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(struct net *net, int tos,
  31                                           xfrm_address_t *saddr,
  32                                           xfrm_address_t *daddr)
  33 {
  34         struct flowi fl = {};
  35         struct dst_entry *dst;
  36         int err;
  37
  38         memcpy(&fl.fl6_dst, daddr, sizeof(fl.fl6_dst));
  39         if (saddr)
  40                 memcpy(&fl.fl6_src, saddr, sizeof(fl.fl6_src));
  41
  42         dst = ip6_route_output(net, NULL, &fl);
  43
  44         err = dst->error;
  45         if (dst->error) {
  46                 dst_release(dst);
  47                 dst = ERR_PTR(err);
  48         }
  49
  50         return dst;
  51 }
  52
  53 static int xfrm6_get_saddr(xfrm_address_t *saddr, xfrm_address_t *daddr)
  54 {
  55         struct dst_entry *dst;
  56         struct net_device *dev;
  57
  58         dst = xfrm6_dst_lookup(&init_net, 0, NULL, daddr);
  59         if (IS_ERR(dst))
  60                 return -EHOSTUNREACH;
  61
  62         dev = ip6_dst_idev(dst)->dev;
  63         ipv6_dev_get_saddr(dev_net(dev), dev,
  64                            (struct in6_addr *)&daddr->a6, 0,
  65                            (struct in6_addr *)&saddr->a6);
  66         dst_release(dst);
  67         return 0;
  68 }
  69
  70 static struct dst_entry *
  71 __xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
  72 {
  73         struct dst_entry *dst;
  74
  75         /* Still not clear if we should set fl->fl6_{src,dst}... */
  76         read_lock_bh(&policy->lock);
  77         for (dst = policy->bundles; dst; dst = dst->next) {
  78                 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
  79                 struct in6_addr fl_dst_prefix, fl_src_prefix;
  80
  81                 ipv6_addr_prefix(&fl_dst_prefix,
  82                                  &fl->fl6_dst,
  83                                  xdst->u.rt6.rt6i_dst.plen);
  84                 ipv6_addr_prefix(&fl_src_prefix,
  85                                  &fl->fl6_src,
  86                                  xdst->u.rt6.rt6i_src.plen);
  87                 if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
  88                     ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
  89                     xfrm_bundle_ok(policy, xdst, fl, AF_INET6,
  90                                    (xdst->u.rt6.rt6i_dst.plen != 128 ||
  91                                     xdst->u.rt6.rt6i_src.plen != 128))) {
  92                         dst_clone(dst);
  93                         break;
  94                 }
  95         }
  96         read_unlock_bh(&policy->lock);
  97         return dst;
  98 }
  99
 100 static int xfrm6_get_tos(struct flowi *fl)
 101 {
 102         return 0;
 103 }
 104
 105 static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
 106                            int nfheader_len)
 107 {
 108         if (dst->ops->family == AF_INET6) {
 109                 struct rt6_info *rt = (struct rt6_info*)dst;
 110                 if (rt->rt6i_node)
 111                         path->path_cookie = rt->rt6i_node->fn_sernum;
 112         }
 113
 114         path->u.rt6.rt6i_nfheader_len = nfheader_len;
 115
 116         return 0;
 117 }
 118
 119 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev)
 120 {
 121         struct rt6_info *rt = (struct rt6_info*)xdst->route;
 122
 123         xdst->u.dst.dev = dev;
 124         dev_hold(dev);
 125
 126         xdst->u.rt6.rt6i_idev = in6_dev_get(rt->u.dst.dev);
 127         if (!xdst->u.rt6.rt6i_idev)
 128                 return -ENODEV;
 129
 130         /* Sheit... I remember I did this right. Apparently,
 131          * it was magically lost, so this code needs audit */
 132         xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
 133                                                    RTF_LOCAL);
 134         xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
 135         xdst->u.rt6.rt6i_node = rt->rt6i_node;
 136         if (rt->rt6i_node)
 137                 xdst->route_cookie = rt->rt6i_node->fn_sernum;
 138         xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
 139         xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
 140         xdst->u.rt6.rt6i_src = rt->rt6i_src;
 141
 142         return 0;
 143 }
 144
 145 static inline void
 146 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
 147 {
 148         int onlyproto = 0;
 149         u16 offset = skb_network_header_len(skb);
 150         struct ipv6hdr *hdr = ipv6_hdr(skb);
 151         struct ipv6_opt_hdr *exthdr;
 152         const unsigned char *nh = skb_network_header(skb);
 153         u8 nexthdr = nh[IP6CB(skb)->nhoff];
 154
 155         memset(fl, 0, sizeof(struct flowi));
 156         ipv6_addr_copy(&fl->fl6_dst, reverse ? &hdr->saddr : &hdr->daddr);
 157         ipv6_addr_copy(&fl->fl6_src, reverse ? &hdr->daddr : &hdr->saddr);
 158
 159         while (pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
 160                 nh = skb_network_header(skb);
 161                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 162
 163                 switch (nexthdr) {
 164                 case NEXTHDR_FRAGMENT:
 165                         onlyproto = 1;
 166                 case NEXTHDR_ROUTING:
 167                 case NEXTHDR_HOP:
 168                 case NEXTHDR_DEST:
 169                         offset += ipv6_optlen(exthdr);
 170                         nexthdr = exthdr->nexthdr;
 171                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 172                         break;
