[linux-2.6-block.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 void garp_attr_destroy_all(struct garp_applicant *app)
{
	struct rb_node *node, *next;
	struct garp_attr *attr;

	for (node = rb_first(&app->gid);
	     next = node ? rb_next(node) : NULL, node != NULL;
	     node = next) {
		attr = rb_entry(node, struct garp_attr, node);
		garp_attr_destroy(app, attr);
	}
}

static int garp_pdu_init(struct garp_applicant *app)
{
	struct sk_buff *skb;
	struct garp_pdu_hdr *gp;

#define LLC_RESERVE	sizeof(struct llc_pdu_un)
	skb = alloc_skb(app->dev->mtu + LL_RESERVED_SPACE(app->dev),
			GFP_ATOMIC);
	if (!skb)
		return -ENOMEM;

	skb->dev = app->dev;
	skb->protocol = htons(ETH_P_802_2);
	skb_reserve(skb, LL_RESERVED_SPACE(app->dev) + LLC_RESERVE);

	gp = __skb_put(skb, sizeof(*gp));
	put_unaligned(htons(GARP_PROTOCOL_ID), &gp->protocol);

	app->pdu = skb;
	return 0;
}

static int garp_pdu_append_end_mark(struct garp_applicant *app)
{
	if (skb_tailroom(app->pdu) < sizeof(u8))
		return -1;
	__skb_put_u8(app->pdu, GARP_END_MARK);
	return 0;
}

static void garp_pdu_queue(struct garp_applicant *app)
{
	if (!app->pdu)
		return;

	garp_pdu_append_end_mark(app);
	garp_pdu_append_end_mark(app);

	llc_pdu_header_init(app->pdu, LLC_PDU_TYPE_U, LLC_SAP_BSPAN,
			    LLC_SAP_BSPAN, LLC_PDU_CMD);
	llc_pdu_init_as_ui_cmd(app->pdu);
	llc_mac_hdr_init(app->pdu, app->dev->dev_addr,
			 app->app->proto.group_address);

	skb_queue_tail(&app->queue, app->pdu);
	app->pdu = NULL;
}

static void garp_queue_xmit(struct garp_applicant *app)
{
	struct sk_buff *skb;

	while ((skb = skb_dequeue(&app->queue)))
		dev_queue_xmit(skb);
}

static int garp_pdu_append_msg(struct garp_applicant *app, u8 attrtype)
{
	struct garp_msg_hdr *gm;

	if (skb_tailroom(app->pdu) < sizeof(*gm))
		return -1;
	gm = __skb_put(app->pdu, sizeof(*gm));
	gm->attrtype = attrtype;
	garp_cb(app->pdu)->cur_type = attrtype;
	return 0;
}

static int garp_pdu_append_attr(struct garp_applicant *app,
				const struct garp_attr *attr,
				enum garp_attr_event event)
{
	struct garp_attr_hdr *ga;
	unsigned int len;
	int err;
again:
	if (!app->pdu) {
		err = garp_pdu_init(app);
		if (err < 0)
			return err;
	}

	if (garp_cb(app->pdu)->cur_type != attr->type) {
		if (garp_cb(app->pdu)->cur_type &&
		    garp_pdu_append_end_mark(app) < 0)
			goto queue;
		if (garp_pdu_append_msg(app, attr->type) < 0)
			goto queue;
	}

	len = sizeof(*ga) + attr->dlen;
	if (skb_tailroom(app->pdu) < len)
		goto queue;
	ga = __skb_put(app->pdu, len);
	ga->len   = len;
	ga->event = event;
	memcpy(ga->data, attr->data, attr->dlen);
	return 0;

queue:
	garp_pdu_queue(app);
	goto again;
}

static void garp_attr_event(struct garp_applicant *app,
			    struct garp_attr *attr, enum garp_event event)
{
	enum garp_applicant_state state;

	state = garp_applicant_state_table[attr->state][event].state;
	if (state == GARP_APPLICANT_INVALID)
		return;

	switch (garp_applicant_state_table[attr->state][event].action) {
	case GARP_ACTION_NONE:
		break;
	case GARP_ACTION_S_JOIN_IN:
		/* When appending the attribute fails, don't update state in
		 * order to retry on next TRANSMIT_PDU event. */
		if (garp_pdu_append_attr(app, attr, GARP_JOIN_IN) < 0)
			return;
		break;
	case GARP_ACTION_S_LEAVE_EMPTY:
		garp_pdu_append_attr(app, attr, GARP_LEAVE_EMPTY);
		/* As a pure applicant, sending a leave message implies that
		 * the attribute was unregistered and can be destroyed. */
		garp_attr_destroy(app, attr);
		return;
	default:
		WARN_ON(1);
	}

