libnftnl  1.1.5
data_reg.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 <limits.h>
16 #include <arpa/inet.h>
17 #include <errno.h>
18 #include <netinet/in.h>
19 
20 #include <libmnl/libmnl.h>
21 #include <linux/netfilter.h>
22 #include <linux/netfilter/nf_tables.h>
23 #include <libnftnl/expr.h>
24 #include <libnftnl/rule.h>
25 #include "internal.h"
26 
27 static int
28 nftnl_data_reg_value_snprintf_default(char *buf, size_t size,
29  const union nftnl_data_reg *reg,
30  uint32_t flags)
31 {
32  int remain = size, offset = 0, ret, i;
33 
34  for (i = 0; i < div_round_up(reg->len, sizeof(uint32_t)); i++) {
35  ret = snprintf(buf + offset, remain, "0x%.8x ", reg->val[i]);
36  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
37  }
38 
39  return offset;
40 }
41 
42 static int
43 nftnl_data_reg_verdict_snprintf_def(char *buf, size_t size,
44  const union nftnl_data_reg *reg,
45  uint32_t flags)
46 {
47  int remain = size, offset = 0, ret = 0;
48 
49  ret = snprintf(buf, size, "%s ", nftnl_verdict2str(reg->verdict));
50  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
51 
52  if (reg->chain != NULL) {
53  ret = snprintf(buf + offset, remain, "-> %s ", reg->chain);
54  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
55  }
56 
57  return offset;
58 }
59 
60 int nftnl_data_reg_snprintf(char *buf, size_t size,
61  const union nftnl_data_reg *reg,
62  uint32_t output_format, uint32_t flags,
63  int reg_type)
64 {
65  switch(reg_type) {
66  case DATA_VALUE:
67  switch(output_format) {
68  case NFTNL_OUTPUT_DEFAULT:
69  return nftnl_data_reg_value_snprintf_default(buf, size,
70  reg, flags);
71  case NFTNL_OUTPUT_JSON:
72  case NFTNL_OUTPUT_XML:
73  default:
74  break;
75  }
76  break;
77  case DATA_VERDICT:
78  case DATA_CHAIN:
79  switch(output_format) {
80  case NFTNL_OUTPUT_DEFAULT:
81  return nftnl_data_reg_verdict_snprintf_def(buf, size,
82  reg, flags);
83  case NFTNL_OUTPUT_JSON:
84  case NFTNL_OUTPUT_XML:
85  default:
86  break;
87  }
88  break;
89  default:
90  break;
91  }
92 
93  return -1;
94 }
95 
96 static int nftnl_data_parse_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_DATA_MAX) < 0)
102  return MNL_CB_OK;
103 
104  switch(type) {
105  case NFTA_DATA_VALUE:
106  if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0)
107  abi_breakage();
108  break;
109  case NFTA_DATA_VERDICT:
110  if (mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0)
111  abi_breakage();
112  break;
113  }
114  tb[type] = attr;
115  return MNL_CB_OK;
116 }
117 
118 static int nftnl_verdict_parse_cb(const struct nlattr *attr, void *data)
119 {
120  const struct nlattr **tb = data;
121  int type = mnl_attr_get_type(attr);
122 
123  if (mnl_attr_type_valid(attr, NFTA_VERDICT_MAX) < 0)
124  return MNL_CB_OK;
125 
126  switch(type) {
127  case NFTA_VERDICT_CODE:
128  if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
129  abi_breakage();
130  break;
131  case NFTA_VERDICT_CHAIN:
132  if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
133  abi_breakage();
134  break;
135  }
136  tb[type] = attr;
137  return MNL_CB_OK;
138 }
139 
140 static int
141 nftnl_parse_verdict(union nftnl_data_reg *data, const struct nlattr *attr, int *type)
142 {
143  struct nlattr *tb[NFTA_VERDICT_MAX+1];
144 
145  if (mnl_attr_parse_nested(attr, nftnl_verdict_parse_cb, tb) < 0)
146  return -1;
147 
148  if (!tb[NFTA_VERDICT_CODE])
149  return -1;
150 
151  data->verdict = ntohl(mnl_attr_get_u32(tb[NFTA_VERDICT_CODE]));
152 
153  switch(data->verdict) {
154  case NF_ACCEPT:
155  case NF_DROP:
156  case NF_QUEUE:
157  case NFT_CONTINUE:
158  case NFT_BREAK:
159  case NFT_RETURN:
160  if (type)
161  *type = DATA_VERDICT;
162  data->len = sizeof(data->verdict);
163  break;
164  case NFT_JUMP:
165  case NFT_GOTO:
166  if (!tb[NFTA_VERDICT_CHAIN])
167  return -1;
168 
169  data->chain = strdup(mnl_attr_get_str(tb[NFTA_VERDICT_CHAIN]));
170  if (!data->chain)
171  return -1;
172 
173  if (type)
174  *type = DATA_CHAIN;
175  break;
176  default:
177  return -1;
178  }
179 
180  return 0;
181 }
182 
183 static int
184 __nftnl_parse_data(union nftnl_data_reg *data, const struct nlattr *attr)
185 {
186  void *orig = mnl_attr_get_payload(attr);
187  uint32_t data_len = mnl_attr_get_payload_len(attr);
188 
189  if (data_len == 0)
190  return -1;
191 
192  if (data_len > sizeof(data->val))
193  return -1;
194 
195  memcpy(data->val, orig, data_len);
196  data->len = data_len;
197 
198  return 0;
199 }
200 
201 int nftnl_parse_data(union nftnl_data_reg *data, struct nlattr *attr, int *type)
202 {
203  struct nlattr *tb[NFTA_DATA_MAX+1] = {};
204  int ret = 0;
205 
206  if (mnl_attr_parse_nested(attr, nftnl_data_parse_cb, tb) < 0)
207  return -1;
208 
209  if (tb[NFTA_DATA_VALUE]) {
210  if (type)
211  *type = DATA_VALUE;
212 
213  ret = __nftnl_parse_data(data, tb[NFTA_DATA_VALUE]);
214  if (ret < 0)
215  return ret;
216  }
217  if (tb[NFTA_DATA_VERDICT])
218  ret = nftnl_parse_verdict(data, tb[NFTA_DATA_VERDICT], type);
219 
220  return ret;
221 }
222 
223 void nftnl_free_verdict(const union nftnl_data_reg *data)
224 {
225  switch(data->verdict) {
226  case NFT_JUMP:
227  case NFT_GOTO:
228  xfree(data->chain);
229  break;
230  default:
231  break;
232  }
233 }