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1/*
2 * Copyright (c) 2016 Laura Garcia <nevola@gmail.com>
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 version 2 as
6 * published by the Free Software Foundation.
7 *
8 */
9
10#include <linux/kernel.h>
11#include <linux/init.h>
12#include <linux/module.h>
13#include <linux/netlink.h>
14#include <linux/netfilter.h>
15#include <linux/netfilter/nf_tables.h>
16#include <net/netfilter/nf_tables.h>
17#include <net/netfilter/nf_tables_core.h>
18#include <linux/jhash.h>
19
20struct nft_hash {
21 enum nft_registers sreg:8;
22 enum nft_registers dreg:8;
23 u8 len;
24 u32 modulus;
25 u32 seed;
26 u32 offset;
27};
28
29static void nft_hash_eval(const struct nft_expr *expr,
30 struct nft_regs *regs,
31 const struct nft_pktinfo *pkt)
32{
33 struct nft_hash *priv = nft_expr_priv(expr);
34 const void *data = ®s->data[priv->sreg];
35 u32 h;
36
37 h = reciprocal_scale(jhash(data, priv->len, priv->seed), priv->modulus);
38 regs->data[priv->dreg] = h + priv->offset;
39}
40
41static const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
42 [NFTA_HASH_SREG] = { .type = NLA_U32 },
43 [NFTA_HASH_DREG] = { .type = NLA_U32 },
44 [NFTA_HASH_LEN] = { .type = NLA_U32 },
45 [NFTA_HASH_MODULUS] = { .type = NLA_U32 },
46 [NFTA_HASH_SEED] = { .type = NLA_U32 },
47 [NFTA_HASH_OFFSET] = { .type = NLA_U32 },
48};
49
50static int nft_hash_init(const struct nft_ctx *ctx,
51 const struct nft_expr *expr,
52 const struct nlattr * const tb[])
53{
54 struct nft_hash *priv = nft_expr_priv(expr);
55 u32 len;
56 int err;
57
58 if (!tb[NFTA_HASH_SREG] ||
59 !tb[NFTA_HASH_DREG] ||
60 !tb[NFTA_HASH_LEN] ||
61 !tb[NFTA_HASH_MODULUS])
62 return -EINVAL;
63
64 if (tb[NFTA_HASH_OFFSET])
65 priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET]));
66
67 priv->sreg = nft_parse_register(tb[NFTA_HASH_SREG]);
68 priv->dreg = nft_parse_register(tb[NFTA_HASH_DREG]);
69
70 err = nft_parse_u32_check(tb[NFTA_HASH_LEN], U8_MAX, &len);
71 if (err < 0)
72 return err;
73 if (len == 0)
74 return -ERANGE;
75
76 priv->len = len;
77
78 priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
79 if (priv->modulus <= 1)
80 return -ERANGE;
81
82 if (priv->offset + priv->modulus - 1 < priv->offset)
83 return -EOVERFLOW;
84
85 if (tb[NFTA_HASH_SEED])
86 priv->seed = ntohl(nla_get_be32(tb[NFTA_HASH_SEED]));
87 else
88 get_random_bytes(&priv->seed, sizeof(priv->seed));
89
90 return nft_validate_register_load(priv->sreg, len) &&
91 nft_validate_register_store(ctx, priv->dreg, NULL,
92 NFT_DATA_VALUE, sizeof(u32));
93}
94
95static int nft_hash_dump(struct sk_buff *skb,
96 const struct nft_expr *expr)
97{
98 const struct nft_hash *priv = nft_expr_priv(expr);
99
100 if (nft_dump_register(skb, NFTA_HASH_SREG, priv->sreg))
101 goto nla_put_failure;
102 if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg))
103 goto nla_put_failure;
104 if (nla_put_be32(skb, NFTA_HASH_LEN, htonl(priv->len)))
105 goto nla_put_failure;
