244 lines
6.9 KiB
C
244 lines
6.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* PTP 1588 support
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*
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* This file implements a BPF that recognizes PTP event messages.
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*
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* Copyright (C) 2010 OMICRON electronics GmbH
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*/
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#ifndef _PTP_CLASSIFY_H_
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#define _PTP_CLASSIFY_H_
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#include <asm/unaligned.h>
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#include <linux/ip.h>
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#include <linux/ktime.h>
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#include <linux/skbuff.h>
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#include <linux/udp.h>
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#include <net/checksum.h>
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#define PTP_CLASS_NONE 0x00 /* not a PTP event message */
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#define PTP_CLASS_V1 0x01 /* protocol version 1 */
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#define PTP_CLASS_V2 0x02 /* protocol version 2 */
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#define PTP_CLASS_VMASK 0x0f /* max protocol version is 15 */
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#define PTP_CLASS_IPV4 0x10 /* event in an IPV4 UDP packet */
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#define PTP_CLASS_IPV6 0x20 /* event in an IPV6 UDP packet */
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#define PTP_CLASS_L2 0x40 /* event in a L2 packet */
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#define PTP_CLASS_PMASK 0x70 /* mask for the packet type field */
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#define PTP_CLASS_VLAN 0x80 /* event in a VLAN tagged packet */
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#define PTP_CLASS_V1_IPV4 (PTP_CLASS_V1 | PTP_CLASS_IPV4)
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#define PTP_CLASS_V1_IPV6 (PTP_CLASS_V1 | PTP_CLASS_IPV6) /* probably DNE */
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#define PTP_CLASS_V2_IPV4 (PTP_CLASS_V2 | PTP_CLASS_IPV4)
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#define PTP_CLASS_V2_IPV6 (PTP_CLASS_V2 | PTP_CLASS_IPV6)
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#define PTP_CLASS_V2_L2 (PTP_CLASS_V2 | PTP_CLASS_L2)
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#define PTP_CLASS_V2_VLAN (PTP_CLASS_V2 | PTP_CLASS_VLAN)
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#define PTP_CLASS_L4 (PTP_CLASS_IPV4 | PTP_CLASS_IPV6)
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#define PTP_MSGTYPE_SYNC 0x0
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#define PTP_MSGTYPE_DELAY_REQ 0x1
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#define PTP_MSGTYPE_PDELAY_REQ 0x2
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#define PTP_MSGTYPE_PDELAY_RESP 0x3
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#define PTP_EV_PORT 319
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#define PTP_GEN_PORT 320
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#define PTP_GEN_BIT 0x08 /* indicates general message, if set in message type */
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#define OFF_PTP_SOURCE_UUID 22 /* PTPv1 only */
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#define OFF_PTP_SEQUENCE_ID 30
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/* PTP header flag fields */
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#define PTP_FLAG_TWOSTEP BIT(1)
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/* Below defines should actually be removed at some point in time. */
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#define IP6_HLEN 40
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#define UDP_HLEN 8
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#define OFF_IHL 14
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#define IPV4_HLEN(data) (((struct iphdr *)(data + OFF_IHL))->ihl << 2)
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struct clock_identity {
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u8 id[8];
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} __packed;
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struct port_identity {
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struct clock_identity clock_identity;
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__be16 port_number;
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} __packed;
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struct ptp_header {
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u8 tsmt; /* transportSpecific | messageType */
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u8 ver; /* reserved | versionPTP */
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__be16 message_length;
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u8 domain_number;
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u8 reserved1;
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u8 flag_field[2];
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__be64 correction;
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__be32 reserved2;
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struct port_identity source_port_identity;
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__be16 sequence_id;
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u8 control;
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u8 log_message_interval;
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} __packed;
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#if defined(CONFIG_NET_PTP_CLASSIFY)
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/**
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* ptp_classify_raw - classify a PTP packet
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* @skb: buffer
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*
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* Runs a minimal BPF dissector to classify a network packet to
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* determine the PTP class. In case the skb does not contain any
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* PTP protocol data, PTP_CLASS_NONE will be returned, otherwise
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* PTP_CLASS_V1_IPV{4,6}, PTP_CLASS_V2_IPV{4,6} or
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* PTP_CLASS_V2_{L2,VLAN}, depending on the packet content.
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*/
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unsigned int ptp_classify_raw(const struct sk_buff *skb);
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/**
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* ptp_parse_header - Get pointer to the PTP v2 header
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* @skb: packet buffer
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* @type: type of the packet (see ptp_classify_raw())
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*
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* This function takes care of the VLAN, UDP, IPv4 and IPv6 headers. The length
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* is checked.
