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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2019, Vladimir Oltean <olteanv@gmail.com>
*
* This module is not a complete tagger implementation. It only provides
* primitives for taggers that rely on 802.1Q VLAN tags to use. The
* dsa_8021q_netdev_ops is registered for API compliance and not used
* directly by callers.
*/
#include <linux/if_bridge.h>
#include <linux/if_vlan.h>
#include <linux/dsa/8021q.h>
#include "dsa_priv.h"
/* Binary structure of the fake 12-bit VID field (when the TPID is
* ETH_P_DSA_8021Q):
*
* | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
* +-----------+-----+-----------------+-----------+-----------------------+
* | DIR | VBID| SWITCH_ID | VBID | PORT |
* +-----------+-----+-----------------+-----------+-----------------------+
*
* DIR - VID[11:10]:
* Direction flags.
* * 1 (0b01) for RX VLAN,
* * 2 (0b10) for TX VLAN.
* These values make the special VIDs of 0, 1 and 4095 to be left
* unused by this coding scheme.
*
* SWITCH_ID - VID[8:6]:
* Index of switch within DSA tree. Must be between 0 and 7.
*
* VBID - { VID[9], VID[5:4] }:
* Virtual bridge ID. If between 1 and 7, packet targets the broadcast
* domain of a bridge. If transmitted as zero, packet targets a single
* port. Field only valid on transmit, must be ignored on receive.
*
* PORT - VID[3:0]:
* Index of switch port. Must be between 0 and 15.
*/
#define DSA_8021Q_DIR_SHIFT 10
#define DSA_8021Q_DIR_MASK GENMASK(11, 10)
#define DSA_8021Q_DIR(x) (((x) << DSA_8021Q_DIR_SHIFT) & \
DSA_8021Q_DIR_MASK)
#define DSA_8021Q_DIR_RX DSA_8021Q_DIR(1)
#define DSA_8021Q_DIR_TX DSA_8021Q_DIR(2)
#define DSA_8021Q_SWITCH_ID_SHIFT 6
#define DSA_8021Q_SWITCH_ID_MASK GENMASK(8, 6)
#define DSA_8021Q_SWITCH_ID(x) (((x) << DSA_8021Q_SWITCH_ID_SHIFT) & \
DSA_8021Q_SWITCH_ID_MASK)
#define DSA_8021Q_VBID_HI_SHIFT 9
#define DSA_8021Q_VBID_HI_MASK GENMASK(9, 9)
#define DSA_8021Q_VBID_LO_SHIFT 4
#define DSA_8021Q_VBID_LO_MASK GENMASK(5, 4)
#define DSA_8021Q_VBID_HI(x) (((x) & GENMASK(2, 2)) >> 2)
#define DSA_8021Q_VBID_LO(x) ((x) & GENMASK(1, 0))
#define DSA_8021Q_VBID(x) \
(((DSA_8021Q_VBID_LO(x) << DSA_8021Q_VBID_LO_SHIFT) & \
DSA_8021Q_VBID_LO_MASK) | \
((DSA_8021Q_VBID_HI(x) << DSA_8021Q_VBID_HI_SHIFT) & \
DSA_8021Q_VBID_HI_MASK))
#define DSA_8021Q_PORT_SHIFT 0
#define DSA_8021Q_PORT_MASK GENMASK(3, 0)
#define DSA_8021Q_PORT(x) (((x) << DSA_8021Q_PORT_SHIFT) & \
DSA_8021Q_PORT_MASK)
u16 dsa_8021q_bridge_tx_fwd_offload_vid(int bridge_num)
{
/* The VBID value of 0 is reserved for precise TX */
return DSA_8021Q_DIR_TX | DSA_8021Q_VBID(bridge_num + 1);
}
EXPORT_SYMBOL_GPL(dsa_8021q_bridge_tx_fwd_offload_vid);
/* Returns the VID to be inserted into the frame from xmit for switch steering
* instructions on egress. Encodes switch ID and port ID.
*/
u16 dsa_8021q_tx_vid(struct dsa_switch *ds, int port)
{
return DSA_8021Q_DIR_TX | DSA_8021Q_SWITCH_ID(ds->index) |
DSA_8021Q_PORT(port);
}
EXPORT_SYMBOL_GPL(dsa_8021q_tx_vid);
/* Returns the VID that will be installed as pvid for this switch port, sent as
* tagged egress towards the CPU port and decoded by the rcv function.
