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 #include <net/l3mdev.h>
  24 #if IS_ENABLED(CONFIG_IPV6_MIP6)
  25 #include <net/mip6.h>
  26 #endif
  27
  28 static struct xfrm_policy_afinfo xfrm6_policy_afinfo;
  29
  30 static struct dst_entry *xfrm6_dst_lookup(struct net *net, int tos, int oif,
  31                                           const xfrm_address_t *saddr,
  32                                           const xfrm_address_t *daddr,
  33                                           u32 mark)
  34 {
  35         struct flowi6 fl6;
  36         struct dst_entry *dst;
  37         int err;
  38
  39         memset(&fl6, 0, sizeof(fl6));
  40         fl6.flowi6_oif = l3mdev_master_ifindex_by_index(net, oif);
  41         fl6.flowi6_flags = FLOWI_FLAG_SKIP_NH_OIF;
  42         fl6.flowi6_mark = mark;
  43         memcpy(&fl6.daddr, daddr, sizeof(fl6.daddr));
  44         if (saddr)
  45                 memcpy(&fl6.saddr, saddr, sizeof(fl6.saddr));
  46
  47         dst = ip6_route_output(net, NULL, &fl6);
  48
  49         err = dst->error;
  50         if (dst->error) {
  51                 dst_release(dst);
  52                 dst = ERR_PTR(err);
  53         }
  54
  55         return dst;
  56 }
  57
  58 static int xfrm6_get_saddr(struct net *net, int oif,
  59                            xfrm_address_t *saddr, xfrm_address_t *daddr,
  60                            u32 mark)
  61 {
  62         struct dst_entry *dst;
  63         struct net_device *dev;
  64
  65         dst = xfrm6_dst_lookup(net, 0, oif, NULL, daddr, mark);
  66         if (IS_ERR(dst))
  67                 return -EHOSTUNREACH;
  68
  69         dev = ip6_dst_idev(dst)->dev;
  70         ipv6_dev_get_saddr(dev_net(dev), dev, &daddr->in6, 0, &saddr->in6);
  71         dst_release(dst);
  72         return 0;
  73 }
  74
  75 static int xfrm6_get_tos(const struct flowi *fl)
  76 {
  77         return 0;
  78 }
  79
  80 static int xfrm6_init_path(struct xfrm_dst *path, struct dst_entry *dst,
  81                            int nfheader_len)
  82 {
  83         if (dst->ops->family == AF_INET6) {
  84                 struct rt6_info *rt = (struct rt6_info *)dst;
  85                 path->path_cookie = rt6_get_cookie(rt);
  86         }
  87
  88         path->u.rt6.rt6i_nfheader_len = nfheader_len;
  89
  90         return 0;
  91 }
  92
  93 static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev,
  94                           const struct flowi *fl)
  95 {
  96         struct rt6_info *rt = (struct rt6_info *)xdst->route;
  97
  98         xdst->u.dst.dev = dev;
  99         dev_hold(dev);
 100
 101         xdst->u.rt6.rt6i_idev = in6_dev_get(dev);
 102         if (!xdst->u.rt6.rt6i_idev) {
 103                 dev_put(dev);
 104                 return -ENODEV;
 105         }
 106
 107         /* Sheit... I remember I did this right. Apparently,
 108          * it was magically lost, so this code needs audit */
 109         xdst->u.rt6.rt6i_flags = rt->rt6i_flags & (RTF_ANYCAST |
 110                                                    RTF_LOCAL);
 111         xdst->u.rt6.rt6i_metric = rt->rt6i_metric;
 112         xdst->u.rt6.rt6i_node = rt->rt6i_node;
 113         xdst->route_cookie = rt6_get_cookie(rt);
 114         xdst->u.rt6.rt6i_gateway = rt->rt6i_gateway;
 115         xdst->u.rt6.rt6i_dst = rt->rt6i_dst;
 116         xdst->u.rt6.rt6i_src = rt->rt6i_src;
 117
 118         return 0;
 119 }
 120
 121 static inline void
 122 _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
 123 {
 124         struct flowi6 *fl6 = &fl->u.ip6;
 125         int onlyproto = 0;
 126         const struct ipv6hdr *hdr = ipv6_hdr(skb);
 127         u32 offset = sizeof(*hdr);
 128         struct ipv6_opt_hdr *exthdr;
