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2955762b37
For P2P delay measurement, the ingress time stamp of the PDelay_Req is required for the correction field of the PDelay_Resp. The application echoes back the correction field of the PDelay_Req when sending the PDelay_Resp. Some hardware (like the ZHAW InES PTP time stamping IP core) subtracts the ingress timestamp autonomously from the correction field, so that the hardware only needs to add the egress timestamp on tx. Other hardware (like the Microchip KSZ9563) reports the ingress time stamp via an interrupt and requires that the software provides this time stamp via tail-tag on tx. In order to avoid introducing a further application interface for this, the driver can simply emulate the behavior of the InES device and subtract the ingress time stamp in software from the correction field. On egress, the correction field can either be kept as it is (and the time stamp field in the tail-tag is set to zero) or move the value from the correction field back to the tail-tag. Changing the correction field requires updating the UDP checksum (if UDP is used as transport). Signed-off-by: Christian Eggers <ceggers@arri.de> Co-developed-by: Arun Ramadoss <arun.ramadoss@microchip.com> Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com> Signed-off-by: David S. Miller <davem@davemloft.net>
243 lines
6.9 KiB
C
243 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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