Thanx

-----Original Message-----
From: Dave Brown [mailto:community-noreply@qnx.com] 
Sent: Wednesday, September 24, 2008 6:30 AM
To: technology-networking
Subject: RE: broadcast using 255.255.255.255 actually sends
192.168.0.255

You should not need the manual route setting if using SO_BINDTODEVICE
with MSG_DONTROUTE. It is an alternative to using these options. Take a
look at the tech-note Sean posted earlier in the thread which describes
how broadcasting works. 

Dave

> -----Original Message-----
> From: Tim Gessner [mailto:community-noreply@qnx.com]
> Sent: Tuesday, September 23, 2008 6:34 PM
> To: technology-networking
> Subject: RE: broadcast using 255.255.255.255 actually sends
192.168.0.255
> 
> Sure, ifconfig below... Problem solved.  I added a route for
> 255.255.255.255 to 192.168.75.80 I also used SO_BINDTODEVICE and
> MSG_DONTROUTE and it seems to work.  If I understand correctly, QNX
> following some linux distros don't handle 255.255.255.255 correctly,
> instead they treat change it to the subnet broadcast of the first
> interface which supports broadcast.  To get around this, a route needs
> to be added and the stack told to not route and use the ip address as
> bound in the sendto.  Do I understand that correctly?
> 
> #ifconfig
> 
> lo0: flags=8009<UP, LOOPBACK, MULTICAST>
> 	capabilities=7<IP4CSUM,TCP4CSUM,UDP4CSUM>
> 	enabled=0<>
> 	inet 127.0.0.1 netmask 0xff000000
> 
> en0: flags=8843<UP, BROADCAST, RUNNING, SIMPLEX, MULTICAST> mtu 1500
> 	capabilities=7<IP4CSUM,TCP4CSUM,UDP4CSUM>
> 	enabled=0<>
> 	address: 00:d0:c9:a9:44:59
> 	inet 192.168.0.29 netmask 0xffffff00 broadcast 192.168.0.255
> 
> en1: flags=8843<UP, BROADCAST, RUNNING, SIMPLEX, MULTICAST> mtu 1500
> 	capabilities=7<IP4CSUM,TCP4CSUM,UDP4CSUM>
> 	enabled=0<>
> 	address: 00:d0:c9:a9:44:5a
> 	inet 192.168.75.80 netmask 0xffffff00 broadcast 192.168.75.255
> 
> 
> -----Original Message-----
> From: Robert Craig [mailto:community-noreply@qnx.com]
> Sent: Tuesday, September 23, 2008 3:11 PM
> To: technology-networking
> Subject: Re: broadcast using 255.255.255.255 actually sends
> 192.168.0.255
> 
> Can you post the ouput from ifconfig so that we can see your overall
> network configuration?
> 
>   R.
> 
> ----- Original Message -----
> From: Tim Gessner <community-noreply@qnx.com>
> To: technology-networking <post13909@community.qnx.com>
> Sent: Tue Sep 23 17:52:16 2008
> Subject: Re: broadcast using 255.255.255.255 actually sends
> 192.168.0.255
> 
> If I ping 192.168.0.255 (en0 broadcast) I get responses for all
devices
> on that subnet.
> 
> If I ping 192.168.75.255 (en1 broadcast) I don't get any responses
> except from en1 (there are more devices on that subnet).
> 
> If I ping 255.255.255.255 I get no route to host.
> 
> Please Help!
> 
> Thanx
> Tim
> 
> _______________________________________________
> Technology
> http://community.qnx.com/sf/go/post13909
> 
> 
> 
> _______________________________________________
> Technology
> http://community.qnx.com/sf/go/post13910
> 
> 
> _______________________________________________
> Technology
> http://community.qnx.com/sf/go/post13911


_______________________________________________
Technology
http://community.qnx.com/sf/go/post13932

I copied some code from dhcp and it works for QNX.

 #include <stdio.h>
        #include <unistd.h>
        #include <sys/types.h>
        #include <sys/socket.h>
        #include <netinet/in.h>
        #include <errno.h>
        #include <net/if.h>

        int main(void) {
        struct sockaddr_in name;
        int sock;
        int flag;
        struct ifreq ifr;
        char buf[80] = " broadcast layer2 + layer3 testing\n";
        short rport=3000, lport= 3000;
        struct sockaddr_in to;
        int result;

        memset (&name, 0, sizeof (name));
        name.sin_family = AF_INET;
        name.sin_port = htons(lport);
        name.sin_addr.s_addr = INADDR_ANY;

        if ((sock = socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP)) < 0)
                perror("can't create socket:");
        if ( setsockopt (sock, SOL_SOCKET, SO_BROADCAST,
                         (char *)&flag, sizeof flag) < 0)
                perror ("Can't set SO_BROADCAST option on socket: ");

        memset(&ifr, 0, sizeof(ifr));
        strncpy(ifr.ifr_name, "en0", sizeof("en0"));
        if ( setsockopt (sock, SOL_SOCKET, SO_BINDTODEVICE,
                        (char *)&ifr, sizeof ifr) < 0)
                perror ("setsockopt: SO_BINDTODEVICE: ");

        memset (&to, 0, sizeof (to));
        to.sin_family = AF_INET;
        to.sin_port = htons(rport);
        to.sin_addr.s_addr = INADDR_BROADCAST;

        while(1) {
        result = sendto (sock, buf, strlen(buf), 0,
                         (struct sockaddr *)&to, sizeof to);
        if (result < 0)
                printf("send to result:%d errno:%d\n", result, errno);
        sleep(2);
        }

        }