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                                           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(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(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                           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         /* Sheit... I remember I did this right. Apparently,
 102          * it was magically lost, so this code needs audit */
 103         xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
 104                                                    RTF_LOCAL);
 105         xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
 106         xdst->u.rt6.rt6i_node = rt->rt6i_node;
 107         if (rt->rt6i_node)
 108                 xdst->route_cookie = rt->rt6i_node->fn_sernum;
 109         xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
 110         xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
 111         xdst->u.rt6.rt6i_src = rt->rt6i_src;
 112
 113         return 0;
 114 }
 115
 116 static inline void
 117 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
 118 {
 119         int onlyproto = 0;
 120         u16 offset = skb_network_header_len(skb);
 121         struct ipv6hdr *hdr = ipv6_hdr(skb);
 122         struct ipv6_opt_hdr *exthdr;
 123         const unsigned char *nh = skb_network_header(skb);
 124         u8 nexthdr = nh[IP6CB(skb)->nhoff];
 125
 126         memset(fl, 0, sizeof(struct flowi));
 127         ipv6_addr_copy(&fl->fl6_dst, reverse ? &hdr->saddr : &hdr->daddr);
 128         ipv6_addr_copy(&fl->fl6_src, reverse ? &hdr->daddr : &hdr->saddr);
 129
 130         while (nh + offset + 1 < skb->data ||
 131                pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
 132                 nh = skb_network_header(skb);
 133                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 134
 135                 switch (nexthdr) {
 136                 case NEXTHDR_FRAGMENT:
 137                         onlyproto = 1;
 138                 case NEXTHDR_ROUTING:
 139                 case NEXTHDR_HOP:
 140                 case NEXTHDR_DEST:
 141                         offset += ipv6_optlen(exthdr);
 142                         nexthdr = exthdr->nexthdr;
 143                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 144                         break;
 145
 146                 case IPPROTO_UDP:
 147                 case IPPROTO_UDPLITE:
 148                 case IPPROTO_TCP:
 149                 case IPPROTO_SCTP:
 150                 case IPPROTO_DCCP:
 151                         if (!onlyproto && (nh + offset + 4 < skb->data ||
 152                              pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
 153                                 __be16 *ports = (__be16 *)exthdr;
 154
 155                                 fl->fl_ip_sport = ports[!!reverse];
 156                                 fl->fl_ip_dport = ports[!reverse];
 157                         }
 158                         fl->proto = nexthdr;
 159                         return;
 160
 161                 case IPPROTO_ICMPV6:
 162                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
 163                                 u8 *icmp = (u8 *)exthdr;
 164
 165                                 fl->fl_icmp_type = icmp[0];
 166                                 fl->fl_icmp_code = icmp[1];
 167                         }
 168                         fl->proto = nexthdr;
 169                         return;
 170
 171 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 172                 case IPPROTO_MH:
 173                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
 174                                 struct ip6_mh *mh;
 175                                 mh = (struct ip6_mh *)exthdr;
 176
 177                                 fl->fl_mh_type = mh->ip6mh_type;
 178                         }
 179                         fl->proto = nexthdr;
 180                         return;
 181 #endif
 182
 183                 /* XXX Why are there these headers? */
 184                 case IPPROTO_AH:
 185                 case IPPROTO_ESP:
 186                 case IPPROTO_COMP:
 187                 default:
 188                         fl->fl_ipsec_spi = 0;
 189                         fl->proto = nexthdr;
 190                         return;
 191                 }
 192         }
 193 }
 194
 195 static inline int xfrm6_garbage_collect(struct dst_ops *ops)
 196 {
 197         struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
 198
 199         xfrm6_policy_afinfo.garbage_collect(net);
 200         return (atomic_read(&ops->entries) > ops->gc_thresh * 2);
 201 }
 202
 203 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 204 {
 205         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 206         struct dst_entry *path = xdst->route;
