4 files changed, 194 insertions, 0 deletions
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..218b07a
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+*~
+*.o
+netlink-notify
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..fbf9ec9
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,12 @@
+# netlink-notify - Notify about netlink changes
+
+CC	:= gcc
+CFLAGS	+= $(shell pkg-config --cflags --libs libmnl) $(shell pkg-config --cflags --libs libnotify)
+VERSION	= $(shell git describe --tags --long)
+
+all: netlink-notify.c
+	$(CC) $(CFLAGS) -o netlink-notify netlink-notify.c \
+		-DVERSION="\"$(VERSION)\""
+
+clean:
+	/bin/rm -f *.o *~ netlink-notify
diff --git a/netlink-notify.c b/netlink-notify.c
new file mode 100644
index 0000000..9679a45
--- /dev/null
+++ b/netlink-notify.c
@@ -0,0 +1,171 @@
+/*
+ * (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 <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+
+#include <libnotify/notify.h>
+
+#include <libmnl/libmnl.h>
+#include <linux/if.h>
+#include <linux/if_link.h>
+#include <linux/rtnetlink.h>
+
+#define PROGNAME	"netlink-notify"
+
+#define NOTIFICATION_TIMEOUT	10000
+#ifndef DEBUG
+#define DEBUG	0
+#endif
+
+#define ICON_NETWORK_ONLINE	"network-transmit-receive"
+#define ICON_NETWORK_OFFLINE	"network-error"
+
+#define TEXT_TOPIC		"Netlink Notification"
+#define TEXT_NOTIFICATION	"Interface <b>%s</b> is <b>%s</b>."
+#define TEXT_NOTIFICATION_DEBUG	"%s: Interface %s (index %d) is %s.\n"
+
+// we need these to be global...
+unsigned int netlinksize = 1; // never use 0 and avoid overwriting the main pointer...
+size_t * notificationref;
+char * program = NULL;
+
+static int data_attr_cb(const struct nlattr * attr, void * data) {
+	const struct nlattr ** tb = data;
+	int type = mnl_attr_get_type(attr);
+
+	if (mnl_attr_type_valid(attr, IFLA_MAX) < 0)
+		return MNL_CB_OK;
+
+	switch(type) {
+		case IFLA_MTU:
+			if (mnl_attr_validate(attr, MNL_TYPE_U32) < 0) {
+				fprintf(stderr, "%s: Invalid netlink attribute.\n", program);
+				return MNL_CB_ERROR;
+			}
+			break;
+		case IFLA_IFNAME:
+			if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0) {
+				fprintf(stderr, "%s: Invalid netlink attribute.\n", program);
+				return MNL_CB_ERROR;
+			}
+			break;
+	}
+	tb[type] = attr;
+	return MNL_CB_OK;
+}
+
+static int data_cb(const struct nlmsghdr * nlh, void * data) {
+	struct nlattr * tb[IFLA_MAX + 1] = {};
+	struct ifinfomsg * ifm = mnl_nlmsg_get_payload(nlh);
+
+	char * notifystr = NULL;
+	const char * interface = NULL;
+	NotifyNotification * notification = NULL;
+	unsigned int errcount = 0;
+
+	gboolean res = FALSE;
+	GError * error = NULL;
+
+	mnl_attr_parse(nlh, sizeof(* ifm), data_attr_cb, tb);
+
+	interface = mnl_attr_get_str(tb[IFLA_IFNAME]);
+	notifystr = malloc(strlen(interface) + strlen(TEXT_NOTIFICATION) + 1); // 2* %s is enough for "down", but we need an additional byte for \n
+	sprintf(notifystr, TEXT_NOTIFICATION, interface, (ifm->ifi_flags & IFF_RUNNING ? "up" : "down"));
+#if DEBUG
+	printf(TEXT_NOTIFICATION_DEBUG, program, interface, ifm->ifi_index, (ifm->ifi_flags & IFF_RUNNING ? "up" : "down"));
+#endif
+
+	if (netlinksize < ifm->ifi_index) {
+		notificationref = realloc(notificationref, (ifm->ifi_index + 1) * sizeof(size_t));
+		while(netlinksize < ifm->ifi_index)
+			notificationref[++netlinksize] = 0;
+	}
+	
+	if (notificationref[ifm->ifi_index] == 0) {
+		notification = notify_notification_new(TEXT_TOPIC, notifystr, (ifm->ifi_flags & IFF_RUNNING ? ICON_NETWORK_ONLINE : ICON_NETWORK_OFFLINE));
+		notificationref[ifm->ifi_index] = (size_t)notification;
+	} else {
+		notification = (NotifyNotification *)notificationref[ifm->ifi_index];
+		notify_notification_update(notification, TEXT_TOPIC, notifystr, (ifm->ifi_flags & IFF_RUNNING ? ICON_NETWORK_ONLINE : ICON_NETWORK_OFFLINE));
+	}
+
+	notify_notification_set_timeout(notification, NOTIFICATION_TIMEOUT);
+	notify_notification_set_category(notification, PROGNAME);
+	notify_notification_set_urgency(notification, NOTIFY_URGENCY_NORMAL);
+
+	while(!notify_notification_show(notification, &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 MNL_CB_OK;
+}
+
+int main(int argc, char ** argv) {
+	struct mnl_socket * nl;
+	char buf[MNL_SOCKET_BUFFER_SIZE];
+	int ret;
+
+	program = argv[0];
+
+	printf("%s: %s v%s (compiled: " __DATE__ ", " __TIME__ ")\n", argv[0], PROGNAME, VERSION);
+
+	if(!notify_init(PROGNAME)) {
+		fprintf(stderr, "%s: Can't create notify.\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	nl = mnl_socket_open(NETLINK_ROUTE);
+	if (!nl) {
+		fprintf(stderr, "%s: Can't create netlink socket.\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	if (mnl_socket_bind(nl, RTMGRP_LINK, MNL_SOCKET_AUTOPID) < 0) {
+		fprintf(stderr, "%s: Can't bind netlink socket.\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
+	while (ret > 0) {
+		ret = mnl_cb_run(buf, ret, 0, 0, data_cb, NULL);
+		if (ret <= 0)
+			break;
+		ret = mnl_socket_recvfrom(nl, buf, sizeof(buf));
+	}
+	if (ret == -1) {
+		fprintf(stderr, "%s: An error occured reading from netlink socket.\n", argv[0]);
+		exit(EXIT_FAILURE);
+	}
+
+	mnl_socket_close(nl);
+
+	return EXIT_SUCCESS;
+}
diff --git a/netlink-notify.desktop b/netlink-notify.desktop
new file mode 100644
index 0000000..6b8e10b
--- /dev/null
+++ b/netlink-notify.desktop
@@ -0,0 +1,8 @@
+[Desktop Entry]
+Name=Netlink Notify
+Icon=network-transmit-receive
+Exec=/usr/bin/netlink-notify
+Terminal=false
+Type=Application
+StartupNotify=false
+Categories=Utility