libnftnl  1.1.5
fwd.c
1 /*
2  * (C) 2015 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 "internal.h"
16 #include <libmnl/libmnl.h>
17 #include <linux/netfilter/nf_tables.h>
18 #include <libnftnl/expr.h>
19 #include <libnftnl/rule.h>
20 #include "expr_ops.h"
21 #include "data_reg.h"
22 #include <buffer.h>
23 
25  enum nft_registers sreg_dev;
26  enum nft_registers sreg_addr;
27  uint32_t nfproto;
28 };
29 
30 static int nftnl_expr_fwd_set(struct nftnl_expr *e, uint16_t type,
31  const void *data, uint32_t data_len)
32 {
33  struct nftnl_expr_fwd *fwd = nftnl_expr_data(e);
34 
35  switch (type) {
36  case NFTNL_EXPR_FWD_SREG_DEV:
37  memcpy(&fwd->sreg_dev, data, sizeof(fwd->sreg_dev));
38  break;
39  case NFTNL_EXPR_FWD_SREG_ADDR:
40  memcpy(&fwd->sreg_addr, data, sizeof(fwd->sreg_addr));
41  break;
42  case NFTNL_EXPR_FWD_NFPROTO:
43  memcpy(&fwd->nfproto, data, sizeof(fwd->nfproto));
44  break;
45  default:
46  return -1;
47  }
48  return 0;
49 }
50 
51 static const void *nftnl_expr_fwd_get(const struct nftnl_expr *e,
52  uint16_t type, uint32_t *data_len)
53 {
54  struct nftnl_expr_fwd *fwd = nftnl_expr_data(e);
55 
56  switch (type) {
57  case NFTNL_EXPR_FWD_SREG_DEV:
58  *data_len = sizeof(fwd->sreg_dev);
59  return &fwd->sreg_dev;
60  case NFTNL_EXPR_FWD_SREG_ADDR:
61  *data_len = sizeof(fwd->sreg_addr);
62  return &fwd->sreg_addr;
63  case NFTNL_EXPR_FWD_NFPROTO:
64  *data_len = sizeof(fwd->nfproto);
65  return &fwd->nfproto;
66  }
67  return NULL;
68 }
69 
70 static int nftnl_expr_fwd_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_FWD_MAX) < 0)
76  return MNL_CB_OK;
77 
78  switch (type) {
79  case NFTA_FWD_SREG_DEV:
80  case NFTA_FWD_SREG_ADDR:
81  case NFTA_FWD_NFPROTO:
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 void nftnl_expr_fwd_build(struct nlmsghdr *nlh,
92  const struct nftnl_expr *e)
93 {
94  struct nftnl_expr_fwd *fwd = nftnl_expr_data(e);
95 
96  if (e->flags & (1 << NFTNL_EXPR_FWD_SREG_DEV))
97  mnl_attr_put_u32(nlh, NFTA_FWD_SREG_DEV, htonl(fwd->sreg_dev));
98  if (e->flags & (1 << NFTNL_EXPR_FWD_SREG_ADDR))
99  mnl_attr_put_u32(nlh, NFTA_FWD_SREG_ADDR, htonl(fwd->sreg_addr));
100  if (e->flags & (1 << NFTNL_EXPR_FWD_NFPROTO))
101  mnl_attr_put_u32(nlh, NFTA_FWD_NFPROTO, htonl(fwd->nfproto));
102 }
103 
104 static int nftnl_expr_fwd_parse(struct nftnl_expr *e, struct nlattr *attr)
105 {
106  struct nftnl_expr_fwd *fwd = nftnl_expr_data(e);
107  struct nlattr *tb[NFTA_FWD_MAX + 1] = {};
108  int ret = 0;
109 
110  if (mnl_attr_parse_nested(attr, nftnl_expr_fwd_cb, tb) < 0)
111  return -1;
112 
113  if (tb[NFTA_FWD_SREG_DEV]) {
114  fwd->sreg_dev = ntohl(mnl_attr_get_u32(tb[NFTA_FWD_SREG_DEV]));
115  e->flags |= (1 << NFTNL_EXPR_FWD_SREG_DEV);
116  }
117  if (tb[NFTA_FWD_SREG_ADDR]) {
118  fwd->sreg_addr = ntohl(mnl_attr_get_u32(tb[NFTA_FWD_SREG_ADDR]));
119  e->flags |= (1 << NFTNL_EXPR_FWD_SREG_ADDR);
120  }
121  if (tb[NFTA_FWD_NFPROTO]) {
122  fwd->nfproto = ntohl(mnl_attr_get_u32(tb[NFTA_FWD_NFPROTO]));
123  e->flags |= (1 << NFTNL_EXPR_FWD_NFPROTO);
124  }
125 
126  return ret;
127 }
128 
129 static int nftnl_expr_fwd_snprintf_default(char *buf, size_t len,
130  const struct nftnl_expr *e,
131  uint32_t flags)
132 {
133  int remain = len, offset = 0, ret;
134  struct nftnl_expr_fwd *fwd = nftnl_expr_data(e);
135 
136  if (e->flags & (1 << NFTNL_EXPR_FWD_SREG_DEV)) {
137  ret = snprintf(buf + offset, remain, "sreg_dev %u ",
138  fwd->sreg_dev);
139  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
140  }
141  if (e->flags & (1 << NFTNL_EXPR_FWD_SREG_ADDR)) {
142  ret = snprintf(buf + offset, remain, "sreg_addr %u ",
143  fwd->sreg_addr);
144  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
145  }
146  if (e->flags & (1 << NFTNL_EXPR_FWD_NFPROTO)) {
147  ret = snprintf(buf + offset, remain, "nfproto %u ",
148  fwd->nfproto);
149  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
150  }
151 
152  return offset;
153 }
154 
155 static int nftnl_expr_fwd_snprintf(char *buf, size_t len, uint32_t type,
156  uint32_t flags, const struct nftnl_expr *e)
157 {
158  switch (type) {
159  case NFTNL_OUTPUT_DEFAULT:
160  return nftnl_expr_fwd_snprintf_default(buf, len, e, flags);
161  case NFTNL_OUTPUT_XML:
162  case NFTNL_OUTPUT_JSON:
163  default:
164  break;
165  }
166  return -1;
167 }
168 
169 struct expr_ops expr_ops_fwd = {
170  .name = "fwd",
171  .alloc_len = sizeof(struct nftnl_expr_fwd),
172  .max_attr = NFTA_FWD_MAX,
173  .set = nftnl_expr_fwd_set,
174  .get = nftnl_expr_fwd_get,
175  .parse = nftnl_expr_fwd_parse,
176  .build = nftnl_expr_fwd_build,
177  .snprintf = nftnl_expr_fwd_snprintf,
178 };