linux/net/dsa/tag.h
Vladimir Oltean f0a9d56306 net: dsa: update TX path comments to not mention skb_mac_header()
Once commit 6d1ccff627 ("net: reset mac header in dev_start_xmit()")
will be reverted, it will no longer be true that skb->data points at
skb_mac_header(skb) - since the skb->mac_header will not be set - so
stop saying that, and just say that it points to the MAC header.

I've reviewed vlan_insert_tag() and it does not *actually* depend on
skb_mac_header(), so reword that to avoid the confusion.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-04-23 14:16:45 +01:00

311 lines
10 KiB
C

/* 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 "slave.h"
struct dsa_tag_driver {
const struct dsa_device_ops *ops;
struct list_head list;
struct module *owner;
};
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)
{
return ops->needed_headroom + ops->needed_tailroom;
}
static inline struct net_device *dsa_master_find_slave(struct net_device *dev,
int device, int port)
{
struct dsa_port *cpu_dp = dev->dsa_ptr;
struct dsa_switch_tree *dst = cpu_dp->dst;
struct dsa_port *dp;
list_for_each_entry(dp, &dst->ports, list)
if (dp->ds->index == device && dp->index == port &&
dp->type == DSA_PORT_TYPE_USER)
return dp->slave;
return NULL;
}
/* If under a bridge with vlan_filtering=0, make sure to send pvid-tagged
* frames as untagged, since the bridge will not untag them.
*/
static inline struct sk_buff *dsa_untag_bridge_pvid(struct sk_buff *skb)
{
struct dsa_port *dp = dsa_slave_to_port(skb->dev);
struct net_device *br = dsa_port_bridge_dev_get(dp);
struct net_device *dev = skb->dev;
struct net_device *upper_dev;
u16 vid, pvid, proto;
int err;
if (!br || br_vlan_enabled(br))
return skb;
err = br_vlan_get_proto(br, &proto);
if (err)
return skb;
/* Move VLAN tag from data to hwaccel */
if (!skb_vlan_tag_present(skb) && skb->protocol == htons(proto)) {
skb = skb_vlan_untag(skb);
if (!skb)
return NULL;
}
if (!skb_vlan_tag_present(skb))
return skb;
vid = skb_vlan_tag_get_id(skb);
/* We already run under an RCU read-side critical section since
* we are called from netif_receive_skb_list_internal().
*/
err = br_vlan_get_pvid_rcu(dev, &pvid);
if (err)
return skb;
if (vid != pvid)
return skb;
/* The sad part about attempting to untag from DSA is that we
* don't know, unless we check, if the skb will end up in
* the bridge's data path - br_allowed_ingress() - or not.
* For example, there might be an 8021q upper for the
* default_pvid of the bridge, which will steal VLAN-tagged traffic
* from the bridge's data path. This is a configuration that DSA
* supports because vlan_filtering is 0. In that case, we should
* definitely keep the tag, to make sure it keeps working.
*/
upper_dev = __vlan_find_dev_deep_rcu(br, htons(proto), vid);
if (upper_dev)
return skb;
__vlan_hwaccel_clear_tag(skb);
return 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 *master, u16 vid)
{
struct dsa_port *cpu_dp = master->dsa_ptr;
struct dsa_switch_tree *dst = cpu_dp->dst;
struct bridge_vlan_info vinfo;
struct net_device *slave;
struct dsa_port *dp;
int err;
list_for_each_entry(dp, &dst->ports, list) {
if (dp->type != DSA_PORT_TYPE_USER)
continue;
if (!dp->bridge)
continue;
if (dp->stp_state != BR_STATE_LEARNING &&
dp->stp_state != BR_STATE_FORWARDING)
continue;
/* Since the bridge might learn this packet, keep the CPU port
* affinity with the port that will be used for the reply on
* xmit.
*/
if (dp->cpu_dp != cpu_dp)
continue;
slave = dp->slave;
err = br_vlan_get_info_rcu(slave, vid, &vinfo);
if (err)
continue;
return slave;
}
return NULL;
}
/* 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)
{
struct dsa_port *dp = dsa_slave_to_port(skb->dev);
skb->offload_fwd_mark = !!(dp->bridge);
}
/* 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)
{
memmove(skb->data - ETH_HLEN, skb->data - ETH_HLEN - len, 2 * ETH_ALEN);
}
/* 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)
{
memmove(skb->data, skb->data + len, 2 * ETH_ALEN);
}
/* On RX, eth_type_trans() on the DSA master pulls ETH_HLEN bytes starting from
* skb_mac_header(skb), which leaves skb->data pointing at the first byte after
* what the DSA master 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)
{
return skb->data - 2;
}
/* 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)
{
return skb->data + 2 * ETH_ALEN;
}
/* 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 "dsa_tag:"
#define MODULE_ALIAS_DSA_TAG_DRIVER(__proto, __name) \
MODULE_ALIAS(DSA_TAG_DRIVER_ALIAS __name); \
MODULE_ALIAS(DSA_TAG_DRIVER_ALIAS "id-" \
__stringify(__proto##_VALUE))
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) \
static int __init dsa_tag_driver_module_init(void) \
{ \
dsa_tag_drivers_register(__dsa_tag_drivers_array, __count, \
THIS_MODULE); \
return 0; \
} \
module_init(dsa_tag_driver_module_init); \
\
static void __exit dsa_tag_driver_module_exit(void) \
{ \
dsa_tag_drivers_unregister(__dsa_tag_drivers_array, __count); \
} \
module_exit(dsa_tag_driver_module_exit)
/**
* 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) \
dsa_tag_driver_module_drivers(__ops_array, ARRAY_SIZE(__ops_array))
#define DSA_TAG_DRIVER_NAME(__ops) dsa_tag_driver ## _ ## __ops
/* Create a static structure we can build a linked list of dsa_tag
* drivers
*/
#define DSA_TAG_DRIVER(__ops) \
static struct dsa_tag_driver DSA_TAG_DRIVER_NAME(__ops) = { \
.ops = &__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) \
DSA_TAG_DRIVER(__ops); \
\
static struct dsa_tag_driver *dsa_tag_driver_array[] = { \
&DSA_TAG_DRIVER_NAME(__ops) \
}; \
module_dsa_tag_drivers(dsa_tag_driver_array)
#endif