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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 #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 in6_addr *remote = &fl->fl6_dst;
 135         struct in6_addr *local  = &fl->fl6_src;
 136         struct flowi fl_tunnel = {
 137                 .nl_u = {
 138                         .ip6_u = {
 139                                 .saddr = *local,
 140                                 .daddr = *remote
 141                         }
 142                 }
 143         };
 144         int i;
 145         int err = 0;
 146         int header_len = 0;
 147         int nfheader_len = 0;
 148         int trailer_len = 0;
 149
 150         dst = dst_prev = NULL;
 151         dst_hold(&rt->u.dst);
 152
 153         for (i = 0; i < nx; i++) {
 154                 struct dst_entry *dst1 = dst_alloc(&xfrm6_dst_ops);
 155                 struct xfrm_dst *xdst;
 156                 int tunnel = 0;
 157
 158                 if (unlikely(dst1 == NULL)) {
 159                         err = -ENOBUFS;
 160                         dst_release(&rt->u.dst);
 161                         goto error;
 162                 }
 163
 164                 if (!dst)
 165                         dst = dst1;
 166                 else {
 167                         dst_prev->child = dst1;
 168                         dst1->flags |= DST_NOHASH;
 169                         dst_clone(dst1);
 170                 }
 171
 172                 xdst = (struct xfrm_dst *)dst1;
 173                 xdst->route = &rt->u.dst;
 174                 xdst->genid = xfrm[i]->genid;
 175                 if (rt->rt6i_node)
 176                         xdst->route_cookie = rt->rt6i_node->fn_sernum;
 177
 178                 dst1->next = dst_prev;
 179                 dst_prev = dst1;
 180                 if (xfrm[i]->props.mode != XFRM_MODE_TRANSPORT) {
 181                         remote = __xfrm6_bundle_addr_remote(xfrm[i], remote);
 182                         local  = __xfrm6_bundle_addr_local(xfrm[i], local);
 183                         tunnel = 1;
 184                 }
 185                 __xfrm6_bundle_len_inc(&header_len, &nfheader_len, xfrm[i]);
 186                 trailer_len += xfrm[i]->props.trailer_len;
 187
 188                 if (tunnel) {
 189                         ipv6_addr_copy(&fl_tunnel.fl6_dst, remote);
 190                         ipv6_addr_copy(&fl_tunnel.fl6_src, local);
 191                         err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
 192                                               &fl_tunnel, AF_INET6);
 193                         if (err)
 194                                 goto error;
 195                 } else
 196                         dst_hold(&rt->u.dst);
 197         }
 198
 199         dst_prev->child = &rt->u.dst;
 200         dst->path = &rt->u.dst;
 201         if (rt->rt6i_node)
 202                 ((struct xfrm_dst *)dst)->path_cookie = rt->rt6i_node->fn_sernum;
 203
 204         *dst_p = dst;
 205         dst = dst_prev;
 206
 207         dst_prev = *dst_p;
 208         i = 0;
 209         for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
 210                 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
 211
 212                 dst_prev->xfrm = xfrm[i++];
 213                 dst_prev->dev = rt->u.dst.dev;
 214                 if (rt->u.dst.dev)
 215                         dev_hold(rt->u.dst.dev);
 216                 dst_prev->obsolete      = -1;
 217                 dst_prev->flags        |= DST_HOST;
 218                 dst_prev->lastuse       = jiffies;
 219                 dst_prev->header_len    = header_len;
 220                 dst_prev->nfheader_len  = nfheader_len;
 221                 dst_prev->trailer_len   = trailer_len;
 222                 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
 223
 224                 /* Copy neighbour for reachability confirmation */
 225                 dst_prev->neighbour     = neigh_clone(rt->u.dst.neighbour);
 226                 dst_prev->input         = rt->u.dst.input;
 227                 dst_prev->output        = xfrm6_output;
 228                 /* Sheit... I remember I did this right. Apparently,
 229                  * it was magically lost, so this code needs audit */
 230                 x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
 231                 x->u.rt6.rt6i_metric   = rt0->rt6i_metric;
 232                 x->u.rt6.rt6i_node     = rt0->rt6i_node;
 233                 x->u.rt6.rt6i_gateway  = rt0->rt6i_gateway;
 234                 memcpy(&x->u.rt6.rt6i_gateway, &rt0->rt6i_gateway, sizeof(x->u.rt6.rt6i_gateway));
 235                 x->u.rt6.rt6i_dst      = rt0->rt6i_dst;
 236                 x->u.rt6.rt6i_src      = rt0->rt6i_src;
 237                 x->u.rt6.rt6i_idev     = rt0->rt6i_idev;
 238                 in6_dev_hold(rt0->rt6i_idev);
 239                 __xfrm6_bundle_len_dec(&header_len, &nfheader_len, x->u.dst.xfrm);
 240                 trailer_len -= x->u.dst.xfrm->props.trailer_len;
 241         }
 242
 243         xfrm_init_pmtu(dst);
 244         return 0;
 245
 246 error:
 247         if (dst)
 248                 dst_free(dst);
 249         return err;
 250 }
 251
 252 static inline void
 253 _decode_session6(struct sk_buff *skb, struct flowi *fl)
 254 {
 255         u16 offset = skb->h.raw - skb->nh.raw;
 256         struct ipv6hdr *hdr = skb->nh.ipv6h;
 257         struct ipv6_opt_hdr *exthdr;
 258         u8 nexthdr = skb->nh.raw[IP6CB(skb)->nhoff];
 259
 260         memset(fl, 0, sizeof(struct flowi));
 261         ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
 262         ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
