libnftnl  1.2.8
log.c
1 /*
2  * (C) 2012-2013 by Pablo Neira Ayuso <pablo@netfilter.org>
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 as published
6  * by the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This code has been sponsored by Sophos Astaro <http://www.sophos.com>
10  */
11 
12 #include <stdio.h>
13 #include <stdint.h>
14 #include <string.h>
15 #include <arpa/inet.h>
16 #include <errno.h>
17 #include <linux/netfilter/nf_tables.h>
18 #include <linux/netfilter/nf_log.h>
19 
20 #include "internal.h"
21 #include <libmnl/libmnl.h>
22 #include <libnftnl/expr.h>
23 #include <libnftnl/rule.h>
24 
26  uint32_t snaplen;
27  uint16_t group;
28  uint16_t qthreshold;
29  uint32_t level;
30  uint32_t flags;
31  const char *prefix;
32 };
33 
34 static int nftnl_expr_log_set(struct nftnl_expr *e, uint16_t type,
35  const void *data, uint32_t data_len)
36 {
37  struct nftnl_expr_log *log = nftnl_expr_data(e);
38 
39  switch(type) {
40  case NFTNL_EXPR_LOG_PREFIX:
41  if (log->flags & (1 << NFTNL_EXPR_LOG_PREFIX))
42  xfree(log->prefix);
43 
44  log->prefix = strdup(data);
45  if (!log->prefix)
46  return -1;
47  break;
48  case NFTNL_EXPR_LOG_GROUP:
49  memcpy(&log->group, data, data_len);
50  break;
51  case NFTNL_EXPR_LOG_SNAPLEN:
52  memcpy(&log->snaplen, data, data_len);
53  break;
54  case NFTNL_EXPR_LOG_QTHRESHOLD:
55  memcpy(&log->qthreshold, data, data_len);
56  break;
57  case NFTNL_EXPR_LOG_LEVEL:
58  memcpy(&log->level, data, data_len);
59  break;
60  case NFTNL_EXPR_LOG_FLAGS:
61  memcpy(&log->flags, data, data_len);
62  break;
63  }
64  return 0;
65 }
66 
67 static const void *
68 nftnl_expr_log_get(const struct nftnl_expr *e, uint16_t type,
69  uint32_t *data_len)
70 {
71  struct nftnl_expr_log *log = nftnl_expr_data(e);
72 
73  switch(type) {
74  case NFTNL_EXPR_LOG_PREFIX:
75  *data_len = strlen(log->prefix)+1;
76  return log->prefix;
77  case NFTNL_EXPR_LOG_GROUP:
78  *data_len = sizeof(log->group);
79  return &log->group;
80  case NFTNL_EXPR_LOG_SNAPLEN:
81  *data_len = sizeof(log->snaplen);
82  return &log->snaplen;
83  case NFTNL_EXPR_LOG_QTHRESHOLD:
84  *data_len = sizeof(log->qthreshold);
85  return &log->qthreshold;
86  case NFTNL_EXPR_LOG_LEVEL:
87  *data_len = sizeof(log->level);
88  return &log->level;
89  case NFTNL_EXPR_LOG_FLAGS:
90  *data_len = sizeof(log->flags);
91  return &log->flags;
92  }
93  return NULL;
94 }
95 
96 static int nftnl_expr_log_cb(const struct nlattr *attr, void *data)
97 {
98  const struct nlattr **tb = data;
99  int type = mnl_attr_get_type(attr);
100 
101  if (mnl_attr_type_valid(attr, NFTA_LOG_MAX) < 0)
102  return MNL_CB_OK;
103 
104  switch(type) {
105  case NFTA_LOG_PREFIX:
106  if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
107  abi_breakage();
108  break;
109  case NFTA_LOG_GROUP:
110  case NFTA_LOG_QTHRESHOLD:
111  if (mnl_attr_validate(attr, MNL_TYPE_U16) < 0)
112  abi_breakage();
113  break;
114  case NFTA_LOG_SNAPLEN:
115  case NFTA_LOG_LEVEL:
116  case NFTA_LOG_FLAGS:
117  if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
118  abi_breakage();
119  break;
120  }
121 
122  tb[type] = attr;
123  return MNL_CB_OK;
124 }
125 
126 static void
127 nftnl_expr_log_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
128 {
129  struct nftnl_expr_log *log = nftnl_expr_data(e);
130 
131  if (e->flags & (1 << NFTNL_EXPR_LOG_PREFIX))
132  mnl_attr_put_strz(nlh, NFTA_LOG_PREFIX, log->prefix);
133  if (e->flags & (1 << NFTNL_EXPR_LOG_GROUP))
134  mnl_attr_put_u16(nlh, NFTA_LOG_GROUP, htons(log->group));
135  if (e->flags & (1 << NFTNL_EXPR_LOG_SNAPLEN))
136  mnl_attr_put_u32(nlh, NFTA_LOG_SNAPLEN, htonl(log->snaplen));
137  if (e->flags & (1 << NFTNL_EXPR_LOG_QTHRESHOLD))
138  mnl_attr_put_u16(nlh, NFTA_LOG_QTHRESHOLD, htons(log->qthreshold));
139  if (e->flags & (1 << NFTNL_EXPR_LOG_LEVEL))
140  mnl_attr_put_u32(nlh, NFTA_LOG_LEVEL, htonl(log->level));
141  if (e->flags & (1 << NFTNL_EXPR_LOG_FLAGS))
142  mnl_attr_put_u32(nlh, NFTA_LOG_FLAGS, htonl(log->flags));
143 }
144 
145 static int
