[mirror_ubuntu-hirsute-kernel.git] / net / 802 / garp.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 *	IEEE 802.1D Generic Attribute Registration Protocol (GARP)
 *
 *	Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
 */
#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 <asm/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_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 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 = (u64)msecs_to_jiffies(garp_join_time) * prandom_u32() >> 32;
	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. */
	del_timer_sync(&app->join_timer);

	spin_lock_bh(&app->lock);
	garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
	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);
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
eca9ebac PM	2	/*
	3	* IEEE 802.1D Generic Attribute Registration Protocol (GARP)
	4	*
	5	* Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
eca9ebac PM	6	*/
	7	#include <linux/kernel.h>
	8	#include <linux/timer.h>
	9	#include <linux/skbuff.h>
	10	#include <linux/netdevice.h>
	11	#include <linux/etherdevice.h>
	12	#include <linux/rtnetlink.h>
	13	#include <linux/llc.h>
5a0e3ad6	14	#include <linux/slab.h>
3a9a231d	15	#include <linux/module.h>
eca9ebac PM	16	#include <net/llc.h>
	17	#include <net/llc_pdu.h>
	18	#include <net/garp.h>
	19	#include <asm/unaligned.h>
	20
	21	static unsigned int garp_join_time __read_mostly = 200;
	22	module_param(garp_join_time, uint, 0644);
	23	MODULE_PARM_DESC(garp_join_time, "Join time in ms (default 200ms)");
	24	MODULE_LICENSE("GPL");
	25
	26	static const struct garp_state_trans {
	27	u8 state;
	28	u8 action;
	29	} garp_applicant_state_table[GARP_APPLICANT_MAX + 1][GARP_EVENT_MAX + 1] = {
	30	[GARP_APPLICANT_VA] = {
	31	[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_AA,
	32	.action = GARP_ACTION_S_JOIN_IN },
	33	[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_AA },
	34	[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VA },
	35	[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VA },
	36	[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VA },
	37	[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP },
	38	[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID },
	39	[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_LA },
	40	},
	41	[GARP_APPLICANT_AA] = {
	42	[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_QA,
	43	.action = GARP_ACTION_S_JOIN_IN },
	44	[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QA },
	45	[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VA },
	46	[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VA },
	47	[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VA },
	48	[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP },
	49	[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID },
	50	[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_LA },
	51	},
	52	[GARP_APPLICANT_QA] = {
	53	[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID },
	54	[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QA },
	55	[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VA },
	56	[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VA },
	57	[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VP },
	58	[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP },
	59	[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID },
	60	[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_LA },
	61	},
	62	[GARP_APPLICANT_LA] = {
	63	[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_VO,
