Unified rc.firewall ipfw me/me6 issue

[Luigi Rizzo]

On Sun, Jan 17, 2010 at 05:42:58PM +0900, Hajimu UMEMOTO wrote:
> Hi,
> 
> >>>>> On Sun, 10 Jan 2010 19:52:32 +0100
> >>>>> Luigi Rizzo <rizzo at iet.unipi.it> said:
> 
> rizzo> We only need one 'me' option that matches v4 and v6, because the
> rizzo> other two can be implemented as 'ip4 me' and 'ip6 me' at no extra
> rizzo> cost (the code for 'me' only scans the list corresponding to the
> rizzo> actual address family of the packet).  I would actually vote for
> rizzo> removing the 'me6' microinstruction from the kernel, and implement
> rizzo> it in /sbin/ipfw by generating 'ip6 me'.
> 
> rizzo> Feel free to commit the change yourself.
> 
> Thank you.  I've committed 1st patch and 3rd patch.
> I think it is better removing the 'me6' microinstruction from the
> kernel, and implement it in /sbin/ipfw by generating 'ip6 me'.
> However, it seems to me that /sbin/ipfw is not designed to generate
> two microinstructions (ip6 me) per one 'me6' easily.

Indeed, it might be useful to insert, at the beginning of function
ipfw_add, a small preprocessing step that translates all instances
of 'me6' into 'ip6 me' and then proceed with the current parsing.
While doing that, one could even NULL-terminate the array av[] so
we don't need to carry both ac and av throught the code.

Something like

	new_av = safe_calloc(ac*2 + 1, sizeof(char *);
	for (src = dst = 0; src < ac; src++) {
		if (!strcmp(av[src], "me6")) {
			new_av[dst++] = "ip6";
			new_av[dst++] = "me";
		} else {	
			new_av[dst++] = av[src];
		}
	}
	new_av[dst++] = NULL;
	av = new_av;
	ac = dst;

should do the job. Replacing the tests for 'ac > 0' and ac>1
is straightforward though it touches a large number of lines
(most of the usage is in the 'NEED1' macro.

cheers
luigi
> Sincerely,
> 
> --
> Hajimu UMEMOTO @ Internet Mutual Aid Society Yokohama, Japan
> ume at mahoroba.org  ume@{,jp.}FreeBSD.org
> http://www.imasy.org/~ume/
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