text: /*
   *	IEEE 802.1Q Multiple Registration Protocol (MRP)
   *
   *	Copyright (c) 2012 Massachusetts Institute of Technology
   *
   *	Adapted from code in net/802/garp.c
   *	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/slab.h>
  #include <linux/module.h>
  #include <net/mrp.h>
  #include <asm/unaligned.h>
  
  static unsigned int mrp_join_time __read_mostly = 200;
  module_param(mrp_join_time, uint, 0644);
  MODULE_PARM_DESC(mrp_join_time, "Join time in ms (default 200ms)");
  
  static unsigned int mrp_periodic_time __read_mostly = 1000;
  module_param(mrp_periodic_time, uint, 0644);
  MODULE_PARM_DESC(mrp_periodic_time, "Periodic time in ms (default 1s)");
  
  MODULE_LICENSE("GPL");
  
  static const u8
  mrp_applicant_state_table[MRP_APPLICANT_MAX + 1][MRP_EVENT_MAX + 1] = {
  	[MRP_APPLICANT_VO] = {
  		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
  		[MRP_EVENT_JOIN]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_LV]		= MRP_APPLICANT_VO,
  		[MRP_EVENT_TX]		= MRP_APPLICANT_VO,
  		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_VO,
  		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_AO,
  		[MRP_EVENT_R_IN]	= MRP_APPLICANT_VO,
  		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_VO,
  		[MRP_EVENT_R_MT]	= MRP_APPLICANT_VO,
  		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VO,
  		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VO,
  		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VO,
  		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_VO,
  	},
  	[MRP_APPLICANT_VP] = {
  		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
  		[MRP_EVENT_JOIN]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_LV]		= MRP_APPLICANT_VO,
  		[MRP_EVENT_TX]		= MRP_APPLICANT_AA,
  		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_AP,
  		[MRP_EVENT_R_IN]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_R_MT]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_VP,
  	},
  	[MRP_APPLICANT_VN] = {
  		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
  		[MRP_EVENT_JOIN]	= MRP_APPLICANT_VN,
  		[MRP_EVENT_LV]		= MRP_APPLICANT_LA,
  		[MRP_EVENT_TX]		= MRP_APPLICANT_AN,
  		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_VN,
  		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_VN,
  		[MRP_EVENT_R_IN]	= MRP_APPLICANT_VN,
  		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_VN,
  		[MRP_EVENT_R_MT]	= MRP_APPLICANT_VN,
  		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VN,
  		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VN,
  		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VN,
  		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_VN,
  	},
  	[MRP_APPLICANT_AN] = {
  		[MRP_EVENT_NEW]		= MRP_APPLICANT_AN,
  		[MRP_EVENT_JOIN]	= MRP_APPLICANT_AN,
  		[MRP_EVENT_LV]		= MRP_APPLICANT_LA,
  		[MRP_EVENT_TX]		= MRP_APPLICANT_QA,
  		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_AN,
  		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_AN,
  		[MRP_EVENT_R_IN]	= MRP_APPLICANT_AN,
  		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_AN,
  		[MRP_EVENT_R_MT]	= MRP_APPLICANT_AN,
  		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VN,
  		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VN,
  		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VN,
  		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_AN,
  	},
  	[MRP_APPLICANT_AA] = {
  		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
  		[MRP_EVENT_JOIN]	= MRP_APPLICANT_AA,
  		[MRP_EVENT_LV]		= MRP_APPLICANT_LA,
  		[MRP_EVENT_TX]		= MRP_APPLICANT_QA,
  		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_AA,
  		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_QA,
  		[MRP_EVENT_R_IN]	= MRP_APPLICANT_AA,
  		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_AA,
  		[MRP_EVENT_R_MT]	= MRP_APPLICANT_AA,
