初识TCP/IP网络编程-编程知识

初识TCP/IP网络编程

学习自《TCP/IP网络编程》

客户端：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
void error_handling(char * message);int main(int argc,char *argv[])
{int sock;struct sockaddr_in serv_addr;char message[30];int str_len;if(argc!=3){printf("Usage : %s <IP> <port>\n",argv[0]);exit(1);}sock=socket(PF_INET,SOCK_STREAM,0);if(sock == -1)error_handling("socket() error");memset(&serv_addr,0,sizeof(serv_addr));serv_addr.sin_family=AF_INET;serv_addr.sin_addr.s_addr=inet_addr(argv[1]);serv_addr.sin_port=htons(atoi(argv[2]));if(connect(sock,(struct sockaddr *)&serv_addr,sizeof(serv_addr))==-1)error_handling("connect() error!");str_len=read(sock,message,sizeof(message)-1);if(str_len==1)error_handling("read() error!");printf("Message from server : %s \n",message);close(sock);return 0;
}void error_handling(char *message)
{fputs(message,stderr);fputc('\n',stderr);exit(1);
}

服务端：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
void error_handling(char * message);int main(int argc,char *argv[])
{int serv_sock;int clnt_sock;struct sockaddr_in serv_addr;struct sockaddr_in clnt_addr;socklen_t clnt_addr_size;char message[]="hello world!";if(argc!=2){printf("Usage: %s <port>\n",argv[0]);exit(1);}serv_sock=socket(PF_INET,SOCK_STREAM,0);if(serv_sock == -1)error_handling("socker() error");memset(&serv_addr,0,sizeof(serv_addr));serv_addr.sin_family=AF_INET;serv_addr.sin_addr.s_addr=htonl(INADDR_ANY);serv_addr.sin_port=htons(atoi(argv[1]));if(bind(serv_sock,(struct sockaddr*)&serv_addr,sizeof(serv_addr))==-1)error_handling("bind() error");if(listen(serv_sock,5)==-1)error_handling("listen() error");clnt_addr_size=sizeof(clnt_addr);clnt_sock=accept(serv_sock,(struct sockaddr*)&clnt_addr,&clnt_addr_size);if(clnt_sock==-1)error_handling("accept() error");write(clnt_sock,message,sizeof(message));close(clnt_sock);close(serv_sock);return 0;
}void error_handling(char *message)
{fputs(message,stderr);fputc('\n',stderr);exit(1);
}

程序在Linux下运行，先启动服务端，再启动客户端

客户端会收到消息：Message from server : hello world!

#include <sys/socket.h>

int socket(int domain,int type,int protocol);

成功时返回文件描述符，失败时返回-1。

#include <sys/socket.h>

int bind(int sockfd,struct sockaddr *myaddr,socklen_t addrlen);

int listen(int sockfd,int backlog);

int accept(int sockfd,struct sockaddr *addr,socklen_t * addrlen);

int connect(int sockfd,struct sockaddr * serv_addr,socklen_t addrlen);

下面是在Windows下对应的程序：

客户端：

#include <stdio.h>
#include <stdlib.h>
#include <winsock2.h>
void error_handling(char * message);int main(int argc,char *argv[])
{WSADATA wsaData;SOCKET sock;SOCKADDR_IN serv_addr;char message[30];int str_len;if(argc!=3){printf("Usage : %s <IP> <port>\n",argv[0]);exit(1);}if(WSAStartup(MAKEWORD(2,2),&wsaData)!=0)error_handling("WSAStartup() error!");sock=socket(PF_INET,SOCK_STREAM,0);if(sock == INVALID_SOCKET)error_handling("socket() error");memset(&serv_addr,0,sizeof(serv_addr));serv_addr.sin_family=AF_INET;serv_addr.sin_addr.s_addr=inet_addr(argv[1]);serv_addr.sin_port=htons(atoi(argv[2]));if(connect(sock,(SOCKADDR *)&serv_addr,sizeof(serv_addr))==SOCKET_ERROR)error_handling("connect() error!");str_len=recv(sock,message,sizeof(message)-1,0);if(str_len==1)error_handling("read() error!");printf("Message from server : %s \n",message);closesocket(sock);WSACleanup();return 0;
}void error_handling(char *message)
{fputs(message,stderr);fputc('\n',stderr);exit(1);
}

服务器：

#include <stdio.h>
#include <stdlib.h>
#include <winsock2.h>void error_handling(char * message);int main(int argc,char *argv[])
{WSADATA wsaData;SOCKET hServSock,hClntSock;SOCKADDR_IN servAddr,clntAddr;int szClntAddr;char message[]="Hello World";if(argc!=2){printf("Usage : %s <IP> <port>\n",argv[0]);exit(1);		}if(WSAStartup(MAKEWORD(2,2),&wsaData)!=0)error_handling((char*)"WSAStartup() error!");hServSock=socket(PF_INET,SOCK_STREAM,0);if(hServSock == INVALID_SOCKET)error_handling((char*)"socket() error");memset(&servAddr,0,sizeof(servAddr));servAddr.sin_family=AF_INET;servAddr.sin_addr.s_addr=htonl(INADDR_ANY);servAddr.sin_port=htons(atoi(argv[1]));if(bind(hServSock,(SOCKADDR *)&servAddr,sizeof(servAddr))==SOCKET_ERROR)error_handling((char*)"bind() error");if(listen(hServSock,5)==SOCKET_ERROR)error_handling((char*)"listen() error");szClntAddr=sizeof(clntAddr);hClntSock=accept(hServSock,(SOCKADDR*)&clntAddr,&szClntAddr);if(hClntSock==INVALID_SOCKET)error_handling((char*)"accept() error");send(hClntSock,message,sizeof(message),0);closesocket(hClntSock);closesocket(hServSock);WSACleanup();return 0;
}void error_handling(char *message)
{fputs(message,stderr);fputc('\n',stderr);exit(1);
}

结果：