libnftnl 1.2.7
expr.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#include "internal.h"
12
13#include <time.h>
14#include <endian.h>
15#include <stdint.h>
16#include <stdlib.h>
17#include <string.h>
18#include <errno.h>
19#include <netinet/in.h>
20
21#include <libmnl/libmnl.h>
22#include <linux/netfilter/nfnetlink.h>
23#include <linux/netfilter/nf_tables.h>
24
25#include <libnftnl/expr.h>
26
27EXPORT_SYMBOL(nftnl_expr_alloc);
28struct nftnl_expr *nftnl_expr_alloc(const char *name)
29{
30 struct nftnl_expr *expr;
31 struct expr_ops *ops;
32
33 ops = nftnl_expr_ops_lookup(name);
34 if (ops == NULL)
35 return NULL;
36
37 expr = calloc(1, sizeof(struct nftnl_expr) + ops->alloc_len);
38 if (expr == NULL)
39 return NULL;
40
41 /* Manually set expression name attribute */
42 expr->flags |= (1 << NFTNL_EXPR_NAME);
43 expr->ops = ops;
44
45 if (ops->init)
46 ops->init(expr);
47
48 return expr;
49}
50
51EXPORT_SYMBOL(nftnl_expr_free);
52void nftnl_expr_free(const struct nftnl_expr *expr)
53{
54 if (expr->ops->free)
55 expr->ops->free(expr);
56
57 xfree(expr);
58}
59
60EXPORT_SYMBOL(nftnl_expr_is_set);
61bool nftnl_expr_is_set(const struct nftnl_expr *expr, uint16_t type)
62{
63 return expr->flags & (1 << type);
64}
65
66EXPORT_SYMBOL(nftnl_expr_set);
67int nftnl_expr_set(struct nftnl_expr *expr, uint16_t type,
68 const void *data, uint32_t data_len)
69{
70 switch(type) {
71 case NFTNL_EXPR_NAME: /* cannot be modified */
72 return 0;
73 default:
74 if (type < NFTNL_EXPR_BASE || type > expr->ops->nftnl_max_attr)
75 return -1;
76
77 if (!expr->ops->attr_policy)
78 return -1;
79
80 if (expr->ops->attr_policy[type].maxlen &&
81 expr->ops->attr_policy[type].maxlen < data_len)
82 return -1;
83
84 if (expr->ops->set(expr, type, data, data_len) < 0)
85 return -1;
86 }
87 expr->flags |= (1 << type);
88 return 0;
89}
90
91EXPORT_SYMBOL(nftnl_expr_set_u8);
92void
93nftnl_expr_set_u8(struct nftnl_expr *expr, uint16_t type, uint8_t data)
94{
95 nftnl_expr_set(expr, type, &data, sizeof(uint8_t));
96}
97
98EXPORT_SYMBOL(nftnl_expr_set_u16);
99void
100nftnl_expr_set_u16(struct nftnl_expr *expr, uint16_t type, uint16_t data)
101{
102 nftnl_expr_set(expr, type, &data, sizeof(uint16_t));
103}
104
105EXPORT_SYMBOL(nftnl_expr_set_u32);
106void
107nftnl_expr_set_u32(struct nftnl_expr *expr, uint16_t type, uint32_t data)
108{
109 nftnl_expr_set(expr, type, &data, sizeof(uint32_t));
110}
111
112EXPORT_SYMBOL(nftnl_expr_set_u64);
113void
114nftnl_expr_set_u64(struct nftnl_expr *expr, uint16_t type, uint64_t data)
115{
116 nftnl_expr_set(expr, type, &data, sizeof(uint64_t));
117}
118
119EXPORT_SYMBOL(nftnl_expr_set_str);
120int nftnl_expr_set_str(struct nftnl_expr *expr, uint16_t type, const char *str)
121{
122 return nftnl_expr_set(expr, type, str, strlen(str) + 1);
123}
124
125EXPORT_SYMBOL(nftnl_expr_get);
126const void *nftnl_expr_get(const struct nftnl_expr *expr,
127 uint16_t type, uint32_t *data_len)
128{
129 const void *ret;
130
131 if (!(expr->flags & (1 << type)))
132 return NULL;
133
134 switch(type) {
135 case NFTNL_EXPR_NAME:
136 *data_len = strlen(expr->ops->name) + 1;
137 ret = expr->ops->name;
138 break;
139 default:
140 ret = expr->ops->get(expr, type, data_len);
141 break;
142 }
143
144 return ret;
145}
146
147EXPORT_SYMBOL(nftnl_expr_get_u8);
148uint8_t nftnl_expr_get_u8(const struct nftnl_expr *expr, uint16_t type)
149{
150 const void *data;
151 uint32_t data_len;
152
153 data = nftnl_expr_get(expr, type, &data_len);
154 if (data == NULL)
155 return 0;
156
157 if (data_len != sizeof(uint8_t))
158 return 0;
159
160 return *((uint8_t *)data);
161}
162
163EXPORT_SYMBOL(nftnl_expr_get_u16);
