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 IS_ENABLED(CONFIG_IPV6_MIP6)
  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                                           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
  53 static 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, &daddr->in6, 0, &saddr->in6);
  65         dst_release(dst);
  66         return 0;
  67 }
  68
  69 static int xfrm6_get_tos(const struct flowi *fl)
  70 {
  71         return 0;
  72 }
  73
  74 static void xfrm6_init_dst(struct net *net, struct xfrm_dst *xdst)
  75 {
  76         struct rt6_info *rt = (struct rt6_info *)xdst;
  77
  78         rt6_init_peer(rt, net->ipv6.peers);
  79 }
  80
  81 static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
  82                            int nfheader_len)
  83 {
  84         if (dst->ops->family == AF_INET6) {
  85                 struct rt6_info *rt = (struct rt6_info *)dst;
  86                 if (rt->rt6i_node)
  87                         path->path_cookie = rt->rt6i_node->fn_sernum;
  88         }
  89
  90         path->u.rt6.rt6i_nfheader_len = nfheader_len;
  91
  92         return 0;
  93 }
  94
  95 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
  96                           const struct flowi *fl)
  97 {
  98         struct rt6_info *rt = (struct rt6_info *)xdst->route;
  99
 100         xdst->u.dst.dev = dev;
 101         dev_hold(dev);
 102
 103         xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
 104         if (!xdst->u.rt6.rt6i_idev) {
 105                 dev_put(dev);
 106                 return -ENODEV;
 107         }
 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.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
 114                                                    RTF_LOCAL);
 115         xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
 116         xdst->u.rt6.rt6i_node = rt->rt6i_node;
 117         if (rt->rt6i_node)
 118                 xdst->route_cookie = rt->rt6i_node->fn_sernum;
 119         xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
 120         xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
 121         xdst->u.rt6.rt6i_src = rt->rt6i_src;
 122
 123         return 0;
 124 }
 125
 126 static inline void
 127 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
 128 {
 129         struct flowi6 *fl6 = &fl->u.ip6;
 130         int onlyproto = 0;
 131         const struct ipv6hdr *hdr = ipv6_hdr(skb);
 132         u16 offset = sizeof(*hdr);
 133         struct ipv6_opt_hdr *exthdr;
 134         const unsigned char *nh = skb_network_header(skb);
 135         u16 nhoff = IP6CB(skb)->nhoff;
 136         int oif = 0;
 137         u8 nexthdr;
 138
 139         if (!nhoff)
 140                 nhoff = offsetof(struct ipv6hdr, nexthdr);
 141
 142         nexthdr = nh[nhoff];
 143
 144         if (skb_dst(skb))
 145                 oif = skb_dst(skb)->dev->ifindex;
 146
 147         memset(fl6, 0, sizeof(struct flowi6));
 148         fl6->flowi6_mark = skb->mark;
 149         fl6->flowi6_oif = reverse ? skb->skb_iif : oif;
 150
 151         fl6->daddr = reverse ? hdr->saddr : hdr->daddr;
 152         fl6->saddr = reverse ? hdr->daddr : hdr->saddr;
 153
 154         while (nh + offset + 1 < skb->data ||
 155                pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
 156                 nh = skb_network_header(skb);
 157                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 158
 159                 switch (nexthdr) {
 160                 case NEXTHDR_FRAGMENT:
 161                         onlyproto = 1;
 162                 case NEXTHDR_ROUTING:
 163                 case NEXTHDR_HOP:
 164                 case NEXTHDR_DEST:
 165                         offset += ipv6_optlen(exthdr);
 166                         nexthdr = exthdr->nexthdr;
 167                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 168                         break;
 169
 170                 case IPPROTO_UDP:
 171                 case IPPROTO_UDPLITE:
 172                 case IPPROTO_TCP:
 173                 case IPPROTO_SCTP:
 174                 case IPPROTO_DCCP:
 175                         if (!onlyproto && (nh + offset + 4 < skb->data ||
 176                              pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
 177                                 __be16 *ports;
 178
