void begin(void)
{
/* Main loop: */
while (numiters == -1 || numiters-- > 0)
{
int in = getInput();
int out = doCRC(in);
#ifdef raw
print_int(out);
#else
printf("%d\n", out);
#endif
}
}
int main(int argc, char *argv[]) {
int sd, rc, n, cliLen, done, i, dsize, seq_number, file_created, dropped;
int test_flag, n_send_packets, i2;
FILE *f, *f2;
fd_set rfd;
fd_set c_rfd;
char filename[200];
unsigned short CRC;
struct sockaddr_in cliAddr, servAddr;
struct timeval tv;
struct DataAck Ack;
struct FileData FData, FDataBuffer[5], testFEC;
test_flag = FALSE;
if ( argc == 2 ) {
if ( strcmp(argv[1], "-t") == 0) {
printf ("*********** Test mode enabled ************\n");
test_flag = TRUE;
}
else {
printf ("usage: %s -t \n", argv[0]);
exit(1);
}
}
/* socket creation */
sd=socket(AF_INET, SOCK_DGRAM, 0);
if(sd<0) {
printf("%s: cannot open socket \n",argv[0]);
exit(1);
}
/* bind local server port */
servAddr.sin_family = AF_INET;
servAddr.sin_addr.s_addr = htonl(INADDR_ANY);
servAddr.sin_port = htons(LOCAL_SERVER_PORT);
rc = bind (sd, (struct sockaddr *) &servAddr,sizeof(servAddr));
if(rc<0) {
printf("%s: cannot bind port number %d \n",
argv[0], LOCAL_SERVER_PORT);
exit(1);
}
cliLen = sizeof(cliAddr);
printf("FTWID started\n");
printf("Ready for transmition on port UDP %d\n" ,LOCAL_SERVER_PORT);
/* start receiving data process */
/* calculate size of file descriptors table */
dsize = getdtablesize();
done = FALSE;
tv.tv_sec = 0;
tv.tv_usec = 80000;
seq_number = 1; /* start sequence number */
file_created = FALSE;
bzero( &Ack, sizeof(Ack) );
while ( !(done) ) {
Ack.seq_n = seq_number;
#ifdef DEBUG_MODE
printf ("Waiting for packets in sequence %d\n", seq_number);
#endif
/* receive all packets */
/* test flag case */
if ( test_flag ) n_send_packets = 4;
else n_send_packets = 5; /* to include the FEC */
for ( i = 0; i < n_send_packets; i++ )
{
/* read the data in the socket */
n = recvfrom ( sd, (char *) &FData, sizeof(FData), 0, (struct sockaddr *) &cliAddr, &cliLen);
#ifdef DEBUG_MODE
// printf("Packet number %d, seq %d received\n", FData.packet_n, FData.seq_n);
#endif
#ifdef SHOW_DATA_TRANS
printf("\n\n%s\n\n",FData.data);
#endif
/* Checking for drooped packets */
if ( !(test_flag) )
if ( drop() == 0 ) {
#ifdef DEBUG_MODE
printf ("\nPacket %d, sequence %d drooped by drop\n\n", FData.packet_n, FData.seq_n);
#endif
continue;
}
if ( n < 0 ) {
printf ("Fail to receive data file\n");
exit(1);
}
/* wait for next data packet or timeout */
if ( !(test_flag) )
{
FD_ZERO(&rfd);
FD_SET(sd, &rfd);
c_rfd = rfd;
rc = select ( dsize, &c_rfd, NULL, NULL, &tv );
/* if time out */
if ( rc == 0 ) {
#ifdef DEBUG_MODE
printf ( "Packet number %d, seq %d timed out, skiped\n", i, seq_number);
#endif
continue; /* skip that packet */
}
#ifdef DEBUG_MODE
printf("Processing packet %d, seq %d\n", FData.packet_n, FData.seq_n);
