Red Hat Bugzilla – Bug 287471
/proc/net/snmp6 and /proc/net/dev_snmp6/* do not contain Icmp6OutEchos
Last modified: 2007-11-27 11:30:03 EST
Description of problem:
/proc/net/snmp6 and /proc/net/dev_snmp6/* contain various statistics which
net-snmp uses to allow remote management of a network node. These statistics
include counter of incoming IPv6 echo request, incoming echo replies and
outgoing echo replies, but number of outgoing echo requests is missing.
Net-snmp cannot implement part of its functionality because of missing nr. of
sent IPv6 echo requests.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. cat /proc/net/snmp6 | grep Echo
2. cat /proc/net/dev_snmp6/eth0 | grep Echo
It just occured to me why we don't nominally count OutEchos: Its because the
kernel doesn't send them. User space applications send them using raw or udp
sockets in which the hdrincl bit is set for outgoing messages. The kernel just
sees these as raw data, and there is no code path through which we can acurately
count on all the outgoing echos to pass. I'm going to see if I can come up with
something, but this may have to be a CANTFIX issue.
my upstream development on this can be tracked here:
Jan, I've got a patch that could use some testing. kernels are build in brew under:
They should implement ICMPOUTECHOS
If you could test and confrim, I would appreciate it. Thanks!
It does not work for me (at least in my KVM virtualized environment) -
Icmp6OutEchos is still zero:
$ uname -a
Linux rhel5-x86_64 2.6.18-53.el5.bz287471 #1 SMP Thu Oct 11 11:16:08 EDT 2007
x86_64 x86_64 x86_64 GNU/Linux
$ ping6 -c 3 2001:0db8:0:f101::1
PING 2001:0db8:0:f101::1(2001:db8:0:f101::1) 56 data bytes
64 bytes from 2001:db8:0:f101::1: icmp_seq=0 ttl=64 time=2.58 ms
64 bytes from 2001:db8:0:f101::1: icmp_seq=1 ttl=64 time=0.348 ms
64 bytes from 2001:db8:0:f101::1: icmp_seq=2 ttl=64 time=0.608 ms
$ grep Echo /proc/net/snmp6
Is here any way how I can help you to localize the problem?
One of the patches in bug #253278 adds the necessary counters.
Created attachment 260331 [details]
ok, heres a new test patch. It seems to work reasonably well for me. Please
confirm and I'll send it upstream and for RHEL5 review. Thanks!
By comment #5 I had in my mind that you do not need to care about this bug
anymore and close it when bug #253278 is fixed, but I checked the patch in
comment #6 and it works. Thank you very much.
I noticed slightly strange results - if I ping link-local IPv6 address, I get
outgoing echo requests counted on eth0, but incoming echo requests on loopback:
eth0 inet6 addr: fe80::216:3eff:fe74:fd65/64 Scope:Link
$ ping -I eth0 fe80::216:3eff:fe74:fd65/64
64 bytes from fe80::216:3eff:fe74:fd65: icmp_seq=0 ttl=64 time=0.357 ms
64 bytes from fe80::216:3eff:fe74:fd65: icmp_seq=1 ttl=64 time=0.070 ms
$ grep Echo /proc/net/dev_snmp6/*
I would expect that all packets go through the same interface, eth0 in this
case. I do not necessarily mean it is a bug, the results are just a little
Looks like upstream already has support for outEchos from this commit:
Looks like our work here is done for RHEL6