{"id":12814,"date":"2026-03-13T09:00:01","date_gmt":"2026-03-13T09:00:01","guid":{"rendered":"https:\/\/developer.rdkcentral.com\/documentation\/?page_id=12814"},"modified":"2026-03-13T09:01:05","modified_gmt":"2026-03-13T09:01:05","slug":"dhcp-recovery-handler","status":"publish","type":"page","link":"https:\/\/developer.rdkcentral.com\/documentation\/documentation\/rdk_broadband_documentation\/components\/dhcp-client-manager\/dhcp-recovery-handler\/","title":{"rendered":"DHCP Recovery Handler"},"content":{"rendered":"\n<p>The DHCP Recovery Handler provides persistence and recovery functionality for the DHCP Client Manager. It ensures that DHCP client state and lease information survive system restarts, crashes, and other service interruptions. The component implements a comprehensive recovery system that monitors client processes, stores lease data, and restores operational state upon system restart.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-Architecture\">Architecture<\/h2>\n\n\n\n<p>The recovery handler implements a multi-layered persistence and monitoring architecture:<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510     \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510     \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502   Process Monitor   \u2502\u2500\u2500\u2500\u2500\u25ba\u2502  Recovery Handler   \u2502\u2500\u2500\u2500\u2500\u25ba\u2502  Persistence Layer  \u2502\n\u2502                     \u2502     \u2502                     \u2502     \u2502                     \u2502\n\u2502 \u2022 PID Tracking      \u2502     \u2502 \u2022 State Management  \u2502     \u2502 \u2022 File Storage      \u2502\n\u2502 \u2022 Health Checks     \u2502     \u2502 \u2022 Recovery Logic    \u2502     \u2502 \u2022 Data Integrity    \u2502\n\u2502 \u2022 Event Detection   \u2502     \u2502 \u2022 Restart Control   \u2502     \u2502 \u2022 Atomic Operations \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518     \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518     \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n                                      \u2502\n                                      \u25bc\n\u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510     \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510     \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510\n\u2502   System Startup    \u2502\u25c4\u2500\u2500\u2500\u2500\u2502  Recovery Process   \u2502\u2500\u2500\u2500\u2500\u25ba\u2502  Client Restoration \u2502\n\u2502                     \u2502     \u2502                     \u2502     \u2502                     \u2502\n\u2502 \u2022 Service Init      \u2502     \u2502 \u2022 Data Validation   \u2502     \u2502 \u2022 State Restoration \u2502\n\u2502 \u2022 File System Check \u2502     \u2502 \u2022 Lease Recovery    \u2502     \u2502 \u2022 Process Restart   \u2502\n\u2502 \u2022 Resource Alloc    \u2502     \u2502 \u2022 Configuration     \u2502     \u2502 \u2022 TR-181 Update     \u2502\n\u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518     \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518     \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518\n<\/pre>\n\n\n\n<p><br>Key Components<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-Files\">Files<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Source<\/strong>:\u00a0<code>source\/DHCPMgrUtils\/dhcpmgr_recovery_handler.c<\/code><\/li>\n\n\n\n<li><strong>Header<\/strong>:\u00a0<code>source\/DHCPMgrUtils\/dhcpmgr_recovery_handler.h<\/code><\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-CoreFunctions\">Core Functions<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-DhcpMgr_Dhcp_Recovery_Start()\"><code>DhcpMgr_Dhcp_Recovery_Start()<\/code><\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Purpose<\/strong>: Initializes and starts the DHCP recovery system<\/li>\n\n\n\n<li><strong>Returns<\/strong>: 0 on success, negative error code on failure<\/li>\n\n\n\n<li><strong>Initialization<\/strong>: Sets up process monitoring and loads existing lease data<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-DHCPMgr_loadDhcpLeases()\"><code>DHCPMgr_loadDhcpLeases()<\/code><\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Purpose<\/strong>: