Merge pull request #8 from 1223421/master

An option for the interface, the most necessary thing for WOL but not…

README.md

@@ -12,14 +12,15 @@ ___
 
 ### Usage
 ```bash
-./WakeOnLAN <mac address>[ <broadcast address>]
+./WakeOnLAN <mac address>[ <broadcast address>][ <interface>]
 ```
 The first parameter is the mac address of the target (usually your's network card's mac address).
 The second parameter is optional and defines the broadcast address to send the packet.
+The third parameter is optional and defines the source interface to send the packet from it (not for windows).
 
 Example
 ```bash
-./WakeOnLAN 00:11:22:33:44:55 192.168.1.255
+./WakeOnLAN 00:11:22:33:44:55 192.168.1.255 eth0
 ```
 
 ___

WakeOnLAN.c

@@ -35,6 +35,7 @@
 	#include <netinet/in.h>
 	#include <arpa/inet.h>
 	#include <netdb.h>
+	#include <net/if.h>
 #endif
 #ifdef _WIN32
 	#include <winsock2.h>
@@ -47,6 +48,7 @@
 	#include <sys/socket.h>
 	#include <netinet/in.h>
 	#include <arpa/inet.h>
+	#include <net/if.h>
 #endif
 
 #include <stdio.h>
@@ -99,7 +101,7 @@ int main(int argc, const char* argv[]){
 
 	// If no arguments
 	if(argc < 2){
-		printf("Usage:\n./wakeonlan <mac address> (<broadcast address>)\n");
+		printf("Usage:\n./wakeonlan <mac address> (<broadcast address>) (<interface>)\n");
 		exit(EXIT_FAILURE);
 	}
 
@@ -149,7 +151,15 @@ int main(int argc, const char* argv[]){
 			printf("Failed to bind socket: '%s'.\n", strerror(errno));
 			exit(EXIT_FAILURE);
 		}
-
+		if(argv[3]) {
+			struct ifreq ifr;
+			memset(&ifr, 0, sizeof(ifr));
+			snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s", argv[3]);
+			if (setsockopt(udpSocket, SOL_SOCKET, SO_BINDTODEVICE, (void *)&ifr, sizeof(ifr)) < 0) {
+				printf("Failed to bind interface: '%s'.\n", strerror(errno));
+				exit(EXIT_FAILURE);
+			}
+		}
 		// Set server end point (the broadcast addres)
 		udpServer.sin_family = AF_INET;
 		udpServer.sin_addr.s_addr = inet_addr(broadcastAddress);