text: /*
   *	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\n"
   *					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 <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 (atomic_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))
  		atomic_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))
  		atomic_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;
  		}
  		atomic_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;
  }
  
  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;
  	pip->saddr    = fl4.saddr;
  	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)
  {
  	struct net_device *dev = pmc->interface->dev;
  	struct igmpv3_report *pih;
  	struct igmpv3_grec *pgr;
  
  	if (!skb)
  		skb = igmpv3_newpack(dev, dev->mtu);
  	if (!skb)
  		return NULL;
  	pgr = (struct igmpv3_grec *)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;
  
  	if (pmc->multiaddr == IGMP_ALL_HOSTS)
  		return skb;
  	if (ipv4_is_local_multicast(pmc->multiaddr) && !net->ipv4.sysctl_igmp_llm_reports)
  		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, 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, dev->mtu);
  			first = 1;
  			scount = 0;
  		}
  		if (first) {
  			skb = add_grhead(skb, pmc, type, &pgr);
  			first = 0;
  		}
  		if (!skb)
  			return NULL;
  		psrc = (__be32 *)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);
  		}
  	}
  	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 = (struct igmphdr *)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 in_device *in_dev = __in_dev_get_rcu(skb->dev);
  	int len = skb->len;
  	bool dropped = true;
  
  	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_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;
  		im->sfmode = pmc->sfmode;
  		if (pmc->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;
  	atomic_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)
  {
  	struct ip_sf_list *psf, *nextpsf;
  
  	for (psf = pmc->tomb; psf; psf = nextpsf) {
  		nextpsf = psf->sf_next;
  		kfree(psf);
  	}
  	pmc->tomb = NULL;
  	for (psf = pmc->sources; psf; psf = nextpsf) {
  		nextpsf = psf->sf_next;
  		kfree(psf);
  	}
  	pmc->sources = NULL;
  	pmc->sfmode = MCAST_EXCLUDE;
  	pmc->sfcount[MCAST_INCLUDE] = 0;
  	pmc->sfcount[MCAST_EXCLUDE] = 1;
  }
  
  /* Join a multicast group
   */
  
  int ip_mc_join_group(struct sock *sk, struct ip_mreqn *imr)
  {
  	__be32 addr = imr->imr_multiaddr.s_addr;
  	struct ip_mc_socklist *iml, *i;
  	struct in_device *in_dev;
  	struct inet_sock *inet = inet_sk(sk);
  	struct net *net = sock_net(sk);
  	int ifindex;
  	int count = 0;
  	int err;
  
  	ASSERT_RTNL();
  
  	if (!ipv4_is_multicast(addr))
  		return -EINVAL;
  
  	in_dev = ip_mc_find_dev(net, imr);
  
  	if (!in_dev) {
  		err = -ENODEV;
  		goto done;
  	}
  
  	err = -EADDRINUSE;
  	ifindex = imr->imr_ifindex;
  	for_each_pmc_rtnl(inet, i) {
  		if (i->multi.imr_multiaddr.s_addr == addr &&
  		    i->multi.imr_ifindex == ifindex)
  			goto done;
  		count++;
  	}
  	err = -ENOBUFS;
  	if (count >= net->ipv4.sysctl_igmp_max_memberships)
  		goto done;
  	iml = sock_kmalloc(sk, sizeof(*iml), GFP_KERNEL);
  	if (!iml)
  		goto done;
  
  	memcpy(&iml->multi, imr, sizeof(*imr));
  	iml->next_rcu = inet->mc_list;
  	iml->sflist = NULL;
  	iml->sfmode = MCAST_EXCLUDE;
  	rcu_assign_pointer(inet->mc_list, iml);
  	ip_mc_inc_group(in_dev, addr);
  	err = 0;
  done:
  	return err;
  }
  EXPORT_SYMBOL(ip_mc_join_group);
  
  static int ip_mc_leave_src(struct sock *sk, struct ip_mc_socklist *iml,
  			   struct in_device *in_dev)
  {
  	struct ip_sf_socklist *psf = rtnl_dereference(iml->sflist);
  	int err;
  
