Re: [Dnsmasq-discuss] dnsmasq coding style
On 26-09-2019 18:03, Kurt H Maier wrote: On Thu, Sep 26, 2019 at 03:10:00PM +0300, Ariel Miculas wrote: What about the issue regarding trailing whitespaces? There are empty lines which have random tabs/spaces, also there are spaces before newline characters. What is the rationale against removing trailing whitespaces? This stuff only matters if your tooling is broken. khm Which is my it matters for open source projects. There will be people with broken tooling that commit trailing whitespace. And whitespace fixes can definitely make certain git tasks (like merging, rebasing or just inspecting diffs) more difficult than they otherwise would be. So it isn't a weird idea to aim for consistent white-space usage. -- Maarten ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
Re: [Dnsmasq-discuss] [BUG] [PATCH] RA are sent too fast and slows down the machine
It's perfectly valid to have multiple distinct prefixes configured on an
interface, so just remembering one subnet isn't good enough in the
general case. Although it's certainly an improvement over a single address.
I think a complete fix would be to remember all (interface, prefix)
pairs that we're doing RAs on, and only (re)start fast RAs for the
interface if the subnet isn't already being served RA's. I imagine this
list already exists somewhere, since the RAs are being sent there. But
it's been a while since I looked through the code.
-- Maarten
On 11-09-2019 23:40, Simon Kelley wrote:
That's nasty.
I'm not sure how to properly solve this. I'm inclined to apply your
patch, on the grounds that it at least works better.
Simon.
On 02/09/2019 18:45, Petr Mensik wrote:
Yes, it seems originating system is auto configuring interface on behalf
own RA. I have modified the test to include ip monitor output. It
receives autoconfiguration few seconds after bridge interface comes up.
Don't know how much is involved fact network namespace is used on a
bridge, it should not matter. A bit suspicious is STALE router just
before autoconfiguration. I doubt it is related, but Avahi is trying
mdns on that interfaces. Of course, Network Manager is touching it also.
Since it is custom interface created in namespace, any other host cannot
send RA to it. So I am positive it autoconfigures itself, at least on my
Fedora 29. Has same results when only bridge is used and when loopback
is also used.
14:32:22.711> 2: simbrinet6 fc58:a22:180d:7800::1/64 scope global
...
14:32:25.289> fe80::6887:6dff:fe07:6f54 dev simbr lladdr
6a:87:6d:07:6f:54 router STALE
14:32:25.293> prefix fc58:a22:180d:7800::/64dev simbr onlink autoconf
valid 1800 preferred 1800
14:32:27.317> 2: simbrinet6
fc58:a22:180d:7800:6887:6dff:fe07:6f54/64 scope global dynamic mngtmpaddr
14:32:27.318> valid_lft 1798sec preferred_lft 1798sec
Cheers,
Petr
On 8/30/19 11:26 PM, Simon Kelley wrote:
This is useful information, but what I don't understand, is where the
flooding comes from. Sure, this confusion means that unsolicted ra will
run every time there's a "new address" event, even if the new address
isn't on the expected interface, but I can't see how it generates more
"new address events" and therefore a flood of packets.
Unless, the originating system receives _its_own_ RA and that generates
a "new address" event?
Simon.
On 28/08/2019 20:38, Petr Mensik wrote:
Hi,
I have found what is going on.
That RA seems to be switching between dynamically assigned address and
manually assigned address. It is just wrong to assume there is one
address on physical interface, especially in IPv6 world.
It seems my patch (attached), checking just subnet and not caring for
exact address inside, fixes advertisement floods. But I am not sure
whether it also does not stop announces for new dynamic addresses as it
should. It might help to use valid parameter to distinguish between
static address and dynamic. I am unsure if it is required for both or
just dynamic one?
I am sure it would send once for newly created interface. I think it
should be enough, right?
Some notes from debugging:
Breakpoint 1, construct_worker (scope=, flags=, preferred=, valid=1800,
vparam=0x7ffc9afc2b60, if_index=2, prefix=64, local=0xa6dda4) at
dhcp6.c:685
2: /x *local = {__in6_u = {__u6_addr8 = {0xfc, 0x58, 0xa, 0x22, 0x18,
0xd, 0x78, 0x0, 0x8, 0x21, 0xd1, 0xff, 0xfe, 0x74, 0xec,
0x2a}, __u6_addr16 = {0x58fc, 0x220a, 0xd18, 0x78, 0x2108, 0xffd1,
0x74fe, 0x2aec}, __u6_addr32 = {0x220a58fc, 0x780d18,
0xffd12108, 0x2aec74fe}}}
Breakpoint 1, construct_worker (scope=, flags=, preferred=, valid=-1,
vparam=0x7ffc9afc2b60, if_index=2, prefix=64, local=0xa6ddec) at
dhcp6.c:685
685 ra_start_unsolicited(param->now, template);
2: /x *local = {__in6_u = {__u6_addr8 = {0xfc, 0x58, 0xa, 0x22, 0x18,
0xd, 0x78, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1},
__u6_addr16 = {0x58fc, 0x220a, 0xd18, 0x78, 0x0, 0x0, 0x0, 0x100},
__u6_addr32 = {0x220a58fc, 0x780d18, 0x0, 0x100}}}
Cooperative ip link:
2: simbr: mtu 1500 qdisc noqueue state
UP group default qlen 1000
link/ether 0a:21:d1:74:ec:2a brd ff:ff:ff:ff:ff:ff
inet 172.30.16.1/24 scope global simbr
valid_lft forever preferred_lft forever
inet6 fc58:a22:180d:7800:821:d1ff:fe74:ec2a/64 scope global dynamic
mngtmpaddr
valid_lft 1699sec preferred_lft 1699sec
inet6 fc58:a22:180d:7800::1/64 scope global
valid_lft forever preferred_lft forever
inet6 fe80::821:d1ff:fe74:ec2a/64 scope link
valid_lft forever preferred_lft forever
Regards,
Petr
On 8/27/19 10:42 PM, Maarten de Vries wrote:
Hey,
I haven't dug very deep yet, but I can comment on the intent of the
particular commit: without it, dnsmasq didn't do any unsolicited RAs on
