Bug 22737 - syslog gets spammed with /kernel: arp_rtrequest: bad gateway value
Summary: syslog gets spammed with /kernel: arp_rtrequest: bad gateway value
Status: Closed FIXED
Alias: None
Product: Base System
Classification: Unclassified
Component: bin (show other bugs)
Version: 4.1.1-STABLE
Hardware: Any Any
: Normal Affects Only Me
Assignee: ru
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2000-11-10 13:20 UTC by langd
Modified: 2001-11-27 17:09 UTC (History)
0 users

See Also:


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Description langd 2000-11-10 13:20:01 UTC
The symptom is, that syslog gets filled with the following
error message:

/kernel: arp_rtrequest: bad gateway value

making the relevant information hard to detect.

It only occurs if the machine hosts multiple ips
on a single interface, and routed is running. 
The problem does not happen with "gated".

The error message is created in /usr/src/sys/netinet/if_ether.c,
only if a RTM_RESOLVE request is processed and the passed
rtentry contains a gateway (struct sockaddr), which is either
not an address of AF_LINK or, the length-field is smaller than
a empty dummy struct sockaddr (if I interpreted the source right).
Unfortunately I'm not too familiar with the kernel in general
and with programming routing stuff.

I did not try to set a breakpoint in the kernel debugger
and debug the kernel online, to get more hints, where the
wrong gateway strcut sockaddr is passed from.

I suspect routed has a problem with the alias ips (they have
a 0xffffffff netmask, and itself as gateway) and somehow
writes a wrong value to the routing socket?

gated does not seem to have this problem, so you could
run gated instead. It also does not occur on machines without
alias ips.

By tcpdumping the RIP packets, I detected a few wrong
configured gateways ;-), but the information itself is 
not malformed, or s.th. so it's not because of
bogus routes broadcasting crap RIP packets.

Fix: 

use gated
How-To-Repeat: 
ifconfig <if> inet <alias ip> netmask 0xffffffff alias
routed -q
tail -f /var/log/messages
Comment 1 iedowse freebsd_committer freebsd_triage 2001-11-18 00:23:59 UTC
State Changed
From-To: open->feedback


Does this problem still exist?
Comment 2 iedowse 2001-11-18 16:26:03 UTC
Adding this to the audit trail.

------- Forwarded Message

Date: Sun, 18 Nov 2001 16:30:17 +0100
From: Daniel Lang <dl@leo.org>
To: iedowse@FreeBSD.org
Cc: langd@leo.org, freebsd-bugs@FreeBSD.org
Subject: Re: bin/22737: syslog gets spammed with /kernel: arp_rtrequest: bad gateway value
Message-ID: <20011118163017.A55510@atrbg11.informatik.tu-muenchen.de>
References: <200111180024.fAI0OGd46920@freefall.freebsd.org>

Dear Ian,

iedowse@FreeBSD.org wrote on Sat, Nov 17, 2001 at 04:24:16PM -0800:
> Synopsis: syslog gets spammed with /kernel: arp_rtrequest: bad gateway value
[..]
> Does this problem still exist?
> 
> http://www.FreeBSD.org/cgi/query-pr.cgi?pr=22737

apparently yes, I do not use dynamic routing any more, but
I just checked by starting routed. The entry in the syslog
appeared almost immediately:

/var/log/messages:
[..]
Nov 18 16:19:19 atleo2 /kernel: arp_rtrequest: bad gateway value
[..]

uname -a:
FreeBSD atleo2.leo.org 4.4-STABLE FreeBSD 4.4-STABLE #3: Fri Oct 12 20:46:54 CEST 2001     root@atleo2.leo.org:/usr/obj/usr/src/sys/ATLEO2  i386

ifconfig xl0:

xl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        inet 131.159.72.4 netmask 0xfffffe00 broadcast 131.159.73.255
        inet6 fe80::2a0:24ff:fe45:e715%xl0 prefixlen 64 scopeid 0x1 
        inet 131.159.72.16 netmask 0xffffffff broadcast 131.159.72.16
        inet 131.159.72.17 netmask 0xffffffff broadcast 131.159.72.17
        inet 131.159.72.18 netmask 0xffffffff broadcast 131.159.72.18
        inet 131.159.72.10 netmask 0xffffffff broadcast 131.159.72.10
        inet 131.159.72.21 netmask 0xffffffff broadcast 131.159.72.21
        inet 131.159.72.25 netmask 0xffffffff broadcast 131.159.72.25
        inet 131.159.72.5 netmask 0xffffffff broadcast 131.159.72.5
        inet 131.159.72.11 netmask 0xffffffff broadcast 131.159.72.11
        inet 131.159.72.19 netmask 0xffffffff broadcast 131.159.72.19
        inet 131.159.72.1 netmask 0xffffffff broadcast 131.159.72.1
        inet 131.159.72.31 netmask 0xffffffff broadcast 131.159.72.31
        inet 131.159.72.32 netmask 0xffffffff broadcast 131.159.72.32
        inet 131.159.72.24 netmask 0xffffffff broadcast 131.159.72.24
        inet 131.159.72.27 netmask 0xffffffff broadcast 131.159.72.27
        ether 00:a0:24:45:e7:15 
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active

If you need more info, let me know.

Best regards,
 Daniel
- -- 
IRCnet: Mr-Spock     - Cool people don't move, they just hang around. -  
Daniel Lang * dl@leo.org * ++49 89 289 25735  * http://www.leo.org/~dl/

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------- End of Forwarded Message
Comment 3 iedowse freebsd_committer freebsd_triage 2001-11-18 20:29:18 UTC
State Changed
From-To: feedback->open


This is still a problem.
Comment 4 ru freebsd_committer freebsd_triage 2001-11-27 17:06:32 UTC
State Changed
From-To: open->closed

Superseded by PR kern/29170. 


Comment 5 ru freebsd_committer freebsd_triage 2001-11-27 17:06:32 UTC
Responsible Changed
From-To: freebsd-bugs->ru