/*
   *	Linux NET3:	Internet Group Management Protocol  [IGMP]
   *
   *	This code implements the IGMP protocol as defined in RFC1112. There has
   *	been a further revision of this protocol since which is now supported.
   *
   *	If you have trouble with this module be careful what gcc you have used,
   *	the older version didn't come out right using gcc 2.5.8, the newer one
   *	seems to fall out with gcc 2.6.2.
   *

   *	Authors:

   *		Alan Cox <alan@lxorguk.ukuu.org.uk>

   *
   *	This program is free software; you can redistribute it and/or
   *	modify it under the terms of the GNU General Public License
   *	as published by the Free Software Foundation; either version
   *	2 of the License, or (at your option) any later version.
   *
   *	Fixes:
   *
   *		Alan Cox	:	Added lots of __inline__ to optimise
   *					the memory usage of all the tiny little
   *					functions.
   *		Alan Cox	:	Dumped the header building experiment.
   *		Alan Cox	:	Minor tweaks ready for multicast routing
   *					and extended IGMP protocol.
   *		Alan Cox	:	Removed a load of inline directives. Gcc 2.5.8
   *					writes utterly bogus code otherwise (sigh)
   *					fixed IGMP loopback to behave in the manner
   *					desired by mrouted, fixed the fact it has been
   *					broken since 1.3.6 and cleaned up a few minor
   *					points.
   *
   *		Chih-Jen Chang	:	Tried to revise IGMP to Version 2
   *		Tsu-Sheng Tsao		E-mail: chihjenc@scf.usc.edu and tsusheng@scf.usc.edu

   *					The enhancements are mainly based on Steve Deering's

   * 					ipmulti-3.5 source code.
   *		Chih-Jen Chang	:	Added the igmp_get_mrouter_info and
   *		Tsu-Sheng Tsao		igmp_set_mrouter_info to keep track of
   *					the mrouted version on that device.
   *		Chih-Jen Chang	:	Added the max_resp_time parameter to
   *		Tsu-Sheng Tsao		igmp_heard_query(). Using this parameter
   *					to identify the multicast router version
   *					and do what the IGMP version 2 specified.
   *		Chih-Jen Chang	:	Added a timer to revert to IGMP V2 router
   *		Tsu-Sheng Tsao		if the specified time expired.
   *		Alan Cox	:	Stop IGMP from 0.0.0.0 being accepted.
   *		Alan Cox	:	Use GFP_ATOMIC in the right places.
   *		Christian Daudt :	igmp timer wasn't set for local group

   *					memberships but was being deleted,
   *					which caused a "del_timer() called

   *					from %p with timer not initialized
  "
   *					message (960131).

   *		Christian Daudt :	removed del_timer from

   *					igmp_timer_expire function (960205).
   *             Christian Daudt :       igmp_heard_report now only calls
   *                                     igmp_timer_expire if tm->running is
   *                                     true (960216).
   *		Malcolm Beattie :	ttl comparison wrong in igmp_rcv made
   *					igmp_heard_query never trigger. Expiry
   *					miscalculation fixed in igmp_heard_query
   *					and random() made to return unsigned to
   *					prevent negative expiry times.
   *		Alexey Kuznetsov:	Wrong group leaving behaviour, backport
   *					fix from pending 2.1.x patches.
   *		Alan Cox:		Forget to enable FDDI support earlier.
   *		Alexey Kuznetsov:	Fixed leaving groups on device down.
   *		Alexey Kuznetsov:	Accordance to igmp-v2-06 draft.
   *		David L Stevens:	IGMPv3 support, with help from
   *					Vinay Kulkarni
   */

  #include <linux/module.h>

  #include <linux/slab.h>

  #include <linux/uaccess.h>

  #include <linux/types.h>
  #include <linux/kernel.h>
  #include <linux/jiffies.h>
  #include <linux/string.h>
  #include <linux/socket.h>
  #include <linux/sockios.h>
  #include <linux/in.h>
  #include <linux/inet.h>
  #include <linux/netdevice.h>
  #include <linux/skbuff.h>
  #include <linux/inetdevice.h>
  #include <linux/igmp.h>
  #include <linux/if_arp.h>
  #include <linux/rtnetlink.h>
  #include <linux/times.h>

  #include <linux/pkt_sched.h>

  #include <linux/byteorder/generic.h>

  #include <net/net_namespace.h>

  #include <net/arp.h>

  #include <net/ip.h>
  #include <net/protocol.h>
  #include <net/route.h>
  #include <net/sock.h>
  #include <net/checksum.h>

  #include <net/inet_common.h>

  #include <linux/netfilter_ipv4.h>
  #ifdef CONFIG_IP_MROUTE
  #include <linux/mroute.h>
  #endif
  #ifdef CONFIG_PROC_FS
  #include <linux/proc_fs.h>
  #include <linux/seq_file.h>
  #endif

  #ifdef CONFIG_IP_MULTICAST
  /* Parameter names and values are taken from igmp-v2-06 draft */

  #define IGMP_V1_ROUTER_PRESENT_TIMEOUT		(400*HZ)
  #define IGMP_V2_ROUTER_PRESENT_TIMEOUT		(400*HZ)
  #define IGMP_V2_UNSOLICITED_REPORT_INTERVAL	(10*HZ)
  #define IGMP_V3_UNSOLICITED_REPORT_INTERVAL	(1*HZ)
  #define IGMP_QUERY_RESPONSE_INTERVAL		(10*HZ)
  #define IGMP_QUERY_ROBUSTNESS_VARIABLE		2

  #define IGMP_INITIAL_REPORT_DELAY		(1)

  /* IGMP_INITIAL_REPORT_DELAY is not from IGMP specs!

   * IGMP specs require to report membership immediately after
   * joining a group, but we delay the first report by a
   * small interval. It seems more natural and still does not
   * contradict to specs provided this delay is small enough.
   */

  #define IGMP_V1_SEEN(in_dev) \

  	(IPV4_DEVCONF_ALL(dev_net(in_dev->dev), FORCE_IGMP_VERSION) == 1 || \

  	 IN_DEV_CONF_GET((in_dev), FORCE_IGMP_VERSION) == 1 || \
  	 ((in_dev)->mr_v1_seen && \
  	  time_before(jiffies, (in_dev)->mr_v1_seen)))
  #define IGMP_V2_SEEN(in_dev) \

  	(IPV4_DEVCONF_ALL(dev_net(in_dev->dev), FORCE_IGMP_VERSION) == 2 || \

  	 IN_DEV_CONF_GET((in_dev), FORCE_IGMP_VERSION) == 2 || \
  	 ((in_dev)->mr_v2_seen && \
  	  time_before(jiffies, (in_dev)->mr_v2_seen)))

  static int unsolicited_report_interval(struct in_device *in_dev)
  {

  	int interval_ms, interval_jiffies;

  	if (IGMP_V1_SEEN(in_dev) || IGMP_V2_SEEN(in_dev))

  		interval_ms = IN_DEV_CONF_GET(
  			in_dev,
  			IGMPV2_UNSOLICITED_REPORT_INTERVAL);

  	else /* v3 */

  		interval_ms = IN_DEV_CONF_GET(
  			in_dev,
  			IGMPV3_UNSOLICITED_REPORT_INTERVAL);
  
  	interval_jiffies = msecs_to_jiffies(interval_ms);
  
  	/* _timer functions can't handle a delay of 0 jiffies so ensure
  	 *  we always return a positive value.
  	 */
  	if (interval_jiffies <= 0)
  		interval_jiffies = 1;
  	return interval_jiffies;

  }

  static void igmpv3_add_delrec(struct in_device *in_dev, struct ip_mc_list *im);

  static void igmpv3_del_delrec(struct in_device *in_dev, struct ip_mc_list *im);

  static void igmpv3_clear_delrec(struct in_device *in_dev);
  static int sf_setstate(struct ip_mc_list *pmc);
  static void sf_markstate(struct ip_mc_list *pmc);
  #endif
  static void ip_mc_clear_src(struct ip_mc_list *pmc);

  static int ip_mc_add_src(struct in_device *in_dev, __be32 *pmca, int sfmode,
  			 int sfcount, __be32 *psfsrc, int delta);

  
  static void ip_ma_put(struct ip_mc_list *im)
  {

  	if (refcount_dec_and_test(&im->refcnt)) {

  		in_dev_put(im->interface);

  		kfree_rcu(im, rcu);

  	}
  }

  #define for_each_pmc_rcu(in_dev, pmc)				\
  	for (pmc = rcu_dereference(in_dev->mc_list);		\
  	     pmc != NULL;					\
  	     pmc = rcu_dereference(pmc->next_rcu))
  
  #define for_each_pmc_rtnl(in_dev, pmc)				\
  	for (pmc = rtnl_dereference(in_dev->mc_list);		\
  	     pmc != NULL;					\
  	     pmc = rtnl_dereference(pmc->next_rcu))

  #ifdef CONFIG_IP_MULTICAST
  
  /*
   *	Timer management
   */

  static void igmp_stop_timer(struct ip_mc_list *im)

  {
  	spin_lock_bh(&im->lock);
  	if (del_timer(&im->timer))

  		refcount_dec(&im->refcnt);

  	im->tm_running = 0;

  	im->reporter = 0;
  	im->unsolicit_count = 0;
  	spin_unlock_bh(&im->lock);
  }
  
  /* It must be called with locked im->lock */
  static void igmp_start_timer(struct ip_mc_list *im, int max_delay)
  {

  	int tv = prandom_u32() % max_delay;

  	im->tm_running = 1;

  	if (!mod_timer(&im->timer, jiffies+tv+2))

  		refcount_inc(&im->refcnt);

