v1.2.11 - Early duplicate check before secp256k1 signature verification — skip crypto for events already in DB

src/main.c

@@ -881,6 +881,22 @@ int store_event(cJSON* event) {
     return 0;
 }
 
+// Fast duplicate check: returns 1 if event ID already exists in DB, 0 if not.
+// Uses the primary key index — single B-tree lookup, ~10μs.
+// Call this BEFORE signature verification to skip expensive crypto on duplicates.
+int event_id_exists_in_db(const char* event_id) {
+    if (!g_db || !event_id || strlen(event_id) != 64) return 0;
+
+    sqlite3_stmt* stmt;
+    const char* sql = "SELECT 1 FROM events WHERE id=? LIMIT 1";
+    if (sqlite3_prepare_v2(g_db, sql, -1, &stmt, NULL) != SQLITE_OK) return 0;
+
+    sqlite3_bind_text(stmt, 1, event_id, 64, SQLITE_STATIC);
+    int exists = (sqlite3_step(stmt) == SQLITE_ROW) ? 1 : 0;
+    sqlite3_finalize(stmt);
+    return exists;
+}
+
 // Populate event_tags from existing events (run once at startup)
 int populate_event_tags_from_existing(void) {
     if (!g_db) return -1;
@@ -1552,21 +1568,24 @@ int handle_req_message(const char* sub_id, cJSON* filters, struct lws *wsi, stru
                 }
             }
             
-            // Build EVENT message using string concatenation (much faster than cJSON operations)
+            // Build EVENT message using zero-copy path: allocate with LWS_PRE prefix,
+            // write directly, transfer ownership to queue — no memcpy.
             // Format: ["EVENT","<sub_id>",<event_json>]
             size_t sub_id_len = strlen(sub_id);
             size_t event_json_len = strlen(event_json_str);
-            size_t msg_len = 10 + sub_id_len + 3 + event_json_len + 1; // ["EVENT",""] + sub_id + "," + event_json + ]
-            
-            char* msg_str = malloc(msg_len + 1);
-            if (msg_str) {
-                snprintf(msg_str, msg_len + 1, "[\"EVENT\",\"%s\",%s]", sub_id, event_json_str);
-                
-                // Use proper message queue system instead of direct lws_write
-                if (queue_message(wsi, pss, msg_str, strlen(msg_str), LWS_WRITE_TEXT) != 0) {
+            size_t msg_len = 10 + sub_id_len + 3 + event_json_len + 1;
+
+            unsigned char* buf = malloc(LWS_PRE + msg_len + 1);
+            if (buf) {
+                char* msg_ptr = (char*)(buf + LWS_PRE);
+                snprintf(msg_ptr, msg_len + 1, "[\"EVENT\",\"%s\",%s]", sub_id, event_json_str);
+                size_t actual_len = strlen(msg_ptr);
+
+                // queue_message_take_ownership takes buf ownership — no memcpy, no free needed here
+                if (queue_message_take_ownership(wsi, pss, buf, actual_len, LWS_WRITE_TEXT) != 0) {
                     DEBUG_ERROR("Failed to queue EVENT message for sub=%s", sub_id);
+                    // buf already freed by queue_message_take_ownership on failure
                 }
-                free(msg_str);
             }
 
             cJSON_Delete(event);

src/main.h

@@ -13,8 +13,8 @@
 // Using CRELAY_ prefix to avoid conflicts with nostr_core_lib VERSION macros
 #define CRELAY_VERSION_MAJOR 1
 #define CRELAY_VERSION_MINOR 2
-#define CRELAY_VERSION_PATCH 9
-#define CRELAY_VERSION "v1.2.9"
+#define CRELAY_VERSION_PATCH 11
+#define CRELAY_VERSION "v1.2.11"
 
 // Relay metadata (authoritative source for NIP-11 information)
 #define RELAY_NAME "C-Relay"

src/subscriptions.c

@@ -876,7 +876,6 @@ int broadcast_event_to_subscriptions(cJSON* event) {
         // Serialize event once per subscription using pre-serialized event_json if available,
         // otherwise fall back to cJSON serialization.
         // Format: ["EVENT","<sub_id>",<event_json>]
-        cJSON* event_id_obj = cJSON_GetObjectItemCaseSensitive(event, "id");
         const char* event_json_str = NULL;
         char* event_json_allocated = NULL;
 
