libnftnl  1.3.2
log.c
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * (C) 2012-2013 by Pablo Neira Ayuso <pablo@netfilter.org>
4  *
5  * This code has been sponsored by Sophos Astaro <http://www.sophos.com>
6  */
7 
8 #include <stdio.h>
9 #include <stdint.h>
10 #include <string.h>
11 #include <arpa/inet.h>
12 #include <errno.h>
13 #include <linux/netfilter/nf_tables.h>
14 #include <linux/netfilter/nf_log.h>
15 
16 #include "internal.h"
17 #include <libmnl/libmnl.h>
18 #include <libnftnl/expr.h>
19 #include <libnftnl/rule.h>
20 
21 struct nftnl_expr_log {
22  uint32_t snaplen;
23  uint16_t group;
24  uint16_t qthreshold;
25  uint32_t level;
26  uint32_t flags;
27  const char *prefix;
28 };
29 
30 static int
31 nftnl_expr_log_set(struct nftnl_expr *e, uint16_t type,
32  const void *data, uint32_t data_len, uint32_t byteorder)
33 {
34  struct nftnl_expr_log *log = nftnl_expr_data(e);
35 
36  switch(type) {
37  case NFTNL_EXPR_LOG_PREFIX:
38  if (log->flags & (1 << NFTNL_EXPR_LOG_PREFIX))
39  xfree(log->prefix);
40 
41  log->prefix = strdup(data);
42  if (!log->prefix)
43  return -1;
44  break;
45  case NFTNL_EXPR_LOG_GROUP:
46  memcpy(&log->group, data, data_len);
47  break;
48  case NFTNL_EXPR_LOG_SNAPLEN:
49  memcpy(&log->snaplen, data, data_len);
50  break;
51  case NFTNL_EXPR_LOG_QTHRESHOLD:
52  memcpy(&log->qthreshold, data, data_len);
53  break;
54  case NFTNL_EXPR_LOG_LEVEL:
55  memcpy(&log->level, data, data_len);
56  break;
57  case NFTNL_EXPR_LOG_FLAGS:
58  memcpy(&log->flags, data, data_len);
59  break;
60  }
61  return 0;
62 }
63 
64 static const void *
65 nftnl_expr_log_get(const struct nftnl_expr *e, uint16_t type,
66  uint32_t *data_len)
67 {
68  struct nftnl_expr_log *log = nftnl_expr_data(e);
69 
70  switch(type) {
71  case NFTNL_EXPR_LOG_PREFIX:
72  *data_len = strlen(log->prefix)+1;
73  return log->prefix;
74  case NFTNL_EXPR_LOG_GROUP:
75  *data_len = sizeof(log->group);
76  return &log->group;
77  case NFTNL_EXPR_LOG_SNAPLEN:
78  *data_len = sizeof(log->snaplen);
79  return &log->snaplen;
80  case NFTNL_EXPR_LOG_QTHRESHOLD:
81  *data_len = sizeof(log->qthreshold);
82  return &log->qthreshold;
83  case NFTNL_EXPR_LOG_LEVEL:
84  *data_len = sizeof(log->level);
85  return &log->level;
86  case NFTNL_EXPR_LOG_FLAGS:
87  *data_len = sizeof(log->flags);
88  return &log->flags;
89  }
90  return NULL;
91 }
92 
93 static int nftnl_expr_log_cb(const struct nlattr *attr, void *data)
94 {
95  const struct nlattr **tb = data;
96  int type = mnl_attr_get_type(attr);
97 
98  if (mnl_attr_type_valid(attr, NFTA_LOG_MAX) < 0)
99  return MNL_CB_OK;
100 
101  switch(type) {
102  case NFTA_LOG_PREFIX:
103  if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
104  abi_breakage();
105  break;
106  case NFTA_LOG_GROUP:
107  case NFTA_LOG_QTHRESHOLD:
108  if (mnl_attr_validate(attr, MNL_TYPE_U16) < 0)
109  abi_breakage();
110  break;
111  case NFTA_LOG_SNAPLEN:
112  case NFTA_LOG_LEVEL:
113  case NFTA_LOG_FLAGS:
114  if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
115  abi_breakage();
116  break;
117  }
118 
119  tb[type] = attr;
120  return MNL_CB_OK;
121 }
122 
123 static void
124 nftnl_expr_log_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
125 {
126  struct nftnl_expr_log *log = nftnl_expr_data(e);
127 
128  if (e->flags & (1 << NFTNL_EXPR_LOG_PREFIX))
129  mnl_attr_put_strz(nlh, NFTA_LOG_PREFIX, log->prefix);
130  if (e->flags & (1 << NFTNL_EXPR_LOG_GROUP))
131  mnl_attr_put_u16(nlh, NFTA_LOG_GROUP, htons(log->group));
132  if (e->flags & (1 << NFTNL_EXPR_LOG_SNAPLEN))
133  mnl_attr_put_u32(nlh, NFTA_LOG_SNAPLEN, htonl(log->snaplen));
134  if (e->flags & (1 << NFTNL_EXPR_LOG_QTHRESHOLD))
135  mnl_attr_put_u16(nlh, NFTA_LOG_QTHRESHOLD, htons(log->qthreshold));
136  if (e->flags & (1 << NFTNL_EXPR_LOG_LEVEL))
137  mnl_attr_put_u32(nlh, NFTA_LOG_LEVEL, htonl(log->level));
138  if (e->flags & (1 << NFTNL_EXPR_LOG_FLAGS))
139  mnl_attr_put_u32(nlh, NFTA_LOG_FLAGS, htonl(log->flags));
