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 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(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(struct net *net,
  53                            xfrm_address_t *saddr, xfrm_address_t *daddr)
  54 {
  55         struct dst_entry *dst;
  56         struct net_device *dev;
  57
  58         dst = xfrm6_dst_lookup(net, 0, NULL, daddr);
  59         if (IS_ERR(dst))
  60                 return -EHOSTUNREACH;
  61
  62         dev = ip6_dst_idev(dst)->dev;
  63         ipv6_dev_get_saddr(dev_net(dev), dev,
  64                            (struct in6_addr *)&daddr->a6, 0,
  65                            (struct in6_addr *)&saddr->a6);
  66         dst_release(dst);
  67         return 0;
  68 }
  69
  70 static int xfrm6_get_tos(const struct flowi *fl)
  71 {
  72         return 0;
  73 }
  74
  75 static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
  76                            int nfheader_len)
  77 {
  78         if (dst->ops->family == AF_INET6) {
  79                 struct rt6_info *rt = (struct rt6_info*)dst;
  80                 if (rt->rt6i_node)
  81                         path->path_cookie = rt->rt6i_node->fn_sernum;
  82         }
  83
  84         path->u.rt6.rt6i_nfheader_len = nfheader_len;
  85
  86         return 0;
  87 }
  88
  89 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
  90                           const struct flowi *fl)
  91 {
  92         struct rt6_info *rt = (struct rt6_info*)xdst->route;
  93
  94         xdst->u.dst.dev = dev;
  95         dev_hold(dev);
  96
  97         xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
  98         if (!xdst->u.rt6.rt6i_idev)
  99                 return -ENODEV;
 100
 101         xdst->u.rt6.rt6i_peer = rt->rt6i_peer;
 102         if (rt->rt6i_peer)
 103                 atomic_inc(&rt->rt6i_peer->refcnt);
 104
 105         /* Sheit... I remember I did this right. Apparently,
 106          * it was magically lost, so this code needs audit */
 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         int onlyproto = 0;
 124         u16 offset = skb_network_header_len(skb);
 125         struct ipv6hdr *hdr = ipv6_hdr(skb);
 126         struct ipv6_opt_hdr *exthdr;
 127         const unsigned char *nh = skb_network_header(skb);
 128         u8 nexthdr = nh[IP6CB(skb)->nhoff];
 129
 130         memset(fl, 0, sizeof(struct flowi));
 131         fl->mark = skb->mark;
 132
 133         ipv6_addr_copy(&fl->fl6_dst, reverse ? &hdr->saddr : &hdr->daddr);
 134         ipv6_addr_copy(&fl->fl6_src, reverse ? &hdr->daddr : &hdr->saddr);
 135
 136         while (nh + offset + 1 < skb->data ||
 137                pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
 138                 nh = skb_network_header(skb);
 139                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 140
 141                 switch (nexthdr) {
 142                 case NEXTHDR_FRAGMENT:
 143                         onlyproto = 1;
 144                 case NEXTHDR_ROUTING:
 145                 case NEXTHDR_HOP:
 146                 case NEXTHDR_DEST:
 147                         offset += ipv6_optlen(exthdr);
 148                         nexthdr = exthdr->nexthdr;
 149                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 150                         break;
 151
 152                 case IPPROTO_UDP:
 153                 case IPPROTO_UDPLITE:
 154                 case IPPROTO_TCP:
 155                 case IPPROTO_SCTP:
 156                 case IPPROTO_DCCP:
 157                         if (!onlyproto && (nh + offset + 4 < skb->data ||
 158                              pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
 159                                 __be16 *ports = (__be16 *)exthdr;
 160
 161                                 fl->fl_ip_sport = ports[!!reverse];
 162                                 fl->fl_ip_dport = ports[!reverse];
 163                         }
 164                         fl->proto = nexthdr;
 165                         return;
 166
 167                 case IPPROTO_ICMPV6:
 168                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
 169                                 u8 *icmp = (u8 *)exthdr;
 170
 171                                 fl->fl_icmp_type = icmp[0];
 172                                 fl->fl_icmp_code = icmp[1];
 173                         }
 174                         fl->proto = nexthdr;
 175                         return;
 176
 177 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 178                 case IPPROTO_MH:
 179                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
 180                                 struct ip6_mh *mh;
 181                                 mh = (struct ip6_mh *)exthdr;
 182
 183                                 fl->fl_mh_type = mh->ip6mh_type;
 184                         }
 185                         fl->proto = nexthdr;
 186                         return;
 187 #endif
 188
 189                 /* XXX Why are there these headers? */
 190                 case IPPROTO_AH:
 191                 case IPPROTO_ESP:
 192                 case IPPROTO_COMP:
 193                 default:
 194                         fl->fl_ipsec_spi = 0;
 195                         fl->proto = nexthdr;
 196                         return;
 197                 }
 198         }
 199 }
 200
 201 static inline int xfrm6_garbage_collect(struct dst_ops *ops)
 202 {
 203         struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
