#ifndef __LINUX_ERSPAN_H#define __LINUX_ERSPAN_H /* * GRE header for ERSPAN type I encapsulation (4 octets [34:37]) * 0 1 2 3 * 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 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * |0|0|0|0|0|00000|000000000|00000| Protocol Type for ERSPAN | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * * The Type I ERSPAN frame format is based on the barebones IP + GRE * encapsulation (as described above) on top of the raw mirrored frame. * There is no extra ERSPAN header. * * * GRE header for ERSPAN type II and II encapsulation (8 octets [34:41]) * 0 1 2 3 * 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 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * |0|0|0|1|0|00000|000000000|00000| Protocol Type for ERSPAN | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Sequence Number (increments per packet per session) | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * * Note that in the above GRE header [RFC1701] out of the C, R, K, S, * s, Recur, Flags, Version fields only S (bit 03) is set to 1. The * other fields are set to zero, so only a sequence number follows. * * ERSPAN Version 1 (Type II) header (8 octets [42:49]) * 0 1 2 3 * 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 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Ver | VLAN | COS | En|T| Session ID | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Reserved | Index | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * * * ERSPAN Version 2 (Type III) header (12 octets [42:49]) * 0 1 2 3 * 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 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Ver | VLAN | COS |BSO|T| Session ID | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Timestamp | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | SGT |P| FT | Hw ID |D|Gra|O| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * * Platform Specific SubHeader (8 octets, optional) * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Platf ID | Platform Specific Info | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * | Platform Specific Info | * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ * * GRE proto ERSPAN type I/II = 0x88BE, type III = 0x22EB */ #include <linux/ip.h>#include <linux/ipv6.h>#include <linux/skbuff.h>#include <uapi/linux/erspan.h> #define ERSPAN_VERSION 0x1 /* ERSPAN type II */#define VER_MASK 0xf000#define VLAN_MASK 0x0fff#define COS_MASK 0xe000#define EN_MASK 0x1800#define T_MASK 0x0400#define ID_MASK 0x03ff#define INDEX_MASK 0xfffff #define ERSPAN_VERSION2 0x2 /* ERSPAN type III*/#define BSO_MASK EN_MASK#define SGT_MASK 0xffff0000#define P_MASK 0x8000#define FT_MASK 0x7c00#define HWID_MASK 0x03f0#define DIR_MASK 0x0008#define GRA_MASK 0x0006#define O_MASK 0x0001 #define HWID_OFFSET 4#define DIR_OFFSET 3 enum erspan_encap_type { ERSPAN_ENCAP_NOVLAN = 0x0, /* originally without VLAN tag */ ERSPAN_ENCAP_ISL = 0x1, /* originally ISL encapsulated */ ERSPAN_ENCAP_8021Q = 0x2, /* originally 802.1Q encapsulated */ ERSPAN_ENCAP_INFRAME = 0x3, /* VLAN tag preserved in frame */}; #define ERSPAN_V1_MDSIZE 4#define ERSPAN_V2_MDSIZE 8 struct erspan_base_hdr {#if defined(__LITTLE_ENDIAN_BITFIELD) __u8 vlan_upper:4, ver:4; __u8 vlan:8; __u8 session_id_upper:2, t:1, en:2, cos:3; __u8 