libnftnl 1.2.9
lookup.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 "internal.h"
9
10#include <stdio.h>
11#include <stdint.h>
12#include <string.h> /* for memcpy */
13#include <arpa/inet.h>
14#include <errno.h>
15#include <libmnl/libmnl.h>
16#include <linux/netfilter/nf_tables.h>
17#include <libnftnl/rule.h>
18#include <libnftnl/expr.h>
19
21 enum nft_registers sreg;
22 enum nft_registers dreg;
23 char *set_name;
24 uint32_t set_id;
25 uint32_t flags;
26};
27
28static int
29nftnl_expr_lookup_set(struct nftnl_expr *e, uint16_t type,
30 const void *data, uint32_t data_len)
31{
32 struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
33
34 switch(type) {
35 case NFTNL_EXPR_LOOKUP_SREG:
36 memcpy(&lookup->sreg, data, data_len);
37 break;
38 case NFTNL_EXPR_LOOKUP_DREG:
39 memcpy(&lookup->dreg, data, data_len);
40 break;
41 case NFTNL_EXPR_LOOKUP_SET:
42 lookup->set_name = strdup((const char *)data);
43 if (!lookup->set_name)
44 return -1;
45 break;
46 case NFTNL_EXPR_LOOKUP_SET_ID:
47 memcpy(&lookup->set_id, data, data_len);
48 break;
49 case NFTNL_EXPR_LOOKUP_FLAGS:
50 memcpy(&lookup->flags, data, data_len);
51 break;
52 }
53 return 0;
54}
55
56static const void *
57nftnl_expr_lookup_get(const struct nftnl_expr *e, uint16_t type,
58 uint32_t *data_len)
59{
60 struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
61
62 switch(type) {
63 case NFTNL_EXPR_LOOKUP_SREG:
64 *data_len = sizeof(lookup->sreg);
65 return &lookup->sreg;
66 case NFTNL_EXPR_LOOKUP_DREG:
67 *data_len = sizeof(lookup->dreg);
68 return &lookup->dreg;
69 case NFTNL_EXPR_LOOKUP_SET:
70 *data_len = strlen(lookup->set_name) + 1;
71 return lookup->set_name;
72 case NFTNL_EXPR_LOOKUP_SET_ID:
73 *data_len = sizeof(lookup->set_id);
74 return &lookup->set_id;
75 case NFTNL_EXPR_LOOKUP_FLAGS:
76 *data_len = sizeof(lookup->flags);
77 return &lookup->flags;
78 }
79 return NULL;
80}
81
82static int nftnl_expr_lookup_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_LOOKUP_MAX) < 0)
88 return MNL_CB_OK;
89
90 switch(type) {
91 case NFTA_LOOKUP_SREG:
92 case NFTA_LOOKUP_DREG:
93 case NFTA_LOOKUP_SET_ID:
94 case NFTA_LOOKUP_FLAGS:
95 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
96 abi_breakage();
97 break;
98 case NFTA_LOOKUP_SET:
99 if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
100 abi_breakage();
101 break;
102 }
103
104 tb[type] = attr;
105 return MNL_CB_OK;
106}
107
108static void
109nftnl_expr_lookup_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
110{
111 struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
112
113 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_SREG))
114 mnl_attr_put_u32(nlh, NFTA_LOOKUP_SREG, htonl(lookup->sreg));
115 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_DREG))
116 mnl_attr_put_u32(nlh, NFTA_LOOKUP_DREG, htonl(lookup->dreg));
117 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_SET))
118 mnl_attr_put_strz(nlh, NFTA_LOOKUP_SET, lookup->set_name);
119 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_SET_ID))
120 mnl_attr_put_u32(nlh, NFTA_LOOKUP_SET_ID,
121 htonl(lookup->set_id));
122 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_FLAGS))
123 mnl_attr_put_u32(nlh, NFTA_LOOKUP_FLAGS, htonl(lookup->flags));
124}
125
126static int
127nftnl_expr_lookup_parse(struct nftnl_expr *e, struct nlattr *attr)
128{
129 struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
130 struct nlattr *tb[NFTA_LOOKUP_MAX+1] = {};
131 int ret = 0;
132
133 if (mnl_attr_parse_nested(attr, nftnl_expr_lookup_cb, tb) < 0)
134 return -1;
135
136 if (tb[NFTA_LOOKUP_SREG]) {
137 lookup->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_SREG]));
138 e->flags |= (1 << NFTNL_EXPR_LOOKUP_SREG);
139 }
140 if (tb[NFTA_LOOKUP_DREG]) {
141 lookup->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_DREG]));
142 e->flags |= (1 << NFTNL_EXPR_LOOKUP_DREG);
143 }
144 if (tb[NFTA_LOOKUP_SET]) {
145 lookup->set_name =
146 strdup(mnl_attr_get_str(tb[NFTA_LOOKUP_SET]));
147 if (!lookup->set_name)
148 return -1;
149 e->flags |= (1 << NFTNL_EXPR_LOOKUP_SET);
150 }
151 if (tb[NFTA_LOOKUP_SET_ID]) {
152 lookup->set_id =
153 ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_SET_ID]));
154 e->flags |= (1 << NFTNL_EXPR_LOOKUP_SET_ID);
155 }
156 if (tb[NFTA_LOOKUP_FLAGS]) {
157 lookup->flags = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_FLAGS]));
158 e->flags |= (1 << NFTNL_EXPR_LOOKUP_FLAGS);
159 }
160
161 return ret;
162}
163
164static int
165nftnl_expr_lookup_snprintf(char *buf, size_t remain,
166 uint32_t flags, const struct nftnl_expr *e)
167{
168 struct nftnl_expr_lookup *l = nftnl_expr_data(e);
169 int offset = 0, ret;
170
171 ret = snprintf(buf, remain, "reg %u set %s ", l->sreg, l->set_name);
172 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
173
174 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_DREG)) {
175 ret = snprintf(buf + offset, remain, "dreg %u ", l->dreg);
176 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
177 }
178
179 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_FLAGS)) {
180 ret = snprintf(buf + offset, remain, "0x%x ", l->flags);
181 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
182 }
183
184 return offset;
185}
186
187static void nftnl_expr_lookup_free(const struct nftnl_expr *e)
188{
189 struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
190
191 xfree(lookup->set_name);
192}
193
194static struct attr_policy lookup_attr_policy[__NFTNL_EXPR_LOOKUP_MAX] = {
195 [NFTNL_EXPR_LOOKUP_SREG] = { .maxlen = sizeof(uint32_t) },
196 [NFTNL_EXPR_LOOKUP_DREG] = { .maxlen = sizeof(uint32_t) },
197 [NFTNL_EXPR_LOOKUP_SET] = { .maxlen = NFT_SET_MAXNAMELEN },
198 [NFTNL_EXPR_LOOKUP_SET_ID] = { .maxlen = sizeof(uint32_t) },
199 [NFTNL_EXPR_LOOKUP_FLAGS] = { .maxlen = sizeof(uint32_t) },
200};
201
202struct expr_ops expr_ops_lookup = {
203 .name = "lookup",
204 .alloc_len = sizeof(struct nftnl_expr_lookup),
205 .nftnl_max_attr = __NFTNL_EXPR_LOOKUP_MAX - 1,
206 .attr_policy = lookup_attr_policy,
207 .free = nftnl_expr_lookup_free,
208 .set = nftnl_expr_lookup_set,
209 .get = nftnl_expr_lookup_get,
210 .parse = nftnl_expr_lookup_parse,
211 .build = nftnl_expr_lookup_build,
212 .output = nftnl_expr_lookup_snprintf,
213};