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linux-next/net/dsa/dsa_priv.h
Vladimir Oltean dc452a471d net: dsa: introduce tagger-owned storage for private and shared data 
Ansuel is working on register access over Ethernet for the qca8k switch
family. This requires the qca8k tagging protocol driver to receive
frames which aren't intended for the network stack, but instead for the
qca8k switch driver itself.

The dp->priv is currently the prevailing method for passing data back
and forth between the tagging protocol driver and the switch driver.
However, this method is riddled with caveats.

The DSA design allows in principle for any switch driver to return any
protocol it desires in ->get_tag_protocol(). The dsa_loop driver can be
modified to do just that. But in the current design, the memory behind
dp->priv has to be allocated by the switch driver, so if the tagging
protocol is paired to an unexpected switch driver, we may end up in NULL
pointer dereferences inside the kernel, or worse (a switch driver may
allocate dp->priv according to the expectations of a different tagger).

The latter possibility is even more plausible considering that DSA
switches can dynamically change tagging protocols in certain cases
(dsa <-> edsa, ocelot <-> ocelot-8021q), and the current design lends
itself to mistakes that are all too easy to make.

This patch proposes that the tagging protocol driver should manage its
own memory, instead of relying on the switch driver to do so.
After analyzing the different in-tree needs, it can be observed that the
required tagger storage is per switch, therefore a ds->tagger_data
pointer is introduced. In principle, per-port storage could also be
introduced, although there is no need for it at the moment. Future
changes will replace the current usage of dp->priv with ds->tagger_data.

We define a "binding" event between the DSA switch tree and the tagging
protocol. During this binding event, the tagging protocol's ->connect()
method is called first, and this may allocate some memory for each
switch of the tree. Then a cross-chip notifier is emitted for the
switches within that tree, and they are given the opportunity to fix up
the tagger's memory (for example, they might set up some function
pointers that represent virtual methods for consuming packets).
Because the memory is owned by the tagger, there exists a ->disconnect()
method for the tagger (which is the place to free the resources), but
there doesn't exist a ->disconnect() method for the switch driver.
This is part of the design. The switch driver should make minimal use of
the public part of the tagger data, and only after type-checking it
using the supplied "proto" argument.

In the code there are in fact two binding events, one is the initial
event in dsa_switch_setup_tag_protocol(). At this stage, the cross chip
notifier chains aren't initialized, so we call each switch's connect()
method by hand. Then there is dsa_tree_bind_tag_proto() during
dsa_tree_change_tag_proto(), and here we have an old protocol and a new
one. We first connect to the new one before disconnecting from the old
one, to simplify error handling a bit and to ensure we remain in a valid
state at all times.

Co-developed-by: Ansuel Smith <ansuelsmth@gmail.com>
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2021-12-12 12:51:33 +00:00

