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/* 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 <linux/skbuff.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);
}
/**
* ppp_skb_is_compressed_proto - checks if PPP protocol in a skb is compressed
* @skb: skb to check
*
* Check if the PPP protocol field is compressed (the least significant
* bit of the most significant octet is 1). skb->data must point to the PPP
* protocol header.
*
* Return: Whether the PPP protocol field is compressed.
*/
static inline bool ppp_skb_is_compressed_proto(const struct sk_buff *skb)
{
return unlikely(skb->data[0] & 0x01);
}
#endif /* _PPP_DEFS_H_ */
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