 179                                 nh = skb_network_header(skb);
 180                                 ports = (__be16 *)(nh + offset);
 181                                 fl6->fl6_sport = ports[!!reverse];
 182                                 fl6->fl6_dport = ports[!reverse];
 183                         }
 184                         fl6->flowi6_proto = nexthdr;
 185                         return;
 186
 187                 case IPPROTO_ICMPV6:
 188                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 2 - skb->data)) {
 189                                 u8 *icmp;
 190
 191                                 nh = skb_network_header(skb);
 192                                 icmp = (u8 *)(nh + offset);
 193                                 fl6->fl6_icmp_type = icmp[0];
 194                                 fl6->fl6_icmp_code = icmp[1];
 195                         }
 196                         fl6->flowi6_proto = nexthdr;
 197                         return;
 198
 199 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 200                 case IPPROTO_MH:
 201                         offset += ipv6_optlen(exthdr);
 202                         if (!onlyproto && pskb_may_pull(skb, nh + offset + 3 - skb->data)) {
 203                                 struct ip6_mh *mh;
 204
 205                                 nh = skb_network_header(skb);
 206                                 mh = (struct ip6_mh *)(nh + offset);
 207                                 fl6->fl6_mh_type = mh->ip6mh_type;
 208                         }
 209                         fl6->flowi6_proto = nexthdr;
 210                         return;
 211 #endif
 212
 213                 /* XXX Why are there these headers? */
 214                 case IPPROTO_AH:
 215                 case IPPROTO_ESP:
 216                 case IPPROTO_COMP:
 217                 default:
 218                         fl6->fl6_ipsec_spi = 0;
 219                         fl6->flowi6_proto = nexthdr;
 220                         return;
 221                 }
 222         }
 223 }
 224
 225 static inline int xfrm6_garbage_collect(struct dst_ops *ops)
 226 {
 227         struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
 228
 229         xfrm6_policy_afinfo.garbage_collect(net);
 230         return dst_entries_get_fast(ops) > ops->gc_thresh * 2;
 231 }
 232
 233 static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk,
 234                               struct sk_buff *skb, u32 mtu)
 235 {
 236         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 237         struct dst_entry *path = xdst->route;
 238
 239         path->ops->update_pmtu(path, sk, skb, mtu);
 240 }
 241
 242 static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk,
 243                            struct sk_buff *skb)
 244 {
 245         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 246         struct dst_entry *path = xdst->route;
 247
 248         path->ops->redirect(path, sk, skb);
 249 }
 250
 251 static void xfrm6_dst_destroy(struct dst_entry *dst)
 252 {
 253         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 254
 255         if (likely(xdst->u.rt6.rt6i_idev))
 256                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 257         dst_destroy_metrics_generic(dst);
 258         if (rt6_has_peer(&xdst->u.rt6)) {
 259                 struct inet_peer *peer = rt6_peer_ptr(&xdst->u.rt6);
 260                 inet_putpeer(peer);
 261         }
 262         xfrm_dst_destroy(xdst);
 263 }
 264
 265 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 266                              int unregister)
 267 {
 268         struct xfrm_dst *xdst;
 269
 270         if (!unregister)
 271                 return;
 272
 273         xdst = (struct xfrm_dst *)dst;
 274         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 275                 struct inet6_dev *loopback_idev =
 276                         in6_dev_get(dev_net(dev)->loopback_dev);
 277                 BUG_ON(!loopback_idev);
 278
 279                 do {
 280                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 281                         xdst->u.rt6.rt6i_idev = loopback_idev;
 282                         in6_dev_hold(loopback_idev);
 283                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 284                 } while (xdst->u.dst.xfrm);
 285
 286                 __in6_dev_put(loopback_idev);
