diff --git a/libc/kernel/uapi/linux/tcp.h b/libc/kernel/uapi/linux/tcp.h
index 4cae8d8..823583d 100644
--- a/libc/kernel/uapi/linux/tcp.h
+++ b/libc/kernel/uapi/linux/tcp.h
@@ -113,6 +113,12 @@
   TCP_SEND_QUEUE,
   TCP_QUEUES_NR,
 };
+enum tcp_fastopen_client_fail {
+  TFO_STATUS_UNSPEC,
+  TFO_COOKIE_UNAVAILABLE,
+  TFO_DATA_NOT_ACKED,
+  TFO_SYN_RETRANSMITTED,
+};
 #define TCPI_OPT_TIMESTAMPS 1
 #define TCPI_OPT_SACK 2
 #define TCPI_OPT_WSCALE 4
@@ -139,7 +145,7 @@
   __u8 tcpi_backoff;
   __u8 tcpi_options;
   __u8 tcpi_snd_wscale : 4, tcpi_rcv_wscale : 4;
-  __u8 tcpi_delivery_rate_app_limited : 1;
+  __u8 tcpi_delivery_rate_app_limited : 1, tcpi_fastopen_client_fail : 2;
   __u32 tcpi_rto;
   __u32 tcpi_ato;
   __u32 tcpi_snd_mss;