	64	.action = GARP_ACTION_S_LEAVE_EMPTY },
	65	[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_LA },
	66	[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VO },
	67	[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_LA },
	68	[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_LA },
	69	[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VO },
	70	[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_VA },
	71	[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_INVALID },
	72	},
	73	[GARP_APPLICANT_VP] = {
	74	[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_AA,
	75	.action = GARP_ACTION_S_JOIN_IN },
	76	[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_AP },
	77	[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VP },
	78	[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VP },
	79	[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VP },
80	[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP },
81	[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID },
82	[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_VO },
83	},
84	[GARP_APPLICANT_AP] = {
85	[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_QA,
86	.action = GARP_ACTION_S_JOIN_IN },
87	[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QP },
88	[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VP },
89	[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VP },
90	[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VP },
91	[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP },
92	[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID },
93	[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_AO },
94	},
95	[GARP_APPLICANT_QP] = {
96	[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID },
97	[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QP },
98	[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VP },
99	[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VP },
100	[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VP },
101	[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VP },
102	[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_INVALID },
103	[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_QO },
104	},
105	[GARP_APPLICANT_VO] = {
106	[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID },
107	[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_AO },
108	[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VO },
109	[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VO },
110	[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VO },
111	[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VO },
112	[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_VP },
113	[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_INVALID },
114	},
115	[GARP_APPLICANT_AO] = {
116	[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID },
117	[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QO },
118	[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VO },
119	[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VO },
120	[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VO },
121	[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VO },
122	[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_AP },
123	[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_INVALID },
124	},
125	[GARP_APPLICANT_QO] = {
126	[GARP_EVENT_TRANSMIT_PDU] = { .state = GARP_APPLICANT_INVALID },
127	[GARP_EVENT_R_JOIN_IN] = { .state = GARP_APPLICANT_QO },
128	[GARP_EVENT_R_JOIN_EMPTY] = { .state = GARP_APPLICANT_VO },
129	[GARP_EVENT_R_EMPTY] = { .state = GARP_APPLICANT_VO },
