summaryrefslogtreecommitdiffstats
path: root/netlink-notify.c
blob: a9d14386b77e4adc71ba4e937a166e0c034aea78 (about) (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
/*
 * (C) 2011-2013 by Christian Hesse <mail@eworm.de>
 *
 * This software may be used and distributed according to the terms
 * of the GNU General Public License, incorporated herein by reference.
 */

#include <asm/types.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <ifaddrs.h>
#include <linux/if.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <netinet/in.h>
#include <sys/socket.h>

#include <libnotify/notify.h>

#define PROGNAME	"netlink-notify"

#define MYPROTO NETLINK_ROUTE
#define MYMGRP RTMGRP_IPV4_ROUTE

#define NOTIFICATION_TIMEOUT	10000
#ifndef DEBUG
#define DEBUG	0
#endif

#define ICON_NETWORK_CONNECTED		"netlink-notify-connected"
#define ICON_NETWORK_DISCONNECTED	"netlink-notify-disconnected"

#define TEXT_TOPIC	"Netlink Notification"
#define TEXT_NEWLINK	"Interface <b>%s</b> is <b>%s</b>."
#define TEXT_NEWADDR	"Interface <b>%s</b> is <b>%s</b>,\nnew address <b>%s</b>/%d."
#define TEXT_DELLINK	"An interface has gone away."

#define TEXT_NONE	"(NONE)"

#define CHECK_CONNECTED	IFF_LOWER_UP

char *program;
unsigned int maxinterface = 0;
NotifyNotification ** notification;

/*** newstr_link ***/
char * newstr_link(char *text, char *interface, unsigned int flags) {
	char *notifystr;

	notifystr = malloc(strlen(text) + strlen(interface) + 4);
	sprintf(notifystr, text, interface, (flags & CHECK_CONNECTED) ? "up" : "down");

	return notifystr;
}

/*** newstr_addr ***/
char * newstr_addr(char *text, char *interface, unsigned int flags, unsigned char family, void *ipaddr, unsigned char prefix) {
	char *notifystr;
	char buf[64];

	inet_ntop(family, ipaddr, buf, sizeof(buf));
	notifystr = malloc(strlen(text) + strlen(interface) + strlen(buf));
	sprintf(notifystr, text, interface, (flags & CHECK_CONNECTED) ? "up" : "down", buf, prefix);

	return notifystr;
}

/*** newstr_away ***/
char * newstr_away(char *text) {
	char *notifystr;

	notifystr = malloc(strlen(text));
	sprintf(notifystr, text);

	return notifystr;
}

/*** open_netlink ***/
int open_netlink (void) {
	int sock = socket (AF_NETLINK, SOCK_RAW, MYPROTO);
	struct sockaddr_nl addr;

	memset ((void *) &addr, 0, sizeof (addr));

	if (sock < 0)
		return sock;
	addr.nl_family = AF_NETLINK;
	addr.nl_pid = getpid ();
	addr.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV6_IFADDR;
	if (bind (sock, (struct sockaddr *) &addr, sizeof (addr)) < 0)
		return -1;
	return sock;
}

/*** read_event ***/
int read_event (int sockint, int (*msg_handler) (struct sockaddr_nl *, struct nlmsghdr *)) {
	int status;
	int ret = 0;
	char buf[4096];
	struct iovec iov = { buf, sizeof buf };
	struct sockaddr_nl snl;
	struct msghdr msg = { (void *) &snl, sizeof snl, &iov, 1, NULL, 0, 0 };
	struct nlmsghdr *h;

	status = recvmsg (sockint, &msg, 0);

	if (status < 0) {
		/* Socket non-blocking so bail out once we have read everything */
		if (errno == EWOULDBLOCK || errno == EAGAIN)
			return ret;

		/* Anything else is an error */
		fprintf (stderr, "read_netlink: Error recvmsg: %d\n", status);
		return status;
	}

	if (status == 0)
		fprintf (stderr, "read_netlink: EOF\n");

	/* We need to handle more than one message per 'recvmsg' */
	for (h = (struct nlmsghdr *) buf; NLMSG_OK (h, (unsigned int) status); h = NLMSG_NEXT (h, status)) {
		/* Finish reading */
		if (h->nlmsg_type == NLMSG_DONE)
			return ret;

		/* Message is some kind of error */
		if (h->nlmsg_type == NLMSG_ERROR) {
			fprintf (stderr, "read_netlink: Message is an error - decode TBD\n");
			return -1;
		}

