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/err.h>
  15 #include <linux/kernel.h>
  16 #include <linux/netdevice.h>
  17 #include <net/addrconf.h>
  18 #include <net/dst.h>
  19 #include <net/xfrm.h>
  20 #include <net/ip.h>
  21 #include <net/ipv6.h>
  22 #include <net/ip6_route.h>
  23 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
  24 #include <net/mip6.h>
  25 #endif
  26
  27 static struct dst_ops xfrm6_dst_ops;
  28 static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
  29
  30 static struct dst_entry *xfrm6_dst_lookup(int tos, xfrm_address_t *saddr,
  31                                           xfrm_address_t *daddr)
  32 {
  33         struct flowi fl = {};
  34         struct dst_entry *dst;
  35         int err;
  36
  37         memcpy(&fl.fl6_dst, daddr, sizeof(fl.fl6_dst));
  38         if (saddr)
  39                 memcpy(&fl.fl6_src, saddr, sizeof(fl.fl6_src));
  40
  41         dst = ip6_route_output(NULL, &fl);
  42
  43         err = dst->error;
  44         if (dst->error) {
  45                 dst_release(dst);
  46                 dst = ERR_PTR(err);
  47         }
  48
  49         return dst;
  50 }
  51
  52 static int xfrm6_get_saddr(xfrm_address_t *saddr, xfrm_address_t *daddr)
  53 {
  54         struct dst_entry *dst;
  55
  56         dst = xfrm6_dst_lookup(0, NULL, daddr);
  57         if (IS_ERR(dst))
  58                 return -EHOSTUNREACH;
  59
  60         ipv6_get_saddr(dst, (struct in6_addr *)&daddr->a6,
  61                        (struct in6_addr *)&saddr->a6);
  62         dst_release(dst);
  63         return 0;
  64 }
  65
  66 static struct dst_entry *
  67 __xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
  68 {
  69         struct dst_entry *dst;
  70
  71         /* Still not clear if we should set fl->fl6_{src,dst}... */
  72         read_lock_bh(&policy->lock);
  73         for (dst = policy->bundles; dst; dst = dst->next) {
  74                 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
  75                 struct in6_addr fl_dst_prefix, fl_src_prefix;
  76
  77                 ipv6_addr_prefix(&fl_dst_prefix,
  78                                  &fl->fl6_dst,
  79                                  xdst->u.rt6.rt6i_dst.plen);
  80                 ipv6_addr_prefix(&fl_src_prefix,
  81                                  &fl->fl6_src,
  82                                  xdst->u.rt6.rt6i_src.plen);
  83                 if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
  84                     ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
  85                     xfrm_bundle_ok(policy, xdst, fl, AF_INET6,
  86                                    (xdst->u.rt6.rt6i_dst.plen != 128 ||
  87                                     xdst->u.rt6.rt6i_src.plen != 128))) {
  88                         dst_clone(dst);
  89                         break;
  90                 }
  91         }
  92         read_unlock_bh(&policy->lock);
  93         return dst;
  94 }
  95
  96 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
  97  * all the metrics... Shortly, bundle a bundle.
  98  */
  99
 100 static int
 101 __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
 102                       struct flowi *fl, struct dst_entry **dst_p)
 103 {
 104         struct dst_entry *dst, *dst_prev;
 105         struct rt6_info *rt0 = (struct rt6_info*)(*dst_p);
 106         struct rt6_info *rt  = rt0;
 107         int i;
 108         int err;
 109         int header_len = 0;
 110         int trailer_len = 0;
 111
 112         dst = dst_prev = NULL;
 113         dst_hold(&rt->u.dst);
 114
 115         for (i = 0; i < nx; i++) {
 116                 struct dst_entry *dst1 = dst_alloc(&xfrm6_dst_ops);
 117                 struct xfrm_dst *xdst;
 118
 119                 if (unlikely(dst1 == NULL)) {
 120                         err = -ENOBUFS;
 121                         dst_release(&rt->u.dst);
 122                         goto error;
 123                 }
 124
 125                 if (!dst)
 126                         dst = dst1;
 127                 else {
 128                         dst_prev->child = dst1;
 129                         dst1->flags |= DST_NOHASH;
 130                         dst_clone(dst1);
 131                 }
 132
 133                 xdst = (struct xfrm_dst *)dst1;
 134                 xdst->route = &rt->u.dst;
 135                 xdst->genid = xfrm[i]->genid;
 136                 if (rt->rt6i_node)
 137                         xdst->route_cookie = rt->rt6i_node->fn_sernum;
 138
 139                 dst1->next = dst_prev;
 140                 dst_prev = dst1;
 141
 142                 if (xfrm[i]->type->flags & XFRM_TYPE_NON_FRAGMENT)
