// SPDX-License-Identifier: GPL-2.0-only
/*
* IEEE 802.1D Generic Attribute Registration Protocol (GARP)
*
* Copyright (c) 2008 Patrick McHardy <[email protected]>
*/
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/rtnetlink.h>
#include <linux/llc.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <net/llc.h>
#include <net/llc_pdu.h>
#include <net/garp.h>
#include <linux/unaligned.h>
static unsigned int garp_join_time __read_mostly = 200;
module_param(garp_join_time, uint, 0644);
MODULE_PARM_DESC(garp_join_time, "Join time in ms (default 200ms)");
MODULE_DESCRIPTION("IEEE 802.1D Generic Attribute Registration Protocol (GARP)");
MODULE_LICENSE("GPL");
static const struct garp_state_trans {
u8 state;
u8 action;
} garp_applicant_state_table[GARP_APPLICANT_MAX + 1][GARP_EVENT_MAX + 1] = {
[GARP_APPLICANT_VA] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_AA,
.action = GARP_ACTION_S_JOIN_IN },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_AA },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VA },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VA },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VA },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_LA },
},
[GARP_APPLICANT_AA] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_QA,
.action = GARP_ACTION_S_JOIN_IN },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QA },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VA },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VA },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VA },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_LA },
},
[GARP_APPLICANT_QA] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QA },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VA },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VA },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_LA },
},
[GARP_APPLICANT_LA] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_VO,
.action = GARP_ACTION_S_LEAVE_EMPTY },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_LA },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_LA },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_LA },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_VA },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_INVALID },
},
[GARP_APPLICANT_VP] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_AA,
.action = GARP_ACTION_S_JOIN_IN },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_AP },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_VO },
},
[GARP_APPLICANT_AP] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_QA,
.action = GARP_ACTION_S_JOIN_IN },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QP },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_AO },
},
[GARP_APPLICANT_QP] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QP },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_QO },
},
[GARP_APPLICANT_VO] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_AO },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_VP },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_INVALID },
},
[GARP_APPLICANT_AO] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QO },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_AP },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_INVALID },
},
[GARP_APPLICANT_QO] = {
[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID },
[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QO },
[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VO },
[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_QP },
[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_INVALID },
},
};
static int garp_attr_cmp(const struct garp_attr *attr,
const void *data, u8 len, u8 type)
{
if (attr->type != type)