  		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_AA,
  	},
  	[MRP_APPLICANT_QA] = {
  		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
  		[MRP_EVENT_JOIN]	= MRP_APPLICANT_QA,
  		[MRP_EVENT_LV]		= MRP_APPLICANT_LA,
  		[MRP_EVENT_TX]		= MRP_APPLICANT_QA,
  		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_QA,
  		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_QA,
  		[MRP_EVENT_R_IN]	= MRP_APPLICANT_QA,
  		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_AA,
  		[MRP_EVENT_R_MT]	= MRP_APPLICANT_AA,
  		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_AA,
  	},
  	[MRP_APPLICANT_LA] = {
  		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
  		[MRP_EVENT_JOIN]	= MRP_APPLICANT_AA,
  		[MRP_EVENT_LV]		= MRP_APPLICANT_LA,
  		[MRP_EVENT_TX]		= MRP_APPLICANT_VO,
  		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_LA,
  		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_LA,
  		[MRP_EVENT_R_IN]	= MRP_APPLICANT_LA,
  		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_LA,
  		[MRP_EVENT_R_MT]	= MRP_APPLICANT_LA,
  		[MRP_EVENT_R_LV]	= MRP_APPLICANT_LA,
  		[MRP_EVENT_R_LA]	= MRP_APPLICANT_LA,
  		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_LA,
  		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_LA,
  	},
  	[MRP_APPLICANT_AO] = {
  		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
  		[MRP_EVENT_JOIN]	= MRP_APPLICANT_AP,
  		[MRP_EVENT_LV]		= MRP_APPLICANT_AO,
  		[MRP_EVENT_TX]		= MRP_APPLICANT_AO,
  		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_AO,
  		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_QO,
  		[MRP_EVENT_R_IN]	= MRP_APPLICANT_AO,
  		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_AO,
  		[MRP_EVENT_R_MT]	= MRP_APPLICANT_AO,
  		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VO,
  		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VO,
  		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VO,
  		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_AO,
  	},
  	[MRP_APPLICANT_QO] = {
  		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
  		[MRP_EVENT_JOIN]	= MRP_APPLICANT_QP,
  		[MRP_EVENT_LV]		= MRP_APPLICANT_QO,
  		[MRP_EVENT_TX]		= MRP_APPLICANT_QO,
  		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_QO,
  		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_QO,
  		[MRP_EVENT_R_IN]	= MRP_APPLICANT_QO,
  		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_AO,
  		[MRP_EVENT_R_MT]	= MRP_APPLICANT_AO,
  		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VO,
  		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VO,
  		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VO,
  		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_QO,
  	},
  	[MRP_APPLICANT_AP] = {
  		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
  		[MRP_EVENT_JOIN]	= MRP_APPLICANT_AP,
  		[MRP_EVENT_LV]		= MRP_APPLICANT_AO,
  		[MRP_EVENT_TX]		= MRP_APPLICANT_QA,
  		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_AP,
  		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_QP,
  		[MRP_EVENT_R_IN]	= MRP_APPLICANT_AP,
  		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_AP,
  		[MRP_EVENT_R_MT]	= MRP_APPLICANT_AP,
  		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_AP,
  	},
  	[MRP_APPLICANT_QP] = {
  		[MRP_EVENT_NEW]		= MRP_APPLICANT_VN,
  		[MRP_EVENT_JOIN]	= MRP_APPLICANT_QP,
  		[MRP_EVENT_LV]		= MRP_APPLICANT_QO,
  		[MRP_EVENT_TX]		= MRP_APPLICANT_QP,
  		[MRP_EVENT_R_NEW]	= MRP_APPLICANT_QP,
  		[MRP_EVENT_R_JOIN_IN]	= MRP_APPLICANT_QP,
  		[MRP_EVENT_R_IN]	= MRP_APPLICANT_QP,
  		[MRP_EVENT_R_JOIN_MT]	= MRP_APPLICANT_AP,
  		[MRP_EVENT_R_MT]	= MRP_APPLICANT_AP,
  		[MRP_EVENT_R_LV]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_R_LA]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_REDECLARE]	= MRP_APPLICANT_VP,
  		[MRP_EVENT_PERIODIC]	= MRP_APPLICANT_AP,
  	},
  };
  