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*
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* Note, internally skb_mac_header() is used. Make sure that the @skb is
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* initialized accordingly.
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*
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* Return: Pointer to the ptp v2 header or NULL if not found
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*/
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struct ptp_header *ptp_parse_header(struct sk_buff *skb, unsigned int type);
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/**
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* ptp_get_msgtype - Extract ptp message type from given header
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* @hdr: ptp header
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* @type: type of the packet (see ptp_classify_raw())
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*
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* This function returns the message type for a given ptp header. It takes care
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* of the different ptp header versions (v1 or v2).
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*
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* Return: The message type
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*/
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static inline u8 ptp_get_msgtype(const struct ptp_header *hdr,
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unsigned int type)
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{
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u8 msgtype;
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if (unlikely(type & PTP_CLASS_V1)) {
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/* msg type is located at the control field for ptp v1 */
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msgtype = hdr->control;
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} else {
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msgtype = hdr->tsmt & 0x0f;
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}
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return msgtype;
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}
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/**
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* ptp_check_diff8 - Computes new checksum (when altering a 64-bit field)
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* @old: old field value
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* @new: new field value
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* @oldsum: previous checksum
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*
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* This function can be used to calculate a new checksum when only a single
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* field is changed. Similar as ip_vs_check_diff*() in ip_vs.h.
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*
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* Return: Updated checksum
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*/
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static inline __wsum ptp_check_diff8(__be64 old, __be64 new, __wsum oldsum)
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{
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__be64 diff[2] = { ~old, new };
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return csum_partial(diff, sizeof(diff), oldsum);
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}
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/**
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* ptp_header_update_correction - Update PTP header's correction field
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* @skb: packet buffer
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* @type: type of the packet (see ptp_classify_raw())
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* @hdr: ptp header
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* @correction: new correction value
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*
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* This updates the correction field of a PTP header and updates the UDP
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* checksum (if UDP is used as transport). It is needed for hardware capable of
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* one-step P2P that does not already modify the correction field of Pdelay_Req
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* event messages on ingress.
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*/
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static inline
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void ptp_header_update_correction(struct sk_buff *skb, unsigned int type,
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struct ptp_header *hdr, s64 correction)
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{
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__be64 correction_old;
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struct udphdr *uhdr;
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/* previous correction value is required for checksum update. */
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memcpy(&correction_old, &hdr->correction, sizeof(correction_old));
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/* write new correction value */
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put_unaligned_be64((u64)correction, &hdr->correction);
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switch (type & PTP_CLASS_PMASK) {
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case PTP_CLASS_IPV4:
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case PTP_CLASS_IPV6:
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/* locate udp header */
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uhdr = (struct udphdr *)((char *)hdr - sizeof(struct udphdr));
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break;
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default:
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return;
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}
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/* update checksum */
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uhdr->check = csum_fold(ptp_check_diff8(correction_old,
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hdr->correction,
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~csum_unfold(uhdr->check)));
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if (!uhdr->check)
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uhdr->check = CSUM_MANGLED_0;
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skb->ip_summed = CHECKSUM_NONE;
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}
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/**
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* ptp_msg_is_sync - Evaluates whether the given skb is a PTP Sync message
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* @skb: packet buffer
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* @type: type of the packet (see ptp_classify_raw())
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*
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* This function evaluates whether the given skb is a PTP Sync message.
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*
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* Return: true if sync message, false otherwise
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*/
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bool ptp_msg_is_sync(struct sk_buff *skb, unsigned int type);
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void __init ptp_classifier_init(void);
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#else
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static inline void ptp_classifier_init(void)
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{
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}
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static inline unsigned int ptp_classify_raw(struct sk_buff *skb)
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{
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return PTP_CLASS_NONE;
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}
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static inline struct ptp_header *ptp_parse_header(struct sk_buff *skb,
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unsigned int type)
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{
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return NULL;
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}
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static inline u8 ptp_get_msgtype(const struct ptp_header *hdr,
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unsigned int type)
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{
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/* The return is meaningless. The stub function would not be
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* executed since no available header from ptp_parse_header.
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*/
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return PTP_MSGTYPE_SYNC;
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}
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static inline bool ptp_msg_is_sync(struct sk_buff *skb, unsigned int type)
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{
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return false;
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}
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static inline
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void ptp_header_update_correction(struct sk_buff *skb, unsigned int type,
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struct ptp_header *hdr, s64 correction)
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{
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}
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#endif
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#endif /* _PTP_CLASSIFY_H_ */
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