unsigned short sd_cal_crc16(unsigned char *ptr, unsigned int len)
{
return cal_crc(ptr, len);
}
int main(int argc, char* argv[]) /* server program called with no argument */
{
int sock_ftps, ftps_addr_len;
int sock_from_troll_m2, from_troll_addr_len;
int sock_ack, ack_addr_len;
unsigned short checksum = 0;
int buflen = 0;
int head = 0;
// int tail = 0;
struct sockaddr_in ftps_addr;
struct sockaddr_in troll_m2_addr;
struct sockaddr_in troll_m1_addr;
struct sockaddr_in ack_addr;
struct hostent *hp;
hp = gethostbyname(argv[1]);
nr_failed_acks = 0;
if(hp == 0)
{
perror("Unknown host");
exit(1);
}
TCPD_MSG tcpd_recv;
TCPD_MSG ack;
TCPD_MSG tcpd_send;
int i = 0;
int j = 0;
//FLAGS
int crc_match = FALSE;
int ack_buffer_flag = FALSE;
int ack_exist = FALSE;
int window_index = 0;
int lowest_seq = 100000;
int lowest_seq_window_index = 0;
fd_set read_fds;
int new_buf_size = SOCK_BUFF_SIZE;
//init window
for(i = 0; i < 20; i++)
{
window_srv[i] = -1;
}
//init ack
for(j = 0; j < 64; j++)
{
ack_buffer[j] = -1;
}
/*create from ftps socket*/
if((sock_ftps = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
perror("opening datagram socket for send to ftps");
exit(1);
}
/*create troll socket*/
if((sock_from_troll_m2 = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
perror("opening datagram socket for recv from troll m2");
exit(1);
}
/* create troll_addr with parameters and bind troll_addr to socket */
troll_m2_addr.sin_family = AF_INET;
troll_m2_addr.sin_port = htons(TCPD_PORT_M1);
troll_m2_addr.sin_addr.s_addr = INADDR_ANY;
if(bind(sock_from_troll_m2, (struct sockaddr *)&troll_m2_addr, sizeof(troll_m2_addr)) < 0) {
perror("Recv(receive from troll socket Bind failed");
exit(2);
}
setsockopt(sock_from_troll_m2, SOL_SOCKET, SO_RCVBUF, &new_buf_size, sizeof(&new_buf_size));
if((sock_ack = socket(AF_INET, SOCK_DGRAM, 0)) < 0) {
perror("opening datagram socket for send ack to tcpd_m2");
exit(1);
}
#ifndef LOCALTEST
troll_m1_addr.sin_family = AF_INET;
troll_m1_addr.sin_port = htons(TROLL_PORT_M1);
troll_m1_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
#else
troll_m1_addr.sin_family = AF_INET;
troll_m1_addr.sin_port = htons(TCPD_PORT_M2);
troll_m1_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
#endif
//Contruct troll header
ack_addr.sin_family = AF_INET;
ack_addr.sin_port = htons(TCPD_PORT_M2);
bcopy(hp->h_addr, (void*)&ack_addr.sin_addr, hp->h_length);
ftps_addr.sin_family = AF_INET;
//ftps_addr.sin_port = htons(TCPD_PORT);
ftps_addr.sin_port = htons(TCPD_PORT_FTPS);
ftps_addr.sin_addr.s_addr = inet_addr("127.0.0.1");
//GET LEN FOR RECVFROM
ftps_addr_len=sizeof(struct sockaddr_in);
from_troll_addr_len=sizeof(struct sockaddr_in);
ack_addr_len = sizeof(struct sockaddr_in);
bzero(ack.packet.data, MAXBUF);
// recvfrom(sock_from_troll_m2, (void *)&recv_buffer[head], sizeof(TCPD_MSG), 0, (struct sockaddr *)&troll_m2_addr, &from_troll_addr_len);
FD_ZERO(&read_fds);
FD_SET(sock_from_troll_m2, &read_fds);
while(1)
{
if(select(FD_SETSIZE, &read_fds, NULL, NULL, NULL) < 0)
{
perror("SELECT ERROR");