  }
  
  static void igmp_gq_start_timer(struct in_device *in_dev)
  {

  	int tv = prandom_u32() % in_dev->mr_maxdelay;

  	unsigned long exp = jiffies + tv + 2;
  
  	if (in_dev->mr_gq_running &&
  	    time_after_eq(exp, (in_dev->mr_gq_timer).expires))
  		return;

  
  	in_dev->mr_gq_running = 1;

  	if (!mod_timer(&in_dev->mr_gq_timer, exp))

  		in_dev_hold(in_dev);
  }
  
  static void igmp_ifc_start_timer(struct in_device *in_dev, int delay)
  {

  	int tv = prandom_u32() % delay;

  
  	if (!mod_timer(&in_dev->mr_ifc_timer, jiffies+tv+2))
  		in_dev_hold(in_dev);
  }
  
  static void igmp_mod_timer(struct ip_mc_list *im, int max_delay)
  {
  	spin_lock_bh(&im->lock);
  	im->unsolicit_count = 0;
  	if (del_timer(&im->timer)) {
  		if ((long)(im->timer.expires-jiffies) < max_delay) {
  			add_timer(&im->timer);

  			im->tm_running = 1;

  			spin_unlock_bh(&im->lock);
  			return;
  		}

  		refcount_dec(&im->refcnt);

  	}
  	igmp_start_timer(im, max_delay);
  	spin_unlock_bh(&im->lock);
  }
  
  
  /*
   *	Send an IGMP report.
   */
  
  #define IGMP_SIZE (sizeof(struct igmphdr)+sizeof(struct iphdr)+4)
  
  
  static int is_in(struct ip_mc_list *pmc, struct ip_sf_list *psf, int type,
  	int gdeleted, int sdeleted)
  {
  	switch (type) {
  	case IGMPV3_MODE_IS_INCLUDE:
  	case IGMPV3_MODE_IS_EXCLUDE:
  		if (gdeleted || sdeleted)
  			return 0;

  		if (!(pmc->gsquery && !psf->sf_gsresp)) {
  			if (pmc->sfmode == MCAST_INCLUDE)
  				return 1;
  			/* don't include if this source is excluded
  			 * in all filters
  			 */
  			if (psf->sf_count[MCAST_INCLUDE])
  				return type == IGMPV3_MODE_IS_INCLUDE;
  			return pmc->sfcount[MCAST_EXCLUDE] ==
  				psf->sf_count[MCAST_EXCLUDE];
  		}
  		return 0;

  	case IGMPV3_CHANGE_TO_INCLUDE:
  		if (gdeleted || sdeleted)
  			return 0;
  		return psf->sf_count[MCAST_INCLUDE] != 0;
  	case IGMPV3_CHANGE_TO_EXCLUDE:
  		if (gdeleted || sdeleted)
  			return 0;
  		if (pmc->sfcount[MCAST_EXCLUDE] == 0 ||
  		    psf->sf_count[MCAST_INCLUDE])
  			return 0;
  		return pmc->sfcount[MCAST_EXCLUDE] ==
  			psf->sf_count[MCAST_EXCLUDE];
  	case IGMPV3_ALLOW_NEW_SOURCES:
  		if (gdeleted || !psf->sf_crcount)
  			return 0;
  		return (pmc->sfmode == MCAST_INCLUDE) ^ sdeleted;
  	case IGMPV3_BLOCK_OLD_SOURCES:
  		if (pmc->sfmode == MCAST_INCLUDE)
  			return gdeleted || (psf->sf_crcount && sdeleted);
  		return psf->sf_crcount && !gdeleted && !sdeleted;
  	}
  	return 0;
  }
  
  static int
  igmp_scount(struct ip_mc_list *pmc, int type, int gdeleted, int sdeleted)
  {
  	struct ip_sf_list *psf;
  	int scount = 0;

  	for (psf = pmc->sources; psf; psf = psf->sf_next) {

  		if (!is_in(pmc, psf, type, gdeleted, sdeleted))
  			continue;
  		scount++;
  	}
  	return scount;
  }

  /* source address selection per RFC 3376 section 4.2.13 */
  static __be32 igmpv3_get_srcaddr(struct net_device *dev,
  				 const struct flowi4 *fl4)
  {
  	struct in_device *in_dev = __in_dev_get_rcu(dev);
  
  	if (!in_dev)
  		return htonl(INADDR_ANY);
  
  	for_ifa(in_dev) {

  		if (fl4->saddr == ifa->ifa_local)

  			return fl4->saddr;
  	} endfor_ifa(in_dev);
  
  	return htonl(INADDR_ANY);
  }

  static struct sk_buff *igmpv3_newpack(struct net_device *dev, unsigned int mtu)

  {
  	struct sk_buff *skb;
  	struct rtable *rt;
  	struct iphdr *pip;
  	struct igmpv3_report *pig;

  	struct net *net = dev_net(dev);

  	struct flowi4 fl4;

  	int hlen = LL_RESERVED_SPACE(dev);
  	int tlen = dev->needed_tailroom;

  	unsigned int size = mtu;

  	while (1) {

  		skb = alloc_skb(size + hlen + tlen,

  				GFP_ATOMIC | __GFP_NOWARN);
  		if (skb)
  			break;
  		size >>= 1;
  		if (size < 256)
  			return NULL;
  	}

  	skb->priority = TC_PRIO_CONTROL;

  	rt = ip_route_output_ports(net, &fl4, NULL, IGMPV3_ALL_MCR, 0,

  				   0, 0,
  				   IPPROTO_IGMP, 0, dev->ifindex);
  	if (IS_ERR(rt)) {
  		kfree_skb(skb);
  		return NULL;

  	}

  	skb_dst_set(skb, &rt->dst);

  	skb->dev = dev;

  	skb_reserve(skb, hlen);

  	skb_tailroom_reserve(skb, mtu, tlen);

  	skb_reset_network_header(skb);

  	pip = ip_hdr(skb);

  	skb_put(skb, sizeof(struct iphdr) + 4);

  
  	pip->version  = 4;
  	pip->ihl      = (sizeof(struct iphdr)+4)>>2;
  	pip->tos      = 0xc0;
  	pip->frag_off = htons(IP_DF);
  	pip->ttl      = 1;

  	pip->daddr    = fl4.daddr;

  
  	rcu_read_lock();

  	pip->saddr    = igmpv3_get_srcaddr(dev, &fl4);

  	rcu_read_unlock();

  	pip->protocol = IPPROTO_IGMP;
  	pip->tot_len  = 0;	/* filled in later */

  	ip_select_ident(net, skb, NULL);

  	((u8 *)&pip[1])[0] = IPOPT_RA;
  	((u8 *)&pip[1])[1] = 4;
  	((u8 *)&pip[1])[2] = 0;
  	((u8 *)&pip[1])[3] = 0;

  	skb->transport_header = skb->network_header + sizeof(struct iphdr) + 4;

  	skb_put(skb, sizeof(*pig));

  	pig = igmpv3_report_hdr(skb);

  	pig->type = IGMPV3_HOST_MEMBERSHIP_REPORT;
  	pig->resv1 = 0;
  	pig->csum = 0;
  	pig->resv2 = 0;
  	pig->ngrec = 0;
  	return skb;
  }
  
  static int igmpv3_sendpack(struct sk_buff *skb)
  {

  	struct igmphdr *pig = igmp_hdr(skb);

  	const int igmplen = skb_tail_pointer(skb) - skb_transport_header(skb);

  	pig->csum = ip_compute_csum(igmp_hdr(skb), igmplen);

  	return ip_local_out(dev_net(skb_dst(skb)->dev), skb->sk, skb);

  }
  
  static int grec_size(struct ip_mc_list *pmc, int type, int gdel, int sdel)
  {

  	return sizeof(struct igmpv3_grec) + 4*igmp_scount(pmc, type, gdel, sdel);

  }
  
  static struct sk_buff *add_grhead(struct sk_buff *skb, struct ip_mc_list *pmc,

  	int type, struct igmpv3_grec **ppgr, unsigned int mtu)

  {
  	struct net_device *dev = pmc->interface->dev;
  	struct igmpv3_report *pih;
  	struct igmpv3_grec *pgr;

  	if (!skb) {
  		skb = igmpv3_newpack(dev, mtu);
  		if (!skb)
  			return NULL;
  	}

  	pgr = skb_put(skb, sizeof(struct igmpv3_grec));

  	pgr->grec_type = type;
  	pgr->grec_auxwords = 0;
  	pgr->grec_nsrcs = 0;
  	pgr->grec_mca = pmc->multiaddr;

  	pih = igmpv3_report_hdr(skb);

  	pih->ngrec = htons(ntohs(pih->ngrec)+1);
  	*ppgr = pgr;
  	return skb;
  }

  #define AVAILABLE(skb)	((skb) ? skb_availroom(skb) : 0)

  
  static struct sk_buff *add_grec(struct sk_buff *skb, struct ip_mc_list *pmc,
  	int type, int gdeleted, int sdeleted)
  {
  	struct net_device *dev = pmc->interface->dev;

  	struct net *net = dev_net(dev);

  	struct igmpv3_report *pih;
  	struct igmpv3_grec *pgr = NULL;
  	struct ip_sf_list *psf, *psf_next, *psf_prev, **psf_list;

  	int scount, stotal, first, isquery, truncate;

  	unsigned int mtu;

  
  	if (pmc->multiaddr == IGMP_ALL_HOSTS)
  		return skb;

  	if (ipv4_is_local_multicast(pmc->multiaddr) && !net->ipv4.sysctl_igmp_llm_reports)

  		return skb;

  	mtu = READ_ONCE(dev->mtu);
  	if (mtu < IPV4_MIN_MTU)
  		return skb;

  	isquery = type == IGMPV3_MODE_IS_INCLUDE ||
  		  type == IGMPV3_MODE_IS_EXCLUDE;
  	truncate = type == IGMPV3_MODE_IS_EXCLUDE ||
  		    type == IGMPV3_CHANGE_TO_EXCLUDE;

  	stotal = scount = 0;

  	psf_list = sdeleted ? &pmc->tomb : &pmc->sources;

  	if (!*psf_list)
  		goto empty_source;

  	pih = skb ? igmpv3_report_hdr(skb) : NULL;

