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 <asm/bug.h>
  15 #include <linux/compiler.h>
  16 #include <linux/config.h>
  17 #include <linux/netdevice.h>
  18 #include <net/addrconf.h>
  19 #include <net/xfrm.h>
  20 #include <net/ip.h>
  21 #include <net/ipv6.h>
  22 #include <net/ip6_route.h>
  23
  24 static struct dst_ops xfrm6_dst_ops;
  25 static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
  26
  27 static struct xfrm_type_map xfrm6_type_map = { .lock = RW_LOCK_UNLOCKED };
  28
  29 static int xfrm6_dst_lookup(struct xfrm_dst **dst, struct flowi *fl)
  30 {
  31         int err = 0;
  32         *dst = (struct xfrm_dst*)ip6_route_output(NULL, fl);
  33         if (!*dst)
  34                 err = -ENETUNREACH;
  35         return err;
  36 }
  37
  38 static struct dst_entry *
  39 __xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
  40 {
  41         struct dst_entry *dst;
  42
  43         /* Still not clear if we should set fl->fl6_{src,dst}... */
  44         read_lock_bh(&policy->lock);
  45         for (dst = policy->bundles; dst; dst = dst->next) {
  46                 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
  47                 struct in6_addr fl_dst_prefix, fl_src_prefix;
  48
  49                 ipv6_addr_prefix(&fl_dst_prefix,
  50                                  &fl->fl6_dst,
  51                                  xdst->u.rt6.rt6i_dst.plen);
  52                 ipv6_addr_prefix(&fl_src_prefix,
  53                                  &fl->fl6_src,
  54                                  xdst->u.rt6.rt6i_src.plen);
  55                 if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
  56                     ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
  57                     xfrm_bundle_ok(xdst, fl, AF_INET6)) {
  58                         dst_clone(dst);
  59                         break;
  60                 }
  61         }
  62         read_unlock_bh(&policy->lock);
  63         return dst;
  64 }
  65
  66 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
  67  * all the metrics... Shortly, bundle a bundle.
  68  */
  69
  70 static int
  71 __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
  72                       struct flowi *fl, struct dst_entry **dst_p)
  73 {
  74         struct dst_entry *dst, *dst_prev;
  75         struct rt6_info *rt0 = (struct rt6_info*)(*dst_p);
  76         struct rt6_info *rt  = rt0;
  77         struct in6_addr *remote = &fl->fl6_dst;
  78         struct in6_addr *local  = &fl->fl6_src;
  79         struct flowi fl_tunnel = {
  80                 .nl_u = {
  81                         .ip6_u = {
  82                                 .saddr = *local,
  83                                 .daddr = *remote
  84                         }
  85                 }
  86         };
  87         int i;
  88         int err = 0;
  89         int header_len = 0;
  90         int trailer_len = 0;
  91
  92         dst = dst_prev = NULL;
  93         dst_hold(&rt->u.dst);
  94
  95         for (i = 0; i < nx; i++) {
  96                 struct dst_entry *dst1 = dst_alloc(&xfrm6_dst_ops);
  97                 struct xfrm_dst *xdst;
  98                 int tunnel = 0;
  99
 100                 if (unlikely(dst1 == NULL)) {
 101                         err = -ENOBUFS;
 102                         dst_release(&rt->u.dst);
 103                         goto error;
 104                 }
 105
 106                 if (!dst)
 107                         dst = dst1;
 108                 else {
 109                         dst_prev->child = dst1;
 110                         dst1->flags |= DST_NOHASH;
 111                         dst_clone(dst1);
 112                 }
 113
 114                 xdst = (struct xfrm_dst *)dst1;
 115                 xdst->route = &rt->u.dst;
 116                 if (rt->rt6i_node)
 117                         xdst->route_cookie = rt->rt6i_node->fn_sernum;
 118
 119                 dst1->next = dst_prev;
 120                 dst_prev = dst1;
 121                 if (xfrm[i]->props.mode) {
 122                         remote = (struct in6_addr*)&xfrm[i]->id.daddr;
 123                         local  = (struct in6_addr*)&xfrm[i]->props.saddr;
 124                         tunnel = 1;
 125                 }
 126                 header_len += xfrm[i]->props.header_len;