exit(0);
}
if(FD_ISSET(sock_from_troll_m2, &read_fds))
{
if(recvfrom(sock_from_troll_m2, (void *)&recv_buffer[head], sizeof(TCPD_MSG), 0, (struct sockaddr *)&troll_m2_addr, &from_troll_addr_len) < 0)
{
perror("RECV from troll m2 error");
exit(0);
}
printf("\nRECV FROM TROLL_M2, SEQ:%d\n", recv_buffer[head].packet.seq_num);
if (!is_acceptable_seq(recv_buffer[head].packet.seq_num)) {
printf("OUT OF window BOUND\n");
FD_ZERO(&read_fds);
FD_SET(sock_from_troll_m2,&read_fds);
continue;
}
checksum = cal_crc((void *)&recv_buffer[head].packet, (unsigned char)sizeof(struct packet_data));//CRC
printf("\nCAL CHECKSUM: %u, RECV CHECKSUM: %u\n", checksum, recv_buffer[head].checksum);
if(checksum == recv_buffer[head].checksum)
{
crc_match = TRUE;
ack_buffer_flag = FALSE;//CHECK FOR DUP
//
for(i = 0; i< 64; i++)
{
if(ack_buffer[i] == recv_buffer[head].packet.seq_num)
{
ack_buffer_flag = TRUE;
}
}
//printf("\nACK_BUFFER_FLAG STATUS %d\n", ack_buffer_flag);
//
if(ack_buffer_flag != TRUE)//NOT IN BUFFER
{
ack_exist = FALSE;
for(i = 0; i < 20; i++)
{
//CHECK WHETHER IN WINOW OR NOT
if(window_srv[i] == recv_buffer[head].packet.seq_num)
{
ack_exist = TRUE;
}
}
if(ack_exist == TRUE)
{
printf("\nIN THE WINDOWS, WILL ARRIVE FTPS SOON\n",recv_buffer[head].packet.seq_num);
}
else if(ack_exist == FALSE)//NOT IN WINDOW
{
window_index = recv_buffer[head].packet.seq_num % 20;
// //window_index = recv_buffer[head].packet.seq_num;
window_srv[window_index] = recv_buffer[head].packet.seq_num;
printf("\nWIN SRV [%d]:%d\n",window_index, recv_buffer[head].packet.seq_num);
if(head < 63)
{
head++;
}
else
{
head = 0;//Make buffer back
//
}
}
}//end if ack_flag
else if(ack_buffer_flag == TRUE)
{
printf("\nACK FOR DUPLICATE AGAIN\n");
ack.packet.ack = 1;
ack.packet.ack_seq = recv_buffer[head].packet.seq_num;
ack.tcpd_header = ack_addr;
ack.checksum = cal_crc((void *)&ack.packet, (unsigned char)sizeof(struct packet_data));
//sendto(sock_ack, (void *)&ack, sizeof(TCPD_MSG), 0, (struct sockaddr *)&ack_addr, sizeof(ack_addr));
if(sendto(sock_ack, (void *)&ack, sizeof(TCPD_MSG), 0, (struct sockaddr *)&troll_m1_addr, sizeof(troll_m1_addr)) < 0)
{
perror("send to sock_ack error");
exit(0);
}
printf("\nSEND ACK SEQ %d, TO TROLL M1\n", ack.packet.ack_seq);
}
}
else
{
crc_match = FALSE;//checksum wrong
printf("\nCRC HAVE SOMETHING WRONG\n");
}
//
if(crc_match == TRUE)
// if(1)
{
// printf("\nENTER IF CRC_MATCH\n");
// //find the lowest window seq;
lowest_seq = 100000;
lowest_seq_window_index = -1;
for(i = 0; i < 20; i++)
{
if((window_srv[i] < lowest_seq) && (window_srv[i] != -1))
{
lowest_seq = window_srv[i];
lowest_seq_window_index = i;
}
}
//// lowest_seq = find_min();
//// lowest_seq_window_index = find_min_win_index(lowest_seq);
printf("\nLOWEST_SEQ %d\n", lowest_seq);
printf("\nLASTSENT: %d\n", lastsent);
print_win();
if(lowest_seq == (lastsent + 1))//if lowest in win is to be sent
{
int buffer_index = 0;
for(i = 0; i < 64; i++)
{
if(recv_buffer[i].packet.seq_num == lowest_seq)
{
buffer_index = i;
break;
}
}
//