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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* net/dsa/dsa_priv.h - Hardware switch handling
* Copyright (c) 2008-2009 Marvell Semiconductor
*/
#ifndef __DSA_PRIV_H
#define __DSA_PRIV_H
#include <linux/if_bridge.h>
#include <linux/phy.h>
#include <linux/netdevice.h>
#include <linux/netpoll.h>
#include <net/dsa.h>
#include <net/gro_cells.h>
#define DSA_MAX_NUM_OFFLOADING_BRIDGES BITS_PER_LONG
enum {
DSA_NOTIFIER_AGEING_TIME,
DSA_NOTIFIER_BRIDGE_JOIN,
DSA_NOTIFIER_BRIDGE_LEAVE,
DSA_NOTIFIER_FDB_ADD,
DSA_NOTIFIER_FDB_DEL,
DSA_NOTIFIER_HOST_FDB_ADD,
DSA_NOTIFIER_HOST_FDB_DEL,
DSA_NOTIFIER_HSR_JOIN,
DSA_NOTIFIER_HSR_LEAVE,
DSA_NOTIFIER_LAG_CHANGE,
DSA_NOTIFIER_LAG_JOIN,
DSA_NOTIFIER_LAG_LEAVE,
DSA_NOTIFIER_MDB_ADD,
DSA_NOTIFIER_MDB_DEL,
DSA_NOTIFIER_HOST_MDB_ADD,
DSA_NOTIFIER_HOST_MDB_DEL,
DSA_NOTIFIER_VLAN_ADD,
DSA_NOTIFIER_VLAN_DEL,
DSA_NOTIFIER_MTU,
DSA_NOTIFIER_TAG_PROTO,
DSA_NOTIFIER_TAG_PROTO_CONNECT,
DSA_NOTIFIER_MRP_ADD,
DSA_NOTIFIER_MRP_DEL,
DSA_NOTIFIER_MRP_ADD_RING_ROLE,
DSA_NOTIFIER_MRP_DEL_RING_ROLE,
DSA_NOTIFIER_TAG_8021Q_VLAN_ADD,
DSA_NOTIFIER_TAG_8021Q_VLAN_DEL,
};
/* DSA_NOTIFIER_AGEING_TIME */
struct dsa_notifier_ageing_time_info {
unsigned int ageing_time;
};
/* DSA_NOTIFIER_BRIDGE_* */
struct dsa_notifier_bridge_info {
struct dsa_bridge bridge;
int tree_index;
int sw_index;
int port;
bool tx_fwd_offload;
};
/* DSA_NOTIFIER_FDB_* */
struct dsa_notifier_fdb_info {
int sw_index;
int port;
const unsigned char *addr;
u16 vid;
};
/* DSA_NOTIFIER_MDB_* */
struct dsa_notifier_mdb_info {
const struct switchdev_obj_port_mdb *mdb;
int sw_index;
int port;
};
/* DSA_NOTIFIER_LAG_* */
struct dsa_notifier_lag_info {
struct net_device *lag;
int sw_index;
int port;
struct netdev_lag_upper_info *info;
};
/* DSA_NOTIFIER_VLAN_* */
struct dsa_notifier_vlan_info {
const struct switchdev_obj_port_vlan *vlan;
int sw_index;
int port;
struct netlink_ext_ack *extack;
};
/* DSA_NOTIFIER_MTU */
struct dsa_notifier_mtu_info {
bool targeted_match;
int sw_index;
int port;
int mtu;
};
/* DSA_NOTIFIER_TAG_PROTO_* */
struct dsa_notifier_tag_proto_info {
const struct dsa_device_ops *tag_ops;
};
/* DSA_NOTIFIER_MRP_* */
struct dsa_notifier_mrp_info {
const struct switchdev_obj_mrp *mrp;
int sw_index;
int port;
};
/* DSA_NOTIFIER_MRP_* */
struct dsa_notifier_mrp_ring_role_info {
const struct switchdev_obj_ring_role_mrp *mrp;
int sw_index;
int port;
};
/* DSA_NOTIFIER_TAG_8021Q_VLAN_* */
struct dsa_notifier_tag_8021q_vlan_info {
int tree_index;
int sw_index;
int port;
u16 vid;
};
struct dsa_switchdev_event_work {
struct dsa_switch *ds;
int port;
struct net_device *dev;
struct work_struct work;
unsigned long event;
/* Specific for SWITCHDEV_FDB_ADD_TO_DEVICE and
* SWITCHDEV_FDB_DEL_TO_DEVICE
*/
unsigned char addr[ETH_ALEN];
u16 vid;
bool host_addr;
};
/* DSA_NOTIFIER_HSR_* */
struct dsa_notifier_hsr_info {
struct net_device *hsr;
int sw_index;
int port;
};
struct dsa_slave_priv {
/* Copy of CPU port xmit for faster access in slave transmit hot path */
struct sk_buff * (*xmit)(struct sk_buff *skb,
struct net_device *dev);
struct gro_cells gcells;
/* DSA port data, such as switch, port index, etc. */
struct dsa_port *dp;
#ifdef CONFIG_NET_POLL_CONTROLLER
struct netpoll *netpoll;
