SAFE public projects git trees. - safe/jmp/linux-2.6/blob - net/ipv6/netfilter/nf_conntrack_l3proto_ipv6.c

   1 /*
   2  * Copyright (C)2004 USAGI/WIDE Project
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * Author:
   9  *      Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
  10  *
  11  * 16 Dec 2003: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
  12  *      - support Layer 3 protocol independent connection tracking.
  13  *        Based on the original ip_conntrack code which had the following
  14  *        copyright information:
  15  *              (C) 1999-2001 Paul `Rusty' Russell
  16  *              (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
  17  *
  18  * 23 Mar 2004: Yasuyuki Kozakai @USAGI <yasuyuki.kozakai@toshiba.co.jp>
  19  *      - add get_features() to support various size of conntrack
  20  *        structures.
  21  */
  22
  23 #include <linux/config.h>
  24 #include <linux/types.h>
  25 #include <linux/ipv6.h>
  26 #include <linux/in6.h>
  27 #include <linux/netfilter.h>
  28 #include <linux/module.h>
  29 #include <linux/skbuff.h>
  30 #include <linux/icmp.h>
  31 #include <linux/sysctl.h>
  32 #include <net/ipv6.h>
  33
  34 #include <linux/netfilter_ipv6.h>
  35 #include <net/netfilter/nf_conntrack.h>
  36 #include <net/netfilter/nf_conntrack_helper.h>
  37 #include <net/netfilter/nf_conntrack_protocol.h>
  38 #include <net/netfilter/nf_conntrack_l3proto.h>
  39 #include <net/netfilter/nf_conntrack_core.h>
  40
  41 #if 0
  42 #define DEBUGP printk
  43 #else
  44 #define DEBUGP(format, args...)
  45 #endif
  46
  47 DECLARE_PER_CPU(struct ip_conntrack_stat, nf_conntrack_stat);
  48
  49 static int ipv6_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
  50                              struct nf_conntrack_tuple *tuple)
  51 {
  52         u_int32_t _addrs[8], *ap;
  53
  54         ap = skb_header_pointer(skb, nhoff + offsetof(struct ipv6hdr, saddr),
  55                                 sizeof(_addrs), _addrs);
  56         if (ap == NULL)
  57                 return 0;
  58
  59         memcpy(tuple->src.u3.ip6, ap, sizeof(tuple->src.u3.ip6));
  60         memcpy(tuple->dst.u3.ip6, ap + 4, sizeof(tuple->dst.u3.ip6));
  61
  62         return 1;
  63 }
  64
  65 static int ipv6_invert_tuple(struct nf_conntrack_tuple *tuple,
  66                              const struct nf_conntrack_tuple *orig)
  67 {
  68         memcpy(tuple->src.u3.ip6, orig->dst.u3.ip6, sizeof(tuple->src.u3.ip6));
  69         memcpy(tuple->dst.u3.ip6, orig->src.u3.ip6, sizeof(tuple->dst.u3.ip6));
  70
  71         return 1;
  72 }
  73
  74 static int ipv6_print_tuple(struct seq_file *s,
  75                             const struct nf_conntrack_tuple *tuple)
  76 {
  77         return seq_printf(s, "src=" NIP6_FMT " dst=" NIP6_FMT " ",
  78                           NIP6(*((struct in6_addr *)tuple->src.u3.ip6)),
  79                           NIP6(*((struct in6_addr *)tuple->dst.u3.ip6)));
  80 }
  81
  82 static int ipv6_print_conntrack(struct seq_file *s,
  83                                 const struct nf_conn *conntrack)
  84 {
  85         return 0;
  86 }
  87
  88 /*
  89  * Based on ipv6_skip_exthdr() in net/ipv6/exthdr.c
  90  *
  91  * This function parses (probably truncated) exthdr set "hdr"
  92  * of length "len". "nexthdrp" initially points to some place,
  93  * where type of the first header can be found.
  94  *
  95  * It skips all well-known exthdrs, and returns pointer to the start
  96  * of unparsable area i.e. the first header with unknown type.
