1 #ifndef included_vnet_sr_packet_h
2 #define included_vnet_sr_packet_h
4 #include <vnet/ip/ip.h>
7 * ipv6 segment-routing header format
9 * Copyright (c) 2013 Cisco and/or its affiliates.
10 * Licensed under the Apache License, Version 2.0 (the "License");
11 * you may not use this file except in compliance with the License.
12 * You may obtain a copy of the License at:
14 * http://www.apache.org/licenses/LICENSE-2.0
16 * Unless required by applicable law or agreed to in writing, software
17 * distributed under the License is distributed on an "AS IS" BASIS,
18 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19 * See the License for the specific language governing permissions and
20 * limitations under the License.
25 * @brief The Segment Routing Header (SRH).
27 * The Segment Routing Header (SRH) is defined in the diagram below.
31 * 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
32 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
33 * | Next Header | Hdr Ext Len | Routing Type | Segments Left |
34 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
35 * | First Segment | Flags | HMAC Key ID |
36 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
38 * | Segment List[0] (128 bits ipv6 address) |
41 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
47 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
49 * | Segment List[n] (128 bits ipv6 address) |
52 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
54 * | Policy List[0] (optional) |
57 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
59 * | Policy List[1] (optional) |
62 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
64 * | Policy List[2] (optional) |
67 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
76 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
80 * o Next Header: 8-bit selector. Identifies the type of header
81 * immediately following the SRH.
83 * o Hdr Ext Len: 8-bit unsigned integer, is the length of the SRH
84 * header in 8-octet units, not including the first 8 octets.
86 * o Routing Type: TBD, to be assigned by IANA (suggested value: 4).
88 * o Segments Left. Defined in [RFC2460], it contains the index, in
89 * the Segment List, of the next segment to inspect. Segments Left
90 * is decremented at each segment and it is used as an index in the
93 * o First Segment: offset in the SRH, not including the first 8 octets
94 * and expressed in 16-octet units, pointing to the last element of
95 * the segment list, which is in fact the first segment of the
96 * segment routing path.
98 * o Flags: 16 bits of flags. Following flags are defined:
101 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
102 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
103 * |C|P|R|R| Policy Flags |
104 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
106 * C-flag: Clean-up flag. Set when the SRH has to be removed from
107 * the packet when packet reaches the last segment.
109 * P-flag: Protected flag. Set when the packet has been rerouted
110 * through FRR mechanism by a SR endpoint node. See Section 6.3
113 * R-flags. Reserved and for future use.
115 * Policy Flags. Define the type of the IPv6 addresses encoded
116 * into the Policy List (see below). The following have been
119 * Bits 4-6: determine the type of the first element after the
122 * Bits 7-9: determine the type of the second element.
124 * Bits 10-12: determine the type of the third element.
126 * Bits 13-15: determine the type of the fourth element.
128 * The following values are used for the type:
130 * 0x0: Not present. If value is set to 0x0, it means the
131 * element represented by these bits is not present.
137 * 0x3: Original Source Address.
139 * o HMAC Key ID and HMAC field, and their use are defined in
140 * [I-D.vyncke-6man-segment-routing-security].
142 * o Segment List[n]: 128 bit IPv6 addresses representing the nth
143 * segment in the Segment List. The Segment List is encoded starting
144 * from the last segment of the path. I.e., the first element of the
145 * segment list (Segment List [0]) contains the last segment of the
146 * path while the last segment of the Segment List (Segment List[n])
147 * contains the first segment of the path. The index contained in
148 * "Segments Left" identifies the current active segment.
150 * o Policy List. Optional addresses representing specific nodes in
151 * the SR path such as:
153 * SR Ingress: a 128 bit generic identifier representing the
154 * ingress in the SR domain (i.e.: it needs not to be a valid IPv6
157 * SR Egress: a 128 bit generic identifier representing the egress
158 * in the SR domain (i.e.: it needs not to be a valid IPv6
161 * Original Source Address: IPv6 address originally present in the
162 * SA field of the packet.
164 * The segments in the Policy List are encoded after the segment list
165 * and they are optional. If none are in the SRH, all bits of the
166 * Policy List Flags MUST be set to 0x0.
169 #ifndef IPPROTO_IPV6_ROUTE
170 #define IPPROTO_IPV6_ROUTE 43
173 #define ROUTING_HEADER_TYPE_SR 4
175 @brief SR header struct.
179 /** Protocol for next header. */
183 * Length of routing header in 8 octet units,
184 * not including the first 8 octets
188 /** Type of routing header; type 4 = segement routing */
191 /** Next segment in the segment list */
195 * Policy list pointer: offset in the SRH of the policy
196 * list - in 16-octet units - not including the first 8 octets.
201 #define IP6_SR_HEADER_FLAG_CLEANUP (0x8000)
203 #define IP6_SR_HEADER_FLAG_PROTECTED (0x4000)
205 #define IP6_SR_HEADER_FLAG_RESERVED (0x3000)
207 #define IP6_SR_HEADER_FLAG_PL_ELT_NOT_PRESENT (0x0)
209 #define IP6_SR_HEADER_FLAG_PL_ELT_INGRESS_PE (0x1)
211 #define IP6_SR_HEADER_FLAG_PL_ELT_EGRESS_PE (0x2)
213 #define IP6_SR_HEADER_FLAG_PL_ELT_ORIG_SRC_ADDR (0x3)
214 /** values 0x4 - 0x7 are reserved */
218 /** The segment + policy list elts */
219 ip6_address_t segments[0];
220 } __attribute__ ((packed)) ip6_sr_header_t;
223 ip6_sr_policy_list_shift_from_index (int pl_index)
225 return (-3 * pl_index) + 12;
228 /** pl_index is one-origined */
230 ip6_sr_policy_list_flags (u16 flags_host_byte_order, int pl_index)
234 if (pl_index <= 0 || pl_index > 4)
237 shift = (-3 * pl_index) + 12;
238 flags_host_byte_order >>= shift;
240 return (flags_host_byte_order & 7);
243 #endif /* included_vnet_sr_packet_h */
246 * fd.io coding-style-patch-verification: ON
249 * eval: (c-set-style "gnu")