*/
u16 dsa_8021q_rx_vid(struct dsa_switch *ds, int port)
{
return DSA_8021Q_DIR_RX | DSA_8021Q_SWITCH_ID(ds->index) |
DSA_8021Q_PORT(port);
}
EXPORT_SYMBOL_GPL(dsa_8021q_rx_vid);
/* Returns the decoded switch ID from the RX VID. */
int dsa_8021q_rx_switch_id(u16 vid)
{
return (vid & DSA_8021Q_SWITCH_ID_MASK) >> DSA_8021Q_SWITCH_ID_SHIFT;
}
EXPORT_SYMBOL_GPL(dsa_8021q_rx_switch_id);
/* Returns the decoded port ID from the RX VID. */
int dsa_8021q_rx_source_port(u16 vid)
{
return (vid & DSA_8021Q_PORT_MASK) >> DSA_8021Q_PORT_SHIFT;
}
EXPORT_SYMBOL_GPL(dsa_8021q_rx_source_port);
bool vid_is_dsa_8021q_rxvlan(u16 vid)
{
return (vid & DSA_8021Q_DIR_MASK) == DSA_8021Q_DIR_RX;
}
EXPORT_SYMBOL_GPL(vid_is_dsa_8021q_rxvlan);
bool vid_is_dsa_8021q_txvlan(u16 vid)
{
return (vid & DSA_8021Q_DIR_MASK) == DSA_8021Q_DIR_TX;
}
EXPORT_SYMBOL_GPL(vid_is_dsa_8021q_txvlan);
bool vid_is_dsa_8021q(u16 vid)
{
return vid_is_dsa_8021q_rxvlan(vid) || vid_is_dsa_8021q_txvlan(vid);
}
EXPORT_SYMBOL_GPL(vid_is_dsa_8021q);
static struct dsa_tag_8021q_vlan *
dsa_tag_8021q_vlan_find(struct dsa_8021q_context *ctx, int port, u16 vid)
{
struct dsa_tag_8021q_vlan *v;
list_for_each_entry(v, &ctx->vlans, list)
if (v->vid == vid && v->port == port)
return v;
return NULL;
}
static int dsa_switch_do_tag_8021q_vlan_add(struct dsa_switch *ds, int port,
u16 vid, u16 flags)
{
struct dsa_8021q_context *ctx = ds->tag_8021q_ctx;
struct dsa_port *dp = dsa_to_port(ds, port);
struct dsa_tag_8021q_vlan *v;
int err;
/* No need to bother with refcounting for user ports */
if (!(dsa_port_is_cpu(dp) || dsa_port_is_dsa(dp)))
return ds->ops->tag_8021q_vlan_add(ds, port, vid, flags);
v = dsa_tag_8021q_vlan_find(ctx, port, vid);
if (v) {
refcount_inc(&v->refcount);
return 0;
}
v = kzalloc(sizeof(*v), GFP_KERNEL);
if (!v)
return -ENOMEM;
err = ds->ops->tag_8021q_vlan_add(ds, port, vid, flags);
if (err) {
kfree(v);
return err;
}
v->vid = vid;
v->port = port;
refcount_set(&v->refcount, 1);
list_add_tail(&v->list, &ctx->vlans);
return 0;
}
static int dsa_switch_do_tag_8021q_vlan_del(struct dsa_switch *ds, int port,
u16 vid)
{
struct dsa_8021q_context *ctx = ds->tag_8021q_ctx;
struct dsa_port *dp = dsa_to_port(ds, port);
struct dsa_tag_8021q_vlan *v;
int err;
/* No need to bother with refcounting for user ports */
if (!(dsa_port_is_cpu(dp) || dsa_port_is_dsa(dp)))
return ds->ops->tag_8021q_vlan_del(ds, port, vid);
v = dsa_tag_8021q_vlan_find(ctx, port, vid);
if (!v)
return -ENOENT;
if (!refcount_dec_and_test(&v->refcount))
return 0;
err = ds->ops->tag_8021q_vlan_del(ds, port, vid);
if (err) {
refcount_inc(&v->refcount);
return err;
}
list_del(&v->list);
kfree(v);
return 0;
}
static bool
dsa_switch_tag_8021q_vlan_match(struct dsa_switch *ds, int port,
struct dsa_notifier_tag_8021q_vlan_info *info)
{
if (dsa_is_dsa_port(ds, port) || dsa_is_cpu_port(ds, port))
return true;
if (ds->dst->index == info->tree_index && ds->index == info->sw_index)
return port == info->port;
return false;
}
int dsa_switch_tag_8021q_vlan_add(struct dsa_switch *ds,
struct dsa_notifier_tag_8021q_vlan_info *info)
{
int port, err;
/* Since we use dsa_broadcast(), there might be other switches in other
* trees which don't support tag_8021q, so don't return an error.