session_id:8;#elif defined(__BIG_ENDIAN_BITFIELD) __u8 ver: 4, vlan_upper:4; __u8 vlan:8; __u8 cos:3, en:2, t:1, session_id_upper:2; __u8 session_id:8;#else#error "Please fix <asm/byteorder.h>"#endif}; static inline void set_session_id(struct erspan_base_hdr *ershdr, u16 id){ ershdr->session_id = id & 0xff; ershdr->session_id_upper = (id >> 8) & 0x3;} static inline u16 get_session_id(const struct erspan_base_hdr *ershdr){ return (ershdr->session_id_upper << 8) + ershdr->session_id;} static inline void set_vlan(struct erspan_base_hdr *ershdr, u16 vlan){ ershdr->vlan = vlan & 0xff; ershdr->vlan_upper = (vlan >> 8) & 0xf;} static inline u16 get_vlan(const struct erspan_base_hdr *ershdr){ return (ershdr->vlan_upper << 8) + ershdr->vlan;} static inline void set_hwid(struct erspan_md2 *md2, u8 hwid){ md2->hwid = hwid & 0xf; md2->hwid_upper = (hwid >> 4) & 0x3;} static inline u8 get_hwid(const struct erspan_md2 *md2){ return (md2->hwid_upper << 4) + md2->hwid;} static inline int erspan_hdr_len(int version){ if (version == 0) return 0; return sizeof(struct erspan_base_hdr) + (version == 1 ? ERSPAN_V1_MDSIZE : ERSPAN_V2_MDSIZE);} static inline u8 tos_to_cos(u8 tos){ u8 dscp, cos; dscp = tos >> 2; cos = dscp >> 3; return cos;} static inline void erspan_build_header(struct sk_buff *skb, u32 id, u32 index, bool truncate, bool is_ipv4){ struct ethhdr *eth = (struct ethhdr *)skb->data; enum erspan_encap_type enc_type; struct erspan_base_hdr *ershdr; struct qtag_prefix { __be16 eth_type; __be16 tci; } *qp; u16 vlan_tci = 0; u8 tos; __be32 *idx; tos = is_ipv4 ? ip_hdr(skb)->tos : (ipv6_hdr(skb)->priority << 4) + (ipv6_hdr(skb)->flow_lbl[0] >> 4); enc_type = ERSPAN_ENCAP_NOVLAN; /* If mirrored packet has vlan tag, extract tci and * preserve vlan header in the mirrored frame. */ if (eth->h_proto == htons(ETH_P_8021Q)) { qp = (struct qtag_prefix *)(skb->data + 2 * ETH_ALEN); vlan_tci = ntohs(qp->tci); enc_type = ERSPAN_ENCAP_INFRAME; } skb_push(skb, sizeof(*ershdr) + ERSPAN_V1_MDSIZE); ershdr = (struct erspan_base_hdr *)skb->data; memset(ershdr, 0, sizeof(*ershdr) + ERSPAN_V1_MDSIZE); /* Build base header */ ershdr->ver = ERSPAN_VERSION; ershdr->cos = tos_to_cos(tos); ershdr->en = enc_type; ershdr->t = truncate; set_vlan(ershdr, vlan_tci); set_session_id(ershdr, id); /* Build metadata */ idx = (__be32 *)(ershdr + 1); *idx = htonl(index & INDEX_MASK);} /* ERSPAN GRA: timestamp granularity * 00b --> granularity = 100 microseconds * 01b --> granularity = 100 nanoseconds * 10b --> granularity = IEEE 1588 * Here we only support 100 microseconds. */static inline __be32 erspan_get_timestamp(void){ u64 h_usecs; ktime_t kt; kt = ktime_get_real(); h_usecs = ktime_divns(kt, 100 * NSEC_PER_USEC); /* ERSPAN base header only has 32-bit, * so it wraps around 4 days. */ return htonl((u32)h_usecs);} /* ERSPAN BSO (Bad/Short/Oversized), see RFC1757 * 00b --> Good frame with no error, or unknown integrity * 01b --> Payload is a Short Frame * 10b --> Payload is an Oversized Frame * 11b --> Payload is a Bad Frame with CRC or Alignment Error */enum erspan_bso { BSO_NOERROR = 0x0, BSO_SHORT = 0x1, BSO_OVERSIZED = 0x2, BSO_BAD = 0x3,}; static inline u8 erspan_detect_bso(struct sk_buff *skb){ /* BSO_BAD is not handled because the frame CRC * or alignment error information is in FCS. */ if (skb->len < ETH_ZLEN) return BSO_SHORT; if (skb->len > ETH_FRAME_LEN) return BSO_OVERSIZED; return BSO_NOERROR;} static inline void erspan_build_header_v2(struct sk_buff *skb, u32 id, u8 direction, u16 hwid, bool truncate, bool is_ipv4){ struct ethhdr *eth = (struct ethhdr *)skb->data; struct erspan_base_hdr *ershdr; struct erspan_md2 *md2; struct qtag_prefix { __be16 eth_type; __be16 tci; } *qp; u16 vlan_tci = 0; u8 gra = 0; /* 100 usec */ u8 bso = 0; /* Bad/Short/Oversized */ u8 sgt = 0; u8 tos; tos = is_ipv4 ? ip_hdr(skb)->tos : (ipv6_hdr(skb)->priority << 4) + (ipv6_hdr(skb)->flow_lbl[0] >> 4); /* Unlike v1, v2 does not have En field, * so only extract vlan tci field. */ if (eth->h_proto == htons(ETH_P_8021Q)) { qp = (struct qtag_prefix *)(skb->data + 2 * ETH_ALEN); vlan_tci = ntohs(qp->tci); } bso = erspan_detect_bso(skb); skb_push(skb, sizeof(*ershdr) + ERSPAN_V2_MDSIZE); ershdr = (struct erspan_base_hdr *)skb->data; memset(ershdr, 0, sizeof(*ershdr) + ERSPAN_V2_MDSIZE); /* Build base header */ ershdr->ver = ERSPAN_VERSION2; ershdr->cos = tos_to_cos(tos); ershdr->en = bso; ershdr->t = truncate; set_vlan(ershdr, vlan_tci); set_session_id(ershdr, id); /* Build metadata */ md2 = (struct erspan_md2 *)(ershdr + 1); md2->timestamp = erspan_get_timestamp(); md2->sgt = htons(sgt); md2->p = 1; md2->ft = 0; md2->dir = direction; md2->gra = gra; md2->o = 0; set_hwid(md2, hwid);} #endif
#ifndef __LINUX_ERSPAN_H
#define __LINUX_ERSPAN_H
/*
* GRE header for ERSPAN type I encapsulation (4 octets [34:37])
* 0 1 2 3
* 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
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |0|0|0|0|0|00000|000000000|00000| Protocol Type for ERSPAN |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* The Type I ERSPAN frame format is based on the barebones IP + GRE
* encapsulation (as described above) on top of the raw mirrored frame.
* There is no extra ERSPAN header.
*
*
* GRE header for ERSPAN type II and II encapsulation (8 octets [34:41])
* 0 1 2 3
* 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
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |0|0|0|1|0|00000|000000000|00000| Protocol Type for ERSPAN |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Sequence Number (increments per packet per session) |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* Note that in the above GRE header [RFC1701] out of the C, R, K, S,
* s, Recur, Flags, Version fields only S (bit 03) is set to 1. The
* other fields are set to zero, so only a sequence number follows.
*
* ERSPAN Version 1 (Type II) header (8 octets [42:49])
* 0 1 2 3
* 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
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Ver | VLAN | COS | En|T| Session ID |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Reserved | Index |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
*
* ERSPAN Version 2 (Type III) header (12 octets [42:49])
* 0 1 2 3
* 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
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Ver | VLAN | COS |BSO|T| Session ID |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Timestamp |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | SGT |P| FT | Hw ID |D|Gra|O|
