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 
28 static int
29 nftnl_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 
61 static const void *
62 nftnl_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 
93 static 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 
118 static void
119 nftnl_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 
139 static int
140 nftnl_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 
181 static int
182 nftnl_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 
216 static 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 
226 struct 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 };