* Or they might even support tag_8021q but have not registered yet to
* use it (maybe they use another tagger currently).
*/
if (!ds->ops->tag_8021q_vlan_add || !ds->tag_8021q_ctx)
return 0;
for (port = 0; port < ds->num_ports; port++) {
if (dsa_switch_tag_8021q_vlan_match(ds, port, info)) {
u16 flags = 0;
if (dsa_is_user_port(ds, port))
flags |= BRIDGE_VLAN_INFO_UNTAGGED;
if (vid_is_dsa_8021q_rxvlan(info->vid) &&
dsa_8021q_rx_switch_id(info->vid) == ds->index &&
dsa_8021q_rx_source_port(info->vid) == port)
flags |= BRIDGE_VLAN_INFO_PVID;
err = dsa_switch_do_tag_8021q_vlan_add(ds, port,
info->vid,
flags);
if (err)
return err;
}
}
return 0;
}
int dsa_switch_tag_8021q_vlan_del(struct dsa_switch *ds,
struct dsa_notifier_tag_8021q_vlan_info *info)
{
int port, err;
if (!ds->ops->tag_8021q_vlan_del || !ds->tag_8021q_ctx)
return 0;
for (port = 0; port < ds->num_ports; port++) {
if (dsa_switch_tag_8021q_vlan_match(ds, port, info)) {
err = dsa_switch_do_tag_8021q_vlan_del(ds, port,
info->vid);
if (err)
return err;
}
}
return 0;
}
/* RX VLAN tagging (left) and TX VLAN tagging (right) setup shown for a single
* front-panel switch port (here swp0).
*
* Port identification through VLAN (802.1Q) tags has different requirements
* for it to work effectively:
* - On RX (ingress from network): each front-panel port must have a pvid
* that uniquely identifies it, and the egress of this pvid must be tagged
* towards the CPU port, so that software can recover the source port based
* on the VID in the frame. But this would only work for standalone ports;
* if bridged, this VLAN setup would break autonomous forwarding and would
* force all switched traffic to pass through the CPU. So we must also make
* the other front-panel ports members of this VID we're adding, albeit
* we're not making it their PVID (they'll still have their own).
* - On TX (ingress from CPU and towards network) we are faced with a problem.
* If we were to tag traffic (from within DSA) with the port's pvid, all
* would be well, assuming the switch ports were standalone. Frames would
* have no choice but to be directed towards the correct front-panel port.
* But because we also want the RX VLAN to not break bridging, then
* inevitably that means that we have to give them a choice (of what
* front-panel port to go out on), and therefore we cannot steer traffic
* based on the RX VID. So what we do is simply install one more VID on the
* front-panel and CPU ports, and profit off of the fact that steering will
* work just by virtue of the fact that there is only one other port that's
* a member of the VID we're tagging the traffic with - the desired one.
*
* So at the end, each front-panel port will have one RX VID (also the PVID),
* the RX VID of all other front-panel ports that are in the same bridge, and
* one TX VID. Whereas the CPU port will have the RX and TX VIDs of all
* front-panel ports, and on top of that, is also tagged-input and
* tagged-output (VLAN trunk).
