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