| 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/types.h> |
| 24 | #include <linux/ipv6.h> |
| 25 | #include <linux/in6.h> |
| 26 | #include <linux/netfilter.h> |
| 27 | #include <linux/module.h> |
| 28 | #include <linux/skbuff.h> |
| 29 | #include <linux/icmp.h> |
| 30 | #include <linux/sysctl.h> |
| 31 | #include <net/ipv6.h> |
| 32 | |
| 33 | #include <linux/netfilter_ipv6.h> |
| 34 | #include <net/netfilter/nf_conntrack.h> |
| 35 | #include <net/netfilter/nf_conntrack_helper.h> |
| 36 | #include <net/netfilter/nf_conntrack_l4proto.h> |
| 37 | #include <net/netfilter/nf_conntrack_l3proto.h> |
| 38 | #include <net/netfilter/nf_conntrack_core.h> |
| 39 | |
| 40 | #if 0 |
| 41 | #define DEBUGP printk |
| 42 | #else |
| 43 | #define DEBUGP(format, args...) |
| 44 | #endif |
| 45 | |
| 46 | static int ipv6_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff, |
| 47 | struct nf_conntrack_tuple *tuple) |
| 48 | { |
| 49 | u_int32_t _addrs[8], *ap; |
| 50 | |
| 51 | ap = skb_header_pointer(skb, nhoff + offsetof(struct ipv6hdr, saddr), |
| 52 | sizeof(_addrs), _addrs); |
| 53 | if (ap == NULL) |
| 54 | return 0; |
| 55 | |
| 56 | memcpy(tuple->src.u3.ip6, ap, sizeof(tuple->src.u3.ip6)); |
| 57 | memcpy(tuple->dst.u3.ip6, ap + 4, sizeof(tuple->dst.u3.ip6)); |
| 58 | |
| 59 | return 1; |
| 60 | } |
| 61 | |
| 62 | static int ipv6_invert_tuple(struct nf_conntrack_tuple *tuple, |
| 63 | const struct nf_conntrack_tuple *orig) |
| 64 | { |
| 65 | memcpy(tuple->src.u3.ip6, orig->dst.u3.ip6, sizeof(tuple->src.u3.ip6)); |
| 66 | memcpy(tuple->dst.u3.ip6, orig->src.u3.ip6, sizeof(tuple->dst.u3.ip6)); |
| 67 | |
| 68 | return 1; |
| 69 | } |
| 70 | |
| 71 | static int ipv6_print_tuple(struct seq_file *s, |
| 72 | const struct nf_conntrack_tuple *tuple) |
| 73 | { |
| 74 | return seq_printf(s, "src=" NIP6_FMT " dst=" NIP6_FMT " ", |
| 75 | NIP6(*((struct in6_addr *)tuple->src.u3.ip6)), |
| 76 | NIP6(*((struct in6_addr *)tuple->dst.u3.ip6))); |
| 77 | } |
| 78 | |
| 79 | static int ipv6_print_conntrack(struct seq_file *s, |
| 80 | const struct nf_conn *conntrack) |
| 81 | { |
| 82 | return 0; |
| 83 | } |
| 84 | |
| 85 | /* |
| 86 | * Based on ipv6_skip_exthdr() in net/ipv6/exthdr.c |
| 87 | * |
| 88 | * This function parses (probably truncated) exthdr set "hdr" |
| 89 | * of length "len". "nexthdrp" initially points to some place, |
| 90 | * where type of the first header can be found. |
| 91 | * |
| 92 | * It skips all well-known exthdrs, and returns pointer to the start |
| 93 | * of unparsable area i.e. the first header with unknown type. |
| 94 | * if success, *nexthdr is updated by type/protocol of this header. |
| 95 | * |
