libnftnl  1.2.8
expr/limit.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 <stdio.h>
13 #include <stdint.h>
14 #include <inttypes.h>
15 #include <string.h>
16 #include <arpa/inet.h>
17 #include <errno.h>
18 #include <linux/netfilter/nf_tables.h>
19 
20 #include "internal.h"
21 #include <libmnl/libmnl.h>
22 #include <libnftnl/expr.h>
23 #include <libnftnl/rule.h>
24 
26  uint64_t rate;
27  uint64_t unit;
28  uint32_t burst;
29  enum nft_limit_type type;
30  uint32_t flags;
31 };
32 
33 static int
34 nftnl_expr_limit_set(struct nftnl_expr *e, uint16_t type,
35  const void *data, uint32_t data_len)
36 {
37  struct nftnl_expr_limit *limit = nftnl_expr_data(e);
38 
39  switch(type) {
40  case NFTNL_EXPR_LIMIT_RATE:
41  memcpy(&limit->rate, data, data_len);
42  break;
43  case NFTNL_EXPR_LIMIT_UNIT:
44  memcpy(&limit->unit, data, data_len);
45  break;
46  case NFTNL_EXPR_LIMIT_BURST:
47  memcpy(&limit->burst, data, data_len);
48  break;
49  case NFTNL_EXPR_LIMIT_TYPE:
50  memcpy(&limit->type, data, data_len);
51  break;
52  case NFTNL_EXPR_LIMIT_FLAGS:
53  memcpy(&limit->flags, data, data_len);
54  break;
55  }
56  return 0;
57 }
58 
59 static const void *
60 nftnl_expr_limit_get(const struct nftnl_expr *e, uint16_t type,
61  uint32_t *data_len)
62 {
63  struct nftnl_expr_limit *limit = nftnl_expr_data(e);
64 
65  switch(type) {
66  case NFTNL_EXPR_LIMIT_RATE:
67  *data_len = sizeof(uint64_t);
68  return &limit->rate;
69  case NFTNL_EXPR_LIMIT_UNIT:
70  *data_len = sizeof(uint64_t);
71  return &limit->unit;
72  case NFTNL_EXPR_LIMIT_BURST:
73  *data_len = sizeof(uint32_t);
74  return &limit->burst;
75  case NFTNL_EXPR_LIMIT_TYPE:
76  *data_len = sizeof(uint32_t);
77  return &limit->type;
78  case NFTNL_EXPR_LIMIT_FLAGS:
79  *data_len = sizeof(uint32_t);
80  return &limit->flags;
81  }
82  return NULL;
83 }
84 
85 static int nftnl_expr_limit_cb(const struct nlattr *attr, void *data)
86 {
87  const struct nlattr **tb = data;
88  int type = mnl_attr_get_type(attr);
89 
90  if (mnl_attr_type_valid(attr, NFTA_LIMIT_MAX) < 0)
91  return MNL_CB_OK;
92 
93  switch(type) {
94  case NFTA_LIMIT_RATE:
95  case NFTA_LIMIT_UNIT:
96  if (mnl_attr_validate(attr, MNL_TYPE_U64) < 0)
97  abi_breakage();
98  break;
99  case NFTA_LIMIT_BURST:
100  case NFTA_LIMIT_TYPE:
101  case NFTA_LIMIT_FLAGS:
102  if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
103  abi_breakage();
104  break;
105  }
106 
107  tb[type] = attr;
108  return MNL_CB_OK;
109 }
110 
111 static void
112 nftnl_expr_limit_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
113 {
114  struct nftnl_expr_limit *limit = nftnl_expr_data(e);
115 
116  if (e->flags & (1 << NFTNL_EXPR_LIMIT_RATE))
117  mnl_attr_put_u64(nlh, NFTA_LIMIT_RATE, htobe64(limit->rate));
118  if (e->flags & (1 << NFTNL_EXPR_LIMIT_UNIT))
119  mnl_attr_put_u64(nlh, NFTA_LIMIT_UNIT, htobe64(limit->unit));
120  if (e->flags & (1 << NFTNL_EXPR_LIMIT_BURST))
121  mnl_attr_put_u32(nlh, NFTA_LIMIT_BURST, htonl(limit->burst));
122  if (e->flags & (1 << NFTNL_EXPR_LIMIT_TYPE))
123  mnl_attr_put_u32(nlh, NFTA_LIMIT_TYPE, htonl(limit->type));
124  if (e->flags & (1 << NFTNL_EXPR_LIMIT_FLAGS))
125  mnl_attr_put_u32(nlh, NFTA_LIMIT_FLAGS, htonl(limit->flags));
126 }
127 
128 static int
129 nftnl_expr_limit_parse(struct nftnl_expr *e, struct nlattr *attr)
130 {
