[OpenWrt-Devel] [PATCH] [package] dnsmasq: use host-record instead of address
Julián Landerreche
maniqui at gmail.com
Sun Oct 11 17:37:56 EDT 2015
Hi Nathan,
thanks for sharing your patch. I'm the author of patch #3828, but I haven't
been able to access it at:
http://patchwork.openwrt.org/patch/3828/
and I don't have a local copy of it.
So I relied on your patch and it seems to work flawlessly.
Also, you said:
The patch (#3828) works well for a single hostname; however, if multiple
> names are specified, dhcp_host_add generates an invalid "dhcp-host" option.
I'm not sure what you mean, but I recall my original patch worked for more
than one name (ie. more than one host on my LAN network: computerA.lan,
computerB.lan, etc.), and it generated the same output that your patch
generates. That is:
address=/computerA/computerA.lan/10.0.0.2
address=/computerB/computerB.lan/10.0.0.3
Thanks again.
On Sun, Sep 8, 2013 at 9:21 PM, Nathan Hintz <nlhintz at hotmail.com> wrote:
> On Wed, 28 Aug 2013 15:05:35 -0600
> "Philip A. Prindeville" <philipp_subx at redfish-solutions.com> wrote:
>
> > I should have sent this AFTER trying out patch 3828.
> >
> > Julian's patch is even simpler than my suggestion.
> >
> > On 08/28/2013 02:42 PM, Philip A. Prindeville wrote:
> > > Sorry if it's a little after-the-fact, but I've been wondering
> > > about the need to have a separate "config domain" section at all.
> > >
> > > Why not just have something like:
> > >
> > > config host
> > > ...
> > > option wants-dns-rr on
> > >
> > > Yes, "config domain" is still useful for external sites or for
> > > resources with static addresses that aren't served by dnsmasq, buy
> > > why not reduce the amount of configuration for a host to have a
> > > A/PTR pair to a single line?
> > >
> > > For that matter, in the "config dnsmasq" section, why not have an
> > > option like "option publish-dns-rr on" and enable it globally for
> > > all host blocks?
> > >
> > > Am I missing something?
> > >
> > > -Philip
> > >
> > >
> > > On 06/04/2013 10:44 PM, Adam Gensler wrote:
> > >> Hi all,
> > >>
> > >> TL;DR - using "--address" for individual host A records is broken,
> > >> use "--host-record" instead.
> > >>
> > >> The following patch changes dnsmasq.init to build individual host
> > >> records using "--host-record" instead of "--address". Using
> > >> "--address" in this context is incorrect. For example, the current
> > >> init script will create the following two entries
> > >> in /var/etc/dnsmasq.conf:
> > >>
> > >> address=/OpenWrt.lan/192.168.1.1
> > >> ptr-record=1.1.168.192.in-addr.arpa,OpenWrt.lan
> > >>
> > >> At first glance this has the desired effect, "OpenWrt.lan"
> > >> resolves to 192.168.1.1. However, what it really says is "for
> > >> anything that ends with "OpenWrt.lan," that I don't have a record
> > >> for, return 192.168.1.1". For example:
> > >>
> > >> fakeaddress.OpenWrt.lan would return 192.168.1.1.
> > >> adsfasdfsdfsd.OpenWrt.lan would return 192.168.1.1.
> > >>
> > >> That's wrong and it causes problems when using a real domain name,
> > >> such as domain.com. Often it's desirable to have "domain.com"
> > >> resolve to an address so users can hit the http service at
> > >> http://domain.com. By using the existing "config domain" option,
> > >> you would configure this as follows:
> > >>
> > >> config domain
> > >> option name 'domain.com'
> > >> option ip '192.168.1.100'
> > >>
> > >> This would create these config items:
> > >>
> > >> address=/domain.com/192.168.1.100
> > >> ptr-record=100.1.168.192.in-addr.arpa,domain.com
> > >>
> > >> Now, as a result, anything that doesn't have its own, preexisting
> > >> record, will also resolve to 192.168.1.100. That's no good because
> > >> things like Windows do proxy requests by default for
> > >> wpad.domain.com and instead of getting back an NXDOMAIN, it gets
> > >> 192.168.1.100 and goes hunting for a pac file that doesn't exist.
