diff --git a/libc/kernel/uapi/linux/tls.h b/libc/kernel/uapi/linux/tls.h
index c98ea0b..4501cda 100644
--- a/libc/kernel/uapi/linux/tls.h
+++ b/libc/kernel/uapi/linux/tls.h
@@ -21,6 +21,7 @@
 #include <linux/types.h>
 #define TLS_TX 1
 #define TLS_RX 2
+#define TLS_TX_ZEROCOPY_RO 3
 #define TLS_VERSION_MINOR(ver) ((ver) & 0xFF)
 #define TLS_VERSION_MAJOR(ver) (((ver) >> 8) & 0xFF)
 #define TLS_VERSION_NUMBER(id) ((((id ##_VERSION_MAJOR) & 0xFF) << 8) | ((id ##_VERSION_MINOR) & 0xFF))
@@ -120,6 +121,7 @@
   TLS_INFO_CIPHER,
   TLS_INFO_TXCONF,
   TLS_INFO_RXCONF,
+  TLS_INFO_ZC_RO_TX,
   __TLS_INFO_MAX,
 };
 #define TLS_INFO_MAX (__TLS_INFO_MAX - 1)