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         fl->mark = skb->mark;
 128
 129         ipv6_addr_copy(&fl->fl6_dst, reverse ? &hdr->saddr : &hdr->daddr);
 130         ipv6_addr_copy(&fl->fl6_src, reverse ? &hdr->daddr : &hdr->saddr);
 131
 132         while (nh + offset + 1 < skb->data ||
 133                pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
 134                 nh = skb_network_header(skb);
 135                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 136
 137                 switch (nexthdr) {
 138                 case NEXTHDR_FRAGMENT:
 139                         onlyproto = 1;
 140                 case NEXTHDR_ROUTING:
 141                 case NEXTHDR_HOP:
 142                 case NEXTHDR_DEST:
 143                         offset += ipv6_optlen(exthdr);
 144                         nexthdr = exthdr->nexthdr;
 145                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 146                         break;
 147
 148                 case IPPROTO_UDP:
 149                 case IPPROTO_UDPLITE:
 150                 case IPPROTO_TCP:
 151                 case IPPROTO_SCTP:
 152                 case IPPROTO_DCCP:
 153                         if (!onlyproto && (nh + offset + 4 < skb->data ||
 154                              pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
 155                                 __be16 *ports = (__be16 *)exthdr;
 156
 157                                 fl->fl_ip_sport = ports[!!reverse];
 158                                 fl->fl_ip_dport = ports[!reverse];
 159                         }
 160                         fl->proto = nexthdr;
 161                         return;
 162
 163                 case IPPROTO_ICMPV6:
 164                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
 165                                 u8 *icmp = (u8 *)exthdr;
 166
 167                                 fl->fl_icmp_type = icmp[0];
 168                                 fl->fl_icmp_code = icmp[1];
 169                         }
 170                         fl->proto = nexthdr;
 171                         return;
 172
 173 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 174                 case IPPROTO_MH:
 175                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
 176                                 struct ip6_mh *mh;
 177                                 mh = (struct ip6_mh *)exthdr;
 178
 179                                 fl->fl_mh_type = mh->ip6mh_type;
 180                         }
 181                         fl->proto = nexthdr;
 182                         return;
 183 #endif
 184
 185                 /* XXX Why are there these headers? */
 186                 case IPPROTO_AH:
 187                 case IPPROTO_ESP:
 188                 case IPPROTO_COMP:
 189                 default:
 190                         fl->fl_ipsec_spi = 0;
 191                         fl->proto = nexthdr;
 192                         return;
 193                 }
 194         }
 195 }
 196
 197 static inline int xfrm6_garbage_collect(struct dst_ops *ops)
 198 {
 199         struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
 200
 201         xfrm6_policy_afinfo.garbage_collect(net);
 202         return (atomic_read(&ops->entries) > ops->gc_thresh * 2);
 203 }
 204
 205 static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 206 {
 207         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 208         struct dst_entry *path = xdst->route;
 209
 210         path->ops->update_pmtu(path, mtu);
 211 }
 212
 213 static void xfrm6_dst_destroy(struct dst_entry *dst)
 214 {
 215         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 216
 217         if (likely(xdst->u.rt6.rt6i_idev))
 218                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 219         xfrm_dst_destroy(xdst);
 220 }
 221
 222 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 223                              int unregister)
 224 {
 225         struct xfrm_dst *xdst;
 226
 227         if (!unregister)
 228                 return;
 229
 230         xdst = (struct xfrm_dst *)dst;
 231         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 232                 struct inet6_dev *loopback_idev =
 233                         in6_dev_get(dev_net(dev)->loopback_dev);
 234                 BUG_ON(!loopback_idev);
 235
 236                 do {
 237                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 238                         xdst->u.rt6.rt6i_idev = loopback_idev;
 239                         in6_dev_hold(loopback_idev);
 240                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 241                 } while (xdst->u.dst.xfrm);
 242
 243                 __in6_dev_put(loopback_idev);
 244         }
 245
 246         xfrm_dst_ifdown(dst, dev);
 247 }
 248
 249 static struct dst_ops xfrm6_dst_ops = {
 250         .family =               AF_INET6,
 251         .protocol =             cpu_to_be16(ETH_P_IPV6),
 252         .gc =                   xfrm6_garbage_collect,
 253         .update_pmtu =          xfrm6_update_pmtu,
 254         .destroy =              xfrm6_dst_destroy,
 255         .ifdown =               xfrm6_dst_ifdown,
 256         .local_out =            __ip6_local_out,
 257         .gc_thresh =            1024,
 258         .entries =              ATOMIC_INIT(0),
 259 };
 260
 261 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 262         .family =               AF_INET6,
 263         .dst_ops =              &xfrm6_dst_ops,
 264         .dst_lookup =           xfrm6_dst_lookup,
 265         .get_saddr =            xfrm6_get_saddr,
 266         .decode_session =       _decode_session6,
 267         .get_tos =              xfrm6_get_tos,
 268         .init_path =            xfrm6_init_path,
 269         .fill_dst =             xfrm6_fill_dst,
 270 };
 271
 272 static int __init xfrm6_policy_init(void)
 273 {
 274         return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 275 }
 276
 277 static void xfrm6_policy_fini(void)
 278 {
 279         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 280 }
 281
 282 #ifdef CONFIG_SYSCTL
 283 static struct ctl_table xfrm6_policy_table[] = {
 284         {
 285                 .procname       = "xfrm6_gc_thresh",
 286                 .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
 287                 .maxlen         = sizeof(int),
 288                 .mode           = 0644,
 289                 .proc_handler   = proc_dointvec,
 290         },
 291         { }
 292 };
 293
 294 static struct ctl_table_header *sysctl_hdr;
 295 #endif
 296
 297 int __init xfrm6_init(void)
 298 {
 299         int ret;
 300         unsigned int gc_thresh;
 301
 302         /*
 303          * We need a good default value for the xfrm6 gc threshold.
 304          * In ipv4 we set it to the route hash table size * 8, which
 305          * is half the size of the maximaum route cache for ipv4.  It
 306          * would be good to do the same thing for v6, except the table is
 307          * constructed differently here.  Here each table for a net namespace
 308          * can have FIB_TABLE_HASHSZ entries, so lets go with the same
 309          * computation that we used for ipv4 here.  Also, lets keep the initial
 310          * gc_thresh to a minimum of 1024, since, the ipv6 route cache defaults
 311          * to that as a minimum as well
 312          */
 313         gc_thresh = FIB6_TABLE_HASHSZ * 8;
 314         xfrm6_dst_ops.gc_thresh = (gc_thresh < 1024) ? 1024 : gc_thresh;
 315
 316         ret = xfrm6_policy_init();
 317         if (ret)
 318                 goto out;
 319
 320         ret = xfrm6_state_init();
 321         if (ret)
 322                 goto out_policy;
 323
 324 #ifdef CONFIG_SYSCTL
 325         sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv6_ctl_path,
 326                                                 xfrm6_policy_table);
 327 #endif
 328 out:
 329         return ret;
 330 out_policy:
 331         xfrm6_policy_fini();
 332         goto out;
 333 }
 334
 335 void xfrm6_fini(void)
 336 {
 337 #ifdef CONFIG_SYSCTL
 338         if (sysctl_hdr)
 339                 unregister_net_sysctl_table(sysctl_hdr);
 340 #endif
 341         //xfrm6_input_fini();
 342         xfrm6_policy_fini();
 343         xfrm6_state_fini();
 344 }