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ptp_classify.h
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1 /*
2  * PTP 1588 support
3  *
4  * This file implements a BPF that recognizes PTP event messages.
5  *
6  * Copyright (C) 2010 OMICRON electronics GmbH
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or
11  * (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21  */
22 
23 #ifndef _PTP_CLASSIFY_H_
24 #define _PTP_CLASSIFY_H_
25 
26 #include <linux/if_ether.h>
27 #include <linux/if_vlan.h>
28 #include <linux/ip.h>
29 #include <linux/filter.h>
30 #ifdef __KERNEL__
31 #include <linux/in.h>
32 #else
33 #include <netinet/in.h>
34 #endif
35 
36 #define PTP_CLASS_NONE 0x00 /* not a PTP event message */
37 #define PTP_CLASS_V1 0x01 /* protocol version 1 */
38 #define PTP_CLASS_V2 0x02 /* protocol version 2 */
39 #define PTP_CLASS_VMASK 0x0f /* max protocol version is 15 */
40 #define PTP_CLASS_IPV4 0x10 /* event in an IPV4 UDP packet */
41 #define PTP_CLASS_IPV6 0x20 /* event in an IPV6 UDP packet */
42 #define PTP_CLASS_L2 0x30 /* event in a L2 packet */
43 #define PTP_CLASS_VLAN 0x40 /* event in a VLAN tagged L2 packet */
44 #define PTP_CLASS_PMASK 0xf0 /* mask for the packet type field */
45 
46 #define PTP_CLASS_V1_IPV4 (PTP_CLASS_V1 | PTP_CLASS_IPV4)
47 #define PTP_CLASS_V1_IPV6 (PTP_CLASS_V1 | PTP_CLASS_IPV6) /*probably DNE*/
48 #define PTP_CLASS_V2_IPV4 (PTP_CLASS_V2 | PTP_CLASS_IPV4)
49 #define PTP_CLASS_V2_IPV6 (PTP_CLASS_V2 | PTP_CLASS_IPV6)
50 #define PTP_CLASS_V2_L2 (PTP_CLASS_V2 | PTP_CLASS_L2)
51 #define PTP_CLASS_V2_VLAN (PTP_CLASS_V2 | PTP_CLASS_VLAN)
52 
53 #define PTP_EV_PORT 319
54 #define PTP_GEN_BIT 0x08 /* indicates general message, if set in message type */
55 
56 #define OFF_ETYPE 12
57 #define OFF_IHL 14
58 #define OFF_FRAG 20
59 #define OFF_PROTO4 23
60 #define OFF_NEXT 6
61 #define OFF_UDP_DST 2
62 
63 #define OFF_PTP_SOURCE_UUID 22 /* PTPv1 only */
64 #define OFF_PTP_SEQUENCE_ID 30
65 #define OFF_PTP_CONTROL 32 /* PTPv1 only */
66 
67 #define IPV4_HLEN(data) (((struct iphdr *)(data + OFF_IHL))->ihl << 2)
68 
69 #define IP6_HLEN 40
70 #define UDP_HLEN 8
71 
72 #define RELOFF_DST4 (ETH_HLEN + OFF_UDP_DST)
73 #define OFF_DST6 (ETH_HLEN + IP6_HLEN + OFF_UDP_DST)
74 #define OFF_PTP6 (ETH_HLEN + IP6_HLEN + UDP_HLEN)
75 
76 #define OP_AND (BPF_ALU | BPF_AND | BPF_K)
77 #define OP_JEQ (BPF_JMP | BPF_JEQ | BPF_K)
78 #define OP_JSET (BPF_JMP | BPF_JSET | BPF_K)
79 #define OP_LDB (BPF_LD | BPF_B | BPF_ABS)
