Re: rtentry and rtrequest

Alan Garfield wrote:
Hi all!

One word.... HOW! :)

I've no clue what this FreeBSD ARP stuff is all about, there is little
or no documentation, there are 14 different sock_addr's which seem to
have a bazillion different fields, and I cannot output a simple debug
statement without getting 'error: dereferencing pointer to incomplete
type' errors!

The ARP code is pretty well documented in TCP/IP Illustrated Volume 2 and hasn't really significantly changed. Whilst I personally dislike how reentry happens in some of the paths, it works. In BSD, ARP lives in the routing table, which can be confusing to newcomers; such entries have the RTF_LLINFO flag set.

From the sounds of it, if you are having to fake MAC addresses, you would be better off just enabling static mode ARP on the interface, possibly also enabling IFF_SMART ('manages own routes') on your interface and explicitly purging and re-adding your ARP entries from within your driver rather than trying to hack the rtrequest code to munge things on the fly. arp_rtrequest() is driver-independent code and will get hooked up to your code anyway when the net/ framework notices that your driver is one of IFT_ETHER.

Regards,
BMS
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