  
  	/* EX and TO_EX get a fresh packet, if needed */
  	if (truncate) {
  		if (pih && pih->ngrec &&
  		    AVAILABLE(skb) < grec_size(pmc, type, gdeleted, sdeleted)) {
  			if (skb)
  				igmpv3_sendpack(skb);

  			skb = igmpv3_newpack(dev, mtu);

  		}
  	}
  	first = 1;

  	psf_prev = NULL;

  	for (psf = *psf_list; psf; psf = psf_next) {

  		__be32 *psrc;

  
  		psf_next = psf->sf_next;
  
  		if (!is_in(pmc, psf, type, gdeleted, sdeleted)) {
  			psf_prev = psf;
  			continue;
  		}

  		/* Based on RFC3376 5.1. Should not send source-list change
  		 * records when there is a filter mode change.
  		 */
  		if (((gdeleted && pmc->sfmode == MCAST_EXCLUDE) ||
  		     (!gdeleted && pmc->crcount)) &&
  		    (type == IGMPV3_ALLOW_NEW_SOURCES ||
  		     type == IGMPV3_BLOCK_OLD_SOURCES) && psf->sf_crcount)
  			goto decrease_sf_crcount;

  		/* clear marks on query responses */
  		if (isquery)
  			psf->sf_gsresp = 0;

  		if (AVAILABLE(skb) < sizeof(__be32) +

  		    first*sizeof(struct igmpv3_grec)) {
  			if (truncate && !first)
  				break;	 /* truncate these */
  			if (pgr)
  				pgr->grec_nsrcs = htons(scount);
  			if (skb)
  				igmpv3_sendpack(skb);

  			skb = igmpv3_newpack(dev, mtu);

  			first = 1;
  			scount = 0;
  		}
  		if (first) {

  			skb = add_grhead(skb, pmc, type, &pgr, mtu);

  			first = 0;
  		}

  		if (!skb)
  			return NULL;

  		psrc = skb_put(skb, sizeof(__be32));

  		*psrc = psf->sf_inaddr;

  		scount++; stotal++;

  		if ((type == IGMPV3_ALLOW_NEW_SOURCES ||
  		     type == IGMPV3_BLOCK_OLD_SOURCES) && psf->sf_crcount) {

  decrease_sf_crcount:

  			psf->sf_crcount--;
  			if ((sdeleted || gdeleted) && psf->sf_crcount == 0) {
  				if (psf_prev)
  					psf_prev->sf_next = psf->sf_next;
  				else
  					*psf_list = psf->sf_next;
  				kfree(psf);
  				continue;
  			}
  		}
  		psf_prev = psf;
  	}

  
  empty_source:
  	if (!stotal) {
  		if (type == IGMPV3_ALLOW_NEW_SOURCES ||
  		    type == IGMPV3_BLOCK_OLD_SOURCES)
  			return skb;
  		if (pmc->crcount || isquery) {
  			/* make sure we have room for group header */

  			if (skb && AVAILABLE(skb) < sizeof(struct igmpv3_grec)) {

  				igmpv3_sendpack(skb);
  				skb = NULL; /* add_grhead will get a new one */
  			}

  			skb = add_grhead(skb, pmc, type, &pgr, mtu);

  		}
  	}

  	if (pgr)
  		pgr->grec_nsrcs = htons(scount);
  
  	if (isquery)
  		pmc->gsquery = 0;	/* clear query state on report */
  	return skb;
  }
  
  static int igmpv3_send_report(struct in_device *in_dev, struct ip_mc_list *pmc)
  {
  	struct sk_buff *skb = NULL;

  	struct net *net = dev_net(in_dev->dev);

  	int type;
  
  	if (!pmc) {

  		rcu_read_lock();
  		for_each_pmc_rcu(in_dev, pmc) {

  			if (pmc->multiaddr == IGMP_ALL_HOSTS)
  				continue;

  			if (ipv4_is_local_multicast(pmc->multiaddr) &&

  			     !net->ipv4.sysctl_igmp_llm_reports)

  				continue;

  			spin_lock_bh(&pmc->lock);
  			if (pmc->sfcount[MCAST_EXCLUDE])
  				type = IGMPV3_MODE_IS_EXCLUDE;
  			else
  				type = IGMPV3_MODE_IS_INCLUDE;
  			skb = add_grec(skb, pmc, type, 0, 0);
  			spin_unlock_bh(&pmc->lock);
  		}

  		rcu_read_unlock();

  	} else {
  		spin_lock_bh(&pmc->lock);
  		if (pmc->sfcount[MCAST_EXCLUDE])
  			type = IGMPV3_MODE_IS_EXCLUDE;
  		else
  			type = IGMPV3_MODE_IS_INCLUDE;
  		skb = add_grec(skb, pmc, type, 0, 0);
  		spin_unlock_bh(&pmc->lock);
  	}
  	if (!skb)
  		return 0;
  	return igmpv3_sendpack(skb);
  }
  
  /*
   * remove zero-count source records from a source filter list
   */
  static void igmpv3_clear_zeros(struct ip_sf_list **ppsf)
  {
  	struct ip_sf_list *psf_prev, *psf_next, *psf;
  
  	psf_prev = NULL;

  	for (psf = *ppsf; psf; psf = psf_next) {

  		psf_next = psf->sf_next;
  		if (psf->sf_crcount == 0) {
  			if (psf_prev)
  				psf_prev->sf_next = psf->sf_next;
  			else
  				*ppsf = psf->sf_next;
  			kfree(psf);
  		} else
  			psf_prev = psf;
  	}
  }
  
  static void igmpv3_send_cr(struct in_device *in_dev)
  {
  	struct ip_mc_list *pmc, *pmc_prev, *pmc_next;
  	struct sk_buff *skb = NULL;
  	int type, dtype;

  	rcu_read_lock();

  	spin_lock_bh(&in_dev->mc_tomb_lock);
  
  	/* deleted MCA's */
  	pmc_prev = NULL;

  	for (pmc = in_dev->mc_tomb; pmc; pmc = pmc_next) {

  		pmc_next = pmc->next;
  		if (pmc->sfmode == MCAST_INCLUDE) {
  			type = IGMPV3_BLOCK_OLD_SOURCES;
  			dtype = IGMPV3_BLOCK_OLD_SOURCES;
  			skb = add_grec(skb, pmc, type, 1, 0);
  			skb = add_grec(skb, pmc, dtype, 1, 1);
  		}
  		if (pmc->crcount) {

  			if (pmc->sfmode == MCAST_EXCLUDE) {
  				type = IGMPV3_CHANGE_TO_INCLUDE;
  				skb = add_grec(skb, pmc, type, 1, 0);
  			}

  			pmc->crcount--;

  			if (pmc->crcount == 0) {
  				igmpv3_clear_zeros(&pmc->tomb);
  				igmpv3_clear_zeros(&pmc->sources);
  			}
  		}
  		if (pmc->crcount == 0 && !pmc->tomb && !pmc->sources) {
  			if (pmc_prev)
  				pmc_prev->next = pmc_next;
  			else
  				in_dev->mc_tomb = pmc_next;
  			in_dev_put(pmc->interface);
  			kfree(pmc);
  		} else
  			pmc_prev = pmc;
  	}
  	spin_unlock_bh(&in_dev->mc_tomb_lock);
  
  	/* change recs */

  	for_each_pmc_rcu(in_dev, pmc) {

  		spin_lock_bh(&pmc->lock);
  		if (pmc->sfcount[MCAST_EXCLUDE]) {
  			type = IGMPV3_BLOCK_OLD_SOURCES;
  			dtype = IGMPV3_ALLOW_NEW_SOURCES;
  		} else {
  			type = IGMPV3_ALLOW_NEW_SOURCES;
  			dtype = IGMPV3_BLOCK_OLD_SOURCES;
  		}
  		skb = add_grec(skb, pmc, type, 0, 0);
  		skb = add_grec(skb, pmc, dtype, 0, 1);	/* deleted sources */
  
  		/* filter mode changes */
  		if (pmc->crcount) {

  			if (pmc->sfmode == MCAST_EXCLUDE)
  				type = IGMPV3_CHANGE_TO_EXCLUDE;
  			else
  				type = IGMPV3_CHANGE_TO_INCLUDE;
  			skb = add_grec(skb, pmc, type, 0, 0);

  			pmc->crcount--;

  		}
  		spin_unlock_bh(&pmc->lock);
  	}

  	rcu_read_unlock();

  
  	if (!skb)
  		return;
  	(void) igmpv3_sendpack(skb);
  }
  
  static int igmp_send_report(struct in_device *in_dev, struct ip_mc_list *pmc,
  	int type)
  {
  	struct sk_buff *skb;
  	struct iphdr *iph;
  	struct igmphdr *ih;
  	struct rtable *rt;
  	struct net_device *dev = in_dev->dev;

  	struct net *net = dev_net(dev);

  	__be32	group = pmc ? pmc->multiaddr : 0;

  	struct flowi4 fl4;

