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