libnftnl 1.2.6
immediate.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 <stdio.h>
13#include <stdint.h>
14#include <string.h>
15#include <arpa/inet.h>
16#include <errno.h>
17#include "internal.h"
18#include <libmnl/libmnl.h>
19#include <linux/netfilter/nf_tables.h>
20#include <libnftnl/expr.h>
21#include <libnftnl/rule.h>
22
24 union nftnl_data_reg data;
25 enum nft_registers dreg;
26};
27
28static int
29nftnl_expr_immediate_set(struct nftnl_expr *e, uint16_t type,
30 const void *data, uint32_t data_len)
31{
32 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
33
34 switch(type) {
35 case NFTNL_EXPR_IMM_DREG:
36 memcpy(&imm->dreg, data, sizeof(imm->dreg));
37 break;
38 case NFTNL_EXPR_IMM_DATA:
39 memcpy(&imm->data.val, data, data_len);
40 imm->data.len = data_len;
41 break;
42 case NFTNL_EXPR_IMM_VERDICT:
43 memcpy(&imm->data.verdict, data, sizeof(imm->data.verdict));
44 break;
45 case NFTNL_EXPR_IMM_CHAIN:
46 if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN))
47 xfree(imm->data.chain);
48
49 imm->data.chain = strdup(data);
50 if (!imm->data.chain)
51 return -1;
52 break;
53 case NFTNL_EXPR_IMM_CHAIN_ID:
54 memcpy(&imm->data.chain_id, data, sizeof(uint32_t));
55 break;
56 default:
57 return -1;
58 }
59 return 0;
60}
61
62static const void *
63nftnl_expr_immediate_get(const struct nftnl_expr *e, uint16_t type,
64 uint32_t *data_len)
65{
66 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
67
68 switch(type) {
69 case NFTNL_EXPR_IMM_DREG:
70 *data_len = sizeof(imm->dreg);
71 return &imm->dreg;
72 case NFTNL_EXPR_IMM_DATA:
73 *data_len = imm->data.len;
74 return &imm->data.val;
75 case NFTNL_EXPR_IMM_VERDICT:
76 *data_len = sizeof(imm->data.verdict);
77 return &imm->data.verdict;
78 case NFTNL_EXPR_IMM_CHAIN:
79 *data_len = strlen(imm->data.chain)+1;
80 return imm->data.chain;
81 case NFTNL_EXPR_IMM_CHAIN_ID:
82 *data_len = sizeof(imm->data.chain_id);
83 return &imm->data.chain_id;
84 }
85 return NULL;
86}
87
88static int nftnl_expr_immediate_cb(const struct nlattr *attr, void *data)
89{
90 const struct nlattr **tb = data;
91 int type = mnl_attr_get_type(attr);
92
93 if (mnl_attr_type_valid(attr, NFTA_IMMEDIATE_MAX) < 0)
94 return MNL_CB_OK;
95
96 switch(type) {
97 case NFTA_IMMEDIATE_DREG:
98 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
99 abi_breakage();
100 break;
101 case NFTA_IMMEDIATE_DATA:
102 if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0)
103 abi_breakage();
104 break;
105 }
106
107 tb[type] = attr;
108 return MNL_CB_OK;
109}
110
111static void
112nftnl_expr_immediate_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
113{
114 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
115
116 if (e->flags & (1 << NFTNL_EXPR_IMM_DREG))
117 mnl_attr_put_u32(nlh, NFTA_IMMEDIATE_DREG, htonl(imm->dreg));
118
119 /* Sane configurations allows you to set ONLY one of these two below */
120 if (e->flags & (1 << NFTNL_EXPR_IMM_DATA)) {
121 struct nlattr *nest;
122
123 nest = mnl_attr_nest_start(nlh, NFTA_IMMEDIATE_DATA);
124 mnl_attr_put(nlh, NFTA_DATA_VALUE, imm->data.len, imm->data.val);
125 mnl_attr_nest_end(nlh, nest);
126
127 } else if (e->flags & (1 << NFTNL_EXPR_IMM_VERDICT)) {
128 struct nlattr *nest1, *nest2;
129
130 nest1 = mnl_attr_nest_start(nlh, NFTA_IMMEDIATE_DATA);