#endif
/* TC context */
struct list_head mall_tc_list;
};
/* dsa.c */
const struct dsa_device_ops *dsa_tag_driver_get(int tag_protocol);
void dsa_tag_driver_put(const struct dsa_device_ops *ops);
const struct dsa_device_ops *dsa_find_tagger_by_name(const char *buf);
bool dsa_schedule_work(struct work_struct *work);
void dsa_flush_workqueue(void);
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;
}
/* master.c */
int dsa_master_setup(struct net_device *dev, struct dsa_port *cpu_dp);
void dsa_master_teardown(struct net_device *dev);
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;
}
/* port.c */
void dsa_port_set_tag_protocol(struct dsa_port *cpu_dp,
const struct dsa_device_ops *tag_ops);
int dsa_port_set_state(struct dsa_port *dp, u8 state, bool do_fast_age);
int dsa_port_enable_rt(struct dsa_port *dp, struct phy_device *phy);
int dsa_port_enable(struct dsa_port *dp, struct phy_device *phy);
void dsa_port_disable_rt(struct dsa_port *dp);
void dsa_port_disable(struct dsa_port *dp);
int dsa_port_bridge_join(struct dsa_port *dp, struct net_device *br,
struct netlink_ext_ack *extack);
void dsa_port_pre_bridge_leave(struct dsa_port *dp, struct net_device *br);
void dsa_port_bridge_leave(struct dsa_port *dp, struct net_device *br);
int dsa_port_lag_change(struct dsa_port *dp,
struct netdev_lag_lower_state_info *linfo);
int dsa_port_lag_join(struct dsa_port *dp, struct net_device *lag_dev,
struct netdev_lag_upper_info *uinfo,
struct netlink_ext_ack *extack);
void dsa_port_pre_lag_leave(struct dsa_port *dp, struct net_device *lag_dev);
void dsa_port_lag_leave(struct dsa_port *dp, struct net_device *lag_dev);
int dsa_port_vlan_filtering(struct dsa_port *dp, bool vlan_filtering,
struct netlink_ext_ack *extack);
bool dsa_port_skip_vlan_configuration(struct dsa_port *dp);
int dsa_port_ageing_time(struct dsa_port *dp, clock_t ageing_clock);
int dsa_port_mtu_change(struct dsa_port *dp, int new_mtu,
bool targeted_match);
int dsa_port_fdb_add(struct dsa_port *dp, const unsigned char *addr,
u16 vid);
int dsa_port_fdb_del(struct dsa_port *dp, const unsigned char *addr,
u16 vid);
int dsa_port_host_fdb_add(struct dsa_port *dp, const unsigned char *addr,
u16 vid);
int dsa_port_host_fdb_del(struct dsa_port *dp, const unsigned char *addr,
u16 vid);
int dsa_port_fdb_dump(struct dsa_port *dp, dsa_fdb_dump_cb_t *cb, void *data);
int dsa_port_mdb_add(const struct dsa_port *dp,
const struct switchdev_obj_port_mdb *mdb);
int dsa_port_mdb_del(const struct dsa_port *dp,
const struct switchdev_obj_port_mdb *mdb);
int dsa_port_host_mdb_add(const struct dsa_port *dp,
const struct switchdev_obj_port_mdb *mdb);
int dsa_port_host_mdb_del(const struct dsa_port *dp,
const struct switchdev_obj_port_mdb *mdb);
int dsa_port_pre_bridge_flags(const struct dsa_port *dp,
struct switchdev_brport_flags flags,
struct netlink_ext_ack *extack);
int dsa_port_bridge_flags(struct dsa_port *dp,
struct switchdev_brport_flags flags,
struct netlink_ext_ack *extack);
int dsa_port_vlan_add(struct dsa_port *dp,
const struct switchdev_obj_port_vlan *vlan,
struct netlink_ext_ack *extack);
int dsa_port_vlan_del(struct dsa_port *dp,
const struct switchdev_obj_port_vlan *vlan);
int dsa_port_mrp_add(const struct dsa_port *dp,
const struct switchdev_obj_mrp *mrp);
