1#ifndef __LINUX_ERSPAN_H
2#define __LINUX_ERSPAN_H
3
4/*
5 * GRE header for ERSPAN type I encapsulation (4 octets [34:37])
6 *      0                   1                   2                   3
7 *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
8 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
9 *     |0|0|0|0|0|00000|000000000|00000|    Protocol Type for ERSPAN   |
10 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
11 *
12 *  The Type I ERSPAN frame format is based on the barebones IP + GRE
13 *  encapsulation (as described above) on top of the raw mirrored frame.
14 *  There is no extra ERSPAN header.
15 *
16 *
17 * GRE header for ERSPAN type II and II encapsulation (8 octets [34:41])
18 *       0                   1                   2                   3
19 *      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
20 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
21 *     |0|0|0|1|0|00000|000000000|00000|    Protocol Type for ERSPAN   |
22 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
23 *     |      Sequence Number (increments per packet per session)      |
24 *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
25 *
26 *  Note that in the above GRE header [RFC1701] out of the C, R, K, S,
27 *  s, Recur, Flags, Version fields only S (bit 03) is set to 1. The
28 *  other fields are set to zero, so only a sequence number follows.
29 *
30 *  ERSPAN Version 1 (Type II) header (8 octets [42:49])
31 *  0                   1                   2                   3
32 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
33 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
34 * |  Ver  |          VLAN         | COS | En|T|    Session ID     |
35 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
36 * |      Reserved         |                  Index                |
37 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
38 *
39 *
40 *  ERSPAN Version 2 (Type III) header (12 octets [42:49])
41 *  0                   1                   2                   3
42 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
43 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
44 * |  Ver  |          VLAN         | COS |BSO|T|     Session ID    |
45 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
46 * |                          Timestamp                            |
47 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
48 * |             SGT               |P|    FT   |   Hw ID   |D|Gra|O|
49 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
50 *
51 *      Platform Specific SubHeader (8 octets, optional)
52 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
53 * |  Platf ID |               Platform Specific Info              |
54 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
55 * |                  Platform Specific Info                       |
56 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
57 *
58 * GRE proto ERSPAN type I/II = 0x88BE, type III = 0x22EB
59 */
60
61#include <linux/ip.h>
62#include <linux/ipv6.h>
63#include <linux/skbuff.h>
64#include <uapi/linux/erspan.h>
65
66#define ERSPAN_VERSION	0x1	/* ERSPAN type II */
67#define VER_MASK	0xf000
68#define VLAN_MASK	0x0fff
69#define COS_MASK	0xe000
70#define EN_MASK		0x1800
71#define T_MASK		0x0400
72#define ID_MASK		0x03ff
73#define INDEX_MASK	0xfffff
74
75#define ERSPAN_VERSION2	0x2	/* ERSPAN type III*/
76#define BSO_MASK	EN_MASK
77#define SGT_MASK	0xffff0000
78#define P_MASK		0x8000
79#define FT_MASK		0x7c00
80#define HWID_MASK	0x03f0
81#define DIR_MASK	0x0008
82#define GRA_MASK	0x0006
83#define O_MASK		0x0001
84
85#define HWID_OFFSET    4
