2017-08-23 00:40:28 +08:00
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#ifndef __LINUX_ERSPAN_H
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#define __LINUX_ERSPAN_H
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/*
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* GRE header for ERSPAN encapsulation (8 octets [34:41]) -- 8 bytes
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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 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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* GRE proto ERSPAN type II = 0x88BE, type III = 0x22EB
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*/
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#define ERSPAN_VERSION 0x1
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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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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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struct erspan_metadata {
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__be32 index; /* type II */
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};
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struct erspanhdr {
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__be16 ver_vlan;
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#define VER_OFFSET 12
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__be16 session_id;
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#define COS_OFFSET 13
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#define EN_OFFSET 11
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#define T_OFFSET 10
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struct erspan_metadata md;
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};
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2017-12-01 03:51:27 +08:00
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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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__be32 id, u32 index,
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bool truncate, bool is_ipv4)
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{
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struct ethhdr *eth = eth_hdr(skb);
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enum erspan_encap_type enc_type;
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struct erspanhdr *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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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));
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ershdr = (struct erspanhdr *)skb->data;
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memset(ershdr, 0, sizeof(*ershdr));
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ershdr->ver_vlan = htons((vlan_tci & VLAN_MASK) |
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(ERSPAN_VERSION << VER_OFFSET));
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ershdr->session_id = htons((u16)(ntohl(id) & ID_MASK) |
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((tos_to_cos(tos) << COS_OFFSET) & COS_MASK) |
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(enc_type << EN_OFFSET & EN_MASK) |
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((truncate << T_OFFSET) & T_MASK));
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ershdr->md.index = htonl(index & INDEX_MASK);
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}
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2017-08-23 00:40:28 +08:00
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#endif
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