lib/proxy/dhcp/server/isc.rb
require 'time'
module Proxy::DHCP
class ISC < Server
def initialize options
super(options[:name])
@config = read_config(options[:config]).join("")
@leases = options[:leases]
end
def delRecord subnet, record
validate_subnet subnet
validate_record record
raise InvalidRecord, "#{record} is static - unable to delete" unless record.deleteable?
msg = "Removed DHCP reservation for #{record.name} => #{record}"
omcmd "connect"
omcmd "set hardware-address = #{record.mac}"
omcmd "open"
omcmd "remove"
omcmd("disconnect", msg)
subnet.delete record
end
def addRecord options = {}
record = super(options)
omcmd "connect"
omcmd "set name = \"#{record.name}\""
omcmd "set ip-address = #{record.ip}"
omcmd "set hardware-address = #{record.mac}"
omcmd "set hardware-type = 1" # This is ethernet
options = record.options
# TODO: Extract this block into a generic dhcp options helper
statements = []
statements << "filename = \\\"#{options[:filename]}\\\";" if options[:filename]
statements << bootServer(options[:nextServer]) if options[:nextServer]
statements << "option host-name = \\\"#{record.name}\\\";" if record.name
omcmd "set statements = \"#{statements.join(" ")}\"" unless statements.empty?
omcmd "create"
omcmd("disconnect", "Added DHCP reservation for #{record}")
record
end
def loadSubnetData subnet
super
conf = format((@config+@leases).split("\n"))
# scan for host statements
conf.scan(/host\s+(\S+\s*\{[^}]+\})/) do |host|
if match = host[0].match(/^(\S+)\s*\{([^\}]+)/)
hostname = match[1]
body = match[2]
opts = {:hostname => hostname}
body.split(";").each do |data|
opts.merge!(parse_record_options(data))
end
if opts[:deleted]
subnet.delete find_record_by_hostname(subnet, hostname)
next
end
end
begin
Proxy::DHCP::Reservation.new(opts.merge({:subnet => subnet})) if subnet.include? opts[:ip]
rescue Exception => e
logger.warn "skipped #{hostname} - #{e}"
end
end
conf.scan(/lease\s+(\S+\s*\{[^}]+\})/) do |lease|
if match = lease[0].match(/^(\S+)\s*\{([^\}]+)/)
next unless ip = match[1]
body = match[2]
opts = {}
body.split(";").each do |data|
opts.merge! parse_record_options(data)
end
next if opts[:state] == "free" or opts[:state] == "abandoned" or opts[:mac].nil?
Proxy::DHCP::Lease.new(opts.merge({:subnet => subnet, :ip => ip})) if subnet.include? ip
end
end
report "Enumerated hosts on #{subnet.network}"
end
private
def loadSubnets
super
@config.each_line do |line|
if line =~ /^\s*subnet\s+([\d\.]+)\s+netmask\s+([\d\.]+)/
Proxy::DHCP::Subnet.new(self, $1, $2)
end
end
"Enumerated the scopes on #{@name}"
end
#prepare text for parsing
def format text
text.delete_if {|line| line.strip.index("#") == 0}
return text.map{|l| l.strip.chomp}.join("")
end
def parse_record_options text
options = {}
case text
# standard record values
when /^hardware\s+ethernet\s+(\S+)/
options[:mac] = $1
when /^fixed-address\s+(\S+)/
options[:ip] = $1
when /^next-server\s+(\S+)/
options[:nextServer] = $1
when /^filename\s+(\S+)/
options[:filename] = $1
# Lease options
when /^binding\s+state\s+(\S+)/
options[:state] = $1
when /^starts\s+\d+\s+(.*)/
options[:starts] = parse_time($1)
when /^ends\s+\d+\s+(.*)/
options[:ends] = parse_time($1)
# used for failover - not implemented
when /^tstp\s+\d+\s+(.*)/
options[:tstp] = parse_time($1)
# OMAPI settings
when /^deleted/
options[:deleted] = true
when /^supersede server.next-server\s+=\s+(\S+)/
begin
ns = validate_ip hex2ip($1)
rescue
ns = $1.gsub("\"","")
end
options[:nextServer] = ns
when /^supersede server.filename\s+=\s+"(\S+)"/
options[:filename] = $1
when "dynamic"
options[:deleteable] = true
#TODO: check if adding a new reservation with omshell for a free lease still
#generates a conflict
end
return options
end
def omcmd cmd, msg=nil
if cmd == "connect"
@om = IO.popen("/bin/sh -c '/usr/bin/omshell 2>&1'", "r+")
@om.puts "key #{SETTINGS.dhcp_key_name} \"#{SETTINGS.dhcp_key_secret}\"" if SETTINGS.dhcp_key_name and SETTINGS.dhcp_key_secret
@om.puts "server #{name}"
@om.puts "connect"
@om.puts "new host"
elsif cmd == "disconnect"
@om.close_write
status = @om.readlines
@om.close
@om = nil # we cannot serialize an IO object, even if closed.
report msg, status
else
logger.debug filter_log "omshell: executed - #{cmd}"
@om.puts cmd
end
end
def report msg, response=""
if response.nil? or (!response.empty? and !response.grep(/can't|no more|not connected|Syntax error/).empty?)
logger.error "Omshell failed:\n" + (response.nil? ? "No response from DHCP server" : response.join(", "))
msg.sub! /Removed/, "remove"
msg.sub! /Added/, "add"
msg.sub! /Enumerated/, "enumerate"
msg = "Failed to #{msg}"
msg += ": Entry already exists" if response and response.grep(/object: already exists/).size > 0
msg += ": No response from DHCP server" if response.nil? or response.grep(/not connected/).size > 0
raise Proxy::DHCP::Collision, "Hardware address conflict." if response and response.grep(/object: key conflict/).size > 0
raise Proxy::DHCP::Error.new(msg)
else
logger.info msg
end
end
def ip2hex ip
ip.split(".").map{|i| "%02x" % i }.join(":")
end
def hex2ip hex
hex.split(":").map{|h| h.to_i(16).to_s}.join(".")
end
def find_record_by_hostname subnet, hostname
subnet.records.each do |v|
return v if v.options[:hostname] == hostname
end
end
# ISC stores timestamps in UTC, therefor forcing the time to load from GMT/UTC TZ
def parse_time str
Time.parse(str +" UTC")
rescue => e
logger.warn "Unable to parse time #{e}"
raise "Unable to parse time #{e}"
end
def bootServer server
begin
ns = ip2hex validate_ip(server)
rescue
begin
ns = ip2hex Resolv.new.getaddress(server)
rescue
logger.warn "Failed to resolve IP address for #{server}"
ns = "\\\"#{server}\\\""
end
end
"next-server = #{ns};"
end
def filter_log log
secret = SETTINGS.dhcp_key_secret
if secret.is_a?(String) and not secret.empty?
log.gsub!(SETTINGS.dhcp_key_secret,"[filtered]")
end
logger.debug log
end
def read_config file
logger.debug "Reading config file #{file}"
config = []
File.readlines(file).each do |line|
if /^include\s+"(.*)"\s*;/ =~ line.strip
conf = $1
unless File.exist?(conf)
raise "Unable to find the included DHCP configuration file: #{conf}"
end
config << read_config(conf)
else
config << line
end
end
return config
end
end
end