libnftnl 1.2.9
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
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)
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, data_len);
36 case NFTNL_EXPR_IMM_VERDICT:
37 memcpy(&imm->data.verdict, data, data_len);
38 break;
39 case NFTNL_EXPR_IMM_CHAIN:
40 if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN))
41 xfree(imm->data.chain);
42
43 imm->data.chain = strdup(data);
44 if (!imm->data.chain)
45 return -1;
46 break;
47 case NFTNL_EXPR_IMM_CHAIN_ID:
48 memcpy(&imm->data.chain_id, data, data_len);
49 break;
50 }
51 return 0;
52}
53
54static const void *
55nftnl_expr_immediate_get(const struct nftnl_expr *e, uint16_t type,
56 uint32_t *data_len)
57{
58 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
59
60 switch(type) {
61 case NFTNL_EXPR_IMM_DREG:
62 *data_len = sizeof(imm->dreg);
63 return &imm->dreg;
64 case NFTNL_EXPR_IMM_DATA:
65 *data_len = imm->data.len;
66 return &imm->data.val;
67 case NFTNL_EXPR_IMM_VERDICT:
68 *data_len = sizeof(imm->data.verdict);
69 return &imm->data.verdict;
70 case NFTNL_EXPR_IMM_CHAIN:
71 *data_len = strlen(imm->data.chain)+1;
72 return imm->data.chain;
73 case NFTNL_EXPR_IMM_CHAIN_ID:
74 *data_len = sizeof(imm->data.chain_id);
75 return &imm->data.chain_id;
76 }
77 return NULL;
78}
79
80static int nftnl_expr_immediate_cb(const struct nlattr *attr, void *data)
81{
82 const struct nlattr **tb = data;
83 int type = mnl_attr_get_type(attr);
84
85 if (mnl_attr_type_valid(attr, NFTA_IMMEDIATE_MAX) < 0)
86 return MNL_CB_OK;
87
88 switch(type) {
89 case NFTA_IMMEDIATE_DREG:
90 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
91 abi_breakage();
92 break;
93 case NFTA_IMMEDIATE_DATA:
94 if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0)
95 abi_breakage();
96 break;
97 }
98
99 tb[type] = attr;
100 return MNL_CB_OK;
101}
102
103static void
104nftnl_expr_immediate_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
105{
106 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
107
108 if (e->flags & (1 << NFTNL_EXPR_IMM_DREG))
109 mnl_attr_put_u32(nlh, NFTA_IMMEDIATE_DREG, htonl(imm->dreg));
110
111 /* Sane configurations allows you to set ONLY one of these two below */
112 if (e->flags & (1 << NFTNL_EXPR_IMM_DATA)) {
113 struct nlattr *nest;
114
115 nest = mnl_attr_nest_start(nlh, NFTA_IMMEDIATE_DATA);
116 mnl_attr_put(nlh, NFTA_DATA_VALUE, imm->data.len, imm->data.val);
117 mnl_attr_nest_end(nlh, nest);
118
119 } else if (e->flags & (1 << NFTNL_EXPR_IMM_VERDICT)) {
120 struct nlattr *nest1, *nest2;
121
122 nest1 = mnl_attr_nest_start(nlh, NFTA_IMMEDIATE_DATA);
123 nest2 = mnl_attr_nest_start(nlh, NFTA_DATA_VERDICT);
124 mnl_attr_put_u32(nlh, NFTA_VERDICT_CODE, htonl(imm->data.verdict));
125 if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN))
126 mnl_attr_put_strz(nlh, NFTA_VERDICT_CHAIN, imm->data.chain);
127 if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN_ID)) {
128 mnl_attr_put_u32(nlh, NFTA_VERDICT_CHAIN_ID,
129 htonl(imm->data.chain_id));
130 }
131
132 mnl_attr_nest_end(nlh, nest1);
133 mnl_attr_nest_end(nlh, nest2);
134 }
135}
136
137static int
138nftnl_expr_immediate_parse(struct nftnl_expr *e, struct nlattr *attr)
