243 lines
7.4 KiB
C
243 lines
7.4 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 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 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 II = 0x88BE, type III = 0x22EB
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*/
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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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/* ERSPAN version 2 metadata header */
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struct erspan_md2 {
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__be32 timestamp;
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__be16 sgt; /* security group tag */
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__be16 flags;
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#define P_OFFSET 15
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#define FT_OFFSET 10
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#define HWID_OFFSET 4
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#define DIR_OFFSET 3
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#define GRA_OFFSET 1
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};
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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_metadata {
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union {
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__be32 index; /* Version 1 (type II)*/
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struct erspan_md2 md2; /* Version 2 (type III) */
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} u;
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int version;
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};
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struct erspan_base_hdr {
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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 BSO_OFFSET EN_OFFSET
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#define T_OFFSET 10
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};
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static inline int erspan_hdr_len(int version)
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{
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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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__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 erspan_base_hdr *ershdr;
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struct erspan_metadata *ersmd;
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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) + 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_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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/* Build metadata */
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ersmd = (struct erspan_metadata *)(ershdr + 1);
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ersmd->u.index = 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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static inline void erspan_build_header_v2(struct sk_buff *skb,
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__be32 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 = eth_hdr(skb);
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struct erspan_base_hdr *ershdr;
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struct erspan_metadata *md;
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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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u16 session_id;
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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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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_vlan = htons((vlan_tci & VLAN_MASK) |
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(ERSPAN_VERSION2 << VER_OFFSET));
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session_id = (u16)(ntohl(id) & ID_MASK) |
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((tos_to_cos(tos) << COS_OFFSET) & COS_MASK) |
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(bso << BSO_OFFSET & BSO_MASK) |
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((truncate << T_OFFSET) & T_MASK);
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ershdr->session_id = htons(session_id);
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/* Build metadata */
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md = (struct erspan_metadata *)(ershdr + 1);
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md->u.md2.timestamp = erspan_get_timestamp();
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md->u.md2.sgt = htons(sgt);
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md->u.md2.flags = htons(((1 << P_OFFSET) & P_MASK) |
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((hwid << HWID_OFFSET) & HWID_MASK) |
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((direction << DIR_OFFSET) & DIR_MASK) |
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((gra << GRA_OFFSET) & GRA_MASK));
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}
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#endif
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