libnftnl 1.2.9
hash.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_hash_types type;
20 enum nft_registers sreg;
21 enum nft_registers dreg;
22 unsigned int len;
23 unsigned int modulus;
24 unsigned int seed;
25 unsigned int offset;
26};
27
28static int
29nftnl_expr_hash_set(struct nftnl_expr *e, uint16_t type,
30 const void *data, uint32_t data_len)
31{
32 struct nftnl_expr_hash *hash = nftnl_expr_data(e);
33 switch (type) {
34 case NFTNL_EXPR_HASH_SREG:
35 memcpy(&hash->sreg, data, data_len);
36 break;
37 case NFTNL_EXPR_HASH_DREG:
38 memcpy(&hash->dreg, data, data_len);
39 break;
40 case NFTNL_EXPR_HASH_LEN:
41 memcpy(&hash->len, data, data_len);
42 break;
43 case NFTNL_EXPR_HASH_MODULUS:
44 memcpy(&hash->modulus, data, data_len);
45 break;
46 case NFTNL_EXPR_HASH_SEED:
47 memcpy(&hash->seed, data, data_len);
48 break;
49 case NFTNL_EXPR_HASH_OFFSET:
50 memcpy(&hash->offset, data, data_len);
51 break;
52 case NFTNL_EXPR_HASH_TYPE:
53 memcpy(&hash->type, data, data_len);
54 break;
55 default:
56 return -1;
57 }
58 return 0;
59}
60
61static const void *
62nftnl_expr_hash_get(const struct nftnl_expr *e, uint16_t type,
63 uint32_t *data_len)
64{
65 struct nftnl_expr_hash *hash = nftnl_expr_data(e);
66
67 switch (type) {
68 case NFTNL_EXPR_HASH_SREG:
69 *data_len = sizeof(hash->sreg);
70 return &hash->sreg;
71 case NFTNL_EXPR_HASH_DREG:
72 *data_len = sizeof(hash->dreg);
73 return &hash->dreg;
74 case NFTNL_EXPR_HASH_LEN:
75 *data_len = sizeof(hash->len);
76 return &hash->len;
77 case NFTNL_EXPR_HASH_MODULUS:
78 *data_len = sizeof(hash->modulus);
79 return &hash->modulus;
80 case NFTNL_EXPR_HASH_SEED:
81 *data_len = sizeof(hash->seed);
82 return &hash->seed;
83 case NFTNL_EXPR_HASH_OFFSET:
84 *data_len = sizeof(hash->offset);
85 return &hash->offset;
86 case NFTNL_EXPR_HASH_TYPE:
87 *data_len = sizeof(hash->type);
88 return &hash->type;
89 }
90 return NULL;
91}
92
93static int nftnl_expr_hash_cb(const struct nlattr *attr, void *data)
94{
95 const struct nlattr **tb = data;
96 int type = mnl_attr_get_type(attr);
97
98 if (mnl_attr_type_valid(attr, NFTA_HASH_MAX) < 0)
99 return MNL_CB_OK;
100
101 switch (type) {
102 case NFTA_HASH_SREG:
103 case NFTA_HASH_DREG:
104 case NFTA_HASH_LEN:
105 case NFTA_HASH_MODULUS:
106 case NFTA_HASH_SEED:
107 case NFTA_HASH_OFFSET:
108 case NFTA_HASH_TYPE:
109 if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
110 abi_breakage();
111 break;
112 }
113
114 tb[type] = attr;
115 return MNL_CB_OK;
116}
117
118static void
119nftnl_expr_hash_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
120{
121 struct nftnl_expr_hash *hash = nftnl_expr_data(e);
122
123 if (e->flags & (1 << NFTNL_EXPR_HASH_SREG))
124 mnl_attr_put_u32(nlh, NFTA_HASH_SREG, htonl(hash->sreg));
125 if (e->flags & (1 << NFTNL_EXPR_HASH_DREG))
126 mnl_attr_put_u32(nlh, NFTA_HASH_DREG, htonl(hash->dreg));
127 if (e->flags & (1 << NFTNL_EXPR_HASH_LEN))
128 mnl_attr_put_u32(nlh, NFTA_HASH_LEN, htonl(hash->len));
129 if (e->flags & (1 << NFTNL_EXPR_HASH_MODULUS))
130 mnl_attr_put_u32(nlh, NFTA_HASH_MODULUS, htonl(hash->modulus));
131 if (e->flags & (1 << NFTNL_EXPR_HASH_SEED))
132 mnl_attr_put_u32(nlh, NFTA_HASH_SEED, htonl(hash->seed));
133 if (e->flags & (1 << NFTNL_EXPR_HASH_OFFSET))
134 mnl_attr_put_u32(nlh, NFTA_HASH_OFFSET, htonl(hash->offset));
