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