// Application-specific message routing
struct diameter_application {
 uint32_t application_id;
 char *application_name;
 int (*message_handler)(struct msg *message);
 int (*peer_connect_handler)(struct peer *peer);
}; static struct diameter_application supported_apps[] = {
 {
 .application_id = DIAMETER_APP_S6A,
 .application_name = "3GPP S6a",
 .message_handler = handle_s6a_message,
 .peer_connect_handler = s6a_peer_connect
 },
 {
 .application_id = DIAMETER_APP_CX,
 .application_name = "3GPP Cx", 
 .message_handler = handle_cx_message,
 .peer_connect_handler = cx_peer_connect
 }
};

# _Transforms.py - Advanced message transformation
class DiameterMessageTransformer: def __init__(self): self.transformation_rules = self.load_transformation_rules() def transform_message(self, message, peer_info):
 """Transform Diameter message based on destination peer requirements""" # Extract message details msg_type = self.get_message_type(message) destination_peer = peer_info.get('peer_name') # Apply peer-specific transformations if destination_peer.startswith('comfone'): return self.apply_comfone_transformations(message, msg_type) elif destination_peer.startswith('sparkle'): return self.apply_sparkle_transformations(message, msg_type) elif destination_peer.startswith('oxio'): return self.apply_oxio_transformations(message, msg_type) return message def apply_comfone_transformations(self, message, msg_type):
 """Comfone-specific message transformations""" if msg_type == 'AIR': # Authentication Information Request # Comfone requires specific AVP ordering message = self.reorder_avps(message, COMFONE_AVP_ORDER) # Add Comfone-specific routing AVPs message = self.add_routing_avp(message, avp_code=AVP_DESTINATION_REALM, avp_value="comfone.partner.net") elif msg_type == 'ULR': # Update Location Request  # Transform IMSI format for Comfone compatibility imsi = self.extract_avp(message, AVP_USER_NAME) transformed_imsi = self.transform_imsi_format(imsi, 'comfone') message = self.update_avp(message, AVP_USER_NAME, transformed_imsi) return message def apply_sparkle_transformations(self, message, msg_type):
 """Sparkle-specific message transformations""" if msg_type == 'CLR': # Cancel Location Request # Sparkle requires additional routing information visited_plmn = self.extract_avp(message, AVP_VISITED_PLMN_ID) routing_realm = self.calculate_sparkle_realm(visited_plmn) message = self.add_routing_avp(message, avp_code=AVP_DESTINATION_REALM, avp_value=routing_realm) # Handle Sparkle's custom AVP extensions message = self.add_vendor_specific_avps(message, VENDOR_ID_SPARKLE) return message

// High-performance message processing architecture
struct message_processor {
 struct fd_queue *incoming_queue;
 struct fd_queue *outgoing_queue;
 pthread_t *worker_threads;
 int num_workers;
 struct statistics stats;
}; static void* message_worker_thread(void *arg) {
 struct message_processor *processor = (struct message_processor*)arg;
 struct msg *message;  while (1) {
 // Get message from queue (blocking)
 fd_queue_get(processor->incoming_queue, (void**)&message);  // Process message with timing
 struct timespec start_time, end_time;
 clock_gettime(CLOCK_MONOTONIC, &start_time);  int result = process_diameter_message(message);  clock_gettime(CLOCK_MONOTONIC, &end_time);  // Update performance statistics
 long processing_time = timespec_diff(&start_time, &end_time);
 update_processing_stats(&processor->stats, processing_time, result);  // Send processed message
 if (result == 0) {
 fd_queue_put(processor->outgoing_queue, message);
 } else {
 // Handle processing error
 handle_message_error(message, result);
 }
 }  return NULL;
} static int process_diameter_message(struct msg *message) {
 // Extract command code and application ID
 uint32_t cmd_code = get_command_code(message);
 uint32_t app_id = get_application_id(message);  // Route to appropriate application handler
 switch (app_id) {
 case DIAMETER_APP_S6A:
 return process_s6a_message(message, cmd_code);
 case DIAMETER_APP_CX:
 return process_cx_message(message, cmd_code);
 default:
 // Unknown application
 return DIAMETER_UNKNOWN_APPLICATION;
 }
}

