|  | /* 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_ */ |