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         xdst->u.rt6.rt6i_peer = rt->rt6i_peer;
 103         if (rt->rt6i_peer)
 104                 atomic_inc(&rt->rt6i_peer->refcnt);
 105
 106         /* Sheit... I remember I did this right. Apparently,
 107          * it was magically lost, so this code needs audit */
 108         xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
 109                                                    RTF_LOCAL);
 110         xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
 111         xdst->u.rt6.rt6i_node = rt->rt6i_node;
 112         if (rt->rt6i_node)
 113                 xdst->route_cookie = rt->rt6i_node->fn_sernum;
 114         xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
 115         xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
 116         xdst->u.rt6.rt6i_src = rt->rt6i_src;
 117
 118         return 0;
 119 }
 120
 121 static inline void
 122 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
 123 {
 124         struct flowi6 *fl6 = &fl->u.ip6;
 125         int onlyproto = 0;
 126         u16 offset = skb_network_header_len(skb);
 127         const struct ipv6hdr *hdr = ipv6_hdr(skb);
 128         struct ipv6_opt_hdr *exthdr;
 129         const unsigned char *nh = skb_network_header(skb);
 130         u8 nexthdr = nh[IP6CB(skb)->nhoff];
 131
 132         memset(fl6, 0, sizeof(struct flowi6));
 133         fl6->flowi6_mark = skb->mark;
 134
 135         fl6->daddr = reverse ? hdr->saddr : hdr->daddr;
 136         fl6->saddr = reverse ? hdr->daddr : hdr->saddr;
 137
 138         while (nh + offset + 1 < skb->data ||
 139                pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
 140                 nh = skb_network_header(skb);
 141                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 142
 143                 switch (nexthdr) {
 144                 case NEXTHDR_FRAGMENT:
 145                         onlyproto = 1;
 146                 case NEXTHDR_ROUTING:
 147                 case NEXTHDR_HOP:
 148                 case NEXTHDR_DEST:
 149                         offset += ipv6_optlen(exthdr);
 150                         nexthdr = exthdr->nexthdr;
 151                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 152                         break;
 153
 154                 case IPPROTO_UDP:
 155                 case IPPROTO_UDPLITE:
 156                 case IPPROTO_TCP:
 157                 case IPPROTO_SCTP:
 158                 case IPPROTO_DCCP:
 159                         if (!onlyproto && (nh + offset + 4 < skb->data ||
 160                              pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
 161                                 __be16 *ports = (__be16 *)exthdr;
 162
 163                                 fl6->fl6_sport = ports[!!reverse];
 164                                 fl6->fl6_dport = ports[!reverse];
 165                         }
 166                         fl6->flowi6_proto = nexthdr;
 167                         return;
 168
 169                 case IPPROTO_ICMPV6:
 170                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
 171                                 u8 *icmp = (u8 *)exthdr;
 172
 173                                 fl6->fl6_icmp_type = icmp[0];
 174                                 fl6->fl6_icmp_code = icmp[1];
 175                         }
 176                         fl6->flowi6_proto = nexthdr;
 177                         return;
 178
 179 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 180                 case IPPROTO_MH:
 181                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
 182                                 struct ip6_mh *mh;
 183                                 mh = (struct ip6_mh *)exthdr;
 184
 185                                 fl6->fl6_mh_type = mh->ip6mh_type;
 186                         }
 187                         fl6->flowi6_proto = nexthdr;
 188                         return;
 189 #endif
 190
 191                 /* XXX Why are there these headers? */
 192                 case IPPROTO_AH:
 193                 case IPPROTO_ESP:
 194                 case IPPROTO_COMP:
 195                 default:
 196                         fl6->fl6_ipsec_spi = 0;
 197                         fl6->flowi6_proto = nexthdr;
 198                         return;
 199                 }
 200         }
 201 }
 202
 203 static inline int xfrm6_garbage_collect(struct dst_ops *ops)
 204 {
 205         struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
 206
 207         xfrm6_policy_afinfo.garbage_collect(net);
 208         return dst_entries_get_fast(ops) > ops->gc_thresh * 2;
 209 }
 210
 211 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 212 {
 213         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 214         struct dst_entry *path = xdst->route;
 215
 216         path->ops->update_pmtu(path, mtu);
 217 }
 218
 219 static void xfrm6_dst_destroy(struct dst_entry *dst)
 220 {
 221         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 222