130	[GARP_EVENT_R_LEAVE_IN] = { .state = GARP_APPLICANT_VO },
131	[GARP_EVENT_R_LEAVE_EMPTY] = { .state = GARP_APPLICANT_VO },
132	[GARP_EVENT_REQ_JOIN] = { .state = GARP_APPLICANT_QP },
133	[GARP_EVENT_REQ_LEAVE] = { .state = GARP_APPLICANT_INVALID },
134	},
135	};
136
137	static int garp_attr_cmp(const struct garp_attr *attr,
138	const void *data, u8 len, u8 type)
139	{
140	if (attr->type != type)
141	return attr->type - type;
142	if (attr->dlen != len)
143	return attr->dlen - len;
144	return memcmp(attr->data, data, len);
145	}
146
147	static struct garp_attr garp_attr_lookup(const struct garp_applicant app,
148	const void *data, u8 len, u8 type)
149	{
150	struct rb_node *parent = app->gid.rb_node;
151	struct garp_attr *attr;
152	int d;
153
154	while (parent) {
155	attr = rb_entry(parent, struct garp_attr, node);
156	d = garp_attr_cmp(attr, data, len, type);
6f66cdc3	157	if (d > 0)
eca9ebac	158	parent = parent->rb_left;
6f66cdc3	159	else if (d < 0)
eca9ebac PM	160	parent = parent->rb_right;
	161	else
	162	return attr;
	163	}
	164	return NULL;
	165	}
	166
67378563 DW	167	static struct garp_attr garp_attr_create(struct garp_applicant app,
67378563 DW	168	const void *data, u8 len, u8 type)
eca9ebac PM	169	{
	170	struct rb_node parent = NULL, *p = &app->gid.rb_node;
	171	struct garp_attr *attr;
	172	int d;
	173
	174	while (*p) {
	175	parent = *p;
	176	attr = rb_entry(parent, struct garp_attr, node);
67378563	177	d = garp_attr_cmp(attr, data, len, type);
6f66cdc3	178	if (d > 0)
eca9ebac	179	p = &parent->rb_left;
6f66cdc3	180	else if (d < 0)
eca9ebac	181	p = &parent->rb_right;
67378563 DW	182	else {
	183	/* The attribute already exists; re-use it. */
	184	return attr;
	185	}
eca9ebac	186	}
eca9ebac PM	187	attr = kmalloc(sizeof(*attr) + len, GFP_ATOMIC);
	188	if (!attr)
	189	return attr;
	190	attr->state = GARP_APPLICANT_VO;
	191	attr->type = type;
	192	attr->dlen = len;
	193	memcpy(attr->data, data, len);
67378563 DW	194
	195	rb_link_node(&attr->node, parent, p);
	196	rb_insert_color(&attr->node, &app->gid);
eca9ebac PM	197	return attr;
	198	}
	199
	200	static void garp_attr_destroy(struct garp_applicant app, struct garp_attr attr)
	201	{
	202	rb_erase(&attr->node, &app->gid);
	203	kfree(attr);
	204	}
	205
	206	static int garp_pdu_init(struct garp_applicant *app)
	207	{
	208	struct sk_buff *skb;
	209	struct garp_pdu_hdr *gp;
	210
	211	#define LLC_RESERVE sizeof(struct llc_pdu_un)
	212	skb = alloc_skb(app->dev->mtu + LL_RESERVED_SPACE(app->dev),
	213	GFP_ATOMIC);
	214	if (!skb)
	215	return -ENOMEM;
	216
	217	skb->dev = app->dev;
	218	skb->protocol = htons(ETH_P_802_2);
	219	skb_reserve(skb, LL_RESERVED_SPACE(app->dev) + LLC_RESERVE);
	220
4df864c1	221	gp = __skb_put(skb, sizeof(*gp));
eca9ebac PM	222	put_unaligned(htons(GARP_PROTOCOL_ID), &gp->protocol);
	223
	224	app->pdu = skb;
	225	return 0;
	226	}
	227
	228	static int garp_pdu_append_end_mark(struct garp_applicant *app)
	229	{
	230	if (skb_tailroom(app->pdu) < sizeof(u8))
	231	return -1;
de77b966	232	__skb_put_u8(app->pdu, GARP_END_MARK);
eca9ebac PM	233	return 0;
	234	}
	235
	236	static void garp_pdu_queue(struct garp_applicant *app)
	237	{
	238	if (!app->pdu)
	239	return;
	240
	241	garp_pdu_append_end_mark(app);
	242	garp_pdu_append_end_mark(app);
	243
	244	llc_pdu_header_init(app->pdu, LLC_PDU_TYPE_U, LLC_SAP_BSPAN,
	245	LLC_SAP_BSPAN, LLC_PDU_CMD);
	246	llc_pdu_init_as_ui_cmd(app->pdu);
	247	llc_mac_hdr_init(app->pdu, app->dev->dev_addr,
	248	app->app->proto.group_address);
	249
	250	skb_queue_tail(&app->queue, app->pdu);
	251	app->pdu = NULL;
	252	}
