Re: [lwip-users] filter broadcast packet

[Piero 74]

I found up to know two important protocols which use broadcast:

ARP: has its own ethernet type... it is simple to find if broadcast packet is arp packet
DHCP: is based on udp: i think it is difficoult to filter in emac irq function

Do you know other protocol? how i can check if there is dhcp packet at ethernet frame level?

2008/1/25, Piero 74 <address@hidden>:

Hi all

I want to reduce cpu overhead in my board, running lwip.
My board will be placed as in big network as in small network.

I know that it will receive a lot of broadcast packets, and i want to filter them in the emac driver code, without call lwip stack.
So, my idea is:

1. configure emac HW for accepting all broadcast packet
2. in irq function, when new packet arrives, check if it's BROADCAST and if it has ARP value as ethernet type: ONLY in this case pass packet to lwip stack. In OTHER case discards packet.

Are there other packet type rather than ARP which are sent using broadcast mac address? (FF:FF:FF:FF:FF:FF)

Thanks for answers.

Bye, Piero