	attr->state = state;
}

int garp_request_join(const struct net_device *dev,
		      const struct garp_application *appl,
		      const void *data, u8 len, u8 type)
{
	struct garp_port *port = rtnl_dereference(dev->garp_port);
	struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
	struct garp_attr *attr;

	spin_lock_bh(&app->lock);
	attr = garp_attr_create(app, data, len, type);
	if (!attr) {
		spin_unlock_bh(&app->lock);
		return -ENOMEM;
	}
	garp_attr_event(app, attr, GARP_EVENT_REQ_JOIN);
	spin_unlock_bh(&app->lock);
	return 0;
}
EXPORT_SYMBOL_GPL(garp_request_join);

void garp_request_leave(const struct net_device *dev,
			const struct garp_application *appl,
			const void *data, u8 len, u8 type)
{
	struct garp_port *port = rtnl_dereference(dev->garp_port);
	struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
	struct garp_attr *attr;

	spin_lock_bh(&app->lock);
	attr = garp_attr_lookup(app, data, len, type);
	if (!attr) {
		spin_unlock_bh(&app->lock);
		return;
	}
	garp_attr_event(app, attr, GARP_EVENT_REQ_LEAVE);
	spin_unlock_bh(&app->lock);
}
EXPORT_SYMBOL_GPL(garp_request_leave);

static void garp_gid_event(struct garp_applicant *app, enum garp_event event)
{
	struct rb_node *node, *next;
	struct garp_attr *attr;

	for (node = rb_first(&app->gid);
	     next = node ? rb_next(node) : NULL, node != NULL;
	     node = next) {
		attr = rb_entry(node, struct garp_attr, node);
		garp_attr_event(app, attr, event);
	}
}

static void garp_join_timer_arm(struct garp_applicant *app)
{
	unsigned long delay;

	delay = get_random_u32_below(msecs_to_jiffies(garp_join_time));
	mod_timer(&app->join_timer, jiffies + delay);
}

static void garp_join_timer(struct timer_list *t)
{
	struct garp_applicant *app = from_timer(app, t, join_timer);

	spin_lock(&app->lock);
	garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
	garp_pdu_queue(app);
	spin_unlock(&app->lock);

	garp_queue_xmit(app);
	garp_join_timer_arm(app);
}

static int garp_pdu_parse_end_mark(struct sk_buff *skb)
{
	if (!pskb_may_pull(skb, sizeof(u8)))
		return -1;
	if (*skb->data == GARP_END_MARK) {
		skb_pull(skb, sizeof(u8));
		return -1;
	}
	return 0;
}

static int garp_pdu_parse_attr(struct garp_applicant *app, struct sk_buff *skb,
			       u8 attrtype)
{
	const struct garp_attr_hdr *ga;
	struct garp_attr *attr;
	enum garp_event event;
	unsigned int dlen;

	if (!pskb_may_pull(skb, sizeof(*ga)))
		return -1;
	ga = (struct garp_attr_hdr *)skb->data;
	if (ga->len < sizeof(*ga))
		return -1;

	if (!pskb_may_pull(skb, ga->len))
		return -1;
	skb_pull(skb, ga->len);
	dlen = sizeof(*ga) - ga->len;

	if (attrtype > app->app->maxattr)
		return 0;

	switch (ga->event) {
	case GARP_LEAVE_ALL:
		if (dlen != 0)
			return -1;
		garp_gid_event(app, GARP_EVENT_R_LEAVE_EMPTY);
		return 0;
	case GARP_JOIN_EMPTY:
		event = GARP_EVENT_R_JOIN_EMPTY;
		break;
	case GARP_JOIN_IN:
		event = GARP_EVENT_R_JOIN_IN;
		break;
	case GARP_LEAVE_EMPTY:
		event = GARP_EVENT_R_LEAVE_EMPTY;
		break;
	case GARP_EMPTY:
		event = GARP_EVENT_R_EMPTY;
		break;
	default:
		return 0;
	}

	if (dlen == 0)
		return -1;
	attr = garp_attr_lookup(app, ga->data, dlen, attrtype);
	if (attr == NULL)
		return 0;
	garp_attr_event(app, attr, event);
	return 0;
}

