libnftnl  1.0.6
immediate.c
1 /*
2  * (C) 2012 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 "internal.h"
18 #include <libmnl/libmnl.h>
19 #include <linux/netfilter/nf_tables.h>
20 #include <libnftnl/expr.h>
21 #include <libnftnl/rule.h>
22 
24  union nftnl_data_reg data;
25  enum nft_registers dreg;
26 };
27 
28 static int
29 nftnl_expr_immediate_set(struct nftnl_expr *e, uint16_t type,
30  const void *data, uint32_t data_len)
31 {
32  struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
33 
34  switch(type) {
35  case NFTNL_EXPR_IMM_DREG:
36  imm->dreg = *((uint32_t *)data);
37  break;
38  case NFTNL_EXPR_IMM_DATA:
39  memcpy(&imm->data.val, data, data_len);
40  imm->data.len = data_len;
41  break;
42  case NFTNL_EXPR_IMM_VERDICT:
43  imm->data.verdict = *((uint32_t *)data);
44  break;
45  case NFTNL_EXPR_IMM_CHAIN:
46  if (imm->data.chain)
47  xfree(imm->data.chain);
48 
49  imm->data.chain = strdup(data);
50  break;
51  default:
52  return -1;
53  }
54  return 0;
55 }
56 
57 static const void *
58 nftnl_expr_immediate_get(const struct nftnl_expr *e, uint16_t type,
59  uint32_t *data_len)
60 {
61  struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
62 
63  switch(type) {
64  case NFTNL_EXPR_IMM_DREG:
65  *data_len = sizeof(imm->dreg);
66  return &imm->dreg;
67  case NFTNL_EXPR_IMM_DATA:
68  *data_len = imm->data.len;
69  return &imm->data.val;
70  case NFTNL_EXPR_IMM_VERDICT:
71  *data_len = sizeof(imm->data.verdict);
72  return &imm->data.verdict;
73  case NFTNL_EXPR_IMM_CHAIN:
74  *data_len = strlen(imm->data.chain)+1;
75  return imm->data.chain;
76  }
77  return NULL;
78 }
79 
80 static int nftnl_expr_immediate_cb(const struct nlattr *attr, void *data)
81 {
82  const struct nlattr **tb = data;
83  int type = mnl_attr_get_type(attr);
84 
85  if (mnl_attr_type_valid(attr, NFTA_IMMEDIATE_MAX) < 0)
86  return MNL_CB_OK;
87 
88  switch(type) {
89  case NFTA_IMMEDIATE_DREG:
90  if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
91  abi_breakage();
92  break;
93  case NFTA_IMMEDIATE_DATA:
94  if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0)
95  abi_breakage();
96  break;
97  }
98 
99  tb[type] = attr;
100  return MNL_CB_OK;
101 }
102 
103 static void
104 nftnl_expr_immediate_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
105 {
106  struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
107 
108  if (e->flags & (1 << NFTNL_EXPR_IMM_DREG))
109  mnl_attr_put_u32(nlh, NFTA_IMMEDIATE_DREG, htonl(imm->dreg));
110 
111  /* Sane configurations allows you to set ONLY one of these two below */
112  if (e->flags & (1 << NFTNL_EXPR_IMM_DATA)) {
113  struct nlattr *nest;
114 
115  nest = mnl_attr_nest_start(nlh, NFTA_IMMEDIATE_DATA);
116  mnl_attr_put(nlh, NFTA_DATA_VALUE, imm->data.len, imm->data.val);
117  mnl_attr_nest_end(nlh, nest);
118 
119  } else if (e->flags & (1 << NFTNL_EXPR_IMM_VERDICT)) {
120  struct nlattr *nest1, *nest2;
121 
122  nest1 = mnl_attr_nest_start(nlh, NFTA_IMMEDIATE_DATA);
123  nest2 = mnl_attr_nest_start(nlh, NFTA_DATA_VERDICT);
124  mnl_attr_put_u32(nlh, NFTA_VERDICT_CODE, htonl(imm->data.verdict));
