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linux/include/net/erspan.h
William Tu f551c91de2 net: erspan: introduce erspan v2 for ip_gre 
The patch adds support for erspan version 2.  Not all features are
supported in this patch.  The SGT (security group tag), GRA (timestamp
granularity), FT (frame type) are set to fixed value.  Only hardware
ID and direction are configurable.  Optional subheader is also not
supported.

Signed-off-by: William Tu <u9012063@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-12-15 12:34:00 -05:00

243 lines
7.4 KiB
C
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#ifndef __LINUX_ERSPAN_H
#define __LINUX_ERSPAN_H
/*
* GRE header for ERSPAN encapsulation (8 octets [34:41]) -- 8 bytes
* 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 II = 0x88BE, type III = 0x22EB
*/
#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
/* ERSPAN version 2 metadata header */
struct erspan_md2 {
__be32 timestamp;
__be16 sgt; /* security group tag */
__be16 flags;
#define P_OFFSET 15
#define FT_OFFSET 10
#define HWID_OFFSET 4
#define DIR_OFFSET 3
#define GRA_OFFSET 1
};
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 perserved in frame */
};
#define ERSPAN_V1_MDSIZE 4
#define ERSPAN_V2_MDSIZE 8
struct erspan_metadata {
union {
__be32 index; /* Version 1 (type II)*/
struct erspan_md2 md2; /* Version 2 (type III) */
} u;
int version;
};
struct erspan_base_hdr {
__be16 ver_vlan;
#define VER_OFFSET 12
__be16 session_id;
#define COS_OFFSET 13
#define EN_OFFSET 11
#define BSO_OFFSET EN_OFFSET
#define T_OFFSET 10
};
static inline int erspan_hdr_len(int version)
{
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,
__be32 id, u32 index,
bool truncate, bool is_ipv4)
{
struct ethhdr *eth = eth_hdr(skb);
enum erspan_encap_type enc_type;
struct erspan_base_hdr *ershdr;
struct erspan_metadata *ersmd;
struct qtag_prefix {
__be16 eth_type;
__be16 tci;
} *qp;
u16 vlan_tci = 0;
u8 tos;
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
* perserve 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_vlan = htons((vlan_tci & VLAN_MASK) |
(ERSPAN_VERSION << VER_OFFSET));
ershdr->session_id = htons((u16)(ntohl(id) & ID_MASK) |
((tos_to_cos(tos) << COS_OFFSET) & COS_MASK) |
(enc_type << EN_OFFSET & EN_MASK) |
((truncate << T_OFFSET) & T_MASK));
/* Build metadata */
ersmd = (struct erspan_metadata *)(ershdr + 1);
ersmd->u.index = 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);
}
static inline void erspan_build_header_v2(struct sk_buff *skb,
__be32 id, u8 direction, u16 hwid,
bool truncate, bool is_ipv4)
{
struct ethhdr *eth = eth_hdr(skb);
struct erspan_base_hdr *ershdr;
struct erspan_metadata *md;
struct qtag_prefix {
__be16 eth_type;
__be16 tci;
} *qp;
u16 vlan_tci = 0;
u16 session_id;
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);
}
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_vlan = htons((vlan_tci & VLAN_MASK) |
(ERSPAN_VERSION2 << VER_OFFSET));
session_id = (u16)(ntohl(id) & ID_MASK) |
((tos_to_cos(tos) << COS_OFFSET) & COS_MASK) |
(bso << BSO_OFFSET & BSO_MASK) |
((truncate << T_OFFSET) & T_MASK);
ershdr->session_id = htons(session_id);
/* Build metadata */
md = (struct erspan_metadata *)(ershdr + 1);
md->u.md2.timestamp = erspan_get_timestamp();
md->u.md2.sgt = htons(sgt);
md->u.md2.flags = htons(((1 << P_OFFSET) & P_MASK) |
((hwid << HWID_OFFSET) & HWID_MASK) |
((direction << DIR_OFFSET) & DIR_MASK) |
((gra << GRA_OFFSET) & GRA_MASK));
}
#endif
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