[lwip-users] Re: [lwip] lwip-cvs-20020108 errors

[leon . woestenberg]

Hello people,

> > Your function ip_addr_isbroadcast() works correct but it is ANDed with
> > ip_addr_maskcmp() - why? Only local broadcasts are recognized in that
way.
> > General Broadcasts (255.255.255.255) are dropped!
> > Without ip_addr_maskcmp() general broadcasts are recognized too.

> Just removing the ip_addr_maskcmp() would introduce problems since this
would
> mean that broadcasts to other networks would be let through. A packet to
> 192.168.255.255 would pass even if "our" network was 10.0.255.255, which
we
> don't want. Instead an additional check should be added:
> ip_addr_cmp(&(iphdr->dest), IP_ADDR_BROADCAST). This would explicitly
check
> for packets to 255.255.255.255.
>
Does someone know what the 255.255.255.255 broadcast address is expected to
address?

When sending to 255.255.255.255, does it mean sending out on all
interfaces?
In developing my own IP stack, I could not find a clear RFC reference on
this.

Regards, Leon.

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