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

/*
 *	IEEE 802.1D Generic Attribute Registration Protocol (GARP)
 *
 *	Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
 *
 *	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 void garp_attr_insert(struct garp_applicant *app, struct garp_attr *new)
{
	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, new->data, new->dlen, new->type);
		if (d < 0)
			p = &parent->rb_left;
		else if (d > 0)
			p = &parent->rb_right;
	}
	rb_link_node(&new->node, parent, p);
	rb_insert_color(&new->node, &app->gid);
}

static struct garp_attr *garp_attr_create(struct garp_applicant *app,
					  const void *data, u8 len, u8 type)
{
	struct garp_attr *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);
	garp_attr_insert(app, attr);
	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 <kaber@trash.net>
	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);
160	if (d < 0)
161	parent = parent->rb_left;
162	else if (d > 0)
163	parent = parent->rb_right;
164	else
165	return attr;
166	}
167	return NULL;
168	}
169
170	static void garp_attr_insert(struct garp_applicant app, struct garp_attr new)
171	{
172	struct rb_node parent = NULL, *p = &app->gid.rb_node;
173	struct garp_attr *attr;
174	int d;
175
176	while (*p) {
177	parent = *p;
178	attr = rb_entry(parent, struct garp_attr, node);
179	d = garp_attr_cmp(attr, new->data, new->dlen, new->type);
180	if (d < 0)
181	p = &parent->rb_left;
182	else if (d > 0)
183	p = &parent->rb_right;
184	}
185	rb_link_node(&new->node, parent, p);
186	rb_insert_color(&new->node, &app->gid);
187	}
188
189	static struct garp_attr garp_attr_create(struct garp_applicant app,
190	const void *data, u8 len, u8 type)
191	{
192	struct garp_attr *attr;
193
194	attr = kmalloc(sizeof(*attr) + len, GFP_ATOMIC);
195	if (!attr)
196	return attr;
197	attr->state = GARP_APPLICANT_VO;
198	attr->type = type;
199	attr->dlen = len;
200	memcpy(attr->data, data, len);
201	garp_attr_insert(app, attr);
202	return attr;
203	}
204
205	static void garp_attr_destroy(struct garp_applicant app, struct garp_attr attr)
206	{
207	rb_erase(&attr->node, &app->gid);
208	kfree(attr);
209	}
210
211	static int garp_pdu_init(struct garp_applicant *app)
212	{
213	struct sk_buff *skb;
214	struct garp_pdu_hdr *gp;
215
216	#define LLC_RESERVE sizeof(struct llc_pdu_un)
217	skb = alloc_skb(app->dev->mtu + LL_RESERVED_SPACE(app->dev),
218	GFP_ATOMIC);
219	if (!skb)
220	return -ENOMEM;
221
222	skb->dev = app->dev;
223	skb->protocol = htons(ETH_P_802_2);
224	skb_reserve(skb, LL_RESERVED_SPACE(app->dev) + LLC_RESERVE);
225
226	gp = (struct garp_pdu_hdr )__skb_put(skb, sizeof(gp));
227	put_unaligned(htons(GARP_PROTOCOL_ID), &gp->protocol);
228
229	app->pdu = skb;
230	return 0;
231	}
232
233	static int garp_pdu_append_end_mark(struct garp_applicant *app)
234	{
235	if (skb_tailroom(app->pdu) < sizeof(u8))
236	return -1;
237	(u8 )__skb_put(app->pdu, sizeof(u8)) = GARP_END_MARK;
238	return 0;
239	}
240
241	static void garp_pdu_queue(struct garp_applicant *app)
242	{
243	if (!app->pdu)
244	return;
245
246	garp_pdu_append_end_mark(app);
247	garp_pdu_append_end_mark(app);
248
249	llc_pdu_header_init(app->pdu, LLC_PDU_TYPE_U, LLC_SAP_BSPAN,
250	LLC_SAP_BSPAN, LLC_PDU_CMD);
251	llc_pdu_init_as_ui_cmd(app->pdu);
252	llc_mac_hdr_init(app->pdu, app->dev->dev_addr,
253	app->app->proto.group_address);
254
255	skb_queue_tail(&app->queue, app->pdu);
256	app->pdu = NULL;
257	}
258