@@ -895,16 +894,19 @@ int broadcast_event_to_subscriptions(cJSON* event) {
             size_t event_json_len = strlen(event_json_str);
             // ["EVENT","<sub_id>",<event_json>]
             size_t msg_len = 10 + sub_id_len + 3 + event_json_len + 1;
-            char* msg_str = malloc(msg_len + 1);
-            if (msg_str) {
-                snprintf(msg_str, msg_len + 1, "[\"EVENT\",\"%s\",%s]", current_temp->id, event_json_str);
-                size_t actual_len = strlen(msg_str);
+
+            // Zero-copy: allocate with LWS_PRE prefix, write directly, transfer ownership to queue
+            unsigned char* buf = malloc(LWS_PRE + msg_len + 1);
+            if (buf) {
+                char* msg_ptr = (char*)(buf + LWS_PRE);
+                snprintf(msg_ptr, msg_len + 1, "[\"EVENT\",\"%s\",%s]", current_temp->id, event_json_str);
+                size_t actual_len = strlen(msg_ptr);
 
                 DEBUG_TRACE("WS_FRAME_SEND: type=EVENT sub=%s len=%zu", current_temp->id, actual_len);
 
-                // Queue message for proper libwebsockets pattern
                 struct per_session_data* pss = (struct per_session_data*)lws_wsi_user(current_temp->wsi);
-                if (queue_message(current_temp->wsi, pss, msg_str, actual_len, LWS_WRITE_TEXT) == 0) {
+                // queue_message_take_ownership takes buf ownership — no memcpy, no free needed here
+                if (queue_message_take_ownership(current_temp->wsi, pss, buf, actual_len, LWS_WRITE_TEXT) == 0) {
                     broadcasts++;
 
                     // Update events sent counter for this subscription
@@ -922,8 +924,8 @@ int broadcast_event_to_subscriptions(cJSON* event) {
                     pthread_mutex_unlock(&g_subscription_manager.subscriptions_lock);
                 } else {
                     DEBUG_ERROR("Failed to queue EVENT message for sub=%s", current_temp->id);
+                    // buf already freed by queue_message_take_ownership on failure
                 }
-                free(msg_str);
             }
         }
         if (event_json_allocated) {

src/websockets.c

@@ -64,6 +64,7 @@ int remove_subscription_from_manager(const char* sub_id, struct lws* wsi);
 // Forward declarations for event handling
 int handle_event_message(cJSON* event, char* error_message, size_t error_size);
 int nostr_validate_unified_request(const char* json_string, size_t json_length);
+int event_id_exists_in_db(const char* event_id);
 
 // Forward declarations for admin event processing
 int process_admin_event_in_config(cJSON* event, char* error_message, size_t error_size, struct lws* wsi);
@@ -194,6 +195,66 @@ int queue_message(struct lws* wsi, struct per_session_data* pss, const char* mes
     return 0;
 }
 
+/**
+ * Zero-copy variant of queue_message. The caller allocates a buffer of
+ * (LWS_PRE + length) bytes, writes the message at (buf + LWS_PRE), then
+ * passes ownership to the queue. The queue will free buf when done.
+ * No memcpy is performed — eliminates one copy per queued message.
+ *
+ * @param wsi WebSocket instance
+ * @param pss Per-session data containing message queue
+ * @param buf Pre-allocated buffer of size (LWS_PRE + length); ownership transferred
+ * @param length Length of message (NOT including LWS_PRE)
+ * @param type LWS_WRITE_* type
+ * @return 0 on success, -1 on error (buf is freed on error)
+ */
+int queue_message_take_ownership(struct lws* wsi, struct per_session_data* pss, unsigned char* buf, size_t length, enum lws_write_protocol type) {
+    if (!wsi || !pss || !buf || length == 0) {
+        DEBUG_ERROR("queue_message_take_ownership: invalid parameters");
+        free(buf);
+        return -1;
+    }
+
+    // Drop message if queue is full
+    if (pss->message_queue_count >= MAX_MESSAGE_QUEUE_SIZE) {
+        DEBUG_WARN("queue_message_take_ownership: queue full (%d), dropping message",
+                   pss->message_queue_count);
+        free(buf);
+        return -1;
+    }
+
+    struct message_queue_node* node = malloc(sizeof(struct message_queue_node));
+    if (!node) {
+        DEBUG_ERROR("queue_message_take_ownership: failed to allocate queue node");
+        free(buf);
+        return -1;
+    }
+
+    node->data = buf;       // buf already has LWS_PRE prefix — no copy needed
+    node->length = length;
+    node->type = type;
+    node->next = NULL;
+
+    pthread_mutex_lock(&pss->session_lock);
+    if (!pss->message_queue_head) {
+        pss->message_queue_head = node;
+        pss->message_queue_tail = node;
+    } else {
+        pss->message_queue_tail->next = node;
+        pss->message_queue_tail = node;
+    }
+    pss->message_queue_count++;
+    pthread_mutex_unlock(&pss->session_lock);
+
+    if (!pss->writeable_requested) {
+        pss->writeable_requested = 1;
+        lws_callback_on_writable(wsi);
+    }
+
+    DEBUG_TRACE("Queued message (zero-copy): len=%zu, queue_count=%d", length, pss->message_queue_count);
+    return 0;
+}
+
 /**
  * Process message queue when the socket becomes writeable.
  * This function is called from LWS_CALLBACK_SERVER_WRITEABLE.
@@ -609,6 +670,27 @@ static int nostr_relay_callback(struct lws *wsi, enum lws_callback_reasons reaso
                                             return 0;
                                         }
 
