RDKB-66284 : retry DHCPv6 start when link-local DAD is pending

[aadhithan01]

Reason for change: On boot, DhcpMgr_checkLinkLocalAddress() returns FALSE when erouter0 link-local address DAD has not completed within the 5 s wait window. The previous code had only a comment //Link local failed. Retry with no actual retry logic, leaving dibbler permanently unstarted and IPv6 down for the entire device uptime (observed 3+ days on TCXB7/TCXB8 running 8.6p1s5, RDKB-66284).

Fix: re-enqueue a Selfheal_ClientRestart message via DhcpMgr_OpenQueueEnsureThread so the per-interface controller retries dibbler startup once DAD completes. DhcpMgr_checkLinkLocalAddress blocks up to INTF_V6LL_TIMEOUT_IN_MSEC per call, so the retry is naturally rate-limited without an explicit counter.

Test Procedure: Only for test purpose

Risks: Low

Priority: P2

Signed-off-by: 64963550+aadhithan01@users.noreply.github.com

[Copilot]

Pull request overview

This PR addresses a boot-time failure mode where the DHCPv6 client (dibbler) can remain permanently stopped if the interface’s IPv6 link-local address is still in DAD/tentative state beyond the current wait window.

Changes:

• Adds retry behavior when DhcpMgr_checkLinkLocalAddress() times out by re-enqueueing a Selfheal_ClientRestart control message to the per-interface controller.
• Improves inline documentation/logging around the link-local readiness gating for DHCPv6 client start.

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[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

Comments suppressed due to low confidence (1)

source/DHCPMgrUtils/dhcpmgr_controller.c:820

• The Selfheal_ClientRestart enqueue block here duplicates the same message construction used elsewhere (e.g., processKilled() in this file at dhcpmgr_controller.c:1218-1281). Duplicating this logic in multiple places makes future changes error-prone (e.g., if the message shape or ParamName changes). Consider factoring this into a small static helper (e.g., DhcpMgr_EnqueueSelfhealRestart(ifname, DML_DHCPV6)) and reusing it at all call sites.

                    dhcp_info_t retry_info;
                    memset(&retry_info, 0, sizeof(retry_info));
                    strncpy(retry_info.if_name, pDhcp6c->Cfg.Interface, MAX_STR_LEN - 1);
                    retry_info.if_name[MAX_STR_LEN - 1] = '\0';
                    retry_info.dhcpType = DML_DHCPV6;
                    strncpy(retry_info.ParamName, "Selfheal_ClientRestart", sizeof(retry_info.ParamName) - 1);
                    retry_info.ParamName[sizeof(retry_info.ParamName) - 1] = '\0';
                    retry_info.value.bValue = FALSE;
                    if (DhcpMgr_OpenQueueEnsureThread(retry_info) != 0)

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

Suppressed comments (3)

source/DHCPMgrUtils/dhcpmgr_controller.c:805

• Same as above: this line references checkLinkLocalAddress() but the actual function is DhcpMgr_checkLinkLocalAddress().

                     * checkLinkLocalAddress() blocks up to INTF_V6LL_TIMEOUT_IN_MSEC
                     * per call, so this retry is naturally rate-limited.

source/DHCPMgrUtils/dhcpmgr_controller.c:802

• In this comment block, the function name is referred to as checkLinkLocalAddress(), but the actual function is DhcpMgr_checkLinkLocalAddress(). Keeping the exact name here will avoid confusion when grepping/debugging.

This issue also appears on line 804 of the same file.

                     * checkLinkLocalAddress() has already force-toggled disable_ipv6
                     * to regenerate the link-local address, but that completes
                     * asynchronously. Re-enqueue a restart so the client is started
                     * once the link-local address is ready, instead of leaving it
                     * permanently stopped (Info.Status stays Disabled and dibbler is

source/DHCPMgrUtils/dhcpmgr_controller.c:815

• Use sizeof(retry_info.if_name) for the copy/terminator bounds instead of MAX_STR_LEN to keep this safe even if the struct field size changes independently of the macro.

                    strncpy(retry_info.if_name, pDhcp6c->Cfg.Interface, MAX_STR_LEN - 1);
                    retry_info.if_name[MAX_STR_LEN - 1] = '\0';