简单的linux下socket编程,分别基于TCP和UDP协议实现的简单程序
linux下socket编程可以概括为以下几个函数的运用:
socket()
bind()
listen()
connect()
accept()
read()
write()
close()函数
基于TCP实现
流程
server代码
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <netinet/in.h>
int main(int argc, char *argv[])
{
//1.创建TCP套接字
int sock_fd = 0;
sock_fd = socket(AF_INET,SOCK_STREAM,0);
if(sock_fd < 0)
{
perror("socket");
close(sock_fd);
exit(-1);
}
//2.定义并填充本机地址结构体信息
struct sockaddr_in my_addr;
bzero(&my_addr,sizeof(my_addr));
my_addr.sin_family = AF_INET;
my_addr.sin_port = htons(8080);
my_addr.sin_addr.s_addr = htonl(INADDR_ANY);
//3.bind绑定本机地址
int err_log = bind(sock_fd,(struct sockaddr *)&my_addr,sizeof(my_addr));
if(err_log != 0)
{
perror("bind");
close(sock_fd);
exit(-1);
}
//4.listen监听,修改套接字的属性
err_log = listen(sock_fd,10);
if(err_log != 0)
{
perror("listen");
close(sock_fd);
exit(-1);
}
//5.调用accept从连接队列取出一条可用连接
int acc_fd = 0;
struct sockaddr_in client_addr;
bzero(&client_addr,sizeof(client_addr));
socklen_t client_len = sizeof(client_addr);
printf("Listenning at 8080\n");
acc_fd = accept(sock_fd,(struct sockaddr *)&client_addr,&client_len);
if(acc_fd < 0)
{
perror("accept");
return -1;
}
int num = 0;
pid_t pid = fork();
if(pid < 0)
{
perror("fork");
return -1;
}
else if(pid == 0)
{
//6.通信
while(1)
{
char buf_recv[1024] = "";
int num = recv(acc_fd,buf_recv,sizeof(buf_recv),0);
if(num > 0)
{
printf("\rcline::%s\n",buf_recv);
printf("cecv::");
fflush(stdout);
}
if(num == 0)
break;
}
}else
{
while(1)
{
// send();
char buf[512] = "";
printf("cecv::");
fgets(buf,sizeof(buf),stdin);
*(buf+strlen(buf)-1) = '\0';
send(acc_fd,buf,strlen(buf),0);
}
}
//7.close关闭连接套接字
//8.close关闭监听套接字
close(acc_fd);
close(sock_fd);
return 0;
}
client代码
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <netinet/in.h>
int main(int argc, char *argv[])
{
if(argc < 2)
{
return 0;
}
//创建TCP套接子、
int sockfd = 0;
sockfd = socket(AF_INET,SOCK_STREAM,0);
if(sockfd < 0)
{
perror("socket");
exit(-1);
}
//定义并填充服务器地址结构体
struct sockaddr_in ser_addr;
bzero(&ser_addr,sizeof(ser_addr));
ser_addr.sin_family = AF_INET;
ser_addr.sin_port = htons(atoi(argv[1]));
ser_addr.sin_addr.s_addr = htonl(INADDR_ANY);
// inet_pton(AF_INET,argv[2],&ser_addr.sin_addr);
//建立链接调用connect函数
int err_log = connect(sockfd,(struct sockaddr *)&ser_addr,sizeof(ser_addr));
if(err_log != 0)
{
perror("connect");
close(sockfd);
exit(-1);
}
//通信
//send
pid_t pid = fork();
if(pid < 0)
{
perror("fork");
return -1;
}
else if(pid == 0)
{
while(1)
{
char buf[512] = "";
printf("cline::");
fgets(buf,sizeof(buf),stdin);
*(buf+strlen(buf)-1) = '\0';
int len = send(sockfd,buf,strlen(buf),0);
if(len < 0)
{
perror("send");
}
}
}else
while(1)
{
//recv
char buf_recv[512]= "";
recv(sockfd,buf_recv,sizeof(buf_recv),0);
printf("\rcrecv::%s\n",buf_recv);
printf("cline::");
fflush(stdout);
}
//close关闭套接子
close(sockfd);
return 0;
}
基于UDP实现
流程
server代码
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
int main(int argc, char *argv[])
{
int server_sockfd;
int len;
struct sockaddr_in my_addr; //服务器网络地址结构体
struct sockaddr_in remote_addr; //客户端网络地址结构体
int sin_size;
char buf[BUFSIZ]; //数据传送的缓冲区
memset(&my_addr,0,sizeof(my_addr)); //数据初始化--清零
my_addr.sin_family=AF_INET; //设置为IP通信
my_addr.sin_addr.s_addr=INADDR_ANY;//服务器IP地址--允许连接到所有本地地址上
my_addr.sin_port=htons(8000); //服务器端口号
/*创建服务器端套接字--IPv4协议,面向无连接通信,UDP协议*/
if((server_sockfd=socket(PF_INET,SOCK_DGRAM,0))<0)
{
perror("socket error");
return 1;
}
/*将套接字绑定到服务器的网络地址上*/
if (bind(server_sockfd,(struct sockaddr *)&my_addr,sizeof(struct sockaddr))<0)
{
perror("bind error");
return 1;
}
sin_size=sizeof(struct sockaddr_in);
printf("waiting for a packet.../n");
/*接收客户端的数据并将其发送给客户端--recvfrom是无连接的*/
if((len=recvfrom(server_sockfd,buf,BUFSIZ,0,(struct sockaddr *)&remote_addr,&sin_size))<0)
{
perror("recvfrom error");
return 1;
}
printf("received packet from %s:/n",inet_ntoa(remote_addr.sin_addr));
buf[len]='/0';
printf("contents: %s/n",buf);
/*关闭套接字*/
close(server_sockfd);
return 0;
}
client代码
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
int main(int argc, char *argv[])
{
int client_sockfd;
int len;
struct sockaddr_in remote_addr; //服务器端网络地址结构体
int sin_size;
char buf[BUFSIZ]; //数据传送的缓冲区
memset(&remote_addr,0,sizeof(remote_addr)); //数据初始化--清零
remote_addr.sin_family=AF_INET; //设置为IP通信
remote_addr.sin_addr.s_addr=inet_addr("127.0.0.1");//服务器IP地址
remote_addr.sin_port=htons(8000); //服务器端口号
/*创建客户端套接字--IPv4协议,面向无连接通信,UDP协议*/
if((client_sockfd=socket(PF_INET,SOCK_DGRAM,0))<0)
{
perror("socket error");
return 1;
}
strcpy(buf,"This is a test message"); // 发送的内容
printf("sending: '%s'/n",buf);
sin_size=sizeof(struct sockaddr_in);
/*向服务器发送数据包*/
if((len=sendto(client_sockfd,buf,strlen(buf),0,(struct sockaddr *)&remote_addr,sizeof(struct sockaddr)))<0)
{
perror("recvfrom");
return 1;
}
/*关闭套接字*/
close(client_sockfd);
return 0;
}