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