NetBSD Problem Report #36966

From Wolfgang.Stukenbrock@nagler-company.com  Mon Sep 10 14:13:56 2007
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Date: Mon, 10 Sep 2007 16:13:48 +0200 (CEST)
From: Wolfgang Stukenbrock <Wolfgang.Stukenbrock@nagler-company.com>
Reply-To: Wolfgang.Stukenbrock@nagler-company.com
To: gnats-bugs@NetBSD.org
Subject: routed failed to update default route
X-Send-Pr-Version: 3.95

>Number:         36966
>Category:       kern
>Synopsis:       routed failed to update default route
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Sep 10 14:15:00 +0000 2007
>Last-Modified:  Tue Sep 11 02:20:00 +0000 2007
>Originator:     Wolfgang Stukenbrock
>Release:        NetBSD 3.1
>Organization:
Dr. Nagler & Company GmbH

>Environment:


System: NetBSD test-s0 3.1 NetBSD 3.1 (test-s0) #0: Tue Apr 3 11:33:43 CEST 2007 root@test-s0:/usr/src/sys/arch/i386/compile/test-s0 i386
Architecture: i386
Machine: i386
>Description:
	If there are multiple Routes that offers a default route, routed
	may try to change the current default entry. It will do it by a call
	with RTM_CHANGE to the routing socket.
	Accedently this will fail with a message like "routed[312]: write(rt_sock) RTM_CHANGE 0.0.0.0         -->172.16.3.1      metric=3 flags=0x2: Too many references: can't splice"
	The problem is located in /usr/src/sys/net/rtsock.c aroud line 305,
	where a call to rn_search() is done. The netmask radix-tree needs a
	specialy prepared netmask-setup to work - e.g. <len>ffffff<mask> for
	IPv4 addresses in the sockaddr structure.
	This problem can be solved by calling rn-addmask(9 in the search mode
	that will do the search and add nothing.
	The problem should not only aply to the default route, because all
	kind of lookups may result here in an invalid mask - dependent on the
	set of other masks in the system ...
>How-To-Repeat:
	setup multiple routes and use routed to manage routing.
>Fix:
	The folloing patch to /usr/src/sys/net/rtsock.c will solve the problem.
	The call to rn_search() has been replaced by a call to rn_addmask().

*** rtsock.c.orig       Fri Sep  7 10:48:54 2007
--- rtsock.c    Mon Sep 10 16:01:43 2007
***************
*** 297,308 ****
                rt->rt_refcnt++;
                if (rtm->rtm_type != RTM_GET) {/* XXX: too grotty */
                        struct radix_node *rn;
-                       extern struct radix_node_head *mask_rnhead;

                        if (Bcmp(dst, rt_key(rt), dst->sa_len) != 0)
                                senderr(ESRCH);
!                       if (netmask && (rn = rn_search(netmask,
!                                           mask_rnhead->rnh_treetop)))
                                netmask = (struct sockaddr *)rn->rn_key;
                        for (rn = rt->rt_nodes; rn; rn = rn->rn_dupedkey)
                                if (netmask == (struct sockaddr *)rn->rn_mask)
--- 297,307 ----
                rt->rt_refcnt++;
                if (rtm->rtm_type != RTM_GET) {/* XXX: too grotty */
                        struct radix_node *rn;

                        if (Bcmp(dst, rt_key(rt), dst->sa_len) != 0)
                                senderr(ESRCH);
!                       if (netmask && (rn = rn_addmask(netmask, 1,
!                                                rnh->rnh_treetop->rn_off)))
                                netmask = (struct sockaddr *)rn->rn_key;
                        for (rn = rt->rt_nodes; rn; rn = rn->rn_dupedkey)
                                if (netmask == (struct sockaddr *)rn->rn_mask)

>Audit-Trail:
From: Yoshiaki Sudo <sudo@iij.ad.jp>
To: gnats-bugs@NetBSD.org, Wolfgang.Stukenbrock@nagler-company.com
Cc: kern-bug-people@netbsd.org, gnats-admin@netbsd.org,
	netbsd-bugs@netbsd.org
Subject: Re: kern/36966: routed failed to update default route
Date: Tue, 11 Sep 2007 11:15:05 +0900 (JST)

 From: Wolfgang Stukenbrock <Wolfgang.Stukenbrock@nagler-company.com>
 Subject: kern/36966: routed failed to update default route
 Date: Mon, 10 Sep 2007 14:15:01 +0000 (UTC)

 > >Number:         36966
 > >Category:       kern
 > >Synopsis:       routed failed to update default route

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>Unformatted:

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