| 96 | * NOTES: - it may return pointer pointing beyond end of packet, |
| 97 | * if the last recognized header is truncated in the middle. |
| 98 | * - if packet is truncated, so that all parsed headers are skipped, |
| 99 | * it returns -1. |
| 100 | * - if packet is fragmented, return pointer of the fragment header. |
| 101 | * - ESP is unparsable for now and considered like |
| 102 | * normal payload protocol. |
| 103 | * - Note also special handling of AUTH header. Thanks to IPsec wizards. |
| 104 | */ |
| 105 | |
| 106 | int nf_ct_ipv6_skip_exthdr(struct sk_buff *skb, int start, u8 *nexthdrp, |
| 107 | int len) |
| 108 | { |
| 109 | u8 nexthdr = *nexthdrp; |
| 110 | |
| 111 | while (ipv6_ext_hdr(nexthdr)) { |
| 112 | struct ipv6_opt_hdr hdr; |
| 113 | int hdrlen; |
| 114 | |
| 115 | if (len < (int)sizeof(struct ipv6_opt_hdr)) |
| 116 | return -1; |
| 117 | if (nexthdr == NEXTHDR_NONE) |
| 118 | break; |
| 119 | if (nexthdr == NEXTHDR_FRAGMENT) |
| 120 | break; |
| 121 | if (skb_copy_bits(skb, start, &hdr, sizeof(hdr))) |
| 122 | BUG(); |
| 123 | if (nexthdr == NEXTHDR_AUTH) |
| 124 | hdrlen = (hdr.hdrlen+2)<<2; |
| 125 | else |
| 126 | hdrlen = ipv6_optlen(&hdr); |
| 127 | |
| 128 | nexthdr = hdr.nexthdr; |
| 129 | len -= hdrlen; |
| 130 | start += hdrlen; |
| 131 | } |
| 132 | |
| 133 | *nexthdrp = nexthdr; |
| 134 | return start; |
| 135 | } |
| 136 | |
| 137 | static int |
| 138 | ipv6_prepare(struct sk_buff **pskb, unsigned int hooknum, unsigned int *dataoff, |
| 139 | u_int8_t *protonum) |
| 140 | { |
| 141 | unsigned int extoff; |
| 142 | unsigned char pnum; |
| 143 | int protoff; |
| 144 | |
| 145 | extoff = (u8*)((*pskb)->nh.ipv6h + 1) - (*pskb)->data; |
| 146 | pnum = (*pskb)->nh.ipv6h->nexthdr; |
| 147 | |
| 148 | protoff = nf_ct_ipv6_skip_exthdr(*pskb, extoff, &pnum, |
| 149 | (*pskb)->len - extoff); |
| 150 | |
| 151 | /* |
| 152 | * (protoff == (*pskb)->len) mean that the packet doesn't have no data |
| 153 | * except of IPv6 & ext headers. but it's tracked anyway. - YK |
| 154 | */ |
| 155 | if ((protoff < 0) || (protoff > (*pskb)->len)) { |
| 156 | DEBUGP("ip6_conntrack_core: can't find proto in pkt\n"); |
| 157 | NF_CT_STAT_INC(error); |
| 158 | NF_CT_STAT_INC(invalid); |
| 159 | return -NF_ACCEPT; |
| 160 | } |
| 161 | |
| 162 | *dataoff = protoff; |
| 163 | *protonum = pnum; |
| 164 | return NF_ACCEPT; |
| 165 | } |
| 166 | |
| 167 | static u_int32_t ipv6_get_features(const struct nf_conntrack_tuple *tuple) |
| 168 | { |
| 169 | return NF_CT_F_BASIC; |
| 170 | } |
| 171 | |
| 172 | static unsigned int ipv6_confirm(unsigned int hooknum, |
| 173 | struct sk_buff **pskb, |
| 174 | const struct net_device *in, |
| 175 | const struct net_device *out, |
