dev: Make device_mtu() return size_t

We don't return negative values and the MTU is supposed to be the
(maximum) length of a packet, thus make it of type size_t. Most of the
users in the code store it in size_t already anyway.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

2 files changed, 4 insertions, 3 deletions

diff --git a/dev.c b/dev.c
index 5bbac71..9c7af15 100644
--- a/dev.c
+++ b/dev.c
@@ -112,9 +112,10 @@ int device_address(const char *ifname, int af, struct sockaddr_storage *ss)
 	return ret;
 }
 
-int device_mtu(const char *ifname)
+size_t device_mtu(const char *ifname)
 {
-	int ret, sock, mtu = 0;
+	size_t mtu = 0;
+	int ret, sock;
 	struct ifreq ifr;
 
 	sock = af_socket(AF_INET);
diff --git a/dev.h b/dev.h
index 7bd1fb3..4bfc3f0 100644
--- a/dev.h
+++ b/dev.h
@@ -4,7 +4,7 @@
 #include <sys/socket.h>
 #include "built_in.h"
 
-extern int device_mtu(const char *ifname);
+extern size_t device_mtu(const char *ifname);
 extern int device_address(const char *ifname, int af, struct sockaddr_storage *ss);
 extern int device_ifindex(const char *ifname);
 extern int device_type(const char *ifname);