  static const u8
  mrp_tx_action_table[MRP_APPLICANT_MAX + 1] = {
  	[MRP_APPLICANT_VO] = MRP_TX_ACTION_S_IN_OPTIONAL,
  	[MRP_APPLICANT_VP] = MRP_TX_ACTION_S_JOIN_IN,
  	[MRP_APPLICANT_VN] = MRP_TX_ACTION_S_NEW,
  	[MRP_APPLICANT_AN] = MRP_TX_ACTION_S_NEW,
  	[MRP_APPLICANT_AA] = MRP_TX_ACTION_S_JOIN_IN,
  	[MRP_APPLICANT_QA] = MRP_TX_ACTION_S_JOIN_IN_OPTIONAL,
  	[MRP_APPLICANT_LA] = MRP_TX_ACTION_S_LV,
  	[MRP_APPLICANT_AO] = MRP_TX_ACTION_S_IN_OPTIONAL,
  	[MRP_APPLICANT_QO] = MRP_TX_ACTION_S_IN_OPTIONAL,
  	[MRP_APPLICANT_AP] = MRP_TX_ACTION_S_JOIN_IN,
  	[MRP_APPLICANT_QP] = MRP_TX_ACTION_S_IN_OPTIONAL,
  };
  
  static void mrp_attrvalue_inc(void *value, u8 len)
  {
  	u8 *v = (u8 *)value;
  
  	/* Add 1 to the last byte. If it becomes zero,
  	 * go to the previous byte and repeat.
  	 */
  	while (len > 0 && !++v[--len])
  		;
  }
  
  static int mrp_attr_cmp(const struct mrp_attr *attr,
  			 const void *value, u8 len, u8 type)
  {
  	if (attr->type != type)
  		return attr->type - type;
  	if (attr->len != len)
  		return attr->len - len;
  	return memcmp(attr->value, value, len);
  }
  
  static struct mrp_attr *mrp_attr_lookup(const struct mrp_applicant *app,
  					const void *value, u8 len, u8 type)
  {
  	struct rb_node *parent = app->mad.rb_node;
  	struct mrp_attr *attr;
  	int d;
  
  	while (parent) {
  		attr = rb_entry(parent, struct mrp_attr, node);
  		d = mrp_attr_cmp(attr, value, len, type);
  		if (d > 0)
  			parent = parent->rb_left;
  		else if (d < 0)
  			parent = parent->rb_right;
  		else
  			return attr;
  	}
  	return NULL;
  }
  
  static struct mrp_attr *mrp_attr_create(struct mrp_applicant *app,
  					const void *value, u8 len, u8 type)
  {
  	struct rb_node *parent = NULL, **p = &app->mad.rb_node;
  	struct mrp_attr *attr;
  	int d;
  
  	while (*p) {
  		parent = *p;
  		attr = rb_entry(parent, struct mrp_attr, node);
  		d = mrp_attr_cmp(attr, value, 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 = MRP_APPLICANT_VO;
  	attr->type  = type;
  	attr->len   = len;
  	memcpy(attr->value, value, len);
  
  	rb_link_node(&attr->node, parent, p);
  	rb_insert_color(&attr->node, &app->mad);
  	return attr;
  }
  
  static void mrp_attr_destroy(struct mrp_applicant *app, struct mrp_attr *attr)
  {
  	rb_erase(&attr->node, &app->mad);
  	kfree(attr);
  }
  
  static int mrp_pdu_init(struct mrp_applicant *app)
  {
  	struct sk_buff *skb;
  	struct mrp_pdu_hdr *ph;
  
  	skb = alloc_skb(app->dev->mtu + LL_RESERVED_SPACE(app->dev),
  			GFP_ATOMIC);
  	if (!skb)
  		return -ENOMEM;
  
  	skb->dev = app->dev;
  	skb->protocol = app->app->pkttype.type;
  	skb_reserve(skb, LL_RESERVED_SPACE(app->dev));
  	skb_reset_network_header(skb);
  	skb_reset_transport_header(skb);
  
  	ph = __skb_put(skb, sizeof(*ph));
  	ph->version = app->app->version;
  
  	app->pdu = skb;
  	return 0;
  }
  
  static int mrp_pdu_append_end_mark(struct mrp_applicant *app)
  {
  	__be16 *endmark;
  
  	if (skb_tailroom(app->pdu) < sizeof(*endmark))
  		return -1;
  	endmark = __skb_put(app->pdu, sizeof(*endmark));
  	put_unaligned(MRP_END_MARK, endmark);
  	return 0;
  }
  
  static void mrp_pdu_queue(struct mrp_applicant *app)
  {
  	if (!app->pdu)
  		return;
  
  	if (mrp_cb(app->pdu)->mh)
  		mrp_pdu_append_end_mark(app);
  	mrp_pdu_append_end_mark(app);
  
