1 files changed, 28 insertions, 0 deletions
diff --git a/include/linux/ppp_defs.h b/include/linux/ppp_defs.h
new file mode 100644
index 000000000..b7e57fdbd
--- /dev/null
+++ b/include/linux/ppp_defs.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * ppp_defs.h - PPP definitions.
+ *
+ * Copyright 1994-2000 Paul Mackerras.
+ */
+#ifndef _PPP_DEFS_H_
+#define _PPP_DEFS_H_
+
+#include <linux/crc-ccitt.h>
+#include <uapi/linux/ppp_defs.h>
+
+#define PPP_FCS(fcs, c) crc_ccitt_byte(fcs, c)
+
+/**
+ * ppp_proto_is_valid - checks if PPP protocol is valid
+ * @proto: PPP protocol
+ *
+ * Assumes proto is not compressed.
+ * Protocol is valid if the value is odd and the least significant bit of the
+ * most significant octet is 0 (see RFC 1661, section 2).
+ */
+static inline bool ppp_proto_is_valid(u16 proto)
+{
+	return !!((proto & 0x0101) == 0x0001);
+}
+
+#endif /* _PPP_DEFS_H_ */