259	static void garp_queue_xmit(struct garp_applicant *app)
260	{
261	struct sk_buff *skb;
262
263	while ((skb = skb_dequeue(&app->queue)))
264	dev_queue_xmit(skb);
265	}
266
267	static int garp_pdu_append_msg(struct garp_applicant *app, u8 attrtype)
268	{
269	struct garp_msg_hdr *gm;
270
271	if (skb_tailroom(app->pdu) < sizeof(*gm))
272	return -1;
273	gm = (struct garp_msg_hdr )__skb_put(app->pdu, sizeof(gm));
274	gm->attrtype = attrtype;
275	garp_cb(app->pdu)->cur_type = attrtype;
276	return 0;
277	}
278
279	static int garp_pdu_append_attr(struct garp_applicant *app,
280	const struct garp_attr *attr,
281	enum garp_attr_event event)
282	{
283	struct garp_attr_hdr *ga;
284	unsigned int len;
285	int err;
286	again:
287	if (!app->pdu) {
288	err = garp_pdu_init(app);
289	if (err < 0)
290	return err;
291	}
292
293	if (garp_cb(app->pdu)->cur_type != attr->type) {
294	if (garp_cb(app->pdu)->cur_type &&
295	garp_pdu_append_end_mark(app) < 0)
296	goto queue;
297	if (garp_pdu_append_msg(app, attr->type) < 0)
298	goto queue;
299	}
300
301	len = sizeof(*ga) + attr->dlen;
302	if (skb_tailroom(app->pdu) < len)
303	goto queue;
304	ga = (struct garp_attr_hdr *)__skb_put(app->pdu, len);
305	ga->len = len;
306	ga->event = event;
307	memcpy(ga->data, attr->data, attr->dlen);
308	return 0;
309
310	queue:
311	garp_pdu_queue(app);
312	goto again;
313	}
314
315	static void garp_attr_event(struct garp_applicant *app,
316	struct garp_attr *attr, enum garp_event event)
317	{
318	enum garp_applicant_state state;
319
320	state = garp_applicant_state_table[attr->state][event].state;
321	if (state == GARP_APPLICANT_INVALID)
322	return;
323
324	switch (garp_applicant_state_table[attr->state][event].action) {
325	case GARP_ACTION_NONE:
326	break;
327	case GARP_ACTION_S_JOIN_IN:
51ce7ec9 PM	328	/* When appending the attribute fails, don't update state in
	329	* order to retry on next TRANSMIT_PDU event. */
	330	if (garp_pdu_append_attr(app, attr, GARP_JOIN_IN) < 0)
	331	return;
eca9ebac PM	332	break;
	333	case GARP_ACTION_S_LEAVE_EMPTY:
	334	garp_pdu_append_attr(app, attr, GARP_LEAVE_EMPTY);
	335	/* As a pure applicant, sending a leave message implies that
	336	* the attribute was unregistered and can be destroyed. */
	337	garp_attr_destroy(app, attr);
	338	return;
	339	default:
	340	WARN_ON(1);
	341	}
	342
	343	attr->state = state;
	344	}
	345
	346	int garp_request_join(const struct net_device *dev,
	347	const struct garp_application *appl,
	348	const void *data, u8 len, u8 type)
	349	{
3cc77ec7 ED	350	struct garp_port *port = rtnl_dereference(dev->garp_port);
3cc77ec7 ED	351	struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
eca9ebac PM	352	struct garp_attr *attr;
	353
	354	spin_lock_bh(&app->lock);
	355	attr = garp_attr_create(app, data, len, type);
	356	if (!attr) {
	357	spin_unlock_bh(&app->lock);
	358	return -ENOMEM;
	359	}
	360	garp_attr_event(app, attr, GARP_EVENT_REQ_JOIN);
	361	spin_unlock_bh(&app->lock);
	362	return 0;
	363	}
	364	EXPORT_SYMBOL_GPL(garp_request_join);
	365
	366	void garp_request_leave(const struct net_device *dev,
	367	const struct garp_application *appl,
	368	const void *data, u8 len, u8 type)
	369	{
3cc77ec7 ED	370	struct garp_port *port = rtnl_dereference(dev->garp_port);
3cc77ec7 ED	371	struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
eca9ebac PM	372	struct garp_attr *attr;
	373
	374	spin_lock_bh(&app->lock);
	375	attr = garp_attr_lookup(app, data, len, type);
	376	if (!attr) {
	377	spin_unlock_bh(&app->lock);
