linux/net/ipv6/xfrm6_policy.c
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   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
  27static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
  28
  29static 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
  53static 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
  71static int xfrm6_get_tos(const struct flowi *fl)
  72{
  73        return 0;
  74}
  75
  76static void xfrm6_init_dst(struct net *net, struct xfrm_dst *xdst)
  77{
  78        struct rt6_info *rt = (struct rt6_info *)xdst;
  79
  80        rt6_init_peer(rt, net->ipv6.peers);
  81}
  82
  83static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
  84                           int nfheader_len)
  85{
  86        if (dst->ops->family == AF_INET6) {
  87                struct rt6_info *rt = (struct rt6_info*)dst;
  88                if (rt->rt6i_node)
  89                        path->path_cookie = rt->rt6i_node->fn_sernum;
  90        }
  91
  92        path->u.rt6.rt6i_nfheader_len = nfheader_len;
  93
  94        return 0;
  95}
  96
  97static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
  98                          const struct flowi *fl)
  99{
 100        struct rt6_info *rt = (struct rt6_info*)xdst->route;
 101
 102        xdst->u.dst.dev = dev;
 103        dev_hold(dev);
 104
 105        xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
 106        if (!xdst->u.rt6.rt6i_idev)
 107                return -ENODEV;
 108
 109        rt6_transfer_peer(&xdst->u.rt6, rt);
 110
 111        /* Sheit... I remember I did this right. Apparently,
 112         * it was magically lost, so this code needs audit */
 113        xdst->u.rt6.n = neigh_clone(rt->n);
 114        xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
 115                                                   RTF_LOCAL);
 116        xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
 117        xdst->u.rt6.rt6i_node = rt->rt6i_node;
 118        if (rt->rt6i_node)
 119                xdst->route_cookie = rt->rt6i_node->fn_sernum;
 120        xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
 121        xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
 122        xdst->u.rt6.rt6i_src = rt->rt6i_src;
 123
 124        return 0;
 125}
 126
 127static inline void
 128_decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
 129{
 130        struct flowi6 *fl6 = &fl->u.ip6;
 131        int onlyproto = 0;
 132        u16 offset = skb_network_header_len(skb);
 133        const struct ipv6hdr *hdr = ipv6_hdr(skb);
 134        struct ipv6_opt_hdr *exthdr;
 135        const unsigned char *nh = skb_network_header(skb);
 136        u8 nexthdr = nh[IP6CB(skb)->nhoff];
 137
 138        memset(fl6, 0, sizeof(struct flowi6));
 139        fl6->flowi6_mark = skb->mark;
 140
 141        fl6->daddr = reverse ? hdr->saddr : hdr->daddr;
 142        fl6->saddr = reverse ? hdr->daddr : hdr->saddr;
 143
 144        while (nh + offset + 1 < skb->data ||
 145               pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
 146                nh = skb_network_header(skb);
 147                exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 148
 149                switch (nexthdr) {
 150                case NEXTHDR_FRAGMENT:
 151                        onlyproto = 1;
 152                case NEXTHDR_ROUTING:
 153                case NEXTHDR_HOP:
 154                case NEXTHDR_DEST:
 155                        offset += ipv6_optlen(exthdr);
 156                        nexthdr = exthdr->nexthdr;
 157                        exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 158                        break;
 159
 160                case IPPROTO_UDP:
 161                case IPPROTO_UDPLITE:
 162                case IPPROTO_TCP:
 163                case IPPROTO_SCTP:
 164                case IPPROTO_DCCP:
 165                        if (!onlyproto && (nh + offset + 4 < skb->data ||
 166                             pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
 167                                __be16 *ports = (__be16 *)exthdr;
 168
 169                                fl6->fl6_sport = ports[!!reverse];
 170                                fl6->fl6_dport = ports[!reverse];
 171                        }
 172                        fl6->flowi6_proto = nexthdr;
 173                        return;
 174
 175                case IPPROTO_ICMPV6:
 176                        if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
 177                                u8 *icmp = (u8 *)exthdr;
 178
 179                                fl6->fl6_icmp_type = icmp[0];
 180                                fl6->fl6_icmp_code = icmp[1];
 181                        }
 182                        fl6->flowi6_proto = nexthdr;
 183                        return;
 184
 185#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 186                case IPPROTO_MH:
 187                        if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
 188                                struct ip6_mh *mh;
 189                                mh = (struct ip6_mh *)exthdr;
 190
 191                                fl6->fl6_mh_type = mh->ip6mh_type;
 192                        }
 193                        fl6->flowi6_proto = nexthdr;
 194                        return;
 195#endif
 196
 197                /* XXX Why are there these headers? */
 198                case IPPROTO_AH:
 199                case IPPROTO_ESP:
 200                case IPPROTO_COMP:
 201                default:
 202                        fl6->fl6_ipsec_spi = 0;
 203                        fl6->flowi6_proto = nexthdr;
 204                        return;
 205                }
 206        }
 207}
 208
 209static inline int xfrm6_garbage_collect(struct dst_ops *ops)
 210{
 211        struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
 212
 213        xfrm6_policy_afinfo.garbage_collect(net);
