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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 <uapi/linux/erspan.h>
62
63#define ERSPAN_VERSION 0x1 /* ERSPAN type II */
64#define VER_MASK 0xf000
65#define VLAN_MASK 0x0fff
66#define COS_MASK 0xe000
67#define EN_MASK 0x1800
68#define T_MASK 0x0400
69#define ID_MASK 0x03ff
70#define INDEX_MASK 0xfffff
71
72#define ERSPAN_VERSION2 0x2 /* ERSPAN type III*/
73#define BSO_MASK EN_MASK
74#define SGT_MASK 0xffff0000
75#define P_MASK 0x8000
76#define FT_MASK 0x7c00
77#define HWID_MASK 0x03f0
78#define DIR_MASK 0x0008
79#define GRA_MASK 0x0006
80#define O_MASK 0x0001
81
82#define HWID_OFFSET 4
83#define DIR_OFFSET 3
84
85enum erspan_encap_type {
86 ERSPAN_ENCAP_NOVLAN = 0x0, /* originally without VLAN tag */
87 ERSPAN_ENCAP_ISL = 0x1, /* originally ISL encapsulated */
88 ERSPAN_ENCAP_8021Q = 0x2, /* originally 802.1Q encapsulated */
89 ERSPAN_ENCAP_INFRAME = 0x3, /* VLAN tag perserved in frame */
90};
91
92#define ERSPAN_V1_MDSIZE 4
93#define ERSPAN_V2_MDSIZE 8
94
95struct erspan_base_hdr {
96#if defined(__LITTLE_ENDIAN_BITFIELD)
97 __u8 vlan_upper:4,
98 ver:4;
99 __u8 vlan:8;
100 __u8 session_id_upper:2,
101 t:1,
102 en:2,
103 cos:3;
104 __u8 session_id:8;
105#elif defined(__BIG_ENDIAN_BITFIELD)
106 __u8 ver: 4,
107 vlan_upper:4;
108 __u8 vlan:8;
109 __u8 cos:3,
110 en:2,
111 t:1,
112 session_id_upper:2;
113 __u8 session_id:8;
114#else
115#error "Please fix <asm/byteorder.h>"
116#endif
117};
118
119static inline void set_session_id(struct erspan_base_hdr *ershdr, u16 id)
120{
121 ershdr->session_id = id & 0xff;
122 ershdr->session_id_upper = (id >> 8) & 0x3;
123}
124
125static inline u16 get_session_id(const struct erspan_base_hdr *ershdr)
126{
127 return (ershdr->session_id_upper << 8) + ershdr->session_id;
128}
129
130static inline void set_vlan(struct erspan_base_hdr *ershdr, u16 vlan)
131{
132 ershdr->vlan = vlan & 0xff;
133 ershdr->vlan_upper = (vlan >> 8) & 0xf;
134}
135
136static inline u16 get_vlan(const struct erspan_base_hdr *ershdr)
137{
138 return (ershdr->vlan_upper << 8) + ershdr->vlan;
139}
140
141static inline void set_hwid(struct erspan_md2 *md2, u8 hwid)
142{
143 md2->hwid = hwid & 0xf;
144 md2->hwid_upper = (hwid >> 4) & 0x3;
145}
146
147static inline u8 get_hwid(const struct erspan_md2 *md2)
148{
149 return (md2->hwid_upper << 4) + md2->hwid;
150}
151
152static inline int erspan_hdr_len(int version)
153{
154 if (version == 0)
155 return 0;
156
157 return sizeof(struct erspan_base_hdr) +
158 (version == 1 ? ERSPAN_V1_MDSIZE : ERSPAN_V2_MDSIZE);
159}
160
161static inline u8 tos_to_cos(u8 tos)
162{
163 u8 dscp, cos;
164
165 dscp = tos >> 2;
166 cos = dscp >> 3;
167 return cos;
168}
169
170static inline void erspan_build_header(struct sk_buff *skb,
171 u32 id, u32 index,
172 bool truncate, bool is_ipv4)
173{
174 struct ethhdr *eth = (struct ethhdr *)skb->data;
175 enum erspan_encap_type enc_type;
176 struct erspan_base_hdr *ershdr;
177 struct qtag_prefix {
178 __be16 eth_type;
179 __be16 tci;
180 } *qp;
181 u16 vlan_tci = 0;
182 u8 tos;
183 __be32 *idx;
184
185 tos = is_ipv4 ? ip_hdr(skb)->tos :
186 (ipv6_hdr(skb)->priority << 4) +
187 (ipv6_hdr(skb)->flow_lbl[0] >> 4);
188
189 enc_type = ERSPAN_ENCAP_NOVLAN;
190
191 /* If mirrored packet has vlan tag, extract tci and
192 * perserve vlan header in the mirrored frame.
