1/* SPDX-License-Identifier: GPL-2.0-or-later */ 2/* 3 * PTP 1588 support 4 * 5 * This file implements a BPF that recognizes PTP event messages. 6 * 7 * Copyright (C) 2010 OMICRON electronics GmbH 8 */ 9 10#ifndef _PTP_CLASSIFY_H_ 11#define _PTP_CLASSIFY_H_ 12 13#include <asm/unaligned.h> 14#include <linux/ip.h> 15#include <linux/ktime.h> 16#include <linux/skbuff.h> 17#include <linux/udp.h> 18#include <net/checksum.h> 19 20#define PTP_CLASS_NONE 0x00 /* not a PTP event message */ 21#define PTP_CLASS_V1 0x01 /* protocol version 1 */ 22#define PTP_CLASS_V2 0x02 /* protocol version 2 */ 23#define PTP_CLASS_VMASK 0x0f /* max protocol version is 15 */ 24#define PTP_CLASS_IPV4 0x10 /* event in an IPV4 UDP packet */ 25#define PTP_CLASS_IPV6 0x20 /* event in an IPV6 UDP packet */ 26#define PTP_CLASS_L2 0x40 /* event in a L2 packet */ 27#define PTP_CLASS_PMASK 0x70 /* mask for the packet type field */ 28#define PTP_CLASS_VLAN 0x80 /* event in a VLAN tagged packet */ 29 30#define PTP_CLASS_V1_IPV4 (PTP_CLASS_V1 | PTP_CLASS_IPV4) 31#define PTP_CLASS_V1_IPV6 (PTP_CLASS_V1 | PTP_CLASS_IPV6) /* probably DNE */ 32#define PTP_CLASS_V2_IPV4 (PTP_CLASS_V2 | PTP_CLASS_IPV4) 33#define PTP_CLASS_V2_IPV6 (PTP_CLASS_V2 | PTP_CLASS_IPV6) 34#define PTP_CLASS_V2_L2 (PTP_CLASS_V2 | PTP_CLASS_L2) 35#define PTP_CLASS_V2_VLAN (PTP_CLASS_V2 | PTP_CLASS_VLAN) 36#define PTP_CLASS_L4 (PTP_CLASS_IPV4 | PTP_CLASS_IPV6) 37 38#define PTP_MSGTYPE_SYNC 0x0 39#define PTP_MSGTYPE_DELAY_REQ 0x1 40#define PTP_MSGTYPE_PDELAY_REQ 0x2 41#define PTP_MSGTYPE_PDELAY_RESP 0x3 42 43#define PTP_EV_PORT 319 44#define PTP_GEN_PORT 320 45#define PTP_GEN_BIT 0x08 /* indicates general message, if set in message type */ 46 47#define OFF_PTP_SOURCE_UUID 22 /* PTPv1 only */ 48#define OFF_PTP_SEQUENCE_ID 30 49 50/* PTP header flag fields */ 51#define PTP_FLAG_TWOSTEP BIT(1) 52 53/* Below defines should actually be removed at some point in time. */ 54#define IP6_HLEN 40 55#define UDP_HLEN 8 56#define OFF_IHL 14 57#define IPV4_HLEN(data) (((struct iphdr *)(data + OFF_IHL))->ihl << 2) 58 59struct clock_identity { 60 u8 id[8]; 61} __packed; 62 63struct port_identity { 64 struct clock_identity clock_identity; 65 __be16 port_number; 66} __packed; 67 68struct ptp_header { 69 u8 tsmt; /* transportSpecific | messageType */ 70 u8 ver; /* reserved | versionPTP */ 71 __be16 message_length; 72 u8 domain_number; 73 u8 reserved1; 74 u8 flag_field[2]; 75 __be64 correction; 76 __be32 reserved2; 77 struct port_identity source_port_identity; 78 __be16 sequence_id; 79 u8 control; 80 u8 log_message_interval; 81} __packed; 82 83#if defined(CONFIG_NET_PTP_CLASSIFY) 84/** 85 * ptp_classify_raw - classify a PTP packet 86 * @skb: buffer 87 * 88 * Runs a minimal BPF dissector to classify a network packet to 89 * determine the PTP class. In case the skb does not contain any 90 * PTP protocol data, PTP_CLASS_NONE will be returned, otherwise 91 * PTP_CLASS_V1_IPV{4,6}, PTP_CLASS_V2_IPV{4,6} or 92 * PTP_CLASS_V2_{L2,VLAN}, depending on the packet content. 93 */ 94unsigned int ptp_classify_raw(const struct sk_buff *skb); 95 96/** 97 * ptp_parse_header - Get pointer to the PTP v2 header 98 * @skb: packet buffer 99 * @type: type of the packet (see ptp_classify_raw()) 100 * 101 * This function takes care of the VLAN, UDP, IPv4 and IPv6 headers. The length 102 * is checked. 103 * 104 * Note, internally skb_mac_header() is used. Make sure that the @skb is 105 * initialized accordingly. 106 * 107 * Return: Pointer to the ptp v2 header or NULL if not found 108 */ 109struct ptp_header *ptp_parse_header(struct sk_buff *skb, unsigned int type); 110 111/** 112 * ptp_get_msgtype - Extract ptp message type from given header 113 * @hdr: ptp header 114 * @type: type of the packet (see ptp_classify_raw()) 115 * 116 * This function returns the message type for a given ptp header. It takes care 117 * of the different ptp header versions (v1 or v2). 