131  struct nftnl_expr_limit *limit = nftnl_expr_data(e);
132  struct nlattr *tb[NFTA_LIMIT_MAX+1] = {};
133 
134  if (mnl_attr_parse_nested(attr, nftnl_expr_limit_cb, tb) < 0)
135  return -1;
136 
137  if (tb[NFTA_LIMIT_RATE]) {
138  limit->rate = be64toh(mnl_attr_get_u64(tb[NFTA_LIMIT_RATE]));
139  e->flags |= (1 << NFTNL_EXPR_LIMIT_RATE);
140  }
141  if (tb[NFTA_LIMIT_UNIT]) {
142  limit->unit = be64toh(mnl_attr_get_u64(tb[NFTA_LIMIT_UNIT]));
143  e->flags |= (1 << NFTNL_EXPR_LIMIT_UNIT);
144  }
145  if (tb[NFTA_LIMIT_BURST]) {
146  limit->burst = ntohl(mnl_attr_get_u32(tb[NFTA_LIMIT_BURST]));
147  e->flags |= (1 << NFTNL_EXPR_LIMIT_BURST);
148  }
149  if (tb[NFTA_LIMIT_TYPE]) {
150  limit->type = ntohl(mnl_attr_get_u32(tb[NFTA_LIMIT_TYPE]));
151  e->flags |= (1 << NFTNL_EXPR_LIMIT_TYPE);
152  }
153  if (tb[NFTA_LIMIT_FLAGS]) {
154  limit->flags = ntohl(mnl_attr_get_u32(tb[NFTA_LIMIT_FLAGS]));
155  e->flags |= (1 << NFTNL_EXPR_LIMIT_FLAGS);
156  }
157 
158  return 0;
159 }
160 
161 static const char *get_time(uint64_t seconds, uint64_t *val)
162 {
163  static const struct {
164  unsigned int size;
165  const char *name;
166  } units[] = {
167  { 0, "second" },
168  { 60, "minute" },
169  { 60, "hour" },
170  { 24, "day" },
171  { 7, "week" }
172  };
173  int i;
174 
175  for (i = 1; i < array_size(units); i++) {
176  if (seconds % units[i].size)
177  break;
178  seconds /= units[i].size;
179  }
180  if (val)
181  *val = seconds;
182  return units[i - 1].name;
183 }
184 
185 static const char *limit_to_type(enum nft_limit_type type)
186 {
187  switch (type) {
188  default:
189  case NFT_LIMIT_PKTS:
190  return "packets";
191  case NFT_LIMIT_PKT_BYTES:
192  return "bytes";
193  }
194 }
195 
196 static int
197 nftnl_expr_limit_snprintf(char *buf, size_t len,
198  uint32_t flags, const struct nftnl_expr *e)
199 {
200  struct nftnl_expr_limit *limit = nftnl_expr_data(e);
201  unsigned int offset = 0;
202  const char *time_unit;
203  uint64_t time_val;
204  int ret;
205 
206  ret = snprintf(buf, len, "rate %"PRIu64"/", limit->rate);
207  SNPRINTF_BUFFER_SIZE(ret, len, offset);
208 
209  time_unit = get_time(limit->unit, &time_val);
210  if (time_val > 1) {
211  ret = snprintf(buf + offset, len, "%"PRIu64" ", time_val);
212  SNPRINTF_BUFFER_SIZE(ret, len, offset);
213  }
214 
215  ret = snprintf(buf + offset, len, "%s burst %u type %s flags 0x%x ",
216  time_unit, limit->burst, limit_to_type(limit->type),
217  limit->flags);
218  SNPRINTF_BUFFER_SIZE(ret, len, offset);
219 
220  return offset;
221 }
222 
223 static struct attr_policy limit_attr_policy[__NFTNL_EXPR_LIMIT_MAX] = {
224  [NFTNL_EXPR_LIMIT_RATE] = { .maxlen = sizeof(uint64_t) },
225  [NFTNL_EXPR_LIMIT_UNIT] = { .maxlen = sizeof(uint64_t) },
226  [NFTNL_EXPR_LIMIT_BURST] = { .maxlen = sizeof(uint32_t) },
227  [NFTNL_EXPR_LIMIT_TYPE] = { .maxlen = sizeof(uint32_t) },
228  [NFTNL_EXPR_LIMIT_FLAGS] = { .maxlen = sizeof(uint32_t) },
229 };
230 
231 struct expr_ops expr_ops_limit = {
232  .name = "limit",
233  .alloc_len = sizeof(struct nftnl_expr_limit),
234  .nftnl_max_attr = __NFTNL_EXPR_LIMIT_MAX - 1,
235  .attr_policy = limit_attr_policy,
236  .set = nftnl_expr_limit_set,
237  .get = nftnl_expr_limit_get,
238  .parse = nftnl_expr_limit_parse,
239  .build = nftnl_expr_limit_build,
240  .output = nftnl_expr_limit_snprintf,
241 };