131 nest2 = mnl_attr_nest_start(nlh, NFTA_DATA_VERDICT);
132 mnl_attr_put_u32(nlh, NFTA_VERDICT_CODE, htonl(imm->data.verdict));
133 if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN))
134 mnl_attr_put_strz(nlh, NFTA_VERDICT_CHAIN, imm->data.chain);
135 if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN_ID)) {
136 mnl_attr_put_u32(nlh, NFTA_VERDICT_CHAIN_ID,
137 htonl(imm->data.chain_id));
138 }
139
140 mnl_attr_nest_end(nlh, nest1);
141 mnl_attr_nest_end(nlh, nest2);
142 }
143}
144
145static int
146nftnl_expr_immediate_parse(struct nftnl_expr *e, struct nlattr *attr)
147{
148 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
149 struct nlattr *tb[NFTA_IMMEDIATE_MAX+1] = {};
150 int ret = 0;
151
152 if (mnl_attr_parse_nested(attr, nftnl_expr_immediate_cb, tb) < 0)
153 return -1;
154
155 if (tb[NFTA_IMMEDIATE_DREG]) {
156 imm->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_IMMEDIATE_DREG]));
157 e->flags |= (1 << NFTNL_EXPR_IMM_DREG);
158 }
159 if (tb[NFTA_IMMEDIATE_DATA]) {
160 int type;
161
162 ret = nftnl_parse_data(&imm->data, tb[NFTA_IMMEDIATE_DATA], &type);
163 if (ret < 0)
164 return ret;
165
166 switch(type) {
167 case DATA_VALUE:
168 /* real immediate data to be loaded to destination */
169 e->flags |= (1 << NFTNL_EXPR_IMM_DATA);
170 break;
171 case DATA_VERDICT:
172 /* NF_ACCEPT, NF_DROP, NF_QUEUE and NFTNL_RETURN case */
173 e->flags |= (1 << NFTNL_EXPR_IMM_VERDICT);
174 break;
175 case DATA_CHAIN:
176 /* NFTNL_GOTO and NFTNL_JUMP case */
177 e->flags |= (1 << NFTNL_EXPR_IMM_VERDICT) |
178 (1 << NFTNL_EXPR_IMM_CHAIN);
179 break;
180 }
181 }
182
183 return ret;
184}
185
186static int
187nftnl_expr_immediate_snprintf(char *buf, size_t remain,
188 uint32_t flags, const struct nftnl_expr *e)
189{
190 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
191 int offset = 0, ret;
192
193 ret = snprintf(buf, remain, "reg %u ", imm->dreg);
194 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
195
196 if (e->flags & (1 << NFTNL_EXPR_IMM_DATA)) {
197 ret = nftnl_data_reg_snprintf(buf + offset, remain, &imm->data,
198 flags, DATA_VALUE);
199 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
200
201 } else if (e->flags & (1 << NFTNL_EXPR_IMM_VERDICT)) {
202 ret = nftnl_data_reg_snprintf(buf + offset, remain, &imm->data,
203 flags, DATA_VERDICT);
204 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
205
206 } else if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN)) {
207 ret = nftnl_data_reg_snprintf(buf + offset, remain, &imm->data,
208 flags, DATA_CHAIN);
209 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
210 }
211
212 return offset;
213}
214
215static void nftnl_expr_immediate_free(const struct nftnl_expr *e)
216{
217 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
218
219 if (e->flags & (1 << NFTNL_EXPR_IMM_VERDICT))
220 nftnl_free_verdict(&imm->data);
221}
222
223struct expr_ops expr_ops_immediate = {
224 .name = "immediate",
225 .alloc_len = sizeof(struct nftnl_expr_immediate),
226 .max_attr = NFTA_IMMEDIATE_MAX,
227 .free = nftnl_expr_immediate_free,
228 .set = nftnl_expr_immediate_set,
229 .get = nftnl_expr_immediate_get,
230 .parse = nftnl_expr_immediate_parse,
231 .build = nftnl_expr_immediate_build,
232 .output = nftnl_expr_immediate_snprintf,
233};