  	__be32	dst;

  	int hlen, tlen;

  
  	if (type == IGMPV3_HOST_MEMBERSHIP_REPORT)
  		return igmpv3_send_report(in_dev, pmc);

  	if (ipv4_is_local_multicast(group) && !net->ipv4.sysctl_igmp_llm_reports)

  		return 0;
  
  	if (type == IGMP_HOST_LEAVE_MESSAGE)

  		dst = IGMP_ALL_ROUTER;
  	else
  		dst = group;

  	rt = ip_route_output_ports(net, &fl4, NULL, dst, 0,

  				   0, 0,
  				   IPPROTO_IGMP, 0, dev->ifindex);
  	if (IS_ERR(rt))
  		return -1;

  	hlen = LL_RESERVED_SPACE(dev);
  	tlen = dev->needed_tailroom;
  	skb = alloc_skb(IGMP_SIZE + hlen + tlen, GFP_ATOMIC);

  	if (!skb) {

  		ip_rt_put(rt);
  		return -1;
  	}

  	skb->priority = TC_PRIO_CONTROL;

  	skb_dst_set(skb, &rt->dst);

  	skb_reserve(skb, hlen);

  	skb_reset_network_header(skb);

  	iph = ip_hdr(skb);

  	skb_put(skb, sizeof(struct iphdr) + 4);

  
  	iph->version  = 4;
  	iph->ihl      = (sizeof(struct iphdr)+4)>>2;
  	iph->tos      = 0xc0;
  	iph->frag_off = htons(IP_DF);
  	iph->ttl      = 1;
  	iph->daddr    = dst;

  	iph->saddr    = fl4.saddr;

  	iph->protocol = IPPROTO_IGMP;

  	ip_select_ident(net, skb, NULL);

  	((u8 *)&iph[1])[0] = IPOPT_RA;
  	((u8 *)&iph[1])[1] = 4;
  	((u8 *)&iph[1])[2] = 0;
  	((u8 *)&iph[1])[3] = 0;

  	ih = skb_put(skb, sizeof(struct igmphdr));

  	ih->type = type;
  	ih->code = 0;
  	ih->csum = 0;
  	ih->group = group;
  	ih->csum = ip_compute_csum((void *)ih, sizeof(struct igmphdr));

  	return ip_local_out(net, skb->sk, skb);

  }
  
  static void igmp_gq_timer_expire(unsigned long data)
  {
  	struct in_device *in_dev = (struct in_device *)data;
  
  	in_dev->mr_gq_running = 0;
  	igmpv3_send_report(in_dev, NULL);

  	in_dev_put(in_dev);

  }
  
  static void igmp_ifc_timer_expire(unsigned long data)
  {
  	struct in_device *in_dev = (struct in_device *)data;
  
  	igmpv3_send_cr(in_dev);
  	if (in_dev->mr_ifc_count) {
  		in_dev->mr_ifc_count--;

  		igmp_ifc_start_timer(in_dev,
  				     unsolicited_report_interval(in_dev));

  	}

  	in_dev_put(in_dev);

  }
  
  static void igmp_ifc_event(struct in_device *in_dev)
  {

  	struct net *net = dev_net(in_dev->dev);

  	if (IGMP_V1_SEEN(in_dev) || IGMP_V2_SEEN(in_dev))
  		return;

  	in_dev->mr_ifc_count = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;

  	igmp_ifc_start_timer(in_dev, 1);
  }
  
  
  static void igmp_timer_expire(unsigned long data)
  {

  	struct ip_mc_list *im = (struct ip_mc_list *)data;

  	struct in_device *in_dev = im->interface;
  
  	spin_lock(&im->lock);

  	im->tm_running = 0;

  
  	if (im->unsolicit_count) {
  		im->unsolicit_count--;

  		igmp_start_timer(im, unsolicited_report_interval(in_dev));

  	}
  	im->reporter = 1;
  	spin_unlock(&im->lock);
  
  	if (IGMP_V1_SEEN(in_dev))
  		igmp_send_report(in_dev, im, IGMP_HOST_MEMBERSHIP_REPORT);
  	else if (IGMP_V2_SEEN(in_dev))
  		igmp_send_report(in_dev, im, IGMPV2_HOST_MEMBERSHIP_REPORT);
  	else
  		igmp_send_report(in_dev, im, IGMPV3_HOST_MEMBERSHIP_REPORT);
  
  	ip_ma_put(im);
  }

  /* mark EXCLUDE-mode sources */

  static int igmp_xmarksources(struct ip_mc_list *pmc, int nsrcs, __be32 *srcs)

  {
  	struct ip_sf_list *psf;
  	int i, scount;
  
  	scount = 0;

  	for (psf = pmc->sources; psf; psf = psf->sf_next) {

  		if (scount == nsrcs)
  			break;

  		for (i = 0; i < nsrcs; i++) {

  			/* skip inactive filters */

  			if (psf->sf_count[MCAST_INCLUDE] ||

  			    pmc->sfcount[MCAST_EXCLUDE] !=
  			    psf->sf_count[MCAST_EXCLUDE])

  				break;

  			if (srcs[i] == psf->sf_inaddr) {
  				scount++;
  				break;
  			}
  		}
  	}
  	pmc->gsquery = 0;
  	if (scount == nsrcs)	/* all sources excluded */
  		return 0;
  	return 1;
  }

  static int igmp_marksources(struct ip_mc_list *pmc, int nsrcs, __be32 *srcs)

  {
  	struct ip_sf_list *psf;
  	int i, scount;
  
  	if (pmc->sfmode == MCAST_EXCLUDE)
  		return igmp_xmarksources(pmc, nsrcs, srcs);
  
  	/* mark INCLUDE-mode sources */
  	scount = 0;

  	for (psf = pmc->sources; psf; psf = psf->sf_next) {

  		if (scount == nsrcs)
  			break;

  		for (i = 0; i < nsrcs; i++)

  			if (srcs[i] == psf->sf_inaddr) {
  				psf->sf_gsresp = 1;
  				scount++;
  				break;
  			}
  	}

  	if (!scount) {
  		pmc->gsquery = 0;
  		return 0;
  	}
  	pmc->gsquery = 1;
  	return 1;

  }

  /* return true if packet was dropped */
  static bool igmp_heard_report(struct in_device *in_dev, __be32 group)

  {
  	struct ip_mc_list *im;

  	struct net *net = dev_net(in_dev->dev);

  
  	/* Timers are only set for non-local groups */
  
  	if (group == IGMP_ALL_HOSTS)

  		return false;

  	if (ipv4_is_local_multicast(group) && !net->ipv4.sysctl_igmp_llm_reports)

  		return false;

  	rcu_read_lock();
  	for_each_pmc_rcu(in_dev, im) {

  		if (im->multiaddr == group) {
  			igmp_stop_timer(im);
  			break;
  		}
  	}

  	rcu_read_unlock();

  	return false;

  }

  /* return true if packet was dropped */
  static bool igmp_heard_query(struct in_device *in_dev, struct sk_buff *skb,

  	int len)
  {

  	struct igmphdr 		*ih = igmp_hdr(skb);
  	struct igmpv3_query *ih3 = igmpv3_query_hdr(skb);

  	struct ip_mc_list	*im;

  	__be32			group = ih->group;

  	int			max_delay;
  	int			mark = 0;

  	struct net		*net = dev_net(in_dev->dev);

  	if (len == 8) {

  		if (ih->code == 0) {
  			/* Alas, old v1 router presents here. */

  			max_delay = IGMP_QUERY_RESPONSE_INTERVAL;

  			in_dev->mr_v1_seen = jiffies +

  				IGMP_V1_ROUTER_PRESENT_TIMEOUT;

  			group = 0;
  		} else {
  			/* v2 router present */
  			max_delay = ih->code*(HZ/IGMP_TIMER_SCALE);
  			in_dev->mr_v2_seen = jiffies +

  				IGMP_V2_ROUTER_PRESENT_TIMEOUT;

  		}
  		/* cancel the interface change timer */
  		in_dev->mr_ifc_count = 0;
  		if (del_timer(&in_dev->mr_ifc_timer))
  			__in_dev_put(in_dev);
  		/* clear deleted report items */
  		igmpv3_clear_delrec(in_dev);
  	} else if (len < 12) {

  		return true;	/* ignore bogus packet; freed by caller */

  	} else if (IGMP_V1_SEEN(in_dev)) {
  		/* This is a v3 query with v1 queriers present */

  		max_delay = IGMP_QUERY_RESPONSE_INTERVAL;

  		group = 0;
  	} else if (IGMP_V2_SEEN(in_dev)) {
  		/* this is a v3 query with v2 queriers present;
  		 * Interpretation of the max_delay code is problematic here.
  		 * A real v2 host would use ih_code directly, while v3 has a
  		 * different encoding. We use the v3 encoding as more likely
  		 * to be intended in a v3 query.
  		 */
  		max_delay = IGMPV3_MRC(ih3->code)*(HZ/IGMP_TIMER_SCALE);

  		if (!max_delay)
  			max_delay = 1;	/* can't mod w/ 0 */

  	} else { /* v3 */
  		if (!pskb_may_pull(skb, sizeof(struct igmpv3_query)))

  			return true;

  		ih3 = igmpv3_query_hdr(skb);

  		if (ih3->nsrcs) {

  			if (!pskb_may_pull(skb, sizeof(struct igmpv3_query)

  					   + ntohs(ih3->nsrcs)*sizeof(__be32)))

  				return true;

  			ih3 = igmpv3_query_hdr(skb);