// // int buffer_index = find_min_buffer(lowest_seq);
if(sendto(sock_ftps, (void *)&recv_buffer[buffer_index], sizeof(TCPD_MSG), 0, (struct sockaddr *)&ftps_addr, sizeof(ftps_addr)) < 0)
{
perror("Send to sock_ftps error");
exit(0);
}
// printf("\nSEND SEQ:%d to ftps\n", recv_buffer[buffer_index].packet.seq_num);
//
lastsent = recv_buffer[buffer_index].packet.seq_num;
printf("[%d]finish bit: %d\n",
recv_buffer[buffer_index].packet.seq_num,
recv_buffer[buffer_index].packet.fin);
if(recv_buffer[buffer_index].packet.fin != 1)
{
ack.packet.ack = 1;
ack.packet.ack_seq = recv_buffer[buffer_index].packet.seq_num;
///////// //lastsent = recv_buffer[buffer_index].packet.seq_num;
// printf("\nLAST SENT: %d\n", lastsent);
// printf("\nACK.PACKET.ACK_SEQ: %d\n", ack.packet.ack_seq);
ack_buffer[pointer] = recv_buffer[buffer_index].packet.seq_num;
printf("\nPTR Value %d; lastsent = %d\n", pointer, lastsent);
pointer = (pointer + 1)%64;
//
// if(pointer < 63)
// {
// pointer++;
// }
// else
// {
// pointer = 0;
// }
//
ack.checksum = cal_crc((void*)&ack.packet, (unsigned char)sizeof(struct packet_data));
// printf("\nACK CHECKSUM %d\n", ack.checksum);
ack.tcpd_header = ack_addr;
#ifdef LOCALTEST
// /sendto(sock_ack, (void *)&ack, sizeof(TCPD_MSG), 0, (struct sockaddr *)&ack_addr, sizeof(ack_addr));
if(ack.packet.ack_seq % 5 == 0)
{
sendto(sock_ack, (void *)&ack, sizeof(TCPD_MSG), 0, (struct sockaddr *)&troll_m1_addr, sizeof(troll_m1_addr));
}
else {
if (nr_failed_acks > 5) {
sendto(sock_ack, (void *)&ack, sizeof(TCPD_MSG), 0, (struct sockaddr *)&troll_m1_addr, sizeof(troll_m1_addr));
}
nr_failed_acks++;
}
#else
sendto(sock_ack, (void *)&ack, sizeof(TCPD_MSG), 0, (struct sockaddr *)&troll_m1_addr, sizeof(troll_m1_addr));
#endif
printf("\nACK SEQ SENT:%d\n", recv_buffer[buffer_index].packet.seq_num);
window_srv[lowest_seq_window_index] = -1;
}//end if fin != 1
else
{
printf("\nRECEIVE FIN!!! seq: %d\n", recv_buffer[buffer_index].packet.seq_num);
sendto(sock_ftps, (void*)&recv_buffer[buffer_index], sizeof(TCPD_MSG), 0, (struct sockaddr *)&ftps_addr, sizeof(ftps_addr));
// //sendto(sock_ftps, (void*)&recv_buffer[buffer_index], sizeof(TCPD_MSG), 0, (struct sockaddr *)&ftps_addr, sizeof(ftps_addr));
ack.tcpd_header = ack_addr;
ack.packet.fin_ack = 1;
ack.packet.ack = 0;
ack.packet.ack_seq = recv_buffer[buffer_index].packet.seq_num;
ack.checksum = cal_crc((void *)&ack.packet, (unsigned char)sizeof(struct packet_data));
window_srv[lowest_seq_window_index] = -1;
strcpy(ack.packet.data, "FIN");
//sendto(sock_ack, (void *)&ack, sizeof(TCPD_MSG), 0, (struct sockaddr *)&ack_addr, sizeof(ack_addr));
sendto(sock_ack, (void *)&ack, sizeof(TCPD_MSG), 0, (struct sockaddr *)&troll_m1_addr, sizeof(troll_m1_addr));
printf("\nFINISH TRANSFER FILE\n");
close(sock_ack);
close(sock_from_troll_m2);
close(sock_ftps);
exit(0);
}
}//END IF LAST SENT
else
{
printf("\nSLEEP FOR WAITING\n");
usleep(100000);
}//END LOW
}
else if(crc_match == FALSE)
{
printf("\nCRC WRONG, RETRANSMIT\n");
}
}
FD_ZERO(&read_fds);
FD_SET(sock_from_troll_m2,&read_fds);
}
}
