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
  22 static struct dst_ops xfrm6_dst_ops;
  23 static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
  24
  25 static int xfrm6_dst_lookup(struct xfrm_dst **dst, struct flowi *fl)
  26 {
  27         int err = 0;
  28         *dst = (struct xfrm_dst*)ip6_route_output(NULL, fl);
  29         if (!*dst)
  30                 err = -ENETUNREACH;
  31         return err;
  32 }
  33
  34 static struct dst_entry *
  35 __xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
  36 {
  37         struct dst_entry *dst;
  38
  39         /* Still not clear if we should set fl->fl6_{src,dst}... */
  40         read_lock_bh(&policy->lock);
  41         for (dst = policy->bundles; dst; dst = dst->next) {
  42                 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
  43                 struct in6_addr fl_dst_prefix, fl_src_prefix;
  44
  45                 ipv6_addr_prefix(&fl_dst_prefix,
  46                                  &fl->fl6_dst,
  47                                  xdst->u.rt6.rt6i_dst.plen);
  48                 ipv6_addr_prefix(&fl_src_prefix,
  49                                  &fl->fl6_src,
  50                                  xdst->u.rt6.rt6i_src.plen);
  51                 if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
  52                     ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
  53                     xfrm_bundle_ok(xdst, fl, AF_INET6,
  54                                    (xdst->u.rt6.rt6i_dst.plen != 128 ||
  55                                     xdst->u.rt6.rt6i_src.plen != 128))) {
  56                         dst_clone(dst);
  57                         break;
  58                 }
  59         }
  60         read_unlock_bh(&policy->lock);
  61         return dst;
  62 }
  63
  64 static inline struct in6_addr*
  65 __xfrm6_bundle_addr_remote(struct xfrm_state *x, struct in6_addr *addr)
  66 {
  67         return (x->type->remote_addr) ?
  68                 (struct in6_addr*)x->type->remote_addr(x, (xfrm_address_t *)addr) :
  69                 (struct in6_addr*)&x->id.daddr;
  70 }
  71
  72 static inline struct in6_addr*
  73 __xfrm6_bundle_addr_local(struct xfrm_state *x, struct in6_addr *addr)
  74 {
  75         return (x->type->local_addr) ?
  76                 (struct in6_addr*)x->type->local_addr(x, (xfrm_address_t *)addr) :
  77                 (struct in6_addr*)&x->props.saddr;
  78 }
  79
  80 static inline void
  81 __xfrm6_bundle_len_inc(int *len, int *nflen, struct xfrm_state *x)
  82 {
  83         if (x->type->flags & XFRM_TYPE_NON_FRAGMENT)
  84                 *nflen += x->props.header_len;
  85         else
  86                 *len += x->props.header_len;
  87 }
  88
  89 static inline void
  90 __xfrm6_bundle_len_dec(int *len, int *nflen, struct xfrm_state *x)
  91 {
  92         if (x->type->flags & XFRM_TYPE_NON_FRAGMENT)
  93                 *nflen -= x->props.header_len;
  94         else
  95                 *len -= x->props.header_len;
  96 }
  97
  98 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
  99  * all the metrics... Shortly, bundle a bundle.
 100  */
 101
 102 static int
 103 __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
 104                       struct flowi *fl, struct dst_entry **dst_p)
 105 {
 106         struct dst_entry *dst, *dst_prev;
 107         struct rt6_info *rt0 = (struct rt6_info*)(*dst_p);
 108         struct rt6_info *rt  = rt0;
 109         struct in6_addr *remote = &fl->fl6_dst;
 110         struct in6_addr *local  = &fl->fl6_src;
 111         struct flowi fl_tunnel = {
 112                 .nl_u = {
 113                         .ip6_u = {
 114                                 .saddr = *local,
 115                                 .daddr = *remote
 116                         }
 117                 }
 118         };
 119         int i;
 120         int err = 0;
 121         int header_len = 0;
 122         int nfheader_len = 0;
 123         int trailer_len = 0;
 124
 125         dst = dst_prev = NULL;
 126         dst_hold(&rt->u.dst);
 127
 128         for (i = 0; i < nx; i++) {
 129                 struct dst_entry *dst1 = dst_alloc(&xfrm6_dst_ops);
 130                 struct xfrm_dst *xdst;
 131                 int tunnel = 0;
 132
 133                 if (unlikely(dst1 == NULL)) {
 134                         err = -ENOBUFS;
 135                         dst_release(&rt->u.dst);
 136                         goto error;
 137                 }
 138
 139                 if (!dst)
 140                         dst = dst1;
 141                 else {
 142                         dst_prev->child = dst1;
 143                         dst1->flags |= DST_NOHASH;
