[S-Parthiban-Selvaraj]

…ess event logging

[Copilot]

🟡 Changes recommended

Recovery can target unrelated or incorrectly prefixed addresses, report failed DAD as ready, and enter repeated DHCPv6 restart cycles.

2 open findings

• Avoid resetting the recovery guard for unchanged leases · New
• Preserve the installed prefix length during SLAAC DAD recovery · New

What changed in this PR

Adds IPv6 DAD failure visibility and automated WAN address recovery.

Changes:

• Logs IPv6 netlink address flags and DAD failures.
• Re-adds failed addresses and restarts DHCPv6 when recovery fails.
• Tracks recovery attempts across lease processing.

File	Description
source/​WanManager/​wanmgr_network_monitor.c	Logs address flags and DAD failures.
source/​WanManager/​wanmgr_interface_sm.c	Implements DAD recovery and DHCPv6 restart.
source/​WanManager/​wanmgr_dhcp_event_handler.c	Resets recovery state for lease updates.
source/​TR-181/​include/​wanmgr_dml.h	Adds DAD recovery state.

🧠 Review effort: Balanced

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[Copilot]

🟡 Changes recommended

Recovery can disrupt healthy addresses, lose address lifetimes, and report readiness with stale lease state.

4 open findings

• Scope DAD checks to the tracked IPv6 address · New
• Keep IPv6 readiness false after releasing an unusable lease · New
• Avoid resetting the recovery guard for unchanged leases
• Preserve the installed prefix length during SLAAC DAD recovery

Previously missed (2)

In code that hasn't changed since last review

Reset the DAD recovery guard at lease and connection boundaries

source/​WanManager/​wanmgr_dhcp_event_handler.c:251

This reset covers only DHCP Manager lease updates. The legacy wanmgr_handle_dhcpv6_event_data() and SLAAC netlink handler install replacement addresses without clearing the flag, and WanManager_ClearDHCPData() leaves it set during teardown. After one unsuccessful recovery, another failing address can therefore skip both recovery stages. Reset the guard at genuine new-lease/address and connection-reset boundaries in those paths as well; do not reset it merely for notifications generated by recovery itself.

Preserve IPv6 address lifetimes during DAD recovery

source/​WanManager/​wanmgr_interface_sm.c:1130

Re-adding the address without valid_lft and preferred_lft defaults both lifetimes to forever. If the installed DHCPv6 address has finite lifetimes, recovery removes its kernel expiration and deprecation deadlines. Capture the remaining lifetimes before deletion and preserve those deadlines when re-adding the address, rather than making it permanent.

🧠 Review effort: Balanced

[biju-vi]

approved