 223         if (likely(xdst->u.rt6.rt6i_idev))
 224                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 225         dst_destroy_metrics_generic(dst);
 226         if (likely(xdst->u.rt6.rt6i_peer))
 227                 inet_putpeer(xdst->u.rt6.rt6i_peer);
 228         xfrm_dst_destroy(xdst);
 229 }
 230
 231 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 232                              int unregister)
 233 {
 234         struct xfrm_dst *xdst;
 235
 236         if (!unregister)
 237                 return;
 238
 239         xdst = (struct xfrm_dst *)dst;
 240         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 241                 struct inet6_dev *loopback_idev =
 242                         in6_dev_get(dev_net(dev)->loopback_dev);
 243                 BUG_ON(!loopback_idev);
 244
 245                 do {
 246                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 247                         xdst->u.rt6.rt6i_idev = loopback_idev;
 248                         in6_dev_hold(loopback_idev);
 249                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 250                 } while (xdst->u.dst.xfrm);
 251
 252                 __in6_dev_put(loopback_idev);
 253         }
 254
 255         xfrm_dst_ifdown(dst, dev);
 256 }
 257
 258 static struct dst_ops xfrm6_dst_ops = {
 259         .family =               AF_INET6,
 260         .protocol =             cpu_to_be16(ETH_P_IPV6),
 261         .gc =                   xfrm6_garbage_collect,
 262         .update_pmtu =          xfrm6_update_pmtu,
 263         .cow_metrics =          dst_cow_metrics_generic,
 264         .destroy =              xfrm6_dst_destroy,
 265         .ifdown =               xfrm6_dst_ifdown,
 266         .local_out =            __ip6_local_out,
 267         .gc_thresh =            1024,
 268 };
 269
 270 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 271         .family =               AF_INET6,
 272         .dst_ops =              &xfrm6_dst_ops,
 273         .dst_lookup =           xfrm6_dst_lookup,
 274         .get_saddr =            xfrm6_get_saddr,
 275         .decode_session =       _decode_session6,
 276         .get_tos =              xfrm6_get_tos,
 277         .init_path =            xfrm6_init_path,
 278         .fill_dst =             xfrm6_fill_dst,
 279         .blackhole_route =      ip6_blackhole_route,
 280 };
 281
 282 static int __init xfrm6_policy_init(void)
 283 {
 284         return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 285 }
 286
 287 static void xfrm6_policy_fini(void)
 288 {
 289         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 290 }
 291
 292 #ifdef CONFIG_SYSCTL
 293 static struct ctl_table xfrm6_policy_table[] = {
 294         {
 295                 .procname       = "xfrm6_gc_thresh",
 296                 .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
 297                 .maxlen         = sizeof(int),
 298                 .mode           = 0644,
 299                 .proc_handler   = proc_dointvec,
 300         },
 301         { }
 302 };
 303
 304 static struct ctl_table_header *sysctl_hdr;
 305 #endif
 306
 307 int __init xfrm6_init(void)
 308 {
 309         int ret;
 310         unsigned int gc_thresh;
 311
 312         /*
 313          * We need a good default value for the xfrm6 gc threshold.
 314          * In ipv4 we set it to the route hash table size * 8, which
 315          * is half the size of the maximaum route cache for ipv4.  It
 316          * would be good to do the same thing for v6, except the table is
 317          * constructed differently here.  Here each table for a net namespace
 318          * can have FIB_TABLE_HASHSZ entries, so lets go with the same
 319          * computation that we used for ipv4 here.  Also, lets keep the initial
 320          * gc_thresh to a minimum of 1024, since, the ipv6 route cache defaults
 321          * to that as a minimum as well
 322          */
 323         gc_thresh = FIB6_TABLE_HASHSZ * 8;
 324         xfrm6_dst_ops.gc_thresh = (gc_thresh < 1024) ? 1024 : gc_thresh;
 325         dst_entries_init(&xfrm6_dst_ops);
 326
 327         ret = xfrm6_policy_init();
 328         if (ret) {
 329                 dst_entries_destroy(&xfrm6_dst_ops);
 330                 goto out;
 331         }
 332         ret = xfrm6_state_init();
 333         if (ret)
 334                 goto out_policy;
 335
 336 #ifdef CONFIG_SYSCTL
 337         sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv6_ctl_path,
 338                                                 xfrm6_policy_table);
 339 #endif
 340 out:
 341         return ret;
 342 out_policy:
 343         xfrm6_policy_fini();
 344         goto out;
 345 }
 346
 347 void xfrm6_fini(void)
 348 {
 349 #ifdef CONFIG_SYSCTL
 350         if (sysctl_hdr)
 351                 unregister_net_sysctl_table(sysctl_hdr);
 352 #endif
 353         //xfrm6_input_fini();
 354         xfrm6_policy_fini();
 355         xfrm6_state_fini();
 356         dst_entries_destroy(&xfrm6_dst_ops);
 357 }