include/net/erspan.h

   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
 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
 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
 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
 136 static inline u16 get_vlan(const struct erspan_base_hdr *ershdr)
 137 {
 138         return (ershdr->vlan_upper << 8) + ershdr->vlan;
 139 }
 140
 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
 147 static inline u8 get_hwid(const struct erspan_md2 *md2)
 148 {
 149         return (md2->hwid_upper << 4) + md2->hwid;
 150 }
 151
 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
 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
 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  */
 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
 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
 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