 263
 264         while (pskb_may_pull(skb, skb->nh.raw + offset + 1 - skb->data)) {
 265                 exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 266
 267                 switch (nexthdr) {
 268                 case NEXTHDR_ROUTING:
 269                 case NEXTHDR_HOP:
 270                 case NEXTHDR_DEST:
 271                         offset += ipv6_optlen(exthdr);
 272                         nexthdr = exthdr->nexthdr;
 273                         exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 274                         break;
 275
 276                 case IPPROTO_UDP:
 277                 case IPPROTO_UDPLITE:
 278                 case IPPROTO_TCP:
 279                 case IPPROTO_SCTP:
 280                 case IPPROTO_DCCP:
 281                         if (pskb_may_pull(skb, skb->nh.raw + offset + 4 - skb->data)) {
 282                                 __be16 *ports = (__be16 *)exthdr;
 283
 284                                 fl->fl_ip_sport = ports[0];
 285                                 fl->fl_ip_dport = ports[1];
 286                         }
 287                         fl->proto = nexthdr;
 288                         return;
 289
 290                 case IPPROTO_ICMPV6:
 291                         if (pskb_may_pull(skb, skb->nh.raw + offset + 2 - skb->data)) {
 292                                 u8 *icmp = (u8 *)exthdr;
 293
 294                                 fl->fl_icmp_type = icmp[0];
 295                                 fl->fl_icmp_code = icmp[1];
 296                         }
 297                         fl->proto = nexthdr;
 298                         return;
 299
 300 #ifdef CONFIG_IPV6_MIP6
 301                 case IPPROTO_MH:
 302                         if (pskb_may_pull(skb, skb->nh.raw + offset + 3 - skb->data)) {
 303                                 struct ip6_mh *mh;
 304                                 mh = (struct ip6_mh *)exthdr;
 305
 306                                 fl->fl_mh_type = mh->ip6mh_type;
 307                         }
 308                         fl->proto = nexthdr;
 309                         return;
 310 #endif
 311
 312                 /* XXX Why are there these headers? */
 313                 case IPPROTO_AH:
 314                 case IPPROTO_ESP:
 315                 case IPPROTO_COMP:
 316                 default:
 317                         fl->fl_ipsec_spi = 0;
 318                         fl->proto = nexthdr;
 319                         return;
 320                 };
 321         }
 322 }
 323
 324 static inline int xfrm6_garbage_collect(void)
 325 {
 326         xfrm6_policy_afinfo.garbage_collect();
 327         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
 328 }
 329
 330 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 331 {
 332         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 333         struct dst_entry *path = xdst->route;
 334
 335         path->ops->update_pmtu(path, mtu);
 336 }
 337
 338 static void xfrm6_dst_destroy(struct dst_entry *dst)
 339 {
 340         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 341
 342         if (likely(xdst->u.rt6.rt6i_idev))
 343                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 344         xfrm_dst_destroy(xdst);
 345 }
 346
 347 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 348                              int unregister)
 349 {
 350         struct xfrm_dst *xdst;
 351
 352         if (!unregister)
 353                 return;
 354
 355         xdst = (struct xfrm_dst *)dst;
 356         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 357                 struct inet6_dev *loopback_idev = in6_dev_get(&loopback_dev);
 358                 BUG_ON(!loopback_idev);
 359
 360                 do {
 361                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 362                         xdst->u.rt6.rt6i_idev = loopback_idev;
 363                         in6_dev_hold(loopback_idev);
 364                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 365                 } while (xdst->u.dst.xfrm);
 366
 367                 __in6_dev_put(loopback_idev);
 368         }
 369
 370         xfrm_dst_ifdown(dst, dev);
 371 }
 372
 373 static struct dst_ops xfrm6_dst_ops = {
 374         .family =               AF_INET6,
 375         .protocol =             __constant_htons(ETH_P_IPV6),
 376         .gc =                   xfrm6_garbage_collect,
 377         .update_pmtu =          xfrm6_update_pmtu,
 378         .destroy =              xfrm6_dst_destroy,
 379         .ifdown =               xfrm6_dst_ifdown,
 380         .gc_thresh =            1024,
 381         .entry_size =           sizeof(struct xfrm_dst),
 382 };
 383
 384 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 385         .family =               AF_INET6,
 386         .dst_ops =              &xfrm6_dst_ops,
 387         .dst_lookup =           xfrm6_dst_lookup,
 388         .get_saddr =            xfrm6_get_saddr,
 389         .find_bundle =          __xfrm6_find_bundle,
 390         .bundle_create =        __xfrm6_bundle_create,
 391         .decode_session =       _decode_session6,
 392 };
 393
 394 static void __init xfrm6_policy_init(void)
 395 {
 396         xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 397 }
 398
 399 static void xfrm6_policy_fini(void)
 400 {
 401         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 402 }
 403
 404 void __init xfrm6_init(void)
 405 {
 406         xfrm6_policy_init();
 407         xfrm6_state_init();
 408 }
 409
 410 void xfrm6_fini(void)
 411 {
 412         //xfrm6_input_fini();
 413         xfrm6_policy_fini();
 414         xfrm6_state_fini();
 415 }