libnl  3.3.0
nl-monitor.c
1 /*
2  * src/nl-monitor.c Monitor 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) 2003-2009 Thomas Graf <tgraf@suug.ch>
10  */
11 
12 #include <netlink/cli/utils.h>
13 #include <netlink/cli/link.h>
14 
15 #include <linux/rtnetlink.h>
16 
17 static void obj_input(struct nl_object *obj, void *arg)
18 {
19  struct nl_dump_params dp = {
21  .dp_fd = stdout,
22  .dp_dump_msgtype = 1,
23  };
24 
25  nl_object_dump(obj, &dp);
26 }
27 
28 static int event_input(struct nl_msg *msg, void *arg)
29 {
30  if (nl_msg_parse(msg, &obj_input, NULL) < 0)
31  fprintf(stderr, "<<EVENT>> Unknown message type\n");
32 
33  /* Exit nl_recvmsgs_def() and return to the main select() */
34  return NL_STOP;
35 }
36 
37 int main(int argc, char *argv[])
38 {
39  struct nl_sock *sock;
40  int err = 1;
41  int i, idx;
42 
43  static const struct {
44  enum rtnetlink_groups gr_id;
45  const char* gr_name;
46  } known_groups[] = {
47  { RTNLGRP_LINK, "link" },
48  { RTNLGRP_NOTIFY, "notify" },
49  { RTNLGRP_NEIGH, "neigh" },
50  { RTNLGRP_TC, "tc" },
51  { RTNLGRP_IPV4_IFADDR, "ipv4-ifaddr" },
52  { RTNLGRP_IPV4_MROUTE, "ipv4-mroute" },
53  { RTNLGRP_IPV4_ROUTE, "ipv4-route" },
54  { RTNLGRP_IPV6_IFADDR, "ipv6-ifaddr" },
55  { RTNLGRP_IPV6_MROUTE, "ipv6-mroute" },
56  { RTNLGRP_IPV6_ROUTE, "ipv6-route" },
57  { RTNLGRP_IPV6_IFINFO, "ipv6-ifinfo" },
58  { RTNLGRP_DECnet_IFADDR, "decnet-ifaddr" },
59  { RTNLGRP_DECnet_ROUTE, "decnet-route" },
60  { RTNLGRP_IPV6_PREFIX, "ipv6-prefix" },
61  { RTNLGRP_NONE, NULL }
62  };
63 
64  sock = nl_cli_alloc_socket();
66  nl_socket_modify_cb(sock, NL_CB_VALID, NL_CB_CUSTOM, event_input, NULL);
67 
68  if (argc > 1 && !strcasecmp(argv[1], "-h")) {
69  printf("Usage: nl-monitor [<groups>]\n");
70 
71  printf("Known groups:");
72  for (i = 0; known_groups[i].gr_id != RTNLGRP_NONE; i++)
73  printf(" %s", known_groups[i].gr_name);
74  printf("\n");
75  return 2;
76  }
77 
78  nl_cli_connect(sock, NETLINK_ROUTE);
79 
80  for (idx = 1; argc > idx; idx++) {
81  for (i = 0; known_groups[i].gr_id != RTNLGRP_NONE; i++) {
82  if (!strcmp(argv[idx], known_groups[i].gr_name)) {
83 
84  if ((err = nl_socket_add_membership(sock, known_groups[i].gr_id)) < 0) {
85  nl_cli_fatal(err, "%s: %s\n", argv[idx],
86  nl_geterror(err));
87  }
88 
89  break;
90  }
91  }
92  if (known_groups[i].gr_id == RTNLGRP_NONE)
93  fprintf(stderr, "Warning: Unknown group: %s\n", argv[idx]);
94  }
95 
96  nl_cli_link_alloc_cache(sock);
97 
98  while (1) {
99  fd_set rfds;
100  int fd, retval;
101 
102  fd = nl_socket_get_fd(sock);
103 
104  FD_ZERO(&rfds);
105  FD_SET(fd, &rfds);
106  /* wait for an incoming message on the netlink socket */
107  retval = select(fd+1, &rfds, NULL, NULL, NULL);
108 
109  if (retval) {
110  /* FD_ISSET(fd, &rfds) will be true */
111  nl_recvmsgs_default(sock);
112  }
113  }
114 
115  return 0;
116 }
Customized handler specified by the user.
Definition: handlers.h:83
int nl_socket_get_fd(const struct nl_sock *sk)
Return the file descriptor of the backing socket.
Definition: socket.c:583
enum nl_dump_type dp_type
Specifies the type of dump that is requested.
Definition: types.h:38
Stop parsing altogether and discard remaining messages.
Definition: handlers.h:68
int nl_socket_modify_cb(struct nl_sock *sk, enum nl_cb_type type, enum nl_cb_kind kind, nl_recvmsg_msg_cb_t func, void *arg)
Modify the callback handler associated with the socket.
Definition: socket.c:770
void nl_object_dump(struct nl_object *obj, struct nl_dump_params *params)
Dump this object according to the specified parameters.
Definition: object.c:288
void nl_socket_disable_seq_check(struct nl_sock *sk)
Disable sequence number checking.
Definition: socket.c:282
int nl_recvmsgs_default(struct nl_sock *sk)
Receive a set of message from a netlink socket using handlers in nl_sock.
Definition: nl.c:1093
Message is valid.
Definition: handlers.h:95
void nl_cli_fatal(int err, const char *fmt,...)
Print error message and quit application.
Definition: utils.c:71
Dumping parameters.
Definition: types.h:33
Dump all attributes including statistics.
Definition: types.h:24