return attr->type - type;
if (attr->dlen != len)
return attr->dlen - len;
return memcmp(attr->data, data, len);
}
static struct garp_attr *garp_attr_lookup(const struct garp_applicant *app,
const void *data, u8 len, u8 type)
{
struct rb_node *parent = app->gid.rb_node;
struct garp_attr *attr;
int d;
while (parent) {
attr = rb_entry(parent, struct garp_attr, node);
d = garp_attr_cmp(attr, data, len, type);
if (d > 0)
parent = parent->rb_left;
else if (d < 0)
parent = parent->rb_right;
else
return attr;
}
return NULL;
}
static struct garp_attr *garp_attr_create(struct garp_applicant *app,
const void *data, u8 len, u8 type)
{
struct rb_node *parent = NULL, **p = &app->gid.rb_node;
struct garp_attr *attr;
int d;
while (*p) {
parent = *p;
attr = rb_entry(parent, struct garp_attr, node);
d = garp_attr_cmp(attr, data, len, type);
if (d > 0)
p = &parent->rb_left;
else if (d < 0)
p = &parent->rb_right;
else {
/* The attribute already exists; re-use it. */
return attr;
}
}
attr = kmalloc(sizeof(*attr) + len, GFP_ATOMIC);
if (!attr)
return attr;
attr->state = GARP_APPLICANT_VO;
attr->type = type;
attr->dlen = len;
memcpy(attr->data, data, len);
rb_link_node(&attr->node, parent, p);
rb_insert_color(&attr->node, &app->gid);
return attr;
}
static void garp_attr_destroy(struct garp_applicant *app, struct garp_attr *attr)
{
rb_erase(&attr->node, &app->gid);
kfree(attr);
}
static void garp_attr_destroy_all(struct garp_applicant *app)
{
struct rb_node *node, *next;
struct garp_attr *attr;
for (node = rb_first(&app->gid);
next = node ? rb_next(node) : NULL, node != NULL;
node = next) {
attr = rb_entry(node, struct garp_attr, node);
garp_attr_destroy(app, attr);
}
}
static int garp_pdu_init(struct garp_applicant *app)
{
struct sk_buff *skb;
struct garp_pdu_hdr *gp;
#define LLC_RESERVE sizeof(struct llc_pdu_un)
skb = alloc_skb(app->dev->mtu + LL_RESERVED_SPACE(app->dev),
GFP_ATOMIC);
if (!skb)
return -ENOMEM;
skb->dev = app->dev;
skb->protocol = htons(ETH_P_802_2);
skb_reserve(skb, LL_RESERVED_SPACE(app->dev) + LLC_RESERVE);
gp = __skb_put(skb, sizeof(*gp));
put_unaligned(htons(GARP_PROTOCOL_ID), &gp->protocol);
app->pdu = skb;
return 0;
}
static int garp_pdu_append_end_mark(struct garp_applicant *app)
{
if (skb_tailroom(app->pdu) < sizeof(u8))
return -1;
__skb_put_u8(app->pdu, GARP_END_MARK);
return 0;
}
static void garp_pdu_queue(struct garp_applicant *app)
{
if (!app->pdu)
return;
garp_pdu_append_end_mark(app);
garp_pdu_append_end_mark(app);
llc_pdu_header_init(app->pdu, LLC_PDU_TYPE_U, LLC_SAP_BSPAN,
LLC_SAP_BSPAN, LLC_PDU_CMD);
llc_pdu_init_as_ui_cmd(app->pdu);
llc_mac_hdr_init(app->pdu, app->dev->dev_addr,
app->app->proto.group_address);
skb_queue_tail(&app->queue, app->pdu);
app->pdu = NULL;
}
static void garp_queue_xmit(struct garp_applicant *app)
{
struct sk_buff *skb;
while ((skb = skb_dequeue(&app->queue)))
dev_queue_xmit(skb);
}
static int garp_pdu_append_msg(struct garp_applicant *app, u8 attrtype)
{
struct garp_msg_hdr *gm;
if (skb_tailroom(app->pdu) < sizeof(*gm))
return -1;
gm = __skb_put(app->pdu, sizeof(*gm));
gm->attrtype = attrtype;
garp_cb(app->pdu)->cur_type = attrtype;
return 0;
}
static int garp_pdu_append_attr(struct garp_applicant *app,
const struct garp_attr *attr,
enum garp_attr_event event)
{
struct garp_attr_hdr *ga;
unsigned int len;
int err;
again:
if (!app->pdu) {
err = garp_pdu_init(app);
if (err < 0)
return err;
}
if (garp_cb(app->pdu)->cur_type != attr->type) {
if (garp_cb(app->pdu)->cur_type &&
garp_pdu_append_end_mark(app) < 0)
goto queue;
if (garp_pdu_append_msg(app, attr->type) < 0)
goto queue;
}
len = sizeof(*ga) + attr->dlen;
if (skb_tailroom(app->pdu) < len)
goto queue;
ga = __skb_put(app->pdu, len);
ga->len = len;
ga->event = event;