 127                 trailer_len += xfrm[i]->props.trailer_len;
 128
 129                 if (tunnel) {
 130                         ipv6_addr_copy(&fl_tunnel.fl6_dst, remote);
 131                         ipv6_addr_copy(&fl_tunnel.fl6_src, local);
 132                         err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
 133                                               &fl_tunnel, AF_INET6);
 134                         if (err)
 135                                 goto error;
 136                 } else
 137                         dst_hold(&rt->u.dst);
 138         }
 139
 140         dst_prev->child = &rt->u.dst;
 141         dst->path = &rt->u.dst;
 142         if (rt->rt6i_node)
 143                 ((struct xfrm_dst *)dst)->path_cookie = rt->rt6i_node->fn_sernum;
 144
 145         *dst_p = dst;
 146         dst = dst_prev;
 147
 148         dst_prev = *dst_p;
 149         i = 0;
 150         for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
 151                 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
 152
 153                 dst_prev->xfrm = xfrm[i++];
 154                 dst_prev->dev = rt->u.dst.dev;
 155                 if (rt->u.dst.dev)
 156                         dev_hold(rt->u.dst.dev);
 157                 dst_prev->obsolete      = -1;
 158                 dst_prev->flags        |= DST_HOST;
 159                 dst_prev->lastuse       = jiffies;
 160                 dst_prev->header_len    = header_len;
 161                 dst_prev->trailer_len   = trailer_len;
 162                 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
 163
 164                 /* Copy neighbour for reachability confirmation */
 165                 dst_prev->neighbour     = neigh_clone(rt->u.dst.neighbour);
 166                 dst_prev->input         = rt->u.dst.input;
 167                 dst_prev->output        = xfrm6_output;
 168                 /* Sheit... I remember I did this right. Apparently,
 169                  * it was magically lost, so this code needs audit */
 170                 x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
 171                 x->u.rt6.rt6i_metric   = rt0->rt6i_metric;
 172                 x->u.rt6.rt6i_node     = rt0->rt6i_node;
 173                 x->u.rt6.rt6i_gateway  = rt0->rt6i_gateway;
 174                 memcpy(&x->u.rt6.rt6i_gateway, &rt0->rt6i_gateway, sizeof(x->u.rt6.rt6i_gateway));
 175                 x->u.rt6.rt6i_dst      = rt0->rt6i_dst;
 176                 x->u.rt6.rt6i_src      = rt0->rt6i_src;
 177                 x->u.rt6.rt6i_idev     = rt0->rt6i_idev;
 178                 in6_dev_hold(rt0->rt6i_idev);
 179                 header_len -= x->u.dst.xfrm->props.header_len;
 180                 trailer_len -= x->u.dst.xfrm->props.trailer_len;
 181         }
 182
 183         xfrm_init_pmtu(dst);
 184         return 0;
 185
 186 error:
 187         if (dst)
 188                 dst_free(dst);
 189         return err;
 190 }
 191
 192 static inline void
 193 _decode_session6(struct sk_buff *skb, struct flowi *fl)
 194 {
 195         u16 offset = sizeof(struct ipv6hdr);
 196         struct ipv6hdr *hdr = skb->nh.ipv6h;
 197         struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 198         u8 nexthdr = skb->nh.ipv6h->nexthdr;
 199
 200         memset(fl, 0, sizeof(struct flowi));
 201         ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
 202         ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
 203
 204         while (pskb_may_pull(skb, skb->nh.raw + offset + 1 - skb->data)) {
 205                 switch (nexthdr) {
 206                 case NEXTHDR_ROUTING:
 207                 case NEXTHDR_HOP:
 208                 case NEXTHDR_DEST:
 209                         offset += ipv6_optlen(exthdr);
 210                         nexthdr = exthdr->nexthdr;
 211                         exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 212                         break;
 213
 214                 case IPPROTO_UDP:
 215                 case IPPROTO_TCP:
 216                 case IPPROTO_SCTP:
 217                         if (pskb_may_pull(skb, skb->nh.raw + offset + 4 - skb->data)) {
 218                                 u16 *ports = (u16 *)exthdr;
 219
 220                                 fl->fl_ip_sport = ports[0];
