#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: */