1 files changed, 33 insertions, 9 deletions

diff --git a/iw_if.c b/iw_if.c
index 72de7b1..8a4fd0e 100644
--- a/iw_if.c
+++ b/iw_if.c
@@ -51,8 +51,9 @@ bool if_is_up(const char *ifname)
 	return ret;
 }
 
-/** Bring @ifname up if not already up. Return 0 if ok, < 0 on error. */
-int if_set_up(const char *ifname)
+
+/** Change the up/down state of @ifname according to @up. */
+static int if_set_up_or_down(const char *ifname, bool up)
 {
 	struct ifreq ifr;
 	int ret, skfd = socket(AF_INET, SOCK_DGRAM, 0);
@@ -64,15 +65,38 @@ int if_set_up(const char *ifname)
 	strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name) - 1);
 
 	ifr.ifr_flags = if_get_flags(skfd, ifname);
-	if (ifr.ifr_flags & IFF_UP)
-		return 0;
-
-	ifr.ifr_flags |= IFF_UP;
+	if (up) {
+		ifr.ifr_flags |= IFF_UP;
+	} else {
+		ifr.ifr_flags &= ~IFF_UP;
+	}
 	ret = ioctl(skfd, SIOCSIFFLAGS, &ifr);
 	close(skfd);
 	return ret;
 }
 
+/** Bring @ifname up. */
+int if_set_up(const char *ifname)
+{
+	return if_set_up_or_down(ifname, true);
+}
+
+/** Set @ifname down. */
+int if_set_down(const char *ifname)
+{
+	return if_set_up_or_down(ifname, false);
+}
+
+/** Exit handler to restore interface 'down' state on exit via atexit(3). */
+void if_set_down_on_exit(void)
+{
+	const char *ifname = conf_ifname();
+
+	if (ifname && if_set_down(ifname) < 0) {
+		err_msg("unable to restore %s interface state - set down manually", ifname);
+	}
+}
+
 /* Interface information */
 void if_getinf(const char *ifname, struct if_info *info)
 {
@@ -87,7 +111,7 @@ void if_getinf(const char *ifname, struct if_info *info)
 
 	info->flags = if_get_flags(skfd, ifname);
 
-	strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
+	strncpy(ifr.ifr_name, ifname, IFNAMSIZ-1);
 	if (ioctl(skfd, SIOCGIFMTU, &ifr) == 0)
 		info->mtu = ifr.ifr_mtu;
 
@@ -163,7 +187,7 @@ void dyn_info_get(struct iw_dyn_info *info, const char *ifname)
 		err_sys("%s: can not open socket", __func__);
 
 	memset(info, 0, sizeof(*info));
-	strncpy(iwr.ifr_name, ifname, IFNAMSIZ);
+	strncpy(iwr.ifr_name, ifname, IFNAMSIZ-1);
 
 	if (ioctl(skfd, SIOCGIWNAME, &iwr) < 0)
 		err_sys("can not open device '%s'", ifname);
@@ -250,7 +274,7 @@ void iw_getinf_range(const char *ifname, struct iw_range *range)
 		err_sys("%s: can not open socket", __func__);
 
 	memset(range, 0, sizeof(struct iw_range));
-	strncpy(iwr.ifr_name, ifname, IFNAMSIZ);
+	strncpy(iwr.ifr_name, ifname, IFNAMSIZ-1);
 
 	iwr.u.data.pointer = (caddr_t) range;
 	iwr.u.data.length  = sizeof(struct iw_range);