 221                                 fl->fl_ip_dport = ports[1];
 222                         }
 223                         fl->proto = nexthdr;
 224                         return;
 225
 226                 case IPPROTO_ICMPV6:
 227                         if (pskb_may_pull(skb, skb->nh.raw + offset + 2 - skb->data)) {
 228                                 u8 *icmp = (u8 *)exthdr;
 229
 230                                 fl->fl_icmp_type = icmp[0];
 231                                 fl->fl_icmp_code = icmp[1];
 232                         }
 233                         fl->proto = nexthdr;
 234                         return;
 235
 236                 /* XXX Why are there these headers? */
 237                 case IPPROTO_AH:
 238                 case IPPROTO_ESP:
 239                 case IPPROTO_COMP:
 240                 default:
 241                         fl->fl_ipsec_spi = 0;
 242                         fl->proto = nexthdr;
 243                         return;
 244                 };
 245         }
 246 }
 247
 248 static inline int xfrm6_garbage_collect(void)
 249 {
 250         read_lock(&xfrm6_policy_afinfo.lock);
 251         xfrm6_policy_afinfo.garbage_collect();
 252         read_unlock(&xfrm6_policy_afinfo.lock);
 253         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
 254 }
 255
 256 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 257 {
 258         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 259         struct dst_entry *path = xdst->route;
 260
 261         path->ops->update_pmtu(path, mtu);
 262 }
 263
 264 static void xfrm6_dst_destroy(struct dst_entry *dst)
 265 {
 266         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 267
 268         if (likely(xdst->u.rt6.rt6i_idev))
 269                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 270         xfrm_dst_destroy(xdst);
 271 }
 272
 273 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 274                              int unregister)
 275 {
 276         struct xfrm_dst *xdst;
 277
 278         if (!unregister)
 279                 return;
 280
 281         xdst = (struct xfrm_dst *)dst;
 282         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 283                 struct inet6_dev *loopback_idev = in6_dev_get(&loopback_dev);
 284                 BUG_ON(!loopback_idev);
 285
 286                 do {
 287                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 288                         xdst->u.rt6.rt6i_idev = loopback_idev;
 289                         in6_dev_hold(loopback_idev);
 290                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 291                 } while (xdst->u.dst.xfrm);
 292
 293                 __in6_dev_put(loopback_idev);
 294         }
 295
 296         xfrm_dst_ifdown(dst, dev);
 297 }
 298
 299 static struct dst_ops xfrm6_dst_ops = {
 300         .family =               AF_INET6,
 301         .protocol =             __constant_htons(ETH_P_IPV6),
 302         .gc =                   xfrm6_garbage_collect,
 303         .update_pmtu =          xfrm6_update_pmtu,
 304         .destroy =              xfrm6_dst_destroy,
 305         .ifdown =               xfrm6_dst_ifdown,
 306         .gc_thresh =            1024,
 307         .entry_size =           sizeof(struct xfrm_dst),
 308 };
 309
 310 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 311         .family =               AF_INET6,
 312         .lock =                 RW_LOCK_UNLOCKED,
 313         .type_map =             &xfrm6_type_map,
 314         .dst_ops =              &xfrm6_dst_ops,
 315         .dst_lookup =           xfrm6_dst_lookup,
 316         .find_bundle =          __xfrm6_find_bundle,
 317         .bundle_create =        __xfrm6_bundle_create,
 318         .decode_session =       _decode_session6,
 319 };
 320
 321 static void __init xfrm6_policy_init(void)
 322 {
 323         xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 324 }
 325
 326 static void xfrm6_policy_fini(void)
 327 {
 328         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 329 }
 330
 331 void __init xfrm6_init(void)
 332 {
 333         xfrm6_policy_init();
 334         xfrm6_state_init();
 335 }
 336
 337 void xfrm6_fini(void)
 338 {
 339         //xfrm6_input_fini();
 340         xfrm6_policy_fini();
 341         xfrm6_state_fini();
 342 }