diff --git a/include/ntapi/nt_tty.h b/include/ntapi/nt_tty.h
index 8f33bc7..d8e2fc6 100644
--- a/include/ntapi/nt_tty.h
+++ b/include/ntapi/nt_tty.h
@@ -14,6 +14,32 @@
 #include "nt_port.h"
 #include "nt_termios.h"
 
+/* tty affiliation */
+typedef struct _nt_tty_affiliation {
+	char	group1[8];
+	char	group2[4];
+	char	group3[4];
+	char	group4[4];
+	char	group5[12];
+} nt_tty_affiliation;
+
+#define NT_TTY_AFFILIATION_GUID_DEFAULT	{0xeb564abf, 0x0714,0x4cc9,{0x83,0x55,0xf9,0x89,0xdb,0xab,0x49,0x5c}}
+#define NT_TTY_AFFILIATION_GUID_POSIX	{0xe35ed272, 0x9e55,0x46c1,{0x82,0x51,0x02,0x2a,0x59,0xe6,0xc4,0x80}}
+
+#define NT_TTY_AFFILIATION_DEFAULT {				\
+	{'e','b','5','6','4','a','b','f'},			\
+	{'0','7','1','4'},					\
+	{'4','c','c','9'},					\
+	{'8','3','5','5'},					\
+	{'f','9','8','9','d','b','a','b','4','9','5','c'}}
+
+#define NT_TTY_AFFILIATION_POSIX {				\
+	{'e','3','5','e','d','2','7','2'},			\
+	{'9','e','5','5'},					\
+	{'4','6','c','1'},					\
+	{'8','2','5','1'},					\
+	{'0','2','2','a','5','9','e','6','c','4','8','0'}}
+
 typedef enum _nt_tty_opcode {
 	NT_TTY_CLIENT_OPCODE_BASE	= 0x40000,
 	/* primary connection */