  		}
  
  		max_delay = IGMPV3_MRC(ih3->code)*(HZ/IGMP_TIMER_SCALE);
  		if (!max_delay)
  			max_delay = 1;	/* can't mod w/ 0 */
  		in_dev->mr_maxdelay = max_delay;
  		if (ih3->qrv)
  			in_dev->mr_qrv = ih3->qrv;
  		if (!group) { /* general query */
  			if (ih3->nsrcs)

  				return true;	/* no sources allowed */

  			igmp_gq_start_timer(in_dev);

  			return false;

  		}
  		/* mark sources to include, if group & source-specific */
  		mark = ih3->nsrcs != 0;
  	}
  
  	/*
  	 * - Start the timers in all of our membership records
  	 *   that the query applies to for the interface on
  	 *   which the query arrived excl. those that belong
  	 *   to a "local" group (224.0.0.X)
  	 * - For timers already running check if they need to
  	 *   be reset.
  	 * - Use the igmp->igmp_code field as the maximum
  	 *   delay possible
  	 */

  	rcu_read_lock();
  	for_each_pmc_rcu(in_dev, im) {

  		int changed;

  		if (group && group != im->multiaddr)
  			continue;
  		if (im->multiaddr == IGMP_ALL_HOSTS)
  			continue;

  		if (ipv4_is_local_multicast(im->multiaddr) &&

  		    !net->ipv4.sysctl_igmp_llm_reports)

  			continue;

  		spin_lock_bh(&im->lock);
  		if (im->tm_running)
  			im->gsquery = im->gsquery && mark;
  		else
  			im->gsquery = mark;

  		changed = !im->gsquery ||

  			igmp_marksources(im, ntohs(ih3->nsrcs), ih3->srcs);

  		spin_unlock_bh(&im->lock);

  		if (changed)
  			igmp_mod_timer(im, max_delay);

  	}

  	rcu_read_unlock();

  	return false;

  }

  /* called in rcu_read_lock() section */

  int igmp_rcv(struct sk_buff *skb)
  {
  	/* This basically follows the spec line by line -- see RFC1112 */
  	struct igmphdr *ih;

  	struct net_device *dev = skb->dev;
  	struct in_device *in_dev;

  	int len = skb->len;

  	bool dropped = true;

  	if (netif_is_l3_master(dev)) {
  		dev = dev_get_by_index_rcu(dev_net(dev), IPCB(skb)->iif);
  		if (!dev)
  			goto drop;
  	}
  
  	in_dev = __in_dev_get_rcu(dev);

  	if (!in_dev)

  		goto drop;

  	if (!pskb_may_pull(skb, sizeof(struct igmphdr)))

  		goto drop;

  	if (skb_checksum_simple_validate(skb))
  		goto drop;

  	ih = igmp_hdr(skb);

  	switch (ih->type) {
  	case IGMP_HOST_MEMBERSHIP_QUERY:

  		dropped = igmp_heard_query(in_dev, skb, len);

  		break;
  	case IGMP_HOST_MEMBERSHIP_REPORT:
  	case IGMPV2_HOST_MEMBERSHIP_REPORT:

  		/* Is it our report looped back? */

  		if (rt_is_output_route(skb_rtable(skb)))

  			break;

  		/* don't rely on MC router hearing unicast reports */
  		if (skb->pkt_type == PACKET_MULTICAST ||
  		    skb->pkt_type == PACKET_BROADCAST)

  			dropped = igmp_heard_report(in_dev, ih->group);

  		break;
  	case IGMP_PIM:
  #ifdef CONFIG_IP_PIMSM_V1

  		return pim_rcv_v1(skb);
  #endif

  	case IGMPV3_HOST_MEMBERSHIP_REPORT:

  	case IGMP_DVMRP:
  	case IGMP_TRACE:
  	case IGMP_HOST_LEAVE_MESSAGE:
  	case IGMP_MTRACE:
  	case IGMP_MTRACE_RESP:
  		break;
  	default:

  		break;

  	}

  drop:

  	if (dropped)
  		kfree_skb(skb);
  	else
  		consume_skb(skb);

  	return 0;
  }
  
  #endif
  
  
  /*
   *	Add a filter to a device
   */

  static void ip_mc_filter_add(struct in_device *in_dev, __be32 addr)

  {
  	char buf[MAX_ADDR_LEN];
  	struct net_device *dev = in_dev->dev;
  
  	/* Checking for IFF_MULTICAST here is WRONG-WRONG-WRONG.
  	   We will get multicast token leakage, when IFF_MULTICAST

  	   is changed. This check should be done in ndo_set_rx_mode

  	   routine. Something sort of:
  	   if (dev->mc_list && dev->flags&IFF_MULTICAST) { do it; }
  	   --ANK
  	   */
  	if (arp_mc_map(addr, buf, dev, 0) == 0)

  		dev_mc_add(dev, buf);

  }
  
  /*
   *	Remove a filter from a device
   */

  static void ip_mc_filter_del(struct in_device *in_dev, __be32 addr)

  {
  	char buf[MAX_ADDR_LEN];
  	struct net_device *dev = in_dev->dev;
  
  	if (arp_mc_map(addr, buf, dev, 0) == 0)

  		dev_mc_del(dev, buf);

  }
  
  #ifdef CONFIG_IP_MULTICAST
  /*
   * deleted ip_mc_list manipulation
   */
  static void igmpv3_add_delrec(struct in_device *in_dev, struct ip_mc_list *im)
  {
  	struct ip_mc_list *pmc;

  	struct net *net = dev_net(in_dev->dev);

  
  	/* this is an "ip_mc_list" for convenience; only the fields below
  	 * are actually used. In particular, the refcnt and users are not
  	 * used for management of the delete list. Using the same structure
  	 * for deleted items allows change reports to use common code with
  	 * non-deleted or query-response MCA's.
  	 */

  	pmc = kzalloc(sizeof(*pmc), GFP_KERNEL);

  	if (!pmc)
  		return;

  	spin_lock_init(&pmc->lock);

  	spin_lock_bh(&im->lock);
  	pmc->interface = im->interface;
  	in_dev_hold(in_dev);
  	pmc->multiaddr = im->multiaddr;

  	pmc->crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;

  	pmc->sfmode = im->sfmode;
  	if (pmc->sfmode == MCAST_INCLUDE) {
  		struct ip_sf_list *psf;
  
  		pmc->tomb = im->tomb;
  		pmc->sources = im->sources;
  		im->tomb = im->sources = NULL;

  		for (psf = pmc->sources; psf; psf = psf->sf_next)

  			psf->sf_crcount = pmc->crcount;
  	}
  	spin_unlock_bh(&im->lock);
  
  	spin_lock_bh(&in_dev->mc_tomb_lock);
  	pmc->next = in_dev->mc_tomb;
  	in_dev->mc_tomb = pmc;
  	spin_unlock_bh(&in_dev->mc_tomb_lock);
  }

  /*
   * restore ip_mc_list deleted records
   */
  static void igmpv3_del_delrec(struct in_device *in_dev, struct ip_mc_list *im)

  {
  	struct ip_mc_list *pmc, *pmc_prev;

  	struct ip_sf_list *psf;
  	struct net *net = dev_net(in_dev->dev);
  	__be32 multiaddr = im->multiaddr;

  
  	spin_lock_bh(&in_dev->mc_tomb_lock);
  	pmc_prev = NULL;

  	for (pmc = in_dev->mc_tomb; pmc; pmc = pmc->next) {

  		if (pmc->multiaddr == multiaddr)
  			break;
  		pmc_prev = pmc;
  	}
  	if (pmc) {
  		if (pmc_prev)
  			pmc_prev->next = pmc->next;
  		else
  			in_dev->mc_tomb = pmc->next;
  	}
  	spin_unlock_bh(&in_dev->mc_tomb_lock);

  
  	spin_lock_bh(&im->lock);

  	if (pmc) {

  		im->interface = pmc->interface;
  		im->crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;

  		if (im->sfmode == MCAST_INCLUDE) {

  			im->tomb = pmc->tomb;
  			im->sources = pmc->sources;
  			for (psf = im->sources; psf; psf = psf->sf_next)
  				psf->sf_crcount = im->crcount;

  		}
  		in_dev_put(pmc->interface);

  		kfree(pmc);

  	}

  	spin_unlock_bh(&im->lock);

  }

  /*
   * flush ip_mc_list deleted records
   */

  static void igmpv3_clear_delrec(struct in_device *in_dev)
  {
  	struct ip_mc_list *pmc, *nextpmc;
  
  	spin_lock_bh(&in_dev->mc_tomb_lock);
  	pmc = in_dev->mc_tomb;
  	in_dev->mc_tomb = NULL;
  	spin_unlock_bh(&in_dev->mc_tomb_lock);
  
  	for (; pmc; pmc = nextpmc) {
  		nextpmc = pmc->next;
  		ip_mc_clear_src(pmc);
  		in_dev_put(pmc->interface);
  		kfree(pmc);
  	}
  	/* clear dead sources, too */

  	rcu_read_lock();
  	for_each_pmc_rcu(in_dev, pmc) {

  		struct ip_sf_list *psf, *psf_next;
  
  		spin_lock_bh(&pmc->lock);
  		psf = pmc->tomb;
  		pmc->tomb = NULL;
  		spin_unlock_bh(&pmc->lock);

  		for (; psf; psf = psf_next) {

  			psf_next = psf->sf_next;
  			kfree(psf);
  		}
  	}

  	rcu_read_unlock();

  }
  #endif
  
  static void igmp_group_dropped(struct ip_mc_list *im)
  {
  	struct in_device *in_dev = im->interface;
  #ifdef CONFIG_IP_MULTICAST

  	struct net *net = dev_net(in_dev->dev);

  	int reporter;
  #endif
  
  	if (im->loaded) {
  		im->loaded = 0;
  		ip_mc_filter_del(in_dev, im->multiaddr);
  	}
  