  	if (!psf) {
  		/* any-source empty exclude case */
  		return ip_mc_del_src(in_dev, &iml->multi.imr_multiaddr.s_addr,
  			iml->sfmode, 0, NULL, 0);
  	}
  	err = ip_mc_del_src(in_dev, &iml->multi.imr_multiaddr.s_addr,
  			iml->sfmode, psf->sl_count, psf->sl_addr, 0);
  	RCU_INIT_POINTER(iml->sflist, NULL);
  	/* decrease mem now to avoid the memleak warning */
  	atomic_sub(IP_SFLSIZE(psf->sl_max), &sk->sk_omem_alloc);
  	kfree_rcu(psf, rcu);
  	return err;
  }
  
  int ip_mc_leave_group(struct sock *sk, struct ip_mreqn *imr)
  {
  	struct inet_sock *inet = inet_sk(sk);
  	struct ip_mc_socklist *iml;
  	struct ip_mc_socklist __rcu **imlp;
  	struct in_device *in_dev;
  	struct net *net = sock_net(sk);
  	__be32 group = imr->imr_multiaddr.s_addr;
  	u32 ifindex;
  	int ret = -EADDRNOTAVAIL;
  
  	ASSERT_RTNL();
  
  	in_dev = ip_mc_find_dev(net, imr);
  	if (!imr->imr_ifindex && !imr->imr_address.s_addr && !in_dev) {
  		ret = -ENODEV;
  		goto out;
  	}
  	ifindex = imr->imr_ifindex;
  	for (imlp = &inet->mc_list;
  	     (iml = rtnl_dereference(*imlp)) != NULL;
  	     imlp = &iml->next_rcu) {
  		if (iml->multi.imr_multiaddr.s_addr != group)
  			continue;
  		if (ifindex) {
  			if (iml->multi.imr_ifindex != ifindex)
  				continue;
  		} else if (imr->imr_address.s_addr && imr->imr_address.s_addr !=
  				iml->multi.imr_address.s_addr)
  			continue;
  
  		(void) ip_mc_leave_src(sk, iml, in_dev);
  
  		*imlp = iml->next_rcu;
  
  		if (in_dev)
  			ip_mc_dec_group(in_dev, group);
  
  		/* decrease mem now to avoid the memleak warning */
  		atomic_sub(sizeof(*iml), &sk->sk_omem_alloc);
  		kfree_rcu(iml, rcu);
  		return 0;
  	}
  out:
  	return ret;
  }
  EXPORT_SYMBOL(ip_mc_leave_group);
  
  int ip_mc_source(int add, int omode, struct sock *sk, struct
  	ip_mreq_source *mreqs, int ifindex)
  {
  	int err;
  	struct ip_mreqn imr;
  	__be32 addr = mreqs->imr_multiaddr;
  	struct ip_mc_socklist *pmc;
  	struct in_device *in_dev = NULL;
  	struct inet_sock *inet = inet_sk(sk);
  	struct ip_sf_socklist *psl;
  	struct net *net = sock_net(sk);
  	int leavegroup = 0;
  	int i, j, rv;
  
  	if (!ipv4_is_multicast(addr))
  		return -EINVAL;
  
  	ASSERT_RTNL();
  
  	imr.imr_multiaddr.s_addr = mreqs->imr_multiaddr;
  	imr.imr_address.s_addr = mreqs->imr_interface;
  	imr.imr_ifindex = ifindex;
  	in_dev = ip_mc_find_dev(net, &imr);
  
  	if (!in_dev) {
  		err = -ENODEV;
  		goto done;
  	}
  	err = -EADDRNOTAVAIL;
  
  	for_each_pmc_rtnl(inet, pmc) {
  		if ((pmc->multi.imr_multiaddr.s_addr ==
  		     imr.imr_multiaddr.s_addr) &&
  		    (pmc->multi.imr_ifindex == imr.imr_ifindex))
  			break;
  	}
  	if (!pmc) {		/* must have a prior join */
  		err = -EINVAL;
  		goto done;
  	}
  	/* if a source filter was set, must be the same mode as before */
  	if (pmc->sflist) {
  		if (pmc->sfmode != omode) {
  			err = -EINVAL;
  			goto done;
  		}
  	} else if (pmc->sfmode != omode) {
  		/* allow mode switches for empty-set filters */
  		ip_mc_add_src(in_dev, &mreqs->imr_multiaddr, omode, 0, NULL, 0);
  		ip_mc_del_src(in_dev, &mreqs->imr_multiaddr, pmc->sfmode, 0,
  			NULL, 0);
  		pmc->sfmode = omode;
  	}
  
