libnl  3.2.14
ct.c
1 /*
2  * lib/netfilter/ct.c Conntrack
3  *
4  * This library is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation version 2.1
7  * of the License.
8  *
9  * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
10  * Copyright (c) 2007 Philip Craig <philipc@snapgear.com>
11  * Copyright (c) 2007 Secure Computing Corporation
12  * Copyright (c= 2008 Patrick McHardy <kaber@trash.net>
13  */
14 
15 /**
16  * @ingroup nfnl
17  * @defgroup ct Conntrack
18  * @brief
19  * @{
20  */
21 
22 #include <byteswap.h>
23 #include <sys/types.h>
24 #include <linux/netfilter/nfnetlink_conntrack.h>
25 
26 #include <netlink-local.h>
27 #include <netlink/attr.h>
28 #include <netlink/netfilter/nfnl.h>
29 #include <netlink/netfilter/ct.h>
30 
31 static struct nl_cache_ops nfnl_ct_ops;
32 
33 #if __BYTE_ORDER == __BIG_ENDIAN
34 static uint64_t ntohll(uint64_t x)
35 {
36  return x;
37 }
38 #elif __BYTE_ORDER == __LITTLE_ENDIAN
39 static uint64_t ntohll(uint64_t x)
40 {
41  return bswap_64(x);
42 }
43 #endif
44 
45 static struct nla_policy ct_policy[CTA_MAX+1] = {
46  [CTA_TUPLE_ORIG] = { .type = NLA_NESTED },
47  [CTA_TUPLE_REPLY] = { .type = NLA_NESTED },
48  [CTA_STATUS] = { .type = NLA_U32 },
49  [CTA_PROTOINFO] = { .type = NLA_NESTED },
50  //[CTA_HELP]
51  //[CTA_NAT_SRC]
52  [CTA_TIMEOUT] = { .type = NLA_U32 },
53  [CTA_MARK] = { .type = NLA_U32 },
54  [CTA_COUNTERS_ORIG] = { .type = NLA_NESTED },
55  [CTA_COUNTERS_REPLY] = { .type = NLA_NESTED },
56  [CTA_USE] = { .type = NLA_U32 },
57  [CTA_ID] = { .type = NLA_U32 },
58  //[CTA_NAT_DST]
59 };
60 
61 static struct nla_policy ct_tuple_policy[CTA_TUPLE_MAX+1] = {
62  [CTA_TUPLE_IP] = { .type = NLA_NESTED },
63  [CTA_TUPLE_PROTO] = { .type = NLA_NESTED },
64 };
65 
66 static struct nla_policy ct_ip_policy[CTA_IP_MAX+1] = {
67  [CTA_IP_V4_SRC] = { .type = NLA_U32 },
68  [CTA_IP_V4_DST] = { .type = NLA_U32 },
69  [CTA_IP_V6_SRC] = { .minlen = 16 },
70  [CTA_IP_V6_DST] = { .minlen = 16 },
71 };
72 
73 static struct nla_policy ct_proto_policy[CTA_PROTO_MAX+1] = {
74  [CTA_PROTO_NUM] = { .type = NLA_U8 },
75  [CTA_PROTO_SRC_PORT] = { .type = NLA_U16 },
76  [CTA_PROTO_DST_PORT] = { .type = NLA_U16 },
77  [CTA_PROTO_ICMP_ID] = { .type = NLA_U16 },
78  [CTA_PROTO_ICMP_TYPE] = { .type = NLA_U8 },
79  [CTA_PROTO_ICMP_CODE] = { .type = NLA_U8 },
80  [CTA_PROTO_ICMPV6_ID] = { .type = NLA_U16 },
81  [CTA_PROTO_ICMPV6_TYPE] = { .type = NLA_U8 },
82  [CTA_PROTO_ICMPV6_CODE] = { .type = NLA_U8 },
83 };
84 
85 static struct nla_policy ct_protoinfo_policy[CTA_PROTOINFO_MAX+1] = {
86  [CTA_PROTOINFO_TCP] = { .type = NLA_NESTED },
87 };
88 
89 static struct nla_policy ct_protoinfo_tcp_policy[CTA_PROTOINFO_TCP_MAX+1] = {
