udpclient.c.bak

UDP server/client 实现

#include <stdlib.h> 
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <fcntl.h>
#include <ctype.h>
#include <unistd.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include "process.h"

struct dtgram
{
		unsigned short opcode;
		unsigned short block;
		char databuf[512];
};
	
int main(int argc,char *argv[])
{
	int fdSock;
	int iRetSock,iRetFile;
	struct sockaddr_in myAddr,svrAddr;
	struct dtgram obj;
	char szFileName[BUFMAX];
	char * parg[ARGMAX];
	unsigned short * popcode;
	int i;
	FILE *pFile;
	int len = sizeof(svrAddr);
	
	fdSock=socket(AF_INET,SOCK_DGRAM,0);
	myAddr.sin_family=AF_INET;
	myAddr.sin_port=htons(0);
	myAddr.sin_addr.s_addr=htonl(INADDR_ANY);
	bind(fdSock,(struct sockaddr *)&myAddr,sizeof(myAddr));
	/////////////////////
	svrAddr.sin_family=AF_INET;
	if (argc == 2)
		svrAddr.sin_addr.s_addr=inet_addr(argv[2]);
	else 
		if (argc == 1)
			svrAddr.sin_addr.s_addr=inet_addr("192.168.0.5");
		else
			{
				printf("Bad optional! Bye...\n");		
				exit(-1);
			}		
	while (1)
	{
		i = 1;
		svrAddr.sin_port=htons(69);
		printf("tftp:>");
    fgets(szFileName, BUFMAX - 1, stdin);
    if ('\n' == szFileName[0])
      continue;
      
    process(szFileName, parg);
    
    if (strcmp(parg[0], "quit") == 0 || strcmp(parg[0], "exit") == 0)
			break;
			
		if (strcmp(parg[0], "get") == 0 && strlen(parg[1]) > 0)
		{
			obj.opcode = 1;
			popcode = (unsigned short *)obj.databuf;
			*popcode = htons(obj.opcode);
			strcpy(&obj.databuf[2], parg[1]);
			strcpy(&obj.databuf[2 + strlen(parg[1]) + 1], "octet");

			if((pFile = fopen(parg[1],"wb")) == NULL)
			{
				printf("create file %s failed\n",parg[1]);
				exit(-1);
			}
			
			iRetFile = strlen(parg[1]) + strlen("octet") + 4;
			iRetSock=sendto(fdSock,obj.databuf,iRetFile,0,(struct sockaddr *)&svrAddr,len);
			
			if(iRetSock != iRetFile)
			{
				perror("send filename failed");
				close(fdSock);
				fclose(pFile);
				exit(-2);	
			}				//在这个地方最好对发出的读请求是否到达进行确认，因为不排除读请求包丢失的可能
			while(2)
			{
				iRetSock=recvfrom(fdSock,obj.databuf,sizeof(obj.databuf),0,(struct sockaddr *)&svrAddr,&len);
				if(iRetSock<1)
				{
					perror("Recv error");
					break;
				}
				obj.opcode = ntohs(*(unsigned short *)obj.databuf);				
				obj.block = ntohs(*(unsigned short *)(&obj.databuf[2]));
				
				if (obj.opcode == 3)
				{			
						obj.opcode = 4;
						popcode = (unsigned short *)obj.databuf;
						*popcode = htons(obj.opcode);
						
						if (sendto(fdSock,obj.databuf,4,0,(struct sockaddr *)&svrAddr,sizeof(svrAddr)) != 4)
						{
							perror("send ACK failed");
							close(fdSock);
							fclose(pFile);
							exit(-2);	
						}	
					if (obj.block == i)
					{
						fwrite(&obj.databuf[4], iRetSock - 4, 1, pFile);
						
						if ((iRetSock - 4) < 512)
						{
							fclose(pFile);
							break;			//break while(2)
						}
						i++;
					}					
				}
				else
				{
					printf("So bad, The file %s is not exist!\n", parg[1]);		//用于调试
					fclose(pFile);
					unlink(parg[1]);
					break;			//break while(2)
				}
			}
		}
		else
		{
			puts("Bad command!");
			continue;			//continue while(1)
		}
	}
	puts("Bye!");	
	close(fdSock);
	return 0;
}