  #ifdef CONFIG_IP_MULTICAST
  	if (im->multiaddr == IGMP_ALL_HOSTS)
  		return;

  	if (ipv4_is_local_multicast(im->multiaddr) && !net->ipv4.sysctl_igmp_llm_reports)

  		return;

  
  	reporter = im->reporter;
  	igmp_stop_timer(im);
  
  	if (!in_dev->dead) {
  		if (IGMP_V1_SEEN(in_dev))

  			return;

  		if (IGMP_V2_SEEN(in_dev)) {
  			if (reporter)
  				igmp_send_report(in_dev, im, IGMP_HOST_LEAVE_MESSAGE);

  			return;

  		}
  		/* IGMPv3 */
  		igmpv3_add_delrec(in_dev, im);
  
  		igmp_ifc_event(in_dev);
  	}

  #endif

  }
  
  static void igmp_group_added(struct ip_mc_list *im)
  {
  	struct in_device *in_dev = im->interface;

  #ifdef CONFIG_IP_MULTICAST

  	struct net *net = dev_net(in_dev->dev);

  #endif

  
  	if (im->loaded == 0) {
  		im->loaded = 1;
  		ip_mc_filter_add(in_dev, im->multiaddr);
  	}
  
  #ifdef CONFIG_IP_MULTICAST
  	if (im->multiaddr == IGMP_ALL_HOSTS)
  		return;

  	if (ipv4_is_local_multicast(im->multiaddr) && !net->ipv4.sysctl_igmp_llm_reports)

  		return;

  
  	if (in_dev->dead)
  		return;
  	if (IGMP_V1_SEEN(in_dev) || IGMP_V2_SEEN(in_dev)) {
  		spin_lock_bh(&im->lock);

  		igmp_start_timer(im, IGMP_INITIAL_REPORT_DELAY);

  		spin_unlock_bh(&im->lock);
  		return;
  	}
  	/* else, v3 */

  	im->crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;

  	igmp_ifc_event(in_dev);
  #endif
  }
  
  
  /*
   *	Multicast list managers
   */

  static u32 ip_mc_hash(const struct ip_mc_list *im)
  {

  	return hash_32((__force u32)im->multiaddr, MC_HASH_SZ_LOG);

  }
  
  static void ip_mc_hash_add(struct in_device *in_dev,
  			   struct ip_mc_list *im)
  {
  	struct ip_mc_list __rcu **mc_hash;
  	u32 hash;
  
  	mc_hash = rtnl_dereference(in_dev->mc_hash);
  	if (mc_hash) {
  		hash = ip_mc_hash(im);

  		im->next_hash = mc_hash[hash];

  		rcu_assign_pointer(mc_hash[hash], im);
  		return;
  	}
  
  	/* do not use a hash table for small number of items */
  	if (in_dev->mc_count < 4)
  		return;
  
  	mc_hash = kzalloc(sizeof(struct ip_mc_list *) << MC_HASH_SZ_LOG,
  			  GFP_KERNEL);
  	if (!mc_hash)
  		return;
  
  	for_each_pmc_rtnl(in_dev, im) {
  		hash = ip_mc_hash(im);

  		im->next_hash = mc_hash[hash];

  		RCU_INIT_POINTER(mc_hash[hash], im);
  	}
  
  	rcu_assign_pointer(in_dev->mc_hash, mc_hash);
  }
  
  static void ip_mc_hash_remove(struct in_device *in_dev,
  			      struct ip_mc_list *im)
  {
  	struct ip_mc_list __rcu **mc_hash = rtnl_dereference(in_dev->mc_hash);
  	struct ip_mc_list *aux;
  
  	if (!mc_hash)
  		return;
  	mc_hash += ip_mc_hash(im);
  	while ((aux = rtnl_dereference(*mc_hash)) != im)
  		mc_hash = &aux->next_hash;
  	*mc_hash = im->next_hash;
  }

  
  /*
   *	A socket has joined a multicast group on device dev.
   */

  void ip_mc_inc_group(struct in_device *in_dev, __be32 addr)

  {
  	struct ip_mc_list *im;

  #ifdef CONFIG_IP_MULTICAST

  	struct net *net = dev_net(in_dev->dev);

  #endif

  
  	ASSERT_RTNL();

  	for_each_pmc_rtnl(in_dev, im) {

  		if (im->multiaddr == addr) {
  			im->users++;
  			ip_mc_add_src(in_dev, &addr, MCAST_EXCLUDE, 0, NULL, 0);
  			goto out;
  		}
  	}

  	im = kzalloc(sizeof(*im), GFP_KERNEL);

  	if (!im)
  		goto out;

  	im->users = 1;
  	im->interface = in_dev;

  	in_dev_hold(in_dev);

  	im->multiaddr = addr;

  	/* initial mode is (EX, empty) */
  	im->sfmode = MCAST_EXCLUDE;

  	im->sfcount[MCAST_EXCLUDE] = 1;

  	refcount_set(&im->refcnt, 1);

  	spin_lock_init(&im->lock);
  #ifdef CONFIG_IP_MULTICAST

  	setup_timer(&im->timer, igmp_timer_expire, (unsigned long)im);

  	im->unsolicit_count = net->ipv4.sysctl_igmp_qrv;

  #endif

  
  	im->next_rcu = in_dev->mc_list;

  	in_dev->mc_count++;

  	rcu_assign_pointer(in_dev->mc_list, im);

  	ip_mc_hash_add(in_dev, im);

  #ifdef CONFIG_IP_MULTICAST

  	igmpv3_del_delrec(in_dev, im);

  #endif
  	igmp_group_added(im);
  	if (!in_dev->dead)
  		ip_rt_multicast_event(in_dev);
  out:
  	return;
  }

  EXPORT_SYMBOL(ip_mc_inc_group);

  static int ip_mc_check_iphdr(struct sk_buff *skb)
  {
  	const struct iphdr *iph;
  	unsigned int len;
  	unsigned int offset = skb_network_offset(skb) + sizeof(*iph);
  
  	if (!pskb_may_pull(skb, offset))
  		return -EINVAL;
  
  	iph = ip_hdr(skb);
  
  	if (iph->version != 4 || ip_hdrlen(skb) < sizeof(*iph))
  		return -EINVAL;
  
  	offset += ip_hdrlen(skb) - sizeof(*iph);
  
  	if (!pskb_may_pull(skb, offset))
  		return -EINVAL;
  
  	iph = ip_hdr(skb);
  
  	if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
  		return -EINVAL;
  
  	len = skb_network_offset(skb) + ntohs(iph->tot_len);
  	if (skb->len < len || len < offset)
  		return -EINVAL;
  
  	skb_set_transport_header(skb, offset);
  
  	return 0;
  }
  
  static int ip_mc_check_igmp_reportv3(struct sk_buff *skb)
  {
  	unsigned int len = skb_transport_offset(skb);
  
  	len += sizeof(struct igmpv3_report);
  
  	return pskb_may_pull(skb, len) ? 0 : -EINVAL;
  }
  
  static int ip_mc_check_igmp_query(struct sk_buff *skb)
  {
  	unsigned int len = skb_transport_offset(skb);
  
  	len += sizeof(struct igmphdr);
  	if (skb->len < len)
  		return -EINVAL;
  
  	/* IGMPv{1,2}? */
  	if (skb->len != len) {
  		/* or IGMPv3? */
  		len += sizeof(struct igmpv3_query) - sizeof(struct igmphdr);
  		if (skb->len < len || !pskb_may_pull(skb, len))
  			return -EINVAL;
  	}
  
  	/* RFC2236+RFC3376 (IGMPv2+IGMPv3) require the multicast link layer
  	 * all-systems destination addresses (224.0.0.1) for general queries
  	 */
  	if (!igmp_hdr(skb)->group &&
  	    ip_hdr(skb)->daddr != htonl(INADDR_ALLHOSTS_GROUP))
  		return -EINVAL;
  
  	return 0;
  }
  
  static int ip_mc_check_igmp_msg(struct sk_buff *skb)
  {
  	switch (igmp_hdr(skb)->type) {
  	case IGMP_HOST_LEAVE_MESSAGE:
  	case IGMP_HOST_MEMBERSHIP_REPORT:
  	case IGMPV2_HOST_MEMBERSHIP_REPORT:
  		/* fall through */
  		return 0;
  	case IGMPV3_HOST_MEMBERSHIP_REPORT:
  		return ip_mc_check_igmp_reportv3(skb);
  	case IGMP_HOST_MEMBERSHIP_QUERY:
  		return ip_mc_check_igmp_query(skb);
  	default:
  		return -ENOMSG;
  	}
  }
  
  static inline __sum16 ip_mc_validate_checksum(struct sk_buff *skb)
  {
  	return skb_checksum_simple_validate(skb);
  }
  
  static int __ip_mc_check_igmp(struct sk_buff *skb, struct sk_buff **skb_trimmed)
  
  {
  	struct sk_buff *skb_chk;
  	unsigned int transport_len;
  	unsigned int len = skb_transport_offset(skb) + sizeof(struct igmphdr);

  	int ret = -EINVAL;

  
  	transport_len = ntohs(ip_hdr(skb)->tot_len) - ip_hdrlen(skb);

  	skb_chk = skb_checksum_trimmed(skb, transport_len,
  				       ip_mc_validate_checksum);
  	if (!skb_chk)

  		goto err;

  	if (!pskb_may_pull(skb_chk, len))
  		goto err;

  
  	ret = ip_mc_check_igmp_msg(skb_chk);

  	if (ret)
  		goto err;

  
  	if (skb_trimmed)
  		*skb_trimmed = skb_chk;

  	/* free now unneeded clone */
  	else if (skb_chk != skb)

  		kfree_skb(skb_chk);

  	ret = 0;
  
  err:
  	if (ret && skb_chk && skb_chk != skb)
  		kfree_skb(skb_chk);
  
  	return ret;

  }
  
  /**
   * ip_mc_check_igmp - checks whether this is a sane IGMP packet
   * @skb: the skb to validate
   * @skb_trimmed: to store an skb pointer trimmed to IPv4 packet tail (optional)
   *
   * Checks whether an IPv4 packet is a valid IGMP packet. If so sets

   * skb transport header accordingly and returns zero.

