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
 117                 dst1->next = dst_prev;
 118                 dst_prev = dst1;
 119                 if (xfrm[i]->props.mode) {
 120                         remote = (struct in6_addr*)&xfrm[i]->id.daddr;
 121                         local  = (struct in6_addr*)&xfrm[i]->props.saddr;
 122                         tunnel = 1;
 123                 }
 124                 header_len += xfrm[i]->props.header_len;
 125                 trailer_len += xfrm[i]->props.trailer_len;
 126
 127                 if (tunnel) {
 128                         ipv6_addr_copy(&fl_tunnel.fl6_dst, remote);
 129                         ipv6_addr_copy(&fl_tunnel.fl6_src, local);
 130                         err = xfrm_dst_lookup((struct xfrm_dst **) &rt,
 131                                               &fl_tunnel, AF_INET6);
 132                         if (err)
 133                                 goto error;
 134                 } else
 135                         dst_hold(&rt->u.dst);
 136         }
 137
 138         dst_prev->child = &rt->u.dst;
 139         dst->path = &rt->u.dst;
 140
 141         *dst_p = dst;
 142         dst = dst_prev;
 143
 144         dst_prev = *dst_p;
 145         i = 0;
 146         for (; dst_prev != &rt->u.dst; dst_prev = dst_prev->child) {
 147                 struct xfrm_dst *x = (struct xfrm_dst*)dst_prev;
 148
 149                 dst_prev->xfrm = xfrm[i++];
 150                 dst_prev->dev = rt->u.dst.dev;
 151                 if (rt->u.dst.dev)
 152                         dev_hold(rt->u.dst.dev);
 153                 dst_prev->obsolete      = -1;
 154                 dst_prev->flags        |= DST_HOST;
 155                 dst_prev->lastuse       = jiffies;
 156                 dst_prev->header_len    = header_len;
 157                 dst_prev->trailer_len   = trailer_len;
 158                 memcpy(&dst_prev->metrics, &x->route->metrics, sizeof(dst_prev->metrics));
 159
 160                 /* Copy neighbour for reachability confirmation */
 161                 dst_prev->neighbour     = neigh_clone(rt->u.dst.neighbour);
 162                 dst_prev->input         = rt->u.dst.input;
 163                 dst_prev->output        = xfrm6_output;
 164                 /* Sheit... I remember I did this right. Apparently,
 165                  * it was magically lost, so this code needs audit */
 166                 x->u.rt6.rt6i_flags    = rt0->rt6i_flags&(RTCF_BROADCAST|RTCF_MULTICAST|RTCF_LOCAL);
 167                 x->u.rt6.rt6i_metric   = rt0->rt6i_metric;
 168                 x->u.rt6.rt6i_node     = rt0->rt6i_node;
 169                 x->u.rt6.rt6i_gateway  = rt0->rt6i_gateway;
 170                 memcpy(&x->u.rt6.rt6i_gateway, &rt0->rt6i_gateway, sizeof(x->u.rt6.rt6i_gateway));
 171                 x->u.rt6.rt6i_dst      = rt0->rt6i_dst;
 172                 x->u.rt6.rt6i_src      = rt0->rt6i_src;
 173                 x->u.rt6.rt6i_idev     = rt0->rt6i_idev;
 174                 in6_dev_hold(rt0->rt6i_idev);
 175                 header_len -= x->u.dst.xfrm->props.header_len;
 176                 trailer_len -= x->u.dst.xfrm->props.trailer_len;
 177         }
 178
 179         xfrm_init_pmtu(dst);
 180         return 0;
 181
 182 error:
 183         if (dst)
 184                 dst_free(dst);
 185         return err;
 186 }
 187
 188 static inline void
 189 _decode_session6(struct sk_buff *skb, struct flowi *fl)
 190 {
 191         u16 offset = sizeof(struct ipv6hdr);
 192         struct ipv6hdr *hdr = skb->nh.ipv6h;
 193         struct ipv6_opt_hdr *exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 194         u8 nexthdr = skb->nh.ipv6h->nexthdr;
 195
 196         memset(fl, 0, sizeof(struct flowi));
 197         ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
 198         ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
 199
 200         while (pskb_may_pull(skb, skb->nh.raw + offset + 1 - skb->data)) {
 201                 switch (nexthdr) {
 202                 case NEXTHDR_ROUTING:
 203                 case NEXTHDR_HOP:
 204                 case NEXTHDR_DEST:
 205                         offset += ipv6_optlen(exthdr);
 206                         nexthdr = exthdr->nexthdr;
 207                         exthdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset);
 208                         break;
 209
 210                 case IPPROTO_UDP:
 211                 case IPPROTO_TCP:
 212                 case IPPROTO_SCTP:
 213                         if (pskb_may_pull(skb, skb->nh.raw + offset + 4 - skb->data)) {
 214                                 u16 *ports = (u16 *)exthdr;
 215
 216                                 fl->fl_ip_sport = ports[0];
 217                                 fl->fl_ip_dport = ports[1];
 218                         }
 219                         fl->proto = nexthdr;
 220                         return;
 221
 222                 case IPPROTO_ICMPV6:
 223                         if (pskb_may_pull(skb, skb->nh.raw + offset + 2 - skb->data)) {
 224                                 u8 *icmp = (u8 *)exthdr;
 225
 226                                 fl->fl_icmp_type = icmp[0];
 227                                 fl->fl_icmp_code = icmp[1];
 228                         }
 229                         fl->proto = nexthdr;
 230                         return;
 231
 232                 /* XXX Why are there these headers? */
 233                 case IPPROTO_AH:
 234                 case IPPROTO_ESP:
 235                 case IPPROTO_COMP:
 236                 default:
 237                         fl->fl_ipsec_spi = 0;
 238                         fl->proto = nexthdr;
 239                         return;
 240                 };
 241         }
 242 }
 243
 244 static inline int xfrm6_garbage_collect(void)
 245 {
 246         read_lock(&xfrm6_policy_afinfo.lock);
 247         xfrm6_policy_afinfo.garbage_collect();
 248         read_unlock(&xfrm6_policy_afinfo.lock);
 249         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
 250 }
 251
 252 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 253 {
 254         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 255         struct dst_entry *path = xdst->route;
 256
 257         path->ops->update_pmtu(path, mtu);
 258 }
 259
 260 static void xfrm6_dst_destroy(struct dst_entry *dst)
 261 {
 262         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 263
 264         if (likely(xdst->u.rt6.rt6i_idev))
 265                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 266         xfrm_dst_destroy(xdst);
 267 }
 268
 269 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 270                              int unregister)
 271 {
 272         struct xfrm_dst *xdst;
 273
 274         if (!unregister)
 275                 return;
 276
 277         xdst = (struct xfrm_dst *)dst;
 278         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 279                 struct inet6_dev *loopback_idev = in6_dev_get(&loopback_dev);
 280                 BUG_ON(!loopback_idev);
 281
 282                 do {
 283                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 284                         xdst->u.rt6.rt6i_idev = loopback_idev;
 285                         in6_dev_hold(loopback_idev);
 286                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 287                 } while (xdst->u.dst.xfrm);
 288
 289                 __in6_dev_put(loopback_idev);
 290         }
 291
 292         xfrm_dst_ifdown(dst, dev);
 293 }
 294
 295 static struct dst_ops xfrm6_dst_ops = {
 296         .family =               AF_INET6,
 297         .protocol =             __constant_htons(ETH_P_IPV6),
 298         .gc =                   xfrm6_garbage_collect,
 299         .update_pmtu =          xfrm6_update_pmtu,
 300         .destroy =              xfrm6_dst_destroy,
 301         .ifdown =               xfrm6_dst_ifdown,
 302         .gc_thresh =            1024,
 303         .entry_size =           sizeof(struct xfrm_dst),
 304 };
 305
 306 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 307         .family =               AF_INET6,
 308         .lock =                 RW_LOCK_UNLOCKED,
 309         .type_map =             &xfrm6_type_map,
 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 }