libnftnl  1.2.2
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, sizeof(log->group));
50  break;
51  case NFTNL_EXPR_LOG_SNAPLEN:
52  memcpy(&log->snaplen, data, sizeof(log->snaplen));
53  break;
54  case NFTNL_EXPR_LOG_QTHRESHOLD:
55  memcpy(&log->qthreshold, data, sizeof(log->qthreshold));
56  break;
57  case NFTNL_EXPR_LOG_LEVEL:
58  memcpy(&log->level, data, sizeof(log->level));
59  break;
60  case NFTNL_EXPR_LOG_FLAGS:
61  memcpy(&log->flags, data, sizeof(log->flags));
62  break;
63  default:
64  return -1;
65  }
66  return 0;
67 }
68 
69 static const void *
70 nftnl_expr_log_get(const struct nftnl_expr *e, uint16_t type,
71  uint32_t *data_len)
72 {
73  struct nftnl_expr_log *log = nftnl_expr_data(e);
74 
75  switch(type) {
76  case NFTNL_EXPR_LOG_PREFIX:
77  *data_len = strlen(log->prefix)+1;
78  return log->prefix;
79  case NFTNL_EXPR_LOG_GROUP:
80  *data_len = sizeof(log->group);
81  return &log->group;
82  case NFTNL_EXPR_LOG_SNAPLEN:
83  *data_len = sizeof(log->snaplen);
84  return &log->snaplen;
85  case NFTNL_EXPR_LOG_QTHRESHOLD:
86  *data_len = sizeof(log->qthreshold);
87  return &log->qthreshold;
88  case NFTNL_EXPR_LOG_LEVEL:
89  *data_len = sizeof(log->level);
90  return &log->level;
91  case NFTNL_EXPR_LOG_FLAGS:
92  *data_len = sizeof(log->flags);
93  return &log->flags;
94  }
95  return NULL;
96 }
97 
98 static int nftnl_expr_log_cb(const struct nlattr *attr, void *data)
99 {
100  const struct nlattr **tb = data;
101  int type = mnl_attr_get_type(attr);
102 
103  if (mnl_attr_type_valid(attr, NFTA_LOG_MAX) < 0)
104  return MNL_CB_OK;
105 
106  switch(type) {
107  case NFTA_LOG_PREFIX:
108  if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
109  abi_breakage();
110  break;
111  case NFTA_LOG_GROUP:
112  case NFTA_LOG_QTHRESHOLD:
113  if (mnl_attr_validate(attr, MNL_TYPE_U16) < 0)
114  abi_breakage();
115  break;
116  case NFTA_LOG_SNAPLEN:
117  case NFTA_LOG_LEVEL:
118  case NFTA_LOG_FLAGS:
119  if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
120  abi_breakage();
121  break;
122  }
123 
124  tb[type] = attr;
125  return MNL_CB_OK;
126 }
127 
128 static void
129 nftnl_expr_log_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
130 {
131  struct nftnl_expr_log *log = nftnl_expr_data(e);
132 
133  if (e->flags & (1 << NFTNL_EXPR_LOG_PREFIX))
134  mnl_attr_put_strz(nlh, NFTA_LOG_PREFIX, log->prefix);
135  if (e->flags & (1 << NFTNL_EXPR_LOG_GROUP))
136  mnl_attr_put_u16(nlh, NFTA_LOG_GROUP, htons(log->group));
137  if (e->flags & (1 << NFTNL_EXPR_LOG_SNAPLEN))
138  mnl_attr_put_u32(nlh, NFTA_LOG_SNAPLEN, htonl(log->snaplen));
139  if (e->flags & (1 << NFTNL_EXPR_LOG_QTHRESHOLD))
140  mnl_attr_put_u16(nlh, NFTA_LOG_QTHRESHOLD, htons(log->qthreshold));
141  if (e->flags & (1 << NFTNL_EXPR_LOG_LEVEL))
142  mnl_attr_put_u32(nlh, NFTA_LOG_LEVEL, htonl(log->level));
143  if (e->flags & (1 << NFTNL_EXPR_LOG_FLAGS))
144  mnl_attr_put_u32(nlh, NFTA_LOG_FLAGS, htonl(log->flags));
145 }
146 
147 static int
148 nftnl_expr_log_parse(struct nftnl_expr *e, struct nlattr *attr)
149 {
150  struct nftnl_expr_log *log = nftnl_expr_data(e);
151  struct nlattr *tb[NFTA_LOG_MAX+1] = {};
152 
153  if (mnl_attr_parse_nested(attr, nftnl_expr_log_cb, tb) < 0)
154  return -1;
155 
156  if (tb[NFTA_LOG_PREFIX]) {
