# pvl-hosts
DNS/DHCP hosts management/integration for ISC bind9 and dhcpd.
## Hosts
The `pvl.hosts-*` tools read hosts files as input, which have an ini format, using section names as hostnames to configure attributes for that host:
[foo]
ip = 192.0.2.1
ethernet = 00:11:22:33:44:55
[bar]
ip = 192.0.2.2
ethernet = 01:23:45:67:89:ab
The domain name for a host is determined from the basename of the config file, so this example file would generate something like the following output for use in a `zone "example.com" { ... }` zonefile:
$ bin/pvl.hosts-forward etc/hosts/example.com
foo A 192.0.2.1
bar A 192.0.2.2
And correspondingly, the reverse zone for `2.0.192.in-addr.arpa`:
$ bin/pvl.hosts-reverse --zone-prefix=192.0.2.0/24 etc/hosts/example.com
1 PTR foo.example.com.
2 PTR bar.example.com.
And the associated DHCP hosts:
$ bin/pvl.hosts-dhcp etc/hosts/example.com
host foo {
option host-name foo;
hardware ethernet 00:11:22:33:44:55;
fixed-address 192.0.2.1;
}
host bar {
option host-name bar;
hardware ethernet 01:23:45:67:89:ab;
fixed-address 192.0.2.2;
}
### Include directories
Host configs can be included:
$ cat etc/hosts/test
include = test.d/
$ cat etc/hosts/test.d/foo
ip = 192.0.2.1
$ cat etc/hosts/test.d/bar
ip = 192.0.2.2
$ bin/pvl.hosts-forward etc/hosts/test
foo A 192.0.2.1
bar A 192.0.2.2
Including a directory of files is equivalent to substituiting each file as a named section at the level of the include = statement. Note that this means that included files are treated directly as host definitions, IOW, you should NOT include a section name in an included host file unless you want to declare an additional subdomain:
$ cat etc/hosts/wrong.test
include = wrong.d/
$ etc/hosts/wrong.d/host
[host]
ip = 192.0.2.6
Using the --root-zone option to generate the full FQDN for the host:
$ bin/pvl.hosts-forward --root-zone etc/hosts/wrong.test
host.host.wrong.test A 192.0.2.6
### Host aliases
Hosts can specify DNS aliases:
[foo]
ip = 127.0.0.1
alias = test1
[bar]
ip = 127.0.0.2
alias = test2
$ bin/pvl.hosts-forward --forward-zone alias.test etc/hosts/alias.test
foo A 127.0.0.1
test1 CNAME foo
bar A 127.0.0.2
test2 CNAME bar
### Generated hosts
The hosts file format supports something similar to bind9's $GENERATE directive for hosts:
[asdf{1-3}]
ip = 10.100.100.$
$ bin/pvl.hosts-dns --forward-zone=asdf etc/hosts/asdf
asdf1@asdf A 10.100.100.1
asdf2@asdf A 10.100.100.2
asdf3@asdf A 10.100.100.3
Note that the generate directives are interpreted and compiled directly by pvl.hosts.
Most of the $GENERATE options should be supported, with a little clever hackery:
[asdf{1-5/2}{0,2}]
ip = 10.100.100.$${10}
$ bin/pvl.hosts-dns --forward-zone=asdf2 etc/hosts/asdf2
asdf01@asdf2 A 10.100.100.11
asdf03@asdf2 A 10.100.100.13
asdf05@asdf2 A 10.100.100.15
This feature can be used for generating reverse delegations:
[foo-{240-247}]
