NAME

SYNOPSIS

DESCRIPTION

The VXLAN header contains two 32-bit words. The first word is an 8-bit flags field followed by 24 reserved bits. The second word is a 24-bit virtual network identifier followed by 8 reserved bits. The virtual network identifier identifies a unique VXLAN and is similar in concept to an IEEE 802.1Q VLAN identifier.

The system provides access to VXLAN through dladm overlays. See dladm(8) and overlay(7) for more information.

The <sys/vxlan.h> header provides information for working with the VXLAN protocol. The contents of this header are uncommitted. The header defines a structure that may be used to encode and decode a VXLAN header. It defines a packed structure type vxlan_hdr_t which represents the VXLAN frame header and has the following members:

	uint32_t	vxlan_flags;	/* flags in upper 8 bits */
	uint32_t	vxlan_id;	/* VXLAN ID in upper 24 bits */

EXAMPLES

The following example shows how to validate a header. For more information on this process, see RFC 7348.

#include <sys/types.h>
#include <netinet/in.h>
#include <inttypes.h>
#include <sys/vxlan.h>

...

/*
 * Validate the following bytes as a VXLAN header. If valid, return
 * 0 and store the VXLAN identifier in *vidp. Otherwise, return an
 * error.
 */
int
validate_vxlan(void *buf, int len, uint32_t *vidp)
{
	vxlan_hdr_t *hdr;

	if (len < sizeof (vxlan_hdr_t))
		return (EINAVL);

	hdr = buf;
	if ((ntohl(hdr->vxlan_flags) & VXLAN_MAGIC) == 0)
		return (EINAVL);

	*vidp = ntohl(vxlan->vxlan_id) >> VXLAN_ID_SHIFT;

	return (0);
}

STABILITY

SEE ALSO

Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger L., Sridhar, T., Bursell, M., and C. Wright, RFC 7348, Virtual eXtensible Local Area Network (VXLAN): A Framework, for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks, August 2014.