[FS#1462] odhcp6c fails to renew and rebind addresses

[LEDE Bugs]

The following task has a new comment added:

FS#1462 - odhcp6c fails to renew and rebind addresses
User who did this - Hans Dedecker (dedeckeh)

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odhcp6c handles the case where the lifetime is set to zero; see https://git.openwrt.org/?p=project/odhcp6c.git;a=blob;f=src/odhcp6c.c;h=48e3dee1cea2c9545e03583e9dab5578698d20bf;hb=HEAD#l744. It will remove the entry if the lifetime is set to 0 and if no statefull address/prefix entries are left it will switch to sending solicit messages.
But in this particular case the DHCPv6 server is not sending an IA_PREFIX in the reply which means it has to follow the following requirement from RFC3315

When the client receives a Reply message in response to a Renew or
Rebind message, the client examines each IA independently.  For each
IA in the original Renew or Rebind message, the client:

   -  sends a Request message if the IA contained a Status Code option
      with the NoBinding status (and does not send any additional
      Renew/Rebind messages)

   -  sends a Renew/Rebind if the IA is not in the Reply message

   -  otherwise accepts the information in the IA
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More information can be found at the following URL:
https://bugs.openwrt.org/index.php?do=details&task_id=1462#comment4554