libnftnl  1.2.8
expr/tunnel.c
1 /*
2  * (C) 2018 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 
10 #include <stdio.h>
11 #include <stdint.h>
12 #include <string.h>
13 #include <arpa/inet.h>
14 #include <errno.h>
15 #include <linux/netfilter/nf_tables.h>
16 
17 #include "internal.h"
18 #include <libmnl/libmnl.h>
19 #include <libnftnl/expr.h>
20 #include <libnftnl/rule.h>
21 
23  enum nft_tunnel_keys key;
24  enum nft_registers dreg;
25 };
26 
27 static int nftnl_expr_tunnel_set(struct nftnl_expr *e, uint16_t type,
28  const void *data, uint32_t data_len)
29 {
30  struct nftnl_expr_tunnel *tunnel = nftnl_expr_data(e);
31 
32  switch(type) {
33  case NFTNL_EXPR_TUNNEL_KEY:
34  memcpy(&tunnel->key, data, data_len);
35  break;
36  case NFTNL_EXPR_TUNNEL_DREG:
37  memcpy(&tunnel->dreg, data, data_len);
38  break;
39  }
40  return 0;
41 }
42 
43 static const void *
44 nftnl_expr_tunnel_get(const struct nftnl_expr *e, uint16_t type,
45  uint32_t *data_len)
46 {
47  struct nftnl_expr_tunnel *tunnel = nftnl_expr_data(e);
48 
49  switch(type) {
50  case NFTNL_EXPR_TUNNEL_KEY:
51  *data_len = sizeof(tunnel->key);
52  return &tunnel->key;
53  case NFTNL_EXPR_TUNNEL_DREG:
54  *data_len = sizeof(tunnel->dreg);
55  return &tunnel->dreg;
56  }
57  return NULL;
58 }
59 
60 static int nftnl_expr_tunnel_cb(const struct nlattr *attr, void *data)
61 {
62  const struct nlattr **tb = data;
63  int type = mnl_attr_get_type(attr);
64 
65  if (mnl_attr_type_valid(attr, NFTA_TUNNEL_MAX) < 0)
66  return MNL_CB_OK;
67 
68  switch(type) {
69  case NFTA_TUNNEL_KEY:
70  case NFTA_TUNNEL_DREG:
71  if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
72  abi_breakage();
73  break;
74  }
75 
76  tb[type] = attr;
77  return MNL_CB_OK;
78 }
79 
80 static void
81 nftnl_expr_tunnel_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
82 {
83  struct nftnl_expr_tunnel *tunnel = nftnl_expr_data(e);
84 
85  if (e->flags & (1 << NFTNL_EXPR_TUNNEL_KEY))
86  mnl_attr_put_u32(nlh, NFTA_TUNNEL_KEY, htonl(tunnel->key));
87  if (e->flags & (1 << NFTNL_EXPR_TUNNEL_DREG))
88  mnl_attr_put_u32(nlh, NFTA_TUNNEL_DREG, htonl(tunnel->dreg));
89 }
90 
91 static int
92 nftnl_expr_tunnel_parse(struct nftnl_expr *e, struct nlattr *attr)
93 {
94  struct nftnl_expr_tunnel *tunnel = nftnl_expr_data(e);
95  struct nlattr *tb[NFTA_TUNNEL_MAX + 1] = {};
96 
97  if (mnl_attr_parse_nested(attr, nftnl_expr_tunnel_cb, tb) < 0)
98  return -1;
99 
100  if (tb[NFTA_TUNNEL_KEY]) {
101  tunnel->key = ntohl(mnl_attr_get_u32(tb[NFTA_TUNNEL_KEY]));
102  e->flags |= (1 << NFTNL_EXPR_TUNNEL_KEY);
103  }
104  if (tb[NFTA_TUNNEL_DREG]) {
105  tunnel->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_TUNNEL_DREG]));
106  e->flags |= (1 << NFTNL_EXPR_TUNNEL_DREG);
107  }
108 
109  return 0;
110 }
111 
112 static const char *tunnel_key2str_array[NFT_TUNNEL_MAX + 1] = {
113  [NFT_TUNNEL_PATH] = "path",
114  [NFT_TUNNEL_ID] = "id",
115 };
116 
117 static const char *tunnel_key2str(uint8_t key)
118 {
119  if (key <= NFT_TUNNEL_MAX)
120  return tunnel_key2str_array[key];
121 
122  return "unknown";
123 }
124 
125 static int
126 nftnl_expr_tunnel_snprintf(char *buf, size_t len,
127  uint32_t flags, const struct nftnl_expr *e)
128 {
129  struct nftnl_expr_tunnel *tunnel = nftnl_expr_data(e);
130 
131  if (e->flags & (1 << NFTNL_EXPR_TUNNEL_DREG)) {
132  return snprintf(buf, len, "load %s => reg %u ",
133  tunnel_key2str(tunnel->key), tunnel->dreg);
134  }
135  return 0;
136 }
137 
138 static struct attr_policy tunnel_attr_policy[__NFTNL_EXPR_TUNNEL_MAX] = {
139  [NFTNL_EXPR_TUNNEL_KEY] = { .maxlen = sizeof(uint32_t) },
140  [NFTNL_EXPR_TUNNEL_DREG] = { .maxlen = sizeof(uint32_t) },
141 };
142 
143 struct expr_ops expr_ops_tunnel = {
144  .name = "tunnel",
145  .alloc_len = sizeof(struct nftnl_expr_tunnel),
146  .nftnl_max_attr = __NFTNL_EXPR_TUNNEL_MAX - 1,
147  .attr_policy = tunnel_attr_policy,
148  .set = nftnl_expr_tunnel_set,
149  .get = nftnl_expr_tunnel_get,
150  .parse = nftnl_expr_tunnel_parse,
151  .build = nftnl_expr_tunnel_build,
152  .output = nftnl_expr_tunnel_snprintf,
153 };