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 dst_ops xfrm6_dst_ops;
  28static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
  29
  30static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos,
  31                                          xfrm_address_t *saddr,
  32                                          xfrm_address_t *daddr)
  33{
  34        struct flowi fl = {};
  35        struct dst_entry *dst;
  36        int err;
  37
  38        memcpy(&fl.fl6_dst, daddr, sizeof(fl.fl6_dst));
  39        if (saddr)
  40                memcpy(&fl.fl6_src, saddr, sizeof(fl.fl6_src));
  41
  42        dst = ip6_route_output(net, NULL, &fl);
  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 struct dst_entry *
  72__xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
  73{
  74        struct dst_entry *dst;
  75
  76        /* Still not clear if we should set fl->fl6_{src,dst}... */
  77        read_lock_bh(&policy->lock);
  78        for (dst = policy->bundles; dst; dst = dst->next) {
  79                struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
  80                struct in6_addr fl_dst_prefix, fl_src_prefix;
  81
  82                ipv6_addr_prefix(&fl_dst_prefix,
  83                                 &fl->fl6_dst,
  84                                 xdst->u.rt6.rt6i_dst.plen);
  85                ipv6_addr_prefix(&fl_src_prefix,
  86                                 &fl->fl6_src,
  87                                 xdst->u.rt6.rt6i_src.plen);
  88                if (ipv6_addr_equal(&xdst->u.rt6.rt6i_dst.addr, &fl_dst_prefix) &&
  89                    ipv6_addr_equal(&xdst->u.rt6.rt6i_src.addr, &fl_src_prefix) &&
  90                    xfrm_bundle_ok(policy, xdst, fl, AF_INET6,
  91                                   (xdst->u.rt6.rt6i_dst.plen != 128 ||
  92                                    xdst->u.rt6.rt6i_src.plen != 128))) {
  93                        dst_clone(dst);
  94                        break;
  95                }
  96        }
  97        read_unlock_bh(&policy->lock);
  98        return dst;
  99}
 100
 101static int xfrm6_get_tos(struct flowi *fl)
 102{
 103        return 0;
 104}
 105
 106static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
 107                           int nfheader_len)
 108{
 109        if (dst->ops->family == AF_INET6) {
 110                struct rt6_info *rt = (struct rt6_info*)dst;
 111                if (rt->rt6i_node)
 112                        path->path_cookie = rt->rt6i_node->fn_sernum;
 113        }
 114
 115        path->u.rt6.rt6i_nfheader_len = nfheader_len;
 116
 117        return 0;
 118}
 119
 120static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev)
 121{
 122        struct rt6_info *rt = (struct rt6_info*)xdst->route;
 123
 124        xdst->u.dst.dev = dev;
 125        dev_hold(dev);
 126
 127        xdst->u.rt6.rt6i_idev = in6_dev_get(rt->u.dst.dev);
 128        if (!xdst->u.rt6.rt6i_idev)
 129                return -ENODEV;
 130
 131        /* Sheit... I remember I did this right. Apparently,
 132         * it was magically lost, so this code needs audit */
 133        xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
 134                                                   RTF_LOCAL);
 135        xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
 136        xdst->u.rt6.rt6i_node = rt->rt6i_node;
 137        if (rt->rt6i_node)
 138                xdst->route_cookie = rt->rt6i_node->fn_sernum;
 139        xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
 140        xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
 141        xdst->u.rt6.rt6i_src = rt->rt6i_src;
 142
 143        return 0;
 144}
 145
 146static inline void
 147_decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
 148{
 149        int onlyproto = 0;
 150        u16 offset = skb_network_header_len(skb);
 151        struct ipv6hdr *hdr = ipv6_hdr(skb);
 152        struct ipv6_opt_hdr *exthdr;
 153        const unsigned char *nh = skb_network_header(skb);
 154        u8 nexthdr = nh[IP6CB(skb)->nhoff];
 155
 156        memset(fl, 0, sizeof(struct flowi));
 157        ipv6_addr_copy(&fl->fl6_dst, reverse ? &hdr->saddr : &hdr->daddr);
 158        ipv6_addr_copy(&fl->fl6_src, reverse ? &hdr->daddr : &hdr->saddr);
 159
 160        while (pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
 161                nh = skb_network_header(skb);
 162                exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 163
 164                switch (nexthdr) {
 165                case NEXTHDR_FRAGMENT:
 166                        onlyproto = 1;
 167                case NEXTHDR_ROUTING:
 168                case NEXTHDR_HOP:
 169                case NEXTHDR_DEST:
 170                        offset += ipv6_optlen(exthdr);
 171                        nexthdr = exthdr->nexthdr;
 172                        exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 173                        break;
 174
 175                case IPPROTO_UDP:
 176                case IPPROTO_UDPLITE:
 177                case IPPROTO_TCP:
 178                case IPPROTO_SCTP:
 179                case IPPROTO_DCCP:
 180                        if (!onlyproto && pskb_may_pull(skb, nh + offset + 4 - skb->data)) {