   *
   * -EINVAL: A broken packet was detected, i.e. it violates some internet
   *  standard
   * -ENOMSG: IP header validation succeeded but it is not an IGMP packet.
   * -ENOMEM: A memory allocation failure happened.
   *
   * Optionally, an skb pointer might be provided via skb_trimmed (or set it
   * to NULL): After parsing an IGMP packet successfully it will point to
   * an skb which has its tail aligned to the IP packet end. This might
   * either be the originally provided skb or a trimmed, cloned version if
   * the skb frame had data beyond the IP packet. A cloned skb allows us
   * to leave the original skb and its full frame unchanged (which might be
   * desirable for layer 2 frame jugglers).
   *

   * Caller needs to set the skb network header and free any returned skb if it
   * differs from the provided skb.

   */
  int ip_mc_check_igmp(struct sk_buff *skb, struct sk_buff **skb_trimmed)
  {
  	int ret = ip_mc_check_iphdr(skb);
  
  	if (ret < 0)
  		return ret;
  
  	if (ip_hdr(skb)->protocol != IPPROTO_IGMP)
  		return -ENOMSG;
  
  	return __ip_mc_check_igmp(skb, skb_trimmed);
  }
  EXPORT_SYMBOL(ip_mc_check_igmp);

  /*

   *	Resend IGMP JOIN report; used by netdev notifier.

   */

  static void ip_mc_rejoin_groups(struct in_device *in_dev)

  {

  #ifdef CONFIG_IP_MULTICAST

  	struct ip_mc_list *im;
  	int type;

  	struct net *net = dev_net(in_dev->dev);

  	ASSERT_RTNL();
  
  	for_each_pmc_rtnl(in_dev, im) {

  		if (im->multiaddr == IGMP_ALL_HOSTS)
  			continue;

  		if (ipv4_is_local_multicast(im->multiaddr) &&

  		    !net->ipv4.sysctl_igmp_llm_reports)

  			continue;

  		/* a failover is happening and switches
  		 * must be notified immediately
  		 */
  		if (IGMP_V1_SEEN(in_dev))
  			type = IGMP_HOST_MEMBERSHIP_REPORT;
  		else if (IGMP_V2_SEEN(in_dev))
  			type = IGMPV2_HOST_MEMBERSHIP_REPORT;
  		else
  			type = IGMPV3_HOST_MEMBERSHIP_REPORT;
  		igmp_send_report(in_dev, im, type);
  	}

  #endif
  }
  
  /*

   *	A socket has left a multicast group on device dev
   */

  void ip_mc_dec_group(struct in_device *in_dev, __be32 addr)

  {

  	struct ip_mc_list *i;
  	struct ip_mc_list __rcu **ip;

  	ASSERT_RTNL();

  	for (ip = &in_dev->mc_list;
  	     (i = rtnl_dereference(*ip)) != NULL;
  	     ip = &i->next_rcu) {

  		if (i->multiaddr == addr) {

  			if (--i->users == 0) {

  				ip_mc_hash_remove(in_dev, i);

  				*ip = i->next_rcu;

  				in_dev->mc_count--;

  				igmp_group_dropped(i);

  				ip_mc_clear_src(i);

  
  				if (!in_dev->dead)
  					ip_rt_multicast_event(in_dev);
  
  				ip_ma_put(i);
  				return;
  			}
  			break;
  		}
  	}
  }

  EXPORT_SYMBOL(ip_mc_dec_group);

  /* Device changing type */
  
  void ip_mc_unmap(struct in_device *in_dev)
  {

  	struct ip_mc_list *pmc;

  
  	ASSERT_RTNL();

  	for_each_pmc_rtnl(in_dev, pmc)
  		igmp_group_dropped(pmc);

  }
  
  void ip_mc_remap(struct in_device *in_dev)
  {

  	struct ip_mc_list *pmc;

  
  	ASSERT_RTNL();

  	for_each_pmc_rtnl(in_dev, pmc) {
  #ifdef CONFIG_IP_MULTICAST
  		igmpv3_del_delrec(in_dev, pmc);
  #endif

  		igmp_group_added(pmc);

  	}

  }

  /* Device going down */
  
  void ip_mc_down(struct in_device *in_dev)
  {

  	struct ip_mc_list *pmc;

  
  	ASSERT_RTNL();

  	for_each_pmc_rtnl(in_dev, pmc)
  		igmp_group_dropped(pmc);

  
  #ifdef CONFIG_IP_MULTICAST
  	in_dev->mr_ifc_count = 0;
  	if (del_timer(&in_dev->mr_ifc_timer))
  		__in_dev_put(in_dev);
  	in_dev->mr_gq_running = 0;
  	if (del_timer(&in_dev->mr_gq_timer))
  		__in_dev_put(in_dev);

  #endif
  
  	ip_mc_dec_group(in_dev, IGMP_ALL_HOSTS);
  }
  
  void ip_mc_init_dev(struct in_device *in_dev)
  {

  #ifdef CONFIG_IP_MULTICAST

  	struct net *net = dev_net(in_dev->dev);

  #endif

  	ASSERT_RTNL();

  #ifdef CONFIG_IP_MULTICAST

  	setup_timer(&in_dev->mr_gq_timer, igmp_gq_timer_expire,
  			(unsigned long)in_dev);

  	setup_timer(&in_dev->mr_ifc_timer, igmp_ifc_timer_expire,
  			(unsigned long)in_dev);

  	in_dev->mr_qrv = net->ipv4.sysctl_igmp_qrv;

  #endif

  	spin_lock_init(&in_dev->mc_tomb_lock);
  }
  
  /* Device going up */
  
  void ip_mc_up(struct in_device *in_dev)
  {

  	struct ip_mc_list *pmc;

  #ifdef CONFIG_IP_MULTICAST

  	struct net *net = dev_net(in_dev->dev);

  #endif

  
  	ASSERT_RTNL();

  #ifdef CONFIG_IP_MULTICAST

  	in_dev->mr_qrv = net->ipv4.sysctl_igmp_qrv;

  #endif

  	ip_mc_inc_group(in_dev, IGMP_ALL_HOSTS);

  	for_each_pmc_rtnl(in_dev, pmc) {
  #ifdef CONFIG_IP_MULTICAST
  		igmpv3_del_delrec(in_dev, pmc);
  #endif

  		igmp_group_added(pmc);

  	}

  }
  
  /*
   *	Device is about to be destroyed: clean up.
   */
  
  void ip_mc_destroy_dev(struct in_device *in_dev)
  {
  	struct ip_mc_list *i;
  
  	ASSERT_RTNL();
  
  	/* Deactivate timers */
  	ip_mc_down(in_dev);

  #ifdef CONFIG_IP_MULTICAST
  	igmpv3_clear_delrec(in_dev);
  #endif

  	while ((i = rtnl_dereference(in_dev->mc_list)) != NULL) {
  		in_dev->mc_list = i->next_rcu;

  		in_dev->mc_count--;

  		ip_ma_put(i);

  	}

  }

  /* RTNL is locked */

  static struct in_device *ip_mc_find_dev(struct net *net, struct ip_mreqn *imr)

  {

  	struct net_device *dev = NULL;
  	struct in_device *idev = NULL;
  
  	if (imr->imr_ifindex) {

  		idev = inetdev_by_index(net, imr->imr_ifindex);

  		return idev;
  	}
  	if (imr->imr_address.s_addr) {

  		dev = __ip_dev_find(net, imr->imr_address.s_addr, false);

  		if (!dev)
  			return NULL;

  	}

  	if (!dev) {

  		struct rtable *rt = ip_route_output(net,
  						    imr->imr_multiaddr.s_addr,
  						    0, 0, 0);

  		if (!IS_ERR(rt)) {
  			dev = rt->dst.dev;
  			ip_rt_put(rt);
  		}

  	}
  	if (dev) {
  		imr->imr_ifindex = dev->ifindex;

  		idev = __in_dev_get_rtnl(dev);

  	}
  	return idev;
  }
  
  /*
   *	Join a socket to a group
   */

  
  static int ip_mc_del1_src(struct ip_mc_list *pmc, int sfmode,

  	__be32 *psfsrc)

  {
  	struct ip_sf_list *psf, *psf_prev;
  	int rv = 0;
  
  	psf_prev = NULL;

  	for (psf = pmc->sources; psf; psf = psf->sf_next) {

  		if (psf->sf_inaddr == *psfsrc)
  			break;
  		psf_prev = psf;
  	}
  	if (!psf || psf->sf_count[sfmode] == 0) {
  		/* source filter not found, or count wrong =>  bug */
  		return -ESRCH;
  	}
  	psf->sf_count[sfmode]--;
  	if (psf->sf_count[sfmode] == 0) {
  		ip_rt_multicast_event(pmc->interface);
  	}
  	if (!psf->sf_count[MCAST_INCLUDE] && !psf->sf_count[MCAST_EXCLUDE]) {
  #ifdef CONFIG_IP_MULTICAST
  		struct in_device *in_dev = pmc->interface;

  		struct net *net = dev_net(in_dev->dev);