class DiameterRoutingEngine: def __init__(self): self.peer_monitor = PeerMonitor() self.load_balancer = LoadBalancer() self.geographic_router = GeographicRouter() def route_message(self, message):
 """Intelligent message routing based on multiple factors""" # Extract routing information from message destination_realm = self.extract_destination_realm(message) user_name = self.extract_user_name(message) message_type = self.get_message_type(message) # Get available peers for destination realm available_peers = self.peer_monitor.get_available_peers(destination_realm) if not available_peers: return self.handle_no_peers_available(message) # Apply routing strategy based on message type if message_type in ['AIR', 'ULR']: # Real-time messages selected_peer = self.select_low_latency_peer(available_peers) elif message_type in ['CLR', 'IDR']: # Bulk messages  selected_peer = self.load_balancer.select_peer(available_peers) else: # Geographic routing for location-sensitive messages mcc_mnc = self.extract_mcc_mnc(user_name) selected_peer = self.geographic_router.select_peer( available_peers, mcc_mnc) return selected_peer def select_low_latency_peer(self, peers):
 """Select peer with lowest average response time""" best_peer = None lowest_latency = float('inf') for peer in peers: avg_latency = self.peer_monitor.get_average_latency(peer) if avg_latency < lowest_latency: lowest_latency = avg_latency best_peer = peer return best_peer class PeerMonitor: def __init__(self): self.peer_stats = {} self.health_checker = HealthChecker() def get_available_peers(self, realm):
 """Get list of healthy peers for given realm""" realm_peers = self.get_realm_peers(realm) available_peers = [] for peer in realm_peers: if self.is_peer_healthy(peer): available_peers.append(peer) return available_peers def is_peer_healthy(self, peer):
 """Check if peer is healthy and available""" return (self.peer_stats[peer]['connection_state'] == 'OPEN' and self.peer_stats[peer]['error_rate'] < 0.01 and # <1% error rate self.peer_stats[peer]['response_time'] < 1.0) # <1s response

class DiameterMessageValidator: def __init__(self): self.avp_definitions = self.load_avp_definitions() self.command_definitions = self.load_command_definitions() def validate_message(self, message):
 """Comprehensive message validation""" validation_errors = [] # Basic format validation if not self.validate_message_format(message): validation_errors.append("Invalid message format") # Command code validation cmd_code = self.get_command_code(message) if cmd_code not in self.command_definitions: validation_errors.append(f"Unknown command code: {cmd_code}") # AVP validation avp_errors = self.validate_avps(message) validation_errors.extend(avp_errors) # Application-specific validation app_id = self.get_application_id(message) app_errors = self.validate_application_specific(message, app_id) validation_errors.extend(app_errors) return validation_errors def validate_avps(self, message):
 """Validate all AVPs in message""" errors = [] avps = self.extract_all_avps(message) for avp in avps: avp_code = avp.get_code() avp_value = avp.get_value() # Check if AVP is defined if avp_code not in self.avp_definitions: errors.append(f"Unknown AVP code: {avp_code}") continue # Validate AVP value format expected_type = self.avp_definitions[avp_code]['type'] if not self.validate_avp_type(avp_value, expected_type): errors.append(f"Invalid value for AVP {avp_code}: {avp_value}") return errors

class DiameterPerformanceMonitor: def __init__(self): self.metrics_collector = MetricsCollector() self.alert_manager = AlertManager() def record_message_processing(self, message, processing_time, result):
 """Record message processing metrics""" # Extract message metadata cmd_code = self.get_command_code(message) app_id = self.get_application_id(message) peer = self.get_origin_host(message) # Record basic metrics self.metrics_collector.increment_counter( 'diameter_messages_total', labels={ 'command': cmd_code, 'application': app_id, 'peer': peer, 'result': 'success' if result == 0 else 'error' } ) # Record processing time self.metrics_collector.record_histogram( 'diameter_processing_time_seconds', processing_time, labels={'command': cmd_code, 'application': app_id} ) # Check for SLA violations if processing_time > 0.5: # 500ms SLA self.alert_manager.trigger_alert( 'diameter_processing_slow', f'Message processing exceeded SLA: {processing_time:.2f}s', severity='warning', labels={'peer': peer, 'command': cmd_code} ) def generate_performance_report(self, time_range):
 """Generate comprehensive performance report""" metrics = self.metrics_collector.query_range( time_range.start, time_range.end ) report = { 'summary': { 'total_messages': metrics['diameter_messages_total'].sum(), 'success_rate': self.calculate_success_rate(metrics), 'average_latency': metrics['diameter_processing_time_seconds'].mean(), 'p95_latency': metrics['diameter_processing_time_seconds'].quantile(0.95), 'peak_throughput': metrics['diameter_messages_total'].max_rate() }, 'per_application': self.analyze_per_application(metrics), 'per_peer': self.analyze_per_peer(metrics), 'error_analysis': self.analyze_errors(metrics) } return report

