kern/137164: [netinet] [patch] assert panic imo_match_source()

[Stef Walter]

The following reply was made to PR kern/137164; it has been noted by GNATS.

From: Stef Walter <stef at memberwebs.com>
To: bug-followup at FreeBSD.org, jhanna at pangolin-systems.com, 
 Bruce Simpson <bms at incunabulum.net>
Cc:  
Subject: Re: kern/137164: [netinet] [patch] assert panic imo_match_source()
Date: Tue, 06 Oct 2009 10:37:31 -0500

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 Thanks for working on getting all these multicast fixes in. Much
 appreciated!
 
 Just one more thing, previous to 7.x FreeBSD would return EADDRINUSE
 in the case of a double IP_ADD_MEMBERSHIP. Software like quagga uses
 this error code to detect this condition.
 
 As patched (and MFC'd in 7.x and 8.x) EINVAL is returned instead and
 this confuses such software.
 
 Currently the multicast code does not remove memberships from its
 internal structures when an interface goes down. It's hard for userland
 to reliably track the condition of a multicast membership that didn't go
 away due to an interface going down. So software like quagga uses
 EADDRINUSE to track the condition.
 
 Obviously, as you Bruce mentioned, an better solution needs to be found
 eventually WRT to 'dynamic' interfaces and the multicast code. But for
 now would the attached patch be acceptable? It would prevent regressions
 from FreeBSD 6.x.
 
 Thanks for considering,
 
 Stef
 
 
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  name="freebsd-mcast-eaddrinuse.patch"
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  filename="freebsd-mcast-eaddrinuse.patch"
 
 --- sys/netinet/in_mcast.c.orig	2009-09-30 16:43:35.000000000 +0000
 +++ sys/netinet/in_mcast.c	2009-09-30 17:04:59.000000000 +0000
 @@ -2010,5 +2010,5 @@
  			 * is atomic with allocation of a membership.
  			 */
 -			error = EINVAL;
 +			error = EADDRINUSE;
  			goto out_inp_locked;
  		}
 
 
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