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.

An oversight meant that non-existance checking was being done
anyway.

(Should probably alter the default for this.)

If we're talking to upstream servers from a fixed port, specified by query-port
we create the fds to do this once, before dropping root, so that ports <1024 can be used.

But we call check_servers() before reading /etc/resolv.conf, so if the only servers
are in resolv.conf, at that point there will be no servers, and the fds get garbage
collected away, only to be recreated (but without root) after we read /etc/resolv.conf

Make pre-allocated server fds immortal, to avoid this problem.

If query-port is set, we create sockets bound to the wildcard address and the query port for
IPv4 and IPv6, but the IPv6 one fails, because is covers IPv4 as well, and an IPv4 socket
already exists (it gets created first). Set V6ONLY to avoid this.

Install-common section was creating superfluous '-d' directory in build
location.

Split the directory creation into individual install commands to cope
with cross platform differences of interpreting subsequent '-d'
arguments.  e.g. GNU appears to be fine.  Apple creates the stray
directory.
Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>

These were not deleted except in the case that a dhcp-optsfile
option was coincidentally provided.

I got reported bug in Fedora [1], that cname is broken in new releases.
At first I though this was false report, but there is still new
regression in cname handling.

Before, it accepted alias with trailing dot. Not it would accept only
target, but not alias.

cname=alias.,target

is no longer valid. The issue is it will count size to skip after
canonicalize. If that ignores trailing dot, next name would be "". And
that is invalid and refused, dnsmasq refuses to start.

I also think that any whitespace like tab should be possible after
comma. So this fixes also 30858e3b.

The way of accessing the list of available hashes on nettle was
vulnerable to breaking if the version of libnettle in use was
different to the version dnsmasq was compiled against.
Change to a new system if libnettle >= 3.4 is in use.
Older versions if nettle are still OK, once 3.4 is reached,
the ABi problem is fixed. Thanks to Petr Menšík for clues on this.

This fixes breakage of  DHCPv6 relay.

Use strlen to determine the length of the filename returned by
inotify, as in->len refers to the length of the buffer containing
the name, not the length of the name itself.

http://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2018q1/011950.htmlSigned-off-by: Andy Hawkins <andy@gently.org.uk>

Patch further modified by simon@thekelleys.org to avoid
out-of-bounds array access with an empty string, call strlen once,
and reverse order of filename verifcation and resolv-file test.