  	dev_hard_header(app->pdu, app->dev, ntohs(app->app->pkttype.type),
  			app->app->group_address, app->dev->dev_addr,
  			app->pdu->len);
  
  	skb_queue_tail(&app->queue, app->pdu);
  	app->pdu = NULL;
  }
  
  static void mrp_queue_xmit(struct mrp_applicant *app)
  {
  	struct sk_buff *skb;
  
  	while ((skb = skb_dequeue(&app->queue)))
  		dev_queue_xmit(skb);
  }
  
  static int mrp_pdu_append_msg_hdr(struct mrp_applicant *app,
  				  u8 attrtype, u8 attrlen)
  {
  	struct mrp_msg_hdr *mh;
  
  	if (mrp_cb(app->pdu)->mh) {
  		if (mrp_pdu_append_end_mark(app) < 0)
  			return -1;
  		mrp_cb(app->pdu)->mh = NULL;
  		mrp_cb(app->pdu)->vah = NULL;
  	}
  
  	if (skb_tailroom(app->pdu) < sizeof(*mh))
  		return -1;
  	mh = __skb_put(app->pdu, sizeof(*mh));
  	mh->attrtype = attrtype;
  	mh->attrlen = attrlen;
  	mrp_cb(app->pdu)->mh = mh;
  	return 0;
  }
  
  static int mrp_pdu_append_vecattr_hdr(struct mrp_applicant *app,
  				      const void *firstattrvalue, u8 attrlen)
  {
  	struct mrp_vecattr_hdr *vah;
  
  	if (skb_tailroom(app->pdu) < sizeof(*vah) + attrlen)
  		return -1;
  	vah = __skb_put(app->pdu, sizeof(*vah) + attrlen);
  	put_unaligned(0, &vah->lenflags);
  	memcpy(vah->firstattrvalue, firstattrvalue, attrlen);
  	mrp_cb(app->pdu)->vah = vah;
  	memcpy(mrp_cb(app->pdu)->attrvalue, firstattrvalue, attrlen);
  	return 0;
  }
  
  static int mrp_pdu_append_vecattr_event(struct mrp_applicant *app,
  					const struct mrp_attr *attr,
  					enum mrp_vecattr_event vaevent)
  {
  	u16 len, pos;
  	u8 *vaevents;
  	int err;
  again:
  	if (!app->pdu) {
  		err = mrp_pdu_init(app);
  		if (err < 0)
  			return err;
  	}
  
  	/* If there is no Message header in the PDU, or the Message header is
  	 * for a different attribute type, add an EndMark (if necessary) and a
  	 * new Message header to the PDU.
  	 */
  	if (!mrp_cb(app->pdu)->mh ||
  	    mrp_cb(app->pdu)->mh->attrtype != attr->type ||
  	    mrp_cb(app->pdu)->mh->attrlen != attr->len) {
  		if (mrp_pdu_append_msg_hdr(app, attr->type, attr->len) < 0)
  			goto queue;
  	}
  
  	/* If there is no VectorAttribute header for this Message in the PDU,
  	 * or this attribute's value does not sequentially follow the previous
  	 * attribute's value, add a new VectorAttribute header to the PDU.
  	 */
  	if (!mrp_cb(app->pdu)->vah ||
  	    memcmp(mrp_cb(app->pdu)->attrvalue, attr->value, attr->len)) {
  		if (mrp_pdu_append_vecattr_hdr(app, attr->value, attr->len) < 0)
  			goto queue;
  	}
  
  	len = be16_to_cpu(get_unaligned(&mrp_cb(app->pdu)->vah->lenflags));
  	pos = len % 3;
  
  	/* Events are packed into Vectors in the PDU, three to a byte. Add a
  	 * byte to the end of the Vector if necessary.
  	 */
  	if (!pos) {
  		if (skb_tailroom(app->pdu) < sizeof(u8))
  			goto queue;
  		vaevents = __skb_put(app->pdu, sizeof(u8));
  	} else {
  		vaevents = (u8 *)(skb_tail_pointer(app->pdu) - sizeof(u8));
  	}
  
  	switch (pos) {
  	case 0:
  		*vaevents = vaevent * (__MRP_VECATTR_EVENT_MAX *
  				       __MRP_VECATTR_EVENT_MAX);
  		break;
  	case 1:
  		*vaevents += vaevent * __MRP_VECATTR_EVENT_MAX;
  		break;
  	case 2:
  		*vaevents += vaevent;
  		break;
  	default:
  		WARN_ON(1);
  	}
  
