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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 **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 struct dst_entry *
  38 __xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
  39 {
  40         struct dst_entry *dst;
  41
  42         /* Still not clear if we should set fl->fl6_{src,dst}... */
  43         read_lock_bh(&policy->lock);
  44         for (dst = policy->bundles; dst; dst = dst->next) {
  45                 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
  46                 struct in6_addr fl_dst_prefix, fl_src_prefix;
  47
  48                 ipv6_addr_prefix(&fl_dst_prefix,
  49                                  &fl->fl6_dst,
  50                                  xdst->u.rt6.rt6i_dst.plen);
  51                 ipv6_addr_prefix(&fl_src_prefix,
  52                                  &fl->fl6_src,
  53                                  xdst->u.rt6.rt6i_src.plen);
  54                 if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
  55                     ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
  56                     xfrm_bundle_ok(xdst, fl, AF_INET6,
  57                                    (xdst->u.rt6.rt6i_dst.plen != 128 ||
  58                                     xdst->u.rt6.rt6i_src.plen != 128))) {
  59                         dst_clone(dst);
  60                         break;
  61                 }
  62         }
  63         read_unlock_bh(&policy->lock);
  64         return dst;
  65 }
  66
  67 static inline struct in6_addr*
  68 __xfrm6_bundle_addr_remote(struct xfrm_state *x, struct in6_addr *addr)
  69 {
  70         return (x->type->remote_addr) ?
  71                 (struct in6_addr*)x->type->remote_addr(x, (xfrm_address_t *)addr) :
  72                 (struct in6_addr*)&x->id.daddr;
  73 }
  74
  75 static inline struct in6_addr*
  76 __xfrm6_bundle_addr_local(struct xfrm_state *x, struct in6_addr *addr)
  77 {
  78         return (x->type->local_addr) ?
  79                 (struct in6_addr*)x->type->local_addr(x, (xfrm_address_t *)addr) :
  80                 (struct in6_addr*)&x->props.saddr;
  81 }
  82
  83 static inline void
  84 __xfrm6_bundle_len_inc(int *len, int *nflen, struct xfrm_state *x)
  85 {
  86         if (x->type->flags & XFRM_TYPE_NON_FRAGMENT)
  87                 *nflen += x->props.header_len;
  88         else
  89                 *len += x->props.header_len;
  90 }
  91
  92 static inline void
  93 __xfrm6_bundle_len_dec(int *len, int *nflen, struct xfrm_state *x)
  94 {
  95         if (x->type->flags & XFRM_TYPE_NON_FRAGMENT)
  96                 *nflen -= x->props.header_len;
  97         else
  98                 *len -= x->props.header_len;
  99 }
 100
 101 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
 102  * all the metrics... Shortly, bundle a bundle.
 103  */
 104
 105 static int
 106 __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
 107                       struct flowi *fl, struct dst_entry **dst_p)
 108 {
 109         struct dst_entry *dst, *dst_prev;
 110         struct rt6_info *rt0 = (struct rt6_info*)(*dst_p);
 111         struct rt6_info *rt  = rt0;
 112         struct in6_addr *remote = &fl->fl6_dst;
 113         struct in6_addr *local  = &fl->fl6_src;
 114         struct flowi fl_tunnel = {
 115                 .nl_u = {
 116                         .ip6_u = {
 117                                 .saddr = *local,
 118                                 .daddr = *remote
 119                         }
 120                 }
 121         };
 122         int i;
 123         int err = 0;
 124         int header_len = 0;
 125         int nfheader_len = 0;
 126         int trailer_len = 0;
 127
 128         dst = dst_prev = NULL;
 129         dst_hold(&rt->u.dst);
 130
 131         for (i = 0; i < nx; i++) {
 132                 struct dst_entry *dst1 = dst_alloc(&xfrm6_dst_ops);
 133                 struct xfrm_dst *xdst;
 134                 int tunnel = 0;
 135
 136                 if (unlikely(dst1 == NULL)) {
 137                         err = -ENOBUFS;
 138                         dst_release(&rt->u.dst);
 139                         goto error;
 140                 }
 141
 142                 if (!dst)
 143                         dst = dst1;
 144                 else {
 145                         dst_prev->child = dst1;
 146                         dst1->flags |= DST_NOHASH;
 147                         dst_clone(dst1);
 148                 }
 149
 150                 xdst = (struct xfrm_dst *)dst1;
 151                 xdst->route = &rt->u.dst;
 152                 xdst->genid = xfrm[i]->genid;
 153                 if (rt->rt6i_node)
 154                         xdst->route_cookie = rt->rt6i_node->fn_sernum;
 155
