add sniff_interface as an input argument to pcapd

pelab/stub/stub-pcap.c

@@ -398,8 +398,11 @@ void init_pcap(int to_ms) {
     char string_filter[128];
     //struct in_addr addr;
 
-//    dev = "vnet"; //"eth0"; //
-    dev = "eth1";
+    dev = sniff_interface; //input parameter of stubd, should be "vnet" or "eth0"
+    if (flag_debug) {
+      printf("The sniff_interface: %s \n", sniff_interface);
+    }
+
     /* ask pcap for the network address and mask of the device */
     pcap_lookupnet(dev,&netp,&maskp,errbuf);
     //For an unknown reason, netp has the wrong 4th number

pelab/stub/stub.h

@@ -73,6 +73,7 @@ typedef struct loss_record loss_record;
 
 extern short  flag_debug;
 extern int pcapfd;
+extern char sniff_interface[128];
 extern connection rcvdb[CONCURRENT_RECEIVERS];
 extern sniff_path sniff_rcvdb[CONCURRENT_RECEIVERS];
 extern unsigned long delays[CONCURRENT_RECEIVERS]; //delay is calculated at the sender side

pelab/stub/stubd.c

@@ -13,6 +13,7 @@ void clean_exit(int);
 
 //Global  
 short  flag_debug;
+char sniff_interface[128];
 connection rcvdb[CONCURRENT_RECEIVERS];
 unsigned long delays[CONCURRENT_RECEIVERS]; //delay is calculated at the sender side
 unsigned long last_delays[CONCURRENT_RECEIVERS];
@@ -514,7 +515,7 @@ int have_time(struct timeval *start_tvp, struct timeval *left_tvp){
   return 0;
 }
 
-int main(void) {
+int main(int argc, char *argv[]) {
   int sockfd_snd, sockfd_rcv_sender, sockfd_rcv_monitor, sockfd_monitor=-1;  
   struct sockaddr_in my_addr;	// my address information
   struct sockaddr_in their_addr; // connector's address information
@@ -532,6 +533,18 @@ int main(void) {
   else 
     flag_debug=0;
 
+  if (argc != 2) {
+    fprintf(stderr,"Usage: stubd <sniff-interface>\n");
+    exit(1);
+  }
+  if (strlen(argv[1]) > 127) {
+    fprintf(stderr,"Error: the <sniff-interface> name must be less than 127 characters \n");
+    exit(1);
+  }
+
+  strcpy(sniff_interface, argv[1]);
+
+
   //set up the sender connection listener
   if ((sockfd_rcv_sender = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
     perror("socket");