90  [CTA_PROTOINFO_TCP_STATE] = { .type = NLA_U8 },
91  [CTA_PROTOINFO_TCP_WSCALE_ORIGINAL] = { .type = NLA_U8 },
92  [CTA_PROTOINFO_TCP_WSCALE_REPLY] = { .type = NLA_U8 },
93  [CTA_PROTOINFO_TCP_FLAGS_ORIGINAL] = { .minlen = 2 },
94  [CTA_PROTOINFO_TCP_FLAGS_REPLY] = { .minlen = 2 },
95 
96 };
97 
98 static struct nla_policy ct_counters_policy[CTA_COUNTERS_MAX+1] = {
99  [CTA_COUNTERS_PACKETS] = { .type = NLA_U64 },
100  [CTA_COUNTERS_BYTES] = { .type = NLA_U64 },
101  [CTA_COUNTERS32_PACKETS]= { .type = NLA_U32 },
102  [CTA_COUNTERS32_BYTES] = { .type = NLA_U32 },
103 };
104 
105 static int ct_parse_ip(struct nfnl_ct *ct, int repl, struct nlattr *attr)
106 {
107  struct nlattr *tb[CTA_IP_MAX+1];
108  struct nl_addr *addr;
109  int err;
110 
111  err = nla_parse_nested(tb, CTA_IP_MAX, attr, ct_ip_policy);
112  if (err < 0)
113  goto errout;
114 
115  if (tb[CTA_IP_V4_SRC]) {
116  addr = nl_addr_alloc_attr(tb[CTA_IP_V4_SRC], AF_INET);
117  if (addr == NULL)
118  goto errout_enomem;
119  err = nfnl_ct_set_src(ct, repl, addr);
120  nl_addr_put(addr);
121  if (err < 0)
122  goto errout;
123  }
124  if (tb[CTA_IP_V4_DST]) {
125  addr = nl_addr_alloc_attr(tb[CTA_IP_V4_DST], AF_INET);
126  if (addr == NULL)
127  goto errout_enomem;
128  err = nfnl_ct_set_dst(ct, repl, addr);
129  nl_addr_put(addr);
130  if (err < 0)
131  goto errout;
132  }
133  if (tb[CTA_IP_V6_SRC]) {
134  addr = nl_addr_alloc_attr(tb[CTA_IP_V6_SRC], AF_INET6);
135  if (addr == NULL)
136  goto errout_enomem;
137  err = nfnl_ct_set_src(ct, repl, addr);
138  nl_addr_put(addr);
139  if (err < 0)
140  goto errout;
141  }
142  if (tb[CTA_IP_V6_DST]) {
143  addr = nl_addr_alloc_attr(tb[CTA_IP_V6_DST], AF_INET6);
144  if (addr == NULL)
145  goto errout_enomem;
146  err = nfnl_ct_set_dst(ct, repl, addr);
147  nl_addr_put(addr);
148  if (err < 0)
149  goto errout;
150  }
151 
152  return 0;
153 
154 errout_enomem:
155  err = -NLE_NOMEM;
156 errout:
157  return err;
158 }
159 
160 static int ct_parse_proto(struct nfnl_ct *ct, int repl, struct nlattr *attr)
161 {
162  struct nlattr *tb[CTA_PROTO_MAX+1];
163  int err;
164 
165  err = nla_parse_nested(tb, CTA_PROTO_MAX, attr, ct_proto_policy);
166  if (err < 0)
167  return err;
168 
169  if (!repl && tb[CTA_PROTO_NUM])
170  nfnl_ct_set_proto(ct, nla_get_u8(tb[CTA_PROTO_NUM]));
171  if (tb[CTA_PROTO_SRC_PORT])
172  nfnl_ct_set_src_port(ct, repl,
173  ntohs(nla_get_u16(tb[CTA_PROTO_SRC_PORT])));
174  if (tb[CTA_PROTO_DST_PORT])
175  nfnl_ct_set_dst_port(ct, repl,
176  ntohs(nla_get_u16(tb[CTA_PROTO_DST_PORT])));
177  if (tb[CTA_PROTO_ICMP_ID])
178  nfnl_ct_set_icmp_id(ct, repl,
179  ntohs(nla_get_u16(tb[CTA_PROTO_ICMP_ID])));
180  if (tb[CTA_PROTO_ICMP_TYPE])
