parse-nm: add a workaround for the DoT DNS option (LP: #2055148)

[daniloegea]

Netplan doesn't support DNS options such as SNI. When we parse a nameserver entry with the SNI server name, example: 1.2.3.4#name.domain, the string is added to the list of nameservers without proper parsing/validation.

This is a workaround for LP#2055148.

Description

Example:

[connection]
id=ethernet-eth123
uuid=572506e3-ab77-4c62-be96-b565984d90b3
type=ethernet
interface-name=eth123

[ethernet]

[ipv4]
dns=8.8.8.8;1.1.1.1#lxd;192.168.0.1#domain.local;
method=auto

[ipv6]
addr-gen-mode=default
dns=::1;abcd::1#domain.local;
method=auto

[proxy]

YAML without this patch:

$ LD_LIBRARY_PATH=build/src/ PYTHONPATH="$(pwd):$(pwd)/build/python-cffi"  python3 tools/keyfile_to_yaml.py /tmp/nm1.nmconnection
network:
  version: 2
  ethernets:
    NM-572506e3-ab77-4c62-be96-b565984d90b3:
      renderer: NetworkManager
      match:
        name: "eth123"
      nameservers:
        addresses:
        - 8.8.8.8
        - 1.1.1.1#lxd
        - 192.168.0.1#domain.local
        - ::1
        - abcd::1#domain.local
      dhcp4: true
      dhcp6: true
      wakeonlan: true
      networkmanager:
        uuid: "572506e3-ab77-4c62-be96-b565984d90b3"
        name: "ethernet-eth123"
        passthrough:
          ethernet._: ""
          ipv6.addr-gen-mode: "default"
          ipv6.ip6-privacy: "-1"
          proxy._: ""

YAML with this patch:

$ LD_LIBRARY_PATH=build/src/ PYTHONPATH="$(pwd):$(pwd)/build/python-cffi"  python3 tools/keyfile_to_yaml.py /tmp/nm1.nmconnection
network:
  version: 2
  ethernets:
    NM-572506e3-ab77-4c62-be96-b565984d90b3:
      renderer: NetworkManager
      match:
        name: "eth123"
      dhcp4: true
      dhcp6: true
      wakeonlan: true
      networkmanager:
        uuid: "572506e3-ab77-4c62-be96-b565984d90b3"
        name: "ethernet-eth123"
        passthrough:
          ethernet._: ""
          ipv4.dns: "8.8.8.8;1.1.1.1#lxd;192.168.0.1#domain.local;"
          ipv6.addr-gen-mode: "default"
          ipv6.dns: "::1;abcd::1#domain.local;"
          ipv6.ip6-privacy: "-1"
          proxy._: ""

Here is a test with Network Manager and combinations of IPv4 and IPv6 with and without the SNI string:

root@test:~# nmcli con add type dummy ifname dummy0 ipv4.dns 1.1.1.1,192.168.0.1#test.lxd ipv6.dns ::1,abcd::1#test.lxd
Connection 'dummy-dummy0' (be1d82a1-fa3a-4587-b100-196376c0da3a) successfully added.
root@test:~# nmcli con add type dummy ifname dummy1 ipv4.dns 1.1.1.1,192.168.0.1#test.lxd ipv6.dns ::1,abcd::1
Connection 'dummy-dummy1' (6cf3a6c9-716c-462a-bf6f-0509406d90a0) successfully added.
root@test:~# nmcli con add type dummy ifname dummy2 ipv4.dns 1.1.1.1,192.168.0.1 ipv6.dns ::1,abcd::1#test.lxd
Connection 'dummy-dummy2' (04f55279-cd31-49b6-bcfa-b01e3354b85b) successfully added.
root@test:~# nmcli con add type dummy ifname dummy3 ipv4.dns 1.1.1.1,192.168.0.1 ipv6.dns ::1,abcd::1
Connection 'dummy-dummy3' (2eb2a6af-5c92-44c9-b978-15ac262c73a7) successfully added.

root@test:~# netplan get
network:
  version: 2
  renderer: networkd
  ethernets:
    enp5s0:
      dhcp4: true
      dhcp6: false
      link-local:
      - ipv4
      - ipv6
  dummy-devices:
    NM-04f55279-cd31-49b6-bcfa-b01e3354b85b:
      renderer: NetworkManager
      nameservers:
        addresses:
        - 1.1.1.1
        - 192.168.0.1
      dhcp4: true
      dhcp6: true
      networkmanager:
        uuid: "04f55279-cd31-49b6-bcfa-b01e3354b85b"
        name: "dummy-dummy2"
        passthrough:
          connection.interface-name: "dummy2"
          dummy._: ""
          ipv6.addr-gen-mode: "default"
          ipv6.dns: "::1;abcd::1#test.lxd;"
          ipv6.ip6-privacy: "-1"
          proxy._: ""
    NM-2eb2a6af-5c92-44c9-b978-15ac262c73a7:
      renderer: NetworkManager
      nameservers:
        addresses:
        - 1.1.1.1
        - 192.168.0.1
        - ::1
        - abcd::1
      dhcp4: true
      dhcp6: true
      networkmanager:
        uuid: "2eb2a6af-5c92-44c9-b978-15ac262c73a7"
        name: "dummy-dummy3"
        passthrough:
          connection.interface-name: "dummy3"
          dummy._: ""
          ipv6.addr-gen-mode: "default"
          ipv6.ip6-privacy: "-1"
          proxy._: ""
    NM-6cf3a6c9-716c-462a-bf6f-0509406d90a0:
      renderer: NetworkManager
      nameservers:
        addresses:
        - ::1
        - abcd::1
      dhcp4: true
      dhcp6: true
      networkmanager:
        uuid: "6cf3a6c9-716c-462a-bf6f-0509406d90a0"
        name: "dummy-dummy1"
        passthrough:
          connection.interface-name: "dummy1"
          dummy._: ""
          ipv4.dns: "1.1.1.1;192.168.0.1#test.lxd;"
          ipv6.addr-gen-mode: "default"
          ipv6.ip6-privacy: "-1"
          proxy._: ""
    NM-be1d82a1-fa3a-4587-b100-196376c0da3a:
      renderer: NetworkManager
      dhcp4: true
      dhcp6: true
      networkmanager:
        uuid: "be1d82a1-fa3a-4587-b100-196376c0da3a"
        name: "dummy-dummy0"
        passthrough:
          connection.interface-name: "dummy0"
          dummy._: ""
          ipv4.dns: "1.1.1.1;192.168.0.1#test.lxd;"
          ipv6.addr-gen-mode: "default"
          ipv6.dns: "::1;abcd::1#test.lxd;"
          ipv6.ip6-privacy: "-1"
          proxy._: ""

Checklist

• Runs make check successfully.
• Retains 100% code coverage (make check-coverage).
• New/changed keys in YAML format are documented.
• (Optional) Adds example YAML for new feature.
• (Optional) Closes an open bug in Launchpad.

[slyon]

lgtm. Can be merge once the autopkgtests are green.

Could you also please prepare a distro patch for Debian, against https://salsa.debian.org/debian/netplan.io ?