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client.c
176 lines (157 loc) · 6.51 KB
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client.c
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#include "myftp.h"
int initCliAddr(int socketfd, int port, char *sendClient,struct sockaddr_in *addr)
{
//Function: Set socketfd with broadcast option and the broadcast address(struct sockaddr_in)
//Hint: Use setsockopt to set broadcast option
int flag=1;
if(setsockopt(socketfd,SOL_SOCKET,SO_BROADCAST,&flag,sizeof(flag))<0){
printf("setsockopt error!\n");
exit(1);
}
addr->sin_family = AF_INET;
addr->sin_port = htons(port);
/*addr->sin_addr.s_addr = htonl(INADDR_BROADCAST);*/
if(inet_aton(sendClient,&(addr->sin_addr)) == 0){
perror("iner_aton");
exit(1);
}
return 0;
}
int findServerAddr(int socketfd, char *filename,const struct sockaddr_in *broadaddr, struct sockaddr_in *servaddr)
{
//Function: Send broadcast message to find server
// Set timeout to wait for server replay
//Hint: Use struct bootServerInfo as boradcast message
// Use setsockopt to set timeout
struct bootServerInfo bootInfo;
/*memcpy(bootInfo.filename,filename,strlen(filename)+1);*/
strcpy(bootInfo.filename,filename);
int len = sizeof(struct sockaddr_in);
if(sendto(socketfd,&bootInfo,sizeof(struct bootServerInfo),0,(struct sockaddr *)broadaddr,len)<0){
printf("sendto error!\n");
exit(1);
}
/*set time out*/
struct timeval timeout = {3,0};
if(setsockopt(socketfd,SOL_SOCKET,SO_RCVTIMEO,(char *)&timeout,sizeof(struct timeval)) != 0){
perror("setsockopt for time out");
exit(1);
}
printf("filename = %s\n",filename);
//receive from server
bzero(servaddr,sizeof(struct sockaddr_in));
int s = recvfrom(socketfd,&bootInfo,sizeof(struct bootServerInfo),MSG_WAITALL,(struct sockaddr*)servaddr,&len);
if(s == -1){
printf("receive server response time out!!\n");
exit(1);
}
else{
printf("find myftpServer IP : %s\n",bootInfo.servAddr);
if(bootInfo.filename[0] != '\0'){
printf("Myftp connent Port:%d\n",bootInfo.connectPort);
servaddr->sin_port = htons(bootInfo.connectPort);
/*printf("serv port = %d\n",ntohs(servaddr->sin_port));*/
}
else if(bootInfo.filename[0] == '\0'){
printf("No filename \"%s\" in the myftpServer\n",filename);
exit(1);
}
}
return 0;
}
int startMyftpClient(struct sockaddr_in *servaddr, const char *filename)
{
int socketfd;
if((socketfd= socket(AF_INET,SOCK_DGRAM,0))<0){
perror("Socket Error!");
exit(1);
}
/*set time out*/
struct timeval timeout = {3,0};
if(setsockopt(socketfd,SOL_SOCKET,SO_RCVTIMEO,(char *)&timeout,sizeof(struct timeval)) != 0){
perror("setsockopt for time out");
exit(1);
}
struct myFtphdr *packet_FRQ;
int f_len = strlen(filename)+1;
int FRQ_size = f_len+4;
packet_FRQ =(struct myFtphdr *)malloc(FRQ_size);
bzero(packet_FRQ,FRQ_size);
packet_FRQ->mf_opcode = htons(FRQ);
packet_FRQ->mf_cksum=htons(0);
strcpy(packet_FRQ->mf_filename,filename);
packet_FRQ->mf_cksum=in_cksum((unsigned short *)packet_FRQ,FRQ_size);
if(sendto(socketfd,packet_FRQ,FRQ_size,0,(struct sockaddr *)servaddr,sizeof(struct sockaddr_in)) == -1){
exit(1);
}
FILE *fin;
char recv_file[FNAMELEN];
sprintf(recv_file,"client_%s",filename);
fin=fopen(recv_file,"wb");
//Function: Get file
printf("file transmission start!!\n");
printf("get file : <%s> from IP:%s\n",filename,inet_ntoa(servaddr->sin_addr));
//data packet
struct myFtphdr *data_packet;
int data_packet_size = MFMAXDATA+6;
data_packet = (struct myFtphdr *)malloc(data_packet_size);
//ACK and ERROR packet
struct myFtphdr *ACK_ERROR_packet;
int ACK_ERROR_size = 6;
ACK_ERROR_packet = (struct myFtphdr *)malloc(ACK_ERROR_size);
int sockaddr_len = sizeof(struct sockaddr_in);
int block = 0;
int recv;
while(1){
//MSG_WAITALL
bzero(data_packet,data_packet_size);
if((recv = recvfrom(socketfd,data_packet,data_packet_size,0,(struct sockaddr*)servaddr,&sockaddr_len))<0){
//check the FRQ is arrived or not
if(block == 0){
//if block == 1,this means we have not received the data block 1
//so,the server may not receive FRQ or the block 1 has lost
//FRQ can be regard as request for block 1
printf("time out!! send FRQ packet again\n");
if(sendto(socketfd,packet_FRQ,FRQ_size,0,(struct sockaddr *)servaddr,sizeof(struct sockaddr_in)) == -1){
exit(1);
}
continue;
}
//client has received block 1
printf("time out waiting data,request server to resend\n");
send_packet(socketfd,ACK_ERROR_packet,servaddr,block,ERROR,ACK_ERROR_size);
}
else if(in_cksum((unsigned short *)data_packet,data_packet_size)!=0){
//receive data has error bit
printf("received data checksum error\n");
send_packet(socketfd,ACK_ERROR_packet,servaddr,block,ERROR,ACK_ERROR_size);
}
else if(ntohs(data_packet->mf_opcode) == DATA && ntohs(data_packet->mf_block) == block+1){
printf("receive data for block = %d\n",ntohs(data_packet->mf_block));
int write_bytes = recv-6;
fwrite(data_packet->mf_data,1,write_bytes,fin);
/*printf("write_bytes = %d\n",write_bytes);*/
if(write_bytes<MFMAXDATA){
printf("file transmission finish!!\n");
block = 0;
send_packet(socketfd,ACK_ERROR_packet,servaddr,block,ACK,ACK_ERROR_size);
fclose(fin);
break;
}
else{
//send ACK
block = ntohs(data_packet->mf_block);
send_packet(socketfd,ACK_ERROR_packet,servaddr,block,ACK,ACK_ERROR_size);
printf("send ack = %d\n",block);
if(block == 65534){
block = 1;
}
}
}else if(ntohs(data_packet->mf_opcode) == DATA && ntohs(data_packet->mf_block) != block+1){
//server dose not receive previous ack packet,send again
int previous = ntohs(data_packet->mf_block);
send_packet(socketfd,ACK_ERROR_packet,servaddr,previous,ACK,ACK_ERROR_size);
}
}
return 0;
}