[linux.git] / net / 802 / garp.c

/*
 *	IEEE 802.1D Generic Attribute Registration Protocol (GARP)
 *
 *	Copyright (c) 2008 Patrick McHardy <[email protected]>
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	version 2 as published by the Free Software Foundation.
 */
#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 = (struct garp_pdu_hdr *)__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;
	*(u8 *)__skb_put(app->pdu, sizeof(u8)) = 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 = (struct garp_msg_hdr *)__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 = (struct garp_attr_hdr *)__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) * net_random() >> 32;
	mod_timer(&app->join_timer, jiffies + delay);
}

static void garp_join_timer(unsigned long data)
{
	struct garp_applicant *app = (struct garp_applicant *)data;

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