181  nfnl_ct_set_icmp_type(ct, repl,
182  nla_get_u8(tb[CTA_PROTO_ICMP_TYPE]));
183  if (tb[CTA_PROTO_ICMP_CODE])
184  nfnl_ct_set_icmp_code(ct, repl,
185  nla_get_u8(tb[CTA_PROTO_ICMP_CODE]));
186 
187  return 0;
188 }
189 
190 static int ct_parse_tuple(struct nfnl_ct *ct, int repl, struct nlattr *attr)
191 {
192  struct nlattr *tb[CTA_TUPLE_MAX+1];
193  int err;
194 
195  err = nla_parse_nested(tb, CTA_TUPLE_MAX, attr, ct_tuple_policy);
196  if (err < 0)
197  return err;
198 
199  if (tb[CTA_TUPLE_IP]) {
200  err = ct_parse_ip(ct, repl, tb[CTA_TUPLE_IP]);
201  if (err < 0)
202  return err;
203  }
204 
205  if (tb[CTA_TUPLE_PROTO]) {
206  err = ct_parse_proto(ct, repl, tb[CTA_TUPLE_PROTO]);
207  if (err < 0)
208  return err;
209  }
210 
211  return 0;
212 }
213 
214 static int ct_parse_protoinfo_tcp(struct nfnl_ct *ct, struct nlattr *attr)
215 {
216  struct nlattr *tb[CTA_PROTOINFO_TCP_MAX+1];
217  int err;
218 
219  err = nla_parse_nested(tb, CTA_PROTOINFO_TCP_MAX, attr,
220  ct_protoinfo_tcp_policy);
221  if (err < 0)
222  return err;
223 
224  if (tb[CTA_PROTOINFO_TCP_STATE])
225  nfnl_ct_set_tcp_state(ct,
226  nla_get_u8(tb[CTA_PROTOINFO_TCP_STATE]));
227 
228  return 0;
229 }
230 
231 static int ct_parse_protoinfo(struct nfnl_ct *ct, struct nlattr *attr)
232 {
233  struct nlattr *tb[CTA_PROTOINFO_MAX+1];
234  int err;
235 
236  err = nla_parse_nested(tb, CTA_PROTOINFO_MAX, attr,
237  ct_protoinfo_policy);
238  if (err < 0)
239  return err;
240 
241  if (tb[CTA_PROTOINFO_TCP]) {
242  err = ct_parse_protoinfo_tcp(ct, tb[CTA_PROTOINFO_TCP]);
243  if (err < 0)
244  return err;
245  }
246 
247  return 0;
248 }
249 
250 static int ct_parse_counters(struct nfnl_ct *ct, int repl, struct nlattr *attr)
251 {
252  struct nlattr *tb[CTA_COUNTERS_MAX+1];
253  int err;
254 
255  err = nla_parse_nested(tb, CTA_COUNTERS_MAX, attr, ct_counters_policy);
256  if (err < 0)
257  return err;
258 
259  if (tb[CTA_COUNTERS_PACKETS])
260  nfnl_ct_set_packets(ct, repl,
261  ntohll(nla_get_u64(tb[CTA_COUNTERS_PACKETS])));
262  if (tb[CTA_COUNTERS32_PACKETS])
263  nfnl_ct_set_packets(ct, repl,
264  ntohl(nla_get_u32(tb[CTA_COUNTERS32_PACKETS])));
265  if (tb[CTA_COUNTERS_BYTES])
266  nfnl_ct_set_bytes(ct, repl,
267  ntohll(nla_get_u64(tb[CTA_COUNTERS_BYTES])));
268  if (tb[CTA_COUNTERS32_BYTES])
269  nfnl_ct_set_bytes(ct, repl,
270  ntohl(nla_get_u32(tb[CTA_COUNTERS32_BYTES])));
271 
272  return 0;
273 }
274 
275 int nfnlmsg_ct_group(struct nlmsghdr *nlh)
276 {
277  switch (nfnlmsg_subtype(nlh)) {
278  case IPCTNL_MSG_CT_NEW:
279  if (nlh->nlmsg_flags & (NLM_F_CREATE|NLM_F_EXCL))
280  return NFNLGRP_CONNTRACK_NEW;
281  else
282  return NFNLGRP_CONNTRACK_UPDATE;
283  case IPCTNL_MSG_CT_DELETE:
284  return NFNLGRP_CONNTRACK_DESTROY;
285  default:
286  return NFNLGRP_NONE;
287  }
288 }
289 
290 int nfnlmsg_ct_parse(struct nlmsghdr *nlh, struct nfnl_ct **result)
291 {
292  struct nfnl_ct *ct;
293  struct nlattr *tb[CTA_MAX+1];
294  int err;
295 
296  ct = nfnl_ct_alloc();
297  if (!ct)
298  return -NLE_NOMEM;
299 
300  ct->ce_msgtype = nlh->nlmsg_type;
301 
302  err = nlmsg_parse(nlh, sizeof(struct nfgenmsg), tb, CTA_MAX,
303  ct_policy);
304  if (err < 0)
305  goto errout;
306 
307  nfnl_ct_set_family(ct, nfnlmsg_family(nlh));
308 
309  if (tb[CTA_TUPLE_ORIG]) {
310  err = ct_parse_tuple(ct, 0, tb[CTA_TUPLE_ORIG]);
311  if (err < 0)
312  goto errout;
313  }
314  if (tb[CTA_TUPLE_REPLY]) {
315  err = ct_parse_tuple(ct, 1, tb[CTA_TUPLE_REPLY]);
316  if (err < 0)
317  goto errout;
318  }
319 
320  if (tb[CTA_PROTOINFO]) {
321  err = ct_parse_protoinfo(ct, tb[CTA_PROTOINFO]);
322  if (err < 0)
323  goto errout;
324  }
325 
326  if (tb[CTA_STATUS])
327  nfnl_ct_set_status(ct, ntohl(nla_get_u32(tb[CTA_STATUS])));
328  if (tb[CTA_TIMEOUT])
329  nfnl_ct_set_timeout(ct, ntohl(nla_get_u32(tb[CTA_TIMEOUT])));
330  if (tb[CTA_MARK])
331  nfnl_ct_set_mark(ct, ntohl(nla_get_u32(tb[CTA_MARK])));
332  if (tb[CTA_USE])
333  nfnl_ct_set_use(ct, ntohl(nla_get_u32(tb[CTA_USE])));
334  if (tb[CTA_ID])
335  nfnl_ct_set_id(ct, ntohl(nla_get_u32(tb[CTA_ID])));
336 
337  if (tb[CTA_COUNTERS_ORIG]) {
338  err = ct_parse_counters(ct, 0, tb[CTA_COUNTERS_ORIG]);
339  if (err < 0)
340  goto errout;
341  }
342 
343  if (tb[CTA_COUNTERS_REPLY]) {
344  err = ct_parse_counters(ct, 1, tb[CTA_COUNTERS_REPLY]);
345  if (err < 0)
346  goto errout;
347  }
348 
349  *result = ct;
350  return 0;
351 
352 errout:
353  nfnl_ct_put(ct);
354  return err;
355 }
356 
357 static int ct_msg_parser(struct nl_cache_ops *ops, struct sockaddr_nl *who,
358  struct nlmsghdr *nlh, struct nl_parser_param *pp)
359 {
360  struct nfnl_ct *ct;
361  int err;
362 
363  if ((err = nfnlmsg_ct_parse(nlh, &ct)) < 0)
364  goto errout;
365 
366  err = pp->pp_cb((struct nl_object *) ct, pp);
367 errout:
368  nfnl_ct_put(ct);
369  return err;
370 }
371 
372 int nfnl_ct_dump_request(struct nl_sock *sk)
373 {
374  return nfnl_send_simple(sk, NFNL_SUBSYS_CTNETLINK, IPCTNL_MSG_CT_GET,
375  NLM_F_DUMP, AF_UNSPEC, 0);
376 }
377 
378 static int ct_request_update(struct nl_cache *cache, struct nl_sock *sk)
379 {
380  return nfnl_ct_dump_request(sk);
381 }
382 
383 static int nfnl_ct_build_tuple(struct nl_msg *msg, const struct nfnl_ct *ct,
384  int repl)
385 {
386  struct nlattr *tuple, *ip, *proto;
387  struct nl_addr *addr;
388  int family;
389 
390  family = nfnl_ct_get_family(ct);
391 
392  tuple = nla_nest_start(msg, repl ? CTA_TUPLE_REPLY : CTA_TUPLE_ORIG);