  	/* Increment the length of the VectorAttribute in the PDU, as well as
  	 * the value of the next attribute that would continue its Vector.
  	 */
  	put_unaligned(cpu_to_be16(++len), &mrp_cb(app->pdu)->vah->lenflags);
  	mrp_attrvalue_inc(mrp_cb(app->pdu)->attrvalue, attr->len);
  
  	return 0;
  
  queue:
  	mrp_pdu_queue(app);
  	goto again;
  }
  
  static void mrp_attr_event(struct mrp_applicant *app,
  			   struct mrp_attr *attr, enum mrp_event event)
  {
  	enum mrp_applicant_state state;
  
  	state = mrp_applicant_state_table[attr->state][event];
  	if (state == MRP_APPLICANT_INVALID) {
  		WARN_ON(1);
  		return;
  	}
  
  	if (event == MRP_EVENT_TX) {
  		/* When appending the attribute fails, don't update its state
  		 * in order to retry at the next TX event.
  		 */
  
  		switch (mrp_tx_action_table[attr->state]) {
  		case MRP_TX_ACTION_NONE:
  		case MRP_TX_ACTION_S_JOIN_IN_OPTIONAL:
  		case MRP_TX_ACTION_S_IN_OPTIONAL:
  			break;
  		case MRP_TX_ACTION_S_NEW:
  			if (mrp_pdu_append_vecattr_event(
  				    app, attr, MRP_VECATTR_EVENT_NEW) < 0)
  				return;
  			break;
  		case MRP_TX_ACTION_S_JOIN_IN:
  			if (mrp_pdu_append_vecattr_event(
  				    app, attr, MRP_VECATTR_EVENT_JOIN_IN) < 0)
  				return;
  			break;
  		case MRP_TX_ACTION_S_LV:
  			if (mrp_pdu_append_vecattr_event(
  				    app, attr, MRP_VECATTR_EVENT_LV) < 0)
  				return;
  			/* As a pure applicant, sending a leave message
  			 * implies that the attribute was unregistered and
  			 * can be destroyed.
  			 */
  			mrp_attr_destroy(app, attr);
  			return;
  		default:
  			WARN_ON(1);
  		}
  	}
  
  	attr->state = state;
  }
  
  int mrp_request_join(const struct net_device *dev,
  		     const struct mrp_application *appl,
  		     const void *value, u8 len, u8 type)
  {
  	struct mrp_port *port = rtnl_dereference(dev->mrp_port);
  	struct mrp_applicant *app = rtnl_dereference(
  		port->applicants[appl->type]);
  	struct mrp_attr *attr;
  
  	if (sizeof(struct mrp_skb_cb) + len >
  	    FIELD_SIZEOF(struct sk_buff, cb))
  		return -ENOMEM;
  
  	spin_lock_bh(&app->lock);
  	attr = mrp_attr_create(app, value, len, type);
  	if (!attr) {
  		spin_unlock_bh(&app->lock);
  		return -ENOMEM;
  	}
  	mrp_attr_event(app, attr, MRP_EVENT_JOIN);
  	spin_unlock_bh(&app->lock);
  	return 0;
  }
  EXPORT_SYMBOL_GPL(mrp_request_join);
  
  void mrp_request_leave(const struct net_device *dev,
  		       const struct mrp_application *appl,
  		       const void *value, u8 len, u8 type)
  {
  	struct mrp_port *port = rtnl_dereference(dev->mrp_port);
  	struct mrp_applicant *app = rtnl_dereference(
  		port->applicants[appl->type]);
  	struct mrp_attr *attr;
  
  	if (sizeof(struct mrp_skb_cb) + len >
  	    FIELD_SIZEOF(struct sk_buff, cb))
  		return;
  
  	spin_lock_bh(&app->lock);
  	attr = mrp_attr_lookup(app, value, len, type);
  	if (!attr) {
  		spin_unlock_bh(&app->lock);
  		return;
  	}
  	mrp_attr_event(app, attr, MRP_EVENT_LV);
  	spin_unlock_bh(&app->lock);
  }
  EXPORT_SYMBOL_GPL(mrp_request_leave);
  
