libnftnl  1.2.2
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, sizeof(lookup->sreg));
41  break;
42  case NFTNL_EXPR_LOOKUP_DREG:
43  memcpy(&lookup->dreg, data, sizeof(lookup->dreg));
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, sizeof(lookup->set_id));
52  break;
53  case NFTNL_EXPR_LOOKUP_FLAGS:
54  memcpy(&lookup->flags, data, sizeof(lookup->flags));
55  break;
56  default:
57  return -1;
58  }
59  return 0;
60 }
61 
62 static const void *
63 nftnl_expr_lookup_get(const struct nftnl_expr *e, uint16_t type,
64  uint32_t *data_len)
65 {
66  struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
67 
68  switch(type) {
69  case NFTNL_EXPR_LOOKUP_SREG:
70  *data_len = sizeof(lookup->sreg);
71  return &lookup->sreg;
72  case NFTNL_EXPR_LOOKUP_DREG:
73  *data_len = sizeof(lookup->dreg);
74  return &lookup->dreg;
75  case NFTNL_EXPR_LOOKUP_SET:
76  *data_len = strlen(lookup->set_name) + 1;
77  return lookup->set_name;
78  case NFTNL_EXPR_LOOKUP_SET_ID:
79  *data_len = sizeof(lookup->set_id);
80  return &lookup->set_id;
81  case NFTNL_EXPR_LOOKUP_FLAGS:
82  *data_len = sizeof(lookup->flags);
83  return &lookup->flags;
84  }
85  return NULL;
86 }
87 
88 static int nftnl_expr_lookup_cb(const struct nlattr *attr, void *data)
89 {
90  const struct nlattr **tb = data;
91  int type = mnl_attr_get_type(attr);
92 
93  if (mnl_attr_type_valid(attr, NFTA_LOOKUP_MAX) < 0)
94  return MNL_CB_OK;
95 
96  switch(type) {
97  case NFTA_LOOKUP_SREG:
98  case NFTA_LOOKUP_DREG:
99  case NFTA_LOOKUP_SET_ID:
100  case NFTA_LOOKUP_FLAGS:
101  if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
102  abi_breakage();
103  break;
104  case NFTA_LOOKUP_SET:
105  if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
106  abi_breakage();
107  break;
108  }
109 
110  tb[type] = attr;
111  return MNL_CB_OK;
112 }
113 
114 static void
115 nftnl_expr_lookup_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
116 {
117  struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
118 
119  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_SREG))
120  mnl_attr_put_u32(nlh, NFTA_LOOKUP_SREG, htonl(lookup->sreg));
121  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_DREG))
122  mnl_attr_put_u32(nlh, NFTA_LOOKUP_DREG, htonl(lookup->dreg));
123  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_SET))
124  mnl_attr_put_strz(nlh, NFTA_LOOKUP_SET, lookup->set_name);
125  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_SET_ID))
126  mnl_attr_put_u32(nlh, NFTA_LOOKUP_SET_ID,
127  htonl(lookup->set_id));
128  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_FLAGS))
129  mnl_attr_put_u32(nlh, NFTA_LOOKUP_FLAGS, htonl(lookup->flags));
130 }
131 
132 static int
133 nftnl_expr_lookup_parse(struct nftnl_expr *e, struct nlattr *attr)
134 {
135  struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
136  struct nlattr *tb[NFTA_LOOKUP_MAX+1] = {};
137  int ret = 0;
138 
139  if (mnl_attr_parse_nested(attr, nftnl_expr_lookup_cb, tb) < 0)
140  return -1;
141 
142  if (tb[NFTA_LOOKUP_SREG]) {
143  lookup->sreg = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_SREG]));
144  e->flags |= (1 << NFTNL_EXPR_LOOKUP_SREG);
145  }
146  if (tb[NFTA_LOOKUP_DREG]) {
147  lookup->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_DREG]));
148  e->flags |= (1 << NFTNL_EXPR_LOOKUP_DREG);
149  }
150  if (tb[NFTA_LOOKUP_SET]) {
151  lookup->set_name =
152  strdup(mnl_attr_get_str(tb[NFTA_LOOKUP_SET]));
153  if (!lookup->set_name)
154  return -1;
155  e->flags |= (1 << NFTNL_EXPR_LOOKUP_SET);
156  }
157  if (tb[NFTA_LOOKUP_SET_ID]) {
158  lookup->set_id =
159  ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_SET_ID]));
160  e->flags |= (1 << NFTNL_EXPR_LOOKUP_SET_ID);
161  }
162  if (tb[NFTA_LOOKUP_FLAGS]) {
163  lookup->flags = ntohl(mnl_attr_get_u32(tb[NFTA_LOOKUP_FLAGS]));
164  e->flags |= (1 << NFTNL_EXPR_LOOKUP_FLAGS);
165  }
166 
167  return ret;
168 }
169 
170 static int
171 nftnl_expr_lookup_snprintf(char *buf, size_t remain,
172  uint32_t flags, const struct nftnl_expr *e)
173 {
174  struct nftnl_expr_lookup *l = nftnl_expr_data(e);
175  int offset = 0, ret;
176 
177  ret = snprintf(buf, remain, "reg %u set %s ", l->sreg, l->set_name);
178  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
179 
180  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_DREG)) {
181  ret = snprintf(buf + offset, remain, "dreg %u ", l->dreg);
182  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
183  }
184 
185  if (e->flags & (1 << NFTNL_EXPR_LOOKUP_FLAGS)) {
186  ret = snprintf(buf + offset, remain, "0x%x ", l->flags);
187  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
188  }
189 
190  return offset;
191 }
192 
193 static void nftnl_expr_lookup_free(const struct nftnl_expr *e)
194 {
195  struct nftnl_expr_lookup *lookup = nftnl_expr_data(e);
196 
197  xfree(lookup->set_name);
198 }
199 
200 struct expr_ops expr_ops_lookup = {
201  .name = "lookup",
202  .alloc_len = sizeof(struct nftnl_expr_lookup),
203  .max_attr = NFTA_LOOKUP_MAX,
204  .free = nftnl_expr_lookup_free,
205  .set = nftnl_expr_lookup_set,
206  .get = nftnl_expr_lookup_get,
207  .parse = nftnl_expr_lookup_parse,
208  .build = nftnl_expr_lookup_build,
209  .snprintf = nftnl_expr_lookup_snprintf,
210 };