libnftnl  1.2.9
lookup.c
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * (C) 2012-2013 by Pablo Neira Ayuso <pablo@netfilter.org>
4  *
5  * This code has been sponsored by Sophos Astaro <http://www.sophos.com>
6  */
7 
8 #include "internal.h"
9 
10 #include <stdio.h>
11 #include <stdint.h>
12 #include <string.h> /* for memcpy */
13 #include <arpa/inet.h>
14 #include <errno.h>
15 #include <libmnl/libmnl.h>
16 #include <linux/netfilter/nf_tables.h>
17 #include <libnftnl/rule.h>
18 #include <libnftnl/expr.h>
19 
21  enum nft_registers sreg;
22  enum nft_registers dreg;
23  char *set_name;
24  uint32_t set_id;
25  uint32_t flags;
26 };
27 
28 static int
29 nftnl_expr_lookup_set(struct nftnl_expr *e, uint16_t type,
30  const void *data, uint32_t data_len)
31 {
32  struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
33 
34  switch(type) {
35  case NFTNL_EXPR_LOOKUP_SREG:
36  memcpy(&lookup->sreg, data, data_len);
37  break;
38  case NFTNL_EXPR_LOOKUP_DREG:
39  memcpy(&lookup->dreg, data, data_len);
40  break;
41  case NFTNL_EXPR_LOOKUP_SET:
42  lookup->set_name = strdup((const char *)data);
43  if (!lookup->set_name)
44  return -1;
45  break;
46  case NFTNL_EXPR_LOOKUP_SET_ID:
47  memcpy(&lookup->set_id, data, data_len);
48  break;
49  case NFTNL_EXPR_LOOKUP_FLAGS:
50  memcpy(&lookup->flags, data, data_len);
51  break;
52  }
53  return 0;
54 }
55 
56 static const void *
57 nftnl_expr_lookup_get(const struct nftnl_expr *e, uint16_t type,
58  uint32_t *data_len)
59 {
60  struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
61 
62  switch(type) {
63  case NFTNL_EXPR_LOOKUP_SREG:
64  *data_len = sizeof(lookup->sreg);
65  return &lookup->sreg;
66  case NFTNL_EXPR_LOOKUP_DREG:
67  *data_len = sizeof(lookup->dreg);
68  return &lookup->dreg;
69  case NFTNL_EXPR_LOOKUP_SET:
70  *data_len = strlen(lookup->set_name) + 1;
71  return lookup->set_name;
72  case NFTNL_EXPR_LOOKUP_SET_ID:
73  *data_len = sizeof(lookup->set_id);
74  return &lookup->set_id;
75  case NFTNL_EXPR_LOOKUP_FLAGS:
76  *data_len = sizeof(lookup->flags);
77  return &lookup->flags;
78  }
79  return NULL;
80 }
81 
82 static int nftnl_expr_lookup_cb(const struct nlattr *attr, void *data)
83 {
84  const struct nlattr **tb = data;
85  int type = mnl_attr_get_type(attr);
86 
87  if (mnl_attr_type_valid(attr, NFTA_LOOKUP_MAX) < 0)
88  return MNL_CB_OK;
89 
90  switch(type) {
91  case NFTA_LOOKUP_SREG:
92  case NFTA_LOOKUP_DREG:
93  case NFTA_LOOKUP_SET_ID:
94  case NFTA_LOOKUP_FLAGS:
95  if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
96  abi_breakage();
97  break;
98  case NFTA_LOOKUP_SET:
99  if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
100  abi_breakage();
101  break;
102  }
103 
104  tb[type] = attr;
105  return MNL_CB_OK;
106 }
107 
108 static void
109 nftnl_expr_lookup_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
110 {
111  struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
112 
113  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_SREG))
114  mnl_attr_put_u32(nlh, NFTA_LOOKUP_SREG, htonl(lookup->sreg));
115  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_DREG))
116  mnl_attr_put_u32(nlh, NFTA_LOOKUP_DREG, htonl(lookup->dreg));
117  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_SET))
118  mnl_attr_put_strz(nlh, NFTA_LOOKUP_SET, lookup->set_name);
