diff options
Diffstat (limited to 'src/conf_mode/dhcp_server.py')
| -rwxr-xr-x | src/conf_mode/dhcp_server.py | 142 |
1 files changed, 84 insertions, 58 deletions
diff --git a/src/conf_mode/dhcp_server.py b/src/conf_mode/dhcp_server.py index 3e1381cd0..f19bcb250 100755 --- a/src/conf_mode/dhcp_server.py +++ b/src/conf_mode/dhcp_server.py @@ -1,6 +1,6 @@ #!/usr/bin/env python3 # -# Copyright (C) 2018 VyOS maintainers and contributors +# Copyright (C) 2018-2019 VyOS maintainers and contributors # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License version 2 or later as @@ -13,18 +13,16 @@ # # You should have received a copy of the GNU General Public License # along with this program. If not, see <http://www.gnu.org/licenses/>. -# -# import sys import os -import ipaddress import jinja2 import socket import struct import vyos.validate +from ipaddress import ip_address, ip_network from vyos.config import Config from vyos import ConfigError @@ -253,6 +251,68 @@ default_config_data = { 'shared_network': [], } +def dhcp_slice_range(exclude_list, range_list): + """ + This function is intended to slice a DHCP range. What does it mean? + + Lets assume we have a DHCP range from '192.0.2.1' to '192.0.2.100' + but want to exclude address '192.0.2.74' and '192.0.2.75'. We will + pass an input 'range_list' in the format: + [{'start' : '192.0.2.1', 'stop' : '192.0.2.100' }] + and we will receive an output list of: + [{'start' : '192.0.2.1' , 'stop' : '192.0.2.73' }, + {'start' : '192.0.2.76', 'stop' : '192.0.2.100' }] + The resulting list can then be used in turn to build the proper dhcpd + configuration file. + """ + output = [] + # exclude list must be sorted for this to work + exclude_list = sorted(exclude_list) + for ra in range_list: + range_start = ra['start'] + range_stop = ra['stop'] + range_last_exclude = '' + + for e in exclude_list: + if (ip_address(e) >= ip_address(range_start)) and \ + (ip_address(e) <= ip_address(range_stop)): + range_last_exclude = e + + for e in exclude_list: + if (ip_address(e) >= ip_address(range_start)) and \ + (ip_address(e) <= ip_address(range_stop)): + + # Build new IP address range ending one IP address before exclude address + r = { + 'start' : range_start, + 'stop' : str(ip_address(e) -1) + } + # On the next run our IP address range will start one address after the exclude address + range_start = str(ip_address(e) + 1) + + # on subsequent exclude addresses we can not + # append them to our output + if not (ip_address(r['start']) > ip_address(r['stop'])): + # Everything is fine, add range to result + output.append(r) + + # Take care of last IP address range spanning from the last exclude + # address (+1) to the end of the initial configured range + if ip_address(e) == ip_address(range_last_exclude): + r = { + 'start': str(ip_address(e) + 1), + 'stop': str(range_stop) + } + output.append(r) + else: + # if we have no exclude in the whole range - we just take the range + # as it is + if not range_last_exclude: + if ra not in output: + output.append(ra) + + return output + def get_config(): dhcp = default_config_data conf = Config() @@ -327,8 +387,8 @@ def get_config(): conf.set_level('service dhcp-server shared-network-name {0} subnet {1}'.format(network, net)) subnet = { 'network': net, - 'address': str(ipaddress.ip_network(net).network_address), - 'netmask': str(ipaddress.ip_network(net).netmask), + 'address': str(ip_network(net).network_address), + 'netmask': str(ip_network(net).netmask), 'bootfile_name': '', 'bootfile_server': '', 'client_prefix_length': '', @@ -460,54 +520,12 @@ def get_config(): # IP address that needs to be excluded from DHCP lease range if conf.exists('exclude'): - # We have no need to store the exclude addresses. Exclude addresses - # are recalculated into several ranges - exclude = [] subnet['exclude'] = conf.return_values('exclude') - for addr in subnet['exclude']: - exclude.append(ipaddress.ip_address(addr)) - - # sort excluded IP addresses ascending - exclude = sorted(exclude) - - # calculate multipe ranges based on the excluded IP addresses - output = [] - for range in subnet['range']: - range_start = range['start'] - range_stop = range['stop'] - - for i in exclude: - # Excluded IP address must be in out specified range - if (i >= ipaddress.ip_address(range_start)) and (i <= ipaddress.ip_address(range_stop)): - # Build up new IP address range ending one IP address before - # our exclude address - range = { - 'start': str(range_start), - 'stop': str(i - 1) - } - # Our next IP address range will start one address after - # our exclude address - range_start = i + 1 - output.append(range) - - # Take care of last IP address range spanning from the last exclude - # address (+1) to the end of the initial configured range - if i is exclude[-1]: - last = { - 'start': str(i + 1), - 'stop': str(range_stop) - } - output.append(last) - else: - # IP address not inside search range, take range is it is - output.append(range) - - # We successfully build up a new list containing several IP address - # ranges, replace IP address range in our dictionary - subnet['range'] = output + subnet['range'] = dhcp_slice_range(subnet['exclude'], subnet['range']) # Static DHCP leases if conf.exists('static-mapping'): + addresses_for_exclude = [] for mapping in conf.list_nodes('static-mapping'): conf.set_level('service dhcp-server shared-network-name {0} subnet {1} static-mapping {2}'.format(network, net, mapping)) mapping = { @@ -525,6 +543,7 @@ def get_config(): # IP address used for this DHCP client if conf.exists('ip-address'): mapping['ip_address'] = conf.return_value('ip-address') + addresses_for_exclude.append(mapping['ip_address']) # MAC address of requesting DHCP client if conf.exists('mac-address'): @@ -543,6 +562,13 @@ def get_config(): # append static-mapping configuration to subnet list subnet['static_mapping'].append(mapping) + # Now we have all static DHCP leases - we also need to slice them + # out of our DHCP ranges to avoid ISC DHCPd warnings as: + # dhcpd: Dynamic and static leases present for 192.0.2.51. + # dhcpd: Remove host declaration DMZ_PC1 or remove 192.0.2.51 + # dhcpd: from the dynamic address pool for DMZ + subnet['range'] = dhcp_slice_range(addresses_for_exclude, subnet['range']) + # Reset config level to matching hirachy conf.set_level('service dhcp-server shared-network-name {0} subnet {1}'.format(network, net)) @@ -562,7 +588,7 @@ def get_config(): # Option format is: # <netmask>, <network-byte1>, <network-byte2>, <network-byte3>, <router-byte1>, <router-byte2>, <router-byte3> # where bytes with the value 0 are omitted. - net = ipaddress.ip_network(subnet['static_subnet']) + net = ip_network(subnet['static_subnet']) # add netmask string = str(net.prefixlen) + ',' # add network bytes @@ -682,17 +708,17 @@ def verify(dhcp): raise ConfigError('DHCP range stop address for start {0} is not defined!'.format(start)) # Start address must be inside network - if not ipaddress.ip_address(start) in ipaddress.ip_network(subnet['network']): + if not ip_address(start) in ip_network(subnet['network']): raise ConfigError('DHCP range start address {0} is not in subnet {1}\n' \ 'specified for shared network {2}!'.format(start, subnet['network'], network['name'])) # Stop address must be inside network - if not ipaddress.ip_address(stop) in ipaddress.ip_network(subnet['network']): + if not ip_address(stop) in ip_network(subnet['network']): raise ConfigError('DHCP range stop address {0} is not in subnet {1}\n' \ 'specified for shared network {2}!'.format(stop, subnet['network'], network['name'])) # Stop address must be greater or equal to start address - if not ipaddress.ip_address(stop) >= ipaddress.ip_address(start): + if not ip_address(stop) >= ip_address(start): raise ConfigError('DHCP range stop address {0} must be greater or equal\n' \ 'to the range start address {1}!'.format(stop, start)) @@ -712,7 +738,7 @@ def verify(dhcp): # Exclude addresses must be in bound for exclude in subnet['exclude']: - if not ipaddress.ip_address(exclude) in ipaddress.ip_network(subnet['network']): + if not ip_address(exclude) in ip_network(subnet['network']): raise ConfigError('Exclude IP address {0} is outside of the DHCP lease network {1}\n' \ 'under shared network {2}!'.format(exclude, subnet['network'], network['name'])) @@ -735,7 +761,7 @@ def verify(dhcp): if mapping['ip_address']: # Static IP address must be in bound - if not ipaddress.ip_address(mapping['ip_address']) in ipaddress.ip_network(subnet['network']): + if not ip_address(mapping['ip_address']) in ip_network(subnet['network']): raise ConfigError('DHCP static lease IP address {0} for static mapping {1}\n' \ 'in shared network {2} is outside DHCP lease subnet {3}!' \ .format(mapping['ip_address'], mapping['name'], network['name'], subnet['network'])) @@ -758,9 +784,9 @@ def verify(dhcp): subnets.append(subnet['network']) # Check for overlapping subnets - net = ipaddress.ip_network(subnet['network']) + net = ip_network(subnet['network']) for n in subnets: - net2 = ipaddress.ip_network(n) + net2 = ip_network(n) if (net != net2): if net.overlaps(net2): raise ConfigError('DHCP conflicting subnet ranges: {0} overlaps {1}'.format(net, net2)) |