164uint16_t nftnl_expr_get_u16(const struct nftnl_expr *expr, uint16_t type)
165{
166 const void *data;
167 uint32_t data_len;
168
169 data = nftnl_expr_get(expr, type, &data_len);
170 if (data == NULL)
171 return 0;
172
173 if (data_len != sizeof(uint16_t))
174 return 0;
175
176 return *((uint16_t *)data);
177}
178
179EXPORT_SYMBOL(nftnl_expr_get_u32);
180uint32_t nftnl_expr_get_u32(const struct nftnl_expr *expr, uint16_t type)
181{
182 const void *data;
183 uint32_t data_len;
184
185 data = nftnl_expr_get(expr, type, &data_len);
186 if (data == NULL)
187 return 0;
188
189 if (data_len != sizeof(uint32_t))
190 return 0;
191
192 return *((uint32_t *)data);
193}
194
195EXPORT_SYMBOL(nftnl_expr_get_u64);
196uint64_t nftnl_expr_get_u64(const struct nftnl_expr *expr, uint16_t type)
197{
198 const void *data;
199 uint32_t data_len;
200
201 data = nftnl_expr_get(expr, type, &data_len);
202 if (data == NULL)
203 return 0;
204
205 if (data_len != sizeof(uint64_t))
206 return 0;
207
208 return *((uint64_t *)data);
209}
210
211EXPORT_SYMBOL(nftnl_expr_get_str);
212const char *nftnl_expr_get_str(const struct nftnl_expr *expr, uint16_t type)
213{
214 uint32_t data_len;
215
216 return (const char *)nftnl_expr_get(expr, type, &data_len);
217}
218
219EXPORT_SYMBOL(nftnl_expr_build_payload);
220void nftnl_expr_build_payload(struct nlmsghdr *nlh, struct nftnl_expr *expr)
221{
222 struct nlattr *nest;
223
224 mnl_attr_put_strz(nlh, NFTA_EXPR_NAME, expr->ops->name);
225
226 if (!expr->ops->build)
227 return;
228
229 nest = mnl_attr_nest_start(nlh, NFTA_EXPR_DATA);
230 expr->ops->build(nlh, expr);
231 mnl_attr_nest_end(nlh, nest);
232}
233
234static int nftnl_rule_parse_expr_cb(const struct nlattr *attr, void *data)
235{
236 const struct nlattr **tb = data;
237 int type = mnl_attr_get_type(attr);
238
239 if (mnl_attr_type_valid(attr, NFTA_EXPR_MAX) < 0)
240 return MNL_CB_OK;
241
242 switch (type) {
243 case NFTA_EXPR_NAME:
244 if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
245 abi_breakage();
246 break;
247 case NFTA_EXPR_DATA:
248 if (mnl_attr_validate(attr, MNL_TYPE_NESTED) < 0)
249 abi_breakage();
250 break;
251 }
252
253 tb[type] = attr;
254 return MNL_CB_OK;
255}
256
257struct nftnl_expr *nftnl_expr_parse(struct nlattr *attr)
258{
259 struct nlattr *tb[NFTA_EXPR_MAX+1] = {};
260 struct nftnl_expr *expr;
261
262 if (mnl_attr_parse_nested(attr, nftnl_rule_parse_expr_cb, tb) < 0)
263 goto err1;
264
265 expr = nftnl_expr_alloc(mnl_attr_get_str(tb[NFTA_EXPR_NAME]));
266 if (expr == NULL)
267 goto err1;
268
269 if (tb[NFTA_EXPR_DATA] &&
270 expr->ops->parse &&
271 expr->ops->parse(expr, tb[NFTA_EXPR_DATA]) < 0)
272 goto err2;
273
274 return expr;
275
276err2:
277 xfree(expr);
278err1:
279 return NULL;
280}
281
282EXPORT_SYMBOL(nftnl_expr_snprintf);
283int nftnl_expr_snprintf(char *buf, size_t remain, const struct nftnl_expr *expr,
284 uint32_t type, uint32_t flags)
285{
286 int ret;
287 unsigned int offset = 0;
288
289 if (remain)
290 buf[0] = '\0';
291
292 if (!expr->ops->output || type != NFTNL_OUTPUT_DEFAULT)
293 return 0;
294
295 ret = expr->ops->output(buf + offset, remain, flags, expr);
296 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
297
298 return offset;
299}
300
301static int nftnl_expr_do_snprintf(char *buf, size_t size, const void *e,
302 uint32_t cmd, uint32_t type, uint32_t flags)
303{
304 return nftnl_expr_snprintf(buf, size, e, type, flags);
305}
306
307EXPORT_SYMBOL(nftnl_expr_fprintf);
308int nftnl_expr_fprintf(FILE *fp, const struct nftnl_expr *expr, uint32_t type,
309 uint32_t flags)
310{
311 return nftnl_fprintf(fp, expr, NFTNL_CMD_UNSPEC, type, flags,
312 nftnl_expr_do_snprintf);
313}