| 176 | int (*okfn)(struct sk_buff *)) |
| 177 | { |
| 178 | struct nf_conn *ct; |
| 179 | struct nf_conn_help *help; |
| 180 | enum ip_conntrack_info ctinfo; |
| 181 | unsigned int ret, protoff; |
| 182 | unsigned int extoff = (u8*)((*pskb)->nh.ipv6h + 1) |
| 183 | - (*pskb)->data; |
| 184 | unsigned char pnum = (*pskb)->nh.ipv6h->nexthdr; |
| 185 | |
| 186 | |
| 187 | /* This is where we call the helper: as the packet goes out. */ |
| 188 | ct = nf_ct_get(*pskb, &ctinfo); |
| 189 | if (!ct || ctinfo == IP_CT_RELATED + IP_CT_IS_REPLY) |
| 190 | goto out; |
| 191 | |
| 192 | help = nfct_help(ct); |
| 193 | if (!help || !help->helper) |
| 194 | goto out; |
| 195 | |
| 196 | protoff = nf_ct_ipv6_skip_exthdr(*pskb, extoff, &pnum, |
| 197 | (*pskb)->len - extoff); |
| 198 | if (protoff < 0 || protoff > (*pskb)->len || |
| 199 | pnum == NEXTHDR_FRAGMENT) { |
| 200 | DEBUGP("proto header not found\n"); |
| 201 | return NF_ACCEPT; |
| 202 | } |
| 203 | |
| 204 | ret = help->helper->help(pskb, protoff, ct, ctinfo); |
| 205 | if (ret != NF_ACCEPT) |
| 206 | return ret; |
| 207 | out: |
| 208 | /* We've seen it coming out the other side: confirm it */ |
| 209 | return nf_conntrack_confirm(pskb); |
| 210 | } |
| 211 | |
| 212 | static unsigned int ipv6_defrag(unsigned int hooknum, |
| 213 | struct sk_buff **pskb, |
| 214 | const struct net_device *in, |
| 215 | const struct net_device *out, |
| 216 | int (*okfn)(struct sk_buff *)) |
| 217 | { |
| 218 | struct sk_buff *reasm; |
| 219 | |
| 220 | /* Previously seen (loopback)? */ |
| 221 | if ((*pskb)->nfct) |
| 222 | return NF_ACCEPT; |
| 223 | |
| 224 | reasm = nf_ct_frag6_gather(*pskb); |
| 225 | |
| 226 | /* queued */ |
| 227 | if (reasm == NULL) |
| 228 | return NF_STOLEN; |
| 229 | |
| 230 | /* error occured or not fragmented */ |
| 231 | if (reasm == *pskb) |
| 232 | return NF_ACCEPT; |
| 233 | |
| 234 | nf_ct_frag6_output(hooknum, reasm, (struct net_device *)in, |
| 235 | (struct net_device *)out, okfn); |
| 236 | |
| 237 | return NF_STOLEN; |
| 238 | } |
| 239 | |
| 240 | static unsigned int ipv6_conntrack_in(unsigned int hooknum, |
| 241 | struct sk_buff **pskb, |
| 242 | const struct net_device *in, |
| 243 | const struct net_device *out, |
| 244 | int (*okfn)(struct sk_buff *)) |
| 245 | { |
| 246 | struct sk_buff *reasm = (*pskb)->nfct_reasm; |
| 247 | |
| 248 | /* This packet is fragmented and has reassembled packet. */ |
| 249 | if (reasm) { |
| 250 | /* Reassembled packet isn't parsed yet ? */ |
| 251 | if (!reasm->nfct) { |
| 252 | unsigned int ret; |
| 253 | |
| 254 | ret = nf_conntrack_in(PF_INET6, hooknum, &reasm); |
| 255 | if (ret != NF_ACCEPT) |
| 256 | return ret; |
