1/* PTP classifier
  2 *
  3 * This program is free software; you can redistribute it and/or
  4 * modify it under the terms of version 2 of the GNU General Public
  5 * License as published by the Free Software Foundation.
  6 *
  7 * This program is distributed in the hope that it will be useful, but
  8 * WITHOUT ANY WARRANTY; without even the implied warranty of
  9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 10 * General Public License for more details.
 11 */
 12
 13/* The below program is the bpf_asm (tools/net/) representation of
 14 * the opcode array in the ptp_filter structure.
 15 *
 16 * For convenience, this can easily be altered and reviewed with
 17 * bpf_asm and bpf_dbg, e.g. `./bpf_asm -c prog` where prog is a
 18 * simple file containing the below program:
 19 *
 20 * ldh [12]                        ; load ethertype
 21 *
 22 * ; PTP over UDP over IPv4 over Ethernet
 23 * test_ipv4:
 24 *   jneq #0x800, test_ipv6        ; ETH_P_IP ?
 25 *   ldb [23]                      ; load proto
 26 *   jneq #17, drop_ipv4           ; IPPROTO_UDP ?
 27 *   ldh [20]                      ; load frag offset field
 28 *   jset #0x1fff, drop_ipv4       ; don't allow fragments
 29 *   ldxb 4*([14]&0xf)             ; load IP header len
 30 *   ldh [x + 16]                  ; load UDP dst port
 31 *   jneq #319, drop_ipv4          ; is port PTP_EV_PORT ?
 32 *   ldh [x + 22]                  ; load payload
 33 *   and #0xf                      ; mask PTP_CLASS_VMASK
 34 *   or #0x10                      ; PTP_CLASS_IPV4
 35 *   ret a                         ; return PTP class
 36 *   drop_ipv4: ret #0x0           ; PTP_CLASS_NONE
 37 *
 38 * ; PTP over UDP over IPv6 over Ethernet
 39 * test_ipv6:
 40 *   jneq #0x86dd, test_8021q      ; ETH_P_IPV6 ?
 41 *   ldb [20]                      ; load proto
 42 *   jneq #17, drop_ipv6           ; IPPROTO_UDP ?
 43 *   ldh [56]                      ; load UDP dst port
 44 *   jneq #319, drop_ipv6          ; is port PTP_EV_PORT ?
 45 *   ldh [62]                      ; load payload
 46 *   and #0xf                      ; mask PTP_CLASS_VMASK
 47 *   or #0x20                      ; PTP_CLASS_IPV6
 48 *   ret a                         ; return PTP class
 49 *   drop_ipv6: ret #0x0           ; PTP_CLASS_NONE
 50 *
 51 * ; PTP over 802.1Q over Ethernet
 52 * test_8021q:
 53 *   jneq #0x8100, test_ieee1588   ; ETH_P_8021Q ?
 54 *   ldh [16]                      ; load inner type
 55 *   jneq #0x88f7, drop_ieee1588   ; ETH_P_1588 ?
 56 *   ldb [18]                      ; load payload
 57 *   and #0x8                      ; as we don't have ports here, test
 58 *   jneq #0x0, drop_ieee1588      ; for PTP_GEN_BIT and drop these
 59 *   ldh [18]                      ; reload payload
 60 *   and #0xf                      ; mask PTP_CLASS_VMASK
 61 *   or #0x40                      ; PTP_CLASS_V2_VLAN
 62 *   ret a                         ; return PTP class
 63 *
 64 * ; PTP over Ethernet
 65 * test_ieee1588:
 66 *   jneq #0x88f7, drop_ieee1588   ; ETH_P_1588 ?
 67 *   ldb [14]                      ; load payload
 68 *   and #0x8                      ; as we don't have ports here, test
 69 *   jneq #0x0, drop_ieee1588      ; for PTP_GEN_BIT and drop these
 70 *   ldh [14]                      ; reload payload
 71 *   and #0xf                      ; mask PTP_CLASS_VMASK
 72 *   or #0x30                      ; PTP_CLASS_L2
 73 *   ret a                         ; return PTP class
 74 *   drop_ieee1588: ret #0x0       ; PTP_CLASS_NONE
 75 */
 76
 77#include <linux/skbuff.h>
 78#include <linux/filter.h>
 79#include <linux/ptp_classify.h>
 80
 81static struct sk_filter *ptp_insns __read_mostly;
 82
 83unsigned int ptp_classify_raw(const struct sk_buff *skb)
 84{
 85	return SK_RUN_FILTER(ptp_insns, skb);
 86}
 87EXPORT_SYMBOL_GPL(ptp_classify_raw);
 88
 89void __init ptp_classifier_init(void)
 90{
 91	static struct sock_filter ptp_filter[] = {
 92		{ 0x28,  0,  0, 0x0000000c },
 93		{ 0x15,  0, 12, 0x00000800 },
 94		{ 0x30,  0,  0, 0x00000017 },
 95		{ 0x15,  0,  9, 0x00000011 },
 96		{ 0x28,  0,  0, 0x00000014 },
 97		{ 0x45,  7,  0, 0x00001fff },
 98		{ 0xb1,  0,  0, 0x0000000e },
 99		{ 0x48,  0,  0, 0x00000010 },
100		{ 0x15,  0,  4, 0x0000013f },
101		{ 0x48,  0,  0, 0x00000016 },
102		{ 0x54,  0,  0, 0x0000000f },
103		{ 0x44,  0,  0, 0x00000010 },
104		{ 0x16,  0,  0, 0x00000000 },
105		{ 0x06,  0,  0, 0x00000000 },
106		{ 0x15,  0,  9, 0x000086dd },
107		{ 0x30,  0,  0, 0x00000014 },
108		{ 0x15,  0,  6, 0x00000011 },
109		{ 0x28,  0,  0, 0x00000038 },
110		{ 0x15,  0,  4, 0x0000013f },
111		{ 0x28,  0,  0, 0x0000003e },
112		{ 0x54,  0,  0, 0x0000000f },
113		{ 0x44,  0,  0, 0x00000020 },
114		{ 0x16,  0,  0, 0x00000000 },
115		{ 0x06,  0,  0, 0x00000000 },
116		{ 0x15,  0,  9, 0x00008100 },
117		{ 0x28,  0,  0, 0x00000010 },
118		{ 0x15,  0, 15, 0x000088f7 },
119		{ 0x30,  0,  0, 0x00000012 },
120		{ 0x54,  0,  0, 0x00000008 },
121		{ 0x15,  0, 12, 0x00000000 },
122		{ 0x28,  0,  0, 0x00000012 },
123		{ 0x54,  0,  0, 0x0000000f },
124		{ 0x44,  0,  0, 0x00000040 },
125		{ 0x16,  0,  0, 0x00000000 },
126		{ 0x15,  0,  7, 0x000088f7 },
127		{ 0x30,  0,  0, 0x0000000e },
128		{ 0x54,  0,  0, 0x00000008 },
129		{ 0x15,  0,  4, 0x00000000 },
130		{ 0x28,  0,  0, 0x0000000e },
131		{ 0x54,  0,  0, 0x0000000f },
132		{ 0x44,  0,  0, 0x00000030 },
133		{ 0x16,  0,  0, 0x00000000 },
134		{ 0x06,  0,  0, 0x00000000 },
135	};
136	struct sock_fprog ptp_prog = {
137		.len = ARRAY_SIZE(ptp_filter), .filter = ptp_filter,
138	};
139
140	BUG_ON(sk_unattached_filter_create(&ptp_insns, &ptp_prog));
141}