193 */
194 if (eth->h_proto == htons(ETH_P_8021Q)) {
195 qp = (struct qtag_prefix *)(skb->data + 2 * ETH_ALEN);
196 vlan_tci = ntohs(qp->tci);
197 enc_type = ERSPAN_ENCAP_INFRAME;
198 }
199
200 skb_push(skb, sizeof(*ershdr) + ERSPAN_V1_MDSIZE);
201 ershdr = (struct erspan_base_hdr *)skb->data;
202 memset(ershdr, 0, sizeof(*ershdr) + ERSPAN_V1_MDSIZE);
203
204 /* Build base header */
205 ershdr->ver = ERSPAN_VERSION;
206 ershdr->cos = tos_to_cos(tos);
207 ershdr->en = enc_type;
208 ershdr->t = truncate;
209 set_vlan(ershdr, vlan_tci);
210 set_session_id(ershdr, id);
211
212 /* Build metadata */
213 idx = (__be32 *)(ershdr + 1);
214 *idx = htonl(index & INDEX_MASK);
215}
216
217/* ERSPAN GRA: timestamp granularity
218 * 00b --> granularity = 100 microseconds
219 * 01b --> granularity = 100 nanoseconds
220 * 10b --> granularity = IEEE 1588
221 * Here we only support 100 microseconds.
222 */
223static inline __be32 erspan_get_timestamp(void)
224{
225 u64 h_usecs;
226 ktime_t kt;
227
228 kt = ktime_get_real();
229 h_usecs = ktime_divns(kt, 100 * NSEC_PER_USEC);
230
231 /* ERSPAN base header only has 32-bit,
232 * so it wraps around 4 days.
233 */
234 return htonl((u32)h_usecs);
235}
236
237/* ERSPAN BSO (Bad/Short/Oversized), see RFC1757
238 * 00b --> Good frame with no error, or unknown integrity
239 * 01b --> Payload is a Short Frame
240 * 10b --> Payload is an Oversized Frame
241 * 11b --> Payload is a Bad Frame with CRC or Alignment Error
242 */
243enum erspan_bso {
244 BSO_NOERROR = 0x0,
245 BSO_SHORT = 0x1,
246 BSO_OVERSIZED = 0x2,
247 BSO_BAD = 0x3,
248};
249
250static inline u8 erspan_detect_bso(struct sk_buff *skb)
251{
252 /* BSO_BAD is not handled because the frame CRC
253 * or alignment error information is in FCS.
254 */
255 if (skb->len < ETH_ZLEN)
256 return BSO_SHORT;
257
258 if (skb->len > ETH_FRAME_LEN)
259 return BSO_OVERSIZED;
260
261 return BSO_NOERROR;
262}
263
264static inline void erspan_build_header_v2(struct sk_buff *skb,
265 u32 id, u8 direction, u16 hwid,
266 bool truncate, bool is_ipv4)
267{
268 struct ethhdr *eth = (struct ethhdr *)skb->data;
269 struct erspan_base_hdr *ershdr;
270 struct erspan_md2 *md2;
271 struct qtag_prefix {
272 __be16 eth_type;
273 __be16 tci;
274 } *qp;
275 u16 vlan_tci = 0;
276 u8 gra = 0; /* 100 usec */
277 u8 bso = 0; /* Bad/Short/Oversized */
278 u8 sgt = 0;
279 u8 tos;
280
281 tos = is_ipv4 ? ip_hdr(skb)->tos :
282 (ipv6_hdr(skb)->priority << 4) +
283 (ipv6_hdr(skb)->flow_lbl[0] >> 4);
284
285 /* Unlike v1, v2 does not have En field,
286 * so only extract vlan tci field.
287 */
288 if (eth->h_proto == htons(ETH_P_8021Q)) {
289 qp = (struct qtag_prefix *)(skb->data + 2 * ETH_ALEN);
290 vlan_tci = ntohs(qp->tci);
291 }
292
293 bso = erspan_detect_bso(skb);
294 skb_push(skb, sizeof(*ershdr) + ERSPAN_V2_MDSIZE);
295 ershdr = (struct erspan_base_hdr *)skb->data;
296 memset(ershdr, 0, sizeof(*ershdr) + ERSPAN_V2_MDSIZE);
297
298 /* Build base header */
299 ershdr->ver = ERSPAN_VERSION2;
300 ershdr->cos = tos_to_cos(tos);
301 ershdr->en = bso;
302 ershdr->t = truncate;
303 set_vlan(ershdr, vlan_tci);
304 set_session_id(ershdr, id);
305
306 /* Build metadata */
307 md2 = (struct erspan_md2 *)(ershdr + 1);
308 md2->timestamp = erspan_get_timestamp();
309 md2->sgt = htons(sgt);
310 md2->p = 1;
311 md2->ft = 0;
312 md2->dir = direction;
313 md2->gra = gra;
314 md2->o = 0;
315 set_hwid(md2, hwid);
316}
317
318#endif