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f989d546a2
The Type I ERSPAN frame format is based on the barebones
IP + GRE(4-byte) encapsulation on top of the raw mirrored frame.
Both type I and II use 0x88BE as protocol type. Unlike type II
and III, no sequence number or key is required.
To creat a type I erspan tunnel device:
$ ip link add dev erspan11 type erspan \
local 172.16.1.100 remote 172.16.1.200 \
erspan_ver 0
Signed-off-by: William Tu <u9012063@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
319 lines
9.0 KiB
C
319 lines
9.0 KiB
C
#ifndef __LINUX_ERSPAN_H
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#define __LINUX_ERSPAN_H
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/*
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* GRE header for ERSPAN type I encapsulation (4 octets [34:37])
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* 0 1 2 3
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* 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
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* |0|0|0|0|0|00000|000000000|00000| Protocol Type for ERSPAN |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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*
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* The Type I ERSPAN frame format is based on the barebones IP + GRE
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* encapsulation (as described above) on top of the raw mirrored frame.
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* There is no extra ERSPAN header.
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*
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*
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* GRE header for ERSPAN type II and II encapsulation (8 octets [34:41])
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* 0 1 2 3
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* 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
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* |0|0|0|1|0|00000|000000000|00000| Protocol Type for ERSPAN |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | Sequence Number (increments per packet per session) |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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*
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* Note that in the above GRE header [RFC1701] out of the C, R, K, S,
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* s, Recur, Flags, Version fields only S (bit 03) is set to 1. The
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* other fields are set to zero, so only a sequence number follows.
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*
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* ERSPAN Version 1 (Type II) header (8 octets [42:49])
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* 0 1 2 3
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* 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
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | Ver | VLAN | COS | En|T| Session ID |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | Reserved | Index |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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*
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*
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* ERSPAN Version 2 (Type III) header (12 octets [42:49])
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* 0 1 2 3
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* 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
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | Ver | VLAN | COS |BSO|T| Session ID |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | Timestamp |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | SGT |P| FT | Hw ID |D|Gra|O|
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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*
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* Platform Specific SubHeader (8 octets, optional)
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | Platf ID | Platform Specific Info |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | Platform Specific Info |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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*
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* GRE proto ERSPAN type I/II = 0x88BE, type III = 0x22EB
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*/
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#include <uapi/linux/erspan.h>
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#define ERSPAN_VERSION 0x1 /* ERSPAN type II */
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#define VER_MASK 0xf000
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#define VLAN_MASK 0x0fff
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#define COS_MASK 0xe000
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#define EN_MASK 0x1800
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#define T_MASK 0x0400
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#define ID_MASK 0x03ff
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#define INDEX_MASK 0xfffff
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#define ERSPAN_VERSION2 0x2 /* ERSPAN type III*/
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#define BSO_MASK EN_MASK
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#define SGT_MASK 0xffff0000
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#define P_MASK 0x8000
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#define FT_MASK 0x7c00
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#define HWID_MASK 0x03f0
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#define DIR_MASK 0x0008
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#define GRA_MASK 0x0006
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#define O_MASK 0x0001
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#define HWID_OFFSET 4
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#define DIR_OFFSET 3
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enum erspan_encap_type {
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ERSPAN_ENCAP_NOVLAN = 0x0, /* originally without VLAN tag */
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ERSPAN_ENCAP_ISL = 0x1, /* originally ISL encapsulated */
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ERSPAN_ENCAP_8021Q = 0x2, /* originally 802.1Q encapsulated */
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ERSPAN_ENCAP_INFRAME = 0x3, /* VLAN tag perserved in frame */
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};
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#define ERSPAN_V1_MDSIZE 4
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#define ERSPAN_V2_MDSIZE 8
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struct erspan_base_hdr {
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#if defined(__LITTLE_ENDIAN_BITFIELD)
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__u8 vlan_upper:4,
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ver:4;
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__u8 vlan:8;
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__u8 session_id_upper:2,
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t:1,
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en:2,
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cos:3;
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__u8 session_id:8;
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#elif defined(__BIG_ENDIAN_BITFIELD)
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__u8 ver: 4,
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vlan_upper:4;
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__u8 vlan:8;
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__u8 cos:3,
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en:2,
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t:1,
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session_id_upper:2;
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__u8 session_id:8;
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#else
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#error "Please fix <asm/byteorder.h>"
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#endif
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};
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static inline void set_session_id(struct erspan_base_hdr *ershdr, u16 id)
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{
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ershdr->session_id = id & 0xff;
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ershdr->session_id_upper = (id >> 8) & 0x3;
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}
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static inline u16 get_session_id(const struct erspan_base_hdr *ershdr)
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{
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return (ershdr->session_id_upper << 8) + ershdr->session_id;
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}
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static inline void set_vlan(struct erspan_base_hdr *ershdr, u16 vlan)
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{
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ershdr->vlan = vlan & 0xff;
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ershdr->vlan_upper = (vlan >> 8) & 0xf;
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}
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static inline u16 get_vlan(const struct erspan_base_hdr *ershdr)
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{
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return (ershdr->vlan_upper << 8) + ershdr->vlan;
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}
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static inline void set_hwid(struct erspan_md2 *md2, u8 hwid)
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{
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md2->hwid = hwid & 0xf;
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md2->hwid_upper = (hwid >> 4) & 0x3;
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}
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static inline u8 get_hwid(const struct erspan_md2 *md2)
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{
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return (md2->hwid_upper << 4) + md2->hwid;
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}
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static inline int erspan_hdr_len(int version)
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{
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if (version == 0)
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return 0;
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return sizeof(struct erspan_base_hdr) +
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(version == 1 ? ERSPAN_V1_MDSIZE : ERSPAN_V2_MDSIZE);
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}
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static inline u8 tos_to_cos(u8 tos)
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{
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u8 dscp, cos;
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dscp = tos >> 2;
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cos = dscp >> 3;
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return cos;
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}
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static inline void erspan_build_header(struct sk_buff *skb,
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u32 id, u32 index,
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bool truncate, bool is_ipv4)
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{
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struct ethhdr *eth = (struct ethhdr *)skb->data;
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enum erspan_encap_type enc_type;
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struct erspan_base_hdr *ershdr;
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struct qtag_prefix {
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__be16 eth_type;
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__be16 tci;
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} *qp;
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u16 vlan_tci = 0;
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u8 tos;
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__be32 *idx;
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tos = is_ipv4 ? ip_hdr(skb)->tos :
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(ipv6_hdr(skb)->priority << 4) +
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(ipv6_hdr(skb)->flow_lbl[0] >> 4);
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enc_type = ERSPAN_ENCAP_NOVLAN;
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/* If mirrored packet has vlan tag, extract tci and
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* perserve vlan header in the mirrored frame.
