encrypt overhead fix (33→36, noencrypt_len), mtu default 1280, connmonitor window, total_decrypted for TCP, check.sh

src/config_parser.c

@@ -846,7 +846,8 @@ static struct utun_config* parse_config_internal(FILE *fp, const char *filename)
 
     // Set default values
     cfg->global.name[0] = '\0';
-    cfg->global.keepalive_timeout = 2000;  // Default 2 seconds
+    cfg->global.mtu = 1280;                    // Default MTU: safe for IPv6 tunnels
+    cfg->global.keepalive_timeout = 2000;      // Default 2 seconds
     cfg->global.keepalive_interval = 200;   // Default 0.2 s
     cfg->global.keepalive_adaptive = 1;     // Default: adaptive enabled
     cfg->global.bbr_max_cwnd = 1048576; // Default 1MB (was INFLIGHT_LIM_MAX)
@@ -1131,6 +1132,7 @@ struct utun_config* parse_config_from_buf(const char *buf, size_t len, const cha
     struct utun_config *cfg = u_calloc(1, sizeof(struct utun_config));
     if (!cfg) { DEBUG_ERROR(DEBUG_CATEGORY_SYS, "failed to allocate memory for config structure"); return NULL; }
     cfg->global.name[0] = '\0';
+    cfg->global.mtu = 1280;
     cfg->global.keepalive_timeout = 2000;
     cfg->global.keepalive_interval = 200;
     cfg->global.keepalive_adaptive = 1;