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                                          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
  52static 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
  70static int xfrm6_get_tos(struct flowi *fl)
  71{
  72        return 0;
  73}
  74
  75static 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
  89static 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
 116static 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
 197static 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 dst_entries_get_fast(ops) > ops->gc_thresh * 2;
 203}
 204
 205static 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
 213static 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
 222static 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
 249static 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};
 259
 260static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 261        .family =               AF_INET6,
 262        .dst_ops =              &xfrm6_dst_ops,
 263        .dst_lookup =           xfrm6_dst_lookup,
 264        .get_saddr =            xfrm6_get_saddr,
 265        .decode_session =       _decode_session6,
 266        .get_tos =              xfrm6_get_tos,
 267        .init_path =            xfrm6_init_path,
 268        .fill_dst =             xfrm6_fill_dst,
 269};
 270
 271static int __init xfrm6_policy_init(void)
 272{
 273        return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 274}
 275
 276static void xfrm6_policy_fini(void)
 277{
 278        xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 279}
 280
 281#ifdef CONFIG_SYSCTL
 282static struct ctl_table xfrm6_policy_table[] = {
 283        {
 284                .procname       = "xfrm6_gc_thresh",
 285                .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
 286                .maxlen         = sizeof(int),
 287                .mode           = 0644,
 288                .proc_handler   = proc_dointvec,
 289        },
 290        { }
 291};
 292
 293static struct ctl_table_header *sysctl_hdr;
 294#endif
 295
 296int __init xfrm6_init(void)
 297{
 298        int ret;
 299        unsigned int gc_thresh;
 300
 301        /*
 302         * We need a good default value for the xfrm6 gc threshold.
 303         * In ipv4 we set it to the route hash table size * 8, which
 304         * is half the size of the maximaum route cache for ipv4.  It
 305         * would be good to do the same thing for v6, except the table is
 306         * constructed differently here.  Here each table for a net namespace
 307         * can have FIB_TABLE_HASHSZ entries, so lets go with the same
 308         * computation that we used for ipv4 here.  Also, lets keep the initial
 309         * gc_thresh to a minimum of 1024, since, the ipv6 route cache defaults
 310         * to that as a minimum as well
 311         */
 312        gc_thresh = FIB6_TABLE_HASHSZ * 8;
 313        xfrm6_dst_ops.gc_thresh = (gc_thresh < 1024) ? 1024 : gc_thresh;
 314        dst_entries_init(&xfrm6_dst_ops);
 315
 316        ret = xfrm6_policy_init();
 317        if (ret) {
 318                dst_entries_destroy(&xfrm6_dst_ops);
 319                goto out;
 320        }
 321        ret = xfrm6_state_init();
 322        if (ret)
 323                goto out_policy;
 324
 325#ifdef CONFIG_SYSCTL
 326        sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv6_ctl_path,
 327                                                xfrm6_policy_table);
 328#endif
 329out:
 330        return ret;
 331out_policy:
 332        xfrm6_policy_fini();
 333        goto out;
 334}
 335
 336void xfrm6_fini(void)
 337{
 338#ifdef CONFIG_SYSCTL
 339        if (sysctl_hdr)
 340                unregister_net_sysctl_table(sysctl_hdr);
 341#endif
 342        //xfrm6_input_fini();
 343        xfrm6_policy_fini();
 344        xfrm6_state_fini();
 345        dst_entries_destroy(&xfrm6_dst_ops);
 346}
 347