diff options
| -rwxr-xr-x | src/conf_mode/dhcp_server.py | 107 |
1 files changed, 63 insertions, 44 deletions
diff --git a/src/conf_mode/dhcp_server.py b/src/conf_mode/dhcp_server.py index 89618f31d..268afc582 100755 --- a/src/conf_mode/dhcp_server.py +++ b/src/conf_mode/dhcp_server.py @@ -249,6 +249,68 @@ 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 (ipaddress.ip_address(e) >= ipaddress.ip_address(range_start)) and \ + (ipaddress.ip_address(e) <= ipaddress.ip_address(range_stop)): + range_last_exclude = e + + for e in exclude_list: + if (ipaddress.ip_address(e) >= ipaddress.ip_address(range_start)) and \ + (ipaddress.ip_address(e) <= ipaddress.ip_address(range_stop)): + + # Build new IP address range ending one IP address before exclude address + r = { + 'start' : range_start, + 'stop' : str(ipaddress.ip_address(e) -1) + } + # On the next run our IP address range will start one address after the exclude address + range_start = str(ipaddress.ip_address(e) + 1) + + # on subsequent exclude addresses we can not + # append them to our output + if not (ipaddress.ip_address(r['start']) > ipaddress.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 ipaddress.ip_address(e) == ipaddress.ip_address(range_last_exclude): + r = { + 'start': str(ipaddress.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() @@ -456,51 +518,8 @@ 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'): |