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TOMOYO Linux Cross Reference
Linux/include/net/erspan.h

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

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