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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 | SVL | SWITCH_ID | SUBVLAN | 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.
*
* SVL/SUBVLAN - { VID[9], VID[5:4] }:
* Sub-VLAN encoding. Valid only when DIR indicates an RX VLAN.
* * 0 (0b000): Field does not encode a sub-VLAN, either because
* received traffic is untagged, PVID-tagged or because a second
* VLAN tag is present after this tag and not inside of it.
* * 1 (0b001): Received traffic is tagged with a VID value private
* to the host. This field encodes the index in the host's lookup
* table through which the value of the ingress VLAN ID can be
* recovered.
* * 2 (0b010): Field encodes a sub-VLAN.
* ...
* * 7 (0b111): Field encodes a sub-VLAN.
* When DIR indicates a TX VLAN, SUBVLAN must be transmitted as zero
* (by the host) and ignored on receive (by the switch).
*
* SWITCH_ID - VID[8:6]:
* Index of switch within DSA tree. Must be between 0 and 7.
*
* 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_SUBVLAN_HI_SHIFT 9
#define DSA_8021Q_SUBVLAN_HI_MASK GENMASK(9, 9)
#define DSA_8021Q_SUBVLAN_LO_SHIFT 4
#define DSA_8021Q_SUBVLAN_LO_MASK GENMASK(5, 4)
#define DSA_8021Q_SUBVLAN_HI(x) (((x) & GENMASK(2, 2)) >> 2)
#define DSA_8021Q_SUBVLAN_LO(x) ((x) & GENMASK(1, 0))
#define DSA_8021Q_SUBVLAN(x) \
(((DSA_8021Q_SUBVLAN_LO(x) << DSA_8021Q_SUBVLAN_LO_SHIFT) & \
DSA_8021Q_SUBVLAN_LO_MASK) | \
((DSA_8021Q_SUBVLAN_HI(x) << DSA_8021Q_SUBVLAN_HI_SHIFT) & \
DSA_8021Q_SUBVLAN_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)
/* 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);
u16 dsa_8021q_rx_vid_subvlan(struct dsa_switch *ds, int port, u16 subvlan)
{
return DSA_8021Q_DIR_RX | DSA_8021Q_SWITCH_ID(ds->index) |
DSA_8021Q_PORT(port) | DSA_8021Q_SUBVLAN(subvlan);
}
EXPORT_SYMBOL_GPL(dsa_8021q_rx_vid_subvlan);
/* 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);
/* Returns the decoded subvlan from the RX VID. */
u16 dsa_8021q_rx_subvlan(u16 vid)
{
u16 svl_hi, svl_lo;
svl_hi = (vid & DSA_8021Q_SUBVLAN_HI_MASK) >>
DSA_8021Q_SUBVLAN_HI_SHIFT;
svl_lo = (vid & DSA_8021Q_SUBVLAN_LO_MASK) >>
DSA_8021Q_SUBVLAN_LO_SHIFT;
return (svl_hi << 2) | svl_lo;
}
EXPORT_SYMBOL_GPL(dsa_8021q_rx_subvlan);
bool vid_is_dsa_8021q(u16 vid)
{
return ((vid & DSA_8021Q_DIR_MASK) == DSA_8021Q_DIR_RX ||
(vid & DSA_8021Q_DIR_MASK) == DSA_8021Q_DIR_TX);
}
EXPORT_SYMBOL_GPL(vid_is_dsa_8021q);
/* If @enabled is true, installs @vid with @flags into the switch port's HW
* filter.
* If @enabled is false, deletes @vid (ignores @flags) from the port. Had the
* user explicitly configured this @vid through the bridge core, then the @vid
* is installed again, but this time with the flags from the bridge layer.
*/
static int dsa_8021q_vid_apply(struct dsa_8021q_context *ctx, int port, u16 vid,
u16 flags, bool enabled)
{
struct dsa_port *dp = dsa_to_port(ctx->ds, port);
if (enabled)
return ctx->ops->vlan_add(ctx->ds, dp->index, vid, flags);
return ctx->ops->vlan_del(ctx->ds, dp->index, vid);
}
/* 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).
