Linux 系統 - Socket 通信實例

socket service

// connect、bind、close 注意理解 這裏的 TCP 三次握手
 #include <stdio.h>
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <string.h>
 #include <netinet/in.h>
 #include <stdlib.h>
 #include <errno.h>
 #include <unistd.h>
 #include <arpa/inet.h>

 #define MAXLINE 1024
 int main(int argc,char **argv)
 {
 int listenfd,connfd;
 struct sockaddr_in sockaddr;  // socket address
 char buff[MAXLINE];
 int n;

 memset(&sockaddr,0,sizeof(sockaddr)); // 清空內存

 sockaddr.sin_family = AF_INET;
 sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);
 sockaddr.sin_port = htons(10004); // 使用端口

 listenfd = socket(AF_INET,SOCK_STREAM,0);

 bind(listenfd,(struct sockaddr *) &sockaddr,sizeof(sockaddr));

 listen(listenfd,1024);


 printf("Please wait for the client information\n");

 for(;;)
 {
 if((connfd = accept(listenfd,(struct sockaddr*)NULL,NULL))==-1)
 {
 printf("accpet socket error: %s errno :%d\n",strerror(errno),errno);
 continue;
 }

 n = recv(connfd,buff,MAXLINE,0);
 buff[n] = '\0';
 printf("recv msg from client:%s",buff);
 close(connfd);
 }
 close(listenfd);
 }

socket Client

 #include <stdio.h>
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <stdlib.h>
 #include <netinet/in.h>
 #include <errno.h>
 #include <string.h>
 #include <arpa/inet.h>
 #include <unistd.h>
 #define MAXLINE 1024
 int main(int argc,char **argv)
 {
 char *servInetAddr = "127.0.0.1";
 int socketfd;
 struct sockaddr_in sockaddr;
 char recvline[MAXLINE], sendline[MAXLINE];
 int n;

 if(argc != 2)
 {
 printf("client <ipaddress> \n");
 exit(0);
 }

 socketfd = socket(AF_INET,SOCK_STREAM,0);
 memset(&sockaddr,0,sizeof(sockaddr));
 sockaddr.sin_family = AF_INET;
 sockaddr.sin_port = htons(10004);
 inet_pton(AF_INET,servInetAddr,&sockaddr.sin_addr)
 if((connect(socketfd,(struct sockaddr*)&sockaddr,sizeof(sockaddr))) < 0 )
 {
 printf("connect error %s errno: %d\n",strerror(errno),errno);
 exit(0);
 }

 printf("send message to server\n");

 fgets(sendline,1024,stdin);

 if((send(socketfd,sendline,strlen(sendline),0)) < 0)
 {
 printf("send mes error: %s errno : %d",strerror(errno),errno);
 exit(0);
 }

 close(socketfd);
 printf("exit\n");
 exit(0);
 }