  97  * if success, *nexthdr is updated by type/protocol of this header.
  98  *
  99  * NOTES: - it may return pointer pointing beyond end of packet,
 100  *          if the last recognized header is truncated in the middle.
 101  *        - if packet is truncated, so that all parsed headers are skipped,
 102  *          it returns -1.
 103  *        - if packet is fragmented, return pointer of the fragment header.
 104  *        - ESP is unparsable for now and considered like
 105  *          normal payload protocol.
 106  *        - Note also special handling of AUTH header. Thanks to IPsec wizards.
 107  */
 108
 109 int nf_ct_ipv6_skip_exthdr(struct sk_buff *skb, int start, u8 *nexthdrp,
 110                            int len)
 111 {
 112         u8 nexthdr = *nexthdrp;
 113
 114         while (ipv6_ext_hdr(nexthdr)) {
 115                 struct ipv6_opt_hdr hdr;
 116                 int hdrlen;
 117
 118                 if (len < (int)sizeof(struct ipv6_opt_hdr))
 119                         return -1;
 120                 if (nexthdr == NEXTHDR_NONE)
 121                         break;
 122                 if (nexthdr == NEXTHDR_FRAGMENT)
 123                         break;
 124                 if (skb_copy_bits(skb, start, &hdr, sizeof(hdr)))
 125                         BUG();
 126                 if (nexthdr == NEXTHDR_AUTH)
 127                         hdrlen = (hdr.hdrlen+2)<<2;
 128                 else
 129                         hdrlen = ipv6_optlen(&hdr);
 130
 131                 nexthdr = hdr.nexthdr;
 132                 len -= hdrlen;
 133                 start += hdrlen;
 134         }
 135
 136         *nexthdrp = nexthdr;
 137         return start;
 138 }
 139
 140 static int
 141 ipv6_prepare(struct sk_buff **pskb, unsigned int hooknum, unsigned int *dataoff,
 142              u_int8_t *protonum)
 143 {
 144         unsigned int extoff;
 145         unsigned char pnum;
 146         int protoff;
 147
 148         extoff = (u8*)((*pskb)->nh.ipv6h + 1) - (*pskb)->data;
 149         pnum = (*pskb)->nh.ipv6h->nexthdr;
 150
 151         protoff = nf_ct_ipv6_skip_exthdr(*pskb, extoff, &pnum,
 152                                          (*pskb)->len - extoff);
 153
 154         /*
 155          * (protoff == (*pskb)->len) mean that the packet doesn't have no data
 156          * except of IPv6 & ext headers. but it's tracked anyway. - YK
 157          */
 158         if ((protoff < 0) || (protoff > (*pskb)->len)) {
 159                 DEBUGP("ip6_conntrack_core: can't find proto in pkt\n");
 160                 NF_CT_STAT_INC(error);
 161                 NF_CT_STAT_INC(invalid);
 162                 return -NF_ACCEPT;
 163         }
 164
 165         *dataoff = protoff;
 166         *protonum = pnum;
 167         return NF_ACCEPT;
 168 }
 169
 170 static u_int32_t ipv6_get_features(const struct nf_conntrack_tuple *tuple)
 171 {
 172         return NF_CT_F_BASIC;
 173 }
 174
 175 static unsigned int ipv6_confirm(unsigned int hooknum,
 176                                  struct sk_buff **pskb,
 177                                  const struct net_device *in,
 178                                  const struct net_device *out,
 179                                  int (*okfn)(struct sk_buff *))
 180 {
 181         struct nf_conn *ct;
 182         struct nf_conn_help *help;
 183         enum ip_conntrack_info ctinfo;
 184         unsigned int ret, protoff;
 185         unsigned int extoff = (u8*)((*pskb)->nh.ipv6h + 1)
 186                               - (*pskb)->data;
 187         unsigned char pnum = (*pskb)->nh.ipv6h->nexthdr;
 188
 189
 190         /* This is where we call the helper: as the packet goes out. */