+                                        // Early duplicate check: skip expensive crypto for events already in DB.
+                                        // The event id is a 64-char hex string — look it up via primary key index (~10μs).
+                                        // This must happen AFTER we have the id string but BEFORE signature verification.
+                                        cJSON* id_obj_dup = cJSON_GetObjectItemCaseSensitive(event, "id");
+                                        if (id_obj_dup && cJSON_IsString(id_obj_dup)) {
+                                            const char* event_id_str = cJSON_GetStringValue(id_obj_dup);
+                                            if (event_id_str && event_id_exists_in_db(event_id_str)) {
+                                                // Already have this event — send OK true and skip crypto
+                                                DEBUG_TRACE("Duplicate event %s — skipping signature verification", event_id_str);
+                                                char ok_msg[128];
+                                                snprintf(ok_msg, sizeof(ok_msg),
+                                                    "[\"OK\",\"%s\",true,\"duplicate: already have this event\"]",
+                                                    event_id_str);
+                                                size_t ok_len = strlen(ok_msg);
+                                                queue_message(wsi, pss, ok_msg, ok_len, LWS_WRITE_TEXT);
+                                                free(event_json_str);
+                                                cJSON_Delete(json);
+                                                return 0;
+                                            }
+                                        }
+
                                         // Call unified validator with JSON string
                                         size_t event_json_len = strlen(event_json_str);
                                         int validation_result = nostr_validate_unified_request(event_json_str, event_json_len);
@@ -1344,6 +1426,25 @@ static int nostr_relay_callback(struct lws *wsi, enum lws_callback_reasons reaso
                                         return 0;
                                     }
                                     
+                                    // Early duplicate check: skip expensive crypto for events already in DB.
+                                    cJSON* id_obj_dup2 = cJSON_GetObjectItemCaseSensitive(event, "id");
+                                    if (id_obj_dup2 && cJSON_IsString(id_obj_dup2)) {
+                                        const char* event_id_str2 = cJSON_GetStringValue(id_obj_dup2);
+                                        if (event_id_str2 && event_id_exists_in_db(event_id_str2)) {
+                                            DEBUG_TRACE("Duplicate event %s — skipping signature verification", event_id_str2);
+                                            char ok_msg2[128];
+                                            snprintf(ok_msg2, sizeof(ok_msg2),
+                                                "[\"OK\",\"%s\",true,\"duplicate: already have this event\"]",
+                                                event_id_str2);
+                                            size_t ok_len2 = strlen(ok_msg2);
+                                            queue_message(wsi, pss, ok_msg2, ok_len2, LWS_WRITE_TEXT);
+                                            free(event_json_str);
+                                            cJSON_Delete(json);
+                                            free(message);
+                                            return 0;
+                                        }
+                                    }
+
                                     // Call unified validator with JSON string
                                     size_t event_json_len = strlen(event_json_str);
                                     int validation_result = nostr_validate_unified_request(event_json_str, event_json_len);

src/websockets.h

@@ -107,6 +107,10 @@ int start_websocket_relay(int port_override, int strict_port);
 int queue_message(struct lws* wsi, struct per_session_data* pss, const char* message, size_t length, enum lws_write_protocol type);
 int process_message_queue(struct lws* wsi, struct per_session_data* pss);
 
+// Zero-copy variant: caller allocates (LWS_PRE + length) bytes, writes message at buf+LWS_PRE,
+// then passes ownership to the queue. The queue will free buf when done. No memcpy performed.
+int queue_message_take_ownership(struct lws* wsi, struct per_session_data* pss, unsigned char* buf, size_t length, enum lws_write_protocol type);
+
 // Auth rules checking function from request_validator.c
 int check_database_auth_rules(const char *pubkey, const char *operation, const char *resource_hash);