 173
 174                 case IPPROTO_UDP:
 175                 case IPPROTO_UDPLITE:
 176                 case IPPROTO_TCP:
 177                 case IPPROTO_SCTP:
 178                 case IPPROTO_DCCP:
 179                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 4 - skb->data)) {
 180                                 __be16 *ports = (__be16 *)exthdr;
 181
 182                                 fl->fl_ip_sport = ports[!!reverse];
 183                                 fl->fl_ip_dport = ports[!reverse];
 184                         }
 185                         fl->proto = nexthdr;
 186                         return;
 187
 188                 case IPPROTO_ICMPV6:
 189                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
 190                                 u8 *icmp = (u8 *)exthdr;
 191
 192                                 fl->fl_icmp_type = icmp[0];
 193                                 fl->fl_icmp_code = icmp[1];
 194                         }
 195                         fl->proto = nexthdr;
 196                         return;
 197
 198 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 199                 case IPPROTO_MH:
 200                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
 201                                 struct ip6_mh *mh;
 202                                 mh = (struct ip6_mh *)exthdr;
 203
 204                                 fl->fl_mh_type = mh->ip6mh_type;
 205                         }
 206                         fl->proto = nexthdr;
 207                         return;
 208 #endif
 209
 210                 /* XXX Why are there these headers? */
 211                 case IPPROTO_AH:
 212                 case IPPROTO_ESP:
 213                 case IPPROTO_COMP:
 214                 default:
 215                         fl->fl_ipsec_spi = 0;
 216                         fl->proto = nexthdr;
 217                         return;
 218                 }
 219         }
 220 }
 221
 222 static inline int xfrm6_garbage_collect(struct dst_ops *ops)
 223 {
 224         xfrm6_policy_afinfo.garbage_collect(&init_net);
 225         return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
 226 }
 227
 228 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 229 {
 230         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 231         struct dst_entry *path = xdst->route;
 232
 233         path->ops->update_pmtu(path, mtu);
 234 }
 235
 236 static void xfrm6_dst_destroy(struct dst_entry *dst)
 237 {
 238         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 239
 240         if (likely(xdst->u.rt6.rt6i_idev))
 241                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 242         xfrm_dst_destroy(xdst);
 243 }
 244
 245 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 246                              int unregister)
 247 {
 248         struct xfrm_dst *xdst;
 249
 250         if (!unregister)
 251                 return;
 252
 253         xdst = (struct xfrm_dst *)dst;
 254         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 255                 struct inet6_dev *loopback_idev =
 256                         in6_dev_get(dev_net(dev)->loopback_dev);
 257                 BUG_ON(!loopback_idev);
 258
 259                 do {
 260                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 261                         xdst->u.rt6.rt6i_idev = loopback_idev;
 262                         in6_dev_hold(loopback_idev);
 263                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 264                 } while (xdst->u.dst.xfrm);
 265
 266                 __in6_dev_put(loopback_idev);
 267         }
 268
 269         xfrm_dst_ifdown(dst, dev);
 270 }
 271
 272 static struct dst_ops xfrm6_dst_ops = {
 273         .family =               AF_INET6,
 274         .protocol =             __constant_htons(ETH_P_IPV6),
 275         .gc =                   xfrm6_garbage_collect,
 276         .update_pmtu =          xfrm6_update_pmtu,
 277         .destroy =              xfrm6_dst_destroy,
 278         .ifdown =               xfrm6_dst_ifdown,
 279         .local_out =            __ip6_local_out,
 280         .gc_thresh =            1024,
 281         .entries =              ATOMIC_INIT(0),
 282 };
 283
 284 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 285         .family =               AF_INET6,
 286         .dst_ops =              &xfrm6_dst_ops,
 287         .dst_lookup =           xfrm6_dst_lookup,
 288         .get_saddr =            xfrm6_get_saddr,
 289         .find_bundle =          __xfrm6_find_bundle,
 290         .decode_session =       _decode_session6,
 291         .get_tos =              xfrm6_get_tos,
 292         .init_path =            xfrm6_init_path,
 293         .fill_dst =             xfrm6_fill_dst,
 294 };
 295
 296 static int __init xfrm6_policy_init(void)
 297 {
 298         return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 299 }
 300
 301 static void xfrm6_policy_fini(void)
 302 {
 303         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 304 }
 305
 306 int __init xfrm6_init(void)
 307 {
 308         int ret;
 309
 310         ret = xfrm6_policy_init();
 311         if (ret)
 312                 goto out;
 313
 314         ret = xfrm6_state_init();
 315         if (ret)
 316                 goto out_policy;
 317 out:
 318         return ret;
 319 out_policy:
 320         xfrm6_policy_fini();
 321         goto out;
 322 }
 323
 324 void xfrm6_fini(void)
 325 {
 326         //xfrm6_input_fini();
 327         xfrm6_policy_fini();
 328         xfrm6_state_fini();
 329 }