| 257 | } |
| 258 | nf_conntrack_get(reasm->nfct); |
| 259 | (*pskb)->nfct = reasm->nfct; |
| 260 | return NF_ACCEPT; |
| 261 | } |
| 262 | |
| 263 | return nf_conntrack_in(PF_INET6, hooknum, pskb); |
| 264 | } |
| 265 | |
| 266 | static unsigned int ipv6_conntrack_local(unsigned int hooknum, |
| 267 | struct sk_buff **pskb, |
| 268 | const struct net_device *in, |
| 269 | const struct net_device *out, |
| 270 | int (*okfn)(struct sk_buff *)) |
| 271 | { |
| 272 | /* root is playing with raw sockets. */ |
| 273 | if ((*pskb)->len < sizeof(struct ipv6hdr)) { |
| 274 | if (net_ratelimit()) |
| 275 | printk("ipv6_conntrack_local: packet too short\n"); |
| 276 | return NF_ACCEPT; |
| 277 | } |
| 278 | return ipv6_conntrack_in(hooknum, pskb, in, out, okfn); |
| 279 | } |
| 280 | |
| 281 | static struct nf_hook_ops ipv6_conntrack_ops[] = { |
| 282 | { |
| 283 | .hook = ipv6_defrag, |
| 284 | .owner = THIS_MODULE, |
| 285 | .pf = PF_INET6, |
| 286 | .hooknum = NF_IP6_PRE_ROUTING, |
| 287 | .priority = NF_IP6_PRI_CONNTRACK_DEFRAG, |
| 288 | }, |
| 289 | { |
| 290 | .hook = ipv6_conntrack_in, |
| 291 | .owner = THIS_MODULE, |
| 292 | .pf = PF_INET6, |
| 293 | .hooknum = NF_IP6_PRE_ROUTING, |
| 294 | .priority = NF_IP6_PRI_CONNTRACK, |
| 295 | }, |
| 296 | { |
| 297 | .hook = ipv6_conntrack_local, |
| 298 | .owner = THIS_MODULE, |
| 299 | .pf = PF_INET6, |
| 300 | .hooknum = NF_IP6_LOCAL_OUT, |
| 301 | .priority = NF_IP6_PRI_CONNTRACK, |
| 302 | }, |
| 303 | { |
| 304 | .hook = ipv6_defrag, |
| 305 | .owner = THIS_MODULE, |
| 306 | .pf = PF_INET6, |
| 307 | .hooknum = NF_IP6_LOCAL_OUT, |
| 308 | .priority = NF_IP6_PRI_CONNTRACK_DEFRAG, |
| 309 | }, |
| 310 | { |
| 311 | .hook = ipv6_confirm, |
| 312 | .owner = THIS_MODULE, |
| 313 | .pf = PF_INET6, |
| 314 | .hooknum = NF_IP6_POST_ROUTING, |
| 315 | .priority = NF_IP6_PRI_LAST, |
| 316 | }, |
| 317 | { |
| 318 | .hook = ipv6_confirm, |
| 319 | .owner = THIS_MODULE, |
| 320 | .pf = PF_INET6, |
| 321 | .hooknum = NF_IP6_LOCAL_IN, |
| 322 | .priority = NF_IP6_PRI_LAST-1, |
| 323 | }, |
| 324 | }; |
| 325 | |
| 326 | #ifdef CONFIG_SYSCTL |
| 327 | static ctl_table nf_ct_ipv6_sysctl_table[] = { |
| 328 | { |
| 329 | .ctl_name = NET_NF_CONNTRACK_FRAG6_TIMEOUT, |
| 330 | .procname = "nf_conntrack_frag6_timeout", |
| 331 | .data = &nf_ct_frag6_timeout, |
| 332 | .maxlen = sizeof(unsigned int), |
| 333 | .mode = 0644, |
| 334 | .proc_handler = &proc_dointvec_jiffies, |
| 335 | }, |
| 336 | { |
| 337 | .ctl_name = NET_NF_CONNTRACK_FRAG6_LOW_THRESH, |
| 338 | .procname = "nf_conntrack_frag6_low_thresh", |
| 339 | .data = &nf_ct_frag6_low_thresh, |
| 340 | .maxlen = sizeof(unsigned int), |
| 341 | .mode = 0644, |