 143                         ((struct rt6_info *)dst)->nfheader_len +=
 144                                 xfrm[i]->props.header_len;
 145                 header_len += xfrm[i]->props.header_len;
 146                 trailer_len += xfrm[i]->props.trailer_len;
 147
 148                 if (xfrm[i]->props.mode != XFRM_MODE_TRANSPORT) {
 149                         dst1 = xfrm_dst_lookup(xfrm[i], 0);
 150                         err = PTR_ERR(dst1);
 151                         if (IS_ERR(dst1))
 152                                 goto error;
 153
 154                         rt = (struct rt6_info *)dst1;
 155                 } else
 156                         dst_hold(&rt->u.dst);
 157         }
 158
 159         dst_prev->child = &rt->u.dst;
 160         dst->path = &rt->u.dst;
 161
 162         /* Copy neighbour for reachability confirmation */
 163         dst->neighbour = neigh_clone(rt->u.dst.neighbour);
 164
 165         if (rt->rt6i_node)
 166                 ((struct xfrm_dst *)dst)->path_cookie = rt->rt6i_node->fn_sernum;
 167
 168         *dst_p = dst;
 169         dst = dst_prev;
 170
 171         dst_prev = *dst_p;
 172         i = 0;
 173         err = -ENODEV;
 174         for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
 175                 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
 176
 177                 dst_prev->xfrm = xfrm[i++];
 178                 dst_prev->dev = rt->u.dst.dev;
 179                 if (!rt->u.dst.dev)
 180                         goto error;
 181                 dev_hold(rt->u.dst.dev);
 182
 183                 x->u.rt6.rt6i_idev = in6_dev_get(rt->u.dst.dev);
 184                 if (!x->u.rt6.rt6i_idev)
 185                         goto error;
 186
 187                 dst_prev->obsolete      = -1;
 188                 dst_prev->flags        |= DST_HOST;
 189                 dst_prev->lastuse       = jiffies;
 190                 dst_prev->header_len    = header_len;
 191                 dst_prev->trailer_len   = trailer_len;
 192                 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
 193
 194                 dst_prev->input = dst_discard;
 195                 dst_prev->output = dst_prev->xfrm->outer_mode->afinfo->output;
 196                 /* Sheit... I remember I did this right. Apparently,
 197                  * it was magically lost, so this code needs audit */
 198                 x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTF_ANYCAST|RTF_LOCAL);
 199                 x->u.rt6.rt6i_metric   = rt0->rt6i_metric;
 200                 x->u.rt6.rt6i_node     = rt0->rt6i_node;
 201                 x->u.rt6.rt6i_gateway  = rt0->rt6i_gateway;
 202                 memcpy(&x->u.rt6.rt6i_gateway, &rt0->rt6i_gateway, sizeof(x->u.rt6.rt6i_gateway));
 203                 x->u.rt6.rt6i_dst      = rt0->rt6i_dst;
 204                 x->u.rt6.rt6i_src      = rt0->rt6i_src;
 205                 header_len -= x->u.dst.xfrm->props.header_len;
 206                 trailer_len -= x->u.dst.xfrm->props.trailer_len;
 207         }
 208
 209         xfrm_init_pmtu(dst);
 210         return 0;
 211
 212 error:
 213         if (dst)
 214                 dst_free(dst);
 215         return err;
 216 }
 217
 218 static inline void
 219 _decode_session6(struct sk_buff *skb, struct flowi *fl)
 220 {
 221         u16 offset = skb_network_header_len(skb);
 222         struct ipv6hdr *hdr = ipv6_hdr(skb);
 223         struct ipv6_opt_hdr *exthdr;
 224         const unsigned char *nh = skb_network_header(skb);
 225         u8 nexthdr = nh[IP6CB(skb)->nhoff];
 226
 227         memset(fl, 0, sizeof(struct flowi));
 228         ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
 229         ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
 230
 231         while (pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
 232                 nh = skb_network_header(skb);
 233                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 234
 235                 switch (nexthdr) {
 236                 case NEXTHDR_ROUTING:
 237                 case NEXTHDR_HOP:
 238                 case NEXTHDR_DEST:
 239                         offset += ipv6_optlen(exthdr);
 240                         nexthdr = exthdr->nexthdr;
 241                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 242                         break;
 243
 244                 case IPPROTO_UDP:
 245                 case IPPROTO_UDPLITE:
 246                 case IPPROTO_TCP:
 247                 case IPPROTO_SCTP:
 248                 case IPPROTO_DCCP:
 249                         if (pskb_may_pull(skb, nh + offset + 4 - skb->data)) {
 250                                 __be16 *ports = (__be16 *)exthdr;
 251
 252                                 fl->fl_ip_sport = ports[0];
