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