// High availability with automatic failover
struct ha_peer_group {
 char *group_name;
 struct peer_info *primary_peer;
 struct peer_info **backup_peers;
 int num_backup_peers;
 int current_active_peer;
 time_t last_failover;
 int failover_count;
}; static int handle_peer_failure(struct peer_info *failed_peer) {
 struct ha_peer_group *group = find_peer_group(failed_peer);  if (!group) {
 LOG_ERROR("Failed peer not in any HA group: %s", failed_peer->name);
 return -1;
 }  // Find next available backup peer
 struct peer_info *backup_peer = select_backup_peer(group);  if (!backup_peer) {
 LOG_CRITICAL("No backup peers available for group: %s", group->group_name);
 trigger_critical_alert(group);
 return -1;
 }  // Perform failover
 LOG_INFO("Failing over from %s to %s", failed_peer->name, backup_peer->name);  // Update routing tables
 update_routing_table(failed_peer, backup_peer);  // Redirect pending messages
 redirect_pending_messages(failed_peer, backup_peer);  // Update group state
 group->current_active_peer = get_peer_index(group, backup_peer);
 group->last_failover = time(NULL);
 group->failover_count++;  // Send notification
 send_failover_notification(group, failed_peer, backup_peer);  return 0;
} static void monitor_peer_health(void) {
 while (1) {
 struct peer_info **all_peers = get_all_peers();  for (int i = 0; all_peers[i]; i++) {
 struct peer_info *peer = all_peers[i];  // Check peer connectivity
 if (!is_peer_connected(peer)) {
 handle_peer_failure(peer);
 continue;
 }  // Check peer performance
 double avg_response_time = get_peer_avg_response_time(peer);
 if (avg_response_time > MAX_RESPONSE_TIME) {
 LOG_WARNING("Peer %s response time degraded: %.2fms", 
 peer->name, avg_response_time);  if (avg_response_time > FAILOVER_RESPONSE_TIME) {
 handle_peer_failure(peer);
 }
 }  // Check error rate
 double error_rate = get_peer_error_rate(peer);
 if (error_rate > MAX_ERROR_RATE) {
 LOG_WARNING("Peer %s error rate high: %.2f%%", 
 peer->name, error_rate * 100);  if (error_rate > FAILOVER_ERROR_RATE) {
 handle_peer_failure(peer);
 }
 }
 }  // Sleep before next health check
 usleep(HEALTH_CHECK_INTERVAL * 1000); // Convert ms to microseconds
 }
}

# Production FreeDiameter configuration template
LoadExtension = "dict_s6a.fdx";
LoadExtension = "dict_cx.fdx";
LoadExtension = "rt_pyform.fdx"; ListenOn = "{{ LISTEN_ADDRESS }}";
Port = {{ DIAMETER_PORT }};
SecPort = {{ DIAMETER_SEC_PORT }}; {{#if TLS_ENABLED}}
TLS_Cred = "{{ TLS_CERT_PATH }}", "{{ TLS_KEY_PATH }}";
TLS_CA = "{{ TLS_CA_PATH }}";
{{/if}} {{#each PEERS}}
ConnectPeer = "{{ name }}" {
 ConnectTo = "{{ address }}";
 {{#if ../TLS_ENABLED}}
 TLS_Prio = "SECURE128:+SECURE192:-VERS-ALL:+VERS-TLS1.2";
 {{else}}
 No_TLS;
 {{/if}}
 {{#if weight}}
 Weight = {{ weight }};
 {{/if}}
};
{{/each}} LoadExtension = "rt_pyform.fdx" : "{{ PYFORM_CONFIG_PATH }}";

# Prometheus monitoring configuration
global:
 scrape_interval: 15s
 evaluation_interval: 15s rule_files:
 - "diameter_alerts.yml" scrape_configs:
 - job_name: 'diameter-dra'
 static_configs:
 - targets: ['dra-instance:9090']
 metrics_path: /metrics
 scrape_interval: 5s alerting:
 alertmanagers:
 - static_configs:
 - targets: ['alertmanager:9093'] # Alert rules
groups:
- name: diameter_sla_alerts
 rules:
 - alert: DiameterHighLatency
 expr: diameter_processing_time_seconds{quantile="0.95"} > 0.1
 for: 2m
 labels:
 severity: warning
 annotations:
 summary: "Diameter processing latency high"
 description: "95th percentile processing time is {{ $value }}s"  - alert: DiameterPeerDown
 expr: diameter_peer_connected == 0
 for: 30s
 labels:
 severity: critical
 annotations:
 summary: "Diameter peer {{ $labels.peer }} is down"