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 **dst, struct flowi *fl)
  29 {
  30         int err = 0;
  31         *dst = (struct xfrm_dst*)ip6_route_output(NULL, fl);
  32         if (!*dst)
  33                 err = -ENETUNREACH;
  34         return err;
  35 }
  36
  37 static int xfrm6_get_saddr(xfrm_address_t *saddr, xfrm_address_t *daddr)
  38 {
  39         struct rt6_info *rt;
  40         struct flowi fl_tunnel = {
  41                 .nl_u = {
  42                         .ip6_u = {
  43                                 .daddr = *(struct in6_addr *)&daddr->a6,
  44                         },
  45                 },
  46         };
  47
  48         if (!xfrm6_dst_lookup((struct xfrm_dst **)&rt, &fl_tunnel)) {
  49                 ipv6_get_saddr(&rt->u.dst, (struct in6_addr *)&daddr->a6,
  50                                (struct in6_addr *)&saddr->a6);
  51                 dst_release(&rt->u.dst);
  52                 return 0;
  53         }
  54         return -EHOSTUNREACH;
  55 }
  56
  57 static struct dst_entry *
  58 __xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
  59 {
  60         struct dst_entry *dst;
  61
  62         /* Still not clear if we should set fl->fl6_{src,dst}... */
  63         read_lock_bh(&policy->lock);
  64         for (dst = policy->bundles; dst; dst = dst->next) {
  65                 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
  66                 struct in6_addr fl_dst_prefix, fl_src_prefix;
  67
  68                 ipv6_addr_prefix(&fl_dst_prefix,
  69                                  &fl->fl6_dst,
  70                                  xdst->u.rt6.rt6i_dst.plen);
  71                 ipv6_addr_prefix(&fl_src_prefix,
  72                                  &fl->fl6_src,
  73                                  xdst->u.rt6.rt6i_src.plen);
  74                 if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
  75                     ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
  76                     xfrm_bundle_ok(xdst, fl, AF_INET6,
  77                                    (xdst->u.rt6.rt6i_dst.plen != 128 ||
  78                                     xdst->u.rt6.rt6i_src.plen != 128))) {
  79                         dst_clone(dst);
  80                         break;
  81                 }
  82         }
  83         read_unlock_bh(&policy->lock);
  84         return dst;
  85 }
  86
  87 static inline struct in6_addr*
  88 __xfrm6_bundle_addr_remote(struct xfrm_state *x, struct in6_addr *addr)
  89 {
  90         return (x->type->remote_addr) ?
  91                 (struct in6_addr*)x->type->remote_addr(x, (xfrm_address_t *)addr) :
  92                 (struct in6_addr*)&x->id.daddr;
  93 }
  94
  95 static inline struct in6_addr*
  96 __xfrm6_bundle_addr_local(struct xfrm_state *x, struct in6_addr *addr)
  97 {
  98         return (x->type->local_addr) ?
  99                 (struct in6_addr*)x->type->local_addr(x, (xfrm_address_t *)addr) :
 100                 (struct in6_addr*)&x->props.saddr;
 101 }
 102
 103 static inline void
 104 __xfrm6_bundle_len_inc(int *len, int *nflen, struct xfrm_state *x)
 105 {
 106         if (x->type->flags & XFRM_TYPE_NON_FRAGMENT)
 107                 *nflen += x->props.header_len;
 108         else
 109                 *len += x->props.header_len;
 110 }
 111
 112 static inline void
 113 __xfrm6_bundle_len_dec(int *len, int *nflen, struct xfrm_state *x)
 114 {
 115         if (x->type->flags & XFRM_TYPE_NON_FRAGMENT)
 116                 *nflen -= x->props.header_len;
 117         else
 118                 *len -= x->props.header_len;
 119 }
 120
 121 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
 122  * all the metrics... Shortly, bundle a bundle.