static int garp_pdu_parse_msg(struct garp_applicant *app, struct sk_buff *skb)
{
	const struct garp_msg_hdr *gm;

	if (!pskb_may_pull(skb, sizeof(*gm)))
		return -1;
	gm = (struct garp_msg_hdr *)skb->data;
	if (gm->attrtype == 0)
		return -1;
	skb_pull(skb, sizeof(*gm));

	while (skb->len > 0) {
		if (garp_pdu_parse_attr(app, skb, gm->attrtype) < 0)
			return -1;
		if (garp_pdu_parse_end_mark(skb) < 0)
			break;
	}
	return 0;
}

static void garp_pdu_rcv(const struct stp_proto *proto, struct sk_buff *skb,
			 struct net_device *dev)
{
	struct garp_application *appl = proto->data;
	struct garp_port *port;
	struct garp_applicant *app;
	const struct garp_pdu_hdr *gp;

	port = rcu_dereference(dev->garp_port);
	if (!port)
		goto err;
	app = rcu_dereference(port->applicants[appl->type]);
	if (!app)
		goto err;

	if (!pskb_may_pull(skb, sizeof(*gp)))
		goto err;
	gp = (struct garp_pdu_hdr *)skb->data;
	if (get_unaligned(&gp->protocol) != htons(GARP_PROTOCOL_ID))
		goto err;
	skb_pull(skb, sizeof(*gp));

	spin_lock(&app->lock);
	while (skb->len > 0) {
		if (garp_pdu_parse_msg(app, skb) < 0)
			break;
		if (garp_pdu_parse_end_mark(skb) < 0)
			break;
	}
	spin_unlock(&app->lock);
err:
	kfree_skb(skb);
}

static int garp_init_port(struct net_device *dev)
{
	struct garp_port *port;

	port = kzalloc(sizeof(*port), GFP_KERNEL);
	if (!port)
		return -ENOMEM;
	rcu_assign_pointer(dev->garp_port, port);
	return 0;
}

static void garp_release_port(struct net_device *dev)
{
	struct garp_port *port = rtnl_dereference(dev->garp_port);
	unsigned int i;

	for (i = 0; i <= GARP_APPLICATION_MAX; i++) {
		if (rtnl_dereference(port->applicants[i]))
			return;
	}
	RCU_INIT_POINTER(dev->garp_port, NULL);
	kfree_rcu(port, rcu);
}

int garp_init_applicant(struct net_device *dev, struct garp_application *appl)
{
	struct garp_applicant *app;
	int err;

	ASSERT_RTNL();

	if (!rtnl_dereference(dev->garp_port)) {
		err = garp_init_port(dev);
		if (err < 0)
			goto err1;
	}

	err = -ENOMEM;
	app = kzalloc(sizeof(*app), GFP_KERNEL);
	if (!app)
		goto err2;

	err = dev_mc_add(dev, appl->proto.group_address);
	if (err < 0)
		goto err3;

	app->dev = dev;
	app->app = appl;
	app->gid = RB_ROOT;
	spin_lock_init(&app->lock);
	skb_queue_head_init(&app->queue);
	rcu_assign_pointer(dev->garp_port->applicants[appl->type], app);
	timer_setup(&app->join_timer, garp_join_timer, 0);
	garp_join_timer_arm(app);
	return 0;

err3:
	kfree(app);
err2:
	garp_release_port(dev);
err1:
	return err;
}
EXPORT_SYMBOL_GPL(garp_init_applicant);

void garp_uninit_applicant(struct net_device *dev, struct garp_application *appl)
{
	struct garp_port *port = rtnl_dereference(dev->garp_port);
	struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);

	ASSERT_RTNL();

	RCU_INIT_POINTER(port->applicants[appl->type], NULL);

