Create PTRs from dnsmasq's -dhcp-script command. Very quick-n-dirty, Works on My Active Directory™ tested.

Create-PtrFromDnsmasq.ps1

$dnsServer = '10.10.10.10'         # Replace with a DNS server accepting insecure updates.
$dnsDomain = 'home.mydomain.com'   # Replace with your domain name.

$dhcpCmd = $args[0]
$dhcpMac = $args[1]
$dhcpIp = $args[2]

if ( $args.count -eq 4 ) {
        $dhcpHostname = $args[3] -replace '[^a-zA-Z0-9-]', '-'
} else {
        $dhcpHostname = $dhcpMac -replace ':','-'
}

$ptr = ($dhcpIp -replace '^(\d+)\.(\d+)\.(\d+).(\d+)$','$4.$3.$2.$1') + '.in-addr.arpa.'

$nsupdateCmd = @"
server $($dnsServer)
update delete $($ptr) PTR
$(if ($dhcpCmd -ne 'del') {"update add $($ptr) 300 PTR $($dhcpHostname).$($dnsDomain)."} )
send
quit

"@

$nsupdateCmd | nsupdate

dnsmasq sends output like:

cmd mac-address ip-address hostname

Where cmd can be add (lease added), old (lease update), or del (lease removed). Hostname is optional, if provided by the client. See the dnsmasq man page for more information on what gets passed as environmental variables.

Requires nsupdate, which is commonly installed by default on Linux distros.