LXR linux/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
  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
 319