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openwrt / odhcp6c

This repository is a mirror of https://git.openwrt.org/?p=project/odhcp6c.git. It is for reference only and is not active for checks-ins or reporting issues; issues should be reported at: https://bugs.openwrt.org. Pull requests will be accepted which will be merged in odhcp6c.git
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DHCPv6 Declinet not sent after duplicate address is detected. #62

Open Spantik opened 3 years ago

Spantik commented 3 years ago

RFC 8415 https://tools.ietf.org/html/rfc8415#section-18.2.8 we MUST send DHCv6 decline if we see duplicate adddress on the network. While I was testing this when linux kernel found that address is not usable as there was a duplicate address in the network odhcp6c did not send decline.

Wanted to know if this case is not handled?

Snippet from RFC.

" The client MUST perform duplicate address detection as per Section 5.4 of [RFC4862], which does list some exceptions, on each of the received addresses in any IAs on which it has not performed duplicate address detection during processing of any of the previous Reply messages from the server. The client performs the duplicate address detection before using the received addresses for any traffic. If any of the addresses are found to be in use on the link, the client sends a Decline message to the server for those addresses as described in Section 18.2.8."

hd-oppo commented 2 years ago

Found it too. For dhcpv6, there is no dad detect before use it. Otherwise, I see that like wide-dhcpv6 had already support generating DECLINE msg. Hope that there is someone to fix it.