[Bug 1907306] Re: networkd dhcpv4 client never attempts more than 2 renew and 2 rebind

Dan Streetman 1907306 at bugs.launchpad.net
Wed Jan 13 20:23:11 UTC 2021 

groovy:

root at lp1907306-g:~# dpkg -l systemd|grep systemd
ii  systemd        246.6-1ubuntu1.1 amd64        system and service manager
root at lp1907306-g:~# journalctl -b -u systemd-networkd | grep 'ifindex 3'
Jan 13 18:57:26 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): STARTED on ifindex 3
root at lp1907306-g:~# journalctl -b -u systemd-networkd | grep 0x39b455d6
Jan 13 18:57:26 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): STARTED on ifindex 3
Jan 13 18:57:26 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): DISCOVER
Jan 13 18:57:26 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): OFFER
Jan 13 18:57:26 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): REQUEST (requesting)
Jan 13 18:57:26 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): ACK
Jan 13 18:57:26 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): lease expires in 59min 59s
Jan 13 18:57:26 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): T2 expires in 52min 30s
Jan 13 18:57:26 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): T1 expires in 29min 59s
Jan 13 19:27:25 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): REQUEST (renewing)
Jan 13 19:38:41 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): REQUEST (renewing)
Jan 13 19:44:18 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): REQUEST (renewing)
Jan 13 19:47:07 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): REQUEST (renewing)
Jan 13 19:48:32 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): REQUEST (renewing)
Jan 13 19:49:32 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): REQUEST (renewing)
Jan 13 19:49:56 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): REQUEST (rebinding)
Jan 13 19:53:41 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): REQUEST (rebinding)
Jan 13 19:55:33 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): REQUEST (rebinding)
Jan 13 19:56:33 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): REQUEST (rebinding)
Jan 13 19:57:26 lp1907306-g systemd-networkd[22430]: DHCP CLIENT (0x39b455d6): EXPIRED


focal:

root at lp1907306-f:~# dpkg -l systemd|grep systemd
ii  systemd        245.4-4ubuntu3.4 amd64        system and service manager
root at lp1907306-f:~# journalctl -b -u systemd-networkd | grep 'ifindex 3'
Jan 13 18:57:24 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): STARTED on ifindex 3
root at lp1907306-f:~# journalctl -b -u systemd-networkd | grep 0xf2c32973
Jan 13 18:57:24 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): STARTED on ifindex 3
Jan 13 18:57:24 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): DISCOVER
Jan 13 18:57:24 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): OFFER
Jan 13 18:57:24 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): REQUEST (requesting)
Jan 13 18:57:24 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): ACK
Jan 13 18:57:24 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): lease expires in 59min 59s
Jan 13 18:57:24 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): T2 expires in 52min 29s
Jan 13 18:57:24 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): T1 expires in 30min
Jan 13 19:27:24 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): REQUEST (renewing)
Jan 13 19:38:39 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): REQUEST (renewing)
Jan 13 19:44:16 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): REQUEST (renewing)
Jan 13 19:47:04 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): REQUEST (renewing)
Jan 13 19:48:29 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): REQUEST (renewing)
Jan 13 19:49:29 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): REQUEST (renewing)
Jan 13 19:49:53 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): REQUEST (rebinding)
Jan 13 19:53:38 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): REQUEST (rebinding)
Jan 13 19:55:31 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): REQUEST (rebinding)
Jan 13 19:56:31 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): REQUEST (rebinding)
Jan 13 19:57:24 lp1907306-f systemd-networkd[23394]: DHCP CLIENT (0xf2c32973): EXPIRED


bionic:

root at lp1907306-b:~# dpkg -l systemd|grep systemd
ii  systemd        237-3ubuntu10.44 amd64        system and service manager
root at lp1907306-b:~# journalctl -b -u systemd-networkd | grep 'ifindex 3'
Jan 13 18:57:22 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): STARTED on ifindex 3
root at lp1907306-b:~# journalctl -b -u systemd-networkd | grep 0x9b4dacd8
Jan 13 18:57:22 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): STARTED on ifindex 3
Jan 13 18:57:22 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): DISCOVER
Jan 13 18:57:22 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): OFFER
Jan 13 18:57:22 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): REQUEST (requesting)
Jan 13 18:57:22 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): ACK
Jan 13 18:57:22 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): lease expires in 59min 59s
Jan 13 18:57:22 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): T2 expires in 52min 30s
Jan 13 18:57:22 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): T1 expires in 30min
Jan 13 19:27:22 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): REQUEST (renewing)
Jan 13 19:38:37 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): REQUEST (renewing)
Jan 13 19:44:15 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): REQUEST (renewing)
Jan 13 19:47:03 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): REQUEST (renewing)
Jan 13 19:48:28 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): REQUEST (renewing)
Jan 13 19:49:28 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): REQUEST (renewing)
Jan 13 19:49:52 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): REQUEST (rebinding)
Jan 13 19:53:37 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): REQUEST (rebinding)
Jan 13 19:55:29 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): REQUEST (rebinding)
Jan 13 19:56:29 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): REQUEST (rebinding)
Jan 13 19:57:22 lp1907306-b systemd-networkd[25911]: DHCP CLIENT (0x9b4dacd8): EXPIRED


** Tags removed: verification-needed verification-needed-bionic verification-needed-focal verification-needed-groovy
** Tags added: verification-done verification-done-bionic verification-done-focal verification-done-groovy

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https://bugs.launchpad.net/bugs/1907306

Title:
  networkd dhcpv4 client never attempts more than 2 renew and 2 rebind

Status in systemd:
  Fix Released
Status in systemd package in Ubuntu:
  In Progress
Status in systemd source package in Bionic:
  Fix Committed
Status in systemd source package in Focal:
  Fix Committed
Status in systemd source package in Groovy:
  Fix Committed
Status in systemd source package in Hirsute:
  In Progress

Bug description:
  [impact]

  networkd dhcpv4 client never attempts more than 2 renew and 2 rebind

  [test case]

  configure an interface to use dhcpv4; acquire a dhcpv4 address, then
  stop the dhcpv4 server, and wait for the networkd client to perform
  its renewals and rebinds before expiring the lease

  using a 20 minute lease time as an example (all times are approximate
  due to RFC-mandated random 'fuzz' time of -1 to +1 sec):

  the current behavior would be to sent renew requests at:

  10:00
  13:45

  and then rebind requests at:

  17:30
  18:45

  then the lease would expire at 20:00

  the correct/new behavior should be renew requests at:

  10:00
  13:45
  15:37
  16:37

  and then rebind requests at:

  17:30
  18:45
  19:45

  and then lease expiration at 20:00.

  longer lease times would increase the number of retransmissions.

  [regression potential]

  any regression would likely result in problems receiving and/or
  maintaining a dhcpv4 address

  [scope]

  this is needed in b/f/g/h.

  this was fixed upstream in:
  https://github.com/systemd/systemd/pull/17908

  that was just added, so this is not fixed in any ubuntu release yet.

  technically, this is needed in x as well, however I don't plan to
  backport to x since 1) it reaches ESM soon and 2) the default network
  management tool in x is ifupdown, not systemd-networkd.

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