libnftnl  1.2.8
tproxy.c
1 /*
2  * Copyright (c) 2018 Máté Eckl <ecklm94@gmail.com>
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 
10 #include "internal.h"
11 
12 #include <stdio.h>
13 #include <stdint.h>
14 #include <limits.h>
15 #include <string.h>
16 #include <errno.h>
17 #include <arpa/inet.h>
18 #include <libmnl/libmnl.h>
19 #include <linux/netfilter/nf_tables.h>
20 #include <libnftnl/expr.h>
21 #include <libnftnl/rule.h>
22 
24  enum nft_registers sreg_addr;
25  enum nft_registers sreg_port;
26  int family;
27 };
28 
29 static int
30 nftnl_expr_tproxy_set(struct nftnl_expr *e, uint16_t type,
31  const void *data, uint32_t data_len)
32 {
33  struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
34 
35  switch(type) {
36  case NFTNL_EXPR_TPROXY_FAMILY:
37  memcpy(&tproxy->family, data, data_len);
38  break;
39  case NFTNL_EXPR_TPROXY_REG_ADDR:
40  memcpy(&tproxy->sreg_addr, data, data_len);
41  break;
42  case NFTNL_EXPR_TPROXY_REG_PORT:
43  memcpy(&tproxy->sreg_port, data, data_len);
44  break;
45  }
46 
47  return 0;
48 }
49 
50 static const void *
51 nftnl_expr_tproxy_get(const struct nftnl_expr *e, uint16_t type,
52  uint32_t *data_len)
53 {
54  struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
55 
56  switch(type) {
57  case NFTNL_EXPR_TPROXY_FAMILY:
58  *data_len = sizeof(tproxy->family);
59  return &tproxy->family;
60  case NFTNL_EXPR_TPROXY_REG_ADDR:
61  *data_len = sizeof(tproxy->sreg_addr);
62  return &tproxy->sreg_addr;
63  case NFTNL_EXPR_TPROXY_REG_PORT:
64  *data_len = sizeof(tproxy->sreg_port);
65  return &tproxy->sreg_port;
66  }
67  return NULL;
68 }
69 
70 static int nftnl_expr_tproxy_cb(const struct nlattr *attr, void *data)
71 {
72  const struct nlattr **tb = data;
73  int type = mnl_attr_get_type(attr);
74 
75  if (mnl_attr_type_valid(attr, NFTA_TPROXY_MAX) < 0)
76  return MNL_CB_OK;
77 
78  switch(type) {
79  case NFTA_TPROXY_FAMILY:
80  case NFTA_TPROXY_REG_ADDR:
81  case NFTA_TPROXY_REG_PORT:
82  if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
83  abi_breakage();
84  break;
85  }
86 
87  tb[type] = attr;
88  return MNL_CB_OK;
89 }
90 
91 static int
92 nftnl_expr_tproxy_parse(struct nftnl_expr *e, struct nlattr *attr)
93 {
94  struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
95  struct nlattr *tb[NFTA_TPROXY_MAX + 1] = {};
96 
97  if (mnl_attr_parse_nested(attr, nftnl_expr_tproxy_cb, tb) < 0)
98  return -1;
99 
100  if (tb[NFTA_TPROXY_FAMILY]) {
101  tproxy->family = ntohl(mnl_attr_get_u32(tb[NFTA_TPROXY_FAMILY]));
102  e->flags |= (1 << NFTNL_EXPR_TPROXY_FAMILY);
103  }
104  if (tb[NFTA_TPROXY_REG_ADDR]) {
105  tproxy->sreg_addr =
106  ntohl(mnl_attr_get_u32(tb[NFTA_TPROXY_REG_ADDR]));
107  e->flags |= (1 << NFTNL_EXPR_TPROXY_REG_ADDR);
108  }
109  if (tb[NFTA_TPROXY_REG_PORT]) {
110  tproxy->sreg_port =
111  ntohl(mnl_attr_get_u32(tb[NFTA_TPROXY_REG_PORT]));
112  e->flags |= (1 << NFTNL_EXPR_TPROXY_REG_PORT);
113  }
114 
115  return 0;
116 }
117 
118 static void
119 nftnl_expr_tproxy_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
120 {
121  struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
122 
123  if (e->flags & (1 << NFTNL_EXPR_TPROXY_FAMILY))
124  mnl_attr_put_u32(nlh, NFTA_TPROXY_FAMILY, htonl(tproxy->family));
125 
126  if (e->flags & (1 << NFTNL_EXPR_TPROXY_REG_ADDR))
127  mnl_attr_put_u32(nlh, NFTA_TPROXY_REG_ADDR,
128  htonl(tproxy->sreg_addr));
129 
130  if (e->flags & (1 << NFTNL_EXPR_TPROXY_REG_PORT))
131  mnl_attr_put_u32(nlh, NFTA_TPROXY_REG_PORT,
132  htonl(tproxy->sreg_port));
133 }
134 
135 static int
136 nftnl_expr_tproxy_snprintf(char *buf, size_t remain,
137  uint32_t flags, const struct nftnl_expr *e)
138 {
139  struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
140  int offset = 0, ret = 0;
141 
142  if (tproxy->family != NFTA_TPROXY_UNSPEC) {
143  ret = snprintf(buf + offset, remain, "%s ",
144  nftnl_family2str(tproxy->family));
145  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
146  }
147 
148  if (e->flags & (1 << NFTNL_EXPR_TPROXY_REG_ADDR)) {
149  ret = snprintf(buf + offset, remain,
150  "addr reg %u ", tproxy->sreg_addr);
151  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
152  }
153 
154  if (e->flags & (1 << NFTNL_EXPR_TPROXY_REG_PORT)) {
155  ret = snprintf(buf + offset, remain,
156  "port reg %u ", tproxy->sreg_port);
157  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
158  }
159 
160  return offset;
161 }
162 
163 static struct attr_policy tproxy_attr_policy[__NFTNL_EXPR_TPROXY_MAX] = {
164  [NFTNL_EXPR_TPROXY_FAMILY] = { .maxlen = sizeof(uint32_t) },
165  [NFTNL_EXPR_TPROXY_REG_ADDR] = { .maxlen = sizeof(uint32_t) },
166  [NFTNL_EXPR_TPROXY_REG_PORT] = { .maxlen = sizeof(uint32_t) },
167 };
168 
169 struct expr_ops expr_ops_tproxy = {
170  .name = "tproxy",
171  .alloc_len = sizeof(struct nftnl_expr_tproxy),
172  .nftnl_max_attr = __NFTNL_EXPR_TPROXY_MAX - 1,
173  .attr_policy = tproxy_attr_policy,
174  .set = nftnl_expr_tproxy_set,
175  .get = nftnl_expr_tproxy_get,
176  .parse = nftnl_expr_tproxy_parse,
177  .build = nftnl_expr_tproxy_build,
178  .output = nftnl_expr_tproxy_snprintf,
179 };