*
* CPU port CPU port
* +-------------+-----+-------------+ +-------------+-----+-------------+
* | RX VID | | | | TX VID | | |
* | of swp0 | | | | of swp0 | | |
* | +-----+ | | +-----+ |
* | ^ T | | | Tagged |
* | | | | | ingress |
* | +-------+---+---+-------+ | | +-----------+ |
* | | | | | | | | Untagged |
* | | U v U v U v | | v egress |
* | +-----+ +-----+ +-----+ +-----+ | | +-----+ +-----+ +-----+ +-----+ |
* | | | | | | | | | | | | | | | | | | | |
* | |PVID | | | | | | | | | | | | | | | | | |
* +-+-----+-+-----+-+-----+-+-----+-+ +-+-----+-+-----+-+-----+-+-----+-+
* swp0 swp1 swp2 swp3 swp0 swp1 swp2 swp3
*/
static bool dsa_tag_8021q_bridge_match(struct dsa_switch *ds, int port,
struct dsa_notifier_bridge_info *info)
{
struct dsa_port *dp = dsa_to_port(ds, port);
/* Don't match on self */
if (ds->dst->index == info->tree_index &&
ds->index == info->sw_index &&
port == info->port)
return false;
if (dsa_port_is_user(dp))
return dp->bridge_dev == info->br;
return false;
}
int dsa_tag_8021q_bridge_join(struct dsa_switch *ds,
struct dsa_notifier_bridge_info *info)
{
struct dsa_switch *targeted_ds;
struct dsa_port *targeted_dp;
u16 targeted_rx_vid;
int err, port;
if (!ds->tag_8021q_ctx)
return 0;
targeted_ds = dsa_switch_find(info->tree_index, info->sw_index);
targeted_dp = dsa_to_port(targeted_ds, info->port);
targeted_rx_vid = dsa_8021q_rx_vid(targeted_ds, info->port);
for (port = 0; port < ds->num_ports; port++) {
struct dsa_port *dp = dsa_to_port(ds, port);
u16 rx_vid = dsa_8021q_rx_vid(ds, port);
if (!dsa_tag_8021q_bridge_match(ds, port, info))
continue;
/* Install the RX VID of the targeted port in our VLAN table */
err = dsa_port_tag_8021q_vlan_add(dp, targeted_rx_vid, true);
if (err)
return err;
/* Install our RX VID into the targeted port's VLAN table */
err = dsa_port_tag_8021q_vlan_add(targeted_dp, rx_vid, true);
if (err)
return err;
}
return 0;
}
int dsa_tag_8021q_bridge_leave(struct dsa_switch *ds,
struct dsa_notifier_bridge_info *info)
{
struct dsa_switch *targeted_ds;
struct dsa_port *targeted_dp;
u16 targeted_rx_vid;
int port;
if (!ds->tag_8021q_ctx)
return 0;
targeted_ds = dsa_switch_find(info->tree_index, info->sw_index);
targeted_dp = dsa_to_port(targeted_ds, info->port);
targeted_rx_vid = dsa_8021q_rx_vid(targeted_ds, info->port);
for (port = 0; port < ds->num_ports; port++) {
struct dsa_port *dp = dsa_to_port(ds, port);
u16 rx_vid = dsa_8021q_rx_vid(ds, port);
if (!dsa_tag_8021q_bridge_match(ds, port, info))
continue;
/* Remove the RX VID of the targeted port from our VLAN table */
dsa_port_tag_8021q_vlan_del(dp, targeted_rx_vid, true);
/* Remove our RX VID from the targeted port's VLAN table */
dsa_port_tag_8021q_vlan_del(targeted_dp, rx_vid, true);
}
return 0;
}
int dsa_tag_8021q_bridge_tx_fwd_offload(struct dsa_switch *ds, int port,
struct net_device *br,
int bridge_num)
{
u16 tx_vid = dsa_8021q_bridge_tx_fwd_offload_vid(bridge_num);
return dsa_port_tag_8021q_vlan_add(dsa_to_port(ds, port), tx_vid,
true);
}
EXPORT_SYMBOL_GPL(dsa_tag_8021q_bridge_tx_fwd_offload);
void dsa_tag_8021q_bridge_tx_fwd_unoffload(struct dsa_switch *ds, int port,
struct net_device *br,
int bridge_num)
{
u16 tx_vid = dsa_8021q_bridge_tx_fwd_offload_vid(bridge_num);
dsa_port_tag_8021q_vlan_del(dsa_to_port(ds, port), tx_vid, true);
}
EXPORT_SYMBOL_GPL(dsa_tag_8021q_bridge_tx_fwd_unoffload);
/* Set up a port's tag_8021q RX and TX VLAN for standalone mode operation */
static int dsa_tag_8021q_port_setup(struct dsa_switch *ds, int port)
{
struct dsa_8021q_context *ctx = ds->tag_8021q_ctx;
struct dsa_port *dp = dsa_to_port(ds, port);
u16 rx_vid = dsa_8021q_rx_vid(ds, port);
u16 tx_vid = dsa_8021q_tx_vid(ds, port);
struct net_device *master;
int err;
/* The CPU port is implicitly configured by
* configuring the front-panel ports
*/
if (!dsa_port_is_user(dp))
return 0;
master = dp->cpu_dp->master;
/* Add this user port's RX VID to the membership list of all others
* (including itself). This is so that bridging will not be hindered.
