1 // SPDX-License-Identifier: GPL-2.0-only
2 /* PTP classifier
3 */
4
5 /* The below program is the bpf_asm (tools/net/) representation of
6 * the opcode array in the ptp_filter structure.
7 *
8 * For convenience, this can easily be altered and reviewed with
9 * bpf_asm and bpf_dbg, e.g. `./bpf_asm -c prog` where prog is a
10 * simple file containing the below program:
11 *
12 * ldh [12] ; load ethertype
13 *
14 * ; PTP over UDP over IPv4 over Ethernet
15 * test_ipv4:
16 * jneq #0x800, test_ipv6 ; ETH_P_IP ?
17 * ldb [23] ; load proto
18 * jneq #17, drop_ipv4 ; IPPROTO_UDP ?
19 * ldh [20] ; load frag offset field
20 * jset #0x1fff, drop_ipv4 ; don't allow fragments
21 * ldxb 4*([14]&0xf) ; load IP header len
22 * ldh [x + 16] ; load UDP dst port
23 * jneq #319, drop_ipv4 ; is port PTP_EV_PORT ?
24 * ldh [x + 22] ; load payload
25 * and #0xf ; mask PTP_CLASS_VMASK
26 * or #0x10 ; PTP_CLASS_IPV4
27 * ret a ; return PTP class
28 * drop_ipv4: ret #0x0 ; PTP_CLASS_NONE
29 *
30 * ; PTP over UDP over IPv6 over Ethernet
31 * test_ipv6:
32 * jneq #0x86dd, test_8021q ; ETH_P_IPV6 ?
33 * ldb [20] ; load proto
34 * jneq #17, drop_ipv6 ; IPPROTO_UDP ?
35 * ldh [56] ; load UDP dst port
36 * jneq #319, drop_ipv6 ; is port PTP_EV_PORT ?
37 * ldh [62] ; load payload
38 * and #0xf ; mask PTP_CLASS_VMASK
39 * or #0x20 ; PTP_CLASS_IPV6
40 * ret a ; return PTP class
41 * drop_ipv6: ret #0x0 ; PTP_CLASS_NONE
42 *
43 * ; PTP over 802.1Q over Ethernet
44 * test_8021q:
45 * jneq #0x8100, test_ieee1588 ; ETH_P_8021Q ?
46 * ldh [16] ; load inner type
47 * jneq #0x88f7, test_8021q_ipv4 ; ETH_P_1588 ?
48 * ldb [18] ; load payload
49 * and #0x8 ; as we don't have ports here, test
50 * jneq #0x0, drop_ieee1588 ; for PTP_GEN_BIT and drop these
51 * ldh [18] ; reload payload
52 * and #0xf ; mask PTP_CLASS_VMASK
53 * or #0xc0 ; PTP_CLASS_VLAN|PTP_CLASS_L2
54 * ret a ; return PTP class
55 *
56 * ; PTP over UDP over IPv4 over 802.1Q over Ethernet
57 * test_8021q_ipv4:
58 * jneq #0x800, test_8021q_ipv6 ; ETH_P_IP ?
59 * ldb [27] ; load proto
60 * jneq #17, drop_8021q_ipv4 ; IPPROTO_UDP ?
61 * ldh [24] ; load frag offset field
62 * jset #0x1fff, drop_8021q_ipv4; don't allow fragments
63 * ldxb 4*([18]&0xf) ; load IP header len
64 * ldh [x + 20] ; load UDP dst port
65 * jneq #319, drop_8021q_ipv4 ; is port PTP_EV_PORT ?
66 * ldh [x + 26] ; load payload
67 * and #0xf ; mask PTP_CLASS_VMASK
68 * or #0x90 ; PTP_CLASS_VLAN|PTP_CLASS_IPV4
69 * ret a ; return PTP class
70 * drop_8021q_ipv4: ret #0x0 ; PTP_CLASS_NONE
71 *
72 * ; PTP over UDP over IPv6 over 802.1Q over Ethernet
73 * test_8021q_ipv6:
74 * jneq #0x86dd, drop_8021q_ipv6 ; ETH_P_IPV6 ?
75 * ldb [24] ; load proto
76 * jneq #17, drop_8021q_ipv6 ; IPPROTO_UDP ?
77 * ldh [60] ; load UDP dst port
78 * jneq #319, drop_8021q_ipv6 ; is port PTP_EV_PORT ?
79 * ldh [66] ; load payload
80 * and #0xf ; mask PTP_CLASS_VMASK
81 * or #0xa0 ; PTP_CLASS_VLAN|PTP_CLASS_IPV6
82 * ret a ; return PTP class
83 * drop_8021q_ipv6: ret #0x0 ; PTP_CLASS_NONE
84 *
85 * ; PTP over Ethernet
86 * test_ieee1588:
87 * jneq #0x88f7, drop_ieee1588 ; ETH_P_1588 ?
