libnftnl 1.2.7
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, data_len);
41 break;
42 case NFTNL_EXPR_LOOKUP_DREG:
43 memcpy(&lookup->dreg, data, data_len);
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, data_len);
52 break;
53 case NFTNL_EXPR_LOOKUP_FLAGS:
54 memcpy(&lookup->flags, data, data_len);
55 break;
56 }
57 return 0;
58}
59
60static const void *
61nftnl_expr_lookup_get(const struct nftnl_expr *e, uint16_t type,
62 uint32_t *data_len)
63{
64 struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
65
66 switch(type) {
67 case NFTNL_EXPR_LOOKUP_SREG:
68 *data_len = sizeof(lookup->sreg);
69 return &lookup->sreg;
70 case NFTNL_EXPR_LOOKUP_DREG:
71 *data_len = sizeof(lookup->dreg);
72 return &lookup->dreg;
73 case NFTNL_EXPR_LOOKUP_SET:
74 *data_len = strlen(lookup->set_name) + 1;
75 return lookup->set_name;
76 case NFTNL_EXPR_LOOKUP_SET_ID:
77 *data_len = sizeof(lookup->set_id);
78 return &lookup->set_id;
79 case NFTNL_EXPR_LOOKUP_FLAGS:
80 *data_len = sizeof(lookup->flags);
81 return &lookup->flags;
82 }
83 return NULL;
84}
85
86static int nftnl_expr_lookup_cb(const struct nlattr *attr, void *data)
87{
88 const struct nlattr **tb = data;
89 int type = mnl_attr_get_type(attr);
90
91 if (mnl_attr_type_valid(attr, NFTA_LOOKUP_MAX) < 0)
92 return MNL_CB_OK;
93
94 switch(type) {
95 case NFTA_LOOKUP_SREG:
96 case NFTA_LOOKUP_DREG:
97 case NFTA_LOOKUP_SET_ID:
98 case NFTA_LOOKUP_FLAGS:
99 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
100 abi_breakage();
101 break;
102 case NFTA_LOOKUP_SET:
103 if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
104 abi_breakage();
105 break;
106 }
107
108 tb[type] = attr;
109 return MNL_CB_OK;
110}
111
112static void
113nftnl_expr_lookup_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
114{
115 struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
116
117 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_SREG))
118 mnl_attr_put_u32(nlh, NFTA_LOOKUP_SREG, htonl(lookup->sreg));
119 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_DREG))
120 mnl_attr_put_u32(nlh, NFTA_LOOKUP_DREG, htonl(lookup->dreg));
121 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_SET))
122 mnl_attr_put_strz(nlh, NFTA_LOOKUP_SET, lookup->set_name);
123 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_SET_ID))
124 mnl_attr_put_u32(nlh, NFTA_LOOKUP_SET_ID,
125 htonl(lookup->set_id));
126 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_FLAGS))
127 mnl_attr_put_u32(nlh, NFTA_LOOKUP_FLAGS, htonl(lookup->flags));
128}
129
130static int
131nftnl_expr_lookup_parse(struct nftnl_expr *e, struct nlattr *attr)
132{
133 struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
134 struct nlattr *tb[NFTA_LOOKUP_MAX+1] = {};
135 int ret = 0;
136
137 if (mnl_attr_parse_nested(attr, nftnl_expr_lookup_cb, tb) < 0)
138 return -1;
139
140 if (tb[NFTA_LOOKUP_SREG]) {
141 lookup->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_SREG]));
142 e->flags |= (1 << NFTNL_EXPR_LOOKUP_SREG);
143 }
144 if (tb[NFTA_LOOKUP_DREG]) {
145 lookup->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_DREG]));
146 e->flags |= (1 << NFTNL_EXPR_LOOKUP_DREG);
147 }
148 if (tb[NFTA_LOOKUP_SET]) {
149 lookup->set_name =
150 strdup(mnl_attr_get_str(tb[NFTA_LOOKUP_SET]));
151 if (!lookup->set_name)
152 return -1;
153 e->flags |= (1 << NFTNL_EXPR_LOOKUP_SET);
154 }
155 if (tb[NFTA_LOOKUP_SET_ID]) {
156 lookup->set_id =
157 ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_SET_ID]));
158 e->flags |= (1 << NFTNL_EXPR_LOOKUP_SET_ID);
159 }
160 if (tb[NFTA_LOOKUP_FLAGS]) {
161 lookup->flags = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_FLAGS]));
162 e->flags |= (1 << NFTNL_EXPR_LOOKUP_FLAGS);
163 }
164
165 return ret;
166}
167
168static int
169nftnl_expr_lookup_snprintf(char *buf, size_t remain,
170 uint32_t flags, const struct nftnl_expr *e)
171{
172 struct nftnl_expr_lookup *l = nftnl_expr_data(e);
173 int offset = 0, ret;
174
175 ret = snprintf(buf, remain, "reg %u set %s ", l->sreg, l->set_name);
176 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
177
178 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_DREG)) {
179 ret = snprintf(buf + offset, remain, "dreg %u ", l->dreg);
180 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
181 }
182
183 if (e->flags & (1 << NFTNL_EXPR_LOOKUP_FLAGS)) {
184 ret = snprintf(buf + offset, remain, "0x%x ", l->flags);
185 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
186 }
187
188 return offset;
189}
190
191static void nftnl_expr_lookup_free(const struct nftnl_expr *e)
192{
193 struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
194
195 xfree(lookup->set_name);
196}
197
198static struct attr_policy lookup_attr_policy[__NFTNL_EXPR_LOOKUP_MAX] = {
199 [NFTNL_EXPR_LOOKUP_SREG] = { .maxlen = sizeof(uint32_t) },
200 [NFTNL_EXPR_LOOKUP_DREG] = { .maxlen = sizeof(uint32_t) },
201 [NFTNL_EXPR_LOOKUP_SET] = { .maxlen = NFT_SET_MAXNAMELEN },
202 [NFTNL_EXPR_LOOKUP_SET_ID] = { .maxlen = sizeof(uint32_t) },
203 [NFTNL_EXPR_LOOKUP_FLAGS] = { .maxlen = sizeof(uint32_t) },
204};
205
206struct expr_ops expr_ops_lookup = {
207 .name = "lookup",
208 .alloc_len = sizeof(struct nftnl_expr_lookup),
209 .nftnl_max_attr = __NFTNL_EXPR_LOOKUP_MAX - 1,
210 .attr_policy = lookup_attr_policy,
211 .free = nftnl_expr_lookup_free,
212 .set = nftnl_expr_lookup_set,
213 .get = nftnl_expr_lookup_get,
214 .parse = nftnl_expr_lookup_parse,
215 .build = nftnl_expr_lookup_build,
216 .output = nftnl_expr_lookup_snprintf,
217};