  	psl = rtnl_dereference(pmc->sflist);
  	if (!add) {
  		if (!psl)
  			goto done;	/* err = -EADDRNOTAVAIL */
  		rv = !0;
  		for (i = 0; i < psl->sl_count; i++) {
  			rv = memcmp(&psl->sl_addr[i], &mreqs->imr_sourceaddr,
  				sizeof(__be32));
  			if (rv == 0)
  				break;
  		}
  		if (rv)		/* source not found */
  			goto done;	/* err = -EADDRNOTAVAIL */
  
  		/* special case - (INCLUDE, empty) == LEAVE_GROUP */
  		if (psl->sl_count == 1 && omode == MCAST_INCLUDE) {
  			leavegroup = 1;
  			goto done;
  		}
  
  		/* update the interface filter */
  		ip_mc_del_src(in_dev, &mreqs->imr_multiaddr, omode, 1,
  			&mreqs->imr_sourceaddr, 1);
  
  		for (j = i+1; j < psl->sl_count; j++)
  			psl->sl_addr[j-1] = psl->sl_addr[j];
  		psl->sl_count--;
  		err = 0;
  		goto done;
  	}
  	/* else, add a new source to the filter */
  
  	if (psl && psl->sl_count >= net->ipv4.sysctl_igmp_max_msf) {
  		err = -ENOBUFS;
  		goto done;
  	}
  	if (!psl || psl->sl_count == psl->sl_max) {
  		struct ip_sf_socklist *newpsl;
  		int count = IP_SFBLOCK;
  
  		if (psl)
  			count += psl->sl_max;
  		newpsl = sock_kmalloc(sk, IP_SFLSIZE(count), GFP_KERNEL);
  		if (!newpsl) {
  			err = -ENOBUFS;
  			goto done;
  		}
  		newpsl->sl_max = count;
  		newpsl->sl_count = count - IP_SFBLOCK;
  		if (psl) {
  			for (i = 0; i < psl->sl_count; i++)
  				newpsl->sl_addr[i] = psl->sl_addr[i];
  			/* decrease mem now to avoid the memleak warning */
  			atomic_sub(IP_SFLSIZE(psl->sl_max), &sk->sk_omem_alloc);
  			kfree_rcu(psl, rcu);
  		}
  		rcu_assign_pointer(pmc->sflist, newpsl);
  		psl = newpsl;
  	}
  	rv = 1;	/* > 0 for insert logic below if sl_count is 0 */
  	for (i = 0; i < psl->sl_count; i++) {
  		rv = memcmp(&psl->sl_addr[i], &mreqs->imr_sourceaddr,
  			sizeof(__be32));
  		if (rv == 0)
  			break;
  	}
  	if (rv == 0)		/* address already there is an error */
  		goto done;
  	for (j = psl->sl_count-1; j >= i; j--)
  		psl->sl_addr[j+1] = psl->sl_addr[j];
  	psl->sl_addr[i] = mreqs->imr_sourceaddr;
  	psl->sl_count++;
  	err = 0;
  	/* update the interface list */
  	ip_mc_add_src(in_dev, &mreqs->imr_multiaddr, omode, 1,
  		&mreqs->imr_sourceaddr, 1);
  done:
  	if (leavegroup)
  		err = ip_mc_leave_group(sk, &imr);
  	return err;
  }
  
  int ip_mc_msfilter(struct sock *sk, struct ip_msfilter *msf, int ifindex)
  {
  	int err = 0;
  	struct ip_mreqn	imr;
  	__be32 addr = msf->imsf_multiaddr;
  	struct ip_mc_socklist *pmc;
  	struct in_device *in_dev;
  	struct inet_sock *inet = inet_sk(sk);
  	struct ip_sf_socklist *newpsl, *psl;
  	struct net *net = sock_net(sk);
  	int leavegroup = 0;
  
  	if (!ipv4_is_multicast(addr))
  		return -EINVAL;
  	if (msf->imsf_fmode != MCAST_INCLUDE &&
  	    msf->imsf_fmode != MCAST_EXCLUDE)
  		return -EINVAL;
  
