sr_packet.h revision 8bf80a3d
1#ifndef included_vnet_sr_packet_h
2#define included_vnet_sr_packet_h
3
4#include <vnet/ip/ip.h>
5
6/*
7 * ipv6 segment-routing header format
8 *
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:
13 *
14 *     http://www.apache.org/licenses/LICENSE-2.0
15 *
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.
21 */
22
23/*
24 *   The Segment Routing Header (SRH) is defined as follows:
25 *
26 *    0                   1                   2                   3
27 *    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
28 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
29 *   | Next Header   |  Hdr Ext Len  | Routing Type  | Segments Left |
30 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
31 *   |  Last Entry   |     Flags     |              Tag              |
32 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
33 *   |                                                               |
34 *   |            Segment List[0] (128 bits IPv6 address)            |
35 *   |                                                               |
36 *   |                                                               |
37 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
38 *   |                                                               |
39 *   |                                                               |
40 *                                 ...
41 *   |                                                               |
42 *   |                                                               |
43 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
44 *   |                                                               |
45 *   |            Segment List[n] (128 bits IPv6 address)            |
46 *   |                                                               |
47 *   |                                                               |
48 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
49 *   //                                                             //
50 *   //         Optional Type Length Value objects (variable)       //
51 *   //                                                             //
52 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
53 *
54 *   where:
55 *
56 *   o  Next Header: 8-bit selector.  Identifies the type of header
57 *      immediately following the SRH.
58 *
59 *   o  Hdr Ext Len: 8-bit unsigned integer, is the length of the SRH
60 *      header in 8-octet units, not including the first 8 octets.
61 *
62 *   o  Routing Type: TBD, to be assigned by IANA (suggested value: 4).
63 *
64 *   o  Segments Left.  Defined in [RFC8200], it contains the index, in
65 *      the Segment List, of the next segment to inspect.  Segments Left
66 *      is decremented at each segment.
67 *
68 *   o  Last Entry: contains the index (zero based), in the Segment List,
69 *      of the the last element of the Segment List
70 *
71 *   o  Flags: 8 bits of flags.  Following flags are defined:
72 *
73 *         0 1 2 3 4 5 6 7
74 *        +-+-+-+-+-+-+-+-+
75 *        |U|P|O|A|H|  U  |
76 *        +-+-+-+-+-+-+-+-+
77 *
78 *        U: Unused and for future use.  SHOULD be unset on transmission
79 *        and MUST be ignored on receipt.
80 *
81 *        P-flag: Protected flag.  Set when the packet has been rerouted
82 *        through FRR mechanism by an SR endpoint node.
83 *
84 *        O-flag: OAM flag.  When set, it indicates that this packet is
85 *        an operations and management (OAM) packet.
86 *
87 *        A-flag: Alert flag.  If present, it means important Type Length
88 *        Value (TLV) objects are present.  See Section 3.1 for details
89 *        on TLVs objects.
90 *
91 *        H-flag: HMAC flag.  If set, the HMAC TLV is present and is
92 *        encoded as the last TLV of the SRH.  In other words, the last
93 *        36 octets of the SRH represent the HMAC information.  See
94 *        Section 3.1.5 for details on the HMAC TLV.
95 *
96 *   o  Tag: tag a packet as part of a class or group of packets, e.g.,
97 *      packets sharing the same set of properties. When tag is not used
98 *      at source it MUST be set to zero on transmission. When tag is not
99 *      used during SRH Processing it SHOULD be ignored.
100 *
101 *   o  Segment List[n]: 128 bit IPv6 addresses representing the nth
102 *      segment in the Segment List.  The Segment List is encoded starting
103 *      from the last segment of the path.  I.e., the first element of the
104 *      segment list (Segment List [0]) contains the last segment of the
105 *      path while the last segment of the Segment List (Segment List[n])
106 *      contains the first segment of the path.  The index contained in
107 *      "Segments Left" identifies the current active segment.
108 *
109 *   o  Type Length Value (TLV) are described in Section 3.1.
110 *
111 */
112
113#ifndef IPPROTO_IPV6_ROUTE
114#define IPPROTO_IPV6_ROUTE        43
115#endif
116
117#define ROUTING_HEADER_TYPE_SR    4
118
119typedef struct
120{
121  /* Protocol for next header. */
122  u8 protocol;
123  /*
124   * Length of routing header in 8 octet units,
125   * not including the first 8 octets
126   */
127  u8 length;
128
129  /* Type of routing header; type 4 = segement routing */
130  u8 type;
131
132  /* Next segment in the segment list */
133  u8 segments_left;
134
135  /* Pointer to the first segment in the header */
136  u8 last_entry;
137
138  /* Flag bits */
139#define IP6_SR_HEADER_FLAG_PROTECTED  (0x40)
140#define IP6_SR_HEADER_FLAG_OAM        (0x20)
141#define IP6_SR_HEADER_FLAG_ALERT      (0x10)
142#define IP6_SR_HEADER_FLAG_HMAC       (0x80)
143
144  /* values 0x0, 0x4 - 0x7 are reserved */
145  u8 flags;
146  u16 tag;
147
148  /* The segment elts */
149  ip6_address_t segments[0];
150} __attribute__ ((packed)) ip6_sr_header_t;
151
152typedef struct
153{
154  u8 type;
155  u8 length;
156  u8 value[0];
157} __attribute__ ((packed)) ip6_sr_tlv_t;
158
159/*
160* fd.io coding-style-patch-verification: ON
161*
162* Local Variables:
163* eval: (c-set-style "gnu")
164* End:
165*/
166
167#endif /* included_vnet_sr_packet_h */
168