini();
 435 }