libnftnl  1.2.8
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 
24  enum nft_registers sreg_dev;
25  enum nft_registers sreg_addr;
26  uint32_t nfproto;
27 };
28 
29 static int nftnl_expr_fwd_set(struct nftnl_expr *e, uint16_t type,
30  const void *data, uint32_t data_len)
31 {
32  struct nftnl_expr_fwd *fwd = nftnl_expr_data(e);
33 
34  switch (type) {
35  case NFTNL_EXPR_FWD_SREG_DEV:
36  memcpy(&fwd->sreg_dev, data, data_len);
37  break;
38  case NFTNL_EXPR_FWD_SREG_ADDR:
39  memcpy(&fwd->sreg_addr, data, data_len);
40  break;
41  case NFTNL_EXPR_FWD_NFPROTO:
42  memcpy(&fwd->nfproto, data, data_len);
43  break;
44  }
45  return 0;
46 }
47 
48 static const void *nftnl_expr_fwd_get(const struct nftnl_expr *e,
49  uint16_t type, uint32_t *data_len)
50 {
51  struct nftnl_expr_fwd *fwd = nftnl_expr_data(e);
52 
53  switch (type) {
54  case NFTNL_EXPR_FWD_SREG_DEV:
55  *data_len = sizeof(fwd->sreg_dev);
56  return &fwd->sreg_dev;
57  case NFTNL_EXPR_FWD_SREG_ADDR:
58  *data_len = sizeof(fwd->sreg_addr);
59  return &fwd->sreg_addr;
60  case NFTNL_EXPR_FWD_NFPROTO:
61  *data_len = sizeof(fwd->nfproto);
62  return &fwd->nfproto;
63  }
64  return NULL;
65 }
66 
67 static int nftnl_expr_fwd_cb(const struct nlattr *attr, void *data)
68 {
69  const struct nlattr **tb = data;
70  int type = mnl_attr_get_type(attr);
71 
72  if (mnl_attr_type_valid(attr, NFTA_FWD_MAX) < 0)
73  return MNL_CB_OK;
74 
75  switch (type) {
76  case NFTA_FWD_SREG_DEV:
77  case NFTA_FWD_SREG_ADDR:
78  case NFTA_FWD_NFPROTO:
79  if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0)
80  abi_breakage();
81  break;
82  }
83 
84  tb[type] = attr;
85  return MNL_CB_OK;
86 }
87 
88 static void nftnl_expr_fwd_build(struct nlmsghdr *nlh,
89  const struct nftnl_expr *e)
90 {
91  struct nftnl_expr_fwd *fwd = nftnl_expr_data(e);
92 
93  if (e->flags & (1 << NFTNL_EXPR_FWD_SREG_DEV))
94  mnl_attr_put_u32(nlh, NFTA_FWD_SREG_DEV, htonl(fwd->sreg_dev));
95  if (e->flags & (1 << NFTNL_EXPR_FWD_SREG_ADDR))
96  mnl_attr_put_u32(nlh, NFTA_FWD_SREG_ADDR, htonl(fwd->sreg_addr));
97  if (e->flags & (1 << NFTNL_EXPR_FWD_NFPROTO))
98  mnl_attr_put_u32(nlh, NFTA_FWD_NFPROTO, htonl(fwd->nfproto));
99 }
100 
101 static int nftnl_expr_fwd_parse(struct nftnl_expr *e, struct nlattr *attr)
102 {
103  struct nftnl_expr_fwd *fwd = nftnl_expr_data(e);
104  struct nlattr *tb[NFTA_FWD_MAX + 1] = {};
105  int ret = 0;
106 
107  if (mnl_attr_parse_nested(attr, nftnl_expr_fwd_cb, tb) < 0)
108  return -1;
109 
110  if (tb[NFTA_FWD_SREG_DEV]) {
111  fwd->sreg_dev = ntohl(mnl_attr_get_u32(tb[NFTA_FWD_SREG_DEV]));
112  e->flags |= (1 << NFTNL_EXPR_FWD_SREG_DEV);
113  }
114  if (tb[NFTA_FWD_SREG_ADDR]) {
115  fwd->sreg_addr = ntohl(mnl_attr_get_u32(tb[NFTA_FWD_SREG_ADDR]));
116  e->flags |= (1 << NFTNL_EXPR_FWD_SREG_ADDR);
117  }
118  if (tb[NFTA_FWD_NFPROTO]) {
119  fwd->nfproto = ntohl(mnl_attr_get_u32(tb[NFTA_FWD_NFPROTO]));
120  e->flags |= (1 << NFTNL_EXPR_FWD_NFPROTO);
121  }
122 
123  return ret;
124 }
125 
126 static int nftnl_expr_fwd_snprintf(char *buf, size_t remain,
127  uint32_t flags, const struct nftnl_expr *e)
128 {
129  struct nftnl_expr_fwd *fwd = nftnl_expr_data(e);
130  int offset = 0, ret;
131 
132  if (e->flags & (1 << NFTNL_EXPR_FWD_SREG_DEV)) {
133  ret = snprintf(buf + offset, remain, "sreg_dev %u ",
134  fwd->sreg_dev);
135  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
136  }
137  if (e->flags & (1 << NFTNL_EXPR_FWD_SREG_ADDR)) {
138  ret = snprintf(buf + offset, remain, "sreg_addr %u ",
139  fwd->sreg_addr);
140  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
141  }
142  if (e->flags & (1 << NFTNL_EXPR_FWD_NFPROTO)) {
143  ret = snprintf(buf + offset, remain, "nfproto %u ",
144  fwd->nfproto);
145  SNPRINTF_BUFFER_SIZE(ret, remain, offset);
146  }
147 
148  return offset;
149 }
150 
151 static struct attr_policy fwd_attr_policy[__NFTNL_EXPR_FWD_MAX] = {
152  [NFTNL_EXPR_FWD_SREG_DEV] = { .maxlen = sizeof(uint32_t) },
153  [NFTNL_EXPR_FWD_SREG_ADDR] = { .maxlen = sizeof(uint32_t) },
154  [NFTNL_EXPR_FWD_NFPROTO] = { .maxlen = sizeof(uint32_t) },
155 };
156 
157 struct expr_ops expr_ops_fwd = {
158  .name = "fwd",
159  .alloc_len = sizeof(struct nftnl_expr_fwd),
160  .nftnl_max_attr = __NFTNL_EXPR_FWD_MAX - 1,
161  .attr_policy = fwd_attr_policy,
162  .set = nftnl_expr_fwd_set,
163  .get = nftnl_expr_fwd_get,
164  .parse = nftnl_expr_fwd_parse,
165  .build = nftnl_expr_fwd_build,
166  .output = nftnl_expr_fwd_snprintf,
167 };