Loads previously stored DHCP lease information during system startup<\/li>\n\n\n\n<li><strong>Scope<\/strong>: Processes both DHCPv4 and DHCPv6 lease files<\/li>\n\n\n\n<li><strong>Recovery<\/strong>: Restores TR-181 data model and client state<\/li>\n<\/ul>\n\n\n\n<p><br>Persistence System<br><br><strong>Storage Architecture<\/strong><\/p>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-DirectoryStructure\">Directory Structure<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/tmp\/Dhcp_manager\/\n\u251c\u2500\u2500 dhcpLease_1_v4    # DHCPv4 client instance 1\n\u251c\u2500\u2500 dhcpLease_1_v6    # DHCPv6 client instance 1\n\u251c\u2500\u2500 dhcpLease_2_v4    # DHCPv4 client instance 2\n\u2514\u2500\u2500 dhcpLease_2_v6    # DHCPv6 client instance 2\n<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-FileNamingConvention\">File Naming Convention<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Format<\/strong>:\u00a0<code>dhcpLease_{instanceNumber}_{version}<\/code><\/li>\n\n\n\n<li><strong>Instance Number<\/strong>: TR-181 client instance identifier<\/li>\n\n\n\n<li><strong>Version<\/strong>:\u00a0<code>v4<\/code>\u00a0for DHCPv4,\u00a0<code>v6<\/code>\u00a0for DHCPv6<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-DHCPv4LeaseStorage\">DHCPv4 Lease Storage<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-DHCPMgr_storeDhcpv4Lease(PCOSA_DML_DHCPC_FULLdata)\"><code>DHCPMgr_storeDhcpv4Lease(PCOSA_DML_DHCPC_FULL data)<\/code><\/h4>\n\n\n\n<p><strong>Purpose<\/strong>: Persists DHCPv4 lease information to filesystem<\/p>\n\n\n\n<p><strong>Storage Process<\/strong>:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Directory Creation<\/strong>: Ensure storage directory exists<\/li>\n\n\n\n<li><strong>File Creation<\/strong>: Create instance-specific lease file<\/li>\n\n\n\n<li><strong>Data Writing<\/strong>: Write complete client structure<\/li>\n\n\n\n<li><strong>Lease Storage<\/strong>: Append current lease information<\/li>\n\n\n\n<li><strong>Error Handling<\/strong>: Cleanup on write failures<\/li>\n<\/ol>\n\n\n\n<p><strong>Data Structure Storage<\/strong>:<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ Main client structure\nfwrite(data, sizeof(COSA_DML_DHCPC_FULL), 1, file);\n\n\/\/ Current lease information (if available)\nif (data->currentLease != NULL) {\n    fwrite(data->currentLease, sizeof(DHCPv4_PLUGIN_MSG), 1, file);\n}\n<\/pre>\n\n\n\n<p><strong>Stored Information<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Client Configuration<\/strong>: TR-181 client settings<\/li>\n\n\n\n<li><strong>Operational State<\/strong>: Current client status<\/li>\n\n\n\n<li><strong>Lease Data<\/strong>: Active lease information<\/li>\n\n\n\n<li><strong>Timing Information<\/strong>: Lease acquisition and expiration times<\/li>\n\n\n\n<li><strong>Network Configuration<\/strong>: IP address, gateway, DNS settings<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-DHCPv6LeaseStorage\">DHCPv6 Lease Storage<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-DHCPMgr_storeDhcpv6Lease(PCOSA_DML_DHCPCV6_FULLdata)\"><code>DHCPMgr_storeDhcpv6Lease(PCOSA_DML_DHCPCV6_FULL data)<\/code><\/h4>\n\n\n\n<p><strong>Purpose<\/strong>: Persists DHCPv6 lease information to filesystem<\/p>\n\n\n\n<p><strong>IPv6-Specific Storage<\/strong>:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Client Structure<\/strong>: Complete DHCPv6 client configuration<\/li>\n\n\n\n<li><strong>IANA Information<\/strong>: Non-temporary address data<\/li>\n\n\n\n<li><strong>IAPD Information<\/strong>: Prefix delegation data<\/li>\n\n\n\n<li><strong>Timing Parameters<\/strong>: T1, T2, preferred\/valid lifetimes<\/li>\n\n\n\n<li><strong>Server Information<\/strong>: DHCPv6 server details<\/li>\n<\/ol>\n\n\n\n<p><strong>Storage Format<\/strong>:<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ Main client structure\nfwrite(data, sizeof(COSA_DML_DHCPCV6_FULL), 1, file);\n\n\/\/ Current lease information (if available)\nif (data->currentLease != NULL) {\n    fwrite(data->currentLease, sizeof(DHCPv6_PLUGIN_MSG), 1, file);\n}\n<\/pre>\n\n\n\n<p><br>Recovery