TCP客户端 – 服务器“错误地址”错误（在C中）
虽然它似乎正确实现， 但是当我使用环回地址 （127.0.0.1） 建立连接时 ， 它会继续返回ERROR 。
除了简单的TCP客户端/服务器连接外，我还添加了一个案例：
如果客户端尝试发送数据但发现连接已关闭 ，则它也会关闭。 我通过检查接收的数据是否等于0（recv）来执行它。
给定错误 ：
CLIENT: Welcome to the Client mode Please, enter the Server's IP Address and Port (eg. 192.128.192.0 1320) 127.0.0.1 2700 Connected to the server. Now you can send messages Please, enter a message. Enter "FINISH" if you want to finish the connection ECHO client: connection closed ->: Success (1 bytes)Closing the connection SERVER: Hello and welcome to the Server mode Please, enter the Server's Port (eg. 1320) 2700 Server socket successfully configured Server listening [Clients allowed: 5] server: accept error: Bad address 客户实施：
#include #include #include #include #include #include #include #include #include #include #include /** struct sockaddr{ uint8_t sa_len; // struct length sa_family_t sa_family; //protocol family: AF_XXX char sa_data[8]; //socket addr } */ //void notConnected(); int main(){ struct sockaddr_in serv_addr; //port + ip_addr int my_socket, tcp_port; char serv_host_addr[30]; char buffer[1024], inbuff[1024]; int io_buffer; printf("Welcome to the Client mode\n"); //CONFIGURING THE CONNECTION my_socket = socket(AF_INET, SOCK_STREAM, 0);//(2) if(my_socket "); exit(EXIT_FAILURE); } bzero(&serv_addr, sizeof(serv_addr));//(4) printf("Please, enter the Server's IP Address and Port (eg. 192.128.192.0 1320) \n"); scanf("%s %d", serv_host_addr, &tcp_port);//(1) serv_addr.sin_family = AF_INET ; serv_addr.sin_port = htons(tcp_port); if(inet_pton(AF_INET,serv_host_addr,&serv_addr.sin_addr) "); exit(EXIT_FAILURE); } if((connect(my_socket, (struct sockaddr *) &serv_addr, sizeof(serv_addr) )) "); exit(EXIT_FAILURE); } //ONCE CONNECTED, START THE SENDING/RECEIVING printf("Connected to the server. Now you can send messages\n"); bzero(&buffer, sizeof(buffer)); while(strcmp(buffer, "OK\n") != 0){ printf("Please, enter a message. Enter \"FINISH\" if you want to finish the connection\n");//(3) bzero(&buffer, sizeof(buffer)); fgets(buffer, sizeof(buffer), stdin); io_buffer = send(my_socket, buffer, strlen(buffer),0);//(6) if(io_buffer "); exit(EXIT_FAILURE); } printf("ECHO %s (%d bytes)", buffer, io_buffer); //RECEIVE AND CHECK IF CONNECTION HAS BEEN CLOSED io_buffer = recv(my_socket, buffer, sizeof(buffer),0); if(io_buffer "); exit(EXIT_FAILURE); } else if(io_buffer == 0){ //THIS IS SERVER IS CLOSED perror("client: connection closed ->"); break; } printf("ECHO %s (%d bytes)", buffer, io_buffer); } printf("Closing the connection \n"); for(int i=0; i < 5; i++){ printf(". "); usleep(500000); } close(my_socket); }
服务器实现：
#include #include #include #include #include #include #include #include #include #define LISTENQ 5 int main() { struct sockaddr_in cli_addr, serv_addr; char buffer[1024]; int serv_socket, cli_socket, clilen, io_buffer; int tcp_port; printf("Hello and welcome to the Server mode\n"); // ASKING FOR PORT NUMBER if((serv_socket = socket(AF_INET, SOCK_STREAM, 0)) < 0){ perror("server: can't open stream socket"); exit(EXIT_FAILURE); } printf("Please, enter the Server's Port (eg. 1320) \n"); scanf("%d", &tcp_port); // CONFIGURING THE CONNECTION serv_addr.sin_family = AF_INET; serv_addr.sin_port = htons(tcp_port); serv_addr.sin_addr.s_addr = htonl(INADDR_ANY); // ASSIGNING A NAME TO THE SOCKET if(bind(serv_socket,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0){ perror("server: can't assign a name to the socket"); exit(EXIT_FAILURE); } printf("Server socket successfully configured\n"); printf("Server listening [Clients allowed: %d]\n", LISTENQ); if(listen(serv_socket, LISTENQ) < 0) { perror("server: fail to listen network"); exit(EXIT_FAILURE); } // READ & WRITE STREAM while(1){ //returns a file descriptor for the client cli_socket = accept(serv_socket,(struct sockaddr *) &cli_addr,(socklen_t *) sizeof(cli_addr)); if(cli_socket < 0){ perror("server: accept error"); exit(EXIT_FAILURE); } printf("Server successfully connected to Client\n"); while(1) { if ((io_buffer=recv(cli_socket,buffer,sizeof(buffer),0))<0){ perror("ERROR: recv"); exit(EXIT_FAILURE); } printf("\"%s\" received from client", buffer); if(strcmp(buffer, "FINISH") == 0) { break; } if ((io_buffer=send(cli_socket,buffer,strlen(buffer),0))!=strlen(buffer)){ perror("ERROR: send"); exit(EXIT_FAILURE); } bzero(buffer, sizeof(buffer)); } strcpy(buffer, "OK"); if ((io_buffer=send(cli_socket, buffer, strlen(buffer), 0)) != strlen(buffer)){ perror("ERROR: send"); exit(EXIT_FAILURE); } printf("\"OK\" message sent to the Client.\n"); printf("Closing the connection \n"); for(int i=0; i < 5; i++) { printf(". "); usleep(500000); } close(cli_socket); } }
在您的原始问题中，您的接听电话如下所示：
cli_socket = accept(serv_socket,(struct sockaddr *) &cli_addr, (socklen_t *) sizeof(cli_addr));
这将“ (socklen_t *) sizeof(cli_addr) ”作为接受的第三个参数传递。 这应该是指向结构大小的指针。 您应该传入指向socklen_t的指针，该指针包含作为参数2传递的结构的大小。 您当前传入的大小被解释为一个地址，这会导致程序在引用时崩溃。 代码应如下所示：
socklen_t cli_addr_size = sizeof(cli_addr); cli_socket = accept(serv_socket,(struct sockaddr *) &cli_addr, &cli_addr_size);