[DHCP] IPv6 "addr6_list" change the "host" file format

[Rodolfo Alonso]

This bug could be divided in two:
1) IPv6 tags feature [1] introduces, if supported by the dnsmasq version, a new element in the "host" file, the tag:
fa:16:3e:6b:c1:97,tag:dhcpv6,host-fe32-dead-beef--5.localdomain,[fe32:dead:beef::5]

That will shift all other parameters and should be considered when parsing this file.

2) The IPv6 registers (lines in "host" file) can have more than one IP address. Each one should be registered as a new item in the set returned in [2]

[1]https://review.opendev.org/#/q/I833840e7daed2efa7efaece27cfd1ba28e0feb90
[2]https://github.com/openstack/neutron/blob/7d8f400791707e5db7839dcdf3ef4dbbd1dd39bc/neutron/agent/linux/dhcp.py#L876-L894

NOTE: the fix for this bug should be cherry-picked up to Train.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/736778

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/736778
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=8eb4955bb62ec02b7a5cb725067c6193c37f9b0e
Submitter: Zuul
Branch: master

commit 8eb4955bb62ec02b7a5cb725067c6193c37f9b0e
Author: Rodolfo Alonso Hernandez <email address hidden>
Date: Thu Jun 18 17:03:47 2020 +0000

    Fixes dnsmasq host file parsing with "addr6_list"

    This patch fixes:
    - The IPv6 tag added in the "host" file if is supported in
      dnsmasq. That shifts all other parameters in the register.
    - IPv6 registers can have more than one IP address; in this
      case, the method "_read_hosts_file_leases" should return a
      tuple per IP address.

    Change-Id: I4d0bc1eb9448366d8f1b2dacc9c5c2e4e6958253
    Closes-Bug: #1884105

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/ussuri
Review: https://review.opendev.org/737258

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/train
Review: https://review.opendev.org/737259

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/737258
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=68706b556bf5b0f65b418359c3248fe0c778c0c7
Submitter: Zuul
Branch: stable/ussuri

commit 68706b556bf5b0f65b418359c3248fe0c778c0c7
Author: Rodolfo Alonso Hernandez <email address hidden>
Date: Thu Jun 18 17:03:47 2020 +0000

    Fixes dnsmasq host file parsing with "addr6_list"

    This patch fixes:
    - The IPv6 tag added in the "host" file if is supported in
      dnsmasq. That shifts all other parameters in the register.
    - IPv6 registers can have more than one IP address; in this
      case, the method "_read_hosts_file_leases" should return a
      tuple per IP address.

    Change-Id: I4d0bc1eb9448366d8f1b2dacc9c5c2e4e6958253
    Closes-Bug: #1884105
    (cherry picked from commit 8eb4955bb62ec02b7a5cb725067c6193c37f9b0e)

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/737259
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=b4707c16918b7f2e61c522de3884525fdc3f5c91
Submitter: Zuul
Branch: stable/train

commit b4707c16918b7f2e61c522de3884525fdc3f5c91
Author: Rodolfo Alonso Hernandez <email address hidden>
Date: Thu Jun 18 17:03:47 2020 +0000

    Fixes dnsmasq host file parsing with "addr6_list"

    This patch fixes:
    - The IPv6 tag added in the "host" file if is supported in
      dnsmasq. That shifts all other parameters in the register.
    - IPv6 registers can have more than one IP address; in this
      case, the method "_read_hosts_file_leases" should return a
      tuple per IP address.

    Change-Id: I4d0bc1eb9448366d8f1b2dacc9c5c2e4e6958253
    Closes-Bug: #1884105
    (cherry picked from commit 8eb4955bb62ec02b7a5cb725067c6193c37f9b0e)
    (cherry picked from commit 68706b556bf5b0f65b418359c3248fe0c778c0c7)