Linux下UDP收/发广播消息简单实现

发送广播消息

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

 int main(void)
 {
     char rgMessage[] = "I am sending message to you!";
     int iFd;
     int iSendbytes;
     int iOptval = ;
     struct sockaddr_in Addr;
     if ((iFd = socket(AF_INET, SOCK_DGRAM, )) == -)
     {
         printf("socket fail\n");
         return -;
     }

     if (setsockopt(iFd, SOL_SOCKET, SO_BROADCAST | SO_REUSEADDR, &iOptval, sizeof(int)) < )
     {
         printf("setsockopt failed!");
     }
     memset(&Addr, , sizeof(struct sockaddr_in));
     Addr.sin_family = AF_INET;
     Addr.sin_addr.s_addr = inet_addr("255.255.255.255");
     Addr.sin_port = htons();

     while ()
     {
         if ((iSendbytes = sendto(iFd, rgMessage, strlen(rgMessage), , (struct sockaddr*)&Addr, sizeof(struct sockaddr))) == -)
         {
             printf("sendto fail, errno=%d\n", errno);
             return -;
         }
         printf("rgMessage=%s, rgMessageLen=%d,iSendbytes=%d\n", rgMessage, strlen(rgMessage), iSendbytes);
         sleep();
     }
     close(iFd);

     return ;
 }

接收广播消息

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

 int main(void) {  

     int iAddrLength;
     char rgMessage[];
     int iOptval = ;
     int iFd;
     struct sockaddr_in Addr;  

     if ((iFd = socket(AF_INET, SOCK_DGRAM, )) == -)
     {
         printf("socket fail\n");
         return -;
     }   

     if (setsockopt(iFd, SOL_SOCKET, SO_REUSEADDR, &iOptval, sizeof(int)) < )
     {
         printf("setsockopt failed!\n");
     }
     memset(&Addr, , sizeof(struct sockaddr_in));
     Addr.sin_family = AF_INET;
     Addr.sin_addr.s_addr = INADDR_ANY;
     Addr.sin_port = htons();
     iAddrLength = sizeof(Addr);  

     if (bind(iFd, (struct sockaddr *)&Addr, sizeof(Addr)) == -)
     {
         printf("bind failed!\n");
     }        

     while ()
     {
         if (recvfrom(iFd, rgMessage, sizeof(rgMessage), , (struct sockaddr *)&Addr, &iAddrLength) == -)
         {
             printf("recv failed!\n");
         }
         printf("recv:%s\n", rgMessage);
     }  

     close(iFd);   

     return ;
 }