xref: /openbmc/linux/include/linux/ptp_classify.h (revision 9a87ffc99ec8eb8d35eed7c4f816d75f5cc9662e)
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  
59  struct clock_identity {
60  	u8 id[8];
61  } __packed;
62  
63  struct port_identity {
64  	struct clock_identity	clock_identity;
65  	__be16			port_number;
66  } __packed;
67  
68  struct 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   */
94  unsigned 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   */
109  struct 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   */
ptp_get_msgtype(const struct ptp_header * hdr,unsigned int type)121  static 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   */
ptp_check_diff8(__be64 old,__be64 new,__wsum oldsum)147  static 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   */
166  static inline
ptp_header_update_correction(struct sk_buff * skb,unsigned int type,struct ptp_header * hdr,s64 correction)167  void 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   */
208  bool ptp_msg_is_sync(struct sk_buff *skb, unsigned int type);
209  
210  void __init ptp_classifier_init(void);
211  #else
ptp_classifier_init(void)212  static inline void ptp_classifier_init(void)
213  {
214  }
ptp_classify_raw(struct sk_buff * skb)215  static inline unsigned int ptp_classify_raw(struct sk_buff *skb)
216  {
217  	return PTP_CLASS_NONE;
218  }
ptp_parse_header(struct sk_buff * skb,unsigned int type)219  static inline struct ptp_header *ptp_parse_header(struct sk_buff *skb,
220  						  unsigned int type)
221  {
222  	return NULL;
223  }
ptp_get_msgtype(const struct ptp_header * hdr,unsigned int type)224  static 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  }
ptp_msg_is_sync(struct sk_buff * skb,unsigned int type)232  static inline bool ptp_msg_is_sync(struct sk_buff *skb, unsigned int type)
233  {
234  	return false;
235  }
236  
237  static inline
ptp_header_update_correction(struct sk_buff * skb,unsigned int type,struct ptp_header * hdr,s64 correction)238  void 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