Linux下socket通信和多线程

服务端socket流程：socket() –> bind() –> listen() –> accept() –> 读取、发送信息（recv，send等）

客户端socket流程：socket() –> connect() –> 发送、读取信息（send，recv等）

参考：Socket基本操作

本文包含基本实现，多线程版本

基本实现

服务端监听某个端口，客户端连接之后发送数据——>客户端断开连接后，服务端也关闭了

服务端：

 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <string.h>

 const int Port = ;

 int main(void){
     int sock_fd;
     struct sockaddr_in mysock;
     struct sockaddr_in client_addr;
     int new_fd;
     socklen_t sin_size
     char buf[];
     char sedbuf[] = "recv successfully.\n";

     //初始化socket
     sock_fd = socket(AF_INET,SOCK_STREAM,);

     //编辑地址信息
     memset(&mysock,,sizeof(mysock));
     mysock.sin_family = AF_INET;
     mysock.sin_port = htons(Port);
     mysock.sin_addr.s_addr = INADDR_ANY;

     //绑定地址，然后监听
     bind(sock_fd,(struct sockaddr *)&mysock,sizeof(struct sockaddr));
     if(listen(sock_fd,) < -){
         printf("listen error.\n");
     }

     sin_size = sizeof(struct sockaddr_in);

     printf("listening...\n");
     new_fd = accept(sock_fd, (struct sockaddr *)&client_addr, &sin_size);//accpet
     while(){
         int len = recv(new_fd,buf,sizeof(buf),);
         fputs(buf,stdout);
         send(new_fd, sedbuf, sizeof(sedbuf), );
         if(strcmp(buf,"exit\n") == ){
             break;
         }
         memset(buf,,sizeof(buf));
     }
     close(new_fd);
     close(sock_fd);
     return ;

客户端：

 #include<stdio.h>
 #include<unistd.h>
 #include<stdlib.h>
 #include<sys/types.h>
 #include<sys/socket.h>
 #include<netinet/in.h>
 #include<netdb.h>
 #include<string.h>
 #include<errno.h>

 const int Port = ;

 int main(void){
     int sock_fd;
     char buf[], sendbuf[], recvbuf[];
     struct sockaddr_in server_addr;
     sock_fd = socket(AF_INET, SOCK_STREAM, );//初始化socket
     if(sock_fd == -){
         printf("%s\n",strerror(errno));
         return ;
     }

     bzero(&server_addr, sizeof(server_addr));//编辑服务端地址信息
     server_addr.sin_family = AF_INET;
     server_addr.sin_port = htons(Port);
     server_addr.sin_addr.s_addr = htonl(INADDR_ANY);

     int tmp = connect(sock_fd, (struct sockaddr *)(&server_addr),
         sizeof(struct sockaddr));//连接服务端socket
     if(tmp == -){
         printf("%s\n",strerror(errno));
         return ;
     }

     while(){
         fgets(sendbuf, sizeof(sendbuf), stdin);
         send(sock_fd, sendbuf, strlen(sendbuf), );
         if(strcmp(sendbuf, "exit\n") == )
             break;
         recv(sock_fd, recvbuf, sizeof(recvbuf), );
         fputs(recvbuf, stdout);
         memset(sendbuf, , sizeof(sendbuf));
         memset(recvbuf, , sizeof(recvbuf));
     }
     close(sock_fd);
     return;
 }

多客户端与服务端通信（多线程）

只需在服务端修改，增加多线程，就可以同时接收多个客户端发送的信息了。

服务端：

 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <string.h>
 #include <pthread.h>
 #include <unistd.h>

 const int Port = ;
 pthread_mutex_t g_mutext;

 struct pthread_data{
     struct sockaddr_in client_addr;
     int sock_fd;
 };

 void *serveForClient(void * arg);

 int main(void){
     int sock_fd;
     struct sockaddr_in mysock;
     struct pthread_data pdata;
     pthread_t pt;
     socklen_t sin_size = sizeof(struct sockaddr_in);
     struct sockaddr_in client_addr;
     int new_fd;

     //初始化socket
     sock_fd = socket(AF_INET,SOCK_STREAM,);

     //编辑地址信息
     memset(&mysock, , sizeof(mysock));
     mysock.sin_family = AF_INET;
     mysock.sin_port = htons(Port);
     mysock.sin_addr.s_addr = INADDR_ANY;

     //绑定地址，然后监听
     bind(sock_fd,(struct sockaddr *)&mysock,sizeof(struct sockaddr));
     if(listen(sock_fd,) < -){
         printf("listen error.\n");
     }

     printf("listening...\n");
     while(){
         //accpet
         new_fd = accept(sock_fd, (struct sockaddr *)&client_addr, &sin_size);
         pdata.client_addr = client_addr;
         pdata.sock_fd = new_fd;
         pthread_create(&pt, NULL, serveForClient, (void *)&pdata);
     }
     close(new_fd);
     close(sock_fd);
     return ;
 }

 void *serveForClient(void *arg){
     struct pthread_data *pdata = (struct pthread_data*)arg;
     int new_fd = pdata->sock_fd;
     char recvbuf[];
     char sendbuf[] = "recv successfully.\n";
     while(){
         recv(new_fd, recvbuf, sizeof(recvbuf), );
         fputs(recvbuf,stdout);
         strcpy(sendbuf, recvbuf);
         if(strcmp(recvbuf,"exit\n") == ){
             send(new_fd, "connection close.\n", sizeof("connection close.\n"), );
             break;
         }
         send(new_fd, sendbuf, sizeof(sendbuf), );
         memset(recvbuf,,sizeof(recvbuf));
     }
     //close(new_fd);评论中指出多了一次close，所以这里不close了，留待main函数中统一close
     pthread_exit();
 }