* By the way - just because we're installing the same VID in multiple
* switch ports doesn't mean that they'll start to talk to one another, even
* while not bridged: the final forwarding decision is still an AND between
* the L2 forwarding information (which is limiting forwarding in this case)
* and the VLAN-based restrictions (of which there are none in this case,
* since all ports are members).
* - 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, 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 int dsa_8021q_setup_port(struct dsa_8021q_context *ctx, int port,
bool enabled)
{
int upstream = dsa_upstream_port(ctx->ds, port);
u16 rx_vid = dsa_8021q_rx_vid(ctx->ds, port);
u16 tx_vid = dsa_8021q_tx_vid(ctx->ds, port);
struct net_device *master;
int i, err, subvlan;
/* The CPU port is implicitly configured by
* configuring the front-panel ports
*/
if (!dsa_is_user_port(ctx->ds, port))
return 0;
master = dsa_to_port(ctx->ds, port)->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.
*/
for (i = 0; i < ctx->ds->num_ports; i++) {
u16 flags;
if (i == upstream)
continue;
else if (i == port)
/* The RX VID is pvid on this port */
flags = BRIDGE_VLAN_INFO_UNTAGGED |
BRIDGE_VLAN_INFO_PVID;
else
/* The RX VID is a regular VLAN on all others */
flags = BRIDGE_VLAN_INFO_UNTAGGED;
err = dsa_8021q_vid_apply(ctx, i, rx_vid, flags, enabled);
if (err) {
dev_err(ctx->ds->dev,
"Failed to apply RX VID %d to port %d: %d\n",
rx_vid, port, err);
return err;
}
}
/* CPU port needs to see this port's RX VID
* as tagged egress.
*/
err = dsa_8021q_vid_apply(ctx, upstream, rx_vid, 0, enabled);
if (err) {
dev_err(ctx->ds->dev,
"Failed to apply RX VID %d to port %d: %d\n",
rx_vid, port, err);
return err;
}
/* Add to the master's RX filter not only @rx_vid, but in fact
* the entire subvlan range, just in case this DSA switch might
* want to use sub-VLANs.
*/
for (subvlan = 0; subvlan < DSA_8021Q_N_SUBVLAN; subvlan++) {
u16 vid = dsa_8021q_rx_vid_subvlan(ctx->ds, port, subvlan);
if (enabled)
vlan_vid_add(master, ctx->proto, vid);
else
vlan_vid_del(master, ctx->proto, vid);
}
/* Finally apply the TX VID on this port and on the CPU port */
err = dsa_8021q_vid_apply(ctx, port, tx_vid, BRIDGE_VLAN_INFO_UNTAGGED,
enabled);
if (err) {
dev_err(ctx->ds->dev,
"Failed to apply TX VID %d on port %d: %d\n",
tx_vid, port, err);
return err;
}
err = dsa_8021q_vid_apply(ctx, upstream, tx_vid, 0, enabled);
if (err) {
dev_err(ctx->ds->dev,
"Failed to apply TX VID %d on port %d: %d\n",
tx_vid, upstream, err);
return err;
}
return err;
}
int dsa_8021q_setup(struct dsa_8021q_context *ctx, bool enabled)
{
int rc, port;
ASSERT_RTNL();
for (port = 0; port < ctx->ds->num_ports; port++) {
rc = dsa_8021q_setup_port(ctx, port, enabled);
if (rc < 0) {
dev_err(ctx->ds->dev,
"Failed to setup VLAN tagging for port %d: %d\n",
port, rc);
return rc;
}
}
return 0;
}
EXPORT_SYMBOL_GPL(dsa_8021q_setup);
static int dsa_8021q_crosschip_link_apply(struct dsa_8021q_context *ctx,
int port,
struct dsa_8021q_context *other_ctx,
int other_port, bool enabled)
{
u16 rx_vid = dsa_8021q_rx_vid(ctx->ds, port);
/* @rx_vid of local @ds port @port goes to @other_port of
* @other_ds
*/
return dsa_8021q_vid_apply(other_ctx, other_port, rx_vid,