106 if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus)))
107 goto nla_put_failure;
108 if (nla_put_be32(skb, NFTA_HASH_SEED, htonl(priv->seed)))
109 goto nla_put_failure;
110 if (priv->offset != 0)
111 if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset)))
112 goto nla_put_failure;
113 return 0;
114
115nla_put_failure:
116 return -1;
117}
118
119static struct nft_expr_type nft_hash_type;
120static const struct nft_expr_ops nft_hash_ops = {
121 .type = &nft_hash_type,
122 .size = NFT_EXPR_SIZE(sizeof(struct nft_hash)),
123 .eval = nft_hash_eval,
124 .init = nft_hash_init,
125 .dump = nft_hash_dump,
126};
127
128static struct nft_expr_type nft_hash_type __read_mostly = {
129 .name = "hash",
130 .ops = &nft_hash_ops,
131 .policy = nft_hash_policy,
132 .maxattr = NFTA_HASH_MAX,
133 .owner = THIS_MODULE,
134};
135
136static int __init nft_hash_module_init(void)
137{
138 return nft_register_expr(&nft_hash_type);
139}
140
141static void __exit nft_hash_module_exit(void)
142{
143 nft_unregister_expr(&nft_hash_type);
144}
145
146module_init(nft_hash_module_init);
147module_exit(nft_hash_module_exit);
148
149MODULE_LICENSE("GPL");
150MODULE_AUTHOR("Laura Garcia <nevola@gmail.com>");
151MODULE_ALIAS_NFT_EXPR("hash");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2016 Laura Garcia <nevola@gmail.com>
4 */
5
6#include <linux/kernel.h>
7#include <linux/init.h>
8#include <linux/module.h>
9#include <linux/netlink.h>
10#include <linux/netfilter.h>
11#include <linux/netfilter/nf_tables.h>
12#include <net/netfilter/nf_tables.h>
13#include <net/netfilter/nf_tables_core.h>
14#include <linux/jhash.h>
15
16struct nft_jhash {
17 u8 sreg;
18 u8 dreg;
19 u8 len;
20 bool autogen_seed:1;
21 u32 modulus;
22 u32 seed;
23 u32 offset;
24};
25
26static void nft_jhash_eval(const struct nft_expr *expr,
27 struct nft_regs *regs,
28 const struct nft_pktinfo *pkt)
29{
30 struct nft_jhash *priv = nft_expr_priv(expr);
31 const void *data = ®s->data[priv->sreg];
32 u32 h;
33
34 h = reciprocal_scale(jhash(data, priv->len, priv->seed),
35 priv->modulus);
36
37 regs->data[priv->dreg] = h + priv->offset;
38}
39
40struct nft_symhash {
41 u8 dreg;
42 u32 modulus;
43 u32 offset;
44};
45
46static void nft_symhash_eval(const struct nft_expr *expr,
47 struct nft_regs *regs,
48 const struct nft_pktinfo *pkt)
49{
50 struct nft_symhash *priv = nft_expr_priv(expr);
51 struct sk_buff *skb = pkt->skb;
52 u32 h;
53
54 h = reciprocal_scale(__skb_get_hash_symmetric(skb), priv->modulus);
55
56 regs->data[priv->dreg] = h + priv->offset;
57}
58
59static const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
60 [NFTA_HASH_SREG] = { .type = NLA_U32 },
61 [NFTA_HASH_DREG] = { .type = NLA_U32 },
62 [NFTA_HASH_LEN] = NLA_POLICY_MAX(NLA_BE32, 255),
63 [NFTA_HASH_MODULUS] = { .type = NLA_U32 },
64 [NFTA_HASH_SEED] = { .type = NLA_U32 },
65 [NFTA_HASH_OFFSET] = { .type = NLA_U32 },
66 [NFTA_HASH_TYPE] = { .type = NLA_U32 },
67};
68
69static int nft_jhash_init(const struct nft_ctx *ctx,
70 const struct nft_expr *expr,