| 342 | .proc_handler = &proc_dointvec, |
| 343 | }, |
| 344 | { |
| 345 | .ctl_name = NET_NF_CONNTRACK_FRAG6_HIGH_THRESH, |
| 346 | .procname = "nf_conntrack_frag6_high_thresh", |
| 347 | .data = &nf_ct_frag6_high_thresh, |
| 348 | .maxlen = sizeof(unsigned int), |
| 349 | .mode = 0644, |
| 350 | .proc_handler = &proc_dointvec, |
| 351 | }, |
| 352 | { .ctl_name = 0 } |
| 353 | }; |
| 354 | #endif |
| 355 | |
| 356 | #if defined(CONFIG_NF_CT_NETLINK) || \ |
| 357 | defined(CONFIG_NF_CT_NETLINK_MODULE) |
| 358 | |
| 359 | #include <linux/netfilter/nfnetlink.h> |
| 360 | #include <linux/netfilter/nfnetlink_conntrack.h> |
| 361 | |
| 362 | static int ipv6_tuple_to_nfattr(struct sk_buff *skb, |
| 363 | const struct nf_conntrack_tuple *tuple) |
| 364 | { |
| 365 | NFA_PUT(skb, CTA_IP_V6_SRC, sizeof(u_int32_t) * 4, |
| 366 | &tuple->src.u3.ip6); |
| 367 | NFA_PUT(skb, CTA_IP_V6_DST, sizeof(u_int32_t) * 4, |
| 368 | &tuple->dst.u3.ip6); |
| 369 | return 0; |
| 370 | |
| 371 | nfattr_failure: |
| 372 | return -1; |
| 373 | } |
| 374 | |
| 375 | static const size_t cta_min_ip[CTA_IP_MAX] = { |
| 376 | [CTA_IP_V6_SRC-1] = sizeof(u_int32_t)*4, |
| 377 | [CTA_IP_V6_DST-1] = sizeof(u_int32_t)*4, |
| 378 | }; |
| 379 | |
| 380 | static int ipv6_nfattr_to_tuple(struct nfattr *tb[], |
| 381 | struct nf_conntrack_tuple *t) |
| 382 | { |
| 383 | if (!tb[CTA_IP_V6_SRC-1] || !tb[CTA_IP_V6_DST-1]) |
| 384 | return -EINVAL; |
| 385 | |
| 386 | if (nfattr_bad_size(tb, CTA_IP_MAX, cta_min_ip)) |
| 387 | return -EINVAL; |
| 388 | |
| 389 | memcpy(&t->src.u3.ip6, NFA_DATA(tb[CTA_IP_V6_SRC-1]), |
| 390 | sizeof(u_int32_t) * 4); |
| 391 | memcpy(&t->dst.u3.ip6, NFA_DATA(tb[CTA_IP_V6_DST-1]), |
| 392 | sizeof(u_int32_t) * 4); |
| 393 | |
| 394 | return 0; |
| 395 | } |
| 396 | #endif |
| 397 | |
| 398 | struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv6 = { |
| 399 | .l3proto = PF_INET6, |
| 400 | .name = "ipv6", |
| 401 | .pkt_to_tuple = ipv6_pkt_to_tuple, |
| 402 | .invert_tuple = ipv6_invert_tuple, |
| 403 | .print_tuple = ipv6_print_tuple, |
| 404 | .print_conntrack = ipv6_print_conntrack, |
| 405 | .prepare = ipv6_prepare, |
| 406 | #if defined(CONFIG_NF_CT_NETLINK) || \ |
| 407 | defined(CONFIG_NF_CT_NETLINK_MODULE) |
| 408 | .tuple_to_nfattr = ipv6_tuple_to_nfattr, |
| 409 | .nfattr_to_tuple = ipv6_nfattr_to_tuple, |
| 410 | #endif |
| 411 | #ifdef CONFIG_SYSCTL |
| 412 | .ctl_table_path = nf_net_netfilter_sysctl_path, |
| 413 | .ctl_table = nf_ct_ipv6_sysctl_table, |
| 414 | #endif |
| 415 | .get_features = ipv6_get_features, |
| 416 | .me = THIS_MODULE, |
| 417 | }; |
| 418 | |
| 419 | MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET6)); |
