UDP服务器，带有2个UDP客户端

在我的代码中，客户端只将数据发送到服务器 . 但是，我想client1说要发送到服务器然后服务器将它转发到client2 . 我已经尝试了所有我能想到但却无法理解的东西 .

Server

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

int main() 
{ 
    int sock; 
    int addr_len, bytes_read; 
    char recv_data[1024]; 
    struct sockaddr_in server_addr , client_addr; 


    if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) 
    { 
        perror("Socket"); 
        exit(1); 
    } 

    server_addr.sin_family = AF_INET; 
    server_addr.sin_port = htons(5000); 
    server_addr.sin_addr.s_addr = INADDR_ANY; 
    bzero(&(server_addr.sin_zero),8); 


    if (bind(sock,(struct sockaddr *)&server_addr, 
    sizeof(struct sockaddr)) == -1) 
    { 
        perror("Bind"); 
        exit(1); 
    } 

    addr_len = sizeof(struct sockaddr); 

    printf("\nUDPServer Waiting for client on port 5000"); 
    fflush(stdout); 

    while (1) 
    { 

        bytes_read = recvfrom(sock,recv_data,1024,0,(struct sockaddr *)&client_addr, &addr_len); 

        recv_data[bytes_read] = '\0'; 
        if(strlen(recv_data)>1)
        {
            printf("\n(%s , %d) said : ",inet_ntoa(client_addr.sin_addr),ntohs(client_addr.sin_port)); 
            printf("%s", recv_data); 
            fflush(stdout); 
        }

        bytes_read = sendto(sock,recv_data,1024,0,(struct sockaddr *)&client_addr, &addr_len); 
        recv_data[bytes_read] = '\0';

    } 
 return 0; 
}

Client

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

int main(int argc, char** argv) 
{ 
    int sock,i=0,bytes_read; 
    struct sockaddr_in server_addr; 
    struct hostent *host; 
    char send_data[1024],recv_data[1024];
    char nickname[20];
    if(argc != 2)  
    {  
        printf("Usage : %s <Server-IP>\n",argv[0]);  
        exit(0);  
    }  

    printf("Enter a nickname:");
    scanf("%s",&nickname);

    printf("WELCOME %s ..Please (Enter) to start chat or Quit(q): ",&nickname);
    host= (struct hostent *) gethostbyname((char *)argv[1]); 


    if ((sock = socket(AF_INET, SOCK_DGRAM, 0)) == -1) 
    { 
        perror("socket"); 
        exit(1); 
    } 

    server_addr.sin_family = AF_INET; 
    server_addr.sin_port = htons(5000); 
    server_addr.sin_addr = inet_addr(argv[1]); //IP ADDRESS 
    bzero(&(server_addr.sin_zero),8); 


    while (1) 
    { 
        if(i>1)
        {
            printf("%s:",&nickname); 
        }
        gets(send_data); 

        if ((strcmp(send_data , "q") == 0) || strcmp(send_data , "Q") == 0) 
            break; 
        else
        {
            sendto(sock, send_data, strlen(send_data), 0,(struct sockaddr *)&server_addr, sizeof(struct sockaddr)); 


        bytes_read = recvfrom(sock, send_data, strlen(send_data), 0,(struct sockaddr *)&server_addr, sizeof(struct sockaddr)); 
        recv_data[bytes_read] = '\0';
        }
    i++;
    } 
}