libnl  3.5.0
nl-monitor.c
1 /* SPDX-License-Identifier: LGPL-2.1-only */
2 /*
3  * src/nl-monitor.c Monitor events
4  *
5  * This library is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Lesser General Public
7  * License as published by the Free Software Foundation version 2.1
8  * of the License.
9  *
10  * Copyright (c) 2003-2009 Thomas Graf <tgraf@suug.ch>
11  */
12 
13 #include <netlink/cli/utils.h>
14 #include <netlink/cli/link.h>
15 
16 #include <linux/rtnetlink.h>
17 
18 static const struct {
19  enum rtnetlink_groups gr_id;
20  const char* gr_name;
21 } known_groups[] = {
22  { RTNLGRP_LINK, "link" },
23  { RTNLGRP_NOTIFY, "notify" },
24  { RTNLGRP_NEIGH, "neigh" },
25  { RTNLGRP_TC, "tc" },
26  { RTNLGRP_IPV4_IFADDR, "ipv4-ifaddr" },
27  { RTNLGRP_IPV4_MROUTE, "ipv4-mroute" },
28  { RTNLGRP_IPV4_ROUTE, "ipv4-route" },
29  { RTNLGRP_IPV6_IFADDR, "ipv6-ifaddr" },
30  { RTNLGRP_IPV6_MROUTE, "ipv6-mroute" },
31  { RTNLGRP_IPV6_ROUTE, "ipv6-route" },
32  { RTNLGRP_IPV6_IFINFO, "ipv6-ifinfo" },
33  { RTNLGRP_DECnet_IFADDR, "decnet-ifaddr" },
34  { RTNLGRP_DECnet_ROUTE, "decnet-route" },
35  { RTNLGRP_IPV6_PREFIX, "ipv6-prefix" },
36  { RTNLGRP_IPV4_NETCONF, "ipv4-netconf" },
37  { RTNLGRP_IPV6_NETCONF, "ipv6-netconf" },
38  { RTNLGRP_MPLS_NETCONF, "mpls-netconf" },
39  { RTNLGRP_NONE, NULL }
40 };
41 
42 static void obj_input(struct nl_object *obj, void *arg)
43 {
44  nl_object_dump(obj, arg);
45 }
46 
47 static int event_input(struct nl_msg *msg, void *arg)
48 {
49  if (nl_msg_parse(msg, &obj_input, arg) < 0)
50  fprintf(stderr, "<<EVENT>> Unknown message type\n");
51 
52  /* Exit nl_recvmsgs_def() and return to the main select() */
53  return NL_STOP;
54 }
55 
56 static void print_usage(void)
57 {
58  int i;
59 
60  printf(
61  "Usage: nl-monitor [OPTION] [<groups>]\n"
62  "\n"
63  "Options\n"
64  " -f, --format=TYPE Output format { brief | details | stats }\n"
65  " -h, --help Show this help.\n"
66  "\n"
67  );
68  printf("Known groups:");
69  for (i = 0; known_groups[i].gr_id != RTNLGRP_NONE; i++)
70  printf(" %s", known_groups[i].gr_name);
71  printf("\n");
72  exit(0);
73 }
74 
75 int main(int argc, char *argv[])
76 {
77  struct nl_dump_params dp = {
79  .dp_fd = stdout,
80  .dp_dump_msgtype = 1,
81  };
82 
83  struct nl_sock *sock;
84  int err = 1;
85  int i, idx;
86 
87  sock = nl_cli_alloc_socket();
89  nl_socket_modify_cb(sock, NL_CB_VALID, NL_CB_CUSTOM, event_input, &dp);
90 
91  for (;;) {
92  int c, optidx = 0;
93  static struct option long_opts[] = {
94  { "format", 1, 0, 'f' },
95  { 0, 0, 0, 0 }
96  };
97 
98  c = getopt_long(argc, argv, "f:h", long_opts, &optidx);
99  if (c == -1)
100  break;
101 
102  switch (c) {
103  case 'f':
104  dp.dp_type = nl_cli_parse_dumptype(optarg);
105  break;
106  default:
107  print_usage();
108  break;
109  }
110  }
111 
112  nl_cli_connect(sock, NETLINK_ROUTE);
113 
114  for (idx = optind; argc > idx; idx++) {
115  for (i = 0; known_groups[i].gr_id != RTNLGRP_NONE; i++) {
116  if (!strcmp(argv[idx], known_groups[i].gr_name)) {
117 
118  if ((err = nl_socket_add_membership(sock, known_groups[i].gr_id)) < 0) {
119  nl_cli_fatal(err, "%s: %s\n", argv[idx],
120  nl_geterror(err));
121  }
122 
123  break;
124  }
125  }
126  if (known_groups[i].gr_id == RTNLGRP_NONE)
127  fprintf(stderr, "Warning: Unknown group: %s\n", argv[idx]);
128  }
129 
130  nl_cli_link_alloc_cache(sock);
131 
132  while (1) {
133  fd_set rfds;
134  int fd, retval;
135 
136  fd = nl_socket_get_fd(sock);
137 
138  FD_ZERO(&rfds);
139  FD_SET(fd, &rfds);
140  /* wait for an incoming message on the netlink socket */
141  retval = select(fd+1, &rfds, NULL, NULL, NULL);
142 
143  if (retval) {
144  /* FD_ISSET(fd, &rfds) will be true */
145  nl_recvmsgs_default(sock);
146  }
147  }
148 
149  return 0;
150 }
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:584
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:771
void nl_object_dump(struct nl_object *obj, struct nl_dump_params *params)
Dump this object according to the specified parameters.
Definition: object.c:289
void nl_socket_disable_seq_check(struct nl_sock *sk)
Disable sequence number checking.
Definition: socket.c:283
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:1094
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:78
Dumping parameters.
Definition: types.h:33
Dump all attributes including statistics.
Definition: types.h:24