#endif
} /* after obtaining the data */
/* process the data */
/* First check for CRC error */
/* in case of error, skip packet */
/* */
if ( !(test_flag) ) {
CRC = doCRC ( (char *) &FData, sizeof(FData) - sizeof(FData.CRC) );
if ( CRC != FData.CRC ) {
#ifdef DEBUG_MODE
printf ("CRC ERROR.\n\n");
#endif
continue;
}
}
/* */
/* ignore sequence number */
if (test_flag) FData.seq_n = seq_number;
/* if the sequence number is correct */
if ( FData.seq_n == seq_number ) {
/* copy the data into the right buffer */
memcpy ( FDataBuffer[FData.packet_n].p_type, FData.p_type, sizeof(FData.p_type) );
memcpy ( FDataBuffer[FData.packet_n].filename, FData.filename, sizeof(FData.filename) );
memcpy ( FDataBuffer[FData.packet_n].data, FData.data, sizeof(FData.data) );
FDataBuffer[FData.packet_n].file_size = FData.file_size;
FDataBuffer[FData.packet_n].file_mode = FData.file_mode;
FDataBuffer[FData.packet_n].seq_n = FData.seq_n;
FDataBuffer[FData.packet_n].packet_n = FData.packet_n;
FDataBuffer[FData.packet_n].data_size = FData.data_size;
FDataBuffer[FData.packet_n].eof = FData.eof;
/* Update Ack Packet */
if ( FData.packet_n == 0 ) Ack.pck1 = TRUE;
if ( FData.packet_n == 1 ) Ack.pck2 = TRUE;
if ( FData.packet_n == 2 ) Ack.pck3 = TRUE;
if ( FData.packet_n == 3 ) Ack.pck4 = TRUE;
if ( FData.packet_n == 4 ) Ack.fet = TRUE;
}
} /* for each Data packet */
/* after all packets have been sucessfully received or timed out */
/* FET */
/* RE-Create Packet 0 if needed */
if ( !(test_flag ) ){
if ( !Ack.pck1 && Ack.pck2 && Ack.pck3 && Ack.pck4 && Ack.fet ) {
doFEC ( (char *) &FDataBuffer[1], (char *) &FDataBuffer[2], (char *) &FDataBuffer[0], sizeof(FDataBuffer[0]) );
doFEC ( (char *) &FDataBuffer[3], (char *) &FDataBuffer[0], (char *) &FDataBuffer[0], sizeof(FDataBuffer[0]) );
doFEC ( (char *) &FDataBuffer[4], (char *) &FDataBuffer[0], (char *) &FDataBuffer[0], sizeof(FDataBuffer[0]) );
FDataBuffer[0].seq_n = seq_number;
FDataBuffer[0].packet_n = 0;
Ack.pck1 = TRUE;
#ifdef DEBUG_MODE
printf ( "\n******* Recreating packet 1, seq %d from FEC\n", seq_number );
#endif
#ifdef SHOW_DATA_TRANS
printf ("\n\n%s\n\n", FDataBuffer[0].data);
#endif
}
if ( Ack.pck1 && !Ack.pck2 && Ack.pck3 && Ack.pck4 && Ack.fet ) {
doFEC ( (char *) &FDataBuffer[0], (char *) &FDataBuffer[2], (char *) &FDataBuffer[1], sizeof(FDataBuffer[0]) );
doFEC ( (char *) &FDataBuffer[3], (char *) &FDataBuffer[1], (char *) &FDataBuffer[1], sizeof(FDataBuffer[0]) );
doFEC ( (char *) &FDataBuffer[4], (char *) &FDataBuffer[1], (char *) &FDataBuffer[1], sizeof(FDataBuffer[0]) );
FDataBuffer[1].seq_n = seq_number;
FDataBuffer[1].packet_n = 1;
Ack.pck2 = TRUE;
#ifdef SHOW_DATA_TRANS
printf ("\n\n%s\n\n", FDataBuffer[1].data);
#endif
}
if ( Ack.pck1 && Ack.pck2 && !Ack.pck3 && Ack.pck4 && Ack.fet ) {
doFEC ( (char *) &FDataBuffer[0], (char *) &FDataBuffer[1], (char *) &FDataBuffer[2], sizeof(FDataBuffer[2]) );