memcpy(ga->data, attr->data, attr->dlen);
return 0;
queue:
garp_pdu_queue(app);
goto again;
}
static void garp_attr_event(struct garp_applicant *app,
struct garp_attr *attr, enum garp_event event)
{
enum garp_applicant_state state;
state = garp_applicant_state_table[attr->state][event].state;
if (state == GARP_APPLICANT_INVALID)
return;
switch (garp_applicant_state_table[attr->state][event].action) {
case GARP_ACTION_NONE:
break;
case GARP_ACTION_S_JOIN_IN:
/* When appending the attribute fails, don't update state in
* order to retry on next TRANSMIT_PDU event. */
if (garp_pdu_append_attr(app, attr, GARP_JOIN_IN) < 0)
return;
break;
case GARP_ACTION_S_LEAVE_EMPTY:
garp_pdu_append_attr(app, attr, GARP_LEAVE_EMPTY);
/* As a pure applicant, sending a leave message implies that
* the attribute was unregistered and can be destroyed. */
garp_attr_destroy(app, attr);
return;
default:
WARN_ON(1);
}
attr->state = state;
}
int garp_request_join(const struct net_device *dev,
const struct garp_application *appl,
const void *data, u8 len, u8 type)
{
struct garp_port *port = rtnl_dereference(dev->garp_port);
struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
struct garp_attr *attr;
spin_lock_bh(&app->lock);
attr = garp_attr_create(app, data, len, type);
if (!attr) {
spin_unlock_bh(&app->lock);
return -ENOMEM;
}
garp_attr_event(app, attr, GARP_EVENT_REQ_JOIN);
spin_unlock_bh(&app->lock);
return 0;
}
EXPORT_SYMBOL_GPL(garp_request_join);
void garp_request_leave(const struct net_device *dev,
const struct garp_application *appl,
const void *data, u8 len, u8 type)
{
struct garp_port *port = rtnl_dereference(dev->garp_port);
struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
struct garp_attr *attr;
spin_lock_bh(&app->lock);
attr = garp_attr_lookup(app, data, len, type);
if (!attr) {
spin_unlock_bh(&app->lock);
return;
}
garp_attr_event(app, attr, GARP_EVENT_REQ_LEAVE);
spin_unlock_bh(&app->lock);
}
EXPORT_SYMBOL_GPL(garp_request_leave);
static void garp_gid_event(struct garp_applicant *app, enum garp_event event)
{
struct rb_node *node, *next;
struct garp_attr *attr;
for (node = rb_first(&app->gid);
next = node ? rb_next(node) : NULL, node != NULL;
node = next) {
attr = rb_entry(node, struct garp_attr, node);
garp_attr_event(app, attr, event);
}
}
static void garp_join_timer_arm(struct garp_applicant *app)
{
unsigned long delay;
delay = get_random_u32_below(msecs_to_jiffies(garp_join_time));
mod_timer(&app->join_timer, jiffies + delay);
}
static void garp_join_timer(struct timer_list *t)
{
struct garp_applicant *app = from_timer(app, t, join_timer);
spin_lock(&app->lock);
garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
garp_pdu_queue(app);
spin_unlock(&app->lock);
garp_queue_xmit(app);
garp_join_timer_arm(app);
}
static int garp_pdu_parse_end_mark(struct sk_buff *skb)
{
if (!pskb_may_pull(skb, sizeof(u8)))
return -1;
if (*skb->data == GARP_END_MARK) {
skb_pull(skb, sizeof(u8));
return -1;
}
return 0;
}
static int garp_pdu_parse_attr(struct garp_applicant *app, struct sk_buff *skb,
u8 attrtype)
{
const struct garp_attr_hdr *ga;
struct garp_attr *attr;
enum garp_event event;
unsigned int dlen;
if (!pskb_may_pull(skb, sizeof(*ga)))
return -1;
ga = (struct garp_attr_hdr *)skb->data;
if (ga->len < sizeof(*ga))
return -1;
if (!pskb_may_pull(skb, ga->len))
return -1;
skb_pull(skb, ga->len);
dlen = sizeof(*ga) - ga->len;
if (attrtype > app->app->maxattr)
return 0;
switch (ga->event) {
case GARP_LEAVE_ALL:
if (dlen != 0)
return -1;
garp_gid_event(app, GARP_EVENT_R_LEAVE_EMPTY);
return 0;
case GARP_JOIN_EMPTY:
event = GARP_EVENT_R_JOIN_EMPTY;
break;
case GARP_JOIN_IN:
event = GARP_EVENT_R_JOIN_IN;
break;
case GARP_LEAVE_EMPTY:
event = GARP_EVENT_R_LEAVE_EMPTY;
break;
case GARP_EMPTY:
event = GARP_EVENT_R_EMPTY;
