libnl  3.2.24-rc1
nf-log.c
1 /*
2  * src/nf-log.c Monitor netfilter log events
3  *
4  * This library is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation version 2.1
7  * of the License.
8  *
9  * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
10  * Copyright (c) 2007 Philip Craig <philipc@snapgear.com>
11  * Copyright (c) 2007 Secure Computing Corporation
12  */
13 
14 #include <netlink/cli/utils.h>
15 #include <netlink/cli/link.h>
16 #include <linux/netfilter/nfnetlink_log.h>
17 #include <netlink/netfilter/nfnl.h>
18 #include <netlink/netfilter/log.h>
19 
20 static struct nfnl_log *alloc_log(void)
21 {
22  struct nfnl_log *log;
23 
24  log = nfnl_log_alloc();
25  if (!log)
26  nl_cli_fatal(ENOMEM, "Unable to allocate log object");
27 
28  return log;
29 }
30 
31 static void obj_input(struct nl_object *obj, void *arg)
32 {
33  struct nl_dump_params dp = {
35  .dp_fd = stdout,
36  .dp_dump_msgtype = 1,
37  };
38 
39  nl_object_dump(obj, &dp);
40 }
41 
42 static int event_input(struct nl_msg *msg, void *arg)
43 {
44  if (nl_msg_parse(msg, &obj_input, NULL) < 0)
45  fprintf(stderr, "<<EVENT>> Unknown message type\n");
46 
47  /* Exit nl_recvmsgs_def() and return to the main select() */
48  return NL_STOP;
49 }
50 
51 int main(int argc, char *argv[])
52 {
53  struct nl_sock *nf_sock;
54  struct nl_sock *rt_sock;
55  struct nl_cache *link_cache;
56  struct nfnl_log *log;
57  enum nfnl_log_copy_mode copy_mode;
58  uint32_t copy_range;
59  int err;
60  int family;
61 
62  nf_sock = nl_cli_alloc_socket();
64  nl_socket_modify_cb(nf_sock, NL_CB_VALID, NL_CB_CUSTOM, event_input, NULL);
65 
66  if ((argc > 1 && !strcasecmp(argv[1], "-h")) || argc < 3) {
67  printf("Usage: nf-log family group [ copy_mode ] "
68  "[copy_range] \n");
69  return 2;
70  }
71 
72  nl_cli_connect(nf_sock, NETLINK_NETFILTER);
73 
74  family = nl_str2af(argv[1]);
75  if (family == AF_UNSPEC)
76  nl_cli_fatal(NLE_INVAL, "Unknown family \"%s\": %s",
77  argv[1], nl_geterror(family));
78 
79  nfnl_log_pf_unbind(nf_sock, family);
80  if ((err = nfnl_log_pf_bind(nf_sock, family)) < 0)
81  nl_cli_fatal(err, "Unable to bind logger: %s",
82  nl_geterror(err));
83 
84  log = alloc_log();
85  nfnl_log_set_group(log, atoi(argv[2]));
86 
87  copy_mode = NFNL_LOG_COPY_META;
88  if (argc > 3) {
89  copy_mode = nfnl_log_str2copy_mode(argv[3]);
90  if (copy_mode < 0)
91  nl_cli_fatal(copy_mode,
92  "Unable to parse copy mode \"%s\": %s",
93  argv[3], nl_geterror(copy_mode));
94  }
95  nfnl_log_set_copy_mode(log, copy_mode);
96 
97  copy_range = 0xFFFF;
98  if (argc > 4)
99  copy_range = atoi(argv[4]);
100  nfnl_log_set_copy_range(log, copy_range);
101 
102  if ((err = nfnl_log_create(nf_sock, log)) < 0)
103  nl_cli_fatal(err, "Unable to bind instance: %s",
104  nl_geterror(err));
105 
106  {
107  struct nl_dump_params dp = {
109  .dp_fd = stdout,
110  .dp_dump_msgtype = 1,
111  };
112 
113  printf("log params: ");
114  nl_object_dump((struct nl_object *) log, &dp);
115  }
116 
117  rt_sock = nl_cli_alloc_socket();
118  nl_cli_connect(rt_sock, NETLINK_ROUTE);
119  link_cache = nl_cli_link_alloc_cache(rt_sock);
120 
121  while (1) {
122  fd_set rfds;
123  int nffd, rtfd, maxfd, retval;
124 
125  FD_ZERO(&rfds);
126 
127  maxfd = nffd = nl_socket_get_fd(nf_sock);
128  FD_SET(nffd, &rfds);
129 
130  rtfd = nl_socket_get_fd(rt_sock);
131  FD_SET(rtfd, &rfds);
132  if (maxfd < rtfd)
133  maxfd = rtfd;
134 
135  /* wait for an incoming message on the netlink nf_socket */
136  retval = select(maxfd+1, &rfds, NULL, NULL, NULL);
137 
138  if (retval) {
139  if (FD_ISSET(nffd, &rfds))
140  nl_recvmsgs_default(nf_sock);
141  if (FD_ISSET(rtfd, &rfds))
142  nl_recvmsgs_default(rt_sock);
143  }
144  }
145 
146  return 0;
147 }