libnftnl  1.2.8
lookup.c
1 /*
2  * (C) 2012-2013 by Pablo Neira Ayuso <pablo@netfilter.org>
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 as published
6  * by the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This code has been sponsored by Sophos Astaro <http://www.sophos.com>
10  */
11 
12 #include "internal.h"
13 
14 #include <stdio.h>
15 #include <stdint.h>
16 #include <string.h> /* for memcpy */
17 #include <arpa/inet.h>
18 #include <errno.h>
19 #include <libmnl/libmnl.h>
20 #include <linux/netfilter/nf_tables.h>
21 #include <libnftnl/rule.h>
22 #include <libnftnl/expr.h>
23 
25  enum nft_registers sreg;
26  enum nft_registers dreg;
27  char *set_name;
28  uint32_t set_id;
29  uint32_t flags;
30 };
31 
32 static int
33 nftnl_expr_lookup_set(struct nftnl_expr *e, uint16_t type,
34  const void *data, uint32_t data_len)
35 {
36  struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
37 
38  switch(type) {
39  case NFTNL_EXPR_LOOKUP_SREG:
40  memcpy(&lookup->sreg, data, data_len);
41  break;
42  case NFTNL_EXPR_LOOKUP_DREG:
43  memcpy(&lookup->dreg, data, data_len);
44  break;
45  case NFTNL_EXPR_LOOKUP_SET:
46  lookup->set_name = strdup((const char *)data);
47  if (!lookup->set_name)
48  return -1;
49  break;
50  case NFTNL_EXPR_LOOKUP_SET_ID:
51  memcpy(&lookup->set_id, data, data_len);
52  break;
53  case NFTNL_EXPR_LOOKUP_FLAGS:
54  memcpy(&lookup->flags, data, data_len);
55  break;
56  }
57  return 0;
58 }
59 
60 static const void *
61 nftnl_expr_lookup_get(const struct nftnl_expr *e, uint16_t type,
62  uint32_t *data_len)
63 {
64  struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
65 
66  switch(type) {
67  case NFTNL_EXPR_LOOKUP_SREG:
68  *data_len = sizeof(lookup->sreg);
69  return &lookup->sreg;
70  case NFTNL_EXPR_LOOKUP_DREG:
71  *data_len = sizeof(lookup->dreg);
72  return &lookup->dreg;
73  case NFTNL_EXPR_LOOKUP_SET:
74  *data_len = strlen(lookup->set_name) + 1;
75  return lookup->set_name;
76  case NFTNL_EXPR_LOOKUP_SET_ID:
77  *data_len = sizeof(lookup->set_id);
78  return &lookup->set_id;
79  case NFTNL_EXPR_LOOKUP_FLAGS:
80  *data_len = sizeof(lookup->flags);
81  return &lookup->flags;
82  }
83  return NULL;
84 }
85 
86 static int nftnl_expr_lookup_cb(const struct nlattr *attr, void *data)
87 {
88  const struct nlattr **tb = data;
89  int type = mnl_attr_get_type(attr);
90 
91  if (mnl_attr_type_valid(attr, NFTA_LOOKUP_MAX) < 0)
92  return MNL_CB_OK;
93 
94  switch(type) {
95  case NFTA_LOOKUP_SREG:
96  case NFTA_LOOKUP_DREG:
97  case NFTA_LOOKUP_SET_ID:
98  case NFTA_LOOKUP_FLAGS:
99  if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
100  abi_breakage();
101  break;
102  case NFTA_LOOKUP_SET:
103  if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
104  abi_breakage();
105  break;
106  }
107 
108  tb[type] = attr;
109  return MNL_CB_OK;
110 }
111 
112 static void
113 nftnl_expr_lookup_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
114 {
115  struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
116 
117  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_SREG))
118  mnl_attr_put_u32(nlh, NFTA_LOOKUP_SREG, htonl(lookup->sreg));
119  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_DREG))
120  mnl_attr_put_u32(nlh, NFTA_LOOKUP_DREG, htonl(lookup->dreg));
121  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_SET))
122  mnl_attr_put_strz(nlh, NFTA_LOOKUP_SET, lookup->set_name);