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*/
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if (eth->h_proto == htons(ETH_P_8021Q)) {
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qp = (struct qtag_prefix *)(skb->data + 2 * ETH_ALEN);
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vlan_tci = ntohs(qp->tci);
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enc_type = ERSPAN_ENCAP_INFRAME;
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}
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skb_push(skb, sizeof(*ershdr) + ERSPAN_V1_MDSIZE);
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ershdr = (struct erspan_base_hdr *)skb->data;
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memset(ershdr, 0, sizeof(*ershdr) + ERSPAN_V1_MDSIZE);
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/* Build base header */
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ershdr->ver = ERSPAN_VERSION;
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ershdr->cos = tos_to_cos(tos);
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ershdr->en = enc_type;
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ershdr->t = truncate;
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set_vlan(ershdr, vlan_tci);
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set_session_id(ershdr, id);
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/* Build metadata */
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idx = (__be32 *)(ershdr + 1);
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*idx = htonl(index & INDEX_MASK);
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}
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/* ERSPAN GRA: timestamp granularity
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* 00b --> granularity = 100 microseconds
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* 01b --> granularity = 100 nanoseconds
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* 10b --> granularity = IEEE 1588
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* Here we only support 100 microseconds.
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*/
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static inline __be32 erspan_get_timestamp(void)
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{
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u64 h_usecs;
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ktime_t kt;
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kt = ktime_get_real();
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h_usecs = ktime_divns(kt, 100 * NSEC_PER_USEC);
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/* ERSPAN base header only has 32-bit,
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* so it wraps around 4 days.
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*/
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return htonl((u32)h_usecs);
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}
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/* ERSPAN BSO (Bad/Short/Oversized), see RFC1757
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* 00b --> Good frame with no error, or unknown integrity
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* 01b --> Payload is a Short Frame
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* 10b --> Payload is an Oversized Frame
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* 11b --> Payload is a Bad Frame with CRC or Alignment Error
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*/
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enum erspan_bso {
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BSO_NOERROR = 0x0,
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BSO_SHORT = 0x1,
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BSO_OVERSIZED = 0x2,
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BSO_BAD = 0x3,
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};
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static inline u8 erspan_detect_bso(struct sk_buff *skb)
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{
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/* BSO_BAD is not handled because the frame CRC
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* or alignment error information is in FCS.
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*/
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if (skb->len < ETH_ZLEN)
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return BSO_SHORT;
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if (skb->len > ETH_FRAME_LEN)
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return BSO_OVERSIZED;
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return BSO_NOERROR;
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}
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static inline void erspan_build_header_v2(struct sk_buff *skb,
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u32 id, u8 direction, u16 hwid,
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bool truncate, bool is_ipv4)
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{
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struct ethhdr *eth = (struct ethhdr *)skb->data;
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struct erspan_base_hdr *ershdr;
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struct erspan_md2 *md2;
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struct qtag_prefix {
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__be16 eth_type;
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__be16 tci;
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} *qp;
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u16 vlan_tci = 0;
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u8 gra = 0; /* 100 usec */
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u8 bso = 0; /* Bad/Short/Oversized */
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u8 sgt = 0;
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u8 tos;
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tos = is_ipv4 ? ip_hdr(skb)->tos :
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(ipv6_hdr(skb)->priority << 4) +
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(ipv6_hdr(skb)->flow_lbl[0] >> 4);
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/* Unlike v1, v2 does not have En field,
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* so only extract vlan tci field.
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*/
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if (eth->h_proto == htons(ETH_P_8021Q)) {
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qp = (struct qtag_prefix *)(skb->data + 2 * ETH_ALEN);
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vlan_tci = ntohs(qp->tci);
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}
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bso = erspan_detect_bso(skb);
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skb_push(skb, sizeof(*ershdr) + ERSPAN_V2_MDSIZE);
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ershdr = (struct erspan_base_hdr *)skb->data;
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memset(ershdr, 0, sizeof(*ershdr) + ERSPAN_V2_MDSIZE);
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/* Build base header */
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ershdr->ver = ERSPAN_VERSION2;
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ershdr->cos = tos_to_cos(tos);
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ershdr->en = bso;
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ershdr->t = truncate;
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set_vlan(ershdr, vlan_tci);
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set_session_id(ershdr, id);
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/* Build metadata */
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md2 = (struct erspan_md2 *)(ershdr + 1);
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md2->timestamp = erspan_get_timestamp();
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md2->sgt = htons(sgt);
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md2->p = 1;
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md2->ft = 0;
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md2->dir = direction;
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md2->gra = gra;
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md2->o = 0;
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set_hwid(md2, hwid);
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}
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#endif
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