Process<\/p>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-SystemStartupRecovery\">System Startup Recovery<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-DHCPMgr_loadDhcpLeases().1\"><code>DHCPMgr_loadDhcpLeases()<\/code><\/h4>\n\n\n\n<p><strong>Recovery Flow<\/strong>:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Directory Scan<\/strong>: Check for existing lease files<\/li>\n\n\n\n<li><strong>File Validation<\/strong>: Verify file integrity and format<\/li>\n\n\n\n<li><strong>Data Loading<\/strong>: Read client and lease structures<\/li>\n\n\n\n<li><strong>State Restoration<\/strong>: Restore TR-181 data model<\/li>\n\n\n\n<li><strong>Client Restart<\/strong>: Restart DHCP clients with recovered state<\/li>\n<\/ol>\n\n\n\n<p><strong>Error Handling<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Corrupted Files<\/strong>: Skip corrupted lease files<\/li>\n\n\n\n<li><strong>Missing Data<\/strong>: Use default configurations<\/li>\n\n\n\n<li><strong>Permission Issues<\/strong>: Log errors and continue<\/li>\n\n\n\n<li><strong>Memory Allocation<\/strong>: Graceful degradation<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-DHCPv4Recovery\">DHCPv4 Recovery<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-load_v4dhcp_leases()\"><code>load_v4dhcp_leases()<\/code><\/h4>\n\n\n\n<p><strong>Recovery Steps<\/strong>:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Client Enumeration<\/strong>: Iterate through TR-181 DHCPv4 clients<\/li>\n\n\n\n<li><strong>File Location<\/strong>: Locate corresponding lease files<\/li>\n\n\n\n<li><strong>Data Validation<\/strong>: Verify lease data integrity<\/li>\n\n\n\n<li><strong>Structure Restoration<\/strong>: Rebuild client structures<\/li>\n\n\n\n<li><strong>TR-181 Update<\/strong>: Update data model with recovered information<\/li>\n<\/ol>\n\n\n\n<p><strong>Validation Checks<\/strong>:<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">\/\/ File size validation\nif (fileSize &lt; sizeof(COSA_DML_DHCPC_FULL)) {\n    DHCPMGR_LOG_ERROR(\"Invalid file size for client %lu\", instanceNum);\n    continue;\n}\n\n\/\/ Data integrity check\nif (fread(&amp;tempClient, sizeof(COSA_DML_DHCPC_FULL), 1, file) != 1) {\n    DHCPMGR_LOG_ERROR(\"Failed to read client data\");\n    continue;\n}\n<\/pre>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-DHCPv6Recovery\">DHCPv6 Recovery<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-load_v6dhcp_leases()\"><code>load_v6dhcp_leases()<\/code><\/h4>\n\n\n\n<p><strong>IPv6-Specific Recovery<\/strong>:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Client Iteration<\/strong>: Process all DHCPv6 client instances<\/li>\n\n\n\n<li><strong>File Processing<\/strong>: Load DHCPv6 lease files<\/li>\n\n\n\n<li><strong>IANA\/IAPD Recovery<\/strong>: Restore address and prefix information<\/li>\n\n\n\n<li><strong>Timer Restoration<\/strong>: Recover lease timing parameters<\/li>\n\n\n\n<li><strong>Configuration Apply<\/strong>: Apply recovered IPv6 configuration<\/li>\n<\/ol>\n\n\n\n<p><strong>IPv6 Validation<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Address Format<\/strong>: Validate IPv6 address formats<\/li>\n\n\n\n<li><strong>Prefix Length<\/strong>: Verify prefix length validity<\/li>\n\n\n\n<li><strong>Timer Values<\/strong>: Check timer consistency<\/li>\n\n\n\n<li><strong>Server Information<\/strong>: Validate server data<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-ProcessMonitoring\">Process Monitoring<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-PIDTrackingSystem\">PID Tracking System<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-ProcessRegistration\">Process Registration<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">int pids[MAX_PIDS];  \/\/ Array of monitored PIDs\nint pid_count = 0;   \/\/ Number of active PIDs\n<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-dhcp_pid_mon(void*args)\"><code>dhcp_pid_mon(void *args)<\/code><\/h4>\n\n\n\n<p><strong>Monitoring Process<\/strong>:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>PID Collection<\/strong>: Gather DHCP client process IDs<\/li>\n\n\n\n<li><strong>Health Monitoring<\/strong>: Continuously check process status<\/li>\n\n\n\n<li><strong>Failure