  #endif
  
  		/* no more filters for this source */
  		if (psf_prev)
  			psf_prev->sf_next = psf->sf_next;
  		else
  			pmc->sources = psf->sf_next;
  #ifdef CONFIG_IP_MULTICAST
  		if (psf->sf_oldin &&
  		    !IGMP_V1_SEEN(in_dev) && !IGMP_V2_SEEN(in_dev)) {

  			psf->sf_crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;

  			psf->sf_next = pmc->tomb;
  			pmc->tomb = psf;
  			rv = 1;
  		} else
  #endif
  			kfree(psf);
  	}
  	return rv;
  }
  
  #ifndef CONFIG_IP_MULTICAST
  #define igmp_ifc_event(x)	do { } while (0)
  #endif

  static int ip_mc_del_src(struct in_device *in_dev, __be32 *pmca, int sfmode,
  			 int sfcount, __be32 *psfsrc, int delta)

  {
  	struct ip_mc_list *pmc;
  	int	changerec = 0;
  	int	i, err;
  
  	if (!in_dev)
  		return -ENODEV;

  	rcu_read_lock();
  	for_each_pmc_rcu(in_dev, pmc) {

  		if (*pmca == pmc->multiaddr)
  			break;
  	}
  	if (!pmc) {
  		/* MCA not found?? bug */

  		rcu_read_unlock();

  		return -ESRCH;
  	}
  	spin_lock_bh(&pmc->lock);

  	rcu_read_unlock();

  #ifdef CONFIG_IP_MULTICAST
  	sf_markstate(pmc);
  #endif
  	if (!delta) {
  		err = -EINVAL;
  		if (!pmc->sfcount[sfmode])
  			goto out_unlock;
  		pmc->sfcount[sfmode]--;
  	}
  	err = 0;

  	for (i = 0; i < sfcount; i++) {

  		int rv = ip_mc_del1_src(pmc, sfmode, &psfsrc[i]);
  
  		changerec |= rv > 0;
  		if (!err && rv < 0)
  			err = rv;
  	}
  	if (pmc->sfmode == MCAST_EXCLUDE &&
  	    pmc->sfcount[MCAST_EXCLUDE] == 0 &&
  	    pmc->sfcount[MCAST_INCLUDE]) {
  #ifdef CONFIG_IP_MULTICAST
  		struct ip_sf_list *psf;

  		struct net *net = dev_net(in_dev->dev);

  #endif
  
  		/* filter mode change */
  		pmc->sfmode = MCAST_INCLUDE;
  #ifdef CONFIG_IP_MULTICAST

  		pmc->crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;

  		in_dev->mr_ifc_count = pmc->crcount;

  		for (psf = pmc->sources; psf; psf = psf->sf_next)

  			psf->sf_crcount = 0;
  		igmp_ifc_event(pmc->interface);
  	} else if (sf_setstate(pmc) || changerec) {
  		igmp_ifc_event(pmc->interface);
  #endif
  	}
  out_unlock:
  	spin_unlock_bh(&pmc->lock);
  	return err;
  }
  
  /*
   * Add multicast single-source filter to the interface list
   */
  static int ip_mc_add1_src(struct ip_mc_list *pmc, int sfmode,

  	__be32 *psfsrc)

  {
  	struct ip_sf_list *psf, *psf_prev;
  
  	psf_prev = NULL;

  	for (psf = pmc->sources; psf; psf = psf->sf_next) {

  		if (psf->sf_inaddr == *psfsrc)
  			break;
  		psf_prev = psf;
  	}
  	if (!psf) {

  		psf = kzalloc(sizeof(*psf), GFP_ATOMIC);

  		if (!psf)
  			return -ENOBUFS;

  		psf->sf_inaddr = *psfsrc;
  		if (psf_prev) {
  			psf_prev->sf_next = psf;
  		} else
  			pmc->sources = psf;
  	}
  	psf->sf_count[sfmode]++;
  	if (psf->sf_count[sfmode] == 1) {
  		ip_rt_multicast_event(pmc->interface);
  	}
  	return 0;
  }
  
  #ifdef CONFIG_IP_MULTICAST
  static void sf_markstate(struct ip_mc_list *pmc)
  {
  	struct ip_sf_list *psf;
  	int mca_xcount = pmc->sfcount[MCAST_EXCLUDE];

  	for (psf = pmc->sources; psf; psf = psf->sf_next)

  		if (pmc->sfcount[MCAST_EXCLUDE]) {
  			psf->sf_oldin = mca_xcount ==
  				psf->sf_count[MCAST_EXCLUDE] &&
  				!psf->sf_count[MCAST_INCLUDE];
  		} else
  			psf->sf_oldin = psf->sf_count[MCAST_INCLUDE] != 0;
  }
  
  static int sf_setstate(struct ip_mc_list *pmc)
  {

  	struct ip_sf_list *psf, *dpsf;

  	int mca_xcount = pmc->sfcount[MCAST_EXCLUDE];
  	int qrv = pmc->interface->mr_qrv;
  	int new_in, rv;
  
  	rv = 0;

  	for (psf = pmc->sources; psf; psf = psf->sf_next) {

  		if (pmc->sfcount[MCAST_EXCLUDE]) {
  			new_in = mca_xcount == psf->sf_count[MCAST_EXCLUDE] &&
  				!psf->sf_count[MCAST_INCLUDE];
  		} else
  			new_in = psf->sf_count[MCAST_INCLUDE] != 0;

  		if (new_in) {
  			if (!psf->sf_oldin) {

  				struct ip_sf_list *prev = NULL;

  				for (dpsf = pmc->tomb; dpsf; dpsf = dpsf->sf_next) {

  					if (dpsf->sf_inaddr == psf->sf_inaddr)
  						break;
  					prev = dpsf;
  				}
  				if (dpsf) {
  					if (prev)
  						prev->sf_next = dpsf->sf_next;
  					else
  						pmc->tomb = dpsf->sf_next;
  					kfree(dpsf);
  				}
  				psf->sf_crcount = qrv;
  				rv++;
  			}
  		} else if (psf->sf_oldin) {
  
  			psf->sf_crcount = 0;
  			/*
  			 * add or update "delete" records if an active filter
  			 * is now inactive
  			 */

  			for (dpsf = pmc->tomb; dpsf; dpsf = dpsf->sf_next)

  				if (dpsf->sf_inaddr == psf->sf_inaddr)
  					break;
  			if (!dpsf) {

  				dpsf = kmalloc(sizeof(*dpsf), GFP_ATOMIC);

  				if (!dpsf)
  					continue;
  				*dpsf = *psf;
  				/* pmc->lock held by callers */
  				dpsf->sf_next = pmc->tomb;
  				pmc->tomb = dpsf;
  			}
  			dpsf->sf_crcount = qrv;

  			rv++;
  		}
  	}
  	return rv;
  }
  #endif
  
  /*
   * Add multicast source filter list to the interface list
   */

  static int ip_mc_add_src(struct in_device *in_dev, __be32 *pmca, int sfmode,
  			 int sfcount, __be32 *psfsrc, int delta)

  {
  	struct ip_mc_list *pmc;
  	int	isexclude;
  	int	i, err;
  
  	if (!in_dev)
  		return -ENODEV;

  	rcu_read_lock();
  	for_each_pmc_rcu(in_dev, pmc) {

  		if (*pmca == pmc->multiaddr)
  			break;
  	}
  	if (!pmc) {
  		/* MCA not found?? bug */

  		rcu_read_unlock();

  		return -ESRCH;
  	}
  	spin_lock_bh(&pmc->lock);

  	rcu_read_unlock();

  
  #ifdef CONFIG_IP_MULTICAST
  	sf_markstate(pmc);
  #endif
  	isexclude = pmc->sfmode == MCAST_EXCLUDE;
  	if (!delta)
  		pmc->sfcount[sfmode]++;
  	err = 0;

  	for (i = 0; i < sfcount; i++) {

  		err = ip_mc_add1_src(pmc, sfmode, &psfsrc[i]);

  		if (err)
  			break;
  	}
  	if (err) {
  		int j;

  		if (!delta)
  			pmc->sfcount[sfmode]--;

  		for (j = 0; j < i; j++)

  			(void) ip_mc_del1_src(pmc, sfmode, &psfsrc[j]);

  	} else if (isexclude != (pmc->sfcount[MCAST_EXCLUDE] != 0)) {
  #ifdef CONFIG_IP_MULTICAST

  		struct ip_sf_list *psf;

  		struct net *net = dev_net(pmc->interface->dev);

  		in_dev = pmc->interface;

  #endif
  
  		/* filter mode change */
  		if (pmc->sfcount[MCAST_EXCLUDE])
  			pmc->sfmode = MCAST_EXCLUDE;
  		else if (pmc->sfcount[MCAST_INCLUDE])
  			pmc->sfmode = MCAST_INCLUDE;
  #ifdef CONFIG_IP_MULTICAST
  		/* else no filters; keep old mode for reports */

  		pmc->crcount = in_dev->mr_qrv ?: net->ipv4.sysctl_igmp_qrv;

  		in_dev->mr_ifc_count = pmc->crcount;

  		for (psf = pmc->sources; psf; psf = psf->sf_next)

  			psf->sf_crcount = 0;
  		igmp_ifc_event(in_dev);
  	} else if (sf_setstate(pmc)) {
  		igmp_ifc_event(in_dev);
  #endif
  	}
  	spin_unlock_bh(&pmc->lock);
  	return err;
  }
  
  static void ip_mc_clear_src(struct ip_mc_list *pmc)
  {