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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/config.h>
  16 #include <linux/netdevice.h>
  17 #include <net/addrconf.h>
  18 #include <net/xfrm.h>
  19 #include <net/ip.h>
  20 #include <net/ipv6.h>
  21 #include <net/ip6_route.h>
  22
  23 static struct dst_ops xfrm6_dst_ops;
  24 static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
  25
  26 static int xfrm6_dst_lookup(struct xfrm_dst **dst, struct flowi *fl)
  27 {
  28         int err = 0;
  29         *dst = (struct xfrm_dst*)ip6_route_output(NULL, fl);
  30         if (!*dst)
  31                 err = -ENETUNREACH;
  32         return err;
  33 }
  34
  35 static struct dst_entry *
  36 __xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
  37 {
  38         struct dst_entry *dst;
  39
  40         /* Still not clear if we should set fl->fl6_{src,dst}... */
  41         read_lock_bh(&policy->lock);
  42         for (dst = policy->bundles; dst; dst = dst->next) {
  43                 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
  44                 struct in6_addr fl_dst_prefix, fl_src_prefix;
  45
  46                 ipv6_addr_prefix(&fl_dst_prefix,
  47                                  &fl->fl6_dst,
  48                                  xdst->u.rt6.rt6i_dst.plen);
  49                 ipv6_addr_prefix(&fl_src_prefix,
  50                                  &fl->fl6_src,
  51                                  xdst->u.rt6.rt6i_src.plen);
  52                 if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
  53                     ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
  54                     xfrm_bundle_ok(xdst, fl, AF_INET6)) {
  55                         dst_clone(dst);
  56                         break;
  57                 }
  58         }
  59         read_unlock_bh(&policy->lock);
  60         return dst;
  61 }
  62
  63 /* Allocate chain of dst_entry's, attach known xfrm's, calculate
  64  * all the metrics... Shortly, bundle a bundle.
  65  */
  66
  67 static int
  68 __xfrm6_bundle_create(struct xfrm_policy *policy, struct xfrm_state **xfrm, int nx,
  69                       struct flowi *fl, struct dst_entry **dst_p)
  70 {
  71         struct dst_entry *dst, *dst_prev;
  72         struct rt6_info *rt0 = (struct rt6_info*)(*dst_p);
  73         struct rt6_info *rt  = rt0;
  74         struct in6_addr *remote = &fl->fl6_dst;
  75         struct in6_addr *local  = &fl->fl6_src;
  76         struct flowi fl_tunnel = {
  77                 .nl_u = {
  78                         .ip6_u = {
  79                                 .saddr = *local,
  80                                 .daddr = *remote
  81                         }
  82                 }
  83         };
  84         int i;
  85         int err = 0;
  86         int header_len = 0;
  87         int trailer_len = 0;
  88
  89         dst = dst_prev = NULL;
  90         dst_hold(&rt->u.dst);
  91
  92         for (i = 0; i < nx; i++) {
  93                 struct dst_entry *dst1 = dst_alloc(&xfrm6_dst_ops);
  94                 struct xfrm_dst *xdst;
  95                 int tunnel = 0;
  96
  97                 if (unlikely(dst1 == NULL)) {
  98                         err = -ENOBUFS;
  99                         dst_release(&rt->u.dst);
 100                         goto error;
 101                 }
 102
 103                 if (!dst)
 104                         dst = dst1;
 105                 else {
 106                         dst_prev->child = dst1;
 107                         dst1->flags |= DST_NOHASH;
 108                         dst_clone(dst1);
 109                 }
 110
 111                 xdst = (struct xfrm_dst *)dst1;
 112                 xdst->route = &rt->u.dst;
 113                 if (rt->rt6i_node)
 114                         xdst->route_cookie = rt->rt6i_node->fn_sernum;
 115
 116                 dst1->next = dst_prev;
 117                 dst_prev = dst1;
 118                 if (xfrm[i]->props.mode) {
 119                         remote = (struct in6_addr*)&xfrm[i]->id.daddr;
 120                         local  = (struct in6_addr*)&xfrm[i]->props.saddr;
 121                         tunnel = 1;
 122                 }
 123                 header_len += xfrm[i]->props.header_len;
 124                 trailer_len += xfrm[i]->props.trailer_len;
 125
 126                 if (tunnel) {
 127                         ipv6_addr_copy(&fl_tunnel.fl6_dst, remote);
 128                         ipv6_addr_copy(&fl_tunnel.fl6_src, local);
 129                         err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
 130                                               &fl_tunnel, AF_INET6);
 131                         if (err)
 132                                 goto error;
 133                 } else
 134                         dst_hold(&rt->u.dst);
 135         }
 136
 137         dst_prev->child = &rt->u.dst;
 138         dst->path = &rt->u.dst;
 139         if (rt->rt6i_node)
 140                 ((struct xfrm_dst *)dst)->path_cookie = rt->rt6i_node->fn_sernum;
 141
 142         *dst_p = dst;
 143         dst = dst_prev;
 144
 145         dst_prev = *dst_p;
 146         i = 0;
 147         for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
 148                 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
 149
 150                 dst_prev->xfrm = xfrm[i++];
 151                 dst_prev->dev = rt->u.dst.dev;
 152                 if (rt->u.dst.dev)
 153                         dev_hold(rt->u.dst.dev);
 154                 dst_prev->obsolete      = -1;
 155                 dst_prev->flags        |= DST_HOST;
 156                 dst_prev->lastuse       = jiffies;
 157                 dst_prev->header_len    = header_len;
