libnftnl 1.3.2
immediate.c
1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * (C) 2012 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 <stdio.h>
9#include <stdint.h>
10#include <string.h>
11#include <arpa/inet.h>
12#include <errno.h>
13#include "internal.h"
14#include <libmnl/libmnl.h>
15#include <linux/netfilter/nf_tables.h>
16#include <libnftnl/expr.h>
17#include <libnftnl/rule.h>
18
19struct nftnl_expr_immediate {
20 union nftnl_data_reg data;
21 enum nft_registers dreg;
22};
23
24static int
25nftnl_expr_immediate_set(struct nftnl_expr *e, uint16_t type,
26 const void *data, uint32_t data_len, uint32_t byteorder)
27{
28 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
29
30 switch(type) {
31 case NFTNL_EXPR_IMM_DREG:
32 memcpy(&imm->dreg, data, data_len);
33 break;
34 case NFTNL_EXPR_IMM_DATA:
35 return nftnl_data_cpy(&imm->data, data,
36 data_len, byteorder, NULL);
37 case NFTNL_EXPR_IMM_VERDICT:
38 memcpy(&imm->data.verdict, data, data_len);
39 break;
40 case NFTNL_EXPR_IMM_CHAIN:
41 if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN))
42 xfree(imm->data.chain);
43
44 imm->data.chain = strdup(data);
45 if (!imm->data.chain)
46 return -1;
47 break;
48 case NFTNL_EXPR_IMM_CHAIN_ID:
49 memcpy(&imm->data.chain_id, data, data_len);
50 break;
51 }
52 return 0;
53}
54
55static const void *
56nftnl_expr_immediate_get(const struct nftnl_expr *e, uint16_t type,
57 uint32_t *data_len)
58{
59 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
60
61 switch(type) {
62 case NFTNL_EXPR_IMM_DREG:
63 *data_len = sizeof(imm->dreg);
64 return &imm->dreg;
65 case NFTNL_EXPR_IMM_DATA:
66 *data_len = imm->data.len;
67 return &imm->data.val;
68 case NFTNL_EXPR_IMM_VERDICT:
69 *data_len = sizeof(imm->data.verdict);
70 return &imm->data.verdict;
71 case NFTNL_EXPR_IMM_CHAIN:
72 *data_len = strlen(imm->data.chain)+1;
73 return imm->data.chain;
74 case NFTNL_EXPR_IMM_CHAIN_ID:
75 *data_len = sizeof(imm->data.chain_id);
76 return &imm->data.chain_id;
77 }
78 return NULL;
79}
80
81static int nftnl_expr_immediate_cb(const struct nlattr *attr, void *data)
82{
83 const struct nlattr **tb = data;
84 int type = mnl_attr_get_type(attr);
85
86 if (mnl_attr_type_valid(attr, NFTA_IMMEDIATE_MAX) < 0)
87 return MNL_CB_OK;
88
89 switch(type) {
90 case NFTA_IMMEDIATE_DREG:
91 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
92 abi_breakage();
93 break;
94 case NFTA_IMMEDIATE_DATA:
95 if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0)
96 abi_breakage();
97 break;
98 }
99
100 tb[type] = attr;
101 return MNL_CB_OK;
102}
103
104static void
105nftnl_expr_immediate_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
106{
107 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
108
109 if (e->flags & (1 << NFTNL_EXPR_IMM_DREG))
110 mnl_attr_put_u32(nlh, NFTA_IMMEDIATE_DREG, htonl(imm->dreg));
111
112 /* Sane configurations allows you to set ONLY one of these two below */
113 if (e->flags & (1 << NFTNL_EXPR_IMM_DATA)) {
114 struct nlattr *nest;
115
116 nest = mnl_attr_nest_start(nlh, NFTA_IMMEDIATE_DATA);
117 mnl_attr_put(nlh, NFTA_DATA_VALUE, imm->data.len, imm->data.val);
118 mnl_attr_nest_end(nlh, nest);
119
120 } else if (e->flags & (1 << NFTNL_EXPR_IMM_VERDICT)) {
121 struct nlattr *nest1, *nest2;
122
123 nest1 = mnl_attr_nest_start(nlh, NFTA_IMMEDIATE_DATA);
124 nest2 = mnl_attr_nest_start(nlh, NFTA_DATA_VERDICT);
125 mnl_attr_put_u32(nlh, NFTA_VERDICT_CODE, htonl(imm->data.verdict));
126 if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN))
127 mnl_attr_put_strz(nlh, NFTA_VERDICT_CHAIN, imm->data.chain);
128 if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN_ID)) {
