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/*
* Copyright (c) 2015 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.
*/
#ifndef included_nsh_packet_h
#define included_nsh_packet_h
/*
* NSH packet format from draft-quinn-sfc-nsh-03.txt
*
* NSH Base Header
* 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|O|C| TTL | Length | MD Type | Next Protocol |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
*
* Base Header Field Descriptions:
*
* Version: The version field is used to ensure backward compatibility
* going forward with future NSH updates.
*
* O bit: Indicates that this packet is an operations and management
* (OAM) packet. SFF and SFs nodes MUST examine the payload and take
* appropriate action (e.g. return status information).
*
* OAM message specifics and handling details are outside the scope of
* this document.
*
* C bit: Indicates that a critical metadata TLV is present (see section
* 7). This bit acts as an indication for hardware implementers to
* decide how to handle the presence of a critical TLV without
* necessarily needing to parse all TLVs present. The C bit MUST be set
* to 1 if one or more critical TLVs are present.
*
* All other flag fields are reserved.
*
* Length: total length, in 4 byte words, of the NSH header, including
* optional variable TLVs. Length must be equal or greater than 6.
*
* MD Type: indicates the format of NSH beyond the base header and the
* type of metadata being carried. This typing is used to describe the
* use for the metadata. A new registry will be requested from IANA for
* the MD Type. NSH defines one type, type = 0x1 which indicates that
* the format of the header is as per this draft.
*
* The format of the base header is invariant, and not described by MD
* Type.
*
* Next Protocol: indicates the protocol type of the original packet. A
* new IANA registry will be created for protocol type.
*
* This draft defines the following Next Protocol values:
*
* 0x1 : IPv4
* 0x2 : IPv6
* 0x3 : Ethernet
*/
typedef CLIB_PACKED(struct {
u8 ver_o_c; //TTL: high 4 bit
u8 length; //TTL: low 2 bit
u8 md_type;
u8 next_protocol;
u32 nsp_nsi; // nsp 24 bits, nsi 8 bits
}) nsh_base_header_t;
typedef CLIB_PACKED(struct {
/* Context headers, always present */
u32 c1;
u32 c2;
u32 c3;
u32 c4;
}) nsh_md1_data_t;
typedef CLIB_PACKED(struct {
u16 class;
u8 type;
u8 length;
}) nsh_tlv_header_t;
typedef nsh_tlv_header_t nsh_md2_data_t;
typedef CLIB_PACKED(struct {
nsh_base_header_t nsh_base;
union {
nsh_md1_data_t md1_data;
nsh_md2_data_t md2_data;
} md;
}) nsh_header_t;
#define NSH_VERSION (0<<6)
#define NSH_O_BIT (1<<5)
#define NSH_C_BIT (1<<4)
#define NSH_TTL_H4_MASK 0xF
#define NSH_TTL_L2_MASK 0xC0
#define NSH_LEN_MASK 0x3F
/* Network byte order shift / mask */
#define NSH_NSI_MASK 0xFF
#define NSH_NSP_MASK (0x00FFFFFF)
#define NSH_NSP_SHIFT 8
#endif /* included_nsh_packet_h */
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