	/* Delete timer and generate a final TRANSMIT_PDU event to flush out
	 * all pending messages before the applicant is gone. */
	timer_shutdown_sync(&app->join_timer);

	spin_lock_bh(&app->lock);
	garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
	garp_attr_destroy_all(app);
	garp_pdu_queue(app);
	spin_unlock_bh(&app->lock);

	garp_queue_xmit(app);

	dev_mc_del(dev, appl->proto.group_address);
	kfree_rcu(app, rcu);
	garp_release_port(dev);
}
EXPORT_SYMBOL_GPL(garp_uninit_applicant);

int garp_register_application(struct garp_application *appl)
{
	appl->proto.rcv = garp_pdu_rcv;
	appl->proto.data = appl;
	return stp_proto_register(&appl->proto);
}
EXPORT_SYMBOL_GPL(garp_register_application);

void garp_unregister_application(struct garp_application *appl)
{
	stp_proto_unregister(&appl->proto);
}
EXPORT_SYMBOL_GPL(garp_unregister_application);
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
42ca63f9 YY	206	static void garp_attr_destroy_all(struct garp_applicant *app)
	207	{
	208	struct rb_node node, next;
	209	struct garp_attr *attr;
	210
	211	for (node = rb_first(&app->gid);
	212	next = node ? rb_next(node) : NULL, node != NULL;
	213	node = next) {
	214	attr = rb_entry(node, struct garp_attr, node);
	215	garp_attr_destroy(app, attr);
	216	}
	217	}
	218
eca9ebac PM	219	static int garp_pdu_init(struct garp_applicant *app)
	220	{
	221	struct sk_buff *skb;
	222	struct garp_pdu_hdr *gp;
	223
	224	#define LLC_RESERVE sizeof(struct llc_pdu_un)
	225	skb = alloc_skb(app->dev->mtu + LL_RESERVED_SPACE(app->dev),
	226	GFP_ATOMIC);
	227	if (!skb)
	228	return -ENOMEM;
	229
	230	skb->dev = app->dev;
	231	skb->protocol = htons(ETH_P_802_2);
	232	skb_reserve(skb, LL_RESERVED_SPACE(app->dev) + LLC_RESERVE);
	233
4df864c1	234	gp = __skb_put(skb, sizeof(*gp));
eca9ebac PM	235	put_unaligned(htons(GARP_PROTOCOL_ID), &gp->protocol);
	236
	237	app->pdu = skb;
	238	return 0;
	239	}
	240
	241	static int garp_pdu_append_end_mark(struct garp_applicant *app)
	242	{
	243	if (skb_tailroom(app->pdu) < sizeof(u8))
	244	return -1;
de77b966	245	__skb_put_u8(app->pdu, GARP_END_MARK);
eca9ebac PM	246	return 0;
	247	}
	248
	249	static void garp_pdu_queue(struct garp_applicant *app)
	250	{
	251	if (!app->pdu)
	252	return;
	253
	254	garp_pdu_append_end_mark(app);
	255	garp_pdu_append_end_mark(app);
	256
	257	llc_pdu_header_init(app->pdu, LLC_PDU_TYPE_U, LLC_SAP_BSPAN,
	258	LLC_SAP_BSPAN, LLC_PDU_CMD);
	259	llc_pdu_init_as_ui_cmd(app->pdu);
	260	llc_mac_hdr_init(app->pdu, app->dev->dev_addr,
	261	app->app->proto.group_address);
	262
	263	skb_queue_tail(&app->queue, app->pdu);
	264	app->pdu = NULL;
	265	}
	266
	267	static void garp_queue_xmit(struct garp_applicant *app)
	268	{
	269	struct sk_buff *skb;
	270
	271	while ((skb = skb_dequeue(&app->queue)))
	272	dev_queue_xmit(skb);
	273	}
	274
	275	static int garp_pdu_append_msg(struct garp_applicant *app, u8 attrtype)
	276	{
	277	struct garp_msg_hdr *gm;
	278
	279	if (skb_tailroom(app->pdu) < sizeof(*gm))
	280	return -1;
4df864c1	281	gm = __skb_put(app->pdu, sizeof(*gm));
eca9ebac PM	282	gm->attrtype = attrtype;
	283	garp_cb(app->pdu)->cur_type = attrtype;
	284	return 0;
	285	}
	286
	287	static int garp_pdu_append_attr(struct garp_applicant *app,
	288	const struct garp_attr *attr,
	289	enum garp_attr_event event)
	290	{
	291	struct garp_attr_hdr *ga;
	292	unsigned int len;