 207
 208         path->ops->update_pmtu(path, mtu);
 209 }
 210
 211 static void xfrm6_dst_destroy(struct dst_entry *dst)
 212 {
 213         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 214
 215         if (likely(xdst->u.rt6.rt6i_idev))
 216                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 217         xfrm_dst_destroy(xdst);
 218 }
 219
 220 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 221                              int unregister)
 222 {
 223         struct xfrm_dst *xdst;
 224
 225         if (!unregister)
 226                 return;
 227
 228         xdst = (struct xfrm_dst *)dst;
 229         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 230                 struct inet6_dev *loopback_idev =
 231                         in6_dev_get(dev_net(dev)->loopback_dev);
 232                 BUG_ON(!loopback_idev);
 233
 234                 do {
 235                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 236                         xdst->u.rt6.rt6i_idev = loopback_idev;
 237                         in6_dev_hold(loopback_idev);
 238                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 239                 } while (xdst->u.dst.xfrm);
 240
 241                 __in6_dev_put(loopback_idev);
 242         }
 243
 244         xfrm_dst_ifdown(dst, dev);
 245 }
 246
 247 static struct dst_ops xfrm6_dst_ops = {
 248         .family =               AF_INET6,
 249         .protocol =             cpu_to_be16(ETH_P_IPV6),
 250         .gc =                   xfrm6_garbage_collect,
 251         .update_pmtu =          xfrm6_update_pmtu,
 252         .destroy =              xfrm6_dst_destroy,
 253         .ifdown =               xfrm6_dst_ifdown,
 254         .local_out =            __ip6_local_out,
 255         .gc_thresh =            1024,
 256         .entries =              ATOMIC_INIT(0),
 257 };
 258
 259 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 260         .family =               AF_INET6,
 261         .dst_ops =              &xfrm6_dst_ops,
 262         .dst_lookup =           xfrm6_dst_lookup,
 263         .get_saddr =            xfrm6_get_saddr,
 264         .decode_session =       _decode_session6,
 265         .get_tos =              xfrm6_get_tos,
 266         .init_path =            xfrm6_init_path,
 267         .fill_dst =             xfrm6_fill_dst,
 268 };
 269
 270 static int __init xfrm6_policy_init(void)
 271 {
 272         return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 273 }
 274
 275 static void xfrm6_policy_fini(void)
 276 {
 277         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 278 }
 279
 280 #ifdef CONFIG_SYSCTL
 281 static struct ctl_table xfrm6_policy_table[] = {
 282         {
 283                 .procname       = "xfrm6_gc_thresh",
 284                 .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
 285                 .maxlen         = sizeof(int),
 286                 .mode           = 0644,
 287                 .proc_handler   = proc_dointvec,
 288         },
 289         { }
 290 };
 291
 292 static struct ctl_table_header *sysctl_hdr;
 293 #endif
 294
 295 int __init xfrm6_init(void)
 296 {
 297         int ret;
 298         unsigned int gc_thresh;
 299
 300         /*
 301          * We need a good default value for the xfrm6 gc threshold.
 302          * In ipv4 we set it to the route hash table size * 8, which
 303          * is half the size of the maximaum route cache for ipv4.  It
 304          * would be good to do the same thing for v6, except the table is
 305          * constructed differently here.  Here each table for a net namespace
 306          * can have FIB_TABLE_HASHSZ entries, so lets go with the same
 307          * computation that we used for ipv4 here.  Also, lets keep the initial
 308          * gc_thresh to a minimum of 1024, since, the ipv6 route cache defaults
 309          * to that as a minimum as well
 310          */
 311         gc_thresh = FIB6_TABLE_HASHSZ * 8;
 312         xfrm6_dst_ops.gc_thresh = (gc_thresh < 1024) ? 1024 : gc_thresh;
 313
 314         ret = xfrm6_policy_init();
 315         if (ret)
 316                 goto out;
 317
 318         ret = xfrm6_state_init();
 319         if (ret)
 320                 goto out_policy;
 321
 322 #ifdef CONFIG_SYSCTL
 323         sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv6_ctl_path,
 324                                                 xfrm6_policy_table);
 325 #endif
 326 out:
 327         return ret;
 328 out_policy:
 329         xfrm6_policy_fini();
 330         goto out;
 331 }
 332
 333 void xfrm6_fini(void)
 334 {
 335 #ifdef CONFIG_SYSCTL
 336         if (sysctl_hdr)
 337                 unregister_net_sysctl_table(sysctl_hdr);
 338 #endif
 339         //xfrm6_input_fini();
 340         xfrm6_policy_fini();
 341         xfrm6_state_fini();
 342 }