393  if (!tuple)
394  goto nla_put_failure;
395 
396  ip = nla_nest_start(msg, CTA_TUPLE_IP);
397  if (!ip)
398  goto nla_put_failure;
399 
400  addr = nfnl_ct_get_src(ct, repl);
401  if (addr)
402  NLA_PUT_ADDR(msg,
403  family == AF_INET ? CTA_IP_V4_SRC : CTA_IP_V6_SRC,
404  addr);
405 
406  addr = nfnl_ct_get_dst(ct, repl);
407  if (addr)
408  NLA_PUT_ADDR(msg,
409  family == AF_INET ? CTA_IP_V4_DST : CTA_IP_V6_DST,
410  addr);
411 
412  nla_nest_end(msg, ip);
413 
414  proto = nla_nest_start(msg, CTA_TUPLE_PROTO);
415  if (!proto)
416  goto nla_put_failure;
417 
418  if (nfnl_ct_test_proto(ct))
419  NLA_PUT_U8(msg, CTA_PROTO_NUM, nfnl_ct_get_proto(ct));
420 
421  if (nfnl_ct_test_src_port(ct, repl))
422  NLA_PUT_U16(msg, CTA_PROTO_SRC_PORT,
423  htons(nfnl_ct_get_src_port(ct, repl)));
424 
425  if (nfnl_ct_test_dst_port(ct, repl))
426  NLA_PUT_U16(msg, CTA_PROTO_DST_PORT,
427  htons(nfnl_ct_get_dst_port(ct, repl)));
428 
429  if (nfnl_ct_test_icmp_id(ct, repl))
430  NLA_PUT_U16(msg, CTA_PROTO_ICMP_ID,
431  htons(nfnl_ct_get_icmp_id(ct, repl)));
432 
433  if (nfnl_ct_test_icmp_type(ct, repl))
434  NLA_PUT_U8(msg, CTA_PROTO_ICMP_TYPE,
435  nfnl_ct_get_icmp_type(ct, repl));
436 
437  if (nfnl_ct_test_icmp_code(ct, repl))
438  NLA_PUT_U8(msg, CTA_PROTO_ICMP_CODE,
439  nfnl_ct_get_icmp_code(ct, repl));
440 
441  nla_nest_end(msg, proto);
442 
443  nla_nest_end(msg, tuple);
444  return 0;
445 
446 nla_put_failure:
447  return -NLE_MSGSIZE;
448 }
449 
450 static int nfnl_ct_build_message(const struct nfnl_ct *ct, int cmd, int flags,
451  struct nl_msg **result)
452 {
453  struct nl_msg *msg;
454  int err;
455 
456  msg = nfnlmsg_alloc_simple(NFNL_SUBSYS_CTNETLINK, cmd, flags,
457  nfnl_ct_get_family(ct), 0);
458  if (msg == NULL)
459  return -NLE_NOMEM;
460 
461  if ((err = nfnl_ct_build_tuple(msg, ct, 0)) < 0)
462  goto err_out;
463 
464  *result = msg;
465  return 0;
466 
467 err_out:
468  nlmsg_free(msg);
469  return err;
470 }
471 
472 int nfnl_ct_build_add_request(const struct nfnl_ct *ct, int flags,
473  struct nl_msg **result)
474 {
475  return nfnl_ct_build_message(ct, IPCTNL_MSG_CT_NEW, flags, result);
476 }
477 
478 int nfnl_ct_add(struct nl_sock *sk, const struct nfnl_ct *ct, int flags)
479 {
480  struct nl_msg *msg;
481  int err;
482 
483  if ((err = nfnl_ct_build_add_request(ct, flags, &msg)) < 0)
484  return err;
485 
486  err = nl_send_auto_complete(sk, msg);
487  nlmsg_free(msg);
488  if (err < 0)
489  return err;
490 
491  return wait_for_ack(sk);
492 }
493 
494 int nfnl_ct_build_delete_request(const struct nfnl_ct *ct, int flags,
495  struct nl_msg **result)
496 {
497  return nfnl_ct_build_message(ct, IPCTNL_MSG_CT_DELETE, flags, result);