	293	int err;
	294	again:
	295	if (!app->pdu) {
	296	err = garp_pdu_init(app);
	297	if (err < 0)
	298	return err;
	299	}
	300
	301	if (garp_cb(app->pdu)->cur_type != attr->type) {
	302	if (garp_cb(app->pdu)->cur_type &&
	303	garp_pdu_append_end_mark(app) < 0)
	304	goto queue;
	305	if (garp_pdu_append_msg(app, attr->type) < 0)
	306	goto queue;
	307	}
	308
	309	len = sizeof(*ga) + attr->dlen;
	310	if (skb_tailroom(app->pdu) < len)
	311	goto queue;
4df864c1	312	ga = __skb_put(app->pdu, len);
eca9ebac PM	313	ga->len = len;
	314	ga->event = event;
	315	memcpy(ga->data, attr->data, attr->dlen);
	316	return 0;
	317
	318	queue:
	319	garp_pdu_queue(app);
	320	goto again;
	321	}
	322
	323	static void garp_attr_event(struct garp_applicant *app,
	324	struct garp_attr *attr, enum garp_event event)
	325	{
	326	enum garp_applicant_state state;
	327
	328	state = garp_applicant_state_table[attr->state][event].state;
	329	if (state == GARP_APPLICANT_INVALID)
	330	return;
	331
	332	switch (garp_applicant_state_table[attr->state][event].action) {
	333	case GARP_ACTION_NONE:
	334	break;
	335	case GARP_ACTION_S_JOIN_IN:
51ce7ec9 PM	336	/* When appending the attribute fails, don't update state in
	337	* order to retry on next TRANSMIT_PDU event. */
	338	if (garp_pdu_append_attr(app, attr, GARP_JOIN_IN) < 0)
	339	return;
eca9ebac PM	340	break;
	341	case GARP_ACTION_S_LEAVE_EMPTY:
	342	garp_pdu_append_attr(app, attr, GARP_LEAVE_EMPTY);
	343	/* As a pure applicant, sending a leave message implies that
	344	* the attribute was unregistered and can be destroyed. */
	345	garp_attr_destroy(app, attr);
	346	return;
	347	default:
	348	WARN_ON(1);
	349	}
	350
	351	attr->state = state;
	352	}
	353
	354	int garp_request_join(const struct net_device *dev,
	355	const struct garp_application *appl,
	356	const void *data, u8 len, u8 type)
	357	{
3cc77ec7 ED	358	struct garp_port *port = rtnl_dereference(dev->garp_port);
3cc77ec7 ED	359	struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
eca9ebac PM	360	struct garp_attr *attr;
	361
	362	spin_lock_bh(&app->lock);
	363	attr = garp_attr_create(app, data, len, type);
	364	if (!attr) {
	365	spin_unlock_bh(&app->lock);
	366	return -ENOMEM;
	367	}
	368	garp_attr_event(app, attr, GARP_EVENT_REQ_JOIN);
	369	spin_unlock_bh(&app->lock);
	370	return 0;
	371	}
	372	EXPORT_SYMBOL_GPL(garp_request_join);
	373
	374	void garp_request_leave(const struct net_device *dev,
	375	const struct garp_application *appl,
	376	const void *data, u8 len, u8 type)
	377	{
3cc77ec7 ED	378	struct garp_port *port = rtnl_dereference(dev->garp_port);
3cc77ec7 ED	379	struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
eca9ebac PM	380	struct garp_attr *attr;
	381
	382	spin_lock_bh(&app->lock);
	383	attr = garp_attr_lookup(app, data, len, type);
	384	if (!attr) {
	385	spin_unlock_bh(&app->lock);
	386	return;
	387	}
	388	garp_attr_event(app, attr, GARP_EVENT_REQ_LEAVE);
	389	spin_unlock_bh(&app->lock);
	390	}
	391	EXPORT_SYMBOL_GPL(garp_request_leave);
	392
	393	static void garp_gid_event(struct garp_applicant *app, enum garp_event event)
	394	{
	395	struct rb_node node, next;
	396	struct garp_attr *attr;
	397
	398	for (node = rb_first(&app->gid);
	399	next = node ? rb_next(node) : NULL, node != NULL;
	400	node = next) {
	401	attr = rb_entry(node, struct garp_attr, node);
	402	garp_attr_event(app, attr, event);