		/* Call message handler */
		if (msg_handler) {
			ret = (*msg_handler) (&snl, h);
			if (ret < 0) {
				fprintf (stderr, "read_netlink: Message hander error %d\n", ret);
				return ret;
			}
		} else {
			fprintf (stderr, "read_netlink: Error NULL message handler\n");
			return -1;
		}
	}

	return ret;
}

/*** msg_handler ***/
static int msg_handler (struct sockaddr_nl *nl, struct nlmsghdr *msg) {
	char *notifystr = NULL;
	unsigned int errcount = 0;
	GError *error = NULL;
	struct ifaddrmsg *ifa;
	struct ifinfomsg *ifi;
	struct rtattr *rth;
	int rtl;
	char name[IFNAMSIZ];

	ifa = (struct ifaddrmsg *) NLMSG_DATA (msg);
	ifi = (struct ifinfomsg *) NLMSG_DATA (msg);

	if_indextoname(ifi->ifi_index, name);

	/* make sure we have alloced memory for the struct array */
	if (maxinterface < ifi->ifi_index) {
		notification = realloc(notification, (ifi->ifi_index + 1) * sizeof(NotifyNotification));
		for(; maxinterface < ifi->ifi_index; maxinterface++)
			notification[maxinterface] = NULL;
	}

	switch (msg->nlmsg_type) {
		/* just return for cases we want to ignore */
		case RTM_NEWADDR:
			rth = IFA_RTA (ifa);
			rtl = IFA_PAYLOAD (msg);
		
			while (rtl && RTA_OK (rth, rtl)) {
				if (rth->rta_type == IFA_LOCAL)
					notifystr = newstr_addr(TEXT_NEWADDR, name, ifi->ifi_flags,
						ifa->ifa_family, RTA_DATA (rth), ifa->ifa_prefixlen);
				rth = RTA_NEXT (rth, rtl);
			}
			if (notifystr == NULL) {
				return 0;
			}
#if DEBUG
			puts (notifystr);
#endif
			break;
		case RTM_DELADDR:
			return 0;
		case RTM_NEWROUTE:
			return 0;
		case RTM_DELROUTE:
			return 0;
		case RTM_NEWLINK:
			notifystr = newstr_link(TEXT_NEWLINK, name, ifi->ifi_flags);
#if DEBUG
			puts (notifystr);
#endif
			break;
		case RTM_DELLINK:
			notifystr = newstr_away(TEXT_DELLINK);
#if DEBUG
			puts (notifystr);
#endif
			break;
		default:
			/* we should not get here... */
			fprintf(stderr, "msg_handler: Unknown netlink nlmsg_type %d\n", msg->nlmsg_type);
			return 0;
	}

	if (notification[ifi->ifi_index] == NULL) {
		notification[ifi->ifi_index] = notify_notification_new(TEXT_TOPIC, notifystr,
			(ifi->ifi_flags & CHECK_CONNECTED ? ICON_NETWORK_CONNECTED : ICON_NETWORK_DISCONNECTED));
		notify_notification_set_category(notification[ifi->ifi_index], PROGNAME);
		notify_notification_set_urgency(notification[ifi->ifi_index], NOTIFY_URGENCY_NORMAL);
	} else
		notify_notification_update(notification[ifi->ifi_index], TEXT_TOPIC, notifystr,
			(ifi->ifi_flags & CHECK_CONNECTED ? ICON_NETWORK_CONNECTED : ICON_NETWORK_DISCONNECTED));

	notify_notification_set_timeout(notification[ifi->ifi_index], NOTIFICATION_TIMEOUT);

	while (!notify_notification_show (notification[ifi->ifi_index], &error)) {
		if (errcount > 1) {
			fprintf(stderr, "%s: Looks like we can not reconnect to notification daemon... Exiting.\n", program);
			exit(EXIT_FAILURE);
		} else {
			g_printerr("%s: Error \"%s\" while trying to show notification. Trying to reconnect.\n", program, error->message);
			errcount++;

			g_error_free (error);
			error = NULL;

			notify_uninit ();

			usleep (500 * 1000);

			if (!notify_init (PROGNAME)) {
				fprintf(stderr, "%s: Can't create notify.\n", program);
				exit(EXIT_FAILURE);
			}
		}
	}
	errcount = 0;
	free(notifystr);

	return 0;
}

/*** main ***/
int main (int argc, char **argv) {
	int nls;

	program = argv[0];
	printf ("%s: %s v%s (compiled: " __DATE__ ", " __TIME__ ")\n", argv[0], PROGNAME, VERSION);

	nls = open_netlink ();
	if (nls < 0) {
		fprintf (stderr, "%s: Error opening netlin socket!", argv[0]);
		exit (EXIT_FAILURE);
	}

	if (!notify_init (PROGNAME)) {
		fprintf (stderr, "%s: Can't create notify.\n", argv[0]);
		exit (EXIT_FAILURE);
	}

	while (1)
		read_event (nls, msg_handler);

	return EXIT_SUCCESS;
}