 144                         dst_clone(dst1);
 145                 }
 146
 147                 xdst = (struct xfrm_dst *)dst1;
 148                 xdst->route = &rt->u.dst;
 149                 if (rt->rt6i_node)
 150                         xdst->route_cookie = rt->rt6i_node->fn_sernum;
 151
 152                 dst1->next = dst_prev;
 153                 dst_prev = dst1;
 154                 if (xfrm[i]->props.mode != XFRM_MODE_TRANSPORT) {
 155                         remote = __xfrm6_bundle_addr_remote(xfrm[i], remote);
 156                         local  = __xfrm6_bundle_addr_local(xfrm[i], local);
 157                         tunnel = 1;
 158                 }
 159                 __xfrm6_bundle_len_inc(&header_len, &nfheader_len, xfrm[i]);
 160                 trailer_len += xfrm[i]->props.trailer_len;
 161
 162                 if (tunnel) {
 163                         ipv6_addr_copy(&fl_tunnel.fl6_dst, remote);
 164                         ipv6_addr_copy(&fl_tunnel.fl6_src, local);
 165                         err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
 166                                               &fl_tunnel, AF_INET6);
 167                         if (err)
 168                                 goto error;
 169                 } else
 170                         dst_hold(&rt->u.dst);
 171         }
 172
 173         dst_prev->child = &rt->u.dst;
 174         dst->path = &rt->u.dst;
 175         if (rt->rt6i_node)
 176                 ((struct xfrm_dst *)dst)->path_cookie = rt->rt6i_node->fn_sernum;
 177
 178         *dst_p = dst;
 179         dst = dst_prev;
 180
 181         dst_prev = *dst_p;
 182         i = 0;
 183         for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
 184                 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
 185
 186                 dst_prev->xfrm = xfrm[i++];
 187                 dst_prev->dev = rt->u.dst.dev;
 188                 if (rt->u.dst.dev)
 189                         dev_hold(rt->u.dst.dev);
 190                 dst_prev->obsolete      = -1;
 191                 dst_prev->flags        |= DST_HOST;
 192                 dst_prev->lastuse       = jiffies;
 193                 dst_prev->header_len    = header_len;
 194                 dst_prev->nfheader_len  = nfheader_len;
 195                 dst_prev->trailer_len   = trailer_len;
 196                 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
 197
 198                 /* Copy neighbour for reachability confirmation */
 199                 dst_prev->neighbour     = neigh_clone(rt->u.dst.neighbour);
 200                 dst_prev->input         = rt->u.dst.input;
 201                 dst_prev->output        = xfrm6_output;
 202                 /* Sheit... I remember I did this right. Apparently,
 203                  * it was magically lost, so this code needs audit */
 204                 x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
 205                 x->u.rt6.rt6i_metric   = rt0->rt6i_metric;
 206                 x->u.rt6.rt6i_node     = rt0->rt6i_node;
 207                 x->u.rt6.rt6i_gateway  = rt0->rt6i_gateway;
 208                 memcpy(&x->u.rt6.rt6i_gateway, &rt0->rt6i_gateway, sizeof(x->u.rt6.rt6i_gateway));
 209                 x->u.rt6.rt6i_dst      = rt0->rt6i_dst;
 210                 x->u.rt6.rt6i_src      = rt0->rt6i_src;
 211                 x->u.rt6.rt6i_idev     = rt0->rt6i_idev;
 212                 in6_dev_hold(rt0->rt6i_idev);
 213                 __xfrm6_bundle_len_dec(&header_len, &nfheader_len, x->u.dst.xfrm);
 214                 trailer_len -= x->u.dst.xfrm->props.trailer_len;
 215         }
 216
 217         xfrm_init_pmtu(dst);
 218         return 0;
 219
 220 error:
 221         if (dst)
 222                 dst_free(dst);
 223         return err;
 224 }
 225
 226 static inline void
 227 _decode_session6(struct sk_buff *skb, struct flowi *fl)
 228 {
 229         u16 offset = skb->h.raw - skb->nh.raw;
 230         struct ipv6hdr *hdr = skb->nh.ipv6h;
 231         struct ipv6_opt_hdr *exthdr;
 232         u8 nexthdr = skb->nh.raw[IP6CB(skb)->nhoff];
 233
 234         memset(fl, 0, sizeof(struct flowi));
 235         ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
 236         ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
 237
 238         while (pskb_may_pull(skb, skb->nh.raw + offset + 1 - skb->data)) {
 239                 exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 240
 241                 switch (nexthdr) {
 242                 case NEXTHDR_ROUTING:
 243                 case NEXTHDR_HOP:
 244                 case NEXTHDR_DEST:
 245                         offset += ipv6_optlen(exthdr);
