libnftnl  1.2.8
rt.c
1 /*
2  * Copyright (c) 2016 Anders K. Pedersen <akp@cohaesio.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 <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 
22 struct nftnl_expr_rt {
23  enum nft_rt_keys key;
24  enum nft_registers dreg;
25 };
26 
27 static int
28 nftnl_expr_rt_set(struct nftnl_expr *e, uint16_t type,
29  const void *data, uint32_t data_len)
30 {
31  struct nftnl_expr_rt *rt = nftnl_expr_data(e);
32 
33  switch (type) {
34  case NFTNL_EXPR_RT_KEY:
35  memcpy(&rt->key, data, data_len);
36  break;
37  case NFTNL_EXPR_RT_DREG:
38  memcpy(&rt->dreg, data, data_len);
39  break;
40  }
41  return 0;
42 }
43 
44 static const void *
45 nftnl_expr_rt_get(const struct nftnl_expr *e, uint16_t type,
46  uint32_t *data_len)
47 {
48  struct nftnl_expr_rt *rt = nftnl_expr_data(e);
49 
50  switch (type) {
51  case NFTNL_EXPR_RT_KEY:
52  *data_len = sizeof(rt->key);
53  return &rt->key;
54  case NFTNL_EXPR_RT_DREG:
55  *data_len = sizeof(rt->dreg);
56  return &rt->dreg;
57  }
58  return NULL;
59 }
60 
61 static int nftnl_expr_rt_cb(const struct nlattr *attr, void *data)
62 {
63  const struct nlattr **tb = data;
64  int type = mnl_attr_get_type(attr);
65 
66  if (mnl_attr_type_valid(attr, NFTA_RT_MAX) < 0)
67  return MNL_CB_OK;
68 
69  switch (type) {
70  case NFTA_RT_KEY:
71  case NFTA_RT_DREG:
72  if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
73  abi_breakage();
74  break;
75  }
76 
77  tb[type] = attr;
78  return MNL_CB_OK;
79 }
80 
81 static void
82 nftnl_expr_rt_build(struct nlmsghdr *nlh, const struct nftnl_expr *e)
83 {
84  struct nftnl_expr_rt *rt = nftnl_expr_data(e);
85 
86  if (e->flags & (1 << NFTNL_EXPR_RT_KEY))
87  mnl_attr_put_u32(nlh, NFTA_RT_KEY, htonl(rt->key));
88  if (e->flags & (1 << NFTNL_EXPR_RT_DREG))
89  mnl_attr_put_u32(nlh, NFTA_RT_DREG, htonl(rt->dreg));
90 }
91 
92 static int
93 nftnl_expr_rt_parse(struct nftnl_expr *e, struct nlattr *attr)
94 {
95  struct nftnl_expr_rt *rt = nftnl_expr_data(e);
96  struct nlattr *tb[NFTA_RT_MAX+1] = {};
97 
98  if (mnl_attr_parse_nested(attr, nftnl_expr_rt_cb, tb) < 0)
99  return -1;
100 
101  if (tb[NFTA_RT_KEY]) {
102  rt->key = ntohl(mnl_attr_get_u32(tb[NFTA_RT_KEY]));
103  e->flags |= (1 << NFTNL_EXPR_RT_KEY);
104  }
105  if (tb[NFTA_RT_DREG]) {
106  rt->dreg = ntohl(mnl_attr_get_u32(tb[NFTA_RT_DREG]));
107  e->flags |= (1 << NFTNL_EXPR_RT_DREG);
108  }
109 
110  return 0;
111 }
112 
113 static const char *rt_key2str_array[NFT_RT_MAX + 1] = {
114  [NFT_RT_CLASSID] = "classid",
115  [NFT_RT_NEXTHOP4] = "nexthop4",
116  [NFT_RT_NEXTHOP6] = "nexthop6",
117  [NFT_RT_TCPMSS] = "tcpmss",
118  [NFT_RT_XFRM] = "ipsec",
119 };
120 
121 static const char *rt_key2str(uint8_t key)
122 {
123  if (key <= NFT_RT_MAX)
124  return rt_key2str_array[key];
125 
126  return "unknown";
127 }
128 
129 static inline int str2rt_key(const char *str)
130 {
131  int i;
132 
133  for (i = 0; i < NFT_RT_MAX; i++) {
134  if (strcmp(str, rt_key2str_array[i]) == 0)
135  return i;
136  }
137 
138  errno = EINVAL;
139  return -1;
140 }
141 
142 static int
143 nftnl_expr_rt_snprintf(char *buf, size_t len,
144  uint32_t flags, const struct nftnl_expr *e)
145 {
146  struct nftnl_expr_rt *rt = nftnl_expr_data(e);
147 
148  if (e->flags & (1 << NFTNL_EXPR_RT_DREG)) {
149  return snprintf(buf, len, "load %s => reg %u ",
150  rt_key2str(rt->key), rt->dreg);
151  }
152  return 0;
153 }
154 
155 static struct attr_policy rt_attr_policy[__NFTNL_EXPR_RT_MAX] = {
156  [NFTNL_EXPR_RT_KEY] = { .maxlen = sizeof(uint32_t) },
157  [NFTNL_EXPR_RT_DREG] = { .maxlen = sizeof(uint32_t) },
158 };
159 
160 struct expr_ops expr_ops_rt = {
161  .name = "rt",
162  .alloc_len = sizeof(struct nftnl_expr_rt),
163  .nftnl_max_attr = __NFTNL_EXPR_RT_MAX - 1,
164  .attr_policy = rt_attr_policy,
165  .set = nftnl_expr_rt_set,
166  .get = nftnl_expr_rt_get,
167  .parse = nftnl_expr_rt_parse,
168  .build = nftnl_expr_rt_build,
169  .output = nftnl_expr_rt_snprintf,
170 };