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* Platform Specific SubHeader (8 octets, optional)
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Platf ID | Platform Specific Info |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Platform Specific Info |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* GRE proto ERSPAN type I/II = 0x88BE, type III = 0x22EB
*/
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/skbuff.h>
#include <uapi/linux/erspan.h>
#define ERSPAN_VERSION 0x1 /* ERSPAN type II */
#define VER_MASK 0xf000
#define VLAN_MASK 0x0fff
#define COS_MASK 0xe000
#define EN_MASK 0x1800
#define T_MASK 0x0400
#define ID_MASK 0x03ff
#define INDEX_MASK 0xfffff
#define ERSPAN_VERSION2 0x2 /* ERSPAN type III*/
#define BSO_MASK EN_MASK
#define SGT_MASK 0xffff0000
#define P_MASK 0x8000
#define FT_MASK 0x7c00
#define HWID_MASK 0x03f0
#define DIR_MASK 0x0008
#define GRA_MASK 0x0006
#define O_MASK 0x0001
#define HWID_OFFSET 4
#define DIR_OFFSET 3
enum erspan_encap_type {
ERSPAN_ENCAP_NOVLAN = 0x0, /* originally without VLAN tag */
ERSPAN_ENCAP_ISL = 0x1, /* originally ISL encapsulated */
ERSPAN_ENCAP_8021Q = 0x2, /* originally 802.1Q encapsulated */
ERSPAN_ENCAP_INFRAME = 0x3, /* VLAN tag preserved in frame */
};
#define ERSPAN_V1_MDSIZE 4
#define ERSPAN_V2_MDSIZE 8
struct erspan_base_hdr {
#if defined(__LITTLE_ENDIAN_BITFIELD)
__u8 vlan_upper:4,
ver:4;
__u8 vlan:8;
__u8 session_id_upper:2,
t:1,
en:2,
cos:3;
__u8 session_id:8;
#elif defined(__BIG_ENDIAN_BITFIELD)
__u8 ver: 4,
vlan_upper:4;
__u8 vlan:8;
__u8 cos:3,
en:2,
t:1,
session_id_upper:2;
__u8 session_id:8;
#else
#error "Please fix <asm/byteorder.h>"
#endif
};
static inline void set_session_id(struct erspan_base_hdr *ershdr, u16 id)
{
ershdr->session_id = id & 0xff;
ershdr->session_id_upper = (id >> 8) & 0x3;
}
static inline u16 get_session_id(const struct erspan_base_hdr *ershdr)
{
return (ershdr->session_id_upper << 8) + ershdr->session_id;
}
static inline void set_vlan(struct erspan_base_hdr *ershdr, u16 vlan)
{
ershdr->vlan = vlan & 0xff;
ershdr->vlan_upper = (vlan >> 8) & 0xf;
}
static inline u16 get_vlan(const struct erspan_base_hdr *ershdr)
{
return (ershdr->vlan_upper << 8) + ershdr->vlan;
}
static inline void set_hwid(struct erspan_md2 *md2, u8 hwid)
{
md2->hwid = hwid & 0xf;
md2->hwid_upper = (hwid >> 4) & 0x3;
}
static inline u8 get_hwid(const struct erspan_md2 *md2)
{
return (md2->hwid_upper << 4) + md2->hwid;
}
static inline int erspan_hdr_len(int version)
{
if (version == 0)
return 0;
return sizeof(struct erspan_base_hdr) +
(version == 1 ? ERSPAN_V1_MDSIZE : ERSPAN_V2_MDSIZE);
}
static inline u8 tos_to_cos(u8 tos)
{
u8 dscp, cos;
dscp = tos >> 2;
cos = dscp >> 3;
return cos;
}
static inline void erspan_build_header(struct sk_buff *skb,
u32 id, u32 index,
bool truncate, bool is_ipv4)
{
struct ethhdr *eth = (struct ethhdr *)skb->data;
enum erspan_encap_type enc_type;
struct erspan_base_hdr *ershdr;
struct qtag_prefix {
__be16 eth_type;
__be16 tci;
} *qp;
u16 vlan_tci = 0;
u8 tos;
__be32 *idx;
tos = is_ipv4 ? ip_hdr(skb)->tos :
(ipv6_hdr(skb)->priority << 4) +
(ipv6_hdr(skb)->flow_lbl[0] >> 4);
enc_type = ERSPAN_ENCAP_NOVLAN;
/* If mirrored packet has vlan tag, extract tci and
* preserve vlan header in the mirrored frame.
