Add ping/pong message handling to wsssh C implementation

- Implement explicit ping/pong frame parsing and response in wsssh.c
- Add send_pong_frame function to handle WebSocket ping frames
- Maintain WebSocket protocol compliance for connection keep-alive
- Python implementations handle ping/pong automatically via websockets library

wssshtools/wsssh.c

@@ -58,6 +58,49 @@ tunnel_t *active_tunnel = NULL;
 pthread_mutex_t tunnel_mutex;
 
 int send_websocket_frame(SSL *ssl, const char *data);
+int send_pong_frame(SSL *ssl, const char *ping_payload, int payload_len);
+
+int send_pong_frame(SSL *ssl, const char *ping_payload, int payload_len) {
+    char frame[BUFFER_SIZE];
+    frame[0] = 0x8A; // FIN + pong opcode
+    int header_len = 2;
+
+    if (payload_len <= 125) {
+        frame[1] = 0x80 | payload_len; // MASK + length
+    } else if (payload_len <= 65535) {
+        frame[1] = 0x80 | 126; // MASK + extended length
+        frame[2] = (payload_len >> 8) & 0xFF;
+        frame[3] = payload_len & 0xFF;
+        header_len = 4;
+    } else {
+        frame[1] = 0x80 | 127; // MASK + extended length
+        frame[2] = 0;
+        frame[3] = 0;
+        frame[4] = 0;
+        frame[5] = 0;
+        frame[6] = (payload_len >> 24) & 0xFF;
+        frame[7] = (payload_len >> 16) & 0xFF;
+        frame[8] = (payload_len >> 8) & 0xFF;
+        frame[9] = payload_len & 0xFF;
+        header_len = 10;
+    }
+
+    // Add mask key
+    char mask_key[4];
+    for (int i = 0; i < 4; i++) {
+        mask_key[i] = rand() % 256;
+        frame[header_len + i] = mask_key[i];
+    }
+    header_len += 4;
+
+    // Mask payload
+    for (int i = 0; i < payload_len; i++) {
+        frame[header_len + i] = ping_payload[i] ^ mask_key[i % 4];
+    }
+
+    int frame_len = header_len + payload_len;
+    return SSL_write(ssl, frame, frame_len) > 0;
+}
 
 void print_trans_flag(void) {
     // Transgender pride flag colors using ANSI escape codes
@@ -1090,8 +1133,11 @@ int main(int argc, char *argv[]) {
                 break;
             }
 
-            // Check if it's a close frame
-            if (bytes_read >= 2 && (buffer[0] & 0x8F) == 0x88) {
+            // Check frame type
+            unsigned char frame_type = buffer[0] & 0x8F;
+    
+            // Handle close frame
+            if (frame_type == 0x88) {
                 if (config.debug) {
                     printf("[DEBUG] Received close frame from server\n");
                     fflush(stdout);
@@ -1099,6 +1145,43 @@ int main(int argc, char *argv[]) {
                 break;
             }
     
+            // Handle ping frame
+            if (frame_type == 0x89) {
+                if (config.debug) {
+                    printf("[DEBUG] Received ping frame, sending pong\n");
+                    fflush(stdout);
+                }
+                // Parse the ping frame to get payload
+                char *ping_payload;
+                int ping_payload_len;
+                if (parse_websocket_frame(buffer, bytes_read, &ping_payload, &ping_payload_len)) {
+                    // Send pong with same payload
+                    if (!send_pong_frame(active_tunnel->ssl, ping_payload, ping_payload_len)) {
+                        if (config.debug) {
+                            printf("[DEBUG] Failed to send pong frame\n");
+                            fflush(stdout);
+                        }
+                    }
+                } else {
+                    if (config.debug) {
+                        printf("[DEBUG] Failed to parse ping frame\n");
+                        fflush(stdout);
+                    }
+                }
+                continue;
+            }
+    
+            // Handle pong frame
+            if (frame_type == 0x8A) {
+                if (config.debug) {
+                    printf("[DEBUG] Received pong frame\n");
+                    fflush(stdout);
+                }
+                // Just acknowledge, no response needed
+                continue;
+            }
+    
+            // Handle regular frames (text/binary)
             char *payload;
             int payload_len;
             if (!parse_websocket_frame(buffer, bytes_read, &payload, &payload_len)) {