 129         const unsigned char *nh = skb_network_header(skb);
 130         u16 nhoff = IP6CB(skb)->nhoff;
 131         int oif = 0;
 132         u8 nexthdr;
 133
 134         if (!nhoff)
 135                 nhoff = offsetof(struct ipv6hdr, nexthdr);
 136
 137         nexthdr = nh[nhoff];
 138
 139         if (skb_dst(skb))
 140                 oif = l3mdev_fib_oif(skb_dst(skb)->dev);
 141
 142         memset(fl6, 0, sizeof(struct flowi6));
 143         fl6->flowi6_mark = skb->mark;
 144         fl6->flowi6_oif = reverse ? skb->skb_iif : oif;
 145
 146         fl6->daddr = reverse ? hdr->saddr : hdr->daddr;
 147         fl6->saddr = reverse ? hdr->daddr : hdr->saddr;
 148
 149         while (nh + offset + 1 < skb->data ||
 150                pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
 151                 nh = skb_network_header(skb);
 152                 exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 153
 154                 switch (nexthdr) {
 155                 case NEXTHDR_FRAGMENT:
 156                         onlyproto = 1;
 157                 case NEXTHDR_ROUTING:
 158                 case NEXTHDR_HOP:
 159                 case NEXTHDR_DEST:
 160                         offset += ipv6_optlen(exthdr);
 161                         nexthdr = exthdr->nexthdr;
 162                         exthdr = (struct ipv6_opt_hdr *)(nh + offset);
 163                         break;
 164
 165                 case IPPROTO_UDP:
 166                 case IPPROTO_UDPLITE:
 167                 case IPPROTO_TCP:
 168                 case IPPROTO_SCTP:
 169                 case IPPROTO_DCCP:
 170                         if (!onlyproto && (nh + offset + 4 < skb->data ||
 171                              pskb_may_pull(skb, nh + offset + 4 - skb->data))) {
 172                                 __be16 *ports;
 173
 174                                 nh = skb_network_header(skb);
 175                                 ports = (__be16 *)(nh + offset);
 176                                 fl6->fl6_sport = ports[!!reverse];
 177                                 fl6->fl6_dport = ports[!reverse];
 178                         }
 179                         fl6->flowi6_proto = nexthdr;
 180                         return;
 181
 182                 case IPPROTO_ICMPV6:
 183                         if (!onlyproto && (nh + offset + 2 < skb->data ||
 184                             pskb_may_pull(skb, nh + offset + 2 - skb->data))) {
 185                                 u8 *icmp;
 186
 187                                 nh = skb_network_header(skb);
 188                                 icmp = (u8 *)(nh + offset);
 189                                 fl6->fl6_icmp_type = icmp[0];
 190                                 fl6->fl6_icmp_code = icmp[1];
 191                         }
 192                         fl6->flowi6_proto = nexthdr;
 193                         return;
 194
 195 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 196                 case IPPROTO_MH:
 197                         offset += ipv6_optlen(exthdr);
 198                         if (!onlyproto && (nh + offset + 3 < skb->data ||
 199                             pskb_may_pull(skb, nh + offset + 3 - skb->data))) {
 200                                 struct ip6_mh *mh;
 201
 202                                 nh = skb_network_header(skb);
 203                                 mh = (struct ip6_mh *)(nh + offset);
 204                                 fl6->fl6_mh_type = mh->ip6mh_type;
 205                         }
 206                         fl6->flowi6_proto = nexthdr;
 207                         return;
 208 #endif
 209
 210                 /* XXX Why are there these headers? */
 211                 case IPPROTO_AH:
 212                 case IPPROTO_ESP:
 213                 case IPPROTO_COMP:
 214                 default:
 215                         fl6->fl6_ipsec_spi = 0;
 216                         fl6->flowi6_proto = nexthdr;
 217                         return;
 218                 }
 219         }
 220 }
 221
 222 static inline int xfrm6_garbage_collect(struct dst_ops *ops)
 223 {
 224         struct net *net = container_of(ops, struct net, xfrm.xfrm6_dst_ops);
 225
 226         xfrm6_policy_afinfo.garbage_collect(net);
 227         return dst_entries_get_fast(ops) > ops->gc_thresh * 2;
 228 }
 229
 230 static void xfrm6_update_pmtu(struct dst_entry *dst, struct sock *sk,
 231                               struct sk_buff *skb, u32 mtu)
 232 {
 233         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 234         struct dst_entry *path = xdst->route;
 235
 236         path->ops->update_pmtu(path, sk, skb, mtu);
 237 }
 238
 239 static void xfrm6_redirect(struct dst_entry *dst, struct sock *sk,
 240                            struct sk_buff *skb)
 241 {
 242         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 243         struct dst_entry *path = xdst->route;
 244
 245         path->ops->redirect(path, sk, skb);
 246 }
 247
 248 static void xfrm6_dst_destroy(struct dst_entry *dst)
 249 {
 250         struct xfrm_dst *xdst = (struct xfrm_dst *)dst;
 251
 252         if (likely(xdst->u.rt6.rt6i_idev))
 253                 in6_dev_put(xdst->u.rt6.rt6i_idev);
 254         dst_destroy_metrics_generic(dst);
 255         xfrm_dst_destroy(xdst);
 256 }
 257
 258 static void xfrm6_dst_ifdown(struct dst_entry *dst, struct net_device *dev,
 259                              int unregister)
 260 {
 261         struct xfrm_dst *xdst;
 262
 263         if (!unregister)
 264                 return;
 265
 266         xdst = (struct xfrm_dst *)dst;
 267         if (xdst->u.rt6.rt6i_idev->dev == dev) {
 268                 struct inet6_dev *loopback_idev =
 269                         in6_dev_get(dev_net(dev)->loopback_dev);
 270                 BUG_ON(!loopback_idev);
 271
 272                 do {
 273                         in6_dev_put(xdst->u.rt6.rt6i_idev);
 274                         xdst->u.rt6.rt6i_idev = loopback_idev;
 275                         in6_dev_hold(loopback_idev);
 276                         xdst = (struct xfrm_dst *)xdst->u.dst.child;
 277                 } while (xdst->u.dst.xfrm);
 278
 279                 __in6_dev_put(loopback_idev);
 280         }
 281
 282         xfrm_dst_ifdown(dst, dev);
 283 }
 284
 285 static struct dst_ops xfrm6_dst_ops_template = {
 286         .family =               AF_INET6,
 287         .gc =                   xfrm6_garbage_collect,
 288         .update_pmtu =          xfrm6_update_pmtu,
 289         .redirect =             xfrm6_redirect,
 290         .cow_metrics =          dst_cow_metrics_generic,
 291         .destroy =              xfrm6_dst_destroy,
 292         .ifdown =               xfrm6_dst_ifdown,
 293         .local_out =            __ip6_local_out,
 294         .gc_thresh =            INT_MAX,
 295 };
 296
 297 static struct xfrm_policy_afinfo xfrm6_policy_afinfo = {
 298         .family =               AF_INET6,
 299         .dst_ops =              &xfrm6_dst_ops_template,
 300         .dst_lookup =           xfrm6_dst_lookup,
 301         .get_saddr =            xfrm6_get_saddr,
 302         .decode_session =       _decode_session6,
 303         .get_tos =              xfrm6_get_tos,
 304         .init_path =            xfrm6_init_path,
 305         .fill_dst =             xfrm6_fill_dst,
 306         .blackhole_route =      ip6_blackhole_route,
 307 };
 308
 309 static int __init xfrm6_policy_init(void)
 310 {