Detection<\/strong>: Detect abnormal process termination<\/li>\n\n\n\n<li><strong>Recovery Trigger<\/strong>: Initiate recovery on process failure<\/li>\n\n\n\n<li><strong>Cleanup<\/strong>: Remove terminated processes from monitoring<\/li>\n<\/ol>\n\n\n\n<p><strong>Process Status Check<\/strong>:<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">for (int i = 0; i &lt; pid_count; i++) {\n    if (pids[i] > 0) {\n        int status;\n        pid_t result = waitpid(pids[i], &amp;status, WNOHANG);\n        \n        if (result == pids[i]) {\n            \/\/ Process terminated\n            DHCPMGR_LOG_INFO(\"Process %d terminated\", pids[i]);\n            processKilled(pids[i]);\n            pids[i] = -1;\n            active_pids--;\n        }\n    }\n}\n<\/pre>\n\n\n\n<p><strong>Process Recovery<\/strong><\/p>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-processKilled(pid_tpid)\"><code>processKilled(pid_t pid)<\/code><\/h4>\n\n\n\n<p><strong>Recovery Actions<\/strong>:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Process Identification<\/strong>: Determine which client process died<\/li>\n\n\n\n<li><strong>State Assessment<\/strong>: Evaluate impact of process termination<\/li>\n\n\n\n<li><strong>Cleanup<\/strong>: Clean up resources associated with dead process<\/li>\n\n\n\n<li><strong>Restart Decision<\/strong>: Determine if restart is appropriate<\/li>\n\n\n\n<li><strong>Recovery Execution<\/strong>: Restart client with recovered state<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-DataIntegrity\">Data Integrity<\/h2>\n\n\n\n<p><strong>File System Operations<\/strong><\/p>\n\n\n\n<p>Atomic Operations<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Temporary Files<\/strong>: Write to temporary files<\/li>\n\n\n\n<li><strong>Backup Strategy<\/strong>: Maintain backup copies during updates<\/li>\n\n\n\n<li><strong>Rollback Capability<\/strong>: Restore from backup on failure<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-Create_Dir_ifnEx(constchar*path)\"><code>Create_Dir_ifnEx(const char *path)<\/code><\/h4>\n\n\n\n<p><strong>Directory Management<\/strong>:<\/p>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">if (access(path, F_OK) == -1) {\n    if (mkdir(path, 0755) == -1) {\n        DHCPMGR_LOG_ERROR(\"Failed to create directory %s\", path);\n        return EXIT_FAIL;\n    }\n}\n<\/pre>\n\n\n\n<p><br>&nbsp;<strong>Data Validation<\/strong><\/p>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-FileIntegrityChecks\">File Integrity Checks<\/h4>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Size Validation<\/strong>: Verify file size matches expected structure size<\/li>\n\n\n\n<li><strong>Magic Numbers<\/strong>: Use file headers for format validation<\/li>\n\n\n\n<li><strong>Checksum Verification<\/strong>: Validate data integrity<\/li>\n\n\n\n<li><strong>Version Compatibility<\/strong>: Check file format versions<\/li>\n<\/ol>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-StructureValidation\">Structure Validation<\/h4>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Pointer Validation<\/strong>: Ensure pointers are valid or NULL<\/li>\n\n\n\n<li><strong>Range Checking<\/strong>: Validate numeric values within expected ranges<\/li>\n\n\n\n<li><strong>String Validation<\/strong>: Check string lengths and null termination<\/li>\n\n\n\n<li><strong>Consistency Checks<\/strong>: Verify related fields are consistent<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-ErrorHandlingandResilience\">Error Handling and Resilience<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-RecoveryStrategies\">Recovery Strategies<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-GracefulDegradation\">Graceful Degradation<\/h4>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Partial Recovery<\/strong>: Recover what data is available<\/li>\n\n\n\n<li><strong>Default Configuration<\/strong>: Use defaults for missing data<\/li>\n\n\n\n<li><strong>Continue Operation<\/strong>: Don&#8217;t let recovery failures stop service<\/li>\n\n\n\n<li><strong>Error Reporting<\/strong>: Log issues for later investigation<\/li>\n<\/ol>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-FailureScenarios\">Failure