 246                         nexthdr = exthdr->nexthdr;
 247                         exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 248                         break;
 249
 250                 case IPPROTO_UDP:
 251                 case IPPROTO_TCP:
 252                 case IPPROTO_SCTP:
 253                 case IPPROTO_DCCP:
 254                         if (pskb_may_pull(skb, skb->nh.raw + offset + 4 - skb->data)) {
 255                                 u16 *ports = (u16 *)exthdr;
 256
 257                                 fl->fl_ip_sport = ports[0];
 258                                 fl->fl_ip_dport = ports[1];
 259                         }
 260                         fl->proto = nexthdr;
 261                         return;
 262
 263                 case IPPROTO_ICMPV6:
 264                         if (pskb_may_pull(skb, skb->nh.raw + offset + 2 - skb->data)) {
 265                                 u8 *icmp = (u8 *)exthdr;
 266
 267                                 fl->fl_icmp_type = icmp[0];
 268                                 fl->fl_icmp_code = icmp[1];
 269                         }
 270                         fl->proto = nexthdr;
 271                         return;
 272
 273                 /* XXX Why are there these headers? */
 274                 case IPPROTO_AH:
 275                 case IPPROTO_ESP:
 276                 case IPPROTO_COMP:
 277                 default:
 278                         fl->fl_ipsec_spi = 0;
 279                         fl->proto = nexthdr;
 280                         return;
 281                 };
 282         }
 283 }
 284
 285 static inline int xfrm6_garbage_collect(void)
 286 {
 287         xfrm6_policy_afinfo.garbage_collect();
 288         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
 289 }
 290
 291 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 292 {
 293         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 294         struct dst_entry *path = xdst->route;
 295
 296         path->ops->update_pmtu(path, mtu);
 297 }
 298
 299 static void xfrm6_dst_destroy(struct dst_entry *dst)
 300 {
 301         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 302
 303         if (likely(xdst->u.rt6.rt6i_idev))
 304                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 305         xfrm_dst_destroy(xdst);
 306 }
 307
 308 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 309                              int unregister)
 310 {
 311         struct xfrm_dst *xdst;
 312
 313         if (!unregister)
 314                 return;
 315
 316         xdst = (struct xfrm_dst *)dst;
 317         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 318                 struct inet6_dev *loopback_idev = in6_dev_get(&loopback_dev);
 319                 BUG_ON(!loopback_idev);
 320
 321                 do {
 322                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 323                         xdst->u.rt6.rt6i_idev = loopback_idev;
 324                         in6_dev_hold(loopback_idev);
 325                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 326                 } while (xdst->u.dst.xfrm);
 327
 328                 __in6_dev_put(loopback_idev);
 329         }
 330
 331         xfrm_dst_ifdown(dst, dev);
 332 }
 333
 334 static struct dst_ops xfrm6_dst_ops = {
 335         .family =               AF_INET6,
 336         .protocol =             __constant_htons(ETH_P_IPV6),
 337         .gc =                   xfrm6_garbage_collect,
 338         .update_pmtu =          xfrm6_update_pmtu,
 339         .destroy =              xfrm6_dst_destroy,
 340         .ifdown =               xfrm6_dst_ifdown,
 341         .gc_thresh =            1024,
 342         .entry_size =           sizeof(struct xfrm_dst),
 343 };
 344
 345 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 346         .family =               AF_INET6,
 347         .dst_ops =              &xfrm6_dst_ops,
 348         .dst_lookup =           xfrm6_dst_lookup,
 349         .find_bundle =          __xfrm6_find_bundle,
 350         .bundle_create =        __xfrm6_bundle_create,
 351         .decode_session =       _decode_session6,
 352 };
 353
 354 static void __init xfrm6_policy_init(void)
 355 {
 356         xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 357 }
 358
 359 static void xfrm6_policy_fini(void)
 360 {
 361         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 362 }
 363
 364 void __init xfrm6_init(void)
 365 {
 366         xfrm6_policy_init();
 367         xfrm6_state_init();
 368 }
 369
 370 void xfrm6_fini(void)
 371 {
 372         //xfrm6_input_fini();
 373         xfrm6_policy_fini();
 374         xfrm6_state_fini();
 375 }