 156                 dst1->next = dst_prev;
 157                 dst_prev = dst1;
 158                 if (xfrm[i]->props.mode != XFRM_MODE_TRANSPORT) {
 159                         remote = __xfrm6_bundle_addr_remote(xfrm[i], remote);
 160                         local  = __xfrm6_bundle_addr_local(xfrm[i], local);
 161                         tunnel = 1;
 162                 }
 163                 __xfrm6_bundle_len_inc(&header_len, &nfheader_len, xfrm[i]);
 164                 trailer_len += xfrm[i]->props.trailer_len;
 165
 166                 if (tunnel) {
 167                         ipv6_addr_copy(&fl_tunnel.fl6_dst, remote);
 168                         ipv6_addr_copy(&fl_tunnel.fl6_src, local);
 169                         err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
 170                                               &fl_tunnel, AF_INET6);
 171                         if (err)
 172                                 goto error;
 173                 } else
 174                         dst_hold(&rt->u.dst);
 175         }
 176
 177         dst_prev->child = &rt->u.dst;
 178         dst->path = &rt->u.dst;
 179         if (rt->rt6i_node)
 180                 ((struct xfrm_dst *)dst)->path_cookie = rt->rt6i_node->fn_sernum;
 181
 182         *dst_p = dst;
 183         dst = dst_prev;
 184
 185         dst_prev = *dst_p;
 186         i = 0;
 187         for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
 188                 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
 189
 190                 dst_prev->xfrm = xfrm[i++];
 191                 dst_prev->dev = rt->u.dst.dev;
 192                 if (rt->u.dst.dev)
 193                         dev_hold(rt->u.dst.dev);
 194                 dst_prev->obsolete      = -1;
 195                 dst_prev->flags        |= DST_HOST;
 196                 dst_prev->lastuse       = jiffies;
 197                 dst_prev->header_len    = header_len;
 198                 dst_prev->nfheader_len  = nfheader_len;
 199                 dst_prev->trailer_len   = trailer_len;
 200                 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
 201
 202                 /* Copy neighbour for reachability confirmation */
 203                 dst_prev->neighbour     = neigh_clone(rt->u.dst.neighbour);
 204                 dst_prev->input         = rt->u.dst.input;
 205                 dst_prev->output        = xfrm6_output;
 206                 /* Sheit... I remember I did this right. Apparently,
 207                  * it was magically lost, so this code needs audit */
 208                 x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
 209                 x->u.rt6.rt6i_metric   = rt0->rt6i_metric;
 210                 x->u.rt6.rt6i_node     = rt0->rt6i_node;
 211                 x->u.rt6.rt6i_gateway  = rt0->rt6i_gateway;
 212                 memcpy(&x->u.rt6.rt6i_gateway, &rt0->rt6i_gateway, sizeof(x->u.rt6.rt6i_gateway));
 213                 x->u.rt6.rt6i_dst      = rt0->rt6i_dst;
 214                 x->u.rt6.rt6i_src      = rt0->rt6i_src;
 215                 x->u.rt6.rt6i_idev     = rt0->rt6i_idev;
 216                 in6_dev_hold(rt0->rt6i_idev);
 217                 __xfrm6_bundle_len_dec(&header_len, &nfheader_len, x->u.dst.xfrm);
 218                 trailer_len -= x->u.dst.xfrm->props.trailer_len;
 219         }
 220
 221         xfrm_init_pmtu(dst);
 222         return 0;
 223
 224 error:
 225         if (dst)
 226                 dst_free(dst);
 227         return err;
 228 }
 229
 230 static inline void
 231 _decode_session6(struct sk_buff *skb, struct flowi *fl)
 232 {
 233         u16 offset = skb->h.raw - skb->nh.raw;
 234         struct ipv6hdr *hdr = skb->nh.ipv6h;
 235         struct ipv6_opt_hdr *exthdr;
 236         u8 nexthdr = skb->nh.raw[IP6CB(skb)->nhoff];
 237
 238         memset(fl, 0, sizeof(struct flowi));
 239         ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
 240         ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
 241
 242         while (pskb_may_pull(skb, skb->nh.raw + offset + 1 - skb->data)) {
 243                 exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 244
 245                 switch (nexthdr) {
 246                 case NEXTHDR_ROUTING:
 247                 case NEXTHDR_HOP:
 248                 case NEXTHDR_DEST:
 249                         offset += ipv6_optlen(exthdr);
 250                         nexthdr = exthdr->nexthdr;
 251                         exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 252                         break;
 253
 254                 case IPPROTO_UDP:
 255                 case IPPROTO_TCP:
 256                 case IPPROTO_SCTP:
 257                 case IPPROTO_DCCP:
 258                         if (pskb_may_pull(skb, skb->nh.raw + offset + 4 - skb->data)) {
