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