Function vxlan_rcv_udp_packet

freebsd/net/if_vxlan.c:2749–2792

}

static void
vxlan_rcv_udp_packet(struct mbuf *m, int offset, struct inpcb *inpcb,
    const struct sockaddr *srcsa, void *xvso)
{
	struct vxlan_socket *vso;
	struct vxlan_header *vxh, vxlanhdr;
	uint32_t vni;
	int error __unused;

	M_ASSERTPKTHDR(m);
	vso = xvso;
	offset += sizeof(struct udphdr);

	if (m->m_pkthdr.len < offset + sizeof(struct vxlan_header))
		goto out;

	if (__predict_false(m->m_len < offset + sizeof(struct vxlan_header))) {
		m_copydata(m, offset, sizeof(struct vxlan_header),
		    (caddr_t) &vxlanhdr);
		vxh = &vxlanhdr;
	} else
		vxh = mtodo(m, offset);

	/*
	 * Drop if there is a reserved bit set in either the flags or VNI
	 * fields of the header. This goes against the specification, but
	 * a bit set may indicate an unsupported new feature. This matches
	 * the behavior of the Linux implementation.
	 */
	if (vxh->vxlh_flags != htonl(VXLAN_HDR_FLAGS_VALID_VNI) ||
	    vxh->vxlh_vni & ~VXLAN_VNI_MASK)
		goto out;

	vni = ntohl(vxh->vxlh_vni) >> VXLAN_HDR_VNI_SHIFT;
	/* Adjust to the start of the inner Ethernet frame. */
	m_adj(m, offset + sizeof(struct vxlan_header));

	error = vxlan_input(vso, vni, &m, srcsa);
	MPASS(error != 0 || m == NULL);

out:
	if (m != NULL)
		m_freem(m);
}

static int
vxlan_input(struct vxlan_socket *vso, uint32_t vni, struct mbuf **m0,