LXR linux/include/net/erspan.h

   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
  73enum 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
  83struct 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
 107static 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
 113static inline u16 get_session_id(const struct erspan_base_hdr *ershdr)
 114{
 115        return (ershdr->session_id_upper << 8) + ershdr->session_id;
 116}
 117
 118static 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
 124static inline u16 get_vlan(const struct erspan_base_hdr *ershdr)
 125{
 126        return (ershdr->vlan_upper << 8) + ershdr->vlan;
 127}
 128
 129static 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
 135static inline u8 get_hwid(const struct erspan_md2 *md2)
 136{
 137        return (md2->hwid_upper << 4) + md2->hwid;
 138}
 139
 140static 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
 146static 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
 155static 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 */
 208static 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 */
 228enum erspan_bso {
 229        BSO_NOERROR = 0x0,
 230        BSO_SHORT = 0x1,
 231        BSO_OVERSIZED = 0x2,
 232        BSO_BAD = 0x3,
 233};
 234
 235static 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
 249static 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