 158                 dst_prev->trailer_len   = trailer_len;
 159                 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
 160
 161                 /* Copy neighbour for reachability confirmation */
 162                 dst_prev->neighbour     = neigh_clone(rt->u.dst.neighbour);
 163                 dst_prev->input         = rt->u.dst.input;
 164                 dst_prev->output        = xfrm6_output;
 165                 /* Sheit... I remember I did this right. Apparently,
 166                  * it was magically lost, so this code needs audit */
 167                 x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
 168                 x->u.rt6.rt6i_metric   = rt0->rt6i_metric;
 169                 x->u.rt6.rt6i_node     = rt0->rt6i_node;
 170                 x->u.rt6.rt6i_gateway  = rt0->rt6i_gateway;
 171                 memcpy(&x->u.rt6.rt6i_gateway, &rt0->rt6i_gateway, sizeof(x->u.rt6.rt6i_gateway));
 172                 x->u.rt6.rt6i_dst      = rt0->rt6i_dst;
 173                 x->u.rt6.rt6i_src      = rt0->rt6i_src;
 174                 x->u.rt6.rt6i_idev     = rt0->rt6i_idev;
 175                 in6_dev_hold(rt0->rt6i_idev);
 176                 header_len -= x->u.dst.xfrm->props.header_len;
 177                 trailer_len -= x->u.dst.xfrm->props.trailer_len;
 178         }
 179
 180         xfrm_init_pmtu(dst);
 181         return 0;
 182
 183 error:
 184         if (dst)
 185                 dst_free(dst);
 186         return err;
 187 }
 188
 189 static inline void
 190 _decode_session6(struct sk_buff *skb, struct flowi *fl)
 191 {
 192         u16 offset = skb->h.raw - skb->nh.raw;
 193         struct ipv6hdr *hdr = skb->nh.ipv6h;
 194         struct ipv6_opt_hdr *exthdr;
 195         u8 nexthdr = skb->nh.raw[IP6CB(skb)->nhoff];
 196
 197         memset(fl, 0, sizeof(struct flowi));
 198         ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
 199         ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
 200
 201         while (pskb_may_pull(skb, skb->nh.raw + offset + 1 - skb->data)) {
 202                 exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 203
 204                 switch (nexthdr) {
 205                 case NEXTHDR_ROUTING:
 206                 case NEXTHDR_HOP:
 207                 case NEXTHDR_DEST:
 208                         offset += ipv6_optlen(exthdr);
 209                         nexthdr = exthdr->nexthdr;
 210                         exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 211                         break;
 212
 213                 case IPPROTO_UDP:
 214                 case IPPROTO_TCP:
 215                 case IPPROTO_SCTP:
 216                 case IPPROTO_DCCP:
 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         xfrm6_policy_afinfo.garbage_collect();
 251         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
 252 }
 253
 254 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 255 {
 256         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 257         struct dst_entry *path = xdst->route;
 258
 259         path->ops->update_pmtu(path, mtu);
 260 }
 261
 262 static void xfrm6_dst_destroy(struct dst_entry *dst)
 263 {
 264         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 265
 266         if (likely(xdst->u.rt6.rt6i_idev))
 267                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 268         xfrm_dst_destroy(xdst);
 269 }
 270
 271 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 272                              int unregister)
 273 {
 274         struct xfrm_dst *xdst;
 275
 276         if (!unregister)
 277                 return;
 278
 279         xdst = (struct xfrm_dst *)dst;
 280         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 281                 struct inet6_dev *loopback_idev = in6_dev_get(&loopback_dev);
 282                 BUG_ON(!loopback_idev);
 283
 284                 do {
 285                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 286                         xdst->u.rt6.rt6i_idev = loopback_idev;
 287                         in6_dev_hold(loopback_idev);
 288                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 289                 } while (xdst->u.dst.xfrm);
 290
 291                 __in6_dev_put(loopback_idev);
 292         }
 293
 294         xfrm_dst_ifdown(dst, dev);
 295 }
 296
 297 static struct dst_ops xfrm6_dst_ops = {
 298         .family =               AF_INET6,
 299         .protocol =             __constant_htons(ETH_P_IPV6),
 300         .gc =                   xfrm6_garbage_collect,
 301         .update_pmtu =          xfrm6_update_pmtu,
 302         .destroy =              xfrm6_dst_destroy,
 303         .ifdown =               xfrm6_dst_ifdown,
 304         .gc_thresh =            1024,
 305         .entry_size =           sizeof(struct xfrm_dst),
 306 };
 307
 308 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 309         .family =               AF_INET6,
 310         .dst_ops =              &xfrm6_dst_ops,
 311         .dst_lookup =           xfrm6_dst_lookup,
 312         .find_bundle =          __xfrm6_find_bundle,
 313         .bundle_create =        __xfrm6_bundle_create,
 314         .decode_session =       _decode_session6,
 315 };
 316
 317 static void __init xfrm6_policy_init(void)
 318 {
 319         xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 320 }
 321
 322 static void xfrm6_policy_fini(void)
 323 {
 324         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 325 }
 326
 327 void __init xfrm6_init(void)
 328 {
 329         xfrm6_policy_init();
 330         xfrm6_state_init();
 331 }
 332
 333 void xfrm6_fini(void)
 334 {
 335         //xfrm6_input_fini();
 336         xfrm6_policy_fini();
 337         xfrm6_state_fini();
 338 }