include/linux/ppp_defs.h

0001 /* SPDX-License-Identifier: GPL-2.0-only */
0002 /*
0003  * ppp_defs.h - PPP definitions.
0004  *
0005  * Copyright 1994-2000 Paul Mackerras.
0006  */
0007 #ifndef _PPP_DEFS_H_
0008 #define _PPP_DEFS_H_
0009
0010 #include <linux/crc-ccitt.h>
0011 #include <uapi/linux/ppp_defs.h>
0012
0013 #define PPP_FCS(fcs, c) crc_ccitt_byte(fcs, c)
0014
0015 /**
0016  * ppp_proto_is_valid - checks if PPP protocol is valid
0017  * @proto: PPP protocol
0018  *
0019  * Assumes proto is not compressed.
0020  * Protocol is valid if the value is odd and the least significant bit of the
0021  * most significant octet is 0 (see RFC 1661, section 2).
0022  */
0023 static inline bool ppp_proto_is_valid(u16 proto)
0024 {
0025     return !!((proto & 0x0101) == 0x0001);
0026 }
0027
0028 #endif /* _PPP_DEFS_H_ */