139{
140 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
141 struct nlattr *tb[NFTA_IMMEDIATE_MAX+1] = {};
142 int ret = 0;
143
144 if (mnl_attr_parse_nested(attr, nftnl_expr_immediate_cb, tb) < 0)
145 return -1;
146
147 if (tb[NFTA_IMMEDIATE_DREG]) {
148 imm->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_IMMEDIATE_DREG]));
149 e->flags |= (1 << NFTNL_EXPR_IMM_DREG);
150 }
151 if (tb[NFTA_IMMEDIATE_DATA]) {
152 int type;
153
154 ret = nftnl_parse_data(&imm->data, tb[NFTA_IMMEDIATE_DATA], &type);
155 if (ret < 0)
156 return ret;
157
158 switch(type) {
159 case DATA_VALUE:
160 /* real immediate data to be loaded to destination */
161 e->flags |= (1 << NFTNL_EXPR_IMM_DATA);
162 break;
163 case DATA_VERDICT:
164 /* NF_ACCEPT, NF_DROP, NF_QUEUE and NFTNL_RETURN case */
165 e->flags |= (1 << NFTNL_EXPR_IMM_VERDICT);
166 break;
167 case DATA_CHAIN:
168 /* NFTNL_GOTO and NFTNL_JUMP case */
169 e->flags |= (1 << NFTNL_EXPR_IMM_VERDICT) |
170 (1 << NFTNL_EXPR_IMM_CHAIN);
171 break;
172 }
173 }
174
175 return ret;
176}
177
178static int
179nftnl_expr_immediate_snprintf(char *buf, size_t remain,
180 uint32_t flags, const struct nftnl_expr *e)
181{
182 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
183 int offset = 0, ret;
184
185 ret = snprintf(buf, remain, "reg %u ", imm->dreg);
186 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
187
188 if (e->flags & (1 << NFTNL_EXPR_IMM_DATA)) {
189 ret = nftnl_data_reg_snprintf(buf + offset, remain, &imm->data,
190 flags, DATA_VALUE);
191 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
192
193 } else if (e->flags & (1 << NFTNL_EXPR_IMM_VERDICT)) {
194 ret = nftnl_data_reg_snprintf(buf + offset, remain, &imm->data,
195 flags, DATA_VERDICT);
196 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
197
198 } else if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN)) {
199 ret = nftnl_data_reg_snprintf(buf + offset, remain, &imm->data,
200 flags, DATA_CHAIN);
201 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
202 }
203
204 return offset;
205}
206
207static void nftnl_expr_immediate_free(const struct nftnl_expr *e)
208{
209 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
210
211 if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN))
212 xfree(imm->data.chain);
213}
214
215static struct attr_policy immediate_attr_policy[__NFTNL_EXPR_IMM_MAX] = {
216 [NFTNL_EXPR_IMM_DREG] = { .maxlen = sizeof(uint32_t) },
217 [NFTNL_EXPR_IMM_DATA] = { .maxlen = NFT_DATA_VALUE_MAXLEN },
218 [NFTNL_EXPR_IMM_VERDICT] = { .maxlen = sizeof(uint32_t) },
219 [NFTNL_EXPR_IMM_CHAIN] = { .maxlen = NFT_CHAIN_MAXNAMELEN },
220 [NFTNL_EXPR_IMM_CHAIN_ID] = { .maxlen = sizeof(uint32_t) },
221};
222
223struct expr_ops expr_ops_immediate = {
224 .name = "immediate",
225 .alloc_len = sizeof(struct nftnl_expr_immediate),
226 .nftnl_max_attr = __NFTNL_EXPR_IMM_MAX - 1,
227 .attr_policy = immediate_attr_policy,
228 .free = nftnl_expr_immediate_free,
229 .set = nftnl_expr_immediate_set,
230 .get = nftnl_expr_immediate_get,
231 .parse = nftnl_expr_immediate_parse,
232 .build = nftnl_expr_immediate_build,
233 .output = nftnl_expr_immediate_snprintf,
234};