Re: [PATCH] gre: strict physical device binding

[David Miller <davem@davemloft.net>]

From: David Miller <davem@davemloft.net>
Date: Mon, 19 Jan 2009 17:22:24 -0800 (PST)

> From: Timo Teras <timo.teras@iki.fi>
> Date: Mon, 19 Jan 2009 12:50:05 +0200
> 
> > Check the device on receive path and allow otherwise identical devices
> > as long as the physical device differs.
> > 
> > This is useful for NBMA tunnels, where you want to use different gre IP
> > for each public IP available via different physical devices.
> > 
> > Signed-off-by: Timo Teras <timo.teras@iki.fi>
> 
> Seems reasonable, applied.
> 
> Thanks Timo.

BTW, isn't it much more efficient to implement this priority scoring
using a simple integer instead of this big honking 4 entry array of
pointers on the stack (one entry of which isn't even _used_)?

Something like:

	int score = 4;

	...
	for_each_hash_chain() {
		if (!match)
			continue;
		if (exact_match)
			return this_entry;
		this_score = 0;
		if (condition1)
			this_score |= 2;
		if (condition2)
			this_score |= 1;
		if (this_score < score) {
			score = this_score;
			cand = this_entry;
		}
	}
	...
	return cand;