linux/net/dsa/tag.h

/* SPDX-License-Identifier: GPL-2.0-or-later */

#ifndef __DSA_TAG_H
#define __DSA_TAG_H

#include <linux/if_vlan.h>
#include <linux/list.h>
#include <linux/types.h>
#include <net/dsa.h>

#include "port.h"
#include "user.h"

struct dsa_tag_driver {};

extern struct packet_type dsa_pack_type;

const struct dsa_device_ops *dsa_tag_driver_get_by_id(int tag_protocol);
const struct dsa_device_ops *dsa_tag_driver_get_by_name(const char *name);
void dsa_tag_driver_put(const struct dsa_device_ops *ops);
const char *dsa_tag_protocol_to_str(const struct dsa_device_ops *ops);

static inline int dsa_tag_protocol_overhead(const struct dsa_device_ops *ops)
{}

static inline struct net_device *dsa_conduit_find_user(struct net_device *dev,
						       int device, int port)
{}

/**
 * dsa_software_untag_vlan_aware_bridge: Software untagging for VLAN-aware bridge
 * @skb: Pointer to received socket buffer (packet)
 * @br: Pointer to bridge upper interface of ingress port
 * @vid: Parsed VID from packet
 *
 * The bridge can process tagged packets. Software like STP/PTP may not. The
 * bridge can also process untagged packets, to the same effect as if they were
 * tagged with the PVID of the ingress port. So packets tagged with the PVID of
 * the bridge port must be software-untagged, to support both use cases.
 */
static inline void dsa_software_untag_vlan_aware_bridge(struct sk_buff *skb,
							struct net_device *br,
							u16 vid)
{}

/**
 * dsa_software_untag_vlan_unaware_bridge: Software untagging for VLAN-unaware bridge
 * @skb: Pointer to received socket buffer (packet)
 * @br: Pointer to bridge upper interface of ingress port
 * @vid: Parsed VID from packet
 *
 * The bridge ignores all VLAN tags. Software like STP/PTP may not (it may run
 * on the plain port, or on a VLAN upper interface). Maybe packets are coming
 * to software as tagged with a driver-defined VID which is NOT equal to the
 * PVID of the bridge port (since the bridge is VLAN-unaware, its configuration
 * should NOT be committed to hardware). DSA needs a method for this private
 * VID to be communicated by software to it, and if packets are tagged with it,
 * software-untag them. Note: the private VID may be different per bridge, to
 * support the FDB isolation use case.
 *
 * FIXME: this is currently implemented based on the broken assumption that
 * the "private VID" used by the driver in VLAN-unaware mode is equal to the
 * bridge PVID. It should not be, except for a coincidence; the bridge PVID is
 * irrelevant to the data path in the VLAN-unaware mode. Thus, the VID that
 * this function removes is wrong.
 *
 * All users of ds->untag_bridge_pvid should fix their drivers, if necessary,
 * to make the two independent. Only then, if there still remains a need to
 * strip the private VID from packets, then a new ds->ops->get_private_vid()
 * API shall be introduced to communicate to DSA what this VID is, which needs
 * to be stripped here.
 */
static inline void dsa_software_untag_vlan_unaware_bridge(struct sk_buff *skb,
							  struct net_device *br,
							  u16 vid)
{}

/**
 * dsa_software_vlan_untag: Software VLAN untagging in DSA receive path
 * @skb: Pointer to socket buffer (packet)
 *
 * Receive path method for switches which cannot avoid tagging all packets
 * towards the CPU port. Called when ds->untag_bridge_pvid (legacy) or
 * ds->untag_vlan_aware_bridge_pvid is set to true.
 *
 * As a side effect of this method, any VLAN tag from the skb head is moved
 * to hwaccel.
 */
static inline struct sk_buff *dsa_software_vlan_untag(struct sk_buff *skb)
{}

/* For switches without hardware support for DSA tagging to be able
 * to support termination through the bridge.
 */
static inline struct net_device *
dsa_find_designated_bridge_port_by_vid(struct net_device *conduit, u16 vid)
{}

/* If the ingress port offloads the bridge, we mark the frame as autonomously
 * forwarded by hardware, so the software bridge doesn't forward in twice, back
 * to us, because we already did. However, if we're in fallback mode and we do
 * software bridging, we are not offloading it, therefore the dp->bridge
 * pointer is not populated, and flooding needs to be done by software (we are
 * effectively operating in standalone ports mode).
 */
static inline void dsa_default_offload_fwd_mark(struct sk_buff *skb)
{}

