libnftnl  1.1.5
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, sizeof(tproxy->family));
38  break;
39  case NFTNL_EXPR_TPROXY_REG_ADDR:
40  memcpy(&tproxy->sreg_addr, data, sizeof(tproxy->sreg_addr));
41  break;
42  case NFTNL_EXPR_TPROXY_REG_PORT:
43  memcpy(&tproxy->sreg_port, data, sizeof(tproxy->sreg_port));
44  break;
45  default:
46  return -1;
47  }
48 
49  return 0;
50 }
51 
52 static const void *
53 nftnl_expr_tproxy_get(const struct nftnl_expr *e, uint16_t type,
54  uint32_t *data_len)
55 {
56  struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
57 
58  switch(type) {
59  case NFTNL_EXPR_TPROXY_FAMILY:
60  *data_len = sizeof(tproxy->family);
61  return &tproxy->family;
62  case NFTNL_EXPR_TPROXY_REG_ADDR:
63  *data_len = sizeof(tproxy->sreg_addr);
64  return &tproxy->sreg_addr;
65  case NFTNL_EXPR_TPROXY_REG_PORT:
66  *data_len = sizeof(tproxy->sreg_port);
67  return &tproxy->sreg_port;
68  }
69  return NULL;
70 }
71 
72 static int nftnl_expr_tproxy_cb(const struct nlattr *attr, void *data)
73 {
74  const struct nlattr **tb = data;
75  int type = mnl_attr_get_type(attr);
76 
77  if (mnl_attr_type_valid(attr, NFTA_TPROXY_MAX) < 0)
78  return MNL_CB_OK;
79 
80  switch(type) {
81  case NFTA_TPROXY_FAMILY:
82  case NFTA_TPROXY_REG_ADDR:
83  case NFTA_TPROXY_REG_PORT:
84  if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
85  abi_breakage();
86  break;
87  }
88 
89  tb[type] = attr;
90  return MNL_CB_OK;
91 }
92 
93 static int
94 nftnl_expr_tproxy_parse(struct nftnl_expr *e, struct nlattr *attr)
95 {
96  struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
97  struct nlattr *tb[NFTA_TPROXY_MAX + 1] = {};
98 
99  if (mnl_attr_parse_nested(attr, nftnl_expr_tproxy_cb, tb) < 0)
100  return -1;
101 
102  if (tb[NFTA_TPROXY_FAMILY]) {
103  tproxy->family = ntohl(mnl_attr_get_u32(tb[NFTA_TPROXY_FAMILY]));
104  e->flags |= (1 << NFTNL_EXPR_TPROXY_FAMILY);
105  }
106  if (tb[NFTA_TPROXY_REG_ADDR]) {
107  tproxy->sreg_addr =
108  ntohl(mnl_attr_get_u32(tb[NFTA_TPROXY_REG_ADDR]));
109  e->flags |= (1 << NFTNL_EXPR_TPROXY_REG_ADDR);
110  }
111  if (tb[NFTA_TPROXY_REG_PORT]) {
112  tproxy->sreg_port =
113  ntohl(mnl_attr_get_u32(tb[NFTA_TPROXY_REG_PORT]));
114  e->flags |= (1 << NFTNL_EXPR_TPROXY_REG_PORT);
115  }
116 
117  return 0;
118 }
119 
120 static void
121 nftnl_expr_tproxy_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
122 {
123  struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
124 
125  if (e->flags & (1 << NFTNL_EXPR_TPROXY_FAMILY))
126  mnl_attr_put_u32(nlh, NFTA_TPROXY_FAMILY, htonl(tproxy->family));
127 
128  if (e->flags & (1 << NFTNL_EXPR_TPROXY_REG_ADDR))
129  mnl_attr_put_u32(nlh, NFTA_TPROXY_REG_ADDR,
130  htonl(tproxy->sreg_addr));
131 
132  if (e->flags & (1 << NFTNL_EXPR_TPROXY_REG_PORT))
133  mnl_attr_put_u32(nlh, NFTA_TPROXY_REG_PORT,
134  htonl(tproxy->sreg_port));
135 }
136 
137 static int
138 nftnl_expr_tproxy_snprintf_default(char *buf, size_t size,
139  const struct nftnl_expr *e)
140 {
141  struct nftnl_expr_tproxy *tproxy = nftnl_expr_data(e);
142  int remain = size, offset = 0, ret = 0;
143 
144  if (tproxy->family != NFTA_TPROXY_UNSPEC) {
145  ret = snprintf(buf + offset, remain, "%s ",
146  nftnl_family2str(tproxy->family));
147  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
148  }
149 
150  if (e->flags & (1 << NFTNL_EXPR_TPROXY_REG_ADDR)) {
151  ret = snprintf(buf + offset, remain,
152  "addr reg %u ", tproxy->sreg_addr);
153  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
154  }
155 
156  if (e->flags & (1 << NFTNL_EXPR_TPROXY_REG_PORT)) {
157  ret = snprintf(buf + offset, remain,
158  "port reg %u ", tproxy->sreg_port);
159  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
160  }
161 
162  return offset;
163 }
164 
165 static int
166 nftnl_expr_tproxy_snprintf(char *buf, size_t size, uint32_t type,
167  uint32_t flags, const struct nftnl_expr *e)
168 {
169  switch (type) {
170  case NFTNL_OUTPUT_DEFAULT:
171  return nftnl_expr_tproxy_snprintf_default(buf, size, e);
172  default:
173  break;
174  }
175  return -1;
176 }
177 
178 struct expr_ops expr_ops_tproxy = {
179  .name = "tproxy",
180  .alloc_len = sizeof(struct nftnl_expr_tproxy),
181  .max_attr = NFTA_TPROXY_MAX,
182  .set = nftnl_expr_tproxy_set,
183  .get = nftnl_expr_tproxy_get,
184  .parse = nftnl_expr_tproxy_parse,
185  .build = nftnl_expr_tproxy_build,
186  .snprintf = nftnl_expr_tproxy_snprintf,
187 };