 214        return dst_entries_get_fast(ops) > ops->gc_thresh * 2;
 215}
 216
 217static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk,
 218                              struct sk_buff *skb, u32 mtu)
 219{
 220        struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 221        struct dst_entry *path = xdst->route;
 222
 223        path->ops->update_pmtu(path, sk, skb, mtu);
 224}
 225
 226static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk,
 227                           struct sk_buff *skb)
 228{
 229        struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 230        struct dst_entry *path = xdst->route;
 231
 232        path->ops->redirect(path, sk, skb);
 233}
 234
 235static void xfrm6_dst_destroy(struct dst_entry *dst)
 236{
 237        struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 238
 239        if (likely(xdst->u.rt6.rt6i_idev))
 240                in6_dev_put(xdst->u.rt6.rt6i_idev);
 241        dst_destroy_metrics_generic(dst);
 242        if (rt6_has_peer(&xdst->u.rt6)) {
 243                struct inet_peer *peer = rt6_peer_ptr(&xdst->u.rt6);
 244                inet_putpeer(peer);
 245        }
 246        xfrm_dst_destroy(xdst);
 247}
 248
 249static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 250                             int unregister)
 251{
 252        struct xfrm_dst *xdst;
 253
 254        if (!unregister)
 255                return;
 256
 257        xdst = (struct xfrm_dst *)dst;
 258        if (xdst->u.rt6.rt6i_idev->dev == dev) {
 259                struct inet6_dev *loopback_idev =
 260                        in6_dev_get(dev_net(dev)->loopback_dev);
 261                BUG_ON(!loopback_idev);
 262
 263                do {
 264                        in6_dev_put(xdst->u.rt6.rt6i_idev);
 265                        xdst->u.rt6.rt6i_idev = loopback_idev;
 266                        in6_dev_hold(loopback_idev);
 267                        xdst = (struct xfrm_dst *)xdst->u.dst.child;
 268                } while (xdst->u.dst.xfrm);
 269
 270                __in6_dev_put(loopback_idev);
 271        }
 272
 273        xfrm_dst_ifdown(dst, dev);
 274}
 275
 276static struct dst_ops xfrm6_dst_ops = {
 277        .family =               AF_INET6,
 278        .protocol =             cpu_to_be16(ETH_P_IPV6),
 279        .gc =                   xfrm6_garbage_collect,
 280        .update_pmtu =          xfrm6_update_pmtu,
 281        .redirect =             xfrm6_redirect,
 282        .cow_metrics =          dst_cow_metrics_generic,
 283        .destroy =              xfrm6_dst_destroy,
 284        .ifdown =               xfrm6_dst_ifdown,
 285        .local_out =            __ip6_local_out,
 286        .gc_thresh =            1024,
 287};
 288
 289static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 290        .family =               AF_INET6,
 291        .dst_ops =              &xfrm6_dst_ops,
 292        .dst_lookup =           xfrm6_dst_lookup,
 293        .get_saddr =            xfrm6_get_saddr,
 294        .decode_session =       _decode_session6,
 295        .get_tos =              xfrm6_get_tos,
 296        .init_dst =             xfrm6_init_dst,
 297        .init_path =            xfrm6_init_path,
 298        .fill_dst =             xfrm6_fill_dst,
 299        .blackhole_route =      ip6_blackhole_route,
 300};
 301
 302static int __init xfrm6_policy_init(void)
 303{
 304        return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 305}
 306
 307static void xfrm6_policy_fini(void)
 308{
 309        xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 310}
 311
 312#ifdef CONFIG_SYSCTL
 313static struct ctl_table xfrm6_policy_table[] = {
 314        {
 315                .procname       = "xfrm6_gc_thresh",
 316                .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
 317                .maxlen         = sizeof(int),
 318                .mode           = 0644,
 319                .proc_handler   = proc_dointvec,
 320        },
 321        { }
 322};
 323
 324static struct ctl_table_header *sysctl_hdr;
 325#endif
 326
 327int __init xfrm6_init(void)
 328{
 329        int ret;
 330        unsigned int gc_thresh;
 331
 332        /*
 333         * We need a good default value for the xfrm6 gc threshold.
 334         * In ipv4 we set it to the route hash table size * 8, which
 335         * is half the size of the maximaum route cache for ipv4.  It
 336         * would be good to do the same thing for v6, except the table is
 337         * constructed differently here.  Here each table for a net namespace
 338         * can have FIB_TABLE_HASHSZ entries, so lets go with the same
 339         * computation that we used for ipv4 here.  Also, lets keep the initial
 340         * gc_thresh to a minimum of 1024, since, the ipv6 route cache defaults
 341         * to that as a minimum as well
 342         */
 343        gc_thresh = FIB6_TABLE_HASHSZ * 8;
 344        xfrm6_dst_ops.gc_thresh = (gc_thresh < 1024) ? 1024 : gc_thresh;
 345        dst_entries_init(&xfrm6_dst_ops);
 346
 347        ret = xfrm6_policy_init();
 348        if (ret) {
 349                dst_entries_destroy(&xfrm6_dst_ops);
 350                goto out;
 351        }
 352        ret = xfrm6_state_init();
 353        if (ret)
 354                goto out_policy;
 355
 356#ifdef CONFIG_SYSCTL
 357        sysctl_hdr = register_net_sysctl(&init_net, "net/ipv6",
 358                                         xfrm6_policy_table);
 359#endif
 360out:
 361        return ret;
 362out_policy:
 363        xfrm6_policy_fini();
 364        goto out;
 365}
 366
 367void xfrm6_fini(void)
 368{
 369#ifdef CONFIG_SYSCTL
 370        if (sysctl_hdr)
 371                unregister_net_sysctl_table(sysctl_hdr);
 372#endif
 373        //xfrm6_input_fini();
 374        xfrm6_policy_fini();
 375        xfrm6_state_fini();
 376        dst_entries_destroy(&xfrm6_dst_ops);
 377}
 378
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