157  if (log->prefix)
158  xfree(log->prefix);
159 
160  log->prefix = strdup(mnl_attr_get_str(tb[NFTA_LOG_PREFIX]));
161  if (!log->prefix)
162  return -1;
163  e->flags |= (1 << NFTNL_EXPR_LOG_PREFIX);
164  }
165  if (tb[NFTA_LOG_GROUP]) {
166  log->group = ntohs(mnl_attr_get_u16(tb[NFTA_LOG_GROUP]));
167  e->flags |= (1 << NFTNL_EXPR_LOG_GROUP);
168  }
169  if (tb[NFTA_LOG_SNAPLEN]) {
170  log->snaplen = ntohl(mnl_attr_get_u32(tb[NFTA_LOG_SNAPLEN]));
171  e->flags |= (1 << NFTNL_EXPR_LOG_SNAPLEN);
172  }
173  if (tb[NFTA_LOG_QTHRESHOLD]) {
174  log->qthreshold = ntohs(mnl_attr_get_u16(tb[NFTA_LOG_QTHRESHOLD]));
175  e->flags |= (1 << NFTNL_EXPR_LOG_QTHRESHOLD);
176  }
177  if (tb[NFTA_LOG_LEVEL]) {
178  log->level = ntohl(mnl_attr_get_u32(tb[NFTA_LOG_LEVEL]));
179  e->flags |= (1 << NFTNL_EXPR_LOG_LEVEL);
180  }
181  if (tb[NFTA_LOG_FLAGS]) {
182  log->flags = ntohl(mnl_attr_get_u32(tb[NFTA_LOG_FLAGS]));
183  e->flags |= (1 << NFTNL_EXPR_LOG_FLAGS);
184  }
185 
186  return 0;
187 }
188 
189 static int
190 nftnl_expr_log_snprintf(char *buf, size_t remain,
191  uint32_t flags, const struct nftnl_expr *e)
192 {
193  struct nftnl_expr_log *log = nftnl_expr_data(e);
194  int ret, offset = 0;
195 
196  if (e->flags & (1 << NFTNL_EXPR_LOG_PREFIX)) {
197  ret = snprintf(buf, remain, "prefix %s ", log->prefix);
198  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
199  }
200 
201  if (e->flags & (1 << NFTNL_EXPR_LOG_GROUP)) {
202  ret = snprintf(buf + offset, remain,
203  "group %u snaplen %u qthreshold %u ",
204  log->group, log->snaplen, log->qthreshold);
205  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
206  } else {
207  if (e->flags & (1 << NFTNL_EXPR_LOG_LEVEL)) {
208  ret = snprintf(buf + offset, remain, "level %u ",
209  log->level);
210  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
211  }
212  if (e->flags & (1 << NFTNL_EXPR_LOG_FLAGS)) {
213  if (log->flags & NF_LOG_TCPSEQ) {
214  ret = snprintf(buf + offset, remain, "tcpseq ");
215  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
216  }
217  if (log->flags & NF_LOG_TCPOPT) {
218  ret = snprintf(buf + offset, remain, "tcpopt ");
219  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
220  }
221  if (log->flags & NF_LOG_IPOPT) {
222  ret = snprintf(buf + offset, remain, "ipopt ");
223  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
224  }
225  if (log->flags & NF_LOG_UID) {
226  ret = snprintf(buf + offset, remain, "uid ");
227  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
228  }
229  if (log->flags & NF_LOG_MACDECODE) {
230  ret = snprintf(buf + offset, remain,
231  "macdecode ");
232  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
233  }
234  }
235  }
236 
237  return offset;
238 }
239 
240 static void nftnl_expr_log_free(const struct nftnl_expr *e)
241 {
242  struct nftnl_expr_log *log = nftnl_expr_data(e);
243 
244  xfree(log->prefix);
245 }
246 
247 struct expr_ops expr_ops_log = {
248  .name = "log",
249  .alloc_len = sizeof(struct nftnl_expr_log),
250  .max_attr = NFTA_LOG_MAX,
251  .free = nftnl_expr_log_free,
252  .set = nftnl_expr_log_set,
253  .get = nftnl_expr_log_get,
254  .parse = nftnl_expr_log_parse,
255  .build = nftnl_expr_log_build,
256  .snprintf = nftnl_expr_log_snprintf,
257 };