Page Menu
Home
VyOS Platform
Search
Configure Global Search
Log In
Files
F4979200
nat_cgnat.py
No One
Temporary
Actions
Download File
Edit File
Delete File
View Transforms
Subscribe
Flag For Later
Award Token
Size
11 KB
Referenced Files
None
Subscribers
None
nat_cgnat.py
View Options
#!/usr/bin/env python3
#
# Copyright (C) 2024 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
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# 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
ipaddress
import
jmespath
import
os
from
sys
import
exit
from
vyos.config
import
Config
from
vyos.template
import
render
from
vyos.utils.process
import
cmd
from
vyos.utils.process
import
run
from
vyos
import
ConfigError
from
vyos
import
airbag
airbag
.
enable
()
nftables_cgnat_config
=
'/run/nftables-cgnat.nft'
class
IPOperations
:
def
__init__
(
self
,
ip_prefix
:
str
):
self
.
ip_prefix
=
ip_prefix
self
.
ip_network
=
ipaddress
.
ip_network
(
ip_prefix
)
if
'/'
in
ip_prefix
else
None
def
get_ips_count
(
self
)
->
int
:
"""Returns the number of IPs in a prefix or range.
Example:
% ip = IPOperations('192.0.2.0/30')
% ip.get_ips_count()
4
% ip = IPOperations('192.0.2.0-192.0.2.2')
% ip.get_ips_count()
3
"""
if
'-'
in
self
.
ip_prefix
:
start_ip
,
end_ip
=
self
.
ip_prefix
.
split
(
'-'
)
start_ip
=
ipaddress
.
ip_address
(
start_ip
)
end_ip
=
ipaddress
.
ip_address
(
end_ip
)
return
int
(
end_ip
)
-
int
(
start_ip
)
+
1
elif
'/31'
in
self
.
ip_prefix
:
return
2
elif
'/32'
in
self
.
ip_prefix
:
return
1
else
:
return
sum
(
1
for
_
in
[
self
.
ip_network
.
network_address
]
+
list
(
self
.
ip_network
.
hosts
())
+
[
self
.
ip_network
.
broadcast_address
]
)
def
convert_prefix_to_list_ips
(
self
)
->
list
:
"""Converts a prefix or IP range to a list of IPs including the network and broadcast addresses.
Example:
% ip = IPOperations('192.0.2.0/30')
% ip.convert_prefix_to_list_ips()
['192.0.2.0', '192.0.2.1', '192.0.2.2', '192.0.2.3']
%
% ip = IPOperations('192.0.0.1-192.0.2.5')
% ip.convert_prefix_to_list_ips()
['192.0.2.1', '192.0.2.2', '192.0.2.3', '192.0.2.4', '192.0.2.5']
"""
if
'-'
in
self
.
ip_prefix
:
start_ip
,
end_ip
=
self
.
ip_prefix
.
split
(
'-'
)
start_ip
=
ipaddress
.
ip_address
(
start_ip
)
end_ip
=
ipaddress
.
ip_address
(
end_ip
)
return
[
str
(
ipaddress
.
ip_address
(
ip
))
for
ip
in
range
(
int
(
start_ip
),
int
(
end_ip
)
+
1
)
]
elif
'/31'
in
self
.
ip_prefix
:
return
[
str
(
ip
)
for
ip
in
[
self
.
ip_network
.
network_address
,
self
.
ip_network
.
broadcast_address
,
]
]
elif
'/32'
in
self
.
ip_prefix
:
return
[
str
(
self
.
ip_network
.
network_address
)]
else
:
return
[
str
(
ip
)
for
ip
in
[
self
.
ip_network
.
network_address
]
+
list
(
self
.
ip_network
.
hosts
())
+
[
self
.
ip_network
.
broadcast_address
]
]
def
generate_port_rules
(
external_hosts
:
list
,
internal_hosts
:
list
,
port_count
:
int
,
global_port_range
:
str
=
'1024-65535'
,
)
->
list
:
"""Generates list of nftables rules for the batch file."""
rules
=
[]
proto_map_elements
=
[]
other_map_elements
=
[]
start_port
,
end_port
=
map
(
int
,
global_port_range
.
split
(
'-'
))
total_possible_ports
=
(
end_port
-
start_port
)
+
1
# Calculate the required number of ports per host
required_ports_per_host
=
port_count
# Check if there are enough external addresses for all internal hosts
if
required_ports_per_host
*
len
(
internal_hosts
)
>
total_possible_ports
*
len
(
external_hosts
):
raise
ConfigError
(
"Not enough ports available for the specified parameters!"