 181                                __be16 *ports = (__be16 *)exthdr;
 182
 183                                fl->fl_ip_sport = ports[!!reverse];
 184                                fl->fl_ip_dport = ports[!reverse];
 185                        }
 186                        fl->proto = nexthdr;
 187                        return;
 188
 189                case IPPROTO_ICMPV6:
 190                        if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
 191                                u8 *icmp = (u8 *)exthdr;
 192
 193                                fl->fl_icmp_type = icmp[0];
 194                                fl->fl_icmp_code = icmp[1];
 195                        }
 196                        fl->proto = nexthdr;
 197                        return;
 198
 199#if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 200                case IPPROTO_MH:
 201                        if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
 202                                struct ip6_mh *mh;
 203                                mh = (struct ip6_mh *)exthdr;
 204
 205                                fl->fl_mh_type = mh->ip6mh_type;
 206                        }
 207                        fl->proto = nexthdr;
 208                        return;
 209#endif
 210
 211                /* XXX Why are there these headers? */
 212                case IPPROTO_AH:
 213                case IPPROTO_ESP:
 214                case IPPROTO_COMP:
 215                default:
 216                        fl->fl_ipsec_spi = 0;
 217                        fl->proto = nexthdr;
 218                        return;
 219                }
 220        }
 221}
 222
 223static inline int xfrm6_garbage_collect(struct dst_ops *ops)
 224{
 225        xfrm6_policy_afinfo.garbage_collect(&init_net);
 226        return (atomic_read(&xfrm6_dst_ops.entries) > xfrm6_dst_ops.gc_thresh*2);
 227}
 228
 229static void xfrm6_update_pmtu(struct dst_entry *dst, u32 mtu)
 230{
 231        struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 232        struct dst_entry *path = xdst->route;
 233
 234        path->ops->update_pmtu(path, mtu);
 235}
 236
 237static void xfrm6_dst_destroy(struct dst_entry *dst)
 238{
 239        struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 240
 241        if (likely(xdst->u.rt6.rt6i_idev))
 242                in6_dev_put(xdst->u.rt6.rt6i_idev);
 243        xfrm_dst_destroy(xdst);
 244}
 245
 246static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 247                             int unregister)
 248{
 249        struct xfrm_dst *xdst;
 250
 251        if (!unregister)
 252                return;
 253
 254        xdst = (struct xfrm_dst *)dst;
 255        if (xdst->u.rt6.rt6i_idev->dev == dev) {
 256                struct inet6_dev *loopback_idev =
 257                        in6_dev_get(dev_net(dev)->loopback_dev);
 258                BUG_ON(!loopback_idev);
 259
 260                do {
 261                        in6_dev_put(xdst->u.rt6.rt6i_idev);
 262                        xdst->u.rt6.rt6i_idev = loopback_idev;
 263                        in6_dev_hold(loopback_idev);
 264                        xdst = (struct xfrm_dst *)xdst->u.dst.child;
 265                } while (xdst->u.dst.xfrm);
 266
 267                __in6_dev_put(loopback_idev);
 268        }
 269
 270        xfrm_dst_ifdown(dst, dev);
 271}
 272
 273static struct dst_ops xfrm6_dst_ops = {
 274        .family =               AF_INET6,
 275        .protocol =             __constant_htons(ETH_P_IPV6),
 276        .gc =                   xfrm6_garbage_collect,
 277        .update_pmtu =          xfrm6_update_pmtu,
 278        .destroy =              xfrm6_dst_destroy,
 279        .ifdown =               xfrm6_dst_ifdown,
 280        .local_out =            __ip6_local_out,
 281        .gc_thresh =            1024,
 282        .entries =              ATOMIC_INIT(0),
 283};
 284
 285static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 286        .family =               AF_INET6,
 287        .dst_ops =              &xfrm6_dst_ops,
 288        .dst_lookup =           xfrm6_dst_lookup,
 289        .get_saddr =            xfrm6_get_saddr,
 290        .find_bundle =          __xfrm6_find_bundle,
 291        .decode_session =       _decode_session6,
 292        .get_tos =              xfrm6_get_tos,
 293        .init_path =            xfrm6_init_path,
 294        .fill_dst =             xfrm6_fill_dst,
 295};
 296
 297static int __init xfrm6_policy_init(void)
 298{
 299        return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 300}
 301
 302static void xfrm6_policy_fini(void)
 303{
 304        xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 305}
 306
 307int __init xfrm6_init(void)
 308{
 309        int ret;
 310
 311        ret = xfrm6_policy_init();
 312        if (ret)
 313                goto out;
 314
 315        ret = xfrm6_state_init();
 316        if (ret)
 317                goto out_policy;
 318out:
 319        return ret;
 320out_policy:
 321        xfrm6_policy_fini();
 322        goto out;
 323}
 324
 325void xfrm6_fini(void)
 326{
 327        //xfrm6_input_fini();
 328        xfrm6_policy_fini();
 329        xfrm6_state_fini();
 330}
 331