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 xfrm_policy_afinfo xfrm6_policy_afinfo;
  28
  29 static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos,
  30                                           const xfrm_address_t *saddr,
  31                                           const xfrm_address_t *daddr)
  32 {
  33         struct flowi6 fl6;
  34         struct dst_entry *dst;
  35         int err;
  36
  37         memset(&fl6, 0, sizeof(fl6));
  38         memcpy(&fl6.daddr, daddr, sizeof(fl6.daddr));
  39         if (saddr)
  40                 memcpy(&fl6.saddr, saddr, sizeof(fl6.saddr));
  41
  42         dst = ip6_route_output(net, NULL, &fl6);
  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(struct net *net,
  54                            xfrm_address_t *saddr, xfrm_address_t *daddr)
  55 {
  56         struct dst_entry *dst;
  57         struct net_device *dev;
  58
  59         dst = xfrm6_dst_lookup(net, 0, NULL, daddr);
  60         if (IS_ERR(dst))
  61                 return -EHOSTUNREACH;
  62
  63         dev = ip6_dst_idev(dst)->dev;
  64         ipv6_dev_get_saddr(dev_net(dev), dev,
  65                            (struct in6_addr *)&daddr->a6, 0,
  66                            (struct in6_addr *)&saddr->a6);
  67         dst_release(dst);
  68         return 0;
  69 }
  70
  71 static int xfrm6_get_tos(const struct flowi *fl)
  72 {
  73         return 0;
  74 }
  75
  76 static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
  77                            int nfheader_len)
  78 {
  79         if (dst->ops->family == AF_INET6) {
  80                 struct rt6_info *rt = (struct rt6_info*)dst;
  81                 if (rt->rt6i_node)
  82                         path->path_cookie = rt->rt6i_node->fn_sernum;
  83         }
  84
  85         path->u.rt6.rt6i_nfheader_len = nfheader_len;
  86
  87         return 0;
  88 }
  89
  90 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
  91                           const struct flowi *fl)
  92 {
  93         struct rt6_info *rt = (struct rt6_info*)xdst->route;
  94
  95         xdst->u.dst.dev = dev;
  96         dev_hold(dev);
  97
  98         xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
  99         if (!xdst->u.rt6.rt6i_idev)
 100                 return -ENODEV;
 101
 102         rt6_transfer_peer(&xdst->u.rt6, rt);
 103
 104         /* Sheit... I remember I did this right. Apparently,
 105          * it was magically lost, so this code needs audit */
 106         xdst->u.rt6.n = neigh_clone(rt->n);
 107         xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
 108                                                    RTF_LOCAL);
 109         xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
 110         xdst->u.rt6.rt6i_node = rt->rt6i_node;
 111         if (rt->rt6i_node)
 112                 xdst->route_cookie = rt->rt6i_node->fn_sernum;
 113         xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
 114         xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
 115         xdst->u.rt6.rt6i_src = rt->rt6i_src;
 116
 117         return 0;
 118 }
 119
 120 static inline void
 121 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
 122 {
 123         struct flowi6 *fl6 = &fl->u.ip6;
 124         int onlyproto = 0;
 125         u16 offset = skb_network_header_len(skb);
 126         const struct ipv6hdr *hdr = ipv6_hdr(skb);
 127         struct ipv6_opt_hdr *exthdr;
 128         const unsigned char *nh = skb_network_header(skb);
 129         u8 nexthdr = nh[IP6CB(skb)->nhoff];
 130
 131         memset(fl6, 0, sizeof(struct flowi6));
 132         fl6->flowi6_mark = skb->mark;
 133
 134         fl6->daddr = reverse ? hdr->saddr : hdr->daddr;
 135         fl6->saddr = reverse ? hdr->daddr : hdr->saddr;
 136
 137         while (nh + offset + 1 < skb->data ||
 138                pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
 139                 nh = skb_network_header(skb);
 140                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 141
 142                 switch (nexthdr) {
 143                 case NEXTHDR_FRAGMENT:
 144                         onlyproto = 1;
 145                 case NEXTHDR_ROUTING:
