nettest.cc Source File

00001 // nettest.cc 
00002 //      Test out message delivery between two "Nachos" machines,
00003 //      using the Post Office to coordinate delivery.
00004 //
00005 //      Two caveats:
00006 //        1. Two copies of Nachos must be running, with machine ID's 0 and 1:
00007 //              ./nachos -m 0 -o 1 &
00008 //              ./nachos -m 1 -o 0 &
00009 //
00010 //        2. You need an implementation of condition variables,
00011 //           which is *not* provided as part of the baseline threads 
00012 //           implementation.  The Post Office won't work without
00013 //           a correct implementation of condition variables.
00014 //
00015 // Copyright (c) 1992-1993 The Regents of the University of California.
00016 // All rights reserved.  See copyright.h for copyright notice and limitation 
00017 // of liability and disclaimer of warranty provisions.
00018 
00019 #include "copyright.h"
00020 
00021 #include "system.h"
00022 #include "network.h"
00023 #include "post.h"
00024 #include "interrupt.h"
00025 
00026 // Test out message delivery, by doing the following:
00027 //      1. send a message to the machine with ID "farAddr", at mail box #0
00028 //      2. wait for the other machine's message to arrive (in our mailbox #0)
00029 //      3. send an acknowledgment for the other machine's message
00030 //      4. wait for an acknowledgement from the other machine to our 
00031 //          original message
00032 
00033 void
00034 MailTest(int farAddr)
00035 {
00036     PacketHeader outPktHdr, inPktHdr;
00037     MailHeader outMailHdr, inMailHdr;
00038     char *data = "Hello there!";
00039     char *ack = "Got it!";
00040     char buffer[MaxMailSize];
00041 
00042     // construct packet, mail header for original message
00043     // To: destination machine, mailbox 0
00044     // From: our machine, reply to: mailbox 1
00045     outPktHdr.to = farAddr;             
00046     outMailHdr.to = 0;
00047     outMailHdr.from = 1;
00048     outMailHdr.length = strlen(data) + 1;
00049 
00050     // Send the first message
00051     postOffice->Send(outPktHdr, outMailHdr, data); 
00052 
00053     // Wait for the first message from the other machine
00054     postOffice->Receive(0, &inPktHdr, &inMailHdr, buffer);
00055     printf("Got \"%s\" from %d, box %d\n",buffer,inPktHdr.from,inMailHdr.from);
00056     fflush(stdout);
00057 
00058     // Send acknowledgement to the other machine (using "reply to" mailbox
00059     // in the message that just arrived
00060     outPktHdr.to = inPktHdr.from;
00061     outMailHdr.to = inMailHdr.from;
00062     outMailHdr.length = strlen(ack) + 1;
00063     postOffice->Send(outPktHdr, outMailHdr, ack); 
00064 
00065     // Wait for the ack from the other machine to the first message we sent.
00066     postOffice->Receive(1, &inPktHdr, &inMailHdr, buffer);
00067     printf("Got \"%s\" from %d, box %d\n",buffer,inPktHdr.from,inMailHdr.from);
00068     fflush(stdout);
00069 
00070     // Then we're done!
00071     interrupt->Halt();
00072 }