一个socket只能与一个socket地址绑定即一个socket只能监听一个端口，服务器如果要同时监听多个端口就必须创建多个socket，若在同一个端口监听多个服务也要创建多个socket绑定到这个端口上。现在服务器监听一个端口上的TCP和UDP请求，并将发送来的数据回射到客户端。
服务端程序：
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#include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <assert.h> #include <stdio.h> #include <unistd.h> #include <errno.h> #include <string.h> #include <fcntl.h> #include <stdlib.h> #include <sys/epoll.h> #include <pthread.h> #define MAX_EVENT_NUMBER 1024 //最大事件数目 #define TCP_BUFFER_SIZE 512//TCP缓冲区 #define UDP_BUFFER_SIZE 1024//UDP缓冲区 int setnonblocking( int fd )//设置为非阻塞描述符 { int old_option = fcntl( fd, F_GETFL ); int new_option = old_option | O_NONBLOCK; fcntl( fd, F_SETFL, new_option ); return old_option; } void addfd( int epollfd, int fd )//注册事件 { epoll_event event; event.data.fd = fd; //event.events = EPOLLIN | EPOLLET; event.events = EPOLLIN;//可读事件 epoll_ctl( epollfd, EPOLL_CTL_ADD, fd, &event ); setnonblocking( fd ); } int main( int argc, char* argv[] ) { if( argc <= 2 ) { printf( "usage: %s ip_address port_number\n", basename( argv[0] ) ); return 1; } const char* ip = argv[1]; int port = atoi( argv[2] ); int ret = 0; struct sockaddr_in address;//绑定TCP端口 bzero( &address, sizeof( address ) ); address.sin_family = AF_INET; inet_pton( AF_INET, ip, &address.sin_addr ); address.sin_port = htons( port ); int listenfd = socket( PF_INET, SOCK_STREAM, 0 ); assert( listenfd >= 0 ); ret = bind( listenfd, ( struct sockaddr* )&address, sizeof( address ) ); assert( ret != -1 ); ret = listen( listenfd, 5 ); assert( ret != -1 ); bzero( &address, sizeof( address ) );//绑定UDP端口 address.sin_family = AF_INET; inet_pton( AF_INET, ip, &address.sin_addr ); address.sin_port = htons( port ); int udpfd = socket( PF_INET, SOCK_DGRAM, 0 ); assert( udpfd >= 0 ); ret = bind( udpfd, ( struct sockaddr* )&address, sizeof( address ) ); assert( ret != -1 ); epoll_event events[ MAX_EVENT_NUMBER ]; int epollfd = epoll_create( 5 ); assert( epollfd != -1 ); addfd( epollfd, listenfd );//TCP端口注册事件 addfd( epollfd, udpfd );//UDP端口注册事件 while( 1 ) { int number = epoll_wait( epollfd, events, MAX_EVENT_NUMBER, -1 );//无限期等待事件发生 if ( number < 0 ) { printf( "epoll failure\n" ); break; } for ( int i = 0; i < number; i++ )//EPOLL就绪事件 { int sockfd = events[i].data.fd; if ( sockfd == listenfd )//监听端口监听TCP连接事件 { struct sockaddr_in client_address; socklen_t client_addrlength = sizeof( client_address ); int connfd = accept( listenfd, ( struct sockaddr* )&client_address, &client_addrlength ); addfd( epollfd, connfd ); } else if ( sockfd == udpfd )//UDP连接 { char buf[ UDP_BUFFER_SIZE ]; memset( buf, '\0', UDP_BUFFER_SIZE ); struct sockaddr_in client_address; socklen_t client_addrlength = sizeof( client_address );//客户端地址 //UDP专用接收数据 ret = recvfrom( udpfd, buf, UDP_BUFFER_SIZE-1, 0, ( struct sockaddr* )&client_address, &client_addrlength ); if( ret > 0 ) {//UDP专用发送数据(回射数据) sendto( udpfd, buf, UDP_BUFFER_SIZE-1, 0, ( struct sockaddr* )&client_address, client_addrlength ); } } else if ( events[i].events & EPOLLIN )//TCP连接 { char buf[ TCP_BUFFER_SIZE ]; while( 1 ) { memset( buf, '\0', TCP_BUFFER_SIZE ); ret = recv( sockfd, buf, TCP_BUFFER_SIZE-1, 0 ); if( ret < 0 ) { if( ( errno == EAGAIN ) || ( errno == EWOULDBLOCK ) )//非阻塞出现这种errrno是读取数据完毕 { break; } close( sockfd ); break; } else if( ret == 0 )//关闭连接 { close( sockfd ); } else { send( sockfd, buf, ret, 0 );//回射数据 } } } else { printf( "something else happened \n" ); } } } close( listenfd ); return 0; } |
客户端程序：
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#include<sys/socket.h> #include<netinet/in.h> #include<arpa/inet.h> #include<assert.h> #include<stdio.h> #include<unistd.h> #include<string.h> #include<stdlib.h> #include<iostream> #define BUF_SIZE 1024 using namespace std; int main(int argc,char* argv[]){ if(argc<=2){ cout<<"argc<=2"<<endl; return 1; } const char* ip=argv[1]; int port=atoi(argv[2]); struct sockaddr_in server_address; bzero(&server_address,sizeof(server_address)); server_address.sin_family=AF_INET; inet_pton(AF_INET,ip,&server_address.sin_addr); server_address.sin_port=htons(port); int sockfd=socket(PF_INET,SOCK_STREAM,0); int sockudp=socket(PF_INET,SOCK_DGRAM,0); assert(sockfd>=0); if(connect(sockfd,(struct sockaddr*)&server_address,sizeof(server_address))<0){//TCP数据发送与接收 cout<<"connect error"<<endl; return 1; } else{ const char* tcp="this is TCP data\n"; send(sockfd,tcp,strlen(tcp),0); char buf[BUF_SIZE]; int ret=recv(sockfd,buf,BUF_SIZE-1,0); if(ret<0){ cout<<"recv tcp error"<<endl; } else{ buf[ret+1]='\0'; cout<<ret<<" "<<buf<<endl; } } if(connect(sockudp,(struct sockaddr*)&server_address,sizeof(server_address))<0){//UDP数据发送与接收 cout<<"connect error"<<endl; return 1; } else{ const char* udp="this is UDP data\n"; send(sockudp,udp,strlen(udp),0); char buf[BUF_SIZE]; int ret=recv(sockudp,buf,BUF_SIZE-1,0); if(ret<0){ cout<<"recv udp error"<<endl; } else{ buf[ret+1]='\0'; cout<<ret<<" "<<buf<<endl; } } close(sockfd); return 0; } |
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