71 const struct nlattr * const tb[])
72{
73 struct nft_jhash *priv = nft_expr_priv(expr);
74 u32 len;
75 int err;
76
77 if (!tb[NFTA_HASH_SREG] ||
78 !tb[NFTA_HASH_DREG] ||
79 !tb[NFTA_HASH_LEN] ||
80 !tb[NFTA_HASH_MODULUS])
81 return -EINVAL;
82
83 if (tb[NFTA_HASH_OFFSET])
84 priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET]));
85
86 err = nft_parse_u32_check(tb[NFTA_HASH_LEN], U8_MAX, &len);
87 if (err < 0)
88 return err;
89 if (len == 0)
90 return -ERANGE;
91
92 priv->len = len;
93
94 err = nft_parse_register_load(tb[NFTA_HASH_SREG], &priv->sreg, len);
95 if (err < 0)
96 return err;
97
98 priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
99 if (priv->modulus < 1)
100 return -ERANGE;
101
102 if (priv->offset + priv->modulus - 1 < priv->offset)
103 return -EOVERFLOW;
104
105 if (tb[NFTA_HASH_SEED]) {
106 priv->seed = ntohl(nla_get_be32(tb[NFTA_HASH_SEED]));
107 } else {
108 priv->autogen_seed = true;
109 get_random_bytes(&priv->seed, sizeof(priv->seed));
110 }
111
112 return nft_parse_register_store(ctx, tb[NFTA_HASH_DREG], &priv->dreg,
113 NULL, NFT_DATA_VALUE, sizeof(u32));
114}
115
116static int nft_symhash_init(const struct nft_ctx *ctx,
117 const struct nft_expr *expr,
118 const struct nlattr * const tb[])
119{
120 struct nft_symhash *priv = nft_expr_priv(expr);
121
122 if (!tb[NFTA_HASH_DREG] ||
123 !tb[NFTA_HASH_MODULUS])
124 return -EINVAL;
125
126 if (tb[NFTA_HASH_OFFSET])
127 priv->offset = ntohl(nla_get_be32(tb[NFTA_HASH_OFFSET]));
128
129 priv->modulus = ntohl(nla_get_be32(tb[NFTA_HASH_MODULUS]));
130 if (priv->modulus < 1)
131 return -ERANGE;
132
133 if (priv->offset + priv->modulus - 1 < priv->offset)
134 return -EOVERFLOW;
135
136 return nft_parse_register_store(ctx, tb[NFTA_HASH_DREG],
137 &priv->dreg, NULL, NFT_DATA_VALUE,
138 sizeof(u32));
139}
140
141static int nft_jhash_dump(struct sk_buff *skb,
142 const struct nft_expr *expr, bool reset)
143{
144 const struct nft_jhash *priv = nft_expr_priv(expr);
145
146 if (nft_dump_register(skb, NFTA_HASH_SREG, priv->sreg))
147 goto nla_put_failure;
148 if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg))
149 goto nla_put_failure;
150 if (nla_put_be32(skb, NFTA_HASH_LEN, htonl(priv->len)))
151 goto nla_put_failure;
152 if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus)))
153 goto nla_put_failure;
154 if (!priv->autogen_seed &&
155 nla_put_be32(skb, NFTA_HASH_SEED, htonl(priv->seed)))
156 goto nla_put_failure;
157 if (priv->offset != 0)
158 if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset)))
159 goto nla_put_failure;
160 if (nla_put_be32(skb, NFTA_HASH_TYPE, htonl(NFT_HASH_JENKINS)))
161 goto nla_put_failure;
162 return 0;
163
164nla_put_failure:
165 return -1;
166}
167
168static bool nft_jhash_reduce(struct nft_regs_track *track,
169 const struct nft_expr *expr)
170{
171 const struct nft_jhash *priv = nft_expr_priv(expr);
172
173 nft_reg_track_cancel(track, priv->dreg, sizeof(u32));
174
175 return false;
176}
177