 204
 205         xfrm6_policy_afinfo.garbage_collect(net);
 206         return dst_entries_get_fast(ops) > ops->gc_thresh * 2;
 207 }
 208
 209 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 210 {
 211         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 212         struct dst_entry *path = xdst->route;
 213
 214         path->ops->update_pmtu(path, mtu);
 215 }
 216
 217 static void xfrm6_dst_destroy(struct dst_entry *dst)
 218 {
 219         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 220
 221         if (likely(xdst->u.rt6.rt6i_idev))
 222                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 223         dst_destroy_metrics_generic(dst);
 224         if (likely(xdst->u.rt6.rt6i_peer))
 225                 inet_putpeer(xdst->u.rt6.rt6i_peer);
 226         xfrm_dst_destroy(xdst);
 227 }
 228
 229 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 230                              int unregister)
 231 {
 232         struct xfrm_dst *xdst;
 233
 234         if (!unregister)
 235                 return;
 236
 237         xdst = (struct xfrm_dst *)dst;
 238         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 239                 struct inet6_dev *loopback_idev =
 240                         in6_dev_get(dev_net(dev)->loopback_dev);
 241                 BUG_ON(!loopback_idev);
 242
 243                 do {
 244                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 245                         xdst->u.rt6.rt6i_idev = loopback_idev;
 246                         in6_dev_hold(loopback_idev);
 247                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 248                 } while (xdst->u.dst.xfrm);
 249
 250                 __in6_dev_put(loopback_idev);
 251         }
 252
 253         xfrm_dst_ifdown(dst, dev);
 254 }
 255
 256 static struct dst_ops xfrm6_dst_ops = {
 257         .family =               AF_INET6,
 258         .protocol =             cpu_to_be16(ETH_P_IPV6),
 259         .gc =                   xfrm6_garbage_collect,
 260         .update_pmtu =          xfrm6_update_pmtu,
 261         .cow_metrics =          dst_cow_metrics_generic,
 262         .destroy =              xfrm6_dst_destroy,
 263         .ifdown =               xfrm6_dst_ifdown,
 264         .local_out =            __ip6_local_out,
 265         .gc_thresh =            1024,
 266 };
 267
 268 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 269         .family =               AF_INET6,
 270         .dst_ops =              &xfrm6_dst_ops,
 271         .dst_lookup =           xfrm6_dst_lookup,
 272         .get_saddr =            xfrm6_get_saddr,
 273         .decode_session =       _decode_session6,
 274         .get_tos =              xfrm6_get_tos,
 275         .init_path =            xfrm6_init_path,
 276         .fill_dst =             xfrm6_fill_dst,
 277 };
 278
 279 static int __init xfrm6_policy_init(void)
 280 {
 281         return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 282 }
 283
 284 static void xfrm6_policy_fini(void)
 285 {
 286         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 287 }
 288
 289 #ifdef CONFIG_SYSCTL
 290 static struct ctl_table xfrm6_policy_table[] = {
 291         {
 292                 .procname       = "xfrm6_gc_thresh",
 293                 .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
 294                 .maxlen         = sizeof(int),
 295                 .mode           = 0644,
 296                 .proc_handler   = proc_dointvec,
 297         },
 298         { }
 299 };
 300
 301 static struct ctl_table_header *sysctl_hdr;
 302 #endif
 303
 304 int __init xfrm6_init(void)
 305 {
 306         int ret;
 307         unsigned int gc_thresh;
 308
 309         /*
 310          * We need a good default value for the xfrm6 gc threshold.
 311          * In ipv4 we set it to the route hash table size * 8, which
 312          * is half the size of the maximaum route cache for ipv4.  It
 313          * would be good to do the same thing for v6, except the table is
 314          * constructed differently here.  Here each table for a net namespace
 315          * can have FIB_TABLE_HASHSZ entries, so lets go with the same
 316          * computation that we used for ipv4 here.  Also, lets keep the initial
 317          * gc_thresh to a minimum of 1024, since, the ipv6 route cache defaults
 318          * to that as a minimum as well
 319          */
 320         gc_thresh = FIB6_TABLE_HASHSZ * 8;
 321         xfrm6_dst_ops.gc_thresh = (gc_thresh < 1024) ? 1024 : gc_thresh;
 322         dst_entries_init(&xfrm6_dst_ops);
 323
 324         ret = xfrm6_policy_init();
 325         if (ret) {
 326                 dst_entries_destroy(&xfrm6_dst_ops);
 327                 goto out;
 328         }
 329         ret = xfrm6_state_init();
 330         if (ret)
 331                 goto out_policy;
 332
 333 #ifdef CONFIG_SYSCTL
 334         sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv6_ctl_path,
 335                                                 xfrm6_policy_table);
 336 #endif
 337 out:
 338         return ret;
 339 out_policy:
 340         xfrm6_policy_fini();
 341         goto out;
 342 }
 343
 344 void xfrm6_fini(void)
 345 {
 346 #ifdef CONFIG_SYSCTL
 347         if (sysctl_hdr)
 348                 unregister_net_sysctl_table(sysctl_hdr);
 349 #endif
 350         //xfrm6_input_fini();
 351         xfrm6_policy_fini();
 352         xfrm6_state_fini();
 353         dst_entries_destroy(&xfrm6_dst_ops);
 354 }