  static void mrp_mad_event(struct mrp_applicant *app, enum mrp_event event)
  {
  	struct rb_node *node, *next;
  	struct mrp_attr *attr;
  
  	for (node = rb_first(&app->mad);
  	     next = node ? rb_next(node) : NULL, node != NULL;
  	     node = next) {
  		attr = rb_entry(node, struct mrp_attr, node);
  		mrp_attr_event(app, attr, event);
  	}
  }
  
  static void mrp_join_timer_arm(struct mrp_applicant *app)
  {
  	unsigned long delay;
  
  	delay = (u64)msecs_to_jiffies(mrp_join_time) * prandom_u32() >> 32;
  	mod_timer(&app->join_timer, jiffies + delay);
  }
  
  static void mrp_join_timer(struct timer_list *t)
  {
  	struct mrp_applicant *app = from_timer(app, t, join_timer);
  
  	spin_lock(&app->lock);
  	mrp_mad_event(app, MRP_EVENT_TX);
  	mrp_pdu_queue(app);
  	spin_unlock(&app->lock);
  
  	mrp_queue_xmit(app);
  	mrp_join_timer_arm(app);
  }
  
  static void mrp_periodic_timer_arm(struct mrp_applicant *app)
  {
  	mod_timer(&app->periodic_timer,
  		  jiffies + msecs_to_jiffies(mrp_periodic_time));
  }
  
  static void mrp_periodic_timer(struct timer_list *t)
  {
  	struct mrp_applicant *app = from_timer(app, t, periodic_timer);
  
  	spin_lock(&app->lock);
  	mrp_mad_event(app, MRP_EVENT_PERIODIC);
  	mrp_pdu_queue(app);
  	spin_unlock(&app->lock);
  
  	mrp_periodic_timer_arm(app);
  }
  
  static int mrp_pdu_parse_end_mark(struct sk_buff *skb, int *offset)
  {
  	__be16 endmark;
  
  	if (skb_copy_bits(skb, *offset, &endmark, sizeof(endmark)) < 0)
  		return -1;
  	if (endmark == MRP_END_MARK) {
  		*offset += sizeof(endmark);
  		return -1;
  	}
  	return 0;
  }
  
  static void mrp_pdu_parse_vecattr_event(struct mrp_applicant *app,
  					struct sk_buff *skb,
  					enum mrp_vecattr_event vaevent)
  {
  	struct mrp_attr *attr;
  	enum mrp_event event;
  
  	attr = mrp_attr_lookup(app, mrp_cb(skb)->attrvalue,
  			       mrp_cb(skb)->mh->attrlen,
  			       mrp_cb(skb)->mh->attrtype);
  	if (attr == NULL)
  		return;
  
  	switch (vaevent) {
  	case MRP_VECATTR_EVENT_NEW:
  		event = MRP_EVENT_R_NEW;
  		break;
  	case MRP_VECATTR_EVENT_JOIN_IN:
  		event = MRP_EVENT_R_JOIN_IN;
  		break;
  	case MRP_VECATTR_EVENT_IN:
  		event = MRP_EVENT_R_IN;
  		break;
  	case MRP_VECATTR_EVENT_JOIN_MT:
  		event = MRP_EVENT_R_JOIN_MT;
  		break;
  	case MRP_VECATTR_EVENT_MT:
  		event = MRP_EVENT_R_MT;
  		break;
  	case MRP_VECATTR_EVENT_LV:
  		event = MRP_EVENT_R_LV;
  		break;
  	default:
  		return;
  	}
  
  	mrp_attr_event(app, attr, event);
  }
  
  static int mrp_pdu_parse_vecattr(struct mrp_applicant *app,
  				 struct sk_buff *skb, int *offset)
  {
  	struct mrp_vecattr_hdr _vah;
  	u16 valen;
  	u8 vaevents, vaevent;
  
  	mrp_cb(skb)->vah = skb_header_pointer(skb, *offset, sizeof(_vah),
  					      &_vah);
  	if (!mrp_cb(skb)->vah)
  		return -1;
  	*offset += sizeof(_vah);
  
  	if (get_unaligned(&mrp_cb(skb)->vah->lenflags) &
  	    MRP_VECATTR_HDR_FLAG_LA)
  		mrp_mad_event(app, MRP_EVENT_R_LA);
  	valen = be16_to_cpu(get_unaligned(&mrp_cb(skb)->vah->lenflags) &
  			    MRP_VECATTR_HDR_LEN_MASK);
  