86#define DIR_OFFSET     3
87
88enum erspan_encap_type {
89	ERSPAN_ENCAP_NOVLAN = 0x0,	/* originally without VLAN tag */
90	ERSPAN_ENCAP_ISL = 0x1,		/* originally ISL encapsulated */
91	ERSPAN_ENCAP_8021Q = 0x2,	/* originally 802.1Q encapsulated */
92	ERSPAN_ENCAP_INFRAME = 0x3,	/* VLAN tag perserved in frame */
93};
94
95#define ERSPAN_V1_MDSIZE	4
96#define ERSPAN_V2_MDSIZE	8
97
98struct erspan_base_hdr {
99#if defined(__LITTLE_ENDIAN_BITFIELD)
100	__u8	vlan_upper:4,
101		ver:4;
102	__u8	vlan:8;
103	__u8	session_id_upper:2,
104		t:1,
105		en:2,
106		cos:3;
107	__u8	session_id:8;
108#elif defined(__BIG_ENDIAN_BITFIELD)
109	__u8	ver: 4,
110		vlan_upper:4;
111	__u8	vlan:8;
112	__u8	cos:3,
113		en:2,
114		t:1,
115		session_id_upper:2;
116	__u8	session_id:8;
117#else
118#error "Please fix <asm/byteorder.h>"
119#endif
120};
121
122static inline void set_session_id(struct erspan_base_hdr *ershdr, u16 id)
123{
124	ershdr->session_id = id & 0xff;
125	ershdr->session_id_upper = (id >> 8) & 0x3;
126}
127
128static inline u16 get_session_id(const struct erspan_base_hdr *ershdr)
129{
130	return (ershdr->session_id_upper << 8) + ershdr->session_id;
131}
132
133static inline void set_vlan(struct erspan_base_hdr *ershdr, u16 vlan)
134{
135	ershdr->vlan = vlan & 0xff;
136	ershdr->vlan_upper = (vlan >> 8) & 0xf;
137}
138
139static inline u16 get_vlan(const struct erspan_base_hdr *ershdr)
140{
141	return (ershdr->vlan_upper << 8) + ershdr->vlan;
142}
143
144static inline void set_hwid(struct erspan_md2 *md2, u8 hwid)
145{
146	md2->hwid = hwid & 0xf;
147	md2->hwid_upper = (hwid >> 4) & 0x3;
148}
149
150static inline u8 get_hwid(const struct erspan_md2 *md2)
151{
152	return (md2->hwid_upper << 4) + md2->hwid;
153}
154
155static inline int erspan_hdr_len(int version)
156{
157	if (version == 0)
158		return 0;
159
160	return sizeof(struct erspan_base_hdr) +
161	       (version == 1 ? ERSPAN_V1_MDSIZE : ERSPAN_V2_MDSIZE);
162}
163
164static inline u8 tos_to_cos(u8 tos)
165{
166	u8 dscp, cos;
167
168	dscp = tos >> 2;
169	cos = dscp >> 3;
170	return cos;
171}
172
173static inline void erspan_build_header(struct sk_buff *skb,
174				u32 id, u32 index,
175				bool truncate, bool is_ipv4)
176{
177	struct ethhdr *eth = (struct ethhdr *)skb->data;
178	enum erspan_encap_type enc_type;
179	struct erspan_base_hdr *ershdr;
180	struct qtag_prefix {
181		__be16 eth_type;
182		__be16 tci;
183	} *qp;
184	u16 vlan_tci = 0;
185	u8 tos;
186	__be32 *idx;
187
188	tos = is_ipv4 ? ip_hdr(skb)->tos :
189			(ipv6_hdr(skb)->priority << 4) +
190			(ipv6_hdr(skb)->flow_lbl[0] >> 4);
191
192	enc_type = ERSPAN_ENCAP_NOVLAN;
193
194	/* If mirrored packet has vlan tag, extract tci and
195	 *  perserve vlan header in the mirrored frame.
196	 */
197	if (eth->h_proto == htons(ETH_P_8021Q)) {
198		qp = (struct qtag_prefix *)(skb->data + 2 * ETH_ALEN);
199		vlan_tci = ntohs(qp->tci);
200		enc_type = ERSPAN_ENCAP_INFRAME;
201	}
202
203	skb_push(skb, sizeof(*ershdr) + ERSPAN_V1_MDSIZE);
204	ershdr = (struct erspan_base_hdr *)skb->data;
205	memset(ershdr, 0, sizeof(*ershdr) + ERSPAN_V1_MDSIZE);
206
207	/* Build base header */
208	ershdr->ver = ERSPAN_VERSION;
209	ershdr->cos = tos_to_cos(tos);
210	ershdr->en = enc_type;
211	ershdr->t = truncate;
212	set_vlan(ershdr, vlan_tci);
213	set_session_id(ershdr, id);
214
215	/* Build metadata */
216	idx = (__be32 *)(ershdr + 1);
217	*idx = htonl(index & INDEX_MASK);
218}
219
220/* ERSPAN GRA: timestamp granularity
221 *   00b --> granularity = 100 microseconds
222 *   01b --> granularity = 100 nanoseconds
223 *   10b --> granularity = IEEE 1588
224 * Here we only support 100 microseconds.
