/*
typedef struct {
uint16_t number;
uint8_t data[2];
uint8_t crc[2];
char end;
} packet_t;
long M = 2147483647;
void AddCongestion(char *data, double p)
{
char c, *pointer = data;
int i;
while (*pointer != '\0') {
c = 0x01;
for ( i = 0; i < 8; i++) {
if ((double)random()/M <= p)
*pointer ^= c;
c <<= 1;
}
pointer++;
}
}
*/
int main(int argc, char *argv[]) {
packet_t* packet;
packet->number = 0;
packet->data[0] = 'a';
packet->data[1] = 'b';
uint16_t crc = calculate_CCITT16((uint8_t *) packet, 4, GENERATE_CRC);
packet->crc[0] = (uint8_t)(crc >> 8);
packet->crc[1] = (uint8_t)(crc & 0xFF);
packet->end = '\0';
printf("Packet before introducing error: %d %c%c %02x%02x\n", packet->number, packet->data[0], packet->data[1], packet->crc[0], packet->crc[1]);
double ber = 1.0;
AddCongestion((char *) packet, ber);
packet->data[0] = 'x';
printf("Packet after introducing error: %d %c%c %02x%02x\n", packet->number, packet->data[0], packet->data[1], packet->crc[0], packet->crc[1]);
if (!calculate_CCITT16((char *) packet, 6, CHECK_CRC))
printf("No error!\n");
else
printf("Error!\n");
}
int main(int argc, char** argv)
{
int fd, s, SenderAddr2Len, do_i_take;
int n = 0;
int ack_num = 0;
double probability;
socklen_t SenderAddrLen;
char* buff[8];
char* ack_pack = malloc(3 * sizeof(char));
if(argc == 1)
{
probability = 0.001;
}
else
{
probability = atof(argv[1]);
}
//Configure struct for the sender
SenderAddr.sin_family = AF_INET;
SenderAddr.sin_port = htons(54841);
SenderAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
SenderAddrLen = sizeof(SenderAddr);
//Bind the sender struct to a port to listen
fd = socket(AF_INET, SOCK_STREAM, 0);
bind(fd, (struct sockaddr*)&SenderAddr, SenderAddrLen);
//Listen on the new port
if(DEBUG) printf("Listening\n");
listen(fd, 2);
s = accept(fd, (struct sockaddr*)&SenderAddr2, &SenderAddr2Len);
if(DEBUG) printf("Accepted\n");
int i = 0;
for(;;)
{
n = read(s, buff, 8);
buff[n]="";
if(DEBUG) printf("%s\n", buff);
if(AddCongestion(probability)==1)
{
if(DEBUG) printf("nope\n");
}
else if(AddCongestion(probability)==0)
{
sleep(1);
sprintf(ack_pack, "%d", ack_num);
printf("%s\n", ack_pack);
write(s, ack_pack, sizeof(ack_pack));
ack_num++;
}
}
close(fd);
close(s);
return 0;
}