125  if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN))
126  mnl_attr_put_strz(nlh, NFTA_VERDICT_CHAIN, imm->data.chain);
127 
128  mnl_attr_nest_end(nlh, nest1);
129  mnl_attr_nest_end(nlh, nest2);
130  }
131 }
132 
133 static int
134 nftnl_expr_immediate_parse(struct nftnl_expr *e, struct nlattr *attr)
135 {
136  struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
137  struct nlattr *tb[NFTA_IMMEDIATE_MAX+1] = {};
138  int ret = 0;
139 
140  if (mnl_attr_parse_nested(attr, nftnl_expr_immediate_cb, tb) < 0)
141  return -1;
142 
143  if (tb[NFTA_IMMEDIATE_DREG]) {
144  imm->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_IMMEDIATE_DREG]));
145  e->flags |= (1 << NFTNL_EXPR_IMM_DREG);
146  }
147  if (tb[NFTA_IMMEDIATE_DATA]) {
148  int type;
149 
150  ret = nftnl_parse_data(&imm->data, tb[NFTA_IMMEDIATE_DATA], &type);
151  if (ret < 0)
152  return ret;
153 
154  switch(type) {
155  case DATA_VALUE:
156  /* real immediate data to be loaded to destination */
157  e->flags |= (1 << NFTNL_EXPR_IMM_DATA);
158  break;
159  case DATA_VERDICT:
160  /* NF_ACCEPT, NF_DROP, NF_QUEUE and NFTNL_RETURN case */
161  e->flags |= (1 << NFTNL_EXPR_IMM_VERDICT);
162  break;
163  case DATA_CHAIN:
164  /* NFTNL_GOTO and NFTNL_JUMP case */
165  e->flags |= (1 << NFTNL_EXPR_IMM_VERDICT) |
166  (1 << NFTNL_EXPR_IMM_CHAIN);
167  break;
168  }
169  }
170 
171  return ret;
172 }
173 
174 static int
175 nftnl_expr_immediate_json_parse(struct nftnl_expr *e, json_t *root,
176  struct nftnl_parse_err *err)
177 {
178 #ifdef JSON_PARSING
179  struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
180  int datareg_type;
181  uint32_t reg;
182 
183  if (nftnl_jansson_parse_reg(root, "dreg", NFTNL_TYPE_U32, &reg, err) == 0)
184  nftnl_expr_set_u32(e, NFTNL_EXPR_IMM_DREG, reg);
185 
186  datareg_type = nftnl_jansson_data_reg_parse(root, "data",
187  &imm->data, err);
188  if (datareg_type >= 0) {
189  switch (datareg_type) {
190  case DATA_VALUE:
191  e->flags |= (1 << NFTNL_EXPR_IMM_DATA);
192  break;
193  case DATA_VERDICT:
194  e->flags |= (1 << NFTNL_EXPR_IMM_VERDICT);
195  break;
196  case DATA_CHAIN:
197  e->flags |= (1 << NFTNL_EXPR_IMM_CHAIN);
198  break;
199  default:
200  return -1;
201  }
202  }
203  return 0;
204 #else
205  errno = EOPNOTSUPP;
206  return -1;
207 #endif
208 }
209 
210 static int
211 nftnl_expr_immediate_xml_parse(struct nftnl_expr *e, mxml_node_t *tree,
212  struct nftnl_parse_err *err)
213 {
214 #ifdef XML_PARSING
215  struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
216  int datareg_type;
217  uint32_t reg;
218 
219  if (nftnl_mxml_reg_parse(tree, "dreg", &reg, MXML_DESCEND_FIRST,
220  NFTNL_XML_MAND, err) == 0)
221  nftnl_expr_set_u32(e, NFTNL_EXPR_IMM_DREG, reg);
222 
223  datareg_type = nftnl_mxml_data_reg_parse(tree, "data",
224  &imm->data, NFTNL_XML_MAND, err);
225  if (datareg_type >= 0) {
226  switch (datareg_type) {
227  case DATA_VALUE:
228  e->flags |= (1 << NFTNL_EXPR_IMM_DATA);
229  break;
230  case DATA_VERDICT:
231  e->flags |= (1 << NFTNL_EXPR_IMM_VERDICT);
232  break;
233  case DATA_CHAIN:
234  e->flags |= (1 << NFTNL_EXPR_IMM_CHAIN);
235  break;
236  default:
237  return -1;
238  }
239  }
240 
241  return 0;
242 #else
243  errno = EOPNOTSUPP;
244  return -1;
245 #endif
246 }
247 
248 static int
249 nftnl_expr_immediate_export(char *buf, size_t size, const struct nftnl_expr *e,
250  int type)
251 {
252  struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
253  NFTNL_BUF_INIT(b, buf, size);
254 
255  if (e->flags & (1 << NFTNL_EXPR_IMM_DREG))
256  nftnl_buf_u32(&b, type, imm->dreg, DREG);
257  if (e->flags & (1 << NFTNL_EXPR_IMM_DATA))
258  nftnl_buf_reg(&b, type, &imm->data, DATA_VALUE, DATA);
259  if (e->flags & (1 << NFTNL_EXPR_IMM_VERDICT))
260  nftnl_buf_reg(&b, type, &imm->data, DATA_VERDICT, DATA);
261  if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN))
262  nftnl_buf_reg(&b, type, &imm->data, DATA_CHAIN, DATA);
263 
264  return nftnl_buf_done(&b);
265 }
266 
267 static int
268 nftnl_expr_immediate_snprintf_default(char *buf, size_t len,
269  const struct nftnl_expr *e,
270  uint32_t flags)
271 {
272  int size = len, offset = 0, ret;
273  struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
274 
275  ret = snprintf(buf, len, "reg %u ", imm->dreg);
276  SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
277 
278  if (e->flags & (1 << NFTNL_EXPR_IMM_DATA)) {
279  ret = nftnl_data_reg_snprintf(buf+offset, len, &imm->data,
280  NFTNL_OUTPUT_DEFAULT, flags, DATA_VALUE);
281  SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
282 
283  } else if (e->flags & (1 << NFTNL_EXPR_IMM_VERDICT)) {
284  ret = nftnl_data_reg_snprintf(buf+offset, len, &imm->data,
285  NFTNL_OUTPUT_DEFAULT, flags, DATA_VERDICT);
286  SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
287 
288  } else if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN)) {
289  ret = nftnl_data_reg_snprintf(buf+offset, len, &imm->data,
290  NFTNL_OUTPUT_DEFAULT, flags, DATA_CHAIN);
291  SNPRINTF_BUFFER_SIZE(ret, size, len, offset);
292  }
293 
294  return offset;
295 }
296 
297 static int
298 nftnl_expr_immediate_snprintf(char *buf, size_t len, uint32_t type,
299  uint32_t flags, const struct nftnl_expr *e)
300 {
301  switch(type) {
302  case NFTNL_OUTPUT_DEFAULT:
303  return nftnl_expr_immediate_snprintf_default(buf, len, e, flags);
304  case NFTNL_OUTPUT_XML:
305  case NFTNL_OUTPUT_JSON:
306  return nftnl_expr_immediate_export(buf, len, e, type);
307  default:
308  break;
309  }
310  return -1;
311 }
312 
313 static void nftnl_expr_immediate_free(const struct nftnl_expr *e)
314 {
315  struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
316 
317  if (e->flags & (1 << NFTNL_EXPR_IMM_VERDICT))
318  nftnl_free_verdict(&imm->data);
319 }
320 
321 struct expr_ops expr_ops_immediate = {
322  .name = "immediate",
323  .alloc_len = sizeof(struct nftnl_expr_immediate),
324  .max_attr = NFTA_IMMEDIATE_MAX,
325  .free = nftnl_expr_immediate_free,
326  .set = nftnl_expr_immediate_set,
327  .get = nftnl_expr_immediate_get,
328  .parse = nftnl_expr_immediate_parse,
329  .build = nftnl_expr_immediate_build,
330  .snprintf = nftnl_expr_immediate_snprintf,
331  .xml_parse = nftnl_expr_immediate_xml_parse,
332  .json_parse = nftnl_expr_immediate_json_parse,
333 };