 146                 case NEXTHDR_HOP:
 147                 case NEXTHDR_DEST:
 148                         offset += ipv6_optlen(exthdr);
 149                         nexthdr = exthdr->nexthdr;
 150                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 151                         break;
 152
 153                 case IPPROTO_UDP:
 154                 case IPPROTO_UDPLITE:
 155                 case IPPROTO_TCP:
 156                 case IPPROTO_SCTP:
 157                 case IPPROTO_DCCP:
 158                         if (!onlyproto && (nh + offset + 4 < skb->data ||
 159                              pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
 160                                 __be16 *ports = (__be16 *)exthdr;
 161
 162                                 fl6->fl6_sport = ports[!!reverse];
 163                                 fl6->fl6_dport = ports[!reverse];
 164                         }
 165                         fl6->flowi6_proto = nexthdr;
 166                         return;
 167
 168                 case IPPROTO_ICMPV6:
 169                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
 170                                 u8 *icmp = (u8 *)exthdr;
 171
 172                                 fl6->fl6_icmp_type = icmp[0];
 173                                 fl6->fl6_icmp_code = icmp[1];
 174                         }
 175                         fl6->flowi6_proto = nexthdr;
 176                         return;
 177
 178 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 179                 case IPPROTO_MH:
 180                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
 181                                 struct ip6_mh *mh;
 182                                 mh = (struct ip6_mh *)exthdr;
 183
 184                                 fl6->fl6_mh_type = mh->ip6mh_type;
 185                         }
 186                         fl6->flowi6_proto = nexthdr;
 187                         return;
 188 #endif
 189
 190                 /* XXX Why are there these headers? */
 191                 case IPPROTO_AH:
 192                 case IPPROTO_ESP:
 193                 case IPPROTO_COMP:
 194                 default:
 195                         fl6->fl6_ipsec_spi = 0;
 196                         fl6->flowi6_proto = nexthdr;
 197                         return;
 198                 }
 199         }
 200 }
 201
 202 static inline int xfrm6_garbage_collect(struct dst_ops *ops)
 203 {
 204         struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
 205
 206         xfrm6_policy_afinfo.garbage_collect(net);
 207         return dst_entries_get_fast(ops) > ops->gc_thresh * 2;
 208 }
 209
 210 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 211 {
 212         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 213         struct dst_entry *path = xdst->route;
 214
 215         path->ops->update_pmtu(path, mtu);
 216 }
 217
 218 static void xfrm6_redirect(struct dst_entry *dst, struct sk_buff *skb)
 219 {
 220         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 221         struct dst_entry *path = xdst->route;
 222
 223         path->ops->redirect(path, skb);
 224 }
 225
 226 static void xfrm6_dst_destroy(struct dst_entry *dst)
 227 {
 228         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 229
 230         if (likely(xdst->u.rt6.rt6i_idev))
 231                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 232         dst_destroy_metrics_generic(dst);
 233         if (rt6_has_peer(&xdst->u.rt6)) {
 234                 struct inet_peer *peer = rt6_peer_ptr(&xdst->u.rt6);
 235                 inet_putpeer(peer);
 236         }
 237         xfrm_dst_destroy(xdst);
 238 }
 239
 240 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 241                              int unregister)
 242 {
 243         struct xfrm_dst *xdst;
 244
 245         if (!unregister)
 246                 return;
 247
 248         xdst = (struct xfrm_dst *)dst;
 249         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 250                 struct inet6_dev *loopback_idev =
 251                         in6_dev_get(dev_net(dev)->loopback_dev);
 252                 BUG_ON(!loopback_idev);
 253
 254                 do {
