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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 <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 preserved 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 * preserve 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