sending packet like broadcast

[Altera_Forum]

Hello all, 

is possible to send packets in uClinux like broadcast ?  I include code: ----------------------------  void udp_init_all(void) { // proved nastaveni ciloveho adresata soketoveho spojeni host = gethostbyname("192.168.3.255"); // remote server if(host==NULL)  { printf("Address error."); return; }   // nastav struktury a cilovy port adresata remoteServAddr.sin_family = host->h_addrtype; memcpy((char *) &remoteServAddr.sin_addr.s_addr, host->h_addr_list[0], host->h_length); // remoteServAddr.sin_port = htons(serverPort);   // navaz sitove spojeni if ((socketDescriptor = socket(AF_INET, SOCK_DGRAM, 0)) < 0)  { printf("Not able to create socket connection. \n");  return; // exit(1);  }   serverAddress.sin_family = AF_INET;  serverAddress.sin_addr.s_addr = inet_addr(SRC_IP_ADR); //"192.168.3.238");   }  --------------------------  and sending code in main cycle: -------------------------- // nastav adresu portu a posli udp paket remoteServAddr.sin_port = htons(serverPort);  if (sendto(socketDescriptor, out_buf, len, 0,  (struct sockaddr *) &remoteServAddr, sizeof(remoteServAddr)) < 0) { printf("I am not able to send data to remote server.\n");  // close(socketDescriptor); return; // exit(1);  }  -----------------------------  and code report me: I am not able to send data to remote server.  How can i send packets via broadcast ? Where is error ?   Thank you for answer.  Jan Naceradsky, Czech Republic

[Altera_Forum]

Is sending IP packets as braoadcast not just using the broadcast address of the terwork you ar targeting (e.g. 192.168.2,255) ?  

 As routers don't forward broadcasts, I suppose not giving a network address will not work.  -Michael

[Altera_Forum]

Yes, i use broadcast address (in my case 192.168.3.255). 

I found, that ping -c 5 192.168.3.255  send data, but without answer - 5 packets transmitting, 0 received.   May be i should use another function, not sendto(.....), in c source code.   Jan

[Altera_Forum]

I don't think that ping is bound to support broadcast. 

A user protocol that does support broadcast is UDP. You need to write code for both ends.  -Michael

[Altera_Forum]

When i use: 

ping -c 5 192.168.3.255 the command tries to send 5 packets, every packets i can see in wireshark, but the uclinux doesnot get answer. You mean, that i must to write program for pc (except program for uClinux) ?   (yes, i use the udp protocol)   Jan

[Altera_Forum]

Yes, 

-Michael

[Altera_Forum]

Hi, 

   --- Quote Start ---   When i use: ping -c 5 192.168.3.255 the command tries to send 5 packets, every packets i can see in wireshark, but the uclinux doesnot get answer.   --- Quote End ---     I think that you hit the command 'ping -c 5 192.168.3.255' from your Nios uClinux system. If so, please consider who will reply the answer. Can your network reply to the 'ping broadcast' ? MS Windows OS ignores such broadcasts and Linux can ignore those by setting 'echo "1" > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts'.  Kazu