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 <linux/ip.h>
14 #include <linux/skbuff.h>
15
16 #define PTP_CLASS_NONE 0x00 /* not a PTP event message */
17 #define PTP_CLASS_V1 0x01 /* protocol version 1 */
18 #define PTP_CLASS_V2 0x02 /* protocol version 2 */
19 #define PTP_CLASS_VMASK 0x0f /* max protocol version is 15 */
20 #define PTP_CLASS_IPV4 0x10 /* event in an IPV4 UDP packet */
21 #define PTP_CLASS_IPV6 0x20 /* event in an IPV6 UDP packet */
22 #define PTP_CLASS_L2 0x40 /* event in a L2 packet */
23 #define PTP_CLASS_PMASK 0x70 /* mask for the packet type field */
24 #define PTP_CLASS_VLAN 0x80 /* event in a VLAN tagged packet */
25
26 #define PTP_CLASS_V1_IPV4 (PTP_CLASS_V1 | PTP_CLASS_IPV4)
27 #define PTP_CLASS_V1_IPV6 (PTP_CLASS_V1 | PTP_CLASS_IPV6) /* probably DNE */
28 #define PTP_CLASS_V2_IPV4 (PTP_CLASS_V2 | PTP_CLASS_IPV4)
29 #define PTP_CLASS_V2_IPV6 (PTP_CLASS_V2 | PTP_CLASS_IPV6)
30 #define PTP_CLASS_V2_L2 (PTP_CLASS_V2 | PTP_CLASS_L2)
31 #define PTP_CLASS_V2_VLAN (PTP_CLASS_V2 | PTP_CLASS_VLAN)
32 #define PTP_CLASS_L4 (PTP_CLASS_IPV4 | PTP_CLASS_IPV6)
33
34 #define PTP_EV_PORT 319
35 #define PTP_GEN_BIT 0x08 /* indicates general message, if set in message type */
36
37 #define OFF_PTP_SOURCE_UUID 22 /* PTPv1 only */
38 #define OFF_PTP_SEQUENCE_ID 30
39
40 /* Below defines should actually be removed at some point in time. */
41 #define IP6_HLEN 40
42 #define UDP_HLEN 8
43 #define OFF_IHL 14
44 #define IPV4_HLEN(data) (((struct iphdr *)(data + OFF_IHL))->ihl << 2)
45
46 struct clock_identity {
47 u8 id[8];
48 } __packed;
49
50 struct port_identity {
51 struct clock_identity clock_identity;
52 __be16 port_number;
53 } __packed;
54
55 struct ptp_header {
56 u8 tsmt; /* transportSpecific | messageType */
57 u8 ver; /* reserved | versionPTP */
58 __be16 message_length;
59 u8 domain_number;
60 u8 reserved1;
61 u8 flag_field[2];
62 __be64 correction;
63 __be32 reserved2;
64 struct port_identity source_port_identity;
65 __be16 sequence_id;
66 u8 control;
67 u8 log_message_interval;
68 } __packed;
69
70 #if defined(CONFIG_NET_PTP_CLASSIFY)
71 /**
72 * ptp_classify_raw - classify a PTP packet
73 * @skb: buffer
74 *
75 * Runs a minimal BPF dissector to classify a network packet to
76 * determine the PTP class. In case the skb does not contain any
77 * PTP protocol data, PTP_CLASS_NONE will be returned, otherwise
78 * PTP_CLASS_V1_IPV{4,6}, PTP_CLASS_V2_IPV{4,6} or
79 * PTP_CLASS_V2_{L2,VLAN}, depending on the packet content.
80 */
81 unsigned int ptp_classify_raw(const struct sk_buff *skb);
82
83 /**
84 * ptp_parse_header - Get pointer to the PTP v2 header
85 * @skb: packet buffer
86 * @type: type of the packet (see ptp_classify_raw())
87 *
88 * This function takes care of the VLAN, UDP, IPv4 and IPv6 headers. The length
89 * is checked.
90 *
91 * Note, internally skb_mac_header() is used. Make sure that the @skb is
92 * initialized accordingly.
93 *
94 * Return: Pointer to the ptp v2 header or NULL if not found
95 */
96 struct ptp_header *ptp_parse_header(struct sk_buff *skb, unsigned int type);
97
98 /**
99 * ptp_get_msgtype - Extract ptp message type from given header
100 * @hdr: ptp header
101 * @type: type of the packet (see ptp_classify_raw())
102 *
103 * This function returns the message type for a given ptp header. It takes care
104 * of the different ptp header versions (v1 or v2).
105 *
106 * Return: The message type
107 */
ptp_get_msgtype(const struct ptp_header * hdr,unsigned int type)108 static inline u8 ptp_get_msgtype(const struct ptp_header *hdr,
109 unsigned int type)
110 {
111 u8 msgtype;
112
113 if (unlikely(type & PTP_CLASS_V1)) {
114 /* msg type is located at the control field for ptp v1 */
115 msgtype = hdr->control;
116 } else {
117 msgtype = hdr->tsmt & 0x0f;
118 }
119
120 return msgtype;
121 }
122
123 void __init ptp_classifier_init(void);
124 #else
ptp_classifier_init(void)125 static inline void ptp_classifier_init(void)
126 {
127 }
ptp_classify_raw(struct sk_buff * skb)128 static inline unsigned int ptp_classify_raw(struct sk_buff *skb)
129 {
130 return PTP_CLASS_NONE;
131 }
ptp_parse_header(struct sk_buff * skb,unsigned int type)132 static inline struct ptp_header *ptp_parse_header(struct sk_buff *skb,
133 unsigned int type)
134 {
135 return NULL;
136 }
ptp_get_msgtype(const struct ptp_header * hdr,unsigned int type)137 static inline u8 ptp_get_msgtype(const struct ptp_header *hdr,
138 unsigned int type)
139 {
140 /* The return is meaningless. The stub function would not be
141 * executed since no available header from ptp_parse_header.
142 */
143 return 0;
144 }
145 #endif
146 #endif /* _PTP_CLASSIFY_H_ */
147