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