	253
	254	static void garp_queue_xmit(struct garp_applicant *app)
	255	{
	256	struct sk_buff *skb;
	257
	258	while ((skb = skb_dequeue(&app->queue)))
	259	dev_queue_xmit(skb);
	260	}
	261
	262	static int garp_pdu_append_msg(struct garp_applicant *app, u8 attrtype)
	263	{
	264	struct garp_msg_hdr *gm;
	265
	266	if (skb_tailroom(app->pdu) < sizeof(*gm))
	267	return -1;
4df864c1	268	gm = __skb_put(app->pdu, sizeof(*gm));
eca9ebac PM	269	gm->attrtype = attrtype;
	270	garp_cb(app->pdu)->cur_type = attrtype;
	271	return 0;
	272	}
	273
	274	static int garp_pdu_append_attr(struct garp_applicant *app,
	275	const struct garp_attr *attr,
	276	enum garp_attr_event event)
	277	{
	278	struct garp_attr_hdr *ga;
	279	unsigned int len;
	280	int err;
	281	again:
	282	if (!app->pdu) {
	283	err = garp_pdu_init(app);
	284	if (err < 0)
	285	return err;
	286	}
	287
	288	if (garp_cb(app->pdu)->cur_type != attr->type) {
	289	if (garp_cb(app->pdu)->cur_type &&
	290	garp_pdu_append_end_mark(app) < 0)
	291	goto queue;
	292	if (garp_pdu_append_msg(app, attr->type) < 0)
	293	goto queue;
	294	}
	295
	296	len = sizeof(*ga) + attr->dlen;
	297	if (skb_tailroom(app->pdu) < len)
	298	goto queue;
4df864c1	299	ga = __skb_put(app->pdu, len);
eca9ebac PM	300	ga->len = len;
	301	ga->event = event;
	302	memcpy(ga->data, attr->data, attr->dlen);
	303	return 0;
	304
	305	queue:
	306	garp_pdu_queue(app);
	307	goto again;
	308	}
	309
	310	static void garp_attr_event(struct garp_applicant *app,
	311	struct garp_attr *attr, enum garp_event event)
	312	{
	313	enum garp_applicant_state state;
	314
	315	state = garp_applicant_state_table[attr->state][event].state;
	316	if (state == GARP_APPLICANT_INVALID)
	317	return;
	318
	319	switch (garp_applicant_state_table[attr->state][event].action) {
	320	case GARP_ACTION_NONE:
	321	break;
	322	case GARP_ACTION_S_JOIN_IN:
51ce7ec9 PM	323	/* When appending the attribute fails, don't update state in
	324	* order to retry on next TRANSMIT_PDU event. */
	325	if (garp_pdu_append_attr(app, attr, GARP_JOIN_IN) < 0)
	326	return;
eca9ebac PM	327	break;
	328	case GARP_ACTION_S_LEAVE_EMPTY:
	329	garp_pdu_append_attr(app, attr, GARP_LEAVE_EMPTY);
	330	/* As a pure applicant, sending a leave message implies that
	331	* the attribute was unregistered and can be destroyed. */
	332	garp_attr_destroy(app, attr);
	333	return;
	334	default:
	335	WARN_ON(1);
	336	}
	337
	338	attr->state = state;
	339	}
	340
	341	int garp_request_join(const struct net_device *dev,
	342	const struct garp_application *appl,
	343	const void *data, u8 len, u8 type)
	344	{
3cc77ec7 ED	345	struct garp_port *port = rtnl_dereference(dev->garp_port);
3cc77ec7 ED	346	struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
eca9ebac PM	347	struct garp_attr *attr;
	348
	349	spin_lock_bh(&app->lock);
	350	attr = garp_attr_create(app, data, len, type);
	351	if (!attr) {
	352	spin_unlock_bh(&app->lock);
	353	return -ENOMEM;
	354	}
	355	garp_attr_event(app, attr, GARP_EVENT_REQ_JOIN);
	356	spin_unlock_bh(&app->lock);
	357	return 0;
	358	}
	359	EXPORT_SYMBOL_GPL(garp_request_join);
	360
	361	void garp_request_leave(const struct net_device *dev,
	362	const struct garp_application *appl,
	363	const void *data, u8 len, u8 type)
	364	{
3cc77ec7 ED	365	struct garp_port *port = rtnl_dereference(dev->garp_port);
3cc77ec7 ED	366	struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
eca9ebac PM	367	struct garp_attr *attr;
	368
	369	spin_lock_bh(&app->lock);
	370	attr = garp_attr_lookup(app, data, len, type);
	371	if (!attr) {
	372	spin_unlock_bh(&app->lock);
	373	return;
	374	}