*/
if (eth->h_proto == htons(ETH_P_8021Q)) {
qp = (struct qtag_prefix *)(skb->data + 2 * ETH_ALEN);
vlan_tci = ntohs(qp->tci);
enc_type = ERSPAN_ENCAP_INFRAME;
}
skb_push(skb, sizeof(*ershdr) + ERSPAN_V1_MDSIZE);
ershdr = (struct erspan_base_hdr *)skb->data;
memset(ershdr, 0, sizeof(*ershdr) + ERSPAN_V1_MDSIZE);
/* Build base header */
ershdr->ver = ERSPAN_VERSION;
ershdr->cos = tos_to_cos(tos);
ershdr->en = enc_type;
ershdr->t = truncate;
set_vlan(ershdr, vlan_tci);
set_session_id(ershdr, id);
/* Build metadata */
idx = (__be32 *)(ershdr + 1);
*idx = htonl(index & INDEX_MASK);
}
/* ERSPAN GRA: timestamp granularity
* 00b --> granularity = 100 microseconds
* 01b --> granularity = 100 nanoseconds
* 10b --> granularity = IEEE 1588
* Here we only support 100 microseconds.
*/
static inline __be32 erspan_get_timestamp(void)
{
u64 h_usecs;
ktime_t kt;
kt = ktime_get_real();
h_usecs = ktime_divns(kt, 100 * NSEC_PER_USEC);
/* ERSPAN base header only has 32-bit,
* so it wraps around 4 days.
*/
return htonl((u32)h_usecs);
}
/* ERSPAN BSO (Bad/Short/Oversized), see RFC1757
* 00b --> Good frame with no error, or unknown integrity
* 01b --> Payload is a Short Frame
* 10b --> Payload is an Oversized Frame
* 11b --> Payload is a Bad Frame with CRC or Alignment Error
*/
enum erspan_bso {
BSO_NOERROR = 0x0,
BSO_SHORT = 0x1,
BSO_OVERSIZED = 0x2,
BSO_BAD = 0x3,
};
static inline u8 erspan_detect_bso(struct sk_buff *skb)
{
/* BSO_BAD is not handled because the frame CRC
* or alignment error information is in FCS.
*/
if (skb->len < ETH_ZLEN)
return BSO_SHORT;
if (skb->len > ETH_FRAME_LEN)
return BSO_OVERSIZED;
return BSO_NOERROR;
}
static inline void erspan_build_header_v2(struct sk_buff *skb,
u32 id, u8 direction, u16 hwid,
bool truncate, bool is_ipv4)
{
struct ethhdr *eth = (struct ethhdr *)skb->data;
struct erspan_base_hdr *ershdr;
struct erspan_md2 *md2;
struct qtag_prefix {
__be16 eth_type;
__be16 tci;
} *qp;
u16 vlan_tci = 0;
u8 gra = 0; /* 100 usec */
u8 bso = 0; /* Bad/Short/Oversized */
u8 sgt = 0;
u8 tos;
tos = is_ipv4 ? ip_hdr(skb)->tos :
(ipv6_hdr(skb)->priority << 4) +
(ipv6_hdr(skb)->flow_lbl[0] >> 4);
/* Unlike v1, v2 does not have En field,
* so only extract vlan tci field.
*/
if (eth->h_proto == htons(ETH_P_8021Q)) {
qp = (struct qtag_prefix *)(skb->data + 2 * ETH_ALEN);
vlan_tci = ntohs(qp->tci);
}
bso = erspan_detect_bso(skb);
skb_push(skb, sizeof(*ershdr) + ERSPAN_V2_MDSIZE);
ershdr = (struct erspan_base_hdr *)skb->data;
memset(ershdr, 0, sizeof(*ershdr) + ERSPAN_V2_MDSIZE);
/* Build base header */
ershdr->ver = ERSPAN_VERSION2;
ershdr->cos = tos_to_cos(tos);
ershdr->en = bso;
ershdr->t = truncate;
set_vlan(ershdr, vlan_tci);
set_session_id(ershdr, id);
/* Build metadata */
md2 = (struct erspan_md2 *)(ershdr + 1);
md2->timestamp = erspan_get_timestamp();
md2->sgt = htons(sgt);
md2->p = 1;
md2->ft = 0;
md2->dir = direction;
md2->gra = gra;
md2->o = 0;
set_hwid(md2, hwid);
}
#endif