forward =
reverse = $.240/29.0.0.10.in-addr.arpa
ip = 10.0.0.$
$ bin/pvl.hosts-dns --reverse-zone=10 etc/hosts/reverse
240.0.0 CNAME 240.240/29.0.0.10.in-addr.arpa.
241.0.0 CNAME 241.240/29.0.0.10.in-addr.arpa.
242.0.0 CNAME 242.240/29.0.0.10.in-addr.arpa.
243.0.0 CNAME 243.240/29.0.0.10.in-addr.arpa.
244.0.0 CNAME 244.240/29.0.0.10.in-addr.arpa.
245.0.0 CNAME 245.240/29.0.0.10.in-addr.arpa.
246.0.0 CNAME 246.240/29.0.0.10.in-addr.arpa.
247.0.0 CNAME 247.240/29.0.0.10.in-addr.arpa.
### DHCP Options
The hosts need not specify any fixed ip address, leaving IP address allocation to dhcpd:
[foo]
ethernet = 00:11:22:33:44:55
$ bin/pvl.hosts-dhcp etc/hosts/dhcp1
host foo {
option host-name foo;
hardware ethernet 00:11:22:33:44:55;
}
### DHCP Boot options
The hosts can specify DHCP boot server/file options:
[foo]
ethernet = 00:11:22:33:44:55
boot = boot.lan:debian/wheezy/pxelinux.0
$ bin/pvl.hosts-dhcp etc/hosts/boot.dhcp
host foo {
option host-name foo;
hardware ethernet 00:11:22:33:44:55;
next-server boot.lan;
filename debian/wheezy/pxelinux.0;
}
### DHCP hosts in multiple subnets/domains
A host with different interfaces in multiple domains must specify unique interface names:
[foo.dhcp]
[[asdf]]
ip = 10.1.0.1
ethernet.eth1 = 00:11:22:33:44:55
[bar.dhcp]
[[asdf]]
ip = 10.2.0.1
ethernet.eth2 = 55:44:33:22:11:00
$ bin/pvl.hosts-dhcp etc/hosts/dhcp2
host asdf-eth1 {
option host-name asdf;
hardware ethernet 00:11:22:33:44:55;
fixed-address 10.1.0.1;
}
host asdf-eth2 {
option host-name asdf;
hardware ethernet 55:44:33:22:11:00;
fixed-address 10.2.0.1;
}
# `update`
A script to drive the *pvl.hosts* tools for maintaing a set of zone/host files for a DNS/DHCP server.
## Source host files
Creating a tree of symlinks for managing split zonefile domains can be useful:
$ tree etc/zones/
etc/zones/
├── forward
│ └── test
│ ├── asdf.test -> ../../../hosts/asdf.test
│ └── test -> ../../../hosts/test
└── reverse
└── 192.0.2
├── asdf.test -> ../../../hosts/asdf.test
└── test -> ../../../hosts/test
Given a structure like above, the `pvl.hosts-forward` can generate a single forward zone containing all sub-domains:
$ bin/pvl.hosts-forward --hosts-include etc/hosts/ etc/zones/forward/test/
foo A 192.0.2.1
bar A 192.0.2.2
quux.asdf A 192.0.2.5
Note that the directory name is treated separately as a zone origin; the file names within the domain are still treated as a flat namespace independent of the directory name (which is different than *pvl.hosts* would behave for `include = etc/zones/forward/test/`).
The same trick also works for `pvl.hosts-reverse`:
$ bin/pvl.hosts-reverse --hosts-include etc/hosts/ etc/zones/reverse/192.0.2/
1 PTR foo.test.
2 PTR bar.test.
5 PTR quux.asdf.test.
## Source zone files
The zonefile header should be written out manually, using an `$INCLUDE` directive to reference the (generated) hosts zonefile:
$ cat etc/zones/test
$TTL 3600
@ SOA foo.test. hostmaster.test. (
0 ; serial
1d ; refresh
5m ; retry
10d ; expiry
300 ; negative
)
NS foo
NS bar
$INCLUDE "forward/test"
## Operation
Use the *update* script to generate a complete set of output zonefiles:
$ ./bin/update
Commit...
Using commit timestamp: 1425049508
Updating forward host zones...
var/zones/forward/test: Generating forward hosts zone: etc/zones/forward/test/
Updating reverse host zones...
var/zones/reverse/192.0.2: Generating reverse hosts zone: etc/zones/reverse/192.0.2/
Updating DHCP hosts...
Copying zone includes...
Updating zones...
var/serials/test: Update serial: 1425049508 <- 1425049508
var/zones/test: Generate zone: etc/zones/test
Updating DHCP confs...
Testing zones...
Reload zones...
Reload zones
rndc: server reload successful
Testing DHCP...
Reload DHCP...
## Output zone files
The generated zone files can then be loaded by bind:
$ cat var/zones/test
$TTL 3600
@ SOA foo.test. hostmaster.test. 1425049508 1d 5m 10d 300
NS foo
NS bar
$INCLUDE "./var/zones/forward/test"
$ cat var/zones/forward/test
foo A 192.0.2.1
bar A 192.0.2.2
quux.asdf A 192.0.2.5
# *pvl-dns*
Low-level zonefile utilities.
## `bin/pvl.dns-process`
Process a zonefile to modify:
* `SOA` record serial
* `$INCLUDE` paths
$ bin/pvl.dns-process --serial $(date +%s) --include-path var/zones etc/zones/test
$TTL 3600
@ SOA foo.test. hostmaster.test. 1425049088 1d 5m 10d 300
NS foo
NS bar
$INCLUDE "var/zones/forward/test"
## `bin/pvl.dns-zone`
Load a zonefile and output any ZoneRecords that it contains, including `$GENERATE`ed and `$INCLUDE`ed records:
$ bin/pvl.dns-zone --zone=test var/zones/test
@ 3600 SOA foo.test. hostmaster.test. 1425049248 1d 5m 10d 300
@ 3600 NS foo
@ 3600 NS bar
foo 3600 A 192.0.2.1
bar 3600 A 192.0.2.2
quux.asdf 3600 A 192.0.2.5
Optionally `--check-hosts` for dupliates `A`/`AAAA` records.
Use `--reverse-prefix=192.0.2` to generate a reverse-dns zone from `A`/`AAAA` records:
$ bin/pvl.dns-zone --zone=test var/zones/test --reverse-prefix=192.0.2
1 PTR foo.test.
2 PTR bar.test.
5 PTR quux.asdf.test.
# Experimental features
Features that are still under development
* DHCP host status tracking from syslog/dhcpd.leases into a database
* SNMP network topology discovery