doFEC ( (char *) &FDataBuffer[3], (char *) &FDataBuffer[2], (char *) &FDataBuffer[2], sizeof(FDataBuffer[2]) );
doFEC ( (char *) &FDataBuffer[4], (char *) &FDataBuffer[2], (char *) &FDataBuffer[2], sizeof(FDataBuffer[2]) );
FDataBuffer[2].seq_n = seq_number;
FDataBuffer[2].packet_n = 2;
Ack.pck3 = TRUE;
#ifdef DEBUG_MODE
printf ( "\n******* Recreating packet 3, seq %d from FEC\n", seq_number );
#endif
#ifdef SHOW_DATA_TRANS
printf ("\n\n%s\n\n", FDataBuffer[2].data);
#endif
}
if ( Ack.pck1 && Ack.pck2 && Ack.pck3 && !Ack.pck4 && Ack.fet ) {
doFEC ( (char *) &FDataBuffer[0], (char *) &FDataBuffer[1], (char *) &FDataBuffer[3], sizeof(FDataBuffer[3]) );
doFEC ( (char *) &FDataBuffer[2], (char *) &FDataBuffer[3], (char *) &FDataBuffer[3], sizeof(FDataBuffer[3]) );
doFEC ( (char *) &FDataBuffer[4], (char *) &FDataBuffer[3], (char *) &FDataBuffer[3], sizeof(FDataBuffer[3]) );
FDataBuffer[3].seq_n = seq_number;
FDataBuffer[3].packet_n = 3;
Ack.pck4 = TRUE;
#ifdef DEBUG_MODE
printf ( "\n******* Recreating packet 4, seq %d from FEC\n", seq_number );
#endif
#ifdef SHOW_DATA_TRANS
printf ("\n\n%s\n\n", FDataBuffer[3].data);
#endif
}
}
/* END FET */
/* send ack for what needs to be re-transmitted that can not be recovered or has problems */
strcpy ( Ack.p_type, P_TYPE_ACK );
if ( Ack.pck1 && Ack.pck2 && Ack.pck3 && Ack.pck4 ) {
#ifdef DEBUG_MODE
printf ("All packets have been ack\n");
#endif
Ack.seq_n = seq_number++;
}
else {
Ack.seq_n = seq_number -1;
}
/* if test flag ignore Acks */
if ( !(test_flag) )
n = sendto(sd, (char *) &Ack, sizeof(Ack), 0, (struct sockaddr *) &cliAddr, sizeof(cliAddr));
#ifdef DEBUG_MODE
printf ("Send Ack seq: %d\n", Ack.seq_n);
#endif
if ( test_flag ) {
Ack.pck1 = 1;
Ack.pck2 = 1;
Ack.pck3 = 1;
Ack.pck4 = 1;
}
/* in case all packets are fine */
if ( Ack.pck1 && Ack.pck2 && Ack.pck3 && Ack.pck4 ) {
/* create file if needed */
if ( !file_created ) {
/* print received message */
printf ("Transmition started from %s : UDP %u\n", inet_ntoa(cliAddr.sin_addr), ntohs(cliAddr.sin_port));
printf ("File name: %s\n", FDataBuffer[0].filename);
printf ("File size: %d\n", FDataBuffer[0].file_size);
printf ("Connection stablished.\n");
strcpy ( filename, FDataBuffer[0].filename );
strcat ( filename, ".sent");
f = fopen ( filename, "w" );
chmod ( filename, FDataBuffer[0].file_mode );
file_created = TRUE;
}
/* write buffers to file */
for ( i = 0; i < 4; i++ ) {
for ( i2 = 0; i2 < 5; i2++ ) {
if ( FDataBuffer[i2].packet_n == i ) {
if ( fwrite( &FDataBuffer[i2].data, 1, FDataBuffer[i2].data_size, f ) < 0 ) {
printf ("Failed to write to file \n");
fclose(f);
}
if (FDataBuffer[i2].eof == 1) done = 1;
break;
}
}
}
bzero( &Ack, sizeof(Ack) );
} /* if all files are fine */
}
printf ("\nFile Transmission done.\n");
fclose(f);
return 0;
}