 191         ct = nf_ct_get(*pskb, &ctinfo);
 192         if (!ct)
 193                 goto out;
 194
 195         help = nfct_help(ct);
 196         if (!help || !help->helper)
 197                 goto out;
 198
 199         protoff = nf_ct_ipv6_skip_exthdr(*pskb, extoff, &pnum,
 200                                          (*pskb)->len - extoff);
 201         if (protoff < 0 || protoff > (*pskb)->len ||
 202             pnum == NEXTHDR_FRAGMENT) {
 203                 DEBUGP("proto header not found\n");
 204                 return NF_ACCEPT;
 205         }
 206
 207         ret = help->helper->help(pskb, protoff, ct, ctinfo);
 208         if (ret != NF_ACCEPT)
 209                 return ret;
 210 out:
 211         /* We've seen it coming out the other side: confirm it */
 212         return nf_conntrack_confirm(pskb);
 213 }
 214
 215 extern struct sk_buff *nf_ct_frag6_gather(struct sk_buff *skb);
 216 extern void nf_ct_frag6_output(unsigned int hooknum, struct sk_buff *skb,
 217                                struct net_device *in,
 218                                struct net_device *out,
 219                                int (*okfn)(struct sk_buff *));
 220 static unsigned int ipv6_defrag(unsigned int hooknum,
 221                                 struct sk_buff **pskb,
 222                                 const struct net_device *in,
 223                                 const struct net_device *out,
 224                                 int (*okfn)(struct sk_buff *))
 225 {
 226         struct sk_buff *reasm;
 227
 228         /* Previously seen (loopback)?  */
 229         if ((*pskb)->nfct)
 230                 return NF_ACCEPT;
 231
 232         reasm = nf_ct_frag6_gather(*pskb);
 233
 234         /* queued */
 235         if (reasm == NULL)
 236                 return NF_STOLEN;
 237
 238         /* error occured or not fragmented */
 239         if (reasm == *pskb)
 240                 return NF_ACCEPT;
 241
 242         nf_ct_frag6_output(hooknum, reasm, (struct net_device *)in,
 243                            (struct net_device *)out, okfn);
 244
 245         return NF_STOLEN;
 246 }
 247
 248 static unsigned int ipv6_conntrack_in(unsigned int hooknum,
 249                                       struct sk_buff **pskb,
 250                                       const struct net_device *in,
 251                                       const struct net_device *out,
 252                                       int (*okfn)(struct sk_buff *))
 253 {
 254         struct sk_buff *reasm = (*pskb)->nfct_reasm;
 255
 256         /* This packet is fragmented and has reassembled packet. */
 257         if (reasm) {
 258                 /* Reassembled packet isn't parsed yet ? */
 259                 if (!reasm->nfct) {
 260                         unsigned int ret;
 261
 262                         ret = nf_conntrack_in(PF_INET6, hooknum, &reasm);
 263                         if (ret != NF_ACCEPT)
 264                                 return ret;
 265                 }
 266                 nf_conntrack_get(reasm->nfct);
 267                 (*pskb)->nfct = reasm->nfct;
 268                 return NF_ACCEPT;
 269         }
 270
 271         return nf_conntrack_in(PF_INET6, hooknum, pskb);
 272 }
 273
 274 static unsigned int ipv6_conntrack_local(unsigned int hooknum,
 275                                          struct sk_buff **pskb,
 276                                          const struct net_device *in,
 277                                          const struct net_device *out,
 278                                          int (*okfn)(struct sk_buff *))
 279 {
 280         /* root is playing with raw sockets. */
