Some REFUSED answers to DNSSEC-originated queries would
bypass the DNSSEC code entirely, and be returned as answers
to the original query. In the process, they'd mess up datastructures
so that a retry of the original query would crash dnsmasq.
If no IPv4 address is present on given interface, the tool would not
send any request. It would not report any error at the same time. Report
error if request send failed.
Signed-off-by: Petr Mensik <pemensik@redhat.com>
Currently, dhcp_release will only send a 'fake' release
when the address given is in the same subnet as an IP
on the interface that was given.
This doesn't work in an environment where dnsmasq is
managing leases for remote subnets via a DHCP relay, as
running dhcp_release locally will just cause it to
silently exit without doing anything, leaving the lease
in the database.
Change it to use the default IP on the interface, as the
dnsmasq source code at src/dhcp.c does, if no matching subnet
IP is found, as a fall-back. This fixes an issue we are
seeing in certain Openstack deployments where we are using
dnsmasq to provision baremetal systems in a datacenter.
While using Dbus might have seemed like an obvious solution,
because of our extensive use of network namespaces (which
Dbus doesn't support), this seemed like a better solution
than creating system.d policy files for each dnsmasq we
might spawn and using --enable-dbus=$id in order to isolate
messages to specific dnsmasq instances.
Signed-off-by: Brian Haley <haleyb.dev@gmail.com>
In a reply proving that a DS doesn't exist, it doesn't matter if RRs
in the auth section _other_ than NSEC/NSEC3 are not signed. We can't
set the AD flag when returning the query, but it still proves
that the DS doesn't exist for internal use.
As one of the RRs which may not be signed is the SOA record, use the
TTL of the NSEC record to cache the negative result, not one
derived from the SOA.
Thanks to Tore Anderson for spotting and diagnosing the bug.
If the cache size is very large, the malloc() call will overflow
on 32 bit platforms and dnsmasq will crash. Limit to an order of
magnitude less.
Thanks to Lili Xu for spotting this.
- aligned the handling of UBus connections with the DBus code as it
makes it a bit easier to comprehend;
- added logging to the various UBus calls to aid debugging from an
enduser point of view, but be careful to not flood the logs;
- show the (lack of) support for UBus in the configuration string.
msg_controllen should be set using CMSG_SPACE() to account for padding.
RFC3542 provides more details:
While sending an application may or may not include padding at the end
of last ancillary data in msg_controllen and implementations must
accept both as valid.
At least OpenBSD rejects control messages if msg_controllen doesn't
account for padding, so use CMSG_SPACE() for maximal portability. This
is consistent with the example provided in the Linux cmsg(3) manpage.
Dear Simon,
the attached patch removes three redundant prototypes from dnsmasq.h. There is no functional change.
Best regards,
Dominik
From c0b2ccfd20c4eec9d09468fdfe9b4ca8a8f8591e Mon Sep 17 00:00:00 2001
From: DL6ER <dl6er@dl6er.de>
Date: Sun, 10 Mar 2019 19:34:07 +0100
Subject: [PATCH] Remove redundant prototypes from dnsmasq.h
Signed-off-by: DL6ER <dl6er@dl6er.de>
We detected a performance issue on a dnsmasq running many dhcp sessions
(more than 10 000). At the end of the day, the server was only releasing
old DHCP leases but was consuming a lot of CPU.
It looks like curent dhcp pruning:
1) it's pruning old sessions (iterate on all current leases). It's
important to note that it's only pruning session expired since more
than one second
2) it's looking for next lease to expire (iterate on all current leases
again)
3) it launchs an alarm to catch next expiration found in step 2). This
value can be zero for leases just expired (but not pruned).
So, for a second, dnsmasq could fall in a "prune loop" by doing:
* Not pruning anything, since difftime() is not > 0
* Run alarm again with zero as argument
On a server with very large number of leases and releasing often
sessions, that can waste a very big CPU time.
Signed-off-by: Florent Fourcot <florent.fourcot@wifirst.fr>
There's no reason to stop reading the existing lease file
when dnsmasq is started and an invalid entry is found, it
can just be ignored. This was fallout from an Openstack
bug where the file was being written incorrectly with []
around IPv6 addresses.
It is possible for a config entry to have one address family specified by a
dhcp-host directive and the other added from /etc/hosts. This is especially
common on OpenWrt because it uses odhcpd for DHCPv6 and IPv6 leases are
imported into dnsmasq via a hosts file.
To handle this case there need to be separate *_HOSTS flags for IPv4 and IPv6.
Otherwise when the hosts file is reloaded it will clear the CONFIG_ADDR(6) flag
which was set by the dhcp-host directive.
