（TCP IP网络编程）实验五 I/O复用模型编程
一．实验目的
(1) 理解I/O复用模型的工作原理；
(2) 掌握select函数的功能和调用顺序；
(3) 掌握I/O复用模型服务器编程。
二．实验内容
(1) 在Linux下实现一个以I/O复用模型为基础的回声服务器端(及客户端)；
(2) 在Windows下实现一个以I/O复用模型为基础的回声服务器端(及客户端)。
三．实验过程
（1）实验代码：
echo_selectserv.c:
#include \n" , argv[0]);
exit(1);
}
serv_sock=socket(PF_INET, SOCK_STREAM, 0);
memset(&serv_adr, 0, sizeof(serv_adr));
serv_adr.sin_family=AF_INET;
serv_adr.sin_addr.s_addr=htonl(INADDR_ANY);
serv_adr.sin_port=htons(atoi(argv[1]));
if(bind(serv_sock, (struct sockaddr*) &serv_adr, sizeof(serv_adr))==-1)
error_handling("bind() error");
if(listen(serv_sock, 5)==-1)
error_handling("listen() error");
FD_ZERO(&reads);
FD_SET(serv_sock, &reads);
fd_max=serv_sock;
while(1)
{
cpy_reads=reads;
timeout.tv_sec=5;
timeout.tv_usec=5000;
if((fd_num=select(fd_max+1, &cpy_reads, 0, 0, &timeout))==-1)
break;
if(fd_num==0)
continue;
for(i=0; i<fd_max+1; i++)
{
if(FD_ISSET(i, &cpy_reads))
{
if(i==serv_sock) // connection request!
{
adr_sz=sizeof(clnt_adr);
clnt_sock=
accept(serv_sock, (struct sockaddr*)&clnt_adr, &adr_sz);
FD_SET(clnt_sock, &reads);
if(fd_max<clnt_sock)
fd_max=clnt_sock;
printf("connected client: %d \n", clnt_sock);
}
else // read message!
{
str_len=read(i, buf, BUF_SIZE);
if(str_len==0) // close request!
{
FD_CLR(i, &reads);
close(i);
printf("closed client: %d \n", i);
}
else
{
write(i, buf, str_len); // echo!
}
}
}
}
}
close(serv_sock);
return 0;
}
void error_handling(char *buf)
{
fputs(buf, stderr);
fputc('\n', stderr);
exit(1);
}
echo_client.c:
#include \n" , argv[0]);
exit(1);
}
sock=socket(PF_INET, SOCK_STREAM, 0);
if(sock==-1)
error_handling("socket() error");
memset(&serv_adr, 0, sizeof(serv_adr));
serv_adr.sin_family=AF_INET;
serv_adr.sin_addr.s_addr=inet_addr(argv[1]);
serv_adr.sin_port=htons(atoi(argv[2]));
if(connect(sock, (struct sockaddr*)&serv_adr, sizeof(serv_adr))==-1)
error_handling("connect() error!");
else
puts("Connected...........");
while(1)
{
fputs("Input message(Q to quit): ", stdout);
fgets(message, BUF_SIZE, stdin);
if(!strcmp(message,"q\n") || !strcmp(message,"Q\n"))
break;
write(sock, message, strlen(message));
str_len=read(sock, message, BUF_SIZE-1);
message[str_len]=0;
printf("Message from server: %s", message);
}
close(sock);
return 0;
}
void error_handling(char *message)
{
fputs(message, stderr);
fputc('\n', stderr);
exit(1);
}
结果：
（2）实验代码：
echo_selectserv_win.c:
#include \n" , argv[0]);
exit(1);
}
if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
ErrorHandling("WSAStartup() error!");
hServSock = socket(PF_INET, SOCK_STREAM, 0);
memset(&servAdr, 0, sizeof(servAdr));
servAdr.sin_family = AF_INET;
servAdr.sin_addr.s_addr = htonl(INADDR_ANY);
servAdr.sin_port = htons(atoi(argv[1]));
if (bind(hServSock, (SOCKADDR*)&servAdr, sizeof(servAdr)) == SOCKET_ERROR)
ErrorHandling("bind() error");
if (listen(hServSock, 5) == SOCKET_ERROR)
ErrorHandling("listen() error");
FD_ZERO(&reads);
FD_SET(hServSock, &reads);
while (1)
{
cpyReads = reads;
timeout.tv_sec = 5;
timeout.tv_usec = 5000;
if ((fdNum = select(0, &cpyReads, 0, 0, &timeout)) == SOCKET_ERROR)
break;
if (fdNum == 0)
continue;
for (i = 0; i < reads.fd_count; i++)
{
if (FD_ISSET(reads.fd_array[i], &cpyReads))
{
if (reads.fd_array[i] == hServSock) // connection request!
{
adrSz = sizeof(clntAdr);
hClntSock =
accept(hServSock, (SOCKADDR*)&clntAdr, &adrSz);
FD_SET(hClntSock, &reads);
printf("connected client: %d \n", hClntSock);
}
else // read message!
{
strLen = recv(reads.fd_array[i], buf, BUF_SIZE - 1, 0);
if (strLen == 0) // close request!
{
FD_CLR(reads.fd_array[i], &reads);
closesocket(cpyReads.fd_array[i]);
printf("closed client: %d \n", cpyReads.fd_array[i]);
}
else
{
send(reads.fd_array[i], buf, strLen, 0); // echo!
}
}
}
}
}
closesocket(hServSock);
WSACleanup();
return 0;
}
void ErrorHandling(char* message)
{
fputs(message, stderr);
fputc('\n', stderr);
exit(1);
}
echo_client_win.c:
#include \n" , argv[0]);
exit(1);
}
if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
ErrorHandling("WSAStartup() error!");
hSocket = socket(PF_INET, SOCK_STREAM, 0);
if (hSocket == INVALID_SOCKET)
ErrorHandling("socket() error");
memset(&servAdr, 0, sizeof(servAdr));
servAdr.sin_family = AF_INET;
servAdr.sin_addr.s_addr = inet_addr(argv[1]);
servAdr.sin_port = htons(atoi(argv[2]));
if (connect(hSocket, (SOCKADDR*)&servAdr, sizeof(servAdr)) == SOCKET_ERROR)
ErrorHandling("connect() error!");
else
puts("Connected...........");
while (1)
{
fputs("Input message(Q to quit): ", stdout);
fgets(message, BUF_SIZE, stdin);
if (!strcmp(message, "q\n") || !strcmp(message, "Q\n"))
break;
send(hSocket, message, strlen(message), 0);
strLen = recv(hSocket, message, BUF_SIZE - 1, 0);
message[strLen] = 0;
printf("Message from server: %s", message);
}
closesocket(hSocket);
WSACleanup();
return 0;
}
void ErrorHandling(char* message)
{
fputs(message, stderr);
fputc('\n', stderr);
exit(1);
}
结果：
