116 lines
4.4 KiB
Python
116 lines
4.4 KiB
Python
#
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# Copyright (c) 2022 Pim van Pelt
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at:
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# http://www.apache.org/licenses/LICENSE-2.0
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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""" A vppcfg configuration module that handles addresses """
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import ipaddress
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def get_all_addresses_except_ifname(yaml, except_ifname):
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"""Return a list of all ipaddress.ip_interface() instances in the entire config,
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except for those that belong to 'ifname'.
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"""
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ret = []
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if "interfaces" in yaml:
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for ifname, iface in yaml["interfaces"].items():
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if ifname == except_ifname:
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continue
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if "addresses" in iface:
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for addr in iface["addresses"]:
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ret.append(ipaddress.ip_interface(addr))
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if "sub-interfaces" in iface:
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for subid, sub_iface in iface["sub-interfaces"].items():
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sub_ifname = f"{ifname}.{int(subid)}"
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if sub_ifname == except_ifname:
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continue
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if "addresses" in sub_iface:
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for addr in sub_iface["addresses"]:
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ret.append(ipaddress.ip_interface(addr))
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if "loopbacks" in yaml:
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for ifname, iface in yaml["loopbacks"].items():
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if ifname == except_ifname:
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continue
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if "addresses" in iface:
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for addr in iface["addresses"]:
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ret.append(ipaddress.ip_interface(addr))
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if "bridgedomains" in yaml:
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for ifname, iface in yaml["bridgedomains"].items():
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if ifname == except_ifname:
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continue
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if "addresses" in iface:
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for addr in iface["addresses"]:
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ret.append(ipaddress.ip_interface(addr))
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return ret
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def is_allowed(yaml, ifname, iface_addresses, ip_interface):
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"""Returns True if there is at most one occurence of the ip_interface (an IPv4/IPv6 prefix+len)
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in the entire config. That said, we need the 'iface_addresses' because VPP is a bit fickle in
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this regard.
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IP addresses from the same prefix/len can be added to a given interface (ie 192.0.2.1/24 and
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192.0.2.2/24), but other than that, any prefix can not occur as a more-specific or less-specific
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of any other interface.
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So, we will allow:
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- any ip_interface that is of equal network/len of existing one(s) _on the same interface_
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And, we will reject
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- any ip_interface that is a more specific of any existing one
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- any ip_interface that is a less specific of any existing one
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Examples:
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vpp# set interface ip address loop0 192.0.2.1/24
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vpp# set interface ip address loop0 192.0.2.2/24
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vpp# set interface ip address loop0 192.0.2.1/29
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set interface ip address: failed to add 192.0.2.1/29 on loop0 which conflicts with 192.0.2.1/24 for interface loop0
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vpp# set interface ip address loop0 192.0.2.3/23
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set interface ip address: failed to add 192.0.2.3/23 on loop0 which conflicts with 192.0.2.1/24 for interface loop0
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"""
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all_other_addresses = get_all_addresses_except_ifname(yaml, ifname)
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my_ip_network = ipaddress.ip_network(ip_interface, strict=False)
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for ipi in all_other_addresses:
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if ipi.version != my_ip_network.version:
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continue
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if ipaddress.ip_network(ipi, strict=False) == my_ip_network:
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return False
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if ipaddress.ip_network(ipi, strict=False).subnet_of(my_ip_network):
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return False
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if my_ip_network.subnet_of(ipaddress.ip_network(ipi, strict=False)):
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return False
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for addr in iface_addresses:
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ipi = ipaddress.ip_interface(addr)
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if ipi.version != my_ip_network.version:
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continue
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if ipaddress.ip_network(ipi, strict=False) == my_ip_network:
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return True
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if ipaddress.ip_network(ipi, strict=False).subnet_of(my_ip_network):
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return False
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if my_ip_network.subnet_of(ipaddress.ip_network(ipi, strict=False)):
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return False
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return True
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