498 }
499 
500 int nfnl_ct_del(struct nl_sock *sk, const struct nfnl_ct *ct, int flags)
501 {
502  struct nl_msg *msg;
503  int err;
504 
505  if ((err = nfnl_ct_build_delete_request(ct, flags, &msg)) < 0)
506  return err;
507 
508  err = nl_send_auto_complete(sk, msg);
509  nlmsg_free(msg);
510  if (err < 0)
511  return err;
512 
513  return wait_for_ack(sk);
514 }
515 
516 int nfnl_ct_build_query_request(const struct nfnl_ct *ct, int flags,
517  struct nl_msg **result)
518 {
519  return nfnl_ct_build_message(ct, IPCTNL_MSG_CT_GET, flags, result);
520 }
521 
522 int nfnl_ct_query(struct nl_sock *sk, const struct nfnl_ct *ct, int flags)
523 {
524  struct nl_msg *msg;
525  int err;
526 
527  if ((err = nfnl_ct_build_query_request(ct, flags, &msg)) < 0)
528  return err;
529 
530  err = nl_send_auto_complete(sk, msg);
531  nlmsg_free(msg);
532  if (err < 0)
533  return err;
534 
535  return wait_for_ack(sk);
536 }
537 
538 /**
539  * @name Cache Management
540  * @{
541  */
542 
543 /**
544  * Build a conntrack cache holding all conntrack currently in the kernel
545  * @arg sk Netlink socket.
546  * @arg result Pointer to store resulting cache.
547  *
548  * Allocates a new cache, initializes it properly and updates it to
549  * contain all conntracks currently in the kernel.
550  *
551  * @return 0 on success or a negative error code.
552  */
553 int nfnl_ct_alloc_cache(struct nl_sock *sk, struct nl_cache **result)
554 {
555  return nl_cache_alloc_and_fill(&nfnl_ct_ops, sk, result);
556 }
557 
558 /** @} */
559 
560 /**
561  * @name Conntrack Addition
562  * @{
563  */
564 
565 /** @} */
566 
567 static struct nl_af_group ct_groups[] = {
568  { AF_UNSPEC, NFNLGRP_CONNTRACK_NEW },
569  { AF_UNSPEC, NFNLGRP_CONNTRACK_UPDATE },
570  { AF_UNSPEC, NFNLGRP_CONNTRACK_DESTROY },
571  { END_OF_GROUP_LIST },
572 };
573 
574 #define NFNLMSG_CT_TYPE(type) NFNLMSG_TYPE(NFNL_SUBSYS_CTNETLINK, (type))
575 static struct nl_cache_ops nfnl_ct_ops = {
576  .co_name = "netfilter/ct",
577  .co_hdrsize = NFNL_HDRLEN,
578  .co_msgtypes = {
579  { NFNLMSG_CT_TYPE(IPCTNL_MSG_CT_NEW), NL_ACT_NEW, "new" },
580  { NFNLMSG_CT_TYPE(IPCTNL_MSG_CT_GET), NL_ACT_GET, "get" },
581  { NFNLMSG_CT_TYPE(IPCTNL_MSG_CT_DELETE), NL_ACT_DEL, "del" },
582  END_OF_MSGTYPES_LIST,
583  },
584  .co_protocol = NETLINK_NETFILTER,
585  .co_groups = ct_groups,
586  .co_request_update = ct_request_update,
587  .co_msg_parser = ct_msg_parser,
588  .co_obj_ops = &ct_obj_ops,
589 };
590 
591 static void __init ct_init(void)
592 {
593  nl_cache_mngt_register(&nfnl_ct_ops);
594 }
595 
596 static void __exit ct_exit(void)
597 {
598  nl_cache_mngt_unregister(&nfnl_ct_ops);
599 }
600 
601 /** @} */