From: Thomas Lamprecht <t.lamprecht@proxmox.com>
To: Proxmox VE development discussion <pve-devel@lists.proxmox.com>,
"DERUMIER, Alexandre" <Alexandre.DERUMIER@groupe-cyllene.com>,
"aderumier@odiso.com" <aderumier@odiso.com>
Subject: Re: [pve-devel] [PATCH pve-cluster] sysctl: disable net.ipv4.igmp_link_local_mcast_reports
Date: Tue, 9 Nov 2021 17:15:17 +0100 [thread overview]
Message-ID: <46238588-9bd7-94e8-bf54-abe9d782f625@proxmox.com> (raw)
In-Reply-To: <d287fefb29cdf7bc1ecafb04582d25e06a9ec401.camel@groupe-cyllene.com>
On 09.11.21 16:52, DERUMIER, Alexandre wrote:
> This is really specific to local-link multicast, and it's should only
> be use for some specific routing protocol
>
> https://yhbt.net/lore/all/1439396033-6264-1-git-send-email-pdowney@brocade.com/T/
> https://www.omnisecu.com/tcpip/ipv4-link-local-multicast-addresses.php
>
> So, I'll not break multicast services inside the vm.
>
> Maybe if hypervisor use ospf routing protocol, but anyway, we don't
> have any infos about true vm ip/mac on fwbr bridges.
hmm, ack thx for the info, so the sysctl can be fine.
> actually corretly activate the fwbr bridge before plugging to vmbr,
>
> my $create_firewall_bridge_linux = sub {
> ...
> &$cond_create_bridge($fwbr);
> &$activate_interface($fwbr);
> copy_bridge_config($bridge, $fwbr);
> veth_create($vethfw, $vethfwpeer, $bridge);
>
> &$bridge_add_interface($fwbr, $vethfw);
> &$bridge_add_interface($bridge, $vethfwpeer, $tag, $trunks);
> &$bridge_add_interface($fwbr, $iface);
> };
>
> but it seem that igmp is sent some millisecond later
>
> A simple sleep like,
>
> &$cond_create_bridge($fwbr);
> &$activate_interface($fwbr);
> sleep(1);
> &$bridge_add_interface($fwbr, $vethfw);
>
> and the igmp report from fwbr is not going to vmbr.
> (but, maybe this is more ugly than a sysctl knob)
>
yeah such sleeps are ugly and still racy, we could poll for the fwbr to be up?
E.g., something like:
my $round = 0;
while (1) {
last if PVE::Tools::file_read_firstline("/sys/class/net/$fwbr/operstate") =~ "up";
die "timeout on waiting for $fwbr to become ready\n" if ++$round > 100;
usleep(10 * 1000); # 100 * 10ms = 1s
}
(did not test it)
>> Should it be an FW option?
>
> It could be.
>
> but it need to be persistant at firewall service stop, as when we
> shutdown the server, igmp report could be emit on vm/ct shutdown.
> and at boot, it should be enabled before the vm auto-start
>
> Personnaly, I think it should be disabled by default, with an knob to
> enable it.
> , as a majority of basic users don't known what it is. (And advanced
> users using routing protocol, should be aware of this option).
ah yea, with default on I meant that the sysctl would be default on (so the local
mcast reporting default off), sorry for the confusion.
We wouldn't need a actual config knob either as an admin that depends on this can
just configure a higher-priority sysctl.d file..
next prev parent reply other threads:[~2021-11-09 16:15 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-06 8:32 Alexandre Derumier
2021-11-05 13:20 ` Thomas Lamprecht
2021-11-09 15:52 ` DERUMIER, Alexandre
2021-11-09 16:15 ` Thomas Lamprecht [this message]
2021-11-11 16:18 ` [pve-devel] applied: " Thomas Lamprecht
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