  	/* The VectorAttribute structure in a PDU carries event information
  	 * about one or more attributes having consecutive values. Only the
  	 * value for the first attribute is contained in the structure. So
  	 * we make a copy of that value, and then increment it each time we
  	 * advance to the next event in its Vector.
  	 */
  	if (sizeof(struct mrp_skb_cb) + mrp_cb(skb)->mh->attrlen >
  	    FIELD_SIZEOF(struct sk_buff, cb))
  		return -1;
  	if (skb_copy_bits(skb, *offset, mrp_cb(skb)->attrvalue,
  			  mrp_cb(skb)->mh->attrlen) < 0)
  		return -1;
  	*offset += mrp_cb(skb)->mh->attrlen;
  
  	/* In a VectorAttribute, the Vector contains events which are packed
  	 * three to a byte. We process one byte of the Vector at a time.
  	 */
  	while (valen > 0) {
  		if (skb_copy_bits(skb, *offset, &vaevents,
  				  sizeof(vaevents)) < 0)
  			return -1;
  		*offset += sizeof(vaevents);
  
  		/* Extract and process the first event. */
  		vaevent = vaevents / (__MRP_VECATTR_EVENT_MAX *
  				      __MRP_VECATTR_EVENT_MAX);
  		if (vaevent >= __MRP_VECATTR_EVENT_MAX) {
  			/* The byte is malformed; stop processing. */
  			return -1;
  		}
  		mrp_pdu_parse_vecattr_event(app, skb, vaevent);
  
  		/* If present, extract and process the second event. */
  		if (!--valen)
  			break;
  		mrp_attrvalue_inc(mrp_cb(skb)->attrvalue,
  				  mrp_cb(skb)->mh->attrlen);
  		vaevents %= (__MRP_VECATTR_EVENT_MAX *
  			     __MRP_VECATTR_EVENT_MAX);
  		vaevent = vaevents / __MRP_VECATTR_EVENT_MAX;
  		mrp_pdu_parse_vecattr_event(app, skb, vaevent);
  
  		/* If present, extract and process the third event. */
  		if (!--valen)
  			break;
  		mrp_attrvalue_inc(mrp_cb(skb)->attrvalue,
  				  mrp_cb(skb)->mh->attrlen);
  		vaevents %= __MRP_VECATTR_EVENT_MAX;
  		vaevent = vaevents;
  		mrp_pdu_parse_vecattr_event(app, skb, vaevent);
  	}
  	return 0;
  }
  
  static int mrp_pdu_parse_msg(struct mrp_applicant *app, struct sk_buff *skb,
  			     int *offset)
  {
  	struct mrp_msg_hdr _mh;
  
  	mrp_cb(skb)->mh = skb_header_pointer(skb, *offset, sizeof(_mh), &_mh);
  	if (!mrp_cb(skb)->mh)
  		return -1;
  	*offset += sizeof(_mh);
  
  	if (mrp_cb(skb)->mh->attrtype == 0 ||
  	    mrp_cb(skb)->mh->attrtype > app->app->maxattr ||
  	    mrp_cb(skb)->mh->attrlen == 0)
  		return -1;
  
  	while (skb->len > *offset) {
  		if (mrp_pdu_parse_end_mark(skb, offset) < 0)
  			break;
  		if (mrp_pdu_parse_vecattr(app, skb, offset) < 0)
  			return -1;
  	}
  	return 0;
  }
  
  static int mrp_rcv(struct sk_buff *skb, struct net_device *dev,
  		   struct packet_type *pt, struct net_device *orig_dev)
  {
  	struct mrp_application *appl = container_of(pt, struct mrp_application,
  						    pkttype);
  	struct mrp_port *port;
  	struct mrp_applicant *app;
  	struct mrp_pdu_hdr _ph;
  	const struct mrp_pdu_hdr *ph;
  	int offset = skb_network_offset(skb);
  