break;
default:
return 0;
}
if (dlen == 0)
return -1;
attr = garp_attr_lookup(app, ga->data, dlen, attrtype);
if (attr == NULL)
return 0;
garp_attr_event(app, attr, event);
return 0;
}
static int garp_pdu_parse_msg(struct garp_applicant *app, struct sk_buff *skb)
{
const struct garp_msg_hdr *gm;
if (!pskb_may_pull(skb, sizeof(*gm)))
return -1;
gm = (struct garp_msg_hdr *)skb->data;
if (gm->attrtype == 0)
return -1;
skb_pull(skb, sizeof(*gm));
while (skb->len > 0) {
if (garp_pdu_parse_attr(app, skb, gm->attrtype) < 0)
return -1;
if (garp_pdu_parse_end_mark(skb) < 0)
break;
}
return 0;
}
static void garp_pdu_rcv(const struct stp_proto *proto, struct sk_buff *skb,
struct net_device *dev)
{
struct garp_application *appl = proto->data;
struct garp_port *port;
struct garp_applicant *app;
const struct garp_pdu_hdr *gp;
port = rcu_dereference(dev->garp_port);
if (!port)
goto err;
app = rcu_dereference(port->applicants[appl->type]);
if (!app)
goto err;
if (!pskb_may_pull(skb, sizeof(*gp)))
goto err;
gp = (struct garp_pdu_hdr *)skb->data;
if (get_unaligned(&gp->protocol) != htons(GARP_PROTOCOL_ID))
goto err;
skb_pull(skb, sizeof(*gp));
spin_lock(&app->lock);
while (skb->len > 0) {
if (garp_pdu_parse_msg(app, skb) < 0)
break;
if (garp_pdu_parse_end_mark(skb) < 0)
break;
}
spin_unlock(&app->lock);
err:
kfree_skb(skb);
}
static int garp_init_port(struct net_device *dev)
{
struct garp_port *port;
port = kzalloc(sizeof(*port), GFP_KERNEL);
if (!port)
return -ENOMEM;
rcu_assign_pointer(dev->garp_port, port);
return 0;
}
static void garp_release_port(struct net_device *dev)
{
struct garp_port *port = rtnl_dereference(dev->garp_port);
unsigned int i;
for (i = 0; i <= GARP_APPLICATION_MAX; i++) {
if (rtnl_dereference(port->applicants[i]))
return;
}
RCU_INIT_POINTER(dev->garp_port, NULL);
kfree_rcu(port, rcu);
}
int garp_init_applicant(struct net_device *dev, struct garp_application *appl)
{
struct garp_applicant *app;
int err;
ASSERT_RTNL();
if (!rtnl_dereference(dev->garp_port)) {
err = garp_init_port(dev);
if (err < 0)
goto err1;
}
err = -ENOMEM;
app = kzalloc(sizeof(*app), GFP_KERNEL);
if (!app)
goto err2;
err = dev_mc_add(dev, appl->proto.group_address);
if (err < 0)
goto err3;
app->dev = dev;
app->app = appl;
app->gid = RB_ROOT;
spin_lock_init(&app->lock);
skb_queue_head_init(&app->queue);
rcu_assign_pointer(dev->garp_port->applicants[appl->type], app);
timer_setup(&app->join_timer, garp_join_timer, 0);
garp_join_timer_arm(app);
return 0;
err3:
kfree(app);
err2:
garp_release_port(dev);
err1:
return err;
}
EXPORT_SYMBOL_GPL(garp_init_applicant);
void garp_uninit_applicant(struct net_device *dev, struct garp_application *appl)
{
struct garp_port *port = rtnl_dereference(dev->garp_port);
struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
ASSERT_RTNL();
RCU_INIT_POINTER(port->applicants[appl->type], NULL);
/* Delete timer and generate a final TRANSMIT_PDU event to flush out
* all pending messages before the applicant is gone. */
timer_shutdown_sync(&app->join_timer);
spin_lock_bh(&app->lock);
garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
garp_attr_destroy_all(app);
garp_pdu_queue(app);
spin_unlock_bh(&app->lock);
garp_queue_xmit(app);
dev_mc_del(dev, appl->proto.group_address);
kfree_rcu(app, rcu);
garp_release_port(dev);
}
EXPORT_SYMBOL_GPL(garp_uninit_applicant);
int garp_register_application(struct garp_application *appl)
{
appl->proto.rcv = garp_pdu_rcv;
appl->proto.data = appl;
return stp_proto_register(&appl->proto);
}
EXPORT_SYMBOL_GPL(garp_register_application);
void garp_unregister_application(struct garp_application *appl)
{
stp_proto_unregister(&appl->proto);
}
EXPORT_SYMBOL_GPL(garp_unregister_application);
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