80 #define OP_LDH (BPF_LD | BPF_H | BPF_ABS)
81 #define OP_LDHI (BPF_LD | BPF_H | BPF_IND)
82 #define OP_LDX (BPF_LDX | BPF_B | BPF_MSH)
83 #define OP_OR (BPF_ALU | BPF_OR | BPF_K)
84 #define OP_RETA (BPF_RET | BPF_A)
85 #define OP_RETK (BPF_RET | BPF_K)
86 
87 static inline int ptp_filter_init(struct sock_filter *f, int len)
88 {
89  if (OP_LDH == f[0].code)
90  return sk_chk_filter(f, len);
91  else
92  return 0;
93 }
94 
95 #define PTP_FILTER \
96  {OP_LDH, 0, 0, OFF_ETYPE }, /* */ \
97  {OP_JEQ, 0, 12, ETH_P_IP }, /* f goto L20 */ \
98  {OP_LDB, 0, 0, OFF_PROTO4 }, /* */ \
99  {OP_JEQ, 0, 9, IPPROTO_UDP }, /* f goto L10 */ \
100  {OP_LDH, 0, 0, OFF_FRAG }, /* */ \
101  {OP_JSET, 7, 0, 0x1fff }, /* t goto L11 */ \
102  {OP_LDX, 0, 0, OFF_IHL }, /* */ \
103  {OP_LDHI, 0, 0, RELOFF_DST4 }, /* */ \
104  {OP_JEQ, 0, 4, PTP_EV_PORT }, /* f goto L12 */ \
105  {OP_LDHI, 0, 0, ETH_HLEN + UDP_HLEN }, /* */ \
106  {OP_AND, 0, 0, PTP_CLASS_VMASK }, /* */ \
107  {OP_OR, 0, 0, PTP_CLASS_IPV4 }, /* */ \
108  {OP_RETA, 0, 0, 0 }, /* */ \
109 /*L1x*/ {OP_RETK, 0, 0, PTP_CLASS_NONE }, /* */ \
110 /*L20*/ {OP_JEQ, 0, 9, ETH_P_IPV6 }, /* f goto L40 */ \
111  {OP_LDB, 0, 0, ETH_HLEN + OFF_NEXT }, /* */ \
112  {OP_JEQ, 0, 6, IPPROTO_UDP }, /* f goto L30 */ \
113  {OP_LDH, 0, 0, OFF_DST6 }, /* */ \
114  {OP_JEQ, 0, 4, PTP_EV_PORT }, /* f goto L31 */ \
115  {OP_LDH, 0, 0, OFF_PTP6 }, /* */ \
116  {OP_AND, 0, 0, PTP_CLASS_VMASK }, /* */ \
117  {OP_OR, 0, 0, PTP_CLASS_IPV6 }, /* */ \
118  {OP_RETA, 0, 0, 0 }, /* */ \
119 /*L3x*/ {OP_RETK, 0, 0, PTP_CLASS_NONE }, /* */ \
120 /*L40*/ {OP_JEQ, 0, 9, ETH_P_8021Q }, /* f goto L50 */ \
121  {OP_LDH, 0, 0, OFF_ETYPE + 4 }, /* */ \
122  {OP_JEQ, 0, 15, ETH_P_1588 }, /* f goto L60 */ \
123  {OP_LDB, 0, 0, ETH_HLEN + VLAN_HLEN }, /* */ \
124  {OP_AND, 0, 0, PTP_GEN_BIT }, /* */ \
125  {OP_JEQ, 0, 12, 0 }, /* f goto L6x */ \
126  {OP_LDH, 0, 0, ETH_HLEN + VLAN_HLEN }, /* */ \
127  {OP_AND, 0, 0, PTP_CLASS_VMASK }, /* */ \
128  {OP_OR, 0, 0, PTP_CLASS_VLAN }, /* */ \
129  {OP_RETA, 0, 0, 0 }, /* */ \
130 /*L50*/ {OP_JEQ, 0, 7, ETH_P_1588 }, /* f goto L61 */ \
131  {OP_LDB, 0, 0, ETH_HLEN }, /* */ \
132  {OP_AND, 0, 0, PTP_GEN_BIT }, /* */ \
133  {OP_JEQ, 0, 4, 0 }, /* f goto L6x */ \
134  {OP_LDH, 0, 0, ETH_HLEN }, /* */ \
135  {OP_AND, 0, 0, PTP_CLASS_VMASK }, /* */ \
136  {OP_OR, 0, 0, PTP_CLASS_L2 }, /* */ \
137  {OP_RETA, 0, 0, 0 }, /* */ \
138 /*L6x*/ {OP_RETK, 0, 0, PTP_CLASS_NONE },
139 
140 #endif
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