  	/* If the interface is in promiscuous mode, drop the packet if
  	 * it was unicast to another host.
  	 */
  	if (unlikely(skb->pkt_type == PACKET_OTHERHOST))
  		goto out;
  	skb = skb_share_check(skb, GFP_ATOMIC);
  	if (unlikely(!skb))
  		goto out;
  	port = rcu_dereference(dev->mrp_port);
  	if (unlikely(!port))
  		goto out;
  	app = rcu_dereference(port->applicants[appl->type]);
  	if (unlikely(!app))
  		goto out;
  
  	ph = skb_header_pointer(skb, offset, sizeof(_ph), &_ph);
  	if (!ph)
  		goto out;
  	offset += sizeof(_ph);
  
  	if (ph->version != app->app->version)
  		goto out;
  
  	spin_lock(&app->lock);
  	while (skb->len > offset) {
  		if (mrp_pdu_parse_end_mark(skb, &offset) < 0)
  			break;
  		if (mrp_pdu_parse_msg(app, skb, &offset) < 0)
  			break;
  	}
  	spin_unlock(&app->lock);
  out:
  	kfree_skb(skb);
  	return 0;
  }
  
  static int mrp_init_port(struct net_device *dev)
  {
  	struct mrp_port *port;
  
  	port = kzalloc(sizeof(*port), GFP_KERNEL);
  	if (!port)
  		return -ENOMEM;
  	rcu_assign_pointer(dev->mrp_port, port);
  	return 0;
  }
  
  static void mrp_release_port(struct net_device *dev)
  {
  	struct mrp_port *port = rtnl_dereference(dev->mrp_port);
  	unsigned int i;
  
  	for (i = 0; i <= MRP_APPLICATION_MAX; i++) {
  		if (rtnl_dereference(port->applicants[i]))
  			return;
  	}
  	RCU_INIT_POINTER(dev->mrp_port, NULL);
  	kfree_rcu(port, rcu);
  }
  
  int mrp_init_applicant(struct net_device *dev, struct mrp_application *appl)
  {
  	struct mrp_applicant *app;
  	int err;
  
  	ASSERT_RTNL();
  
  	if (!rtnl_dereference(dev->mrp_port)) {
  		err = mrp_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->group_address);
  	if (err < 0)
  		goto err3;
  
  	app->dev = dev;
  	app->app = appl;
  	app->mad = RB_ROOT;
  	spin_lock_init(&app->lock);
  	skb_queue_head_init(&app->queue);
  	rcu_assign_pointer(dev->mrp_port->applicants[appl->type], app);
  	timer_setup(&app->join_timer, mrp_join_timer, 0);
  	mrp_join_timer_arm(app);
  	timer_setup(&app->periodic_timer, mrp_periodic_timer, 0);
  	mrp_periodic_timer_arm(app);
  	return 0;
  
  err3:
  	kfree(app);
  err2:
  	mrp_release_port(dev);
  err1:
  	return err;
  }
  EXPORT_SYMBOL_GPL(mrp_init_applicant);
  
  void mrp_uninit_applicant(struct net_device *dev, struct mrp_application *appl)
  {
  	struct mrp_port *port = rtnl_dereference(dev->mrp_port);
  	struct mrp_applicant *app = rtnl_dereference(
  		port->applicants[appl->type]);
  
  	ASSERT_RTNL();
  
  	RCU_INIT_POINTER(port->applicants[appl->type], NULL);
  
  	/* Delete timer and generate a final TX event to flush out
  	 * all pending messages before the applicant is gone.
  	 */
  	del_timer_sync(&app->join_timer);
  	del_timer_sync(&app->periodic_timer);
  
  	spin_lock_bh(&app->lock);
  	mrp_mad_event(app, MRP_EVENT_TX);
  	mrp_pdu_queue(app);
  	spin_unlock_bh(&app->lock);
  
  	mrp_queue_xmit(app);
  
  	dev_mc_del(dev, appl->group_address);
  	kfree_rcu(app, rcu);
  	mrp_release_port(dev);
  }
  EXPORT_SYMBOL_GPL(mrp_uninit_applicant);
  
  int mrp_register_application(struct mrp_application *appl)
  {
  	appl->pkttype.func = mrp_rcv;
  	dev_add_pack(&appl->pkttype);
  	return 0;
  }
  EXPORT_SYMBOL_GPL(mrp_register_application);
  
  void mrp_unregister_application(struct mrp_application *appl)
  {
  	dev_remove_pack(&appl->pkttype);
  }
  EXPORT_SYMBOL_GPL(mrp_unregister_application);
  