void interrupt timer0(void)
{
RC0 = 1;
if (T0IF==1)
{
TMR0 = timer_ini;
receive0();
receive2();
receive1();
if (sending==0) CheckIfSomethingToBeSent();
cpt_led++;
T0IF = 0;
}
if (TXIF==1)
{
TXIF=0;
CheckIfSomethingToBeSent();
}
TODO
//JM RAIF=0;
EEIF=0;
RC0 = 0;
}
int main(int argc, char *argv[])
{
int sockfd;
struct addrinfo hints, *servinfo, *p;
int rv;
int numbytes;
struct sockaddr_storage their_addr;
char buf[MAXBUFLEN+HEADERSIZE];
socklen_t addr_len;
char s[INET6_ADDRSTRLEN];
int cwnd;
double pl, pc;
// extract argument parameters
if (argc != 5)
{
fprintf(stderr,"usage: receiver <portnumber> <CWnd> <Pl> <Pc>\n");
exit(1);
}
char *port = argv[1];
cwnd = atoi(argv[2]);
pl = atof(argv[3]);
pc = atof(argv[4]);
if(pl < 0 || pc < 0 || pl > 1 || pc > 1)
{
fprintf(stderr,"Pl and Pc must be between 0 and 1!\n");
exit(1);
}
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC; // set to AF_INET to force IPv4
hints.ai_socktype = SOCK_DGRAM;
hints.ai_flags = AI_PASSIVE; // use my IP
if ((rv = getaddrinfo(NULL, port, &hints, &servinfo)) != 0)
{
fprintf(stderr, "getaddrinfo: %s\n", gai_strerror(rv));
return 1;
}
// loop through all the results and bind to the first we can
for(p = servinfo; p != NULL; p = p->ai_next)
{
if ((sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1)
{
perror("sender: socket");
continue;
}
if (bind(sockfd, p->ai_addr, p->ai_addrlen) == -1)
{
close(sockfd);
perror("sender: bind");
continue;
}
break;
}
if (p == NULL)
{
fprintf(stderr, "Error: sender failed to bind socket\n");
return 2;
}
freeaddrinfo(servinfo);
printf("Waiting for requested filename...\n");
addr_len = sizeof their_addr;
if ((numbytes = recvfrom(sockfd, buf, MAXBUFLEN-1 , 0, (struct sockaddr *)&their_addr, &addr_len)) == -1)
{
printf("Error: failed to receive filename\n");
exit(1);
}
printf("Received filename from %s\n", inet_ntop(their_addr.ss_family, get_in_addr((struct sockaddr *)&their_addr), s, sizeof s));
buf[numbytes] = '\0';
printf("Requested filename: \"%s\"\n", buf);
// buf contains requested file name; if it exists, send back packets (up to 1 KB at a time) to receiver
// create source buffer to fopen and fread designated file
char *source = NULL;
char sourcePacket[MAXBUFLEN+HEADERSIZE];
FILE *fp = fopen(buf, "r");
size_t sourceLength;
if (fp==NULL)
{
// send any packet with seq=0 and fin=1 to represent no file found
send2(sockfd, buf, strlen(buf), (struct sockaddr *)&their_addr, addr_len, 0, 0, 1, 0, 0, 0);
printf("Error: file not found!\n");
exit(1);
}
if (fseek(fp, 0L, SEEK_END) == 0)
{
// set fsize to file size
long fsize = ftell(fp);
if (fsize == -1)
{
// send any packet with seq=0 and fin=1 to represent no file found
send2(sockfd, buf, strlen(buf), (struct sockaddr *)&their_addr, addr_len, 0, 0, 1, 0, 0, 0);
printf("Error: file size error!\n");
exit(1);
}
// allocate source buffer to filesize
source = malloc(sizeof(char) * (fsize + 1));
// return to front of file
if (fseek(fp, 0L, SEEK_SET) != 0)
{
// send any packet with seq=0 and fin=1 to represent no file found
send2(sockfd, buf, strlen(buf), (struct sockaddr *)&their_addr, addr_len, 0, 0, 1, 0, 0, 0);
free(source);
printf("Error: file size error!\n");
exit(1);
}
// set source to file data
sourceLength = fread(source, sizeof(char), fsize, fp);
// check file source for fread errors
if (sourceLength == 0)
{