146 nftnl_expr_log_parse(struct nftnl_expr *e, struct nlattr *attr)
147 {
148  struct nftnl_expr_log *log = nftnl_expr_data(e);
149  struct nlattr *tb[NFTA_LOG_MAX+1] = {};
150 
151  if (mnl_attr_parse_nested(attr, nftnl_expr_log_cb, tb) < 0)
152  return -1;
153 
154  if (tb[NFTA_LOG_PREFIX]) {
155  if (log->prefix)
156  xfree(log->prefix);
157 
158  log->prefix = strdup(mnl_attr_get_str(tb[NFTA_LOG_PREFIX]));
159  if (!log->prefix)
160  return -1;
161  e->flags |= (1 << NFTNL_EXPR_LOG_PREFIX);
162  }
163  if (tb[NFTA_LOG_GROUP]) {
164  log->group = ntohs(mnl_attr_get_u16(tb[NFTA_LOG_GROUP]));
165  e->flags |= (1 << NFTNL_EXPR_LOG_GROUP);
166  }
167  if (tb[NFTA_LOG_SNAPLEN]) {
168  log->snaplen = ntohl(mnl_attr_get_u32(tb[NFTA_LOG_SNAPLEN]));
169  e->flags |= (1 << NFTNL_EXPR_LOG_SNAPLEN);
170  }
171  if (tb[NFTA_LOG_QTHRESHOLD]) {
172  log->qthreshold = ntohs(mnl_attr_get_u16(tb[NFTA_LOG_QTHRESHOLD]));
173  e->flags |= (1 << NFTNL_EXPR_LOG_QTHRESHOLD);
174  }
175  if (tb[NFTA_LOG_LEVEL]) {
176  log->level = ntohl(mnl_attr_get_u32(tb[NFTA_LOG_LEVEL]));
177  e->flags |= (1 << NFTNL_EXPR_LOG_LEVEL);
178  }
179  if (tb[NFTA_LOG_FLAGS]) {
180  log->flags = ntohl(mnl_attr_get_u32(tb[NFTA_LOG_FLAGS]));
181  e->flags |= (1 << NFTNL_EXPR_LOG_FLAGS);
182  }
183 
184  return 0;
185 }
186 
187 static int
188 nftnl_expr_log_snprintf(char *buf, size_t remain,
189  uint32_t flags, const struct nftnl_expr *e)
190 {
191  struct nftnl_expr_log *log = nftnl_expr_data(e);
192  int ret, offset = 0;
193 
194  if (e->flags & (1 << NFTNL_EXPR_LOG_PREFIX)) {
195  ret = snprintf(buf, remain, "prefix %s ", log->prefix);
196  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
197  }
198 
199  if (e->flags & (1 << NFTNL_EXPR_LOG_GROUP)) {
200  ret = snprintf(buf + offset, remain,
201  "group %u snaplen %u qthreshold %u ",
202  log->group, log->snaplen, log->qthreshold);
203  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
204  } else {
205  if (e->flags & (1 << NFTNL_EXPR_LOG_LEVEL)) {
206  ret = snprintf(buf + offset, remain, "level %u ",
207  log->level);
208  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
209  }
210  if (e->flags & (1 << NFTNL_EXPR_LOG_FLAGS)) {
211  if (log->flags & NF_LOG_TCPSEQ) {
212  ret = snprintf(buf + offset, remain, "tcpseq ");
213  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
214  }
215  if (log->flags & NF_LOG_TCPOPT) {
216  ret = snprintf(buf + offset, remain, "tcpopt ");
217  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
218  }
219  if (log->flags & NF_LOG_IPOPT) {
220  ret = snprintf(buf + offset, remain, "ipopt ");
221  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
222  }
223  if (log->flags & NF_LOG_UID) {
224  ret = snprintf(buf + offset, remain, "uid ");
225  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
226  }
227  if (log->flags & NF_LOG_MACDECODE) {
228  ret = snprintf(buf + offset, remain,
229  "macdecode ");
230  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
231  }
232  }
233  }
234 
235  return offset;
236 }
237 
238 static void nftnl_expr_log_free(const struct nftnl_expr *e)
239 {
240  struct nftnl_expr_log *log = nftnl_expr_data(e);
241 
242  xfree(log->prefix);
243 }
244 
245 static struct attr_policy log_attr_policy[__NFTNL_EXPR_LOG_MAX] = {
246  [NFTNL_EXPR_LOG_PREFIX] = { .maxlen = NF_LOG_PREFIXLEN },
247  [NFTNL_EXPR_LOG_GROUP] = { .maxlen = sizeof(uint16_t) },
248  [NFTNL_EXPR_LOG_SNAPLEN] = { .maxlen = sizeof(uint32_t) },
249  [NFTNL_EXPR_LOG_QTHRESHOLD] = { .maxlen = sizeof(uint16_t) },
250  [NFTNL_EXPR_LOG_LEVEL] = { .maxlen = sizeof(uint32_t) },
251  [NFTNL_EXPR_LOG_FLAGS] = { .maxlen = sizeof(uint32_t) },
252 };
253 
254 struct expr_ops expr_ops_log = {
255  .name = "log",
256  .alloc_len = sizeof(struct nftnl_expr_log),
257  .nftnl_max_attr = __NFTNL_EXPR_LOG_MAX - 1,
258  .attr_policy = log_attr_policy,
259  .free = nftnl_expr_log_free,
260  .set = nftnl_expr_log_set,
261  .get = nftnl_expr_log_get,
262  .parse = nftnl_expr_log_parse,
263  .build = nftnl_expr_log_build,
264  .output = nftnl_expr_log_snprintf,
265 };