linux下简单网络编程

编写网络程序一般分为客户程序和服务程序，主要有TCP和UPD两个协议，TCP服务程序的主要流程有socket()->bind()->listen()->accept()->对数据的操作，客户程序主要是socket()->connect()->对数据的操作，在编写程序时可通过函数的返回值判断是哪一步出了问题，问题便可解决。对于UPD流程没什么问题，主要步骤都差不多。

service：

#include<sys/wait.h>

#define SOCKETPORT 2222

#define SOCKETNUM 10

int main(int argc,char **argv)

{

struct sockaddr_in serv,clien;

int sockfd;

char buffer[100];

sockfd=socket(AF_INET,SOCK_STREAM,0);

serv.sin_family=AF_INET;

serv.sin_port=htons(SOCKETPORT);

serv.sin_addr.s_addr=htonl(INADDR_ANY);

bind(sockfd,(struct sockaddr *)&serv,sizeof(struct sockaddr_in));

listen(sockfd,10);

while(1)

{

int sin_size=sizeof(struct sockaddr_in);

int fd=accept(sockfd,(struct sockaddr *)&clien,&sin_size);

if(fd==-1)printf("dgdgd/n");

printf("recevied a connetion form %s/n",inet_ntoa(clien.sin_addr));

if(send(fd,"hello,you are connected !/n",26,0)==-1)

printf("error");

//recv(fd,buffer,sizeof(buffer),0);

//printf("%s/n",buffer);

}

return 0;

}

client：

#include<stdio.h>

#include<stdlib.h>

#include<errno.h>

#include<string.h>

#include<sys/types.h>

#include<netinet/in.h>

#include<sys/socket.h>

#include<sys/wait.h>

#define SOCKETPORT 2222

#define SOCKETNUM 10

int main(int argc,char **argv)

{

struct sockaddr_in serv;

int sockfd;

char buffer[100];

sockfd=socket(AF_INET,SOCK_STREAM,0);

serv.sin_family=AF_INET;

serv.sin_port=htons(SOCKETPORT);

serv.sin_addr.s_addr=inet_addr(argv[1]);

int clientfd=connect(sockfd,(struct sockaddr *)&serv,sizeof(struct sockaddr));

//send(sockfd,"hello,you are connected! /n",26,0);

recv(sockfd,buffer,100,0);

printf("%s/n",buffer);

return 0;

}