libnftnl 1.2.6
lookup.c
1/*
2 * (C) 2012-2013 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 "internal.h"
13
14#include <stdio.h>
15#include <stdint.h>
16#include <string.h> /* for memcpy */
17#include <arpa/inet.h>
18#include <errno.h>
19#include <libmnl/libmnl.h>
20#include <linux/netfilter/nf_tables.h>
21#include <libnftnl/rule.h>
22#include <libnftnl/expr.h>
23
25 enum nft_registers sreg;
26 enum nft_registers dreg;
27 char *set_name;
28 uint32_t set_id;
29 uint32_t flags;
30};
31
32static int
33nftnl_expr_lookup_set(struct nftnl_expr *e, uint16_t type,
34 const void *data, uint32_t data_len)
35{
36 struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
37
38 switch(type) {
39 case NFTNL_EXPR_LOOKUP_SREG:
40 memcpy(&lookup->sreg, data, sizeof(lookup->sreg));
41 break;
42 case NFTNL_EXPR_LOOKUP_DREG:
43 memcpy(&lookup->dreg, data, sizeof(lookup->dreg));
44 break;
45 case NFTNL_EXPR_LOOKUP_SET:
46 lookup->set_name = strdup((const char *)data);
47 if (!lookup->set_name)
48 return -1;
49 break;
50 case NFTNL_EXPR_LOOKUP_SET_ID:
51 memcpy(&lookup->set_id, data, sizeof(lookup->set_id));
52 break;
53 case NFTNL_EXPR_LOOKUP_FLAGS:
54 memcpy(&lookup->flags, data, sizeof(lookup->flags));
55 break;
56 default:
57 return -1;
58 }
59 return 0;
60}
61
62static const void *
63nftnl_expr_lookup_get(const struct nftnl_expr *e, uint16_t type,
64 uint32_t *data_len)
65{
66 struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
67
68 switch(type) {
69 case NFTNL_EXPR_LOOKUP_SREG:
70 *data_len = sizeof(lookup->sreg);
71 return &lookup->sreg;
72 case NFTNL_EXPR_LOOKUP_DREG:
73 *data_len = sizeof(lookup->dreg);
74 return &lookup->dreg;
75 case NFTNL_EXPR_LOOKUP_SET:
76 *data_len = strlen(lookup->set_name) + 1;
77 return lookup->set_name;
78 case NFTNL_EXPR_LOOKUP_SET_ID:
79 *data_len = sizeof(lookup->set_id);
80 return &lookup->set_id;
81 case NFTNL_EXPR_LOOKUP_FLAGS:
82 *data_len = sizeof(lookup->flags);
83 return &lookup->flags;
84 }
85 return NULL;
86}
87
88static int nftnl_expr_lookup_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_LOOKUP_MAX) < 0)
94 return MNL_CB_OK;
95
96 switch(type) {
97 case NFTA_LOOKUP_SREG:
98 case NFTA_LOOKUP_DREG:
99 case NFTA_LOOKUP_SET_ID:
100 case NFTA_LOOKUP_FLAGS:
101 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
102 abi_breakage();
103 break;
104 case NFTA_LOOKUP_SET:
105 if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
106 abi_breakage();
107 break;
108 }
109
110 tb[type] = attr;
111 return MNL_CB_OK;
112}
113
114static void
115nftnl_expr_lookup_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
116{
117 struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
118
119 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_SREG))
120 mnl_attr_put_u32(nlh, NFTA_LOOKUP_SREG, htonl(lookup->sreg));
121 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_DREG))
122 mnl_attr_put_u32(nlh, NFTA_LOOKUP_DREG, htonl(lookup->dreg));
123 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_SET))
124 mnl_attr_put_strz(nlh, NFTA_LOOKUP_SET, lookup->set_name);
125 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_SET_ID))
126 mnl_attr_put_u32(nlh, NFTA_LOOKUP_SET_ID,
127 htonl(lookup->set_id));
128 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_FLAGS))
129 mnl_attr_put_u32(nlh, NFTA_LOOKUP_FLAGS, htonl(lookup->flags));
130}
131
132static int
133nftnl_expr_lookup_parse(struct nftnl_expr *e, struct nlattr *attr)
134{
135 struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
136 struct nlattr *tb[NFTA_LOOKUP_MAX+1] = {};
137 int ret = 0;
138
139 if (mnl_attr_parse_nested(attr, nftnl_expr_lookup_cb, tb) < 0)
140 return -1;
141
142 if (tb[NFTA_LOOKUP_SREG]) {
143 lookup->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_SREG]));
144 e->flags |= (1 << NFTNL_EXPR_LOOKUP_SREG);
145 }
146 if (tb[NFTA_LOOKUP_DREG]) {
147 lookup->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_DREG]));
148 e->flags |= (1 << NFTNL_EXPR_LOOKUP_DREG);
149 }
150 if (tb[NFTA_LOOKUP_SET]) {
151 lookup->set_name =
152 strdup(mnl_attr_get_str(tb[NFTA_LOOKUP_SET]));
153 if (!lookup->set_name)
154 return -1;
155 e->flags |= (1 << NFTNL_EXPR_LOOKUP_SET);
156 }
157 if (tb[NFTA_LOOKUP_SET_ID]) {
158 lookup->set_id =
159 ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_SET_ID]));
160 e->flags |= (1 << NFTNL_EXPR_LOOKUP_SET_ID);
161 }
162 if (tb[NFTA_LOOKUP_FLAGS]) {
163 lookup->flags = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_FLAGS]));
164 e->flags |= (1 << NFTNL_EXPR_LOOKUP_FLAGS);
165 }
166
167 return ret;
168}
169
170static int
171nftnl_expr_lookup_snprintf(char *buf, size_t remain,
172 uint32_t flags, const struct nftnl_expr *e)
173{
174 struct nftnl_expr_lookup *l = nftnl_expr_data(e);
175 int offset = 0, ret;
176
177 ret = snprintf(buf, remain, "reg %u set %s ", l->sreg, l->set_name);
178 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
179
180 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_DREG)) {
181 ret = snprintf(buf + offset, remain, "dreg %u ", l->dreg);
182 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
183 }
184
185 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_FLAGS)) {
186 ret = snprintf(buf + offset, remain, "0x%x ", l->flags);
187 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
188 }
189
190 return offset;
191}
192
193static void nftnl_expr_lookup_free(const struct nftnl_expr *e)
194{
195 struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
196
197 xfree(lookup->set_name);
198}
199
200struct expr_ops expr_ops_lookup = {
201 .name = "lookup",
202 .alloc_len = sizeof(struct nftnl_expr_lookup),
203 .max_attr = NFTA_LOOKUP_MAX,
204 .free = nftnl_expr_lookup_free,
205 .set = nftnl_expr_lookup_set,
206 .get = nftnl_expr_lookup_get,
207 .parse = nftnl_expr_lookup_parse,
208 .build = nftnl_expr_lookup_build,
209 .output = nftnl_expr_lookup_snprintf,
210};