libnftnl 1.2.9
numgen.c
1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 * (C) 2016 by Laura Garcia <nevola@gmail.com>
4 */
5
6#include <stdio.h>
7#include <stdint.h>
8#include <string.h>
9#include <arpa/inet.h>
10#include <errno.h>
11#include <linux/netfilter/nf_tables.h>
12
13#include "internal.h"
14#include <libmnl/libmnl.h>
15#include <libnftnl/expr.h>
16#include <libnftnl/rule.h>
17
19 enum nft_registers dreg;
20 unsigned int modulus;
21 enum nft_ng_types type;
22 unsigned int offset;
23};
24
25static int
26nftnl_expr_ng_set(struct nftnl_expr *e, uint16_t type,
27 const void *data, uint32_t data_len)
28{
29 struct nftnl_expr_ng *ng = nftnl_expr_data(e);
30
31 switch (type) {
32 case NFTNL_EXPR_NG_DREG:
33 memcpy(&ng->dreg, data, data_len);
34 break;
35 case NFTNL_EXPR_NG_MODULUS:
36 memcpy(&ng->modulus, data, data_len);
37 break;
38 case NFTNL_EXPR_NG_TYPE:
39 memcpy(&ng->type, data, data_len);
40 break;
41 case NFTNL_EXPR_NG_OFFSET:
42 memcpy(&ng->offset, data, data_len);
43 break;
44 default:
45 return -1;
46 }
47 return 0;
48}
49
50static const void *
51nftnl_expr_ng_get(const struct nftnl_expr *e, uint16_t type,
52 uint32_t *data_len)
53{
54 struct nftnl_expr_ng *ng = nftnl_expr_data(e);
55
56 switch (type) {
57 case NFTNL_EXPR_NG_DREG:
58 *data_len = sizeof(ng->dreg);
59 return &ng->dreg;
60 case NFTNL_EXPR_NG_MODULUS:
61 *data_len = sizeof(ng->modulus);
62 return &ng->modulus;
63 case NFTNL_EXPR_NG_TYPE:
64 *data_len = sizeof(ng->type);
65 return &ng->type;
66 case NFTNL_EXPR_NG_OFFSET:
67 *data_len = sizeof(ng->offset);
68 return &ng->offset;
69 }
70 return NULL;
71}
72
73static int nftnl_expr_ng_cb(const struct nlattr *attr, void *data)
74{
75 const struct nlattr **tb = data;
76 int type = mnl_attr_get_type(attr);
77
78 if (mnl_attr_type_valid(attr, NFTA_NG_MAX) < 0)
79 return MNL_CB_OK;
80
81 switch (type) {
82 case NFTA_NG_DREG:
83 case NFTA_NG_MODULUS:
84 case NFTA_NG_TYPE:
85 case NFTA_NG_OFFSET:
86 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
87 abi_breakage();
88 break;
89 }
90
91 tb[type] = attr;
92 return MNL_CB_OK;
93}
94
95static void
96nftnl_expr_ng_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
97{
98 struct nftnl_expr_ng *ng = nftnl_expr_data(e);
99
100 if (e->flags & (1 << NFTNL_EXPR_NG_DREG))
101 mnl_attr_put_u32(nlh, NFTA_NG_DREG, htonl(ng->dreg));
102 if (e->flags & (1 << NFTNL_EXPR_NG_MODULUS))
103 mnl_attr_put_u32(nlh, NFTA_NG_MODULUS, htonl(ng->modulus));
104 if (e->flags & (1 << NFTNL_EXPR_NG_TYPE))
105 mnl_attr_put_u32(nlh, NFTA_NG_TYPE, htonl(ng->type));
106 if (e->flags & (1 << NFTNL_EXPR_NG_OFFSET))
107 mnl_attr_put_u32(nlh, NFTA_NG_OFFSET, htonl(ng->offset));
108}
109
110static int
111nftnl_expr_ng_parse(struct nftnl_expr *e, struct nlattr *attr)
112{
113 struct nftnl_expr_ng *ng = nftnl_expr_data(e);
114 struct nlattr *tb[NFTA_NG_MAX+1] = {};
115 int ret = 0;
116
117 if (mnl_attr_parse_nested(attr, nftnl_expr_ng_cb, tb) < 0)
118 return -1;
119
120 if (tb[NFTA_NG_DREG]) {
121 ng->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_NG_DREG]));
122 e->flags |= (1 << NFTNL_EXPR_NG_DREG);
123 }
124 if (tb[NFTA_NG_MODULUS]) {
125 ng->modulus = ntohl(mnl_attr_get_u32(tb[NFTA_NG_MODULUS]));
126 e->flags |= (1 << NFTNL_EXPR_NG_MODULUS);
127 }
128 if (tb[NFTA_NG_TYPE]) {
129 ng->type = ntohl(mnl_attr_get_u32(tb[NFTA_NG_TYPE]));
130 e->flags |= (1 << NFTNL_EXPR_NG_TYPE);
131 }
132 if (tb[NFTA_NG_OFFSET]) {
133 ng->offset = ntohl(mnl_attr_get_u32(tb[NFTA_NG_OFFSET]));
134 e->flags |= (1 << NFTNL_EXPR_NG_OFFSET);
135 }
136
137 return ret;
138}
139
140static int
141nftnl_expr_ng_snprintf(char *buf, size_t remain,
142 uint32_t flags, const struct nftnl_expr *e)
143{
144 struct nftnl_expr_ng *ng = nftnl_expr_data(e);
145 int offset = 0, ret;
146
147 switch (ng->type) {
148 case NFT_NG_INCREMENTAL:
149 ret = snprintf(buf, remain, "reg %u = inc mod %u ",
150 ng->dreg, ng->modulus);
151 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
152 break;
153 case NFT_NG_RANDOM:
154 ret = snprintf(buf, remain, "reg %u = random mod %u ",
155 ng->dreg, ng->modulus);
156 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
157 break;
158 default:
159 return 0;
160 }
161
162 if (ng->offset) {
163 ret = snprintf(buf + offset, remain, "offset %u ", ng->offset);
164 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
165 }
166
167 return offset;
168}
169
170static struct attr_policy numgen_attr_policy[__NFTNL_EXPR_NG_MAX] = {
171 [NFTNL_EXPR_NG_DREG] = { .maxlen = sizeof(uint32_t) },
172 [NFTNL_EXPR_NG_MODULUS] = { .maxlen = sizeof(uint32_t) },
173 [NFTNL_EXPR_NG_TYPE] = { .maxlen = sizeof(uint32_t) },
174 [NFTNL_EXPR_NG_OFFSET] = { .maxlen = sizeof(uint32_t) },
175};
176
177struct expr_ops expr_ops_ng = {
178 .name = "numgen",
179 .alloc_len = sizeof(struct nftnl_expr_ng),
180 .nftnl_max_attr = __NFTNL_EXPR_NG_MAX - 1,
181 .attr_policy = numgen_attr_policy,
182 .set = nftnl_expr_ng_set,
183 .get = nftnl_expr_ng_get,
184 .parse = nftnl_expr_ng_parse,
185 .build = nftnl_expr_ng_build,
186 .output = nftnl_expr_ng_snprintf,
187};