135 if (e->flags & (1 << NFTNL_EXPR_HASH_TYPE))
136 mnl_attr_put_u32(nlh, NFTA_HASH_TYPE, htonl(hash->type));
137}
138
139static int
140nftnl_expr_hash_parse(struct nftnl_expr *e, struct nlattr *attr)
141{
142 struct nftnl_expr_hash *hash = nftnl_expr_data(e);
143 struct nlattr *tb[NFTA_HASH_MAX+1] = {};
144 int ret = 0;
145
146 if (mnl_attr_parse_nested(attr, nftnl_expr_hash_cb, tb) < 0)
147 return -1;
148
149 if (tb[NFTA_HASH_SREG]) {
150 hash->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_SREG]));
151 e->flags |= (1 << NFTNL_EXPR_HASH_SREG);
152 }
153 if (tb[NFTA_HASH_DREG]) {
154 hash->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_DREG]));
155 e->flags |= (1 << NFTNL_EXPR_HASH_DREG);
156 }
157 if (tb[NFTA_HASH_LEN]) {
158 hash->len = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_LEN]));
159 e->flags |= (1 << NFTNL_EXPR_HASH_LEN);
160 }
161 if (tb[NFTA_HASH_MODULUS]) {
162 hash->modulus = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_MODULUS]));
163 e->flags |= (1 << NFTNL_EXPR_HASH_MODULUS);
164 }
165 if (tb[NFTA_HASH_SEED]) {
166 hash->seed = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_SEED]));
167 e->flags |= (1 << NFTNL_EXPR_HASH_SEED);
168 }
169 if (tb[NFTA_HASH_OFFSET]) {
170 hash->offset = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_OFFSET]));
171 e->flags |= (1 << NFTNL_EXPR_HASH_OFFSET);
172 }
173 if (tb[NFTA_HASH_TYPE]) {
174 hash->type = ntohl(mnl_attr_get_u32(tb[NFTA_HASH_TYPE]));
175 e->flags |= (1 << NFTNL_EXPR_HASH_TYPE);
176 }
177
178 return ret;
179}
180
181static int
182nftnl_expr_hash_snprintf(char *buf, size_t remain,
183 uint32_t flags, const struct nftnl_expr *e)
184{
185 struct nftnl_expr_hash *hash = nftnl_expr_data(e);
186 int offset = 0, ret;
187
188 switch (hash->type) {
189 case NFT_HASH_SYM:
190 ret =
191 snprintf(buf, remain, "reg %u = symhash() %% mod %u ",
192 hash->dreg,
193 hash->modulus);
194 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
195 break;
196 case NFT_HASH_JENKINS:
197 default:
198 ret =
199 snprintf(buf, remain,
200 "reg %u = jhash(reg %u, %u, 0x%x) %% mod %u ",
201 hash->dreg, hash->sreg, hash->len, hash->seed,
202 hash->modulus);
203 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
204 break;
205 }
206
207 if (hash->offset) {
208 ret = snprintf(buf + offset, remain, "offset %u ",
209 hash->offset);
210 SNPRINTF_BUFFER_SIZE(ret, remain, offset);
211 }
212
213 return offset;
214}
215
216static struct attr_policy hash_attr_policy[__NFTNL_EXPR_HASH_MAX] = {
217 [NFTNL_EXPR_HASH_SREG] = { .maxlen = sizeof(uint32_t) },
218 [NFTNL_EXPR_HASH_DREG] = { .maxlen = sizeof(uint32_t) },
219 [NFTNL_EXPR_HASH_LEN] = { .maxlen = sizeof(uint32_t) },
220 [NFTNL_EXPR_HASH_MODULUS] = { .maxlen = sizeof(uint32_t) },
221 [NFTNL_EXPR_HASH_SEED] = { .maxlen = sizeof(uint32_t) },
222 [NFTNL_EXPR_HASH_OFFSET] = { .maxlen = sizeof(uint32_t) },
223 [NFTNL_EXPR_HASH_TYPE] = { .maxlen = sizeof(uint32_t) },
224};
225
226struct expr_ops expr_ops_hash = {
227 .name = "hash",
228 .alloc_len = sizeof(struct nftnl_expr_hash),
229 .nftnl_max_attr = __NFTNL_EXPR_HASH_MAX - 1,
230 .attr_policy = hash_attr_policy,
231 .set = nftnl_expr_hash_set,
232 .get = nftnl_expr_hash_get,
233 .parse = nftnl_expr_hash_parse,
234 .build = nftnl_expr_hash_build,
235 .output = nftnl_expr_hash_snprintf,
236};