* L2 forwarding rules still take precedence when there are no VLAN
* restrictions, so there are no concerns about leaking traffic.
*/
err = dsa_port_tag_8021q_vlan_add(dp, rx_vid, false);
if (err) {
dev_err(ds->dev,
"Failed to apply RX VID %d to port %d: %pe\n",
rx_vid, port, ERR_PTR(err));
return err;
}
/* Add @rx_vid to the master's RX filter. */
vlan_vid_add(master, ctx->proto, rx_vid);
/* Finally apply the TX VID on this port and on the CPU port */
err = dsa_port_tag_8021q_vlan_add(dp, tx_vid, false);
if (err) {
dev_err(ds->dev,
"Failed to apply TX VID %d on port %d: %pe\n",
tx_vid, port, ERR_PTR(err));
return err;
}
return err;
}
static void dsa_tag_8021q_port_teardown(struct dsa_switch *ds, int port)
{
struct dsa_8021q_context *ctx = ds->tag_8021q_ctx;
struct dsa_port *dp = dsa_to_port(ds, port);
u16 rx_vid = dsa_8021q_rx_vid(ds, port);
u16 tx_vid = dsa_8021q_tx_vid(ds, port);
struct net_device *master;
/* The CPU port is implicitly configured by
* configuring the front-panel ports
*/
if (!dsa_port_is_user(dp))
return;
master = dp->cpu_dp->master;
dsa_port_tag_8021q_vlan_del(dp, rx_vid, false);
vlan_vid_del(master, ctx->proto, rx_vid);
dsa_port_tag_8021q_vlan_del(dp, tx_vid, false);
}
static int dsa_tag_8021q_setup(struct dsa_switch *ds)
{
int err, port;
ASSERT_RTNL();
for (port = 0; port < ds->num_ports; port++) {
err = dsa_tag_8021q_port_setup(ds, port);
if (err < 0) {
dev_err(ds->dev,
"Failed to setup VLAN tagging for port %d: %pe\n",
port, ERR_PTR(err));
return err;
}
}
return 0;
}
static void dsa_tag_8021q_teardown(struct dsa_switch *ds)
{
int port;
ASSERT_RTNL();
for (port = 0; port < ds->num_ports; port++)
dsa_tag_8021q_port_teardown(ds, port);
}
int dsa_tag_8021q_register(struct dsa_switch *ds, __be16 proto)
{
struct dsa_8021q_context *ctx;
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
ctx->proto = proto;
ctx->ds = ds;
INIT_LIST_HEAD(&ctx->vlans);
ds->tag_8021q_ctx = ctx;
return dsa_tag_8021q_setup(ds);
}
EXPORT_SYMBOL_GPL(dsa_tag_8021q_register);
void dsa_tag_8021q_unregister(struct dsa_switch *ds)
{
struct dsa_8021q_context *ctx = ds->tag_8021q_ctx;
struct dsa_tag_8021q_vlan *v, *n;
dsa_tag_8021q_teardown(ds);
list_for_each_entry_safe(v, n, &ctx->vlans, list) {
list_del(&v->list);
kfree(v);
}
ds->tag_8021q_ctx = NULL;
kfree(ctx);
}
EXPORT_SYMBOL_GPL(dsa_tag_8021q_unregister);
struct sk_buff *dsa_8021q_xmit(struct sk_buff *skb, struct net_device *netdev,
u16 tpid, u16 tci)
{
/* skb->data points at skb_mac_header, which
* is fine for vlan_insert_tag.
*/
return vlan_insert_tag(skb, htons(tpid), tci);
}
EXPORT_SYMBOL_GPL(dsa_8021q_xmit);
void dsa_8021q_rcv(struct sk_buff *skb, int *source_port, int *switch_id)
{
u16 vid, tci;
skb_push_rcsum(skb, ETH_HLEN);
if (skb_vlan_tag_present(skb)) {
tci = skb_vlan_tag_get(skb);
__vlan_hwaccel_clear_tag(skb);
} else {
__skb_vlan_pop(skb, &tci);
}
skb_pull_rcsum(skb, ETH_HLEN);
vid = tci & VLAN_VID_MASK;
*source_port = dsa_8021q_rx_source_port(vid);
*switch_id = dsa_8021q_rx_switch_id(vid);
skb->priority = (tci & VLAN_PRIO_MASK) >> VLAN_PRIO_SHIFT;
}
EXPORT_SYMBOL_GPL(dsa_8021q_rcv);