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#ifndef included_vnet_sr_packet_h
#define included_vnet_sr_packet_h
#include <vnet/ip/ip.h>
/*
* ipv6 segment-routing header format
*
* Copyright (c) 2013 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.
*/
/**
* @file
* @brief The Segment Routing Header (SRH).
*
* The Segment Routing Header (SRH) is defined in the diagram below.
*
*
* 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
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Next Header | Hdr Ext Len | Routing Type | Segments Left |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | First Segment | Flags | HMAC Key ID |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | |
* | Segment List[0] (128 bits ipv6 address) |
* | |
* | |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | |
* | |
* ...
* | |
* | |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | |
* | Segment List[n] (128 bits ipv6 address) |
* | |
* | |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | |
* | Policy List[0] (optional) |
* | |
* | |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | |
* | Policy List[1] (optional) |
* | |
* | |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | |
* | Policy List[2] (optional) |
* | |
* | |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | |
* | |
* | |
* | HMAC (256 bits) |
* | (optional) |
* | |
* | |
* | |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* where:
*
* o Next Header: 8-bit selector. Identifies the type of header
* immediately following the SRH.
*
* o Hdr Ext Len: 8-bit unsigned integer, is the length of the SRH
* header in 8-octet units, not including the first 8 octets.
*
* o Routing Type: TBD, to be assigned by IANA (suggested value: 4).
*
* o Segments Left. Defined in [RFC2460], it contains the index, in
* the Segment List, of the next segment to inspect. Segments Left
* is decremented at each segment and it is used as an index in the
* segment list.
*
* o First Segment: offset in the SRH, not including the first 8 octets
* and expressed in 16-octet units, pointing to the last element of
* the segment list, which is in fact the first segment of the
* segment routing path.
*
* o Flags: 16 bits of flags. Following flags are defined:
*
* 1
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |C|P|R|R| Policy Flags |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*
* C-flag: Clean-up flag. Set when the SRH has to be removed from
* the packet when packet reaches the last segment.
*
* P-flag: Protected flag. Set when the packet has been rerouted
* through FRR mechanism by a SR endpoint node. See Section 6.3
* for more details.
*
* R-flags. Reserved and for future use.
*
* Policy Flags. Define the type of the IPv6 addresses encoded
* into the Policy List (see below). The following have been
* defined:
*
* Bits 4-6: determine the type of the first element after the
* segment list.
*
* Bits 7-9: determine the type of the second element.
*
* Bits 10-12: determine the type of the third element.
*
* Bits 13-15: determine the type of the fourth element.
*
* The following values are used for the type:
*
* 0x0: Not present. If value is set to 0x0, it means the
* element represented by these bits is not present.
*
* 0x1: SR Ingress.
*
* 0x2: SR Egress.
*
* 0x3: Original Source Address.
*
* o HMAC Key ID and HMAC field, and their use are defined in
* [I-D.vyncke-6man-segment-routing-security].
*
* o Segment List[n]: 128 bit IPv6 addresses representing the nth
* segment in the Segment List. The Segment List is encoded starting
* from the last segment of the path. I.e., the first element of the
* segment list (Segment List [0]) contains the last segment of the
* path while the last segment of the Segment List (Segment List[n])
* contains the first segment of the path. The index contained in
* "Segments Left" identifies the current active segment.
*
* o Policy List. Optional addresses representing specific nodes in
* the SR path such as:
*
* SR Ingress: a 128 bit generic identifier representing the
* ingress in the SR domain (i.e.: it needs not to be a valid IPv6
* address).
*
* SR Egress: a 128 bit generic identifier representing the egress
* in the SR domain (i.e.: it needs not to be a valid IPv6
* address).
*
* Original Source Address: IPv6 address originally present in the
* SA field of the packet.
*
* The segments in the Policy List are encoded after the segment list
* and they are optional. If none are in the SRH, all bits of the
* Policy List Flags MUST be set to 0x0.
*/
#ifndef IPPROTO_IPV6_ROUTE
#define IPPROTO_IPV6_ROUTE 43
#endif
#define ROUTING_HEADER_TYPE_SR 4
/**
@brief SR header struct.
*/
typedef struct
{
/** Protocol for next header. */
u8 protocol;
/**
* Length of routing header in 8 octet units,
* not including the first 8 octets
*/
u8 length;
/** Type of routing header; type 4 = segement routing */
u8 type;
/** Next segment in the segment list */
u8 segments_left;
/**
* Policy list pointer: offset in the SRH of the policy
* list - in 16-octet units - not including the first 8 octets.
*/
u8 first_segment;
/** Flag bits */
#define IP6_SR_HEADER_FLAG_CLEANUP (0x8000)
/** Flag bits */
#define IP6_SR_HEADER_FLAG_PROTECTED (0x4000)
/** Flag bits */
#define IP6_SR_HEADER_FLAG_RESERVED (0x3000)
/** Flag bits */
#define IP6_SR_HEADER_FLAG_PL_ELT_NOT_PRESENT (0x0)
/** Flag bits */
#define IP6_SR_HEADER_FLAG_PL_ELT_INGRESS_PE (0x1)
/** Flag bits */
#define IP6_SR_HEADER_FLAG_PL_ELT_EGRESS_PE (0x2)
/** Flag bits */
#define IP6_SR_HEADER_FLAG_PL_ELT_ORIG_SRC_ADDR (0x3)
/** values 0x4 - 0x7 are reserved */
u16 flags;
u8 hmac_key;
/** The segment + policy list elts */
ip6_address_t segments[0];
} __attribute__ ((packed)) ip6_sr_header_t;
static inline int
ip6_sr_policy_list_shift_from_index (int pl_index)
{
return (-3 * pl_index) + 12;
}
/** pl_index is one-origined */
static inline int
ip6_sr_policy_list_flags (u16 flags_host_byte_order, int pl_index)
{
int shift;
if (pl_index <= 0 || pl_index > 4)
return 0;
shift = (-3 * pl_index) + 12;
flags_host_byte_order >>= shift;
return (flags_host_byte_order & 7);
}
#endif /* included_vnet_sr_packet_h */
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
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