119  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_SET_ID))
120  mnl_attr_put_u32(nlh, NFTA_LOOKUP_SET_ID,
121  htonl(lookup->set_id));
122  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_FLAGS))
123  mnl_attr_put_u32(nlh, NFTA_LOOKUP_FLAGS, htonl(lookup->flags));
124 }
125 
126 static int
127 nftnl_expr_lookup_parse(struct nftnl_expr *e, struct nlattr *attr)
128 {
129  struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
130  struct nlattr *tb[NFTA_LOOKUP_MAX+1] = {};
131  int ret = 0;
132 
133  if (mnl_attr_parse_nested(attr, nftnl_expr_lookup_cb, tb) < 0)
134  return -1;
135 
136  if (tb[NFTA_LOOKUP_SREG]) {
137  lookup->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_SREG]));
138  e->flags |= (1 << NFTNL_EXPR_LOOKUP_SREG);
139  }
140  if (tb[NFTA_LOOKUP_DREG]) {
141  lookup->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_DREG]));
142  e->flags |= (1 << NFTNL_EXPR_LOOKUP_DREG);
143  }
144  if (tb[NFTA_LOOKUP_SET]) {
145  lookup->set_name =
146  strdup(mnl_attr_get_str(tb[NFTA_LOOKUP_SET]));
147  if (!lookup->set_name)
148  return -1;
149  e->flags |= (1 << NFTNL_EXPR_LOOKUP_SET);
150  }
151  if (tb[NFTA_LOOKUP_SET_ID]) {
152  lookup->set_id =
153  ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_SET_ID]));
154  e->flags |= (1 << NFTNL_EXPR_LOOKUP_SET_ID);
155  }
156  if (tb[NFTA_LOOKUP_FLAGS]) {
157  lookup->flags = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_FLAGS]));
158  e->flags |= (1 << NFTNL_EXPR_LOOKUP_FLAGS);
159  }
160 
161  return ret;
162 }
163 
164 static int
165 nftnl_expr_lookup_snprintf(char *buf, size_t remain,
166  uint32_t flags, const struct nftnl_expr *e)
167 {
168  struct nftnl_expr_lookup *l = nftnl_expr_data(e);
169  int offset = 0, ret;
170 
171  ret = snprintf(buf, remain, "reg %u set %s ", l->sreg, l->set_name);
172  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
173 
174  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_DREG)) {
175  ret = snprintf(buf + offset, remain, "dreg %u ", l->dreg);
176  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
177  }
178 
179  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_FLAGS)) {
180  ret = snprintf(buf + offset, remain, "0x%x ", l->flags);
181  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
182  }
183 
184  return offset;
185 }
186 
187 static void nftnl_expr_lookup_free(const struct nftnl_expr *e)
188 {
189  struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
190 
191  xfree(lookup->set_name);
192 }
193 
194 static struct attr_policy lookup_attr_policy[__NFTNL_EXPR_LOOKUP_MAX] = {
195  [NFTNL_EXPR_LOOKUP_SREG] = { .maxlen = sizeof(uint32_t) },
196  [NFTNL_EXPR_LOOKUP_DREG] = { .maxlen = sizeof(uint32_t) },
197  [NFTNL_EXPR_LOOKUP_SET] = { .maxlen = NFT_SET_MAXNAMELEN },
198  [NFTNL_EXPR_LOOKUP_SET_ID] = { .maxlen = sizeof(uint32_t) },
199  [NFTNL_EXPR_LOOKUP_FLAGS] = { .maxlen = sizeof(uint32_t) },
200 };
201 
202 struct expr_ops expr_ops_lookup = {
203  .name = "lookup",
204  .alloc_len = sizeof(struct nftnl_expr_lookup),
205  .nftnl_max_attr = __NFTNL_EXPR_LOOKUP_MAX - 1,
206  .attr_policy = lookup_attr_policy,
207  .free = nftnl_expr_lookup_free,
208  .set = nftnl_expr_lookup_set,
209  .get = nftnl_expr_lookup_get,
210  .parse = nftnl_expr_lookup_parse,
211  .build = nftnl_expr_lookup_build,
212  .output = nftnl_expr_lookup_snprintf,
213 };