123  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_SET_ID))
124  mnl_attr_put_u32(nlh, NFTA_LOOKUP_SET_ID,
125  htonl(lookup->set_id));
126  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_FLAGS))
127  mnl_attr_put_u32(nlh, NFTA_LOOKUP_FLAGS, htonl(lookup->flags));
128 }
129 
130 static int
131 nftnl_expr_lookup_parse(struct nftnl_expr *e, struct nlattr *attr)
132 {
133  struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
134  struct nlattr *tb[NFTA_LOOKUP_MAX+1] = {};
135  int ret = 0;
136 
137  if (mnl_attr_parse_nested(attr, nftnl_expr_lookup_cb, tb) < 0)
138  return -1;
139 
140  if (tb[NFTA_LOOKUP_SREG]) {
141  lookup->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_SREG]));
142  e->flags |= (1 << NFTNL_EXPR_LOOKUP_SREG);
143  }
144  if (tb[NFTA_LOOKUP_DREG]) {
145  lookup->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_DREG]));
146  e->flags |= (1 << NFTNL_EXPR_LOOKUP_DREG);
147  }
148  if (tb[NFTA_LOOKUP_SET]) {
149  lookup->set_name =
150  strdup(mnl_attr_get_str(tb[NFTA_LOOKUP_SET]));
151  if (!lookup->set_name)
152  return -1;
153  e->flags |= (1 << NFTNL_EXPR_LOOKUP_SET);
154  }
155  if (tb[NFTA_LOOKUP_SET_ID]) {
156  lookup->set_id =
157  ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_SET_ID]));
158  e->flags |= (1 << NFTNL_EXPR_LOOKUP_SET_ID);
159  }
160  if (tb[NFTA_LOOKUP_FLAGS]) {
161  lookup->flags = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_FLAGS]));
162  e->flags |= (1 << NFTNL_EXPR_LOOKUP_FLAGS);
163  }
164 
165  return ret;
166 }
167 
168 static int
169 nftnl_expr_lookup_snprintf(char *buf, size_t remain,
170  uint32_t flags, const struct nftnl_expr *e)
171 {
172  struct nftnl_expr_lookup *l = nftnl_expr_data(e);
173  int offset = 0, ret;
174 
175  ret = snprintf(buf, remain, "reg %u set %s ", l->sreg, l->set_name);
176  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
177 
178  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_DREG)) {
179  ret = snprintf(buf + offset, remain, "dreg %u ", l->dreg);
180  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
181  }
182 
183  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_FLAGS)) {
184  ret = snprintf(buf + offset, remain, "0x%x ", l->flags);
185  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
186  }
187 
188  return offset;
189 }
190 
191 static void nftnl_expr_lookup_free(const struct nftnl_expr *e)
192 {
193  struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
194 
195  xfree(lookup->set_name);
196 }
197 
198 static struct attr_policy lookup_attr_policy[__NFTNL_EXPR_LOOKUP_MAX] = {
199  [NFTNL_EXPR_LOOKUP_SREG] = { .maxlen = sizeof(uint32_t) },
200  [NFTNL_EXPR_LOOKUP_DREG] = { .maxlen = sizeof(uint32_t) },
201  [NFTNL_EXPR_LOOKUP_SET] = { .maxlen = NFT_SET_MAXNAMELEN },
202  [NFTNL_EXPR_LOOKUP_SET_ID] = { .maxlen = sizeof(uint32_t) },
203  [NFTNL_EXPR_LOOKUP_FLAGS] = { .maxlen = sizeof(uint32_t) },
204 };
205 
206 struct expr_ops expr_ops_lookup = {
207  .name = "lookup",
208  .alloc_len = sizeof(struct nftnl_expr_lookup),
209  .nftnl_max_attr = __NFTNL_EXPR_LOOKUP_MAX - 1,
210  .attr_policy = lookup_attr_policy,
211  .free = nftnl_expr_lookup_free,
212  .set = nftnl_expr_lookup_set,
213  .get = nftnl_expr_lookup_get,
214  .parse = nftnl_expr_lookup_parse,
215  .build = nftnl_expr_lookup_build,
216  .output = nftnl_expr_lookup_snprintf,
217 };