 281         if ((*pskb)->len < sizeof(struct ipv6hdr)) {
 282                 if (net_ratelimit())
 283                         printk("ipv6_conntrack_local: packet too short\n");
 284                 return NF_ACCEPT;
 285         }
 286         return ipv6_conntrack_in(hooknum, pskb, in, out, okfn);
 287 }
 288
 289 static struct nf_hook_ops ipv6_conntrack_ops[] = {
 290         {
 291                 .hook           = ipv6_defrag,
 292                 .owner          = THIS_MODULE,
 293                 .pf             = PF_INET6,
 294                 .hooknum        = NF_IP6_PRE_ROUTING,
 295                 .priority       = NF_IP6_PRI_CONNTRACK_DEFRAG,
 296         },
 297         {
 298                 .hook           = ipv6_conntrack_in,
 299                 .owner          = THIS_MODULE,
 300                 .pf             = PF_INET6,
 301                 .hooknum        = NF_IP6_PRE_ROUTING,
 302                 .priority       = NF_IP6_PRI_CONNTRACK,
 303         },
 304         {
 305                 .hook           = ipv6_conntrack_local,
 306                 .owner          = THIS_MODULE,
 307                 .pf             = PF_INET6,
 308                 .hooknum        = NF_IP6_LOCAL_OUT,
 309                 .priority       = NF_IP6_PRI_CONNTRACK,
 310         },
 311         {
 312                 .hook           = ipv6_defrag,
 313                 .owner          = THIS_MODULE,
 314                 .pf             = PF_INET6,
 315                 .hooknum        = NF_IP6_LOCAL_OUT,
 316                 .priority       = NF_IP6_PRI_CONNTRACK_DEFRAG,
 317         },
 318         {
 319                 .hook           = ipv6_confirm,
 320                 .owner          = THIS_MODULE,
 321                 .pf             = PF_INET6,
 322                 .hooknum        = NF_IP6_POST_ROUTING,
 323                 .priority       = NF_IP6_PRI_LAST,
 324         },
 325         {
 326                 .hook           = ipv6_confirm,
 327                 .owner          = THIS_MODULE,
 328                 .pf             = PF_INET6,
 329                 .hooknum        = NF_IP6_LOCAL_IN,
 330                 .priority       = NF_IP6_PRI_LAST-1,
 331         },
 332 };
 333
 334 #ifdef CONFIG_SYSCTL
 335
 336 /* From nf_conntrack_proto_icmpv6.c */
 337 extern unsigned int nf_ct_icmpv6_timeout;
 338
 339 /* From nf_conntrack_frag6.c */
 340 extern unsigned int nf_ct_frag6_timeout;
 341 extern unsigned int nf_ct_frag6_low_thresh;
 342 extern unsigned int nf_ct_frag6_high_thresh;
 343
 344 static struct ctl_table_header *nf_ct_ipv6_sysctl_header;
 345
 346 static ctl_table nf_ct_sysctl_table[] = {
 347         {
 348                 .ctl_name       = NET_NF_CONNTRACK_ICMPV6_TIMEOUT,
 349                 .procname       = "nf_conntrack_icmpv6_timeout",
 350                 .data           = &nf_ct_icmpv6_timeout,
 351                 .maxlen         = sizeof(unsigned int),
 352                 .mode           = 0644,
 353                 .proc_handler   = &proc_dointvec_jiffies,
 354         },
 355         {
 356                 .ctl_name       = NET_NF_CONNTRACK_FRAG6_TIMEOUT,
 357                 .procname       = "nf_conntrack_frag6_timeout",
 358                 .data           = &nf_ct_frag6_timeout,
 359                 .maxlen         = sizeof(unsigned int),
 360                 .mode           = 0644,
 361                 .proc_handler   = &proc_dointvec_jiffies,
 362         },
 363         {
 364                 .ctl_name       = NET_NF_CONNTRACK_FRAG6_LOW_THRESH,
 365                 .procname       = "nf_conntrack_frag6_low_thresh",
 366                 .data           = &nf_ct_frag6_low_thresh,