	375	garp_attr_event(app, attr, GARP_EVENT_REQ_LEAVE);
	376	spin_unlock_bh(&app->lock);
	377	}
	378	EXPORT_SYMBOL_GPL(garp_request_leave);
	379
	380	static void garp_gid_event(struct garp_applicant *app, enum garp_event event)
	381	{
	382	struct rb_node node, next;
	383	struct garp_attr *attr;
	384
	385	for (node = rb_first(&app->gid);
	386	next = node ? rb_next(node) : NULL, node != NULL;
	387	node = next) {
	388	attr = rb_entry(node, struct garp_attr, node);
	389	garp_attr_event(app, attr, event);
	390	}
	391	}
	392
	393	static void garp_join_timer_arm(struct garp_applicant *app)
	394	{
	395	unsigned long delay;
	396
63862b5b	397	delay = (u64)msecs_to_jiffies(garp_join_time) * prandom_u32() >> 32;
eca9ebac PM	398	mod_timer(&app->join_timer, jiffies + delay);
	399	}
	400
e99e88a9	401	static void garp_join_timer(struct timer_list *t)
eca9ebac	402	{
e99e88a9	403	struct garp_applicant *app = from_timer(app, t, join_timer);
eca9ebac PM	404
	405	spin_lock(&app->lock);
	406	garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
	407	garp_pdu_queue(app);
	408	spin_unlock(&app->lock);
	409
	410	garp_queue_xmit(app);
	411	garp_join_timer_arm(app);
	412	}
	413
	414	static int garp_pdu_parse_end_mark(struct sk_buff *skb)
	415	{
	416	if (!pskb_may_pull(skb, sizeof(u8)))
	417	return -1;
	418	if (*skb->data == GARP_END_MARK) {
	419	skb_pull(skb, sizeof(u8));
	420	return -1;
	421	}
	422	return 0;
	423	}
	424
	425	static int garp_pdu_parse_attr(struct garp_applicant app, struct sk_buff skb,
	426	u8 attrtype)
	427	{
	428	const struct garp_attr_hdr *ga;
	429	struct garp_attr *attr;
	430	enum garp_event event;
	431	unsigned int dlen;
	432
	433	if (!pskb_may_pull(skb, sizeof(*ga)))
	434	return -1;
	435	ga = (struct garp_attr_hdr *)skb->data;
	436	if (ga->len < sizeof(*ga))
	437	return -1;
	438
	439	if (!pskb_may_pull(skb, ga->len))
	440	return -1;
	441	skb_pull(skb, ga->len);
	442	dlen = sizeof(*ga) - ga->len;
	443
	444	if (attrtype > app->app->maxattr)
	445	return 0;
	446
	447	switch (ga->event) {
	448	case GARP_LEAVE_ALL:
	449	if (dlen != 0)
	450	return -1;
	451	garp_gid_event(app, GARP_EVENT_R_LEAVE_EMPTY);
	452	return 0;
	453	case GARP_JOIN_EMPTY:
	454	event = GARP_EVENT_R_JOIN_EMPTY;
	455	break;
	456	case GARP_JOIN_IN:
	457	event = GARP_EVENT_R_JOIN_IN;
	458	break;
	459	case GARP_LEAVE_EMPTY:
	460	event = GARP_EVENT_R_LEAVE_EMPTY;
	461	break;
	462	case GARP_EMPTY:
	463	event = GARP_EVENT_R_EMPTY;
	464	break;
	465	default:
	466	return 0;
	467	}
468
469	if (dlen == 0)
470	return -1;
471	attr = garp_attr_lookup(app, ga->data, dlen, attrtype);
472	if (attr == NULL)
473	return 0;
474	garp_attr_event(app, attr, event);
475	return 0;
476	}
477
478	static int garp_pdu_parse_msg(struct garp_applicant app, struct sk_buff skb)
479	{
480	const struct garp_msg_hdr *gm;
481
482	if (!pskb_may_pull(skb, sizeof(*gm)))
483	return -1;
484	gm = (struct garp_msg_hdr *)skb->data;
485	if (gm->attrtype == 0)
486	return -1;
487	skb_pull(skb, sizeof(*gm));
488
489	while (skb->len > 0) {
490	if (garp_pdu_parse_attr(app, skb, gm->attrtype) < 0)
491	return -1;
492	if (garp_pdu_parse_end_mark(skb) < 0)
493	break;
494	}
495	return 0;
496	}
497
498	static void garp_pdu_rcv(const struct stp_proto proto, struct sk_buff skb,
499	struct net_device *dev)
500	{
501	struct garp_application *appl = proto->data;
502	struct garp_port *port;
503	struct garp_applicant *app;
504	const struct garp_pdu_hdr *gp;
505
506	port = rcu_dereference(dev->garp_port);
507	if (!port)
508	goto err;
509	app = rcu_dereference(port->applicants[appl->type]);
510	if (!app)
511	goto err;