  	ASSERT_RTNL();
  
  	imr.imr_multiaddr.s_addr = msf->imsf_multiaddr;
  	imr.imr_address.s_addr = msf->imsf_interface;
  	imr.imr_ifindex = ifindex;
  	in_dev = ip_mc_find_dev(net, &imr);
  
  	if (!in_dev) {
  		err = -ENODEV;
  		goto done;
  	}
  
  	/* special case - (INCLUDE, empty) == LEAVE_GROUP */
  	if (msf->imsf_fmode == MCAST_INCLUDE && msf->imsf_numsrc == 0) {
  		leavegroup = 1;
  		goto done;
  	}
  
  	for_each_pmc_rtnl(inet, pmc) {
  		if (pmc->multi.imr_multiaddr.s_addr == msf->imsf_multiaddr &&
  		    pmc->multi.imr_ifindex == imr.imr_ifindex)
  			break;
  	}
  	if (!pmc) {		/* must have a prior join */
  		err = -EINVAL;
  		goto done;
  	}
  	if (msf->imsf_numsrc) {
  		newpsl = sock_kmalloc(sk, IP_SFLSIZE(msf->imsf_numsrc),
  							   GFP_KERNEL);
  		if (!newpsl) {
  			err = -ENOBUFS;
  			goto done;
  		}
  		newpsl->sl_max = newpsl->sl_count = msf->imsf_numsrc;
  		memcpy(newpsl->sl_addr, msf->imsf_slist,
  			msf->imsf_numsrc * sizeof(msf->imsf_slist[0]));
  		err = ip_mc_add_src(in_dev, &msf->imsf_multiaddr,
  			msf->imsf_fmode, newpsl->sl_count, newpsl->sl_addr, 0);
  		if (err) {
  			sock_kfree_s(sk, newpsl, IP_SFLSIZE(newpsl->sl_max));
  			goto done;
  		}
  	} else {
  		newpsl = NULL;
  		(void) ip_mc_add_src(in_dev, &msf->imsf_multiaddr,
  				     msf->imsf_fmode, 0, NULL, 0);
  	}
  	psl = rtnl_dereference(pmc->sflist);
  	if (psl) {
  		(void) ip_mc_del_src(in_dev, &msf->imsf_multiaddr, pmc->sfmode,
  			psl->sl_count, psl->sl_addr, 0);
  		/* decrease mem now to avoid the memleak warning */
  		atomic_sub(IP_SFLSIZE(psl->sl_max), &sk->sk_omem_alloc);
  		kfree_rcu(psl, rcu);
  	} else
  		(void) ip_mc_del_src(in_dev, &msf->imsf_multiaddr, pmc->sfmode,
  			0, NULL, 0);
  	rcu_assign_pointer(pmc->sflist, newpsl);
  	pmc->sfmode = msf->imsf_fmode;
  	err = 0;
  done:
  	if (leavegroup)
  		err = ip_mc_leave_group(sk, &imr);
  	return err;
  }
  
  int ip_mc_msfget(struct sock *sk, struct ip_msfilter *msf,
  	struct ip_msfilter __user *optval, int __user *optlen)
  {
  	int err, len, count, copycount;
  	struct ip_mreqn	imr;
  	__be32 addr = msf->imsf_multiaddr;
  	struct ip_mc_socklist *pmc;
  	struct in_device *in_dev;
  	struct inet_sock *inet = inet_sk(sk);
  	struct ip_sf_socklist *psl;
  	struct net *net = sock_net(sk);
  
  	ASSERT_RTNL();
  
  	if (!ipv4_is_multicast(addr))
  		return -EINVAL;
  
  	imr.imr_multiaddr.s_addr = msf->imsf_multiaddr;
  	imr.imr_address.s_addr = msf->imsf_interface;
  	imr.imr_ifindex = 0;
  	