Scenarios<\/h4>\n\n\n\n<h5 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-CorruptedLeaseFiles\">Corrupted Lease Files<\/h5>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Detection<\/strong>: File size or format validation fails<\/li>\n\n\n\n<li><strong>Action<\/strong>: Skip corrupted file, use default configuration<\/li>\n\n\n\n<li><strong>Logging<\/strong>: Record corruption for investigation<\/li>\n<\/ul>\n\n\n\n<h5 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-MissingFiles\">Missing Files<\/h5>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Detection<\/strong>: Expected lease file not found<\/li>\n\n\n\n<li><strong>Action<\/strong>: Start with clean client configuration<\/li>\n\n\n\n<li><strong>Logging<\/strong>: Note missing file (may be normal)<\/li>\n<\/ul>\n\n\n\n<h5 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-PermissionIssues\">Permission Issues<\/h5>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Detection<\/strong>: File system access denied<\/li>\n\n\n\n<li><strong>Action<\/strong>: Continue without persistence<\/li>\n\n\n\n<li><strong>Logging<\/strong>: Record permission issues<\/li>\n<\/ul>\n\n\n\n<h5 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-MemoryAllocationFailures\">Memory Allocation Failures<\/h5>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Detection<\/strong>: malloc() returns NULL<\/li>\n\n\n\n<li><strong>Action<\/strong>: Skip affected client, continue with others<\/li>\n\n\n\n<li><strong>Logging<\/strong>: Record memory pressure<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-CleanupandResourceManagement\">Cleanup and Resource Management<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-remove_dhcp_lease_file(intinstanceNumber,intdhcpVersion)\"><code>remove_dhcp_lease_file(int instanceNumber, int dhcpVersion)<\/code><\/h4>\n\n\n\n<p><strong>Purpose<\/strong>: Removes lease files when clients are deleted<\/p>\n\n\n\n<p><strong>Parameters<\/strong>:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>instanceNumber<\/strong>: TR-181 client instance number<\/li>\n\n\n\n<li><strong>dhcpVersion<\/strong>: DHCP_v4 (0) or DHCP_v6 (1)<\/li>\n<\/ul>\n\n\n\n<p><strong>Cleanup Process<\/strong>:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>File Path Construction<\/strong>: Build path to lease file<\/li>\n\n\n\n<li><strong>Existence Check<\/strong>: Verify file exists before deletion<\/li>\n\n\n\n<li><strong>File Removal<\/strong>: Delete lease file from filesystem<\/li>\n\n\n\n<li><strong>Error Handling<\/strong>: Log but don&#8217;t fail on deletion errors<\/li>\n<\/ol>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-ConfigurationandCustomization\">Configuration and Customization<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-StorageConfiguration\">Storage Configuration<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-DirectorySettings\">Directory Settings<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">#define TMP_DIR_PATH \"\/tmp\/Dhcp_manager\"\n<\/pre>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-FilePermissions\">File Permissions<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Directory<\/strong>: 0755 (readable\/executable by all, writable by owner)<\/li>\n\n\n\n<li><strong>Files<\/strong>: Default permissions (typically 0644)<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-SizeLimits\">Size Limits<\/h4>\n\n\n\n<pre class=\"EnlighterJSRAW\" data-enlighter-language=\"generic\" data-enlighter-theme=\"\" data-enlighter-highlight=\"\" data-enlighter-linenumbers=\"\" data-enlighter-lineoffset=\"\" data-enlighter-title=\"\" data-enlighter-group=\"\">#define MAX_PIDS 20  \/\/ Maximum monitored processes\n<\/pre>\n\n\n\n<p><br><strong>Recovery Behavior<\/strong><\/p>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-StartupBehavior\">Startup Behavior<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Auto-Recovery<\/strong>: Automatically load existing lease data<\/li>\n\n\n\n<li><strong>Validation<\/strong>: Verify data integrity before use<\/li>\n\n\n\n<li><strong>Fallback<\/strong>: Use defaults if recovery fails<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-RuntimeBehavior\">Runtime