512
513	if (!pskb_may_pull(skb, sizeof(*gp)))
514	goto err;
515	gp = (struct garp_pdu_hdr *)skb->data;
516	if (get_unaligned(&gp->protocol) != htons(GARP_PROTOCOL_ID))
517	goto err;
518	skb_pull(skb, sizeof(*gp));
519
520	spin_lock(&app->lock);
521	while (skb->len > 0) {
522	if (garp_pdu_parse_msg(app, skb) < 0)
523	break;
524	if (garp_pdu_parse_end_mark(skb) < 0)
525	break;
526	}
527	spin_unlock(&app->lock);
528	err:
529	kfree_skb(skb);
530	}
531
532	static int garp_init_port(struct net_device *dev)
533	{
534	struct garp_port *port;
535
536	port = kzalloc(sizeof(*port), GFP_KERNEL);
537	if (!port)
538	return -ENOMEM;
539	rcu_assign_pointer(dev->garp_port, port);
540	return 0;
541	}
542
543	static void garp_release_port(struct net_device *dev)
544	{
3cc77ec7	545	struct garp_port *port = rtnl_dereference(dev->garp_port);
eca9ebac PM	546	unsigned int i;
	547
	548	for (i = 0; i <= GARP_APPLICATION_MAX; i++) {
3cc77ec7	549	if (rtnl_dereference(port->applicants[i]))
eca9ebac PM	550	return;
eca9ebac PM	551	}
a9b3cd7f	552	RCU_INIT_POINTER(dev->garp_port, NULL);
0a384b22	553	kfree_rcu(port, rcu);
eca9ebac PM	554	}
	555
	556	int garp_init_applicant(struct net_device dev, struct garp_application appl)
	557	{
	558	struct garp_applicant *app;
	559	int err;
	560
	561	ASSERT_RTNL();
	562
3cc77ec7	563	if (!rtnl_dereference(dev->garp_port)) {
eca9ebac PM	564	err = garp_init_port(dev);
	565	if (err < 0)
	566	goto err1;
	567	}
	568
	569	err = -ENOMEM;
	570	app = kzalloc(sizeof(*app), GFP_KERNEL);
	571	if (!app)
	572	goto err2;
	573
22bedad3	574	err = dev_mc_add(dev, appl->proto.group_address);
eca9ebac PM	575	if (err < 0)
	576	goto err3;
	577
	578	app->dev = dev;
	579	app->app = appl;
	580	app->gid = RB_ROOT;
	581	spin_lock_init(&app->lock);
	582	skb_queue_head_init(&app->queue);
	583	rcu_assign_pointer(dev->garp_port->applicants[appl->type], app);
e99e88a9	584	timer_setup(&app->join_timer, garp_join_timer, 0);
eca9ebac PM	585	garp_join_timer_arm(app);
	586	return 0;
	587
	588	err3:
	589	kfree(app);
	590	err2:
	591	garp_release_port(dev);
	592	err1:
	593	return err;
	594	}
	595	EXPORT_SYMBOL_GPL(garp_init_applicant);
	596
	597	void garp_uninit_applicant(struct net_device dev, struct garp_application appl)
	598	{
3cc77ec7 ED	599	struct garp_port *port = rtnl_dereference(dev->garp_port);
3cc77ec7 ED	600	struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
eca9ebac PM	601
	602	ASSERT_RTNL();
	603
a9b3cd7f	604	RCU_INIT_POINTER(port->applicants[appl->type], NULL);
eca9ebac PM	605
	606	/* Delete timer and generate a final TRANSMIT_PDU event to flush out
	607	* all pending messages before the applicant is gone. */
	608	del_timer_sync(&app->join_timer);
cfbe800b CW	609
cfbe800b CW	610	spin_lock_bh(&app->lock);
eca9ebac PM	611	garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
eca9ebac PM	612	garp_pdu_queue(app);
cfbe800b CW	613	spin_unlock_bh(&app->lock);
cfbe800b CW	614
eca9ebac PM	615	garp_queue_xmit(app);
eca9ebac PM	616
22bedad3	617	dev_mc_del(dev, appl->proto.group_address);
0a384b22	618	kfree_rcu(app, rcu);
eca9ebac PM	619	garp_release_port(dev);
	620	}
	621	EXPORT_SYMBOL_GPL(garp_uninit_applicant);
	622
	623	int garp_register_application(struct garp_application *appl)
	624	{
	625	appl->proto.rcv = garp_pdu_rcv;
	626	appl->proto.data = appl;
	627	return stp_proto_register(&appl->proto);
	628	}
	629	EXPORT_SYMBOL_GPL(garp_register_application);
	630
	631	void garp_unregister_application(struct garp_application *appl)
	632	{
	633	stp_proto_unregister(&appl->proto);
	634	}
	635	EXPORT_SYMBOL_GPL(garp_unregister_application);