/* Helper for removing DSA header tags from packets in the RX path.
 * Must not be called before skb_pull(len).
 *                                                                 skb->data
 *                                                                         |
 *                                                                         v
 * |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
 * +-----------------------+-----------------------+---------------+-------+
 * |    Destination MAC    |      Source MAC       |  DSA header   | EType |
 * +-----------------------+-----------------------+---------------+-------+
 *                                                 |               |
 * <----- len ----->                               <----- len ----->
 *                 |
 *       >>>>>>>   v
 *       >>>>>>>   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
 *       >>>>>>>   +-----------------------+-----------------------+-------+
 *       >>>>>>>   |    Destination MAC    |      Source MAC       | EType |
 *                 +-----------------------+-----------------------+-------+
 *                                                                         ^
 *                                                                         |
 *                                                                 skb->data
 */
static inline void dsa_strip_etype_header(struct sk_buff *skb, int len)
{}

/* Helper for creating space for DSA header tags in TX path packets.
 * Must not be called before skb_push(len).
 *
 * Before:
 *
 *       <<<<<<<   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
 * ^     <<<<<<<   +-----------------------+-----------------------+-------+
 * |     <<<<<<<   |    Destination MAC    |      Source MAC       | EType |
 * |               +-----------------------+-----------------------+-------+
 * <----- len ----->
 * |
 * |
 * skb->data
 *
 * After:
 *
 * |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
 * +-----------------------+-----------------------+---------------+-------+
 * |    Destination MAC    |      Source MAC       |  DSA header   | EType |
 * +-----------------------+-----------------------+---------------+-------+
 * ^                                               |               |
 * |                                               <----- len ----->
 * skb->data
 */
static inline void dsa_alloc_etype_header(struct sk_buff *skb, int len)
{}

/* On RX, eth_type_trans() on the DSA conduit pulls ETH_HLEN bytes starting from
 * skb_mac_header(skb), which leaves skb->data pointing at the first byte after
 * what the DSA conduit perceives as the EtherType (the beginning of the L3
 * protocol). Since DSA EtherType header taggers treat the EtherType as part of
 * the DSA tag itself, and the EtherType is 2 bytes in length, the DSA header
 * is located 2 bytes behind skb->data. Note that EtherType in this context
 * means the first 2 bytes of the DSA header, not the encapsulated EtherType
 * that will become visible after the DSA header is stripped.
 */
static inline void *dsa_etype_header_pos_rx(struct sk_buff *skb)
{}

/* On TX, skb->data points to the MAC header, which means that EtherType
 * header taggers start exactly where the EtherType is (the EtherType is
 * treated as part of the DSA header).
 */
static inline void *dsa_etype_header_pos_tx(struct sk_buff *skb)
{}

/* Create 2 modaliases per tagging protocol, one to auto-load the module
 * given the ID reported by get_tag_protocol(), and the other by name.
 */
#define DSA_TAG_DRIVER_ALIAS
#define MODULE_ALIAS_DSA_TAG_DRIVER(__proto, __name)

void dsa_tag_drivers_register(struct dsa_tag_driver *dsa_tag_driver_array[],
			      unsigned int count,
			      struct module *owner);
void dsa_tag_drivers_unregister(struct dsa_tag_driver *dsa_tag_driver_array[],
				unsigned int count);

#define dsa_tag_driver_module_drivers(__dsa_tag_drivers_array, __count)

/**
 * module_dsa_tag_drivers() - Helper macro for registering DSA tag
 * drivers
 * @__ops_array: Array of tag driver structures
 *
 * Helper macro for DSA tag drivers which do not do anything special
 * in module init/exit. Each module may only use this macro once, and
 * calling it replaces module_init() and module_exit().
 */
#define module_dsa_tag_drivers(__ops_array)

#define DSA_TAG_DRIVER_NAME(__ops)

/* Create a static structure we can build a linked list of dsa_tag
 * drivers
 */
#define DSA_TAG_DRIVER(__ops)

/**
 * module_dsa_tag_driver() - Helper macro for registering a single DSA tag
 * driver
 * @__ops: Single tag driver structures
 *
 * Helper macro for DSA tag drivers which do not do anything special
 * in module init/exit. Each module may only use this macro once, and
 * calling it replaces module_init() and module_exit().
 */
#define module_dsa_tag_driver(__ops)

#endif