libnftnl 1.2.8
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, data_len);
37 break;
38 case NFTNL_EXPR_IMM_DATA:
39 return nftnl_data_cpy(&imm->data, data, data_len);
40 case NFTNL_EXPR_IMM_VERDICT:
41 memcpy(&imm->data.verdict, data, data_len);
42 break;
43 case NFTNL_EXPR_IMM_CHAIN:
44 if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN))
45 xfree(imm->data.chain);
46
47 imm->data.chain = strdup(data);
48 if (!imm->data.chain)
49 return -1;
50 break;
51 case NFTNL_EXPR_IMM_CHAIN_ID:
52 memcpy(&imm->data.chain_id, data, data_len);
53 break;
54 }
55 return 0;
56}
57
58static const void *
59nftnl_expr_immediate_get(const struct nftnl_expr *e, uint16_t type,
60 uint32_t *data_len)
61{
62 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
63
64 switch(type) {
65 case NFTNL_EXPR_IMM_DREG:
66 *data_len = sizeof(imm->dreg);
67 return &imm->dreg;
68 case NFTNL_EXPR_IMM_DATA:
69 *data_len = imm->data.len;
70 return &imm->data.val;
71 case NFTNL_EXPR_IMM_VERDICT:
72 *data_len = sizeof(imm->data.verdict);
73 return &imm->data.verdict;
74 case NFTNL_EXPR_IMM_CHAIN:
75 *data_len = strlen(imm->data.chain)+1;
76 return imm->data.chain;
77 case NFTNL_EXPR_IMM_CHAIN_ID:
78 *data_len = sizeof(imm->data.chain_id);
79 return &imm->data.chain_id;
80 }
81 return NULL;
82}
83
84static int nftnl_expr_immediate_cb(const struct nlattr *attr, void *data)
85{
86 const struct nlattr **tb = data;
87 int type = mnl_attr_get_type(attr);
88
89 if (mnl_attr_type_valid(attr, NFTA_IMMEDIATE_MAX) < 0)
90 return MNL_CB_OK;
91
92 switch(type) {
93 case NFTA_IMMEDIATE_DREG:
94 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
95 abi_breakage();
96 break;
97 case NFTA_IMMEDIATE_DATA:
98 if (mnl_attr_validate(attr, MNL_TYPE_BINARY) < 0)
99 abi_breakage();
100 break;
101 }
102
103 tb[type] = attr;
104 return MNL_CB_OK;
105}
106
107static void
108nftnl_expr_immediate_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
109{
110 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
111
112 if (e->flags & (1 << NFTNL_EXPR_IMM_DREG))
113 mnl_attr_put_u32(nlh, NFTA_IMMEDIATE_DREG, htonl(imm->dreg));
114
115 /* Sane configurations allows you to set ONLY one of these two below */
116 if (e->flags & (1 << NFTNL_EXPR_IMM_DATA)) {
117 struct nlattr *nest;
118
119 nest = mnl_attr_nest_start(nlh, NFTA_IMMEDIATE_DATA);
120 mnl_attr_put(nlh, NFTA_DATA_VALUE, imm->data.len, imm->data.val);
121 mnl_attr_nest_end(nlh, nest);
122
123 } else if (e->flags & (1 << NFTNL_EXPR_IMM_VERDICT)) {
124 struct nlattr *nest1, *nest2;
125
126 nest1 = mnl_attr_nest_start(nlh, NFTA_IMMEDIATE_DATA);
127 nest2 = mnl_attr_nest_start(nlh, NFTA_DATA_VERDICT);
128 mnl_attr_put_u32(nlh, NFTA_VERDICT_CODE, htonl(imm->data.verdict));
129 if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN))
130 mnl_attr_put_strz(nlh, NFTA_VERDICT_CHAIN, imm->data.chain);
131 if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN_ID)) {
132 mnl_attr_put_u32(nlh, NFTA_VERDICT_CHAIN_ID,
133 htonl(imm->data.chain_id));
134 }
135
136 mnl_attr_nest_end(nlh, nest1);
137 mnl_attr_nest_end(nlh, nest2);
138 }
139}
140
141static int
142nftnl_expr_immediate_parse(struct nftnl_expr *e, struct nlattr *attr)
143{
144 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
145 struct nlattr *tb[NFTA_IMMEDIATE_MAX+1] = {};
146 int ret = 0;
147
148 if (mnl_attr_parse_nested(attr, nftnl_expr_immediate_cb, tb) < 0)
149 return -1;
150
151 if (tb[NFTA_IMMEDIATE_DREG]) {
152 imm->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_IMMEDIATE_DREG]));
153 e->flags |= (1 << NFTNL_EXPR_IMM_DREG);
154 }
155 if (tb[NFTA_IMMEDIATE_DATA]) {
156 int type;
157
158 ret = nftnl_parse_data(&imm->data, tb[NFTA_IMMEDIATE_DATA], &type);
159 if (ret < 0)
160 return ret;
161
162 switch(type) {
163 case DATA_VALUE:
164 /* real immediate data to be loaded to destination */
165 e->flags |= (1 << NFTNL_EXPR_IMM_DATA);
166 break;
167 case DATA_VERDICT:
168 /* NF_ACCEPT, NF_DROP, NF_QUEUE and NFTNL_RETURN case */
169 e->flags |= (1 << NFTNL_EXPR_IMM_VERDICT);
170 break;
171 case DATA_CHAIN:
172 /* NFTNL_GOTO and NFTNL_JUMP case */
173 e->flags |= (1 << NFTNL_EXPR_IMM_VERDICT) |
174 (1 << NFTNL_EXPR_IMM_CHAIN);
175 break;
176 }
177 }
178
179 return ret;
180}
181
182static int
183nftnl_expr_immediate_snprintf(char *buf, size_t remain,
184 uint32_t flags, const struct nftnl_expr *e)
185{
186 struct nftnl_expr_immediate *imm = nftnl_expr_data(e);
187 int offset = 0, ret;
188
189 ret = snprintf(buf, remain, "reg %u ", imm->dreg);
190 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
191
192 if (e->flags & (1 << NFTNL_EXPR_IMM_DATA)) {
193 ret = nftnl_data_reg_snprintf(buf + offset, remain, &imm->data,
194 flags, DATA_VALUE);
195 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
196
197 } else if (e->flags & (1 << NFTNL_EXPR_IMM_VERDICT)) {
198 ret = nftnl_data_reg_snprintf(buf + offset, remain, &imm->data,
199 flags, DATA_VERDICT);
200 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
201
202 } else if (e->flags & (1 << NFTNL_EXPR_IMM_CHAIN)) {
203 ret = nftnl_data_reg_snprintf(buf + offset, remain, &imm->data,
204 flags, DATA_CHAIN);
205 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
206 }
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};