	403	}
	404	}
	405
	406	static void garp_join_timer_arm(struct garp_applicant *app)
	407	{
	408	unsigned long delay;
	409
8032bf12	410	delay = get_random_u32_below(msecs_to_jiffies(garp_join_time));
eca9ebac PM	411	mod_timer(&app->join_timer, jiffies + delay);
	412	}
	413
e99e88a9	414	static void garp_join_timer(struct timer_list *t)
eca9ebac	415	{
e99e88a9	416	struct garp_applicant *app = from_timer(app, t, join_timer);
eca9ebac PM	417
	418	spin_lock(&app->lock);
	419	garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
	420	garp_pdu_queue(app);
	421	spin_unlock(&app->lock);
	422
	423	garp_queue_xmit(app);
	424	garp_join_timer_arm(app);
	425	}
	426
	427	static int garp_pdu_parse_end_mark(struct sk_buff *skb)
	428	{
	429	if (!pskb_may_pull(skb, sizeof(u8)))
	430	return -1;
	431	if (*skb->data == GARP_END_MARK) {
	432	skb_pull(skb, sizeof(u8));
	433	return -1;
	434	}
	435	return 0;
	436	}
	437
	438	static int garp_pdu_parse_attr(struct garp_applicant app, struct sk_buff skb,
	439	u8 attrtype)
	440	{
	441	const struct garp_attr_hdr *ga;
	442	struct garp_attr *attr;
	443	enum garp_event event;
	444	unsigned int dlen;
	445
	446	if (!pskb_may_pull(skb, sizeof(*ga)))
	447	return -1;
	448	ga = (struct garp_attr_hdr *)skb->data;
	449	if (ga->len < sizeof(*ga))
	450	return -1;
	451
	452	if (!pskb_may_pull(skb, ga->len))
	453	return -1;
	454	skb_pull(skb, ga->len);
	455	dlen = sizeof(*ga) - ga->len;
	456
	457	if (attrtype > app->app->maxattr)
	458	return 0;
	459
	460	switch (ga->event) {
	461	case GARP_LEAVE_ALL:
	462	if (dlen != 0)
	463	return -1;
	464	garp_gid_event(app, GARP_EVENT_R_LEAVE_EMPTY);
	465	return 0;
	466	case GARP_JOIN_EMPTY:
	467	event = GARP_EVENT_R_JOIN_EMPTY;
	468	break;
	469	case GARP_JOIN_IN:
	470	event = GARP_EVENT_R_JOIN_IN;
	471	break;
	472	case GARP_LEAVE_EMPTY:
	473	event = GARP_EVENT_R_LEAVE_EMPTY;
	474	break;
	475	case GARP_EMPTY:
	476	event = GARP_EVENT_R_EMPTY;
	477	break;
	478	default:
	479	return 0;
	480	}
481
482	if (dlen == 0)
483	return -1;
484	attr = garp_attr_lookup(app, ga->data, dlen, attrtype);
485	if (attr == NULL)
486	return 0;
487	garp_attr_event(app, attr, event);
488	return 0;
489	}
490
491	static int garp_pdu_parse_msg(struct garp_applicant app, struct sk_buff skb)
492	{
493	const struct garp_msg_hdr *gm;
494
495	if (!pskb_may_pull(skb, sizeof(*gm)))
496	return -1;
497	gm = (struct garp_msg_hdr *)skb->data;
498	if (gm->attrtype == 0)
499	return -1;
500	skb_pull(skb, sizeof(*gm));
501
502	while (skb->len > 0) {
503	if (garp_pdu_parse_attr(app, skb, gm->attrtype) < 0)
504	return -1;
505	if (garp_pdu_parse_end_mark(skb) < 0)
506	break;
507	}
508	return 0;
509	}
510
511	static void garp_pdu_rcv(const struct stp_proto proto, struct sk_buff skb,
512	struct net_device *dev)
513	{
514	struct garp_application *appl = proto->data;
515	struct garp_port *port;
516	struct garp_applicant *app;
517	const struct garp_pdu_hdr *gp;
518
519	port = rcu_dereference(dev->garp_port);
520	if (!port)
521	goto err;
522	app = rcu_dereference(port->applicants[appl->type]);
523	if (!app)
524	goto err;
525
526	if (!pskb_may_pull(skb, sizeof(*gp)))
527	goto err;
528	gp = (struct garp_pdu_hdr *)skb->data;
529	if (get_unaligned(&gp->protocol) != htons(GARP_PROTOCOL_ID))
530	goto err;
531	skb_pull(skb, sizeof(*gp));
532
533	spin_lock(&app->lock);
534	while (skb->len > 0) {