Behavior<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Continuous Monitoring<\/strong>: Monitor process health<\/li>\n\n\n\n<li><strong>Immediate Storage<\/strong>: Store lease changes immediately<\/li>\n\n\n\n<li><strong>Periodic Cleanup<\/strong>: Remove stale lease files<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-DebuggingandTroubleshooting\">Debugging and Troubleshooting<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-DebugFeatures\">Debug Features<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-ComprehensiveLogging\">Comprehensive Logging<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Recovery Events<\/strong>: Log all recovery operations<\/li>\n\n\n\n<li><strong>File Operations<\/strong>: Log file system operations<\/li>\n\n\n\n<li><strong>Process Events<\/strong>: Log process monitoring events<\/li>\n\n\n\n<li><strong>Error Conditions<\/strong>: Detailed error reporting<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-CommonIssues\">Common Issues<\/h4>\n\n\n\n<h5 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-RecoveryFailures\">Recovery Failures<\/h5>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Corrupted Files<\/strong>: Check file integrity and format<\/li>\n\n\n\n<li><strong>Permission Denied<\/strong>: Verify file system permissions<\/li>\n\n\n\n<li><strong>Memory Issues<\/strong>: Check available memory<\/li>\n\n\n\n<li><strong>Process Issues<\/strong>: Verify process monitoring<\/li>\n<\/ol>\n\n\n\n<h5 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-PerformanceIssues\">Performance Issues<\/h5>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Slow Recovery<\/strong>: Check file system performance<\/li>\n\n\n\n<li><strong>High CPU Usage<\/strong>: Monitor process monitoring overhead<\/li>\n\n\n\n<li><strong>Memory Leaks<\/strong>: Check resource cleanup<\/li>\n\n\n\n<li><strong>File System Full<\/strong>: Monitor disk space usage<\/li>\n<\/ol>\n\n\n\n<h3 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-DiagnosticTools\">Diagnostic Tools<\/h3>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-FileInspection\">File Inspection<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>File Size Check<\/strong>: Verify lease file sizes<\/li>\n\n\n\n<li><strong>Content Validation<\/strong>: Manually inspect file contents<\/li>\n\n\n\n<li><strong>Timestamp Analysis<\/strong>: Check file modification times<\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\" id=\"DHCPRecoveryHandler-ProcessMonitoring.1\">Process Monitoring<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>PID Tracking<\/strong>: Monitor active process IDs<\/li>\n\n\n\n<li><strong>Status Checking<\/strong>: Verify process health<\/li>\n\n\n\n<li><strong>Resource Usage<\/strong>: Monitor process resource consumption<\/li>\n<\/ul>\n\n\n\n<p><a href=\"https:\/\/wiki.rdkcentral.com\/spaces\/DOC\/pages\/466452795\/DHCP+Recovery+Handler\"><\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>The DHCP Recovery Handler provides persistence and recovery functionality for the DHCP Client Manager. It [&hellip;]<\/p>\n","protected":false},"author":659,"featured_media":0,"parent":12785,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_bbp_topic_count":0,"_bbp_reply_count":0,"_bbp_total_topic_count":0,"_bbp_total_reply_count":0,"_bbp_voice_count":0,"_bbp_anonymous_reply_count":0,"_bbp_topic_count_hidden":0,"_bbp_reply_count_hidden":0,"_bbp_forum_subforum_count":0,"footnotes":""},"class_list":["post-12814","page","type-page","status-publish","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v24.9 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>DHCP Recovery Handler - RDK Documentation Portal | Documentation<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/developer.rdkcentral.com\/documentation\/documentation\/rdk_broadband_documentation\/components\/dhcp-client-manager\/dhcp-recovery-handler\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"DHCP Recovery Handler - RDK Documentation Portal | Documentation\" \/>\n<meta property=\"og:description\" content=\"The DHCP Recovery Handler provides persistence and recovery functionality for the DHCP Client Manager. 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