 255                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 256                         xdst->u.rt6.rt6i_idev = loopback_idev;
 257                         in6_dev_hold(loopback_idev);
 258                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 259                 } while (xdst->u.dst.xfrm);
 260
 261                 __in6_dev_put(loopback_idev);
 262         }
 263
 264         xfrm_dst_ifdown(dst, dev);
 265 }
 266
 267 static struct dst_ops xfrm6_dst_ops = {
 268         .family =               AF_INET6,
 269         .protocol =             cpu_to_be16(ETH_P_IPV6),
 270         .gc =                   xfrm6_garbage_collect,
 271         .update_pmtu =          xfrm6_update_pmtu,
 272         .redirect =             xfrm6_redirect,
 273         .cow_metrics =          dst_cow_metrics_generic,
 274         .destroy =              xfrm6_dst_destroy,
 275         .ifdown =               xfrm6_dst_ifdown,
 276         .local_out =            __ip6_local_out,
 277         .gc_thresh =            1024,
 278 };
 279
 280 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 281         .family =               AF_INET6,
 282         .dst_ops =              &xfrm6_dst_ops,
 283         .dst_lookup =           xfrm6_dst_lookup,
 284         .get_saddr =            xfrm6_get_saddr,
 285         .decode_session =       _decode_session6,
 286         .get_tos =              xfrm6_get_tos,
 287         .init_path =            xfrm6_init_path,
 288         .fill_dst =             xfrm6_fill_dst,
 289         .blackhole_route =      ip6_blackhole_route,
 290 };
 291
 292 static int __init xfrm6_policy_init(void)
 293 {
 294         return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 295 }
 296
 297 static void xfrm6_policy_fini(void)
 298 {
 299         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 300 }
 301
 302 #ifdef CONFIG_SYSCTL
 303 static struct ctl_table xfrm6_policy_table[] = {
 304         {
 305                 .procname       = "xfrm6_gc_thresh",
 306                 .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
 307                 .maxlen         = sizeof(int),
 308                 .mode           = 0644,
 309                 .proc_handler   = proc_dointvec,
 310         },
 311         { }
 312 };
 313
 314 static struct ctl_table_header *sysctl_hdr;
 315 #endif
 316
 317 int __init xfrm6_init(void)
 318 {
 319         int ret;
 320         unsigned int gc_thresh;
 321
 322         /*
 323          * We need a good default value for the xfrm6 gc threshold.
 324          * In ipv4 we set it to the route hash table size * 8, which
 325          * is half the size of the maximaum route cache for ipv4.  It
 326          * would be good to do the same thing for v6, except the table is
 327          * constructed differently here.  Here each table for a net namespace
 328          * can have FIB_TABLE_HASHSZ entries, so lets go with the same
 329          * computation that we used for ipv4 here.  Also, lets keep the initial
 330          * gc_thresh to a minimum of 1024, since, the ipv6 route cache defaults
 331          * to that as a minimum as well
 332          */
 333         gc_thresh = FIB6_TABLE_HASHSZ * 8;
 334         xfrm6_dst_ops.gc_thresh = (gc_thresh < 1024) ? 1024 : gc_thresh;
 335         dst_entries_init(&xfrm6_dst_ops);
 336
 337         ret = xfrm6_policy_init();
 338         if (ret) {
 339                 dst_entries_destroy(&xfrm6_dst_ops);
 340                 goto out;
 341         }
 342         ret = xfrm6_state_init();
 343         if (ret)
 344                 goto out_policy;
 345
 346 #ifdef CONFIG_SYSCTL
 347         sysctl_hdr = register_net_sysctl(&init_net, "net/ipv6",
 348                                          xfrm6_policy_table);
 349 #endif
 350 out:
 351         return ret;
 352 out_policy:
 353         xfrm6_policy_fini();
 354         goto out;
 355 }
 356
 357 void xfrm6_fini(void)
 358 {
 359 #ifdef CONFIG_SYSCTL
 360         if (sysctl_hdr)
 361                 unregister_net_sysctl_table(sysctl_hdr);
 362 #endif
 363         //xfrm6_input_fini();
 364         xfrm6_policy_fini();
 365         xfrm6_state_fini();
 366         dst_entries_destroy(&xfrm6_dst_ops);
 367 }