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
85 enum 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
95 struct 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
set_session_id(struct erspan_base_hdr * ershdr,u16 id)119 static 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
get_session_id(const struct erspan_base_hdr * ershdr)125 static inline u16 get_session_id(const struct erspan_base_hdr *ershdr)
126 {
127 return (ershdr->session_id_upper << 8) + ershdr->session_id;
128 }
129
set_vlan(struct erspan_base_hdr * ershdr,u16 vlan)130 static 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
get_vlan(const struct erspan_base_hdr * ershdr)136 static inline u16 get_vlan(const struct erspan_base_hdr *ershdr)
137 {
138 return (ershdr->vlan_upper << 8) + ershdr->vlan;
139 }
140
set_hwid(struct erspan_md2 * md2,u8 hwid)141 static 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
get_hwid(const struct erspan_md2 * md2)147 static inline u8 get_hwid(const struct erspan_md2 *md2)
148 {
149 return (md2->hwid_upper << 4) + md2->hwid;
150 }
151
erspan_hdr_len(int version)152 static 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
tos_to_cos(u8 tos)161 static 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
erspan_build_header(struct sk_buff * skb,u32 id,u32 index,bool truncate,bool is_ipv4)170 static 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 */
erspan_get_timestamp(void)223 static 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 */
243 enum erspan_bso {
244 BSO_NOERROR = 0x0,
245 BSO_SHORT = 0x1,
246 BSO_OVERSIZED = 0x2,
247 BSO_BAD = 0x3,
248 };
249
erspan_detect_bso(struct sk_buff * skb)250 static 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
erspan_build_header_v2(struct sk_buff * skb,u32 id,u8 direction,u16 hwid,bool truncate,bool is_ipv4)264 static 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
319