freebsd-skq/sys/net/if_vlan_var.h
yar a8babb6361 Use VLAN_TAG_VALUE() not only to read a dot1q tag
value from an m_tag, but also to set it.  This reduces
complex code duplication and improves its readability.

Alas, we shouldn't rename the macro to VLAN_TAG_LVALUE()
globally because that would cause pain for kernel module
port maintainers and vendors using FreeBSD as their codebase.
Added a clarifying comment instead.

Discussed with:	ru, glebius
X-MFC-After:	6.0-RELEASE (MFC is good just to reduce the diff)
2005-08-31 11:36:50 +00:00

125 lines
4.3 KiB
C

/*-
* Copyright 1998 Massachusetts Institute of Technology
*
* Permission to use, copy, modify, and distribute this software and
* its documentation for any purpose and without fee is hereby
* granted, provided that both the above copyright notice and this
* permission notice appear in all copies, that both the above
* copyright notice and this permission notice appear in all
* supporting documentation, and that the name of M.I.T. not be used
* in advertising or publicity pertaining to distribution of the
* software without specific, written prior permission. M.I.T. makes
* no representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied
* warranty.
*
* THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''. M.I.T. DISCLAIMS
* ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
* SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _NET_IF_VLAN_VAR_H_
#define _NET_IF_VLAN_VAR_H_ 1
struct ether_vlan_header {
u_char evl_dhost[ETHER_ADDR_LEN];
u_char evl_shost[ETHER_ADDR_LEN];
u_int16_t evl_encap_proto;
u_int16_t evl_tag;
u_int16_t evl_proto;
};
#define EVL_VLID_MASK 0x0FFF
#define EVL_VLANOFTAG(tag) ((tag) & EVL_VLID_MASK)
#define EVL_PRIOFTAG(tag) (((tag) >> 13) & 7)
/* sysctl(3) tags, for compatibility purposes */
#define VLANCTL_PROTO 1
#define VLANCTL_MAX 2
/*
* Configuration structure for SIOCSETVLAN and SIOCGETVLAN ioctls.
*/
struct vlanreq {
char vlr_parent[IFNAMSIZ];
u_short vlr_tag;
};
#define SIOCSETVLAN SIOCSIFGENERIC
#define SIOCGETVLAN SIOCGIFGENERIC
#ifdef _KERNEL
/*
* Drivers that are capable of adding and removing the VLAN header
* in hardware indicate they support this by marking IFCAP_VLAN_HWTAGGING
* in if_capabilities. Drivers for hardware that is capable
* of handling larger MTU's that may include a software-appended
* VLAN header w/o lowering the normal MTU should mark IFCAP_VLAN_MTU
* in if_capabilities; this notifies the VLAN code it can leave the
* MTU on the vlan interface at the normal setting.
*/
/*
* Drivers that support hardware VLAN tagging pass a packet's tag
* up through the stack by appending a packet tag with this value.
* Output is handled likewise, the driver must locate the packet
* tag to extract the VLAN tag. The following macros are used to
* do this work. On input, do:
*
* VLAN_INPUT_TAG(ifp, m, tag,);
*
* to mark the packet m with the specified VLAN tag. The last
* parameter provides code to execute in case of an error. On
* output the driver should check mbuf to see if a VLAN tag is
* present and only then check for a tag; this is done with:
*
* struct m_tag *mtag;
* mtag = VLAN_OUTPUT_TAG(ifp, m);
* if (mtag != NULL) {
* ... = VLAN_TAG_VALUE(mtag);
* ... pass tag to hardware ...
* }
*
* Note that a driver must indicate it supports hardware VLAN
* tagging by marking IFCAP_VLAN_HWTAGGING in if_capabilities.
*/
#define MTAG_VLAN 1035328035
#define MTAG_VLAN_TAG 0 /* tag of VLAN interface */
/*
* This macro must expand to a lvalue so that it can be used
* to set a tag with a simple assignment.
*/
#define VLAN_TAG_VALUE(_mt) (*(u_int *)((_mt) + 1))
#define VLAN_INPUT_TAG(_ifp, _m, _t, _errcase) do { \
struct m_tag *mtag; \
mtag = m_tag_alloc(MTAG_VLAN, MTAG_VLAN_TAG, \
sizeof (u_int), M_NOWAIT); \
if (mtag == NULL) { \
(_ifp)->if_ierrors++; \
m_freem(_m); \
_errcase; \
} \
VLAN_TAG_VALUE(mtag) = (_t); \
m_tag_prepend((_m), mtag); \
(_m)->m_flags |= M_VLANTAG; \
} while (0)
#define VLAN_OUTPUT_TAG(_ifp, _m) \
((_m)->m_flags & M_VLANTAG ? \
m_tag_locate((_m), MTAG_VLAN, MTAG_VLAN_TAG, NULL) : NULL)
#endif /* _KERNEL */
#endif /* _NET_IF_VLAN_VAR_H_ */