140 }
141 
142 static int
143 nftnl_expr_log_parse(struct nftnl_expr *e, struct nlattr *attr)
144 {
145  struct nftnl_expr_log *log = nftnl_expr_data(e);
146  struct nlattr *tb[NFTA_LOG_MAX+1] = {};
147 
148  if (mnl_attr_parse_nested(attr, nftnl_expr_log_cb, tb) < 0)
149  return -1;
150 
151  if (nftnl_parse_str_attr(tb[NFTA_LOG_PREFIX],
152  NFTNL_EXPR_LOG_PREFIX,
153  &log->prefix, &e->flags) < 0)
154  return -1;
155  if (tb[NFTA_LOG_GROUP]) {
156  log->group = ntohs(mnl_attr_get_u16(tb[NFTA_LOG_GROUP]));
157  e->flags |= (1 << NFTNL_EXPR_LOG_GROUP);
158  }
159  if (tb[NFTA_LOG_SNAPLEN]) {
160  log->snaplen = ntohl(mnl_attr_get_u32(tb[NFTA_LOG_SNAPLEN]));
161  e->flags |= (1 << NFTNL_EXPR_LOG_SNAPLEN);
162  }
163  if (tb[NFTA_LOG_QTHRESHOLD]) {
164  log->qthreshold = ntohs(mnl_attr_get_u16(tb[NFTA_LOG_QTHRESHOLD]));
165  e->flags |= (1 << NFTNL_EXPR_LOG_QTHRESHOLD);
166  }
167  if (tb[NFTA_LOG_LEVEL]) {
168  log->level = ntohl(mnl_attr_get_u32(tb[NFTA_LOG_LEVEL]));
169  e->flags |= (1 << NFTNL_EXPR_LOG_LEVEL);
170  }
171  if (tb[NFTA_LOG_FLAGS]) {
172  log->flags = ntohl(mnl_attr_get_u32(tb[NFTA_LOG_FLAGS]));
173  e->flags |= (1 << NFTNL_EXPR_LOG_FLAGS);
174  }
175 
176  return 0;
177 }
178 
179 static int
180 nftnl_expr_log_snprintf(char *buf, size_t remain,
181  uint32_t flags, const struct nftnl_expr *e)
182 {
183  struct nftnl_expr_log *log = nftnl_expr_data(e);
184  int ret, offset = 0;
185 
186  if (e->flags & (1 << NFTNL_EXPR_LOG_PREFIX)) {
187  ret = snprintf(buf, remain, "prefix %s ", log->prefix);
188  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
189  }
190 
191  if (e->flags & (1 << NFTNL_EXPR_LOG_GROUP)) {
192  ret = snprintf(buf + offset, remain,
193  "group %u snaplen %u qthreshold %u ",
194  log->group, log->snaplen, log->qthreshold);
195  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
196  } else {
197  if (e->flags & (1 << NFTNL_EXPR_LOG_LEVEL)) {
198  ret = snprintf(buf + offset, remain, "level %u ",
199  log->level);
200  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
201  }
202  if (e->flags & (1 << NFTNL_EXPR_LOG_FLAGS)) {
203  if (log->flags & NF_LOG_TCPSEQ) {
204  ret = snprintf(buf + offset, remain, "tcpseq ");
205  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
206  }
207  if (log->flags & NF_LOG_TCPOPT) {
208  ret = snprintf(buf + offset, remain, "tcpopt ");
209  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
210  }
211  if (log->flags & NF_LOG_IPOPT) {
212  ret = snprintf(buf + offset, remain, "ipopt ");
213  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
214  }
215  if (log->flags & NF_LOG_UID) {
216  ret = snprintf(buf + offset, remain, "uid ");
217  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
218  }
219  if (log->flags & NF_LOG_MACDECODE) {
220  ret = snprintf(buf + offset, remain,
221  "macdecode ");
222  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
223  }
224  }
225  }
226 
227  return offset;
228 }
229 
230 static void nftnl_expr_log_free(const struct nftnl_expr *e)
231 {
232  struct nftnl_expr_log *log = nftnl_expr_data(e);
233 
234  xfree(log->prefix);
235 }
236 
237 static struct attr_policy log_attr_policy[__NFTNL_EXPR_LOG_MAX] = {
238  [NFTNL_EXPR_LOG_PREFIX] = { .maxlen = NF_LOG_PREFIXLEN },
239  [NFTNL_EXPR_LOG_GROUP] = { .maxlen = sizeof(uint16_t) },
240  [NFTNL_EXPR_LOG_SNAPLEN] = { .maxlen = sizeof(uint32_t) },
241  [NFTNL_EXPR_LOG_QTHRESHOLD] = { .maxlen = sizeof(uint16_t) },
242  [NFTNL_EXPR_LOG_LEVEL] = { .maxlen = sizeof(uint32_t) },
243  [NFTNL_EXPR_LOG_FLAGS] = { .maxlen = sizeof(uint32_t) },
244 };
245 
246 struct expr_ops expr_ops_log = {
247  .name = "log",
248  .alloc_len = sizeof(struct nftnl_expr_log),
249  .nftnl_max_attr = __NFTNL_EXPR_LOG_MAX - 1,
250  .attr_policy = log_attr_policy,
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  .output = nftnl_expr_log_snprintf,
257 };
nftnl_expr_log
Definition: log.c:21
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