	378	return;
	379	}
	380	garp_attr_event(app, attr, GARP_EVENT_REQ_LEAVE);
	381	spin_unlock_bh(&app->lock);
	382	}
	383	EXPORT_SYMBOL_GPL(garp_request_leave);
	384
	385	static void garp_gid_event(struct garp_applicant *app, enum garp_event event)
	386	{
	387	struct rb_node node, next;
	388	struct garp_attr *attr;
	389
	390	for (node = rb_first(&app->gid);
	391	next = node ? rb_next(node) : NULL, node != NULL;
	392	node = next) {
	393	attr = rb_entry(node, struct garp_attr, node);
	394	garp_attr_event(app, attr, event);
	395	}
	396	}
	397
	398	static void garp_join_timer_arm(struct garp_applicant *app)
	399	{
	400	unsigned long delay;
	401
	402	delay = (u64)msecs_to_jiffies(garp_join_time) * net_random() >> 32;
	403	mod_timer(&app->join_timer, jiffies + delay);
	404	}
	405
	406	static void garp_join_timer(unsigned long data)
	407	{
	408	struct garp_applicant app = (struct garp_applicant )data;
	409
	410	spin_lock(&app->lock);
	411	garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
	412	garp_pdu_queue(app);
	413	spin_unlock(&app->lock);
	414
	415	garp_queue_xmit(app);
	416	garp_join_timer_arm(app);
	417	}
	418
	419	static int garp_pdu_parse_end_mark(struct sk_buff *skb)
	420	{
	421	if (!pskb_may_pull(skb, sizeof(u8)))
	422	return -1;
	423	if (*skb->data == GARP_END_MARK) {
	424	skb_pull(skb, sizeof(u8));
	425	return -1;
	426	}
	427	return 0;
	428	}
	429
	430	static int garp_pdu_parse_attr(struct garp_applicant app, struct sk_buff skb,
	431	u8 attrtype)
	432	{
	433	const struct garp_attr_hdr *ga;
	434	struct garp_attr *attr;
	435	enum garp_event event;
436	unsigned int dlen;
437
438	if (!pskb_may_pull(skb, sizeof(*ga)))
439	return -1;
440	ga = (struct garp_attr_hdr *)skb->data;
441	if (ga->len < sizeof(*ga))
442	return -1;
443
444	if (!pskb_may_pull(skb, ga->len))
445	return -1;
446	skb_pull(skb, ga->len);
447	dlen = sizeof(*ga) - ga->len;
448
449	if (attrtype > app->app->maxattr)
450	return 0;
451
452	switch (ga->event) {
453	case GARP_LEAVE_ALL:
454	if (dlen != 0)
455	return -1;
456	garp_gid_event(app, GARP_EVENT_R_LEAVE_EMPTY);
457	return 0;
458	case GARP_JOIN_EMPTY:
459	event = GARP_EVENT_R_JOIN_EMPTY;
460	break;
461	case GARP_JOIN_IN:
462	event = GARP_EVENT_R_JOIN_IN;
463	break;
464	case GARP_LEAVE_EMPTY:
465	event = GARP_EVENT_R_LEAVE_EMPTY;
466	break;
467	case GARP_EMPTY:
468	event = GARP_EVENT_R_EMPTY;
469	break;
470	default:
471	return 0;
472	}
473
474	if (dlen == 0)
475	return -1;
476	attr = garp_attr_lookup(app, ga->data, dlen, attrtype);
477	if (attr == NULL)
478	return 0;
479	garp_attr_event(app, attr, event);
480	return 0;
481	}
482
483	static int garp_pdu_parse_msg(struct garp_applicant app, struct sk_buff skb)
484	{
485	const struct garp_msg_hdr *gm;
486
487	if (!pskb_may_pull(skb, sizeof(*gm)))
488	return -1;
489	gm = (struct garp_msg_hdr *)skb->data;
490	if (gm->attrtype == 0)
491	return -1;
492	skb_pull(skb, sizeof(*gm));
493
494	while (skb->len > 0) {
495	if (garp_pdu_parse_attr(app, skb, gm->attrtype) < 0)
496	return -1;
497	if (garp_pdu_parse_end_mark(skb) < 0)
498	break;
499	}
500	return 0;
501	}
502
503	static void garp_pdu_rcv(const struct stp_proto proto, struct sk_buff skb,
504	struct net_device *dev)
505	{
506	struct garp_application *appl = proto->data;
507	struct garp_port *port;
508	struct garp_applicant *app;
509	const struct garp_pdu_hdr *gp;
510
511	port = rcu_dereference(dev->garp_port);
512	if (!port)
513	goto err;
514	app = rcu_dereference(port->applicants[appl->type]);
