vxlan_packet.h

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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_vxlan_packet_h__
#define __included_vxlan_packet_h__ 1

/* 
 * From RFC-7384
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |R|R|R|R|I|R|R|R|            Reserved                           |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                VXLAN Network Identifier (VNI) |   Reserved    |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * 
 * VXLAN Header:  This is an 8-byte field that has:
 * 
 * - Flags (8 bits): where the I flag MUST be set to 1 for a valid
 * VXLAN Network ID (VNI).  The other 7 bits (designated "R") are
 * reserved fields and MUST be set to zero on transmission and
 * ignored on receipt.
 * 
 * - VXLAN Segment ID/VXLAN Network Identifier (VNI): this is a
 * 24-bit value used to designate the individual VXLAN overlay
 * network on which the communicating VMs are situated.  VMs in
 * different VXLAN overlay networks cannot communicate with each
 * other.
 * 
 * - Reserved fields (24 bits and 8 bits): MUST be set to zero on
 * transmission and ignored on receipt.
 * 
 */

typedef struct {
  u32 flags;
  u32 vni_reserved;
} vxlan_header_t;

#define VXLAN_FLAGS_VALID_HOST_BYTE_ORDER (1<<27)
#define VXLAN_FLAGS_VALID_NET_BYTE_ORDER (clib_host_to_net_u32(1<<27))

static inline u32 vnet_get_vni (vxlan_header_t * h)
{
  u32 vni_reserved_host_byte_order;

  vni_reserved_host_byte_order = clib_net_to_host_u32 (h->vni_reserved);
  return vni_reserved_host_byte_order >> 8;
}

static inline void vnet_set_vni_and_flags (vxlan_header_t * h, u32 vni)
{
  h->vni_reserved = clib_host_to_net_u32 (vni<<8);
  h->flags = VXLAN_FLAGS_VALID_NET_BYTE_ORDER;
}

#endif /* __included_vxlan_packet_h__ */