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#ifndef included_vnet_gre_packet_h
#define included_vnet_gre_packet_h
/*
* GRE packet format
*
* Copyright (c) 2012 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define foreach_gre_protocol \
_ (0x0800, ip4) \
_ (0x86DD, ip6) \
_ (0x6558, teb) \
_ (0x0806, arp) \
_ (0x8847, mpls_unicast) \
_ (0x88BE, erspan) \
_ (0x894F, nsh)
typedef enum
{
#define _(n,f) GRE_PROTOCOL_##f = n,
foreach_gre_protocol
#undef _
} gre_protocol_t;
typedef struct
{
/* flags and version */
u16 flags_and_version;
/* unimplemented at the moment */
#define GRE_FLAGS_CHECKSUM (1 << 15)
/* deprecated, according to rfc2784 */
#define GRE_FLAGS_ROUTING (1 << 14)
#define GRE_FLAGS_KEY (1 << 13)
#define GRE_FLAGS_SEQUENCE (1 << 12)
#define GRE_FLAGS_STRICT_SOURCE_ROUTE (1 << 11)
/* version 1 is PPTP which we don't support */
#define GRE_SUPPORTED_VERSION 0
#define GRE_VERSION_MASK 0x7
/* 0x800 for ip4, etc. */
u16 protocol;
} gre_header_t;
/* From draft-foschiano-erspan-03.txt
Different frame variants known as "ERSPAN Types" can be
distinguished based on the GRE "Protocol Type" field value: Type I
and II's value is 0x88BE while Type III's is 0x22EB [ETYPES].
GRE header for ERSPAN Type 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) may be set to 1. The
other fields are always set to zero.
ERSPAN Type II's frame format also adds a special 8-octet ERSPAN
"feature" header on top of the MAC/IPv4/GRE headers to enclose the
raw mirrored frames.
The ERSPAN Type II feature header is described below:
ERSPAN 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The various fields of the above header are described in this table:
Field Position Length Definition
[octet:bit] (bits)
Ver [42:0] 4 ERSPAN Encapsulation version.
This indicates the version of
the ERSPAN encapsulation
specification. Set to 0x1 for
Type II.
VLAN [42:4] 12 Original VLAN of the frame,
mirrored from the source.
If the En field is set to 11,
the value of VLAN is undefined.
COS [44:0] 3 Original class of service of the
frame, mirrored from the source.
En [44:3] 2 The trunk encapsulation type
associated with the ERSPAN source
port for ingress ERSPAN traffic.
The possible values are:
00-originally without VLAN tag
01-originally ISL encapsulated
10-originally 802.1Q encapsulated
11-VLAN tag preserved in frame.
T [44:5] 1 This bit indicates that the frame
copy encapsulated in the ERSPAN
packet has been truncated. This
occurs if the ERSPAN encapsulated
frame exceeds the configured MTU.
Session ID [44:6] 10 Identification associated with
(ERSPAN ID) each ERSPAN session. Must be
unique between the source and the
receiver(s). (See section below.)
Reserved [46:0] 12 All bits are set to zero
Index [47:4] 20 A 20 bit index/port number
associated with the ERSPAN
traffic's port and
direction (ingress/egress). N.B.:
This field is platform dependent.
*/
typedef CLIB_PACKED (struct {
u32 seq_num;
union
{
struct
{
u16 ver_vlan;
u16 cos_en_t_session;
u32 res_index;
} t2;
u64 t2_u64;
};
}) erspan_t2_t;
typedef CLIB_PACKED (struct {
gre_header_t gre;
erspan_t2_t erspan;
}) erspan_t2_header_t;
/* u64 template for ERSPAN type 2 header with both EN bits set */
#define ERSPAN_HDR2 0x1000180000000000ul
#endif /* included_vnet_gre_packet_h */
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
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