int dsa_port_mrp_del(const struct dsa_port *dp,
const struct switchdev_obj_mrp *mrp);
int dsa_port_mrp_add_ring_role(const struct dsa_port *dp,
const struct switchdev_obj_ring_role_mrp *mrp);
int dsa_port_mrp_del_ring_role(const struct dsa_port *dp,
const struct switchdev_obj_ring_role_mrp *mrp);
int dsa_port_phylink_create(struct dsa_port *dp);
int dsa_port_link_register_of(struct dsa_port *dp);
void dsa_port_link_unregister_of(struct dsa_port *dp);
int dsa_port_hsr_join(struct dsa_port *dp, struct net_device *hsr);
void dsa_port_hsr_leave(struct dsa_port *dp, struct net_device *hsr);
int dsa_port_tag_8021q_vlan_add(struct dsa_port *dp, u16 vid, bool broadcast);
void dsa_port_tag_8021q_vlan_del(struct dsa_port *dp, u16 vid, bool broadcast);
/* slave.c */
extern const struct dsa_device_ops notag_netdev_ops;
extern struct notifier_block dsa_slave_switchdev_notifier;
extern struct notifier_block dsa_slave_switchdev_blocking_notifier;
void dsa_slave_mii_bus_init(struct dsa_switch *ds);
int dsa_slave_create(struct dsa_port *dp);
void dsa_slave_destroy(struct net_device *slave_dev);
int dsa_slave_suspend(struct net_device *slave_dev);
int dsa_slave_resume(struct net_device *slave_dev);
int dsa_slave_register_notifier(void);
void dsa_slave_unregister_notifier(void);
void dsa_slave_setup_tagger(struct net_device *slave);
int dsa_slave_change_mtu(struct net_device *dev, int new_mtu);
int dsa_slave_manage_vlan_filtering(struct net_device *dev,
bool vlan_filtering);
static inline struct dsa_port *dsa_slave_to_port(const struct net_device *dev)
{
struct dsa_slave_priv *p = netdev_priv(dev);
return p->dp;
}
static inline struct net_device *
dsa_slave_to_master(const struct net_device *dev)
{
struct dsa_port *dp = dsa_slave_to_port(dev);
return dp->cpu_dp->master;
}
/* 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 skb_mac_header(skb), 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;
}
/* switch.c */
int dsa_switch_register_notifier(struct dsa_switch *ds);
void dsa_switch_unregister_notifier(struct dsa_switch *ds);
/* dsa2.c */
void dsa_lag_map(struct dsa_switch_tree *dst, struct net_device *lag);
void dsa_lag_unmap(struct dsa_switch_tree *dst, struct net_device *lag);
int dsa_tree_notify(struct dsa_switch_tree *dst, unsigned long e, void *v);
int dsa_broadcast(unsigned long e, void *v);
int dsa_tree_change_tag_proto(struct dsa_switch_tree *dst,
struct net_device *master,
const struct dsa_device_ops *tag_ops,
const struct dsa_device_ops *old_tag_ops);
unsigned int dsa_bridge_num_get(const struct net_device *bridge_dev, int max);
void dsa_bridge_num_put(const struct net_device *bridge_dev,
unsigned int bridge_num);
struct dsa_bridge *dsa_tree_bridge_find(struct dsa_switch_tree *dst,
const struct net_device *br);
/* tag_8021q.c */
int dsa_tag_8021q_bridge_join(struct dsa_switch *ds,
struct dsa_notifier_bridge_info *info);
int dsa_tag_8021q_bridge_leave(struct dsa_switch *ds,
struct dsa_notifier_bridge_info *info);
int dsa_switch_tag_8021q_vlan_add(struct dsa_switch *ds,
struct dsa_notifier_tag_8021q_vlan_info *info);
int dsa_switch_tag_8021q_vlan_del(struct dsa_switch *ds,
struct dsa_notifier_tag_8021q_vlan_info *info);
extern struct list_head dsa_tree_list;
#endif
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