515	if (!app)
516	goto err;
517
518	if (!pskb_may_pull(skb, sizeof(*gp)))
519	goto err;
520	gp = (struct garp_pdu_hdr *)skb->data;
521	if (get_unaligned(&gp->protocol) != htons(GARP_PROTOCOL_ID))
522	goto err;
523	skb_pull(skb, sizeof(*gp));
524
525	spin_lock(&app->lock);
526	while (skb->len > 0) {
527	if (garp_pdu_parse_msg(app, skb) < 0)
528	break;
529	if (garp_pdu_parse_end_mark(skb) < 0)
530	break;
531	}
532	spin_unlock(&app->lock);
533	err:
534	kfree_skb(skb);
535	}
536
537	static int garp_init_port(struct net_device *dev)
538	{
539	struct garp_port *port;
540
541	port = kzalloc(sizeof(*port), GFP_KERNEL);
542	if (!port)
543	return -ENOMEM;
544	rcu_assign_pointer(dev->garp_port, port);
545	return 0;
546	}
547
548	static void garp_release_port(struct net_device *dev)
549	{
3cc77ec7	550	struct garp_port *port = rtnl_dereference(dev->garp_port);
eca9ebac PM	551	unsigned int i;
	552
	553	for (i = 0; i <= GARP_APPLICATION_MAX; i++) {
3cc77ec7	554	if (rtnl_dereference(port->applicants[i]))
eca9ebac PM	555	return;
eca9ebac PM	556	}
a9b3cd7f	557	RCU_INIT_POINTER(dev->garp_port, NULL);
0a384b22	558	kfree_rcu(port, rcu);
eca9ebac PM	559	}
	560
	561	int garp_init_applicant(struct net_device dev, struct garp_application appl)
	562	{
	563	struct garp_applicant *app;
	564	int err;
	565
	566	ASSERT_RTNL();
	567
3cc77ec7	568	if (!rtnl_dereference(dev->garp_port)) {
eca9ebac PM	569	err = garp_init_port(dev);
	570	if (err < 0)
	571	goto err1;
	572	}
	573
	574	err = -ENOMEM;
	575	app = kzalloc(sizeof(*app), GFP_KERNEL);
	576	if (!app)
	577	goto err2;
	578
22bedad3	579	err = dev_mc_add(dev, appl->proto.group_address);
eca9ebac PM	580	if (err < 0)
	581	goto err3;
	582
	583	app->dev = dev;
	584	app->app = appl;
	585	app->gid = RB_ROOT;
	586	spin_lock_init(&app->lock);
	587	skb_queue_head_init(&app->queue);
	588	rcu_assign_pointer(dev->garp_port->applicants[appl->type], app);
	589	setup_timer(&app->join_timer, garp_join_timer, (unsigned long)app);
	590	garp_join_timer_arm(app);
	591	return 0;
	592
	593	err3:
	594	kfree(app);
	595	err2:
	596	garp_release_port(dev);
	597	err1:
	598	return err;
	599	}
	600	EXPORT_SYMBOL_GPL(garp_init_applicant);
	601
	602	void garp_uninit_applicant(struct net_device dev, struct garp_application appl)
	603	{
3cc77ec7 ED	604	struct garp_port *port = rtnl_dereference(dev->garp_port);
3cc77ec7 ED	605	struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
eca9ebac PM	606
	607	ASSERT_RTNL();
	608
a9b3cd7f	609	RCU_INIT_POINTER(port->applicants[appl->type], NULL);
eca9ebac PM	610
	611	/* Delete timer and generate a final TRANSMIT_PDU event to flush out
	612	* all pending messages before the applicant is gone. */
	613	del_timer_sync(&app->join_timer);
	614	garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
	615	garp_pdu_queue(app);
	616	garp_queue_xmit(app);
	617
22bedad3	618	dev_mc_del(dev, appl->proto.group_address);
0a384b22	619	kfree_rcu(app, rcu);
eca9ebac PM	620	garp_release_port(dev);
	621	}
	622	EXPORT_SYMBOL_GPL(garp_uninit_applicant);
	623
	624	int garp_register_application(struct garp_application *appl)
	625	{
	626	appl->proto.rcv = garp_pdu_rcv;
	627	appl->proto.data = appl;
	628	return stp_proto_register(&appl->proto);
	629	}
	630	EXPORT_SYMBOL_GPL(garp_register_application);
	631
	632	void garp_unregister_application(struct garp_application *appl)
	633	{
	634	stp_proto_unregister(&appl->proto);
	635	}
	636	EXPORT_SYMBOL_GPL(garp_unregister_application);