 311         return xfrm_policy_register_afinfo(&xfrm6_policy_afinfo);
 312 }
 313
 314 static void xfrm6_policy_fini(void)
 315 {
 316         xfrm_policy_unregister_afinfo(&xfrm6_policy_afinfo);
 317 }
 318
 319 #ifdef CONFIG_SYSCTL
 320 static struct ctl_table xfrm6_policy_table[] = {
 321         {
 322                 .procname       = "xfrm6_gc_thresh",
 323                 .data           = &init_net.xfrm.xfrm6_dst_ops.gc_thresh,
 324                 .maxlen         = sizeof(int),
 325                 .mode           = 0644,
 326                 .proc_handler   = proc_dointvec,
 327         },
 328         { }
 329 };
 330
 331 static int __net_init xfrm6_net_sysctl_init(struct net *net)
 332 {
 333         struct ctl_table *table;
 334         struct ctl_table_header *hdr;
 335
 336         table = xfrm6_policy_table;
 337         if (!net_eq(net, &init_net)) {
 338                 table = kmemdup(table, sizeof(xfrm6_policy_table), GFP_KERNEL);
 339                 if (!table)
 340                         goto err_alloc;
 341
 342                 table[0].data = &net->xfrm.xfrm6_dst_ops.gc_thresh;
 343         }
 344
 345         hdr = register_net_sysctl(net, "net/ipv6", table);
 346         if (!hdr)
 347                 goto err_reg;
 348
 349         net->ipv6.sysctl.xfrm6_hdr = hdr;
 350         return 0;
 351
 352 err_reg:
 353         if (!net_eq(net, &init_net))
 354                 kfree(table);
 355 err_alloc:
 356         return -ENOMEM;
 357 }
 358
 359 static void __net_exit xfrm6_net_sysctl_exit(struct net *net)
 360 {
 361         struct ctl_table *table;
 362
 363         if (!net->ipv6.sysctl.xfrm6_hdr)
 364                 return;
 365
 366         table = net->ipv6.sysctl.xfrm6_hdr->ctl_table_arg;
 367         unregister_net_sysctl_table(net->ipv6.sysctl.xfrm6_hdr);
 368         if (!net_eq(net, &init_net))
 369                 kfree(table);
 370 }
 371 #else /* CONFIG_SYSCTL */
 372 static int inline xfrm6_net_sysctl_init(struct net *net)
 373 {
 374         return 0;
 375 }
 376
 377 static void inline xfrm6_net_sysctl_exit(struct net *net)
 378 {
 379 }
 380 #endif
 381
 382 static int __net_init xfrm6_net_init(struct net *net)
 383 {
 384         int ret;
 385
 386         memcpy(&net->xfrm.xfrm6_dst_ops, &xfrm6_dst_ops_template,
 387                sizeof(xfrm6_dst_ops_template));
 388         ret = dst_entries_init(&net->xfrm.xfrm6_dst_ops);
 389         if (ret)
 390                 return ret;
 391
 392         ret = xfrm6_net_sysctl_init(net);
 393         if (ret)
 394                 dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
 395
 396         return ret;
 397 }
 398
 399 static void __net_exit xfrm6_net_exit(struct net *net)
 400 {
 401         xfrm6_net_sysctl_exit(net);
 402         dst_entries_destroy(&net->xfrm.xfrm6_dst_ops);
 403 }
 404
 405 static struct pernet_operations xfrm6_net_ops = {
 406         .init   = xfrm6_net_init,
 407         .exit   = xfrm6_net_exit,
 408 };
 409
 410 int __init xfrm6_init(void)
 411 {
 412         int ret;
 413
 414         ret = xfrm6_policy_init();
 415         if (ret)
 416                 goto out;
 417         ret = xfrm6_state_init();
 418         if (ret)
 419                 goto out_policy;
 420
 421         ret = xfrm6_protocol_init();
 422         if (ret)
 423                 goto out_state;
 424
 425         register_pernet_subsys(&xfrm6_net_ops);
 426 out:
 427         return ret;
 428 out_state:
 429         xfrm6_state_fini();
 430 out_policy:
 431         xfrm6_policy_fini();
 432         goto out;
 433 }
 434
 435 void xfrm6_fini(void)
 436 {
 437         unregister_pernet_subsys(&xfrm6_net_ops);
 438         xfrm6_protocol_fini();
 439         xfrm6_policy_fini();
 440         xfrm6_state_fini();
 441 }