libnftnl  1.2.0
common.c
1 /*
2  * (C) 2012-2013 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 <stdlib.h>
11 #include <sys/socket.h>
12 #include <time.h>
13 #include <linux/netlink.h>
14 #include <linux/netfilter/nfnetlink.h>
15 #include <linux/netfilter/nf_tables.h>
16 
17 #include <libmnl/libmnl.h>
18 #include <libnftnl/common.h>
19 #include <libnftnl/set.h>
20 
21 #include <errno.h>
22 #include "internal.h"
23 
24 static struct nlmsghdr *__nftnl_nlmsg_build_hdr(char *buf, uint16_t type,
25  uint16_t family,
26  uint16_t flags, uint32_t seq,
27  uint16_t res_id)
28 {
29  struct nlmsghdr *nlh;
30  struct nfgenmsg *nfh;
31 
32  nlh = mnl_nlmsg_put_header(buf);
33  nlh->nlmsg_type = type;
34  nlh->nlmsg_flags = NLM_F_REQUEST | flags;
35  nlh->nlmsg_seq = seq;
36 
37  nfh = mnl_nlmsg_put_extra_header(nlh, sizeof(struct nfgenmsg));
38  nfh->nfgen_family = family;
39  nfh->version = NFNETLINK_V0;
40  nfh->res_id = res_id;
41 
42  return nlh;
43 }
44 
45 EXPORT_SYMBOL(nftnl_nlmsg_build_hdr);
46 struct nlmsghdr *nftnl_nlmsg_build_hdr(char *buf, uint16_t type, uint16_t family,
47  uint16_t flags, uint32_t seq)
48 {
49  return __nftnl_nlmsg_build_hdr(buf, (NFNL_SUBSYS_NFTABLES << 8) | type,
50  family, flags, seq, 0);
51 }
52 
53 EXPORT_SYMBOL(nftnl_parse_err_alloc);
54 struct nftnl_parse_err *nftnl_parse_err_alloc(void)
55 {
56  struct nftnl_parse_err *err;
57 
58  err = calloc(1, sizeof(struct nftnl_parse_err));
59  if (err == NULL)
60  return NULL;
61 
62  err->error = NFTNL_PARSE_EOPNOTSUPP;
63 
64  return err;
65 }
66 
67 EXPORT_SYMBOL(nftnl_parse_err_free);
68 void nftnl_parse_err_free(struct nftnl_parse_err *err)
69 {
70  xfree(err);
71 }
72 
73 EXPORT_SYMBOL(nftnl_parse_perror);
74 int nftnl_parse_perror(const char *msg, struct nftnl_parse_err *err)
75 {
76  switch (err->error) {
77  case NFTNL_PARSE_EBADINPUT:
78  return fprintf(stderr, "%s: Bad input format in line %d column %d\n",
79  msg, err->line, err->column);
80  case NFTNL_PARSE_EMISSINGNODE:
81  return fprintf(stderr, "%s: Node \"%s\" not found\n",
82  msg, err->node_name);
83  case NFTNL_PARSE_EBADTYPE:
84  return fprintf(stderr, "%s: Invalid type in node \"%s\"\n",
85  msg, err->node_name);
86  case NFTNL_PARSE_EOPNOTSUPP:
87  return fprintf(stderr, "%s: Operation not supported\n", msg);
88  default:
89  return fprintf(stderr, "%s: Undefined error\n", msg);
90  }
91 }
92 
93 EXPORT_SYMBOL(nftnl_batch_begin);
94 struct nlmsghdr *nftnl_batch_begin(char *buf, uint32_t seq)
95 {
96  return __nftnl_nlmsg_build_hdr(buf, NFNL_MSG_BATCH_BEGIN, AF_UNSPEC,
97  0, seq, NFNL_SUBSYS_NFTABLES);
98 }
99 
100 EXPORT_SYMBOL(nftnl_batch_end);
101 struct nlmsghdr *nftnl_batch_end(char *buf, uint32_t seq)
102 {
103  return __nftnl_nlmsg_build_hdr(buf, NFNL_MSG_BATCH_END, AF_UNSPEC,
104  0, seq, NFNL_SUBSYS_NFTABLES);
105 }
106 
107 EXPORT_SYMBOL(nftnl_batch_is_supported);
108 int nftnl_batch_is_supported(void)
109 {
110  struct mnl_socket *nl;
111  struct mnl_nlmsg_batch *b;
112  char buf[MNL_SOCKET_BUFFER_SIZE];
113  uint32_t seq = time(NULL), req_seq;
114  int ret;
115 
116  nl = mnl_socket_open(NETLINK_NETFILTER);
117  if (nl == NULL)
118  return -1;
119 
120  if (mnl_socket_bind(nl, 0, MNL_SOCKET_AUTOPID) < 0)
121  return -1;
122 
123  b = mnl_nlmsg_batch_start(buf, sizeof(buf));
124 
125  nftnl_batch_begin(mnl_nlmsg_batch_current(b), seq++);
126  mnl_nlmsg_batch_next(b);
127 
128  req_seq = seq;
129  nftnl_set_nlmsg_build_hdr(mnl_nlmsg_batch_current(b),
130  NFT_MSG_NEWSET, AF_INET,
131  NLM_F_ACK, seq++);
132  mnl_nlmsg_batch_next(b);
133 
134  nftnl_batch_end(mnl_nlmsg_batch_current(b), seq++);
135  mnl_nlmsg_batch_next(b);
136 
137  ret = mnl_socket_sendto(nl, mnl_nlmsg_batch_head(b),
138  mnl_nlmsg_batch_size(b));
139  if (ret < 0)
140  goto err;
141 
142  mnl_nlmsg_batch_stop(b);
143 
144  ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
145  while (ret > 0) {
146  ret = mnl_cb_run(buf, ret, req_seq, mnl_socket_get_portid(nl),
147  NULL, NULL);
148  if (ret <= 0)
149  break;
150 
151  ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
152  }
153  mnl_socket_close(nl);
154 
155  /* We're sending an incomplete message to see if the kernel supports
156  * set messages in batches. EINVAL means that we sent an incomplete
157  * message with missing attributes. The kernel just ignores messages
158  * that we cannot include in the batch.
159  */
160  return (ret == -1 && errno == EINVAL) ? 1 : 0;
161 err:
162  mnl_nlmsg_batch_stop(b);
163  return -1;
164 }