 259                                 u16 *ports = (u16 *)exthdr;
 260
 261                                 fl->fl_ip_sport = ports[0];
 262                                 fl->fl_ip_dport = ports[1];
 263                         }
 264                         fl->proto = nexthdr;
 265                         return;
 266
 267                 case IPPROTO_ICMPV6:
 268                         if (pskb_may_pull(skb, skb->nh.raw + offset + 2 - skb->data)) {
 269                                 u8 *icmp = (u8 *)exthdr;
 270
 271                                 fl->fl_icmp_type = icmp[0];
 272                                 fl->fl_icmp_code = icmp[1];
 273                         }
 274                         fl->proto = nexthdr;
 275                         return;
 276
 277 #ifdef CONFIG_IPV6_MIP6
 278                 case IPPROTO_MH:
 279                         if (pskb_may_pull(skb, skb->nh.raw + offset + 3 - skb->data)) {
 280                                 struct ip6_mh *mh;
 281                                 mh = (struct ip6_mh *)exthdr;
 282
 283                                 fl->fl_mh_type = mh->ip6mh_type;
 284                         }
 285                         fl->proto = nexthdr;
 286                         return;
 287 #endif
 288
 289                 /* XXX Why are there these headers? */
 290                 case IPPROTO_AH:
 291                 case IPPROTO_ESP:
 292                 case IPPROTO_COMP:
 293                 default:
 294                         fl->fl_ipsec_spi = 0;
 295                         fl->proto = nexthdr;
 296                         return;
 297                 };
 298         }
 299 }
 300
 301 static inline int xfrm6_garbage_collect(void)
 302 {
 303         xfrm6_policy_afinfo.garbage_collect();
 304         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
 305 }
 306
 307 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 308 {
 309         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 310         struct dst_entry *path = xdst->route;
 311
 312         path->ops->update_pmtu(path, mtu);
 313 }
 314
 315 static void xfrm6_dst_destroy(struct dst_entry *dst)
 316 {
 317         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 318
 319         if (likely(xdst->u.rt6.rt6i_idev))
 320                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 321         xfrm_dst_destroy(xdst);
 322 }
 323
 324 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 325                              int unregister)
 326 {
 327         struct xfrm_dst *xdst;
 328
 329         if (!unregister)
 330                 return;
 331
 332         xdst = (struct xfrm_dst *)dst;
 333         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 334                 struct inet6_dev *loopback_idev = in6_dev_get(&loopback_dev);
 335                 BUG_ON(!loopback_idev);
 336
 337                 do {
 338                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 339                         xdst->u.rt6.rt6i_idev = loopback_idev;
 340                         in6_dev_hold(loopback_idev);
 341                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 342                 } while (xdst->u.dst.xfrm);
 343
 344                 __in6_dev_put(loopback_idev);
 345         }
 346
 347         xfrm_dst_ifdown(dst, dev);
 348 }
 349
 350 static struct dst_ops xfrm6_dst_ops = {
 351         .family =               AF_INET6,
 352         .protocol =             __constant_htons(ETH_P_IPV6),
 353         .gc =                   xfrm6_garbage_collect,
 354         .update_pmtu =          xfrm6_update_pmtu,
 355         .destroy =              xfrm6_dst_destroy,
 356         .ifdown =               xfrm6_dst_ifdown,
 357         .gc_thresh =            1024,
 358         .entry_size =           sizeof(struct xfrm_dst),
 359 };
 360
 361 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 362         .family =               AF_INET6,
 363         .dst_ops =              &xfrm6_dst_ops,
 364         .dst_lookup =           xfrm6_dst_lookup,
 365         .find_bundle =          __xfrm6_find_bundle,
 366         .bundle_create =        __xfrm6_bundle_create,
 367         .decode_session =       _decode_session6,
 368 };
 369
 370 static void __init xfrm6_policy_init(void)
 371 {
 372         xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 373 }
 374
 375 static void xfrm6_policy_fini(void)
 376 {
 377         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 378 }
 379
 380 void __init xfrm6_init(void)
 381 {
 382         xfrm6_policy_init();
 383         xfrm6_state_init();
 384 }
 385
 386 void xfrm6_fini(void)
 387 {
 388         //xfrm6_input_fini();
 389         xfrm6_policy_fini();
 390         xfrm6_state_fini();
 391 }