// send any packet with seq=0 and fin=1 to represent no file found
send2(sockfd, buf, strlen(buf), (struct sockaddr *)&their_addr, addr_len, 0, 0, 1, 0, 0, 0);
free(source);
printf("Error: file reading error!\n");
exit(1);
}
// NULL-terminate the source
source[sourceLength] = '\0';
}
// close file
fclose(fp);
// initialize variables for sending/receiving acks
int seq=0;
int ack=0;
size_t len=0;
short fin=0;
short crc=0;
int expectedAck=0;
int windowPosition=0;
int tempPosition=0;
while(fin!=1)
{
int numPacketsSent = 0;
tempPosition = windowPosition;
// check that more packets need to be sent and we have not exceeded our send window
while(tempPosition<sourceLength && numPacketsSent<cwnd)
{
// determine size (since it may be less than MAXBUFLEN if last packet to be sent)
int size = MAXBUFLEN;
if(sourceLength-tempPosition<MAXBUFLEN)
size = sourceLength-tempPosition;
// create temp array holding data to be sent
char temp[MAXBUFLEN];
bzero(temp, MAXBUFLEN);
memcpy(temp, source+tempPosition, size);
// send packet with headers and data
numbytes = send2(sockfd, temp, size, (struct sockaddr *)&their_addr, addr_len, tempPosition, seq+len, (tempPosition+MAXBUFLEN>=sourceLength), 0, pl, pc);
//printf("Sent packet of %d-bytes\n", size);
if (numbytes == -1)
{
printf("Packet with sequence #%d lost!\n", tempPosition);
}
else if(numbytes == -2)
{
printf("Packet with sequence #%d corrupted!\n", tempPosition);
}
else
printf("Sent %d bytes with sequence #%d\n", numbytes, tempPosition);
// increment position of data to send
tempPosition+=MAXBUFLEN;
// increment number of packets sent this round
numPacketsSent++;
}
int numAcksReceived=0;
// check that acks of packets sent have been received
while(numAcksReceived < numPacketsSent)
{
// initialize variables
fd_set inSet;
struct timeval timeout;
int received;
FD_ZERO(&inSet);
FD_SET(sockfd, &inSet);
// wait for specified time
timeout.tv_sec = WAITS;
timeout.tv_usec = WAITU;
// check for acks
received = select(sockfd+1, &inSet, NULL, NULL, &timeout);
// if timeout and no acks were received, break and maintain window position
if(received < 1)
{
printf("Timed out while waiting for ACK!\n");
break;
}
// otherwise, fetch the ack
numbytes = receive2(sockfd, buf, &len, (struct sockaddr *)&their_addr, &addr_len, &seq, &ack, &fin, &crc);
//printf("got ack with: %d/%d/%d/%d (s/a/f/c)\n", seq, ack, fin, crc);
if(fin == 1)
{
printf("ACK #%d received!\n", ack);
// FIN rides on the back of the last data packet
printf("FIN sent!\n");
// FINACK is guaranteed to arrive; packet loss/corruption disabled
printf("FINACK received!\n");
break;
}
// ignore ack if it's corrupted (we define this as crc == 1); break and maintain window position
if(crc == 1)
{
printf("ACK #%d is corrupted! Ignoring it.\n", ack);
break;
}
// ack is the one we were expecting, so we can increment windowPosition and expect the next ack
// true if ack is at most expectedAck and more than expectedAck-MAXBUFLEN
if(ack > expectedAck && ack <= expectedAck + MAXBUFLEN)
{
printf("ACK #%d received!\n", ack);
numAcksReceived++;
expectedAck += MAXBUFLEN; // expect the next ack (assume it's a MAXBUFLEN-byte packet)
windowPosition += MAXBUFLEN;
}
}
// at this point, if we didn't receive the expected ACK, continue
}
printf("File finished transmitting! Sender terminating...\n");
// free file source and close socket
free(source);
close(sockfd);
return 0;
}
