diff options
Diffstat (limited to 'include/linux/ppp_defs.h')
| -rw-r--r-- | include/linux/ppp_defs.h | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/include/linux/ppp_defs.h b/include/linux/ppp_defs.h index 28aa0237c8c3..b7e57fdbd413 100644 --- a/include/linux/ppp_defs.h +++ b/include/linux/ppp_defs.h @@ -1,11 +1,8 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ /* * ppp_defs.h - PPP definitions. * * Copyright 1994-2000 Paul Mackerras. - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * version 2 as published by the Free Software Foundation. */ #ifndef _PPP_DEFS_H_ #define _PPP_DEFS_H_ @@ -14,4 +11,18 @@ #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_ */ |