问题描述
我正在使用 Visual Studio 在 Windows 中编写代码，并尝试让一个应用程序使用 UDP 套接字向其他应用程序广播消息。这必须通过 UDP 套接字完成。
它只适用于一个客户端，但当我添加另一个客户端时就不行了，并且所有客户端都在同一个端口上侦听。
TX（服务器）
/* Example from: http://matrixsust.blogspot.com/2011/10/udp-server-client-in-c.html */
/* Use legacy sockets */
#define _WINSOCK_DEPRECATED_NO_WARNINGS
/* Add a linker to ws2_32.lib,the Winsock2 library */
#pragma comment(lib,"ws2_32.lib")
#include <stdio.h>
#include <winsock2.h>
int main()
{
WSADATA wsaData;
int sock,sin_size;
struct sockaddr_in server_addr;
struct hostent* host;
char send_data[1024];
boolean keep_running = 1;
unsigned int cmd_no_block_arg = 1;
int SERVER_PORT;
/* Obtain a valid port */
printf("Enter a port number to connect to (i.e. 7171):\n");
scanf_s("%d",&SERVER_PORT);
if ((SERVER_PORT < 1) || (SERVER_PORT > 665534))
{
SERVER_PORT = 7171;
}
/* Initialize Winsock version 2.2 */
WSAStartup(MAKEWORD(2,2),&wsaData);
/* CLIENT SIDE */
host = (struct hostent*) gethostbyname((char*)"127.0.0.1");
if ((sock = socket(AF_INET,SOCK_DGRAM,IPPROTO_UDP)) == -1)
{
perror("socket");
exit(1);
}
/* SETUP */
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(SERVER_PORT);
server_addr.sin_addr = *((struct in_addr*)host->h_addr);
memset(server_addr.sin_zero,sizeof(server_addr.sin_zero));
sin_size = sizeof(struct sockaddr);
/* Bind the socket,then enable non-blocking semantics */
if ((ioctlsocket(sock,FIONBIO,&cmd_no_block_arg) == SOCKET_ERROR))
{
printf("Could not non-bind socket. Error Code %i\n",WSAGetLastError());
}
while (keep_running)
{
printf("Type Something (q or Q to quit):");
gets_s(send_data,sizeof(send_data));
if ((strcmp(send_data,"q") == 0) || strcmp(send_data,"Q") == 0)
{
keep_running = 0;
}
else
{
sendto(sock,send_data,strlen(send_data),(struct sockaddr*) & server_addr,sizeof(struct sockaddr));
}
} // While
}
RX（客户）
/* Example from: http://matrixsust.blogspot.com/2011/10/udp-server-client-in-c.html */
#define _WINSOCK_DEPRECATED_NO_WARNINGS
/* Add a linker to ws2_32.lib,"ws2_32.lib")
#include <stdio.h>
#include <winsock2.h>
#include <sys/types.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
int main()
{
WSADATA wsaData;
int sock;
int addr_len,bytes_read;
char recv_data[1024],send_data[1024];
struct sockaddr_in server_addr,client_addr;
int sharing_flag = 1; /* Allow sharing */
unsigned int non_block_flag = 1;
unsigned int SERVER_PORT = 7171;
/* Obtain a valid port to connect to */
printf("Enter a port number to connect to (i.e. 7171):\n");
scanf_s("%d",&SERVER_PORT);
if ((SERVER_PORT < 1) || (SERVER_PORT > 65535))
{
SERVER_PORT = 7171;
}
/* Initialize Winsock version 2.2 */
WSAStartup(MAKEWORD(2,&wsaData);
/* SERVER SIDE: bind(),recvfrom(),sendto() */
if ((sock = socket(AF_INET,IPPROTO_UDP)) == -1) {
perror("Socket");
exit(1);
}
server_addr.sin_family = AF_INET;
server_addr.sin_port = htons(SERVER_PORT);
server_addr.sin_addr.s_addr = INADDR_ANY;
memset(server_addr.sin_zero,sizeof(server_addr.sin_zero));
/* Eliminates "ERROR on binding: Address already in use" error */
if (setsockopt(sock,SOL_SOCKET,SO_REUSEADDR,(void*)&sharing_flag,sizeof(sharing_flag)) == SOCKET_ERROR)
{
printf("Error on socket opt: %i\n",WSAGetLastError());
}
if ((bind(sock,sizeof(struct sockaddr)) == SOCKET_ERROR) ||
(ioctlsocket(sock,&non_block_flag) == SOCKET_ERROR))
{
printf("Error on socket bind: %i\n",WSAGetLastError());
}
addr_len = sizeof(struct sockaddr);
printf("\nUDPServer Waiting for client on port %i\n",SERVER_PORT);
while (1)
{
bytes_read = recvfrom(sock,recv_data,1024,(struct sockaddr*) & client_addr,&addr_len);
if (bytes_read >= 0)
{
recv_data[bytes_read] = '\0';
printf("\n(%s,%d) said : ",inet_ntoa(client_addr.sin_addr),ntohs(client_addr.sin_port));
printf("%s\n",recv_data);
fflush(stdout);
} /* if we read in bytes */
} /* while */
return 0;
}
解决方法
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