225 */
226static inline __be32 erspan_get_timestamp(void)
227{
228	u64 h_usecs;
229	ktime_t kt;
230
231	kt = ktime_get_real();
232	h_usecs = ktime_divns(kt, 100 * NSEC_PER_USEC);
233
234	/* ERSPAN base header only has 32-bit,
235	 * so it wraps around 4 days.
236	 */
237	return htonl((u32)h_usecs);
238}
239
240/* ERSPAN BSO (Bad/Short/Oversized), see RFC1757
241 *   00b --> Good frame with no error, or unknown integrity
242 *   01b --> Payload is a Short Frame
243 *   10b --> Payload is an Oversized Frame
244 *   11b --> Payload is a Bad Frame with CRC or Alignment Error
245 */
246enum erspan_bso {
247	BSO_NOERROR = 0x0,
248	BSO_SHORT = 0x1,
249	BSO_OVERSIZED = 0x2,
250	BSO_BAD = 0x3,
251};
252
253static inline u8 erspan_detect_bso(struct sk_buff *skb)
254{
255	/* BSO_BAD is not handled because the frame CRC
256	 * or alignment error information is in FCS.
257	 */
258	if (skb->len < ETH_ZLEN)
259		return BSO_SHORT;
260
261	if (skb->len > ETH_FRAME_LEN)
262		return BSO_OVERSIZED;
263
264	return BSO_NOERROR;
265}
266
267static inline void erspan_build_header_v2(struct sk_buff *skb,
268					  u32 id, u8 direction, u16 hwid,
269					  bool truncate, bool is_ipv4)
270{
271	struct ethhdr *eth = (struct ethhdr *)skb->data;
272	struct erspan_base_hdr *ershdr;
273	struct erspan_md2 *md2;
274	struct qtag_prefix {
275		__be16 eth_type;
276		__be16 tci;
277	} *qp;
278	u16 vlan_tci = 0;
279	u8 gra = 0; /* 100 usec */
280	u8 bso = 0; /* Bad/Short/Oversized */
281	u8 sgt = 0;
282	u8 tos;
283
284	tos = is_ipv4 ? ip_hdr(skb)->tos :
285			(ipv6_hdr(skb)->priority << 4) +
286			(ipv6_hdr(skb)->flow_lbl[0] >> 4);
287
288	/* Unlike v1, v2 does not have En field,
289	 * so only extract vlan tci field.
290	 */
291	if (eth->h_proto == htons(ETH_P_8021Q)) {
292		qp = (struct qtag_prefix *)(skb->data + 2 * ETH_ALEN);
293		vlan_tci = ntohs(qp->tci);
294	}
295
296	bso = erspan_detect_bso(skb);
297	skb_push(skb, sizeof(*ershdr) + ERSPAN_V2_MDSIZE);
298	ershdr = (struct erspan_base_hdr *)skb->data;
299	memset(ershdr, 0, sizeof(*ershdr) + ERSPAN_V2_MDSIZE);
300
301	/* Build base header */
302	ershdr->ver = ERSPAN_VERSION2;
303	ershdr->cos = tos_to_cos(tos);
304	ershdr->en = bso;
305	ershdr->t = truncate;
306	set_vlan(ershdr, vlan_tci);
307	set_session_id(ershdr, id);
308
309	/* Build metadata */
310	md2 = (struct erspan_md2 *)(ershdr + 1);
311	md2->timestamp = erspan_get_timestamp();
312	md2->sgt = htons(sgt);
313	md2->p = 1;
314	md2->ft = 0;
315	md2->dir = direction;
316	md2->gra = gra;
317	md2->o = 0;
318	set_hwid(md2, hwid);
319}
320
321#endif
322