> > >>
> > >> The solution for this is to use "--host-record". This is actually
> > >> a lot easier to configure because dnsmasq will create the PTR
> > >> records automatically, so there's no need to manual calculate it
> > >> like is done today. This means that IPv6 addresses can be
> > >> supported as well. The attached patch makes this adjustment and
> > >> accomplishes the following:
> > >>
> > >> 1. By default, the router's hostname is now added to the
> > >> configuration using "--host-record" instead of "--address". If
> > >> there's a domain configured, the default host-record entry looks
> > >> like this:
> > >>
> > >> host-record=OpenWrt.lan,OpenWrt,192.168.1.1
> > >>
> > >> With this, now both "OpenWrt.lan" and "OpenWrt" will both resolve
> > >> to 192.168.1.1. In the reverse, 192.168.1.1 will resolve to only
> > >> "OpenWrt.lan".
> > >>
> > >> 2. It introduces a new configuration structure to define
> > >> additional host records. For example:
> > >>
> > >> config hostrecord
> > >> list name 'mail.domain.com'
> > >> list name 'www.domain.com'
> > >> list name 'domain.com'
> > >> list ip '192.168.1.100'
> > >>
> > >> It uses lists here because dnsmasq can accept multiple hostnames
> > >> and IP addresses in a single host-record. This generates the
> > >> following config:
> > >>
> > >> host-record=mail.domain.com,www.domain.com,domain.com,192.168.1.100
> > >>
> > >> All of those hostnames will resolve to 192.168.1.100 in the
> > >> forward direction. 192.168.1.100 will resolve to "mail.domain.com"
> > >> in the reverse.
> > >>
> > >> 3. It restructures "dhcp_domain_add()" to remove the manual PTR
> > >> record calculation and configuration. This only supported IPv4 and
> > >> isn't the proper use of the "--address" option. Now it will build
> > >> a proper "--address" config that can support multiple domain names
> > >> to a single IP address as per the dnsmasq MAN page.
> > >>
> > >> Note, the domain name is no longer automatically appended to the
> > >> end of either "config hostrecord" or "config domain" entries as
> > >> was previously the case. To define a specific fqdn, one needs to
> > >> manually configure it as such. This makes the configuration more
> > >> consistent; only what's configured is what is generated for
> > >> dnsmasq.
> > >>
> > >> Sorry for the long email. I hope it all made sense. If not, please
> > >> let me know.
> > >>
> > >> Thanks,
> > >> Adam
> > >>
> > >>
> > >> Signed-off-by: Adam Gensler <openwrt at gnslr.us>
> > >> ---
> > >> [snip]
> > > _______________________________________________
> > > openwrt-devel mailing list
> > > openwrt-devel at lists.openwrt.org
> > > https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
> > _______________________________________________
> > openwrt-devel mailing list
> > openwrt-devel at lists.openwrt.org
> > https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
> >
>
> Hi:
>
> The patch (#3828) works well for a single hostname; however, if multiple
> names are specified, dhcp_host_add generates an invalid "dhcp-host" option.
>
> dhcp_host_add could be modified to only use the first name encountered
> (see below).
>
> Nathan
>
> Index: package/network/services/dnsmasq/files/dnsmasq.init
> ===================================================================
> --- package/network/services/dnsmasq/files/dnsmasq.init (revision 37919)
> +++ package/network/services/dnsmasq/files/dnsmasq.init (working copy)
> @@ -254,6 +254,7 @@
> [ -n "$networkid" ] && dhcp_option_add "$cfg" "$networkid" "$force"
>
> config_get name "$cfg" name
> + name="${name/ */}"
> config_get ip "$cfg" ip
> [ -n "$ip" -o -n "$name" ] || return 0
>
> @@ -408,6 +409,24 @@
> xappend "--address=/$record/$ip"
> }
>
> +dhcp_address_add() {
> + local cfg="$1"
> + local ip name names record
> +
> + config_get names "$cfg" name "$2"
> + [ -n "$names" ] || return 0
> +
> + config_get ip "$cfg" ip "$3"
> + [ -n "$ip" ] || return 0
> +
> + for name in $names; do
> + fqdn="$name${DOMAIN:+.$DOMAIN}"
> + record="${record:+$record/}$name/$fqdn"
> + done
> +
> + xappend "--address=/$record/$ip"
> +}
> +
> dhcp_srv_add() {
> local cfg="$1"
>
> @@ -512,6 +531,7 @@
> config_foreach dhcp_subscrid_add subscrid
> config_foreach dhcp_domain_add domain
> config_foreach dhcp_hostrecord_add hostrecord
> + config_foreach dhcp_address_add host
>
> # add own hostname
> [ $ADD_LOCAL_HOSTNAME -eq 1 ] && [ -n "$lanaddr" ] && {
> --
> Nathan
> _______________________________________________
> openwrt-devel mailing list
> openwrt-devel at lists.openwrt.org
> https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
>
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