 367                 .maxlen         = sizeof(unsigned int),
 368                 .mode           = 0644,
 369                 .proc_handler   = &proc_dointvec,
 370         },
 371         {
 372                 .ctl_name       = NET_NF_CONNTRACK_FRAG6_HIGH_THRESH,
 373                 .procname       = "nf_conntrack_frag6_high_thresh",
 374                 .data           = &nf_ct_frag6_high_thresh,
 375                 .maxlen         = sizeof(unsigned int),
 376                 .mode           = 0644,
 377                 .proc_handler   = &proc_dointvec,
 378         },
 379         { .ctl_name = 0 }
 380 };
 381
 382 static ctl_table nf_ct_netfilter_table[] = {
 383         {
 384                 .ctl_name       = NET_NETFILTER,
 385                 .procname       = "netfilter",
 386                 .mode           = 0555,
 387                 .child          = nf_ct_sysctl_table,
 388         },
 389         { .ctl_name = 0 }
 390 };
 391
 392 static ctl_table nf_ct_net_table[] = {
 393         {
 394                 .ctl_name       = CTL_NET,
 395                 .procname       = "net",
 396                 .mode           = 0555,
 397                 .child          = nf_ct_netfilter_table,
 398         },
 399         { .ctl_name = 0 }
 400 };
 401 #endif
 402
 403 #if defined(CONFIG_NF_CT_NETLINK) || \
 404     defined(CONFIG_NF_CT_NETLINK_MODULE)
 405
 406 #include <linux/netfilter/nfnetlink.h>
 407 #include <linux/netfilter/nfnetlink_conntrack.h>
 408
 409 static int ipv6_tuple_to_nfattr(struct sk_buff *skb,
 410                                 const struct nf_conntrack_tuple *tuple)
 411 {
 412         NFA_PUT(skb, CTA_IP_V6_SRC, sizeof(u_int32_t) * 4,
 413                 &tuple->src.u3.ip6);
 414         NFA_PUT(skb, CTA_IP_V6_DST, sizeof(u_int32_t) * 4,
 415                 &tuple->dst.u3.ip6);
 416         return 0;
 417
 418 nfattr_failure:
 419         return -1;
 420 }
 421
 422 static const size_t cta_min_ip[CTA_IP_MAX] = {
 423         [CTA_IP_V6_SRC-1]       = sizeof(u_int32_t)*4,
 424         [CTA_IP_V6_DST-1]       = sizeof(u_int32_t)*4,
 425 };
 426
 427 static int ipv6_nfattr_to_tuple(struct nfattr *tb[],
 428                                 struct nf_conntrack_tuple *t)
 429 {
 430         if (!tb[CTA_IP_V6_SRC-1] || !tb[CTA_IP_V6_DST-1])
 431                 return -EINVAL;
 432
 433         if (nfattr_bad_size(tb, CTA_IP_MAX, cta_min_ip))
 434                 return -EINVAL;
 435
 436         memcpy(&t->src.u3.ip6, NFA_DATA(tb[CTA_IP_V6_SRC-1]),
 437                sizeof(u_int32_t) * 4);
 438         memcpy(&t->dst.u3.ip6, NFA_DATA(tb[CTA_IP_V6_DST-1]),
 439                sizeof(u_int32_t) * 4);
 440
 441         return 0;
 442 }
 443 #endif
 444
 445 struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv6 = {
 446         .l3proto                = PF_INET6,
 447         .name                   = "ipv6",
 448         .pkt_to_tuple           = ipv6_pkt_to_tuple,
 449         .invert_tuple           = ipv6_invert_tuple,
 450         .print_tuple            = ipv6_print_tuple,
 451         .print_conntrack        = ipv6_print_conntrack,
 452         .prepare                = ipv6_prepare,
 453 #if defined(CONFIG_NF_CT_NETLINK) || \
 454     defined(CONFIG_NF_CT_NETLINK_MODULE)
 455         .tuple_to_nfattr        = ipv6_tuple_to_nfattr,
 456         .nfattr_to_tuple        = ipv6_nfattr_to_tuple,
 457 #endif
 458         .get_features           = ipv6_get_features,
 459         .me                     = THIS_MODULE,
 460 };
 461
 462 extern struct nf_conntrack_protocol nf_conntrack_protocol_tcp6;
 463 extern struct nf_conntrack_protocol nf_conntrack_protocol_udp6;
