[ECOS] Sending Raw Ethernet packets (ether_output, ether_output_frame, __enet_send ?)

Andrew Lunn andrew@lunn.ch
Thu Nov 20 18:44:00 GMT 2003

On Thu, Nov 20, 2003 at 10:52:46AM -0700, kevin_lemay@agilent.com wrote:
> Oops,

> You Said SERVER. I quick check of the DHCP request services from my
> linux box shows that it uses standard UDP using the assigned IP
> address for the destination.

> It would appear that you could use the standard UDP socket routines
> if you could manually add the entry into the routing table. This
> would be easier to do that using a non-standard ethernet
> interface. Usually stacks have routines to add routes.

I don't see why you need to add a route entry? You are probably
assigning addresses for the subnet the server is already on. If not,
the default route will probably do the job of getting the reply to the
DHCP proxy.

The problem is with the arp entry. Since the device requesting the
address does not have an IP address, it obviously cannot have an arp
entry. Hence you cannot send a packet to it. It will also not respond
to arp requests. 

What you may be able to do is add a static arp entry, send the packet,
and then remove the static arp entry. 


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