535	if (garp_pdu_parse_msg(app, skb) < 0)
536	break;
537	if (garp_pdu_parse_end_mark(skb) < 0)
538	break;
539	}
540	spin_unlock(&app->lock);
541	err:
542	kfree_skb(skb);
543	}
544
545	static int garp_init_port(struct net_device *dev)
546	{
547	struct garp_port *port;
548
549	port = kzalloc(sizeof(*port), GFP_KERNEL);
550	if (!port)
551	return -ENOMEM;
552	rcu_assign_pointer(dev->garp_port, port);
553	return 0;
554	}
555
556	static void garp_release_port(struct net_device *dev)
557	{
3cc77ec7	558	struct garp_port *port = rtnl_dereference(dev->garp_port);
eca9ebac PM	559	unsigned int i;
	560
	561	for (i = 0; i <= GARP_APPLICATION_MAX; i++) {
3cc77ec7	562	if (rtnl_dereference(port->applicants[i]))
eca9ebac PM	563	return;
eca9ebac PM	564	}
a9b3cd7f	565	RCU_INIT_POINTER(dev->garp_port, NULL);
0a384b22	566	kfree_rcu(port, rcu);
eca9ebac PM	567	}
	568
	569	int garp_init_applicant(struct net_device dev, struct garp_application appl)
	570	{
	571	struct garp_applicant *app;
	572	int err;
	573
	574	ASSERT_RTNL();
	575
3cc77ec7	576	if (!rtnl_dereference(dev->garp_port)) {
eca9ebac PM	577	err = garp_init_port(dev);
	578	if (err < 0)
	579	goto err1;
	580	}
	581
	582	err = -ENOMEM;
	583	app = kzalloc(sizeof(*app), GFP_KERNEL);
	584	if (!app)
	585	goto err2;
	586
22bedad3	587	err = dev_mc_add(dev, appl->proto.group_address);
eca9ebac PM	588	if (err < 0)
	589	goto err3;
	590
	591	app->dev = dev;
	592	app->app = appl;
	593	app->gid = RB_ROOT;
	594	spin_lock_init(&app->lock);
	595	skb_queue_head_init(&app->queue);
	596	rcu_assign_pointer(dev->garp_port->applicants[appl->type], app);
e99e88a9	597	timer_setup(&app->join_timer, garp_join_timer, 0);
eca9ebac PM	598	garp_join_timer_arm(app);
	599	return 0;
	600
	601	err3:
	602	kfree(app);
	603	err2:
	604	garp_release_port(dev);
	605	err1:
	606	return err;
	607	}
	608	EXPORT_SYMBOL_GPL(garp_init_applicant);
	609
	610	void garp_uninit_applicant(struct net_device dev, struct garp_application appl)
	611	{
3cc77ec7 ED	612	struct garp_port *port = rtnl_dereference(dev->garp_port);
3cc77ec7 ED	613	struct garp_applicant *app = rtnl_dereference(port->applicants[appl->type]);
eca9ebac PM	614
	615	ASSERT_RTNL();
	616
a9b3cd7f	617	RCU_INIT_POINTER(port->applicants[appl->type], NULL);
eca9ebac PM	618
	619	/* Delete timer and generate a final TRANSMIT_PDU event to flush out
	620	* all pending messages before the applicant is gone. */
292a089d	621	timer_shutdown_sync(&app->join_timer);
cfbe800b CW	622
cfbe800b CW	623	spin_lock_bh(&app->lock);
eca9ebac	624	garp_gid_event(app, GARP_EVENT_TRANSMIT_PDU);
42ca63f9	625	garp_attr_destroy_all(app);
eca9ebac	626	garp_pdu_queue(app);
cfbe800b CW	627	spin_unlock_bh(&app->lock);
cfbe800b CW	628
eca9ebac PM	629	garp_queue_xmit(app);
eca9ebac PM	630
22bedad3	631	dev_mc_del(dev, appl->proto.group_address);
0a384b22	632	kfree_rcu(app, rcu);
eca9ebac PM	633	garp_release_port(dev);
	634	}
	635	EXPORT_SYMBOL_GPL(garp_uninit_applicant);
	636
	637	int garp_register_application(struct garp_application *appl)
	638	{
	639	appl->proto.rcv = garp_pdu_rcv;
	640	appl->proto.data = appl;
	641	return stp_proto_register(&appl->proto);
	642	}
	643	EXPORT_SYMBOL_GPL(garp_register_application);
	644
	645	void garp_unregister_application(struct garp_application *appl)
	646	{
	647	stp_proto_unregister(&appl->proto);
	648	}
	649	EXPORT_SYMBOL_GPL(garp_unregister_application);