 464 extern struct nf_conntrack_protocol nf_conntrack_protocol_icmpv6;
 465 extern int nf_ct_frag6_init(void);
 466 extern void nf_ct_frag6_cleanup(void);
 467
 468 MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET6));
 469 MODULE_LICENSE("GPL");
 470 MODULE_AUTHOR("Yasuyuki KOZAKAI @USAGI <yasuyuki.kozakai@toshiba.co.jp>");
 471
 472 static int __init nf_conntrack_l3proto_ipv6_init(void)
 473 {
 474         int ret = 0;
 475
 476         need_conntrack();
 477
 478         ret = nf_ct_frag6_init();
 479         if (ret < 0) {
 480                 printk("nf_conntrack_ipv6: can't initialize frag6.\n");
 481                 return ret;
 482         }
 483         ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_tcp6);
 484         if (ret < 0) {
 485                 printk("nf_conntrack_ipv6: can't register tcp.\n");
 486                 goto cleanup_frag6;
 487         }
 488
 489         ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_udp6);
 490         if (ret < 0) {
 491                 printk("nf_conntrack_ipv6: can't register udp.\n");
 492                 goto cleanup_tcp;
 493         }
 494
 495         ret = nf_conntrack_protocol_register(&nf_conntrack_protocol_icmpv6);
 496         if (ret < 0) {
 497                 printk("nf_conntrack_ipv6: can't register icmpv6.\n");
 498                 goto cleanup_udp;
 499         }
 500
 501         ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv6);
 502         if (ret < 0) {
 503                 printk("nf_conntrack_ipv6: can't register ipv6\n");
 504                 goto cleanup_icmpv6;
 505         }
 506
 507         ret = nf_register_hooks(ipv6_conntrack_ops,
 508                                 ARRAY_SIZE(ipv6_conntrack_ops));
 509         if (ret < 0) {
 510                 printk("nf_conntrack_ipv6: can't register pre-routing defrag "
 511                        "hook.\n");
 512                 goto cleanup_ipv6;
 513         }
 514 #ifdef CONFIG_SYSCTL
 515         nf_ct_ipv6_sysctl_header = register_sysctl_table(nf_ct_net_table, 0);
 516         if (nf_ct_ipv6_sysctl_header == NULL) {
 517                 printk("nf_conntrack: can't register to sysctl.\n");
 518                 ret = -ENOMEM;
 519                 goto cleanup_hooks;
 520         }
 521 #endif
 522         return ret;
 523
 524 #ifdef CONFIG_SYSCTL
 525  cleanup_hooks:
 526         nf_unregister_hooks(ipv6_conntrack_ops, ARRAY_SIZE(ipv6_conntrack_ops));
 527 #endif
 528  cleanup_ipv6:
 529         nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv6);
 530  cleanup_icmpv6:
 531         nf_conntrack_protocol_unregister(&nf_conntrack_protocol_icmpv6);
 532  cleanup_udp:
 533         nf_conntrack_protocol_unregister(&nf_conntrack_protocol_udp6);
 534  cleanup_tcp:
 535         nf_conntrack_protocol_unregister(&nf_conntrack_protocol_tcp6);
 536  cleanup_frag6:
 537         nf_ct_frag6_cleanup();
 538         return ret;
 539 }
 540
 541 static void __exit nf_conntrack_l3proto_ipv6_fini(void)
 542 {
 543         synchronize_net();
 544 #ifdef CONFIG_SYSCTL
 545         unregister_sysctl_table(nf_ct_ipv6_sysctl_header);
 546 #endif
 547         nf_unregister_hooks(ipv6_conntrack_ops, ARRAY_SIZE(ipv6_conntrack_ops));
 548         nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv6);
 549         nf_conntrack_protocol_unregister(&nf_conntrack_protocol_icmpv6);
 550         nf_conntrack_protocol_unregister(&nf_conntrack_protocol_udp6);
 551         nf_conntrack_protocol_unregister(&nf_conntrack_protocol_tcp6);
 552         nf_ct_frag6_cleanup();
 553 }
 554
 555 module_init(nf_conntrack_l3proto_ipv6_init);
 556 module_exit(nf_conntrack_l3proto_ipv6_fini);