libnftnl 1.2.8
match.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 "internal.h"
13
14#include <stdio.h>
15#include <stdint.h>
16#include <string.h> /* for memcpy */
17#include <arpa/inet.h>
18#include <errno.h>
19#include <libmnl/libmnl.h>
20
21#include <linux/netfilter/nf_tables.h>
22#include <linux/netfilter/nf_tables_compat.h>
23
24#include <libnftnl/expr.h>
25#include <libnftnl/rule.h>
26
27/* From include/linux/netfilter/x_tables.h */
28#define XT_EXTENSION_MAXNAMELEN 29
29
31 char name[XT_EXTENSION_MAXNAMELEN];
32 uint32_t rev;
33 uint32_t data_len;
34 const void *data;
35};
36
37static int
38nftnl_expr_match_set(struct nftnl_expr *e, uint16_t type,
39 const void *data, uint32_t data_len)
40{
41 struct nftnl_expr_match *mt = nftnl_expr_data(e);
42
43 switch(type) {
44 case NFTNL_EXPR_MT_NAME:
45 snprintf(mt->name, sizeof(mt->name), "%.*s", data_len,
46 (const char *)data);
47 break;
48 case NFTNL_EXPR_MT_REV:
49 memcpy(&mt->rev, data, data_len);
50 break;
51 case NFTNL_EXPR_MT_INFO:
52 if (e->flags & (1 << NFTNL_EXPR_MT_INFO))
53 xfree(mt->data);
54
55 mt->data = data;
56 mt->data_len = data_len;
57 break;
58 }
59 return 0;
60}
61
62static const void *
63nftnl_expr_match_get(const struct nftnl_expr *e, uint16_t type,
64 uint32_t *data_len)
65{
66 struct nftnl_expr_match *mt = nftnl_expr_data(e);
67
68 switch(type) {
69 case NFTNL_EXPR_MT_NAME:
70 *data_len = sizeof(mt->name);
71 return mt->name;
72 case NFTNL_EXPR_MT_REV:
73 *data_len = sizeof(mt->rev);
74 return &mt->rev;
75 case NFTNL_EXPR_MT_INFO:
76 *data_len = mt->data_len;
77 return mt->data;
78 }
79 return NULL;
80}
81
82static int nftnl_expr_match_cb(const struct nlattr *attr, void *data)
83{
84 const struct nlattr **tb = data;
85 int type = mnl_attr_get_type(attr);
86
87 if (mnl_attr_type_valid(attr, NFTA_MATCH_MAX) < 0)
88 return MNL_CB_OK;
89
90 switch(type) {
91 case NFTA_MATCH_NAME:
92 if (mnl_attr_validate(attr, MNL_TYPE_NUL_STRING) < 0)
93 abi_breakage();
94 break;
95 case NFTA_MATCH_REV:
96 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
97 abi_breakage();
98 break;
99 case NFTA_MATCH_INFO:
100 if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0)
101 abi_breakage();
102 break;
103 }
104
105 tb[type] = attr;
106 return MNL_CB_OK;
107}
108
109static void
110nftnl_expr_match_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
111{
112 struct nftnl_expr_match *mt = nftnl_expr_data(e);
113
114 if (e->flags & (1 << NFTNL_EXPR_MT_NAME))
115 mnl_attr_put_strz(nlh, NFTA_MATCH_NAME, mt->name);
116 if (e->flags & (1 << NFTNL_EXPR_MT_REV))
117 mnl_attr_put_u32(nlh, NFTA_MATCH_REV, htonl(mt->rev));
118 if (e->flags & (1 << NFTNL_EXPR_MT_INFO))
119 mnl_attr_put(nlh, NFTA_MATCH_INFO, mt->data_len, mt->data);
120}
121
122static int nftnl_expr_match_parse(struct nftnl_expr *e, struct nlattr *attr)
123{
124 struct nftnl_expr_match *match = nftnl_expr_data(e);
125 struct nlattr *tb[NFTA_MATCH_MAX+1] = {};
126
127 if (mnl_attr_parse_nested(attr, nftnl_expr_match_cb, tb) < 0)
128 return -1;
129
130 if (tb[NFTA_MATCH_NAME]) {
131 snprintf(match->name, XT_EXTENSION_MAXNAMELEN, "%s",
132 mnl_attr_get_str(tb[NFTA_MATCH_NAME]));
133
134 match->name[XT_EXTENSION_MAXNAMELEN-1] = '\0';
135 e->flags |= (1 << NFTNL_EXPR_MT_NAME);
136 }
137
138 if (tb[NFTA_MATCH_REV]) {
139 match->rev = ntohl(mnl_attr_get_u32(tb[NFTA_MATCH_REV]));
140 e->flags |= (1 << NFTNL_EXPR_MT_REV);
141 }
142
143 if (tb[NFTA_MATCH_INFO]) {
144 uint32_t len = mnl_attr_get_payload_len(tb[NFTA_MATCH_INFO]);
145 void *match_data;
146
147 if (e->flags & (1 << NFTNL_EXPR_MT_INFO))
148 xfree(match->data);
149
150 match_data = calloc(1, len);
151 if (match_data == NULL)
152 return -1;
153
154 memcpy(match_data, mnl_attr_get_payload(tb[NFTA_MATCH_INFO]), len);
155
156 match->data = match_data;
157 match->data_len = len;
158
159 e->flags |= (1 << NFTNL_EXPR_MT_INFO);
160 }
161
162 return 0;
163}
164
165static int
166nftnl_expr_match_snprintf(char *buf, size_t len,
167 uint32_t flags, const struct nftnl_expr *e)
168{
169 struct nftnl_expr_match *match = nftnl_expr_data(e);
170
171 return snprintf(buf, len, "name %s rev %u ", match->name, match->rev);
172}
173
174static void nftnl_expr_match_free(const struct nftnl_expr *e)
175{
176 struct nftnl_expr_match *match = nftnl_expr_data(e);
177
178 xfree(match->data);
179}
180
181static struct attr_policy match_attr_policy[__NFTNL_EXPR_MT_MAX] = {
182 [NFTNL_EXPR_MT_NAME] = { .maxlen = XT_EXTENSION_MAXNAMELEN },
183 [NFTNL_EXPR_MT_REV] = { .maxlen = sizeof(uint32_t) },
184 [NFTNL_EXPR_MT_INFO] = { .maxlen = 0 },
185};
186
187struct expr_ops expr_ops_match = {
188 .name = "match",
189 .alloc_len = sizeof(struct nftnl_expr_match),
190 .nftnl_max_attr = __NFTNL_EXPR_MT_MAX - 1,
191 .attr_policy = match_attr_policy,
192 .free = nftnl_expr_match_free,
193 .set = nftnl_expr_match_set,
194 .get = nftnl_expr_match_get,
195 .parse = nftnl_expr_match_parse,
196 .build = nftnl_expr_match_build,
197 .output = nftnl_expr_match_snprintf,
198};