| 420 | MODULE_LICENSE("GPL"); |
| 421 | MODULE_AUTHOR("Yasuyuki KOZAKAI @USAGI <yasuyuki.kozakai@toshiba.co.jp>"); |
| 422 | |
| 423 | static int __init nf_conntrack_l3proto_ipv6_init(void) |
| 424 | { |
| 425 | int ret = 0; |
| 426 | |
| 427 | need_conntrack(); |
| 428 | |
| 429 | ret = nf_ct_frag6_init(); |
| 430 | if (ret < 0) { |
| 431 | printk("nf_conntrack_ipv6: can't initialize frag6.\n"); |
| 432 | return ret; |
| 433 | } |
| 434 | ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_tcp6); |
| 435 | if (ret < 0) { |
| 436 | printk("nf_conntrack_ipv6: can't register tcp.\n"); |
| 437 | goto cleanup_frag6; |
| 438 | } |
| 439 | |
| 440 | ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_udp6); |
| 441 | if (ret < 0) { |
| 442 | printk("nf_conntrack_ipv6: can't register udp.\n"); |
| 443 | goto cleanup_tcp; |
| 444 | } |
| 445 | |
| 446 | ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_icmpv6); |
| 447 | if (ret < 0) { |
| 448 | printk("nf_conntrack_ipv6: can't register icmpv6.\n"); |
| 449 | goto cleanup_udp; |
| 450 | } |
| 451 | |
| 452 | ret = nf_conntrack_l3proto_register(&nf_conntrack_l3proto_ipv6); |
| 453 | if (ret < 0) { |
| 454 | printk("nf_conntrack_ipv6: can't register ipv6\n"); |
| 455 | goto cleanup_icmpv6; |
| 456 | } |
| 457 | |
| 458 | ret = nf_register_hooks(ipv6_conntrack_ops, |
| 459 | ARRAY_SIZE(ipv6_conntrack_ops)); |
| 460 | if (ret < 0) { |
| 461 | printk("nf_conntrack_ipv6: can't register pre-routing defrag " |
| 462 | "hook.\n"); |
| 463 | goto cleanup_ipv6; |
| 464 | } |
| 465 | return ret; |
| 466 | |
| 467 | cleanup_ipv6: |
| 468 | nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv6); |
| 469 | cleanup_icmpv6: |
| 470 | nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmpv6); |
| 471 | cleanup_udp: |
| 472 | nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp6); |
| 473 | cleanup_tcp: |
| 474 | nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp6); |
| 475 | cleanup_frag6: |
| 476 | nf_ct_frag6_cleanup(); |
| 477 | return ret; |
| 478 | } |
| 479 | |
| 480 | static void __exit nf_conntrack_l3proto_ipv6_fini(void) |
| 481 | { |
| 482 | synchronize_net(); |
| 483 | nf_unregister_hooks(ipv6_conntrack_ops, ARRAY_SIZE(ipv6_conntrack_ops)); |
| 484 | nf_conntrack_l3proto_unregister(&nf_conntrack_l3proto_ipv6); |
| 485 | nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_icmpv6); |
| 486 | nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_udp6); |
| 487 | nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_tcp6); |
| 488 | nf_ct_frag6_cleanup(); |
| 489 | } |
| 490 | |
| 491 | module_init(nf_conntrack_l3proto_ipv6_init); |
| 492 | module_exit(nf_conntrack_l3proto_ipv6_fini); |