BRIDGE_VLAN_INFO_UNTAGGED, enabled);
}
static int dsa_8021q_crosschip_link_add(struct dsa_8021q_context *ctx, int port,
struct dsa_8021q_context *other_ctx,
int other_port)
{
struct dsa_8021q_crosschip_link *c;
list_for_each_entry(c, &ctx->crosschip_links, list) {
if (c->port == port && c->other_ctx == other_ctx &&
c->other_port == other_port) {
refcount_inc(&c->refcount);
return 0;
}
}
dev_dbg(ctx->ds->dev,
"adding crosschip link from port %d to %s port %d\n",
port, dev_name(other_ctx->ds->dev), other_port);
c = kzalloc(sizeof(*c), GFP_KERNEL);
if (!c)
return -ENOMEM;
c->port = port;
c->other_ctx = other_ctx;
c->other_port = other_port;
refcount_set(&c->refcount, 1);
list_add(&c->list, &ctx->crosschip_links);
return 0;
}
static void dsa_8021q_crosschip_link_del(struct dsa_8021q_context *ctx,
struct dsa_8021q_crosschip_link *c,
bool *keep)
{
*keep = !refcount_dec_and_test(&c->refcount);
if (*keep)
return;
dev_dbg(ctx->ds->dev,
"deleting crosschip link from port %d to %s port %d\n",
c->port, dev_name(c->other_ctx->ds->dev), c->other_port);
list_del(&c->list);
kfree(c);
}
/* Make traffic from local port @port be received by remote port @other_port.
* This means that our @rx_vid needs to be installed on @other_ds's upstream
* and user ports. The user ports should be egress-untagged so that they can
* pop the dsa_8021q VLAN. But the @other_upstream can be either egress-tagged
* or untagged: it doesn't matter, since it should never egress a frame having
* our @rx_vid.
*/
int dsa_8021q_crosschip_bridge_join(struct dsa_8021q_context *ctx, int port,
struct dsa_8021q_context *other_ctx,
int other_port)
{
/* @other_upstream is how @other_ds reaches us. If we are part
* of disjoint trees, then we are probably connected through
* our CPU ports. If we're part of the same tree though, we should
* probably use dsa_towards_port.
*/
int other_upstream = dsa_upstream_port(other_ctx->ds, other_port);
int rc;
rc = dsa_8021q_crosschip_link_add(ctx, port, other_ctx, other_port);
if (rc)
return rc;
rc = dsa_8021q_crosschip_link_apply(ctx, port, other_ctx,
other_port, true);
if (rc)
return rc;
rc = dsa_8021q_crosschip_link_add(ctx, port, other_ctx, other_upstream);
if (rc)
return rc;
return dsa_8021q_crosschip_link_apply(ctx, port, other_ctx,
other_upstream, true);
}
EXPORT_SYMBOL_GPL(dsa_8021q_crosschip_bridge_join);
int dsa_8021q_crosschip_bridge_leave(struct dsa_8021q_context *ctx, int port,
struct dsa_8021q_context *other_ctx,
int other_port)
{
int other_upstream = dsa_upstream_port(other_ctx->ds, other_port);
struct dsa_8021q_crosschip_link *c, *n;
list_for_each_entry_safe(c, n, &ctx->crosschip_links, list) {
if (c->port == port && c->other_ctx == other_ctx &&
(c->other_port == other_port ||
c->other_port == other_upstream)) {
struct dsa_8021q_context *other_ctx = c->other_ctx;
int other_port = c->other_port;
bool keep;
int rc;
dsa_8021q_crosschip_link_del(ctx, c, &keep);
if (keep)
continue;
rc = dsa_8021q_crosschip_link_apply(ctx, port,
other_ctx,
other_port,
false);
if (rc)
return rc;
}
}
return 0;
}
EXPORT_SYMBOL_GPL(dsa_8021q_crosschip_bridge_leave);
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);
MODULE_LICENSE("GPL v2");