)
current_port
=
start_port
current_external_index
=
0
for
internal_host
in
internal_hosts
:
external_host
=
external_hosts
[
current_external_index
]
next_end_port
=
current_port
+
required_ports_per_host
-
1
# If the port range exceeds the end_port, move to the next external host
while
next_end_port
>
end_port
:
current_external_index
=
(
current_external_index
+
1
)
%
len
(
external_hosts
)
external_host
=
external_hosts
[
current_external_index
]
current_port
=
start_port
next_end_port
=
current_port
+
required_ports_per_host
-
1
# Ensure the same port is not assigned to the same external host
if
any
(
rule
.
endswith
(
f
'{external_host}:{current_port}-{next_end_port}'
)
for
rule
in
rules
):
raise
ConfigError
(
"Not enough ports available for the specified parameters"
)
proto_map_elements
.
append
(
f
'{internal_host} : {external_host} . {current_port}-{next_end_port}'
)
other_map_elements
.
append
(
f
'{internal_host} : {external_host}'
)
current_port
=
next_end_port
+
1
if
current_port
>
end_port
:
current_port
=
start_port
current_external_index
+=
1
# Move to the next external host
return
[
proto_map_elements
,
other_map_elements
]
def
get_config
(
config
=
None
):
if
config
:
conf
=
config
else
:
conf
=
Config
()
base
=
[
'nat'
,
'cgnat'
]
config
=
conf
.
get_config_dict
(
base
,
get_first_key
=
True
,
key_mangling
=
(
'-'
,
'_'
),
no_tag_node_value_mangle
=
True
,
with_recursive_defaults
=
True
,
)
return
config
def
verify
(
config
):
# bail out early - looks like removal from running config
if
not
config
:
return
None
if
'pool'
not
in
config
:
raise
ConfigError
(
f
'Pool must be defined!'
)
if
'rule'
not
in
config
:
raise
ConfigError
(
f
'Rule must be defined!'
)
for
pool
in
(
'external'
,
'internal'
):
if
pool
not
in
config
[
'pool'
]:
raise
ConfigError
(
f
'{pool} pool must be defined!'
)
for
pool_name
,
pool_config
in
config
[
'pool'
][
pool
]
.
items
():
if
'range'
not
in
pool_config
:
raise
ConfigError
(
f
'Range for "{pool} pool {pool_name}" must be defined!'
)
external_pools_query
=
"keys(pool.external)"
external_pools
:
list
=
jmespath
.
search
(
external_pools_query
,
config
)
internal_pools_query
=
"keys(pool.internal)"
internal_pools
:
list
=
jmespath
.
search
(
internal_pools_query
,
config
)
used_external_pools
=
{}
used_internal_pools
=
{}
for
rule
,
rule_config
in
config
[
'rule'
]
.
items
():
if
'source'
not
in
rule_config
:
raise
ConfigError
(
f
'Rule "{rule}" source pool must be defined!'
)
if
'pool'
not
in
rule_config
[
'source'
]:
raise
ConfigError
(
f
'Rule "{rule}" source pool must be defined!'
)
if
'translation'
not
in
rule_config
:
raise
ConfigError
(
f
'Rule "{rule}" translation pool must be defined!'
)
# Check if pool exists
internal_pool
=
rule_config
[
'source'
][
'pool'
]
if
internal_pool
not
in
internal_pools
:
raise
ConfigError
(
f
'Internal pool "{internal_pool}" does not exist!'
)
external_pool
=
rule_config
[
'translation'
][
'pool'
]
if
external_pool
not
in
external_pools
:
raise
ConfigError
(
f
'External pool "{external_pool}" does not exist!'
