diff --git a/libc/kernel/uapi/linux/icmp.h b/libc/kernel/uapi/linux/icmp.h
index 03aa087..5892d12 100644
--- a/libc/kernel/uapi/linux/icmp.h
+++ b/libc/kernel/uapi/linux/icmp.h
@@ -19,6 +19,7 @@
 #ifndef _UAPI_LINUX_ICMP_H
 #define _UAPI_LINUX_ICMP_H
 #include <linux/types.h>
+#include <asm/byteorder.h>
 #define ICMP_ECHOREPLY 0
 #define ICMP_DEST_UNREACH 3
 #define ICMP_SOURCE_QUENCH 4
@@ -77,4 +78,20 @@
 struct icmp_filter {
   __u32 data;
 };
+struct icmp_ext_hdr {
+#ifdef __LITTLE_ENDIAN_BITFIELD
+  __u8 reserved1 : 4, version : 4;
+#elif defined(__BIG_ENDIAN_BITFIELD)
+  __u8 version : 4, reserved1 : 4;
+#else
+#error "Please fix <asm/byteorder.h>"
+#endif
+  __u8 reserved2;
+  __sum16 checksum;
+};
+struct icmp_extobj_hdr {
+  __be16 length;
+  __u8 class_num;
+  __u8 class_type;
+};
 #endif