129 mnl_attr_put_u32(nlh, NFTA_VERDICT_CHAIN_ID,
130 htonl(imm->data.chain_id));
131 }
132
133 mnl_attr_nest_end(nlh, nest1);
134 mnl_attr_nest_end(nlh, nest2);
135 }
136}
137
138static int
139nftnl_expr_immediate_parse(struct nftnl_expr *e, struct nlattr *attr)
140{
141 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
142 struct nlattr *tb[NFTA_IMMEDIATE_MAX+1] = {};
143 int ret = 0;
144
145 if (mnl_attr_parse_nested(attr, nftnl_expr_immediate_cb, tb) < 0)
146 return -1;
147
148 if (tb[NFTA_IMMEDIATE_DREG]) {
149 imm->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_IMMEDIATE_DREG]));
150 e->flags |= (1 << NFTNL_EXPR_IMM_DREG);
151 }
152 if (tb[NFTA_IMMEDIATE_DATA]) {
153 int type;
154
155 ret = nftnl_parse_data(&imm->data, tb[NFTA_IMMEDIATE_DATA], &type);
156 if (ret < 0)
157 return ret;
158
159 switch(type) {
160 case DATA_VALUE:
161 /* real immediate data to be loaded to destination */
162 e->flags |= (1 << NFTNL_EXPR_IMM_DATA);
163 break;
164 case DATA_VERDICT:
165 /* NF_ACCEPT, NF_DROP, NF_QUEUE and NFTNL_RETURN case */
166 e->flags |= (1 << NFTNL_EXPR_IMM_VERDICT);
167 break;
168 case DATA_CHAIN:
169 /* NFTNL_GOTO and NFTNL_JUMP case */
170 e->flags |= (1 << NFTNL_EXPR_IMM_VERDICT) |
171 (1 << NFTNL_EXPR_IMM_CHAIN);
172 break;
173 }
174 }
175
176 return ret;
177}
178
179static int
180nftnl_expr_immediate_snprintf(char *buf, size_t remain,
181 uint32_t flags, const struct nftnl_expr *e)
182{
183 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
184 int offset = 0, ret;
185
186 ret = snprintf(buf, remain, "reg %u ", imm->dreg);
187 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
188
189 if (e->flags & (1 << NFTNL_EXPR_IMM_DATA)) {
190 ret = nftnl_data_reg_snprintf(buf + offset, remain, &imm->data,
191 flags, DATA_VALUE);
192 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
193
194 } else if (e->flags & (1 << NFTNL_EXPR_IMM_VERDICT)) {
195 ret = nftnl_data_reg_snprintf(buf + offset, remain, &imm->data,
196 flags, DATA_VERDICT);
197 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
198
199 } else if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN)) {
200 ret = nftnl_data_reg_snprintf(buf + offset, remain, &imm->data,
201 flags, DATA_CHAIN);
202 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
203 }
204
205 ret = snprintf(buf + offset, remain, " ");
206 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
207
208 return offset;
209}
210
211static void nftnl_expr_immediate_free(const struct nftnl_expr *e)
212{
213 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
214
215 if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN))
216 xfree(imm->data.chain);
217}
218
219static struct attr_policy immediate_attr_policy[__NFTNL_EXPR_IMM_MAX] = {
220 [NFTNL_EXPR_IMM_DREG] = { .maxlen = sizeof(uint32_t) },
221 [NFTNL_EXPR_IMM_DATA] = { .maxlen = NFT_DATA_VALUE_MAXLEN },
222 [NFTNL_EXPR_IMM_VERDICT] = { .maxlen = sizeof(uint32_t) },
223 [NFTNL_EXPR_IMM_CHAIN] = { .maxlen = NFT_CHAIN_MAXNAMELEN },
224 [NFTNL_EXPR_IMM_CHAIN_ID] = { .maxlen = sizeof(uint32_t) },
225};
226
227struct expr_ops expr_ops_immediate = {
228 .name = "immediate",
229 .alloc_len = sizeof(struct nftnl_expr_immediate),
230 .nftnl_max_attr = __NFTNL_EXPR_IMM_MAX - 1,
231 .attr_policy = immediate_attr_policy,
232 .free = nftnl_expr_immediate_free,
233 .set = nftnl_expr_immediate_set,
234 .get = nftnl_expr_immediate_get,
235 .parse = nftnl_expr_immediate_parse,
236 .build = nftnl_expr_immediate_build,
237 .output = nftnl_expr_immediate_snprintf,
238};
nftnl_expr_immediate
Definition immediate.c:19
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