)
# Check pool duplication in different rules
if
external_pool
in
used_external_pools
:
raise
ConfigError
(
f
'External pool "{external_pool}" is already used in rule '
f
'{used_external_pools[external_pool]} and cannot be used in '
f
'rule {rule}!'
)
if
internal_pool
in
used_internal_pools
:
raise
ConfigError
(
f
'Internal pool "{internal_pool}" is already used in rule '
f
'{used_internal_pools[internal_pool]} and cannot be used in '
f
'rule {rule}!'
)
used_external_pools
[
external_pool
]
=
rule
used_internal_pools
[
internal_pool
]
=
rule
def
generate
(
config
):
if
not
config
:
return
None
proto_maps
=
[]
other_maps
=
[]
for
rule
,
rule_config
in
config
[
'rule'
]
.
items
():
ext_pool_name
:
str
=
rule_config
[
'translation'
][
'pool'
]
int_pool_name
:
str
=
rule_config
[
'source'
][
'pool'
]
external_ranges
:
list
=
[
range
for
range
in
config
[
'pool'
][
'external'
][
ext_pool_name
][
'range'
]]
internal_ranges
:
list
=
[
range
for
range
in
config
[
'pool'
][
'internal'
][
int_pool_name
][
'range'
]]
external_list_hosts_count
=
[]
external_list_hosts
=
[]
internal_list_hosts_count
=
[]
internal_list_hosts
=
[]
for
ext_range
in
external_ranges
:
# External hosts count
e_count
=
IPOperations
(
ext_range
)
.
get_ips_count
()
external_list_hosts_count
.
append
(
e_count
)
# External hosts list
e_hosts
=
IPOperations
(
ext_range
)
.
convert_prefix_to_list_ips
()
external_list_hosts
.
extend
(
e_hosts
)
for
int_range
in
internal_ranges
:
# Internal hosts count
i_count
=
IPOperations
(
int_range
)
.
get_ips_count
()
internal_list_hosts_count
.
append
(
i_count
)
# Internal hosts list
i_hosts
=
IPOperations
(
int_range
)
.
convert_prefix_to_list_ips
()
internal_list_hosts
.
extend
(
i_hosts
)
external_host_count
=
sum
(
external_list_hosts_count
)
internal_host_count
=
sum
(
internal_list_hosts_count
)
ports_per_user
=
int
(
jmespath
.
search
(
f
'pool.external."{ext_pool_name}".per_user_limit.port'
,
config
)
)
external_port_range
:
str
=
jmespath
.
search
(
f
'pool.external."{ext_pool_name}".external_port_range'
,
config
)
rule_proto_maps
,
rule_other_maps
=
generate_port_rules
(
external_list_hosts
,
internal_list_hosts
,
ports_per_user
,
external_port_range
)
proto_maps
.
extend
(
rule_proto_maps
)
other_maps
.
extend
(
rule_other_maps
)
config
[
'proto_map_elements'
]
=
', '
.
join
(
proto_maps
)
config
[
'other_map_elements'
]
=
', '
.
join
(
other_maps
)
render
(
nftables_cgnat_config
,
'firewall/nftables-cgnat.j2'
,
config
)
# dry-run newly generated configuration
tmp
=
run
(
f
'nft --check --file {nftables_cgnat_config}'
)
if
tmp
>
0
:
raise
ConfigError
(
'Configuration file errors encountered!'
)
def
apply
(
config
):
if
not
config
:
# Cleanup cgnat
cmd
(
'nft delete table ip cgnat'
)
if
os
.
path
.
isfile
(
nftables_cgnat_config
):
os
.
unlink
(
nftables_cgnat_config
)
return
None
cmd
(
f
'nft --file {nftables_cgnat_config}'
)
if
__name__
==
'__main__'
:
try
:
c
=
get_config
()
verify
(
c
)
generate
(
c
)
apply
(
c
)
except
ConfigError
as
e
:
print
(
e
)
exit
(
1
)
File Metadata
Details
Attached
Mime Type
text/x-script.python
Expires
Thu, Oct 31, 9:57 PM (1 d, 20 h)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
895263
Default Alt Text
nat_cgnat.py (11 KB)
Attached To
Mode
rVYOSONEX vyos-1x
Attached
Detach File
Event Timeline
Log In to Comment