 253                                 fl->fl_ip_dport = ports[1];
 254                         }
 255                         fl->proto = nexthdr;
 256                         return;
 257
 258                 case IPPROTO_ICMPV6:
 259                         if (pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
 260                                 u8 *icmp = (u8 *)exthdr;
 261
 262                                 fl->fl_icmp_type = icmp[0];
 263                                 fl->fl_icmp_code = icmp[1];
 264                         }
 265                         fl->proto = nexthdr;
 266                         return;
 267
 268 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 269                 case IPPROTO_MH:
 270                         if (pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
 271                                 struct ip6_mh *mh;
 272                                 mh = (struct ip6_mh *)exthdr;
 273
 274                                 fl->fl_mh_type = mh->ip6mh_type;
 275                         }
 276                         fl->proto = nexthdr;
 277                         return;
 278 #endif
 279
 280                 /* XXX Why are there these headers? */
 281                 case IPPROTO_AH:
 282                 case IPPROTO_ESP:
 283                 case IPPROTO_COMP:
 284                 default:
 285                         fl->fl_ipsec_spi = 0;
 286                         fl->proto = nexthdr;
 287                         return;
 288                 }
 289         }
 290 }
 291
 292 static inline int xfrm6_garbage_collect(void)
 293 {
 294         xfrm6_policy_afinfo.garbage_collect();
 295         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
 296 }
 297
 298 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 299 {
 300         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 301         struct dst_entry *path = xdst->route;
 302
 303         path->ops->update_pmtu(path, mtu);
 304 }
 305
 306 static void xfrm6_dst_destroy(struct dst_entry *dst)
 307 {
 308         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 309
 310         if (likely(xdst->u.rt6.rt6i_idev))
 311                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 312         xfrm_dst_destroy(xdst);
 313 }
 314
 315 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 316                              int unregister)
 317 {
 318         struct xfrm_dst *xdst;
 319
 320         if (!unregister)
 321                 return;
 322
 323         xdst = (struct xfrm_dst *)dst;
 324         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 325                 struct inet6_dev *loopback_idev = in6_dev_get(init_net.loopback_dev);
 326                 BUG_ON(!loopback_idev);
 327
 328                 do {
 329                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 330                         xdst->u.rt6.rt6i_idev = loopback_idev;
 331                         in6_dev_hold(loopback_idev);
 332                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 333                 } while (xdst->u.dst.xfrm);
 334
 335                 __in6_dev_put(loopback_idev);
 336         }
 337
 338         xfrm_dst_ifdown(dst, dev);
 339 }
 340
 341 static struct dst_ops xfrm6_dst_ops = {
 342         .family =               AF_INET6,
 343         .protocol =             __constant_htons(ETH_P_IPV6),
 344         .gc =                   xfrm6_garbage_collect,
 345         .update_pmtu =          xfrm6_update_pmtu,
 346         .destroy =              xfrm6_dst_destroy,
 347         .ifdown =               xfrm6_dst_ifdown,
 348         .gc_thresh =            1024,
 349         .entry_size =           sizeof(struct xfrm_dst),
 350 };
 351
 352 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 353         .family =               AF_INET6,
 354         .dst_ops =              &xfrm6_dst_ops,
 355         .dst_lookup =           xfrm6_dst_lookup,
 356         .get_saddr =            xfrm6_get_saddr,
 357         .find_bundle =          __xfrm6_find_bundle,
 358         .bundle_create =        __xfrm6_bundle_create,
 359         .decode_session =       _decode_session6,
 360 };
 361
 362 static void __init xfrm6_policy_init(void)
 363 {
 364         xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 365 }
 366
 367 static void xfrm6_policy_fini(void)
 368 {
 369         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 370 }
 371
 372 void __init xfrm6_init(void)
 373 {
 374         xfrm6_policy_init();
 375         xfrm6_state_init();
 376 }
 377
 378 void xfrm6_fini(void)
 379 {
 380         //xfrm6_input_fini();
 381         xfrm6_policy_fini();
 382         xfrm6_state_fini();
 383 }