stub files for Plab

pelab/stub/Makefile

@@ -2,7 +2,7 @@ all: stubd stub-monitor
 
 stubd: stubd.o stub-pcap.o stub.h
 	gcc -g -Wall -lm -lpcap stubd.o stub-pcap.o -o stubd
-monitor-stub: monitor-stub.c stub.h
+stub-monitor: stub-monitor.c stub.h
 	gcc -g -Wall stub-monitor.c -o stub-monitor
 stubd.o: stubd.c stub.h
 	gcc -g -Wall -c stubd.c 

pelab/stub/stub-pcap.c

@@ -103,6 +103,7 @@ int search_sniff_rcvdb(int path_id, u_long seqnum) {
 void pop_sniff_rcvdb(int path_id, u_long to_seqnum){
   int to_index = search_sniff_rcvdb(path_id, to_seqnum);
   if (to_index != -1) {
+    //if the packet has no payload or the last sent seqnum equals the pop number
     if ((sniff_rcvdb[path_id].records[to_index].seq_end==sniff_rcvdb[path_id].records[to_index].seq_start) 
       || (sniff_rcvdb[path_id].records[to_index].seq_end-1 == to_seqnum)) {
       sniff_rcvdb[path_id].start = (to_index+1)%SNIFF_WINSIZE; //complete pop-up 
@@ -181,7 +182,7 @@ u_int16_t handle_IP(u_char *args, const struct pcap_pkthdr* pkthdr, const u_char
     ip_dst = ip->ip_dst.s_addr;
 
     if (flag_debug){    
-      //For an unknown reason, inet_ntoa returns the same string if called twice in one fprintf
+      //Note:inet_ntoa returns the same string if called twice in one line due to static string buffer
       fprintf(stdout,"IP src:%s ", inet_ntoa(ip->ip_src));
       fprintf(stdout,"dst:%s hlen:%d version:%d len:%d\n",inet_ntoa(ip->ip_dst),hlen,version,len);
     }
@@ -327,7 +328,7 @@ void init_pcap(int to_ms) {
     char string_filter[128];
     //struct in_addr addr;
 
-    dev = "eth0"; //"vnet";
+    dev = "vnet"; //"eth0";
 
     /* ask pcap for the network address and mask of the device */
     pcap_lookupnet(dev,&netp,&maskp,errbuf);

pelab/stub/stubd.c

@@ -232,7 +232,11 @@ int receive_monitor(int sockfd) {
   memcpy(&tmpulong, nextptr, SIZEOF_LONG);
   destnum = ntohl(tmpulong);
 
-  //receive dest addrs
+  //return success if no dest addr is given
+  if (destnum == 0){
+    return 1;
+  }
+  //otherwise, receive dest addrs
   if (recv_all(sockfd, buf, destnum*SIZEOF_LONG)==0) {
     return 0;
   }