88 * ldb [14] ; load payload
89 * and #0x8 ; as we don't have ports here, test
90 * jneq #0x0, drop_ieee1588 ; for PTP_GEN_BIT and drop these
91 * ldh [14] ; reload payload
92 * and #0xf ; mask PTP_CLASS_VMASK
93 * or #0x40 ; PTP_CLASS_L2
94 * ret a ; return PTP class
95 * drop_ieee1588: ret #0x0 ; PTP_CLASS_NONE
96 */
97
98 #include <linux/skbuff.h>
99 #include <linux/filter.h>
100 #include <linux/ptp_classify.h>
101
102 static struct bpf_prog *ptp_insns __read_mostly;
103
104 unsigned int ptp_classify_raw(const struct sk_buff *skb)
105 {
106 return bpf_prog_run(ptp_insns, skb);
107 }
108 EXPORT_SYMBOL_GPL(ptp_classify_raw);
109
110 struct ptp_header *ptp_parse_header(struct sk_buff *skb, unsigned int type)
111 {
112 u8 *ptr = skb_mac_header(skb);
113
114 if (type & PTP_CLASS_VLAN)
115 ptr += VLAN_HLEN;
116
117 switch (type & PTP_CLASS_PMASK) {
118 case PTP_CLASS_IPV4:
119 ptr += IPV4_HLEN(ptr) + UDP_HLEN;
120 break;
121 case PTP_CLASS_IPV6:
122 ptr += IP6_HLEN + UDP_HLEN;
123 break;
124 case PTP_CLASS_L2:
125 break;
126 default:
127 return NULL;
128 }
129
130 ptr += ETH_HLEN;
131
132 /* Ensure that the entire header is present in this packet. */
133 if (ptr + sizeof(struct ptp_header) > skb->data + skb->len)
134 return NULL;
135
136 return (struct ptp_header *)ptr;
137 }
138 EXPORT_SYMBOL_GPL(ptp_parse_header);
139
140 bool ptp_msg_is_sync(struct sk_buff *skb, unsigned int type)
141 {
142 struct ptp_header *hdr;
143
144 hdr = ptp_parse_header(skb, type);
145 if (!hdr)
146 return false;
147
148 return ptp_get_msgtype(hdr, type) == PTP_MSGTYPE_SYNC;
149 }
150 EXPORT_SYMBOL_GPL(ptp_msg_is_sync);
151
152 void __init ptp_classifier_init(void)
153 {
154 static struct sock_filter ptp_filter[] __initdata = {
155 { 0x28, 0, 0, 0x0000000c },
156 { 0x15, 0, 12, 0x00000800 },
157 { 0x30, 0, 0, 0x00000017 },
158 { 0x15, 0, 9, 0x00000011 },
159 { 0x28, 0, 0, 0x00000014 },
160 { 0x45, 7, 0, 0x00001fff },
161 { 0xb1, 0, 0, 0x0000000e },
162 { 0x48, 0, 0, 0x00000010 },
163 { 0x15, 0, 4, 0x0000013f },
164 { 0x48, 0, 0, 0x00000016 },
165 { 0x54, 0, 0, 0x0000000f },
166 { 0x44, 0, 0, 0x00000010 },
167 { 0x16, 0, 0, 0x00000000 },
168 { 0x06, 0, 0, 0x00000000 },
169 { 0x15, 0, 9, 0x000086dd },
170 { 0x30, 0, 0, 0x00000014 },
171 { 0x15, 0, 6, 0x00000011 },
172 { 0x28, 0, 0, 0x00000038 },
173 { 0x15, 0, 4, 0x0000013f },
174 { 0x28, 0, 0, 0x0000003e },
175 { 0x54, 0, 0, 0x0000000f },
176 { 0x44, 0, 0, 0x00000020 },
177 { 0x16, 0, 0, 0x00000000 },
178 { 0x06, 0, 0, 0x00000000 },
179 { 0x15, 0, 32, 0x00008100 },
180 { 0x28, 0, 0, 0x00000010 },
181 { 0x15, 0, 7, 0x000088f7 },
182 { 0x30, 0, 0, 0x00000012 },
183 { 0x54, 0, 0, 0x00000008 },
184 { 0x15, 0, 35, 0x00000000 },
185 { 0x28, 0, 0, 0x00000012 },
186 { 0x54, 0, 0, 0x0000000f },
187 { 0x44, 0, 0, 0x000000c0 },
188 { 0x16, 0, 0, 0x00000000 },
189 { 0x15, 0, 12, 0x00000800 },
190 { 0x30, 0, 0, 0x0000001b },
191 { 0x15, 0, 9, 0x00000011 },
192 { 0x28, 0, 0, 0x00000018 },
193 { 0x45, 7, 0, 0x00001fff },
194 { 0xb1, 0, 0, 0x00000012 },
195 { 0x48, 0, 0, 0x00000014 },
196 { 0x15, 0, 4, 0x0000013f },
197 { 0x48, 0, 0, 0x0000001a },
198 { 0x54, 0, 0, 0x0000000f },
199 { 0x44, 0, 0, 0x00000090 },
200 { 0x16, 0, 0, 0x00000000 },
201 { 0x06, 0, 0, 0x00000000 },
202 { 0x15, 0, 8, 0x000086dd },
203 { 0x30, 0, 0, 0x00000018 },
204 { 0x15, 0, 6, 0x00000011 },
205 { 0x28, 0, 0, 0x0000003c },
206 { 0x15, 0, 4, 0x0000013f },
207 { 0x28, 0, 0, 0x00000042 },
208 { 0x54, 0, 0, 0x0000000f },
209 { 0x44, 0, 0, 0x000000a0 },
210 { 0x16, 0, 0, 0x00000000 },
211 { 0x06, 0, 0, 0x00000000 },
212 { 0x15, 0, 7, 0x000088f7 },
213 { 0x30, 0, 0, 0x0000000e },
214 { 0x54, 0, 0, 0x00000008 },
215 { 0x15, 0, 4, 0x00000000 },
216 { 0x28, 0, 0, 0x0000000e },
217 { 0x54, 0, 0, 0x0000000f },
218 { 0x44, 0, 0, 0x00000040 },
219 { 0x16, 0, 0, 0x00000000 },
220 { 0x06, 0, 0, 0x00000000 },
221 };
222 struct sock_fprog_kern ptp_prog;
223
224 ptp_prog.len = ARRAY_SIZE(ptp_filter);
225 ptp_prog.filter = ptp_filter;
226
227 BUG_ON(bpf_prog_create(&ptp_insns, &ptp_prog));
228 }
229
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