基于TCP的全双工网络编程实践

首先我们先了解一下什么是全双工通信？

全双工数据通信允许数据同时在两个方向上传输，因此，全双工通信相当于是两个单工通信方式的结合，它要求发送设备和接收设备都有独立的接收和发送能力。

TCP服务端代码：

#include <stdio.h>             
#include <stdlib.h>           
#include <string.h>
#include <arpa/inet.h>             
#include <netdb.h>              
#include <netinet/in.h>       
#include <stdint.h>                       
#include <sys/socket.h>     
#include <sys/types.h>     
#include <unistd.h>      #define PORT 10000  void error()
{perror("Socket Creation Failed");exit(EXIT_FAILURE);
}int main()
{uint32_t sockfd,conn; char recvbuff[1024],sendbuff[1024]; struct sockaddr_in server_addr,client_addr;  socklen_t ClientLen; if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0){error();  }bzero(&server_addr, sizeof(server_addr));server_addr.sin_family = AF_INET;server_addr.sin_port = htons(PORT);server_addr.sin_addr.s_addr = htonl(INADDR_ANY);printf("Server is running...\n");int on=1;if((setsockopt(sockfd,SOL_SOCKET,SO_REUSEADDR,&on,sizeof(on)))<0){perror("setsockopt failed");exit(EXIT_FAILURE);}if (bind(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0){error(); }listen(sockfd, 5);printf("Server is listening...\n");conn = accept(sockfd, (struct sockaddr *)NULL, NULL);printf("Server is connected...\n");pid_t pid;pid = fork();if (pid == 0)  //子进程负责接收数据{while (1){bzero(&recvbuff, sizeof(recvbuff));recv(conn, recvbuff, sizeof(recvbuff), 0);printf("\nCLIENT : %s\n", recvbuff);sleep(5);}}else  //父进程负责发送发送数据{while (1){bzero(&sendbuff, sizeof(sendbuff));printf("\nType message here: ");fgets(sendbuff, 1024, stdin);send(conn, sendbuff, strlen(sendbuff) + 1, 0);printf("\nMessage Sent!\n");sleep(5);}}close(sockfd);printf("Server is offline...\n");return 0;
}

TCP服务端运行状态：

TCP客户端代码：

#include <stdio.h>             
#include <stdlib.h>          
#include <string.h> 
#include <arpa/inet.h>             
#include <netdb.h>               
#include <netinet/in.h>          
#include <stdint.h>                   
#include <sys/socket.h>     
#include <sys/types.h>     
#include <unistd.h>   #define PORT 10000  void error()
{perror("Socket Creation Failed");exit(EXIT_FAILURE);
}int main()
{uint32_t sockfd; char sendbuff[1024],recvbuff[1024]; struct sockaddr_in server_addr; if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0){error();}bzero(&server_addr, sizeof(server_addr));server_addr.sin_family = AF_INET;server_addr.sin_port = htons(PORT);server_addr.sin_addr.s_addr = htonl(INADDR_ANY);printf("Client is running...\n");connect(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr));printf("Client is connected...\n");pid_t pid;pid = fork();if (pid == 0)  //子进程{while (1){bzero(&sendbuff, sizeof(sendbuff));printf("\nType message here: ");fgets(sendbuff, 1024, stdin);send(sockfd, sendbuff, strlen(sendbuff) + 1, 0);printf("\nMessage sent!\n");sleep(5);}}else  //父进程{while (1){bzero(&recvbuff, sizeof(recvbuff));recv(sockfd, recvbuff, sizeof(recvbuff), 0);printf("\nSERVER: %s\n", recvbuff);sleep(5);}}close(sockfd);printf("Client is offline...\n");return 0;
}

TCP客户端运行状态：