178static int nft_symhash_dump(struct sk_buff *skb,
179 const struct nft_expr *expr, bool reset)
180{
181 const struct nft_symhash *priv = nft_expr_priv(expr);
182
183 if (nft_dump_register(skb, NFTA_HASH_DREG, priv->dreg))
184 goto nla_put_failure;
185 if (nla_put_be32(skb, NFTA_HASH_MODULUS, htonl(priv->modulus)))
186 goto nla_put_failure;
187 if (priv->offset != 0)
188 if (nla_put_be32(skb, NFTA_HASH_OFFSET, htonl(priv->offset)))
189 goto nla_put_failure;
190 if (nla_put_be32(skb, NFTA_HASH_TYPE, htonl(NFT_HASH_SYM)))
191 goto nla_put_failure;
192 return 0;
193
194nla_put_failure:
195 return -1;
196}
197
198static bool nft_symhash_reduce(struct nft_regs_track *track,
199 const struct nft_expr *expr)
200{
201 struct nft_symhash *priv = nft_expr_priv(expr);
202 struct nft_symhash *symhash;
203
204 if (!nft_reg_track_cmp(track, expr, priv->dreg)) {
205 nft_reg_track_update(track, expr, priv->dreg, sizeof(u32));
206 return false;
207 }
208
209 symhash = nft_expr_priv(track->regs[priv->dreg].selector);
210 if (priv->offset != symhash->offset ||
211 priv->modulus != symhash->modulus) {
212 nft_reg_track_update(track, expr, priv->dreg, sizeof(u32));
213 return false;
214 }
215
216 if (!track->regs[priv->dreg].bitwise)
217 return true;
218
219 return false;
220}
221
222static struct nft_expr_type nft_hash_type;
223static const struct nft_expr_ops nft_jhash_ops = {
224 .type = &nft_hash_type,
225 .size = NFT_EXPR_SIZE(sizeof(struct nft_jhash)),
226 .eval = nft_jhash_eval,
227 .init = nft_jhash_init,
228 .dump = nft_jhash_dump,
229 .reduce = nft_jhash_reduce,
230};
231
232static const struct nft_expr_ops nft_symhash_ops = {
233 .type = &nft_hash_type,
234 .size = NFT_EXPR_SIZE(sizeof(struct nft_symhash)),
235 .eval = nft_symhash_eval,
236 .init = nft_symhash_init,
237 .dump = nft_symhash_dump,
238 .reduce = nft_symhash_reduce,
239};
240
241static const struct nft_expr_ops *
242nft_hash_select_ops(const struct nft_ctx *ctx,
243 const struct nlattr * const tb[])
244{
245 u32 type;
246
247 if (!tb[NFTA_HASH_TYPE])
248 return &nft_jhash_ops;
249
250 type = ntohl(nla_get_be32(tb[NFTA_HASH_TYPE]));
251 switch (type) {
252 case NFT_HASH_SYM:
253 return &nft_symhash_ops;
254 case NFT_HASH_JENKINS:
255 return &nft_jhash_ops;
256 default:
257 break;
258 }
259 return ERR_PTR(-EOPNOTSUPP);
260}
261
262static struct nft_expr_type nft_hash_type __read_mostly = {
263 .name = "hash",
264 .select_ops = nft_hash_select_ops,
265 .policy = nft_hash_policy,
266 .maxattr = NFTA_HASH_MAX,
267 .owner = THIS_MODULE,
268};
269
270static int __init nft_hash_module_init(void)
271{
272 return nft_register_expr(&nft_hash_type);
273}
274
275static void __exit nft_hash_module_exit(void)
276{
277 nft_unregister_expr(&nft_hash_type);
278}
279
280module_init(nft_hash_module_init);
281module_exit(nft_hash_module_exit);
282
283MODULE_LICENSE("GPL");
284MODULE_AUTHOR("Laura Garcia <nevola@gmail.com>");
285MODULE_ALIAS_NFT_EXPR("hash");
286MODULE_DESCRIPTION("Netfilter nftables hash module");