118 * 119 * Return: The message type 120 */ 121static inline u8 ptp_get_msgtype(const struct ptp_header *hdr, 122 unsigned int type) 123{ 124 u8 msgtype; 125 126 if (unlikely(type & PTP_CLASS_V1)) { 127 /* msg type is located at the control field for ptp v1 */ 128 msgtype = hdr->control; 129 } else { 130 msgtype = hdr->tsmt & 0x0f; 131 } 132 133 return msgtype; 134} 135 136/** 137 * ptp_check_diff8 - Computes new checksum (when altering a 64-bit field) 138 * @old: old field value 139 * @new: new field value 140 * @oldsum: previous checksum 141 * 142 * This function can be used to calculate a new checksum when only a single 143 * field is changed. Similar as ip_vs_check_diff*() in ip_vs.h. 144 * 145 * Return: Updated checksum 146 */ 147static inline __wsum ptp_check_diff8(__be64 old, __be64 new, __wsum oldsum) 148{ 149 __be64 diff[2] = { ~old, new }; 150 151 return csum_partial(diff, sizeof(diff), oldsum); 152} 153 154/** 155 * ptp_header_update_correction - Update PTP header's correction field 156 * @skb: packet buffer 157 * @type: type of the packet (see ptp_classify_raw()) 158 * @hdr: ptp header 159 * @correction: new correction value 160 * 161 * This updates the correction field of a PTP header and updates the UDP 162 * checksum (if UDP is used as transport). It is needed for hardware capable of 163 * one-step P2P that does not already modify the correction field of Pdelay_Req 164 * event messages on ingress. 165 */ 166static inline 167void ptp_header_update_correction(struct sk_buff *skb, unsigned int type, 168 struct ptp_header *hdr, s64 correction) 169{ 170 __be64 correction_old; 171 struct udphdr *uhdr; 172 173 /* previous correction value is required for checksum update. */ 174 memcpy(&correction_old, &hdr->correction, sizeof(correction_old)); 175 176 /* write new correction value */ 177 put_unaligned_be64((u64)correction, &hdr->correction); 178 179 switch (type & PTP_CLASS_PMASK) { 180 case PTP_CLASS_IPV4: 181 case PTP_CLASS_IPV6: 182 /* locate udp header */ 183 uhdr = (struct udphdr *)((char *)hdr - sizeof(struct udphdr)); 184 break; 185 default: 186 return; 187 } 188 189 /* update checksum */ 190 uhdr->check = csum_fold(ptp_check_diff8(correction_old, 191 hdr->correction, 192 ~csum_unfold(uhdr->check))); 193 if (!uhdr->check) 194 uhdr->check = CSUM_MANGLED_0; 195 196 skb->ip_summed = CHECKSUM_NONE; 197} 198 199/** 200 * ptp_msg_is_sync - Evaluates whether the given skb is a PTP Sync message 201 * @skb: packet buffer 202 * @type: type of the packet (see ptp_classify_raw()) 203 * 204 * This function evaluates whether the given skb is a PTP Sync message. 205 * 206 * Return: true if sync message, false otherwise 207 */ 208bool ptp_msg_is_sync(struct sk_buff *skb, unsigned int type); 209 210void __init ptp_classifier_init(void); 211#else 212static inline void ptp_classifier_init(void) 213{ 214} 215static inline unsigned int ptp_classify_raw(struct sk_buff *skb) 216{ 217 return PTP_CLASS_NONE; 218} 219static inline struct ptp_header *ptp_parse_header(struct sk_buff *skb, 220 unsigned int type) 221{ 222 return NULL; 223} 224static inline u8 ptp_get_msgtype(const struct ptp_header *hdr, 225 unsigned int type) 226{ 227 /* The return is meaningless. The stub function would not be 228 * executed since no available header from ptp_parse_header. 229 */ 230 return PTP_MSGTYPE_SYNC; 231} 232static inline bool ptp_msg_is_sync(struct sk_buff *skb, unsigned int type) 233{ 234 return false; 235} 236 237static inline 238void ptp_header_update_correction(struct sk_buff *skb, unsigned int type, 239 struct ptp_header *hdr, s64 correction) 240{ 241} 242#endif 243#endif /* _PTP_CLASSIFY_H_ */ 244