 123  */
 124
 125 static int
 126 __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
 127                       struct flowi *fl, struct dst_entry **dst_p)
 128 {
 129         struct dst_entry *dst, *dst_prev;
 130         struct rt6_info *rt0 = (struct rt6_info*)(*dst_p);
 131         struct rt6_info *rt  = rt0;
 132         struct in6_addr *remote = &fl->fl6_dst;
 133         struct in6_addr *local  = &fl->fl6_src;
 134         struct flowi fl_tunnel = {
 135                 .nl_u = {
 136                         .ip6_u = {
 137                                 .saddr = *local,
 138                                 .daddr = *remote
 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                 int tunnel = 0;
 155
 156                 if (unlikely(dst1 == NULL)) {
 157                         err = -ENOBUFS;
 158                         dst_release(&rt->u.dst);
 159                         goto error;
 160                 }
 161
 162                 if (!dst)
 163                         dst = dst1;
 164                 else {
 165                         dst_prev->child = dst1;
 166                         dst1->flags |= DST_NOHASH;
 167                         dst_clone(dst1);
 168                 }
 169
 170                 xdst = (struct xfrm_dst *)dst1;
 171                 xdst->route = &rt->u.dst;
 172                 xdst->genid = xfrm[i]->genid;
 173                 if (rt->rt6i_node)
 174                         xdst->route_cookie = rt->rt6i_node->fn_sernum;
 175
 176                 dst1->next = dst_prev;
 177                 dst_prev = dst1;
 178                 if (xfrm[i]->props.mode != XFRM_MODE_TRANSPORT) {
 179                         remote = __xfrm6_bundle_addr_remote(xfrm[i], remote);
 180                         local  = __xfrm6_bundle_addr_local(xfrm[i], local);
 181                         tunnel = 1;
 182                 }
 183                 __xfrm6_bundle_len_inc(&header_len, &nfheader_len, xfrm[i]);
 184                 trailer_len += xfrm[i]->props.trailer_len;
 185
 186                 if (tunnel) {
 187                         ipv6_addr_copy(&fl_tunnel.fl6_dst, remote);
 188                         ipv6_addr_copy(&fl_tunnel.fl6_src, local);
 189                         err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
 190                                               &fl_tunnel, AF_INET6);
 191                         if (err)
 192                                 goto error;
 193                 } else
 194                         dst_hold(&rt->u.dst);
 195         }
 196
 197         dst_prev->child = &rt->u.dst;
 198         dst->path = &rt->u.dst;
 199         if (rt->rt6i_node)
 200                 ((struct xfrm_dst *)dst)->path_cookie = rt->rt6i_node->fn_sernum;
 201
 202         *dst_p = dst;
 203         dst = dst_prev;
 204
 205         dst_prev = *dst_p;
 206         i = 0;
 207         for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
 208                 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
 209
 210                 dst_prev->xfrm = xfrm[i++];
 211                 dst_prev->dev = rt->u.dst.dev;
 212                 if (rt->u.dst.dev)
 213                         dev_hold(rt->u.dst.dev);
 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->nfheader_len  = nfheader_len;
 219                 dst_prev->trailer_len   = trailer_len;
 220                 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
 221
 222                 /* Copy neighbour for reachability confirmation */
 223                 dst_prev->neighbour     = neigh_clone(rt->u.dst.neighbour);
 224                 dst_prev->input         = rt->u.dst.input;
 225                 dst_prev->output        = xfrm6_output;
 226                 /* Sheit... I remember I did this right. Apparently,
 227                  * it was magically lost, so this code needs audit */
 228                 x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
 229                 x->u.rt6.rt6i_metric   = rt0->rt6i_metric;
 230                 x->u.rt6.rt6i_node     = rt0->rt6i_node;
 231                 x->u.rt6.rt6i_gateway  = rt0->rt6i_gateway;
 232                 memcpy(&x->u.rt6.rt6i_gateway, &rt0->rt6i_gateway, sizeof(x->u.rt6.rt6i_gateway));
 233                 x->u.rt6.rt6i_dst      = rt0->rt6i_dst;
 234                 x->u.rt6.rt6i_src      = rt0->rt6i_src;
 235                 x->u.rt6.rt6i_idev     = rt0->rt6i_idev;
 236                 in6_dev_hold(rt0->rt6i_idev);
 237                 __xfrm6_bundle_len_dec(&header_len, &nfheader_len, x->u.dst.xfrm);
 238                 trailer_len -= x->u.dst.xfrm->props.trailer_len;
 239         }
 240
 241         xfrm_init_pmtu(dst);
 242         return 0;
 243
 244 error:
 245         if (dst)
 246                 dst_free(dst);
 247         return err;
 248 }
 249
 250 static inline void
 251 _decode_session6(struct sk_buff *skb, struct flowi *fl)
 252 {
 253         u16 offset = skb->h.raw - skb->nh.raw;
 254         struct ipv6hdr *hdr = skb->nh.ipv6h;
 255         struct ipv6_opt_hdr *exthdr;
 256         u8 nexthdr = skb->nh.raw[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, skb->nh.raw + offset + 1 - skb->data)) {
 263                 exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 264
 265                 switch (nexthdr) {
 266                 case NEXTHDR_ROUTING:
 267                 case NEXTHDR_HOP:
 268                 case NEXTHDR_DEST:
 269                         offset += ipv6_optlen(exthdr);
 270                         nexthdr = exthdr->nexthdr;
 271                         exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 272                         break;
 273
 274                 case IPPROTO_UDP:
 275                 case IPPROTO_TCP:
 276                 case IPPROTO_SCTP:
 277                 case IPPROTO_DCCP:
 278                         if (pskb_may_pull(skb, skb->nh.raw + offset + 4 - skb->data)) {
 279                                 u16 *ports = (u16 *)exthdr;
 280
 281                                 fl->fl_ip_sport = ports[0];
 282                                 fl->fl_ip_dport = ports[1];
 283                         }
 284                         fl->proto = nexthdr;
 285                         return;
 286
 287                 case IPPROTO_ICMPV6:
 288                         if (pskb_may_pull(skb, skb->nh.raw + offset + 2 - skb->data)) {
 289                                 u8 *icmp = (u8 *)exthdr;
 290
 291                                 fl->fl_icmp_type = icmp[0];
 292                                 fl->fl_icmp_code = icmp[1];
 293                         }
 294                         fl->proto = nexthdr;
 295                         return;
 296
 297 #ifdef CONFIG_IPV6_MIP6
 298                 case IPPROTO_MH:
 299                         if (pskb_may_pull(skb, skb->nh.raw + offset + 3 - skb->data)) {
 300                                 struct ip6_mh *mh;
 301                                 mh = (struct ip6_mh *)exthdr;
 302
 303                                 fl->fl_mh_type = mh->ip6mh_type;
 304                         }
 305                         fl->proto = nexthdr;
 306                         return;
 307 #endif
 308
 309                 /* XXX Why are there these headers? */
 310                 case IPPROTO_AH:
 311                 case IPPROTO_ESP:
 312                 case IPPROTO_COMP:
 313                 default:
 314                         fl->fl_ipsec_spi = 0;
 315                         fl->proto = nexthdr;
 316                         return;
 317                 };
 318         }
 319 }
 320
 321 static inline int xfrm6_garbage_collect(void)
 322 {
 323         xfrm6_policy_afinfo.garbage_collect();
 324         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
 325 }
 326
 327 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 328 {
 329         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 330         struct dst_entry *path = xdst->route;
 331
 332         path->ops->update_pmtu(path, mtu);
 333 }
 334
 335 static void xfrm6_dst_destroy(struct dst_entry *dst)
 336 {
 337         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 338
 339         if (likely(xdst->u.rt6.rt6i_idev))
 340                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 341         xfrm_dst_destroy(xdst);
 342 }
 343
 344 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 345                              int unregister)
 346 {
 347         struct xfrm_dst *xdst;
 348
 349         if (!unregister)
 350                 return;
 351
 352         xdst = (struct xfrm_dst *)dst;
 353         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 354                 struct inet6_dev *loopback_idev = in6_dev_get(&loopback_dev);
 355                 BUG_ON(!loopback_idev);
 356
 357                 do {
 358                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 359                         xdst->u.rt6.rt6i_idev = loopback_idev;
 360                         in6_dev_hold(loopback_idev);
 361                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 362                 } while (xdst->u.dst.xfrm);
 363
 364                 __in6_dev_put(loopback_idev);
 365         }
 366
 367         xfrm_dst_ifdown(dst, dev);
 368 }
 369
 370 static struct dst_ops xfrm6_dst_ops = {
 371         .family =               AF_INET6,
 372         .protocol =             __constant_htons(ETH_P_IPV6),
 373         .gc =                   xfrm6_garbage_collect,
 374         .update_pmtu =          xfrm6_update_pmtu,
 375         .destroy =              xfrm6_dst_destroy,
 376         .ifdown =               xfrm6_dst_ifdown,
 377         .gc_thresh =            1024,
 378         .entry_size =           sizeof(struct xfrm_dst),
 379 };
 380
 381 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 382         .family =               AF_INET6,
 383         .dst_ops =              &xfrm6_dst_ops,
 384         .dst_lookup =           xfrm6_dst_lookup,
 385         .get_saddr =            xfrm6_get_saddr,
 386         .find_bundle =          __xfrm6_find_bundle,
 387         .bundle_create =        __xfrm6_bundle_create,
 388         .decode_session =       _decode_session6,
 389 };
 390
 391 static void __init xfrm6_policy_init(void)
 392 {
 393         xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 394 }
 395
 396 static void xfrm6_policy_fini(void)
 397 {
 398         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 399 }
 400
 401 void __init xfrm6_init(void)
 402 {
 403         xfrm6_policy_init();
 404         xfrm6_state_init();
 405 }
 406
 407 void xfrm6_fini(void)
 408 {
 409         //xfrm6_input_fini();
 410         xfrm6_policy_fini();
 411         xfrm6_state_fini();
 412 }