 287         }
 288
 289         xfrm_dst_ifdown(dst, dev);
 290 }
 291
 292 static struct dst_ops xfrm6_dst_ops = {
 293         .family =               AF_INET6,
 294         .gc =                   xfrm6_garbage_collect,
 295         .update_pmtu =          xfrm6_update_pmtu,
 296         .redirect =             xfrm6_redirect,
 297         .cow_metrics =          dst_cow_metrics_generic,
 298         .destroy =              xfrm6_dst_destroy,
 299         .ifdown =               xfrm6_dst_ifdown,
 300         .local_out =            __ip6_local_out,
 301         .gc_thresh =            32768,
 302 };
 303
 304 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 305         .family =               AF_INET6,
 306         .dst_ops =              &xfrm6_dst_ops,
 307         .dst_lookup =           xfrm6_dst_lookup,
 308         .get_saddr =            xfrm6_get_saddr,
 309         .decode_session =       _decode_session6,
 310         .get_tos =              xfrm6_get_tos,
 311         .init_dst =             xfrm6_init_dst,
 312         .init_path =            xfrm6_init_path,
 313         .fill_dst =             xfrm6_fill_dst,
 314         .blackhole_route =      ip6_blackhole_route,
 315 };
 316
 317 static int __init xfrm6_policy_init(void)
 318 {
 319         return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 320 }
 321
 322 static void xfrm6_policy_fini(void)
 323 {
 324         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 325 }
 326
 327 #ifdef CONFIG_SYSCTL
 328 static struct ctl_table xfrm6_policy_table[] = {
 329         {
 330                 .procname       = "xfrm6_gc_thresh",
 331                 .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
 332                 .maxlen         = sizeof(int),
 333                 .mode           = 0644,
 334                 .proc_handler   = proc_dointvec,
 335         },
 336         { }
 337 };
 338
 339 static int __net_init xfrm6_net_init(struct net *net)
 340 {
 341         struct ctl_table *table;
 342         struct ctl_table_header *hdr;
 343
 344         table = xfrm6_policy_table;
 345         if (!net_eq(net, &init_net)) {
 346                 table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL);
 347                 if (!table)
 348                         goto err_alloc;
 349
 350                 table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh;
 351         }
 352
 353         hdr = register_net_sysctl(net, "net/ipv6", table);
 354         if (!hdr)
 355                 goto err_reg;
 356
 357         net->ipv6.sysctl.xfrm6_hdr = hdr;
 358         return 0;
 359
 360 err_reg:
 361         if (!net_eq(net, &init_net))
 362                 kfree(table);
 363 err_alloc:
 364         return -ENOMEM;
 365 }
 366
 367 static void __net_exit xfrm6_net_exit(struct net *net)
 368 {
 369         struct ctl_table *table;
 370
 371         if (!net->ipv6.sysctl.xfrm6_hdr)
 372                 return;
 373
 374         table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg;
 375         unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr);
 376         if (!net_eq(net, &init_net))
 377                 kfree(table);
 378 }
 379
 380 static struct pernet_operations xfrm6_net_ops = {
 381         .init   = xfrm6_net_init,
 382         .exit   = xfrm6_net_exit,
 383 };
 384 #endif
 385
 386 int __init xfrm6_init(void)
 387 {
 388         int ret;
 389
 390         dst_entries_init(&xfrm6_dst_ops);
 391
 392         ret = xfrm6_policy_init();
 393         if (ret) {
 394                 dst_entries_destroy(&xfrm6_dst_ops);
 395                 goto out;
 396         }
 397         ret = xfrm6_state_init();
 398         if (ret)
 399                 goto out_policy;
 400
 401         ret = xfrm6_protocol_init();
 402         if (ret)
 403                 goto out_state;
 404
 405 #ifdef CONFIG_SYSCTL
 406         register_pernet_subsys(&xfrm6_net_ops);
 407 #endif
 408 out:
 409         return ret;
 410 out_state:
 411         xfrm6_state_fini();
 412 out_policy:
 413         xfrm6_policy_fini();
 414         goto out;
 415 }
 416
 417 void xfrm6_fini(void)
 418 {
 419 #ifdef CONFIG_SYSCTL
 420         unregister_pernet_subsys(&xfrm6_net_ops);
 421 #endif
 422         xfrm6_protocol_fini();
 423         xfrm6_policy_fini();
 424         xfrm6_state_fini();
 425         dst_entries_destroy(&xfrm6_dst_ops);
 426 }