服务器模型：
- 循环服务器：服务器在同一时刻只能相应一个客户端的请求.
- 并发服务器：服务器在同一个时刻可以相应多个客户端的请求.
UDP循环服务器：（最基本模式）
socket();
bind(...);
while(true) {
recvfrom(...);
process(...); \\初始化;
sendto(...);
}
TCP循环服务器：（最基本模式） TCP并发服务器：
socket(); scoket();
bind(...); bind(...);
listen(...); listen(...);
while(true){ while(1){
accept(...); accept(...);
process(...); if(fork(...) == 0) {
close(...); process(...);
} close(...);
exit(...);
}
close(...);
}
例子：
\\ TCP并发服务器
#include<string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#define portnumber 3333
int main(int argc, char *argv[])
{
int sockfd,new_fd;
struct sockaddr_in server_addr;
struct sockaddr_in client_addr;
int sin_size;
int nbytes;
char buffer[1024];
if(( sockfd = socket(AF_INET,SOCK_STREAM,0)) ==-1) // AF_INET:IPV4;SOCK_STREAM:TCP
{
fprintf(stderr,"Socketerror:%s\n\a",strerror(errno));
exit(1);
}
bzero(&server_addr,sizeof(structsockaddr_in)); // 初始化,置0
server_addr.sin_family =AF_INET; // Internet
server_addr.sin_addr.s_addr =htonl(INADDR_ANY); //(将本机器上的long数据转化为网络上的long数据)和任何主机通信 //INADDR_ANY表示可以接收任意IP地址的数据，即绑定到所有的IP
//server_addr.sin_addr.s_addr =inet_addr("192.168.1.1"); //用于绑定到一个固定IP,inet_addr用于把数字加格式的ip转化为整形ip
server_addr.sin_port =htons(portnumber); // (将本机器上的short数据转化为网络上的short数据)端口号
if( bind(sockfd, (struct sockaddr*)(&server_addr), sizeof(struct sockaddr)) ==-1)
{
fprintf(stderr,"Binderror:%s\n\a",strerror(errno));
exit(1);
}
if( listen(sockfd,5) == -1)
{
fprintf(stderr,"Listenerror:%s\n\a",strerror(errno));
exit(1);
}
while(1)
{
sin_size = sizeof(structsockaddr_in);
if(( new_fd = accept(sockfd,(struct sockaddr *)(&client_addr),&sin_size)) == -1)
{
fprintf(stderr,"Accepterror:%s\n\a",strerror(errno));
exit(1);
}
fprintf(stderr,"Server getconnection from %s\n",inet_ntoa(client_addr.sin_addr)); //将网络地址转换成.字符串
if(( nbytes =read(new_fd,buffer,1024)) == -1)
{
fprintf(stderr,"ReadError:%s\n",strerror(errno));
exit(1);
}
buffer[nbytes]='\0';
printf("nbytes =%d\n",nbytes);
printf("Server received%s\n",buffer);
close(new_fd);
}
close(sockfd);
exit(0);
}
\\ TCP客户端
#include<stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#define portnumber 3333
int main(int argc, char *argv[])
{
int sockfd;
char buffer[1024];
struct sockaddr_in server_addr;
struct hostent *host;
if(argc!=2)
{
fprintf(stderr,"Usage:%shostname \a\n",argv[0]);
exit(1);
}
if(( host =gethostbyname(argv[1])) == NULL)
{
fprintf(stderr,"Gethostnameerror\n");
exit(1);
}
if(( sockfd = socket(AF_INET,SOCK_STREAM,0)) ==-1) // AF_INET:Internet;SOCK_STREAM:TCP
{
fprintf(stderr,"SocketError:%s\a\n",strerror(errno));
exit(1);
}
bzero(&server_addr,sizeof(server_addr));// 初始化,置0
server_addr.sin_family =AF_INET; // IPV4
server_addr.sin_port =htons(portnumber); //(将本机器上的short数据转化为网络上的short数据)端口号
server_addr.sin_addr = *((struct in_addr*)host->h_addr); // IP地址
if( connect(sockfd, (struct sockaddr*)(&server_addr), sizeof(struct sockaddr)) ==-1)
{
fprintf(stderr,"ConnectError:%s\a\n",strerror(errno));
exit(1);
}
printf("Please input char:\n");
fgets(buffer,1024,stdin);
write(sockfd,buffer,strlen(buffer));
close(sockfd);
exit(0);
}
基础编程的终于全部搞定~~~~爽！！！！哈哈~~