interfaces that are created after dnsmasq was
Re: [Dnsmasq-discuss] [BUG] RA are sent too fast and slows down the machine
Hey, I haven't dug very deep yet, but I can comment on the intent of the particular commit: without it, dnsmasq didn't do any unsolicited RAs on interfaces that are created after dnsmasq was started. It definitely should do unsolicited RAs on those interfaces too, although obviously not quite so many so often. I'm not sure why that happens. Note that the commit didn't introduce the fast RAs, it only enabled unsolicited RAs (including fast) for newly created interfaces too. I wonder why this happens in those test cases and at-least one Raspberry Pi, but not on my server. Is there any information you could provide to pinpoint when exactly this bug triggers and when not? For example: what happens if the virtual interface is created before dnsmasq starts? Does it also trigger on bridge interfaces (which is what I personally tested the commit with) for you? I will attempt to investigate too, but I'm somewhat swamped for time so I can't promise fast results. Kinds regards, Maarten On 27-08-2019 10:45, Iain Lane wrote: On Wed, Aug 21, 2019 at 08:59:07PM +0200, Petr Mensik wrote: Hi Simon and Maarten, we discovered when playing with NetworkManager-ci [1], that lastest release is somehow broken. Test running dnsmasq are quite slow on latest release. I have created repeatable started script that reproduces it. Then used git bisect to find when it was broken. It seems fast sending were intentional in commit 0a496f059c1e9 [2], but maybe way it affects the system were underestimated. It is significant for systems that hit such issue. I think it has to be fixed to slow it down to short time interval, not endless loop. Reported as Fedora bug [3]. Thanks for this Petr. Would you be able to share the script you've used, so that perhaps an upstream developer could recreate the bug? Mainly I wanted to chime in and say that (in addition to the other instance referenced), we found this in the NetworkManager testsuite in Ubuntu. I didn't come up with a nice reproducer at the time, but we did identify the same commit and we've reverted it in Ubuntu. I posted on the ML back then but we didn't get much traction and I didn't follow up very aggressively. http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2018q4/012709.html https://launchpadlibrarian.net/405377161/dnsmasq_2.80-1_2.80-1ubuntu1.diff.gz (the commit ID referenced in the changelog there seems or from somewhere else, it's the same patch) Cheers, ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
Re: [Dnsmasq-discuss] No unsolicited RAs on interface that doesn't exist at startup
Awesome. Thanks for the quick merge, and of course dnsmasq itself :) -- Maarten On 12-05-18 00:24, Simon Kelley wrote: Patch slightly rearranged and applied. Thanks, Simon. On 10/05/18 21:07, Maarten de Vries wrote: I noticed that dnsmasq often wasn't sending any unsolicited RAs for me. This turned out to happen when the interface (a bridge interface) wasn't created yet at the time dnsmasq started. When dnsmasq is started after the interface is created, it sends RAs as expected. I assume this also extends to other types of virtual interfaces that are created after dnsmasq starts. Digging into the source, it seems to be caused by a missing call to ra_start_unsolicited for non-template contexts in construct_worker from src/dhcp6.c. The attached patch adds that call, but only if the interface index or address changed to prevent doing fast RAs for no reason. I tested it on my own server and it appears to work as expected. When the interface is created and configured, dnsmasq does fast RAs for a while and then settles into slow RAs. ___ Dnsmasq-discuss mailing list Dnsmasq-discuss@lists.thekelleys.org.uk http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
[Dnsmasq-discuss] No unsolicited RAs on interface that doesn't exist at startup
I noticed that dnsmasq often wasn't sending any unsolicited RAs for me.
This turned out to happen when the interface (a bridge interface) wasn't
created yet at the time dnsmasq started. When dnsmasq is started after
the interface is created, it sends RAs as expected. I assume this also
extends to other types of virtual interfaces that are created after
dnsmasq starts.
Digging into the source, it seems to be caused by a missing call to
ra_start_unsolicited for non-template contexts in construct_worker from
src/dhcp6.c. The attached patch adds that call, but only if the
interface index or address changed to prevent doing fast RAs for no reason.
I tested it on my own server and it appears to work as expected. When
the interface is created and configured, dnsmasq does fast RAs for a
while and then settles into slow RAs.
Kind regards,
-- Maarten
>From a8c3132085e31faf7d5e6326783f4d8e0e087b01 Mon Sep 17 00:00:00 2001
From: Maarten de Vries <maar...@de-vri.es>
Date: Thu, 10 May 2018 20:49:16 +0200
Subject: [PATCH] Start unsolicited RAs for non-template contexts.
---
src/dhcp6.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/src/dhcp6.c b/src/dhcp6.c
index 0853664..9beb646 100644
--- a/src/dhcp6.c
+++ b/src/dhcp6.c
@@ -647,8 +647,11 @@ static int construct_worker(struct in6_addr *local, int prefix,
is_same_net6(local, >start6, template->prefix) &&
is_same_net6(local, >end6, template->prefix))
{
+ if (template->if_index == if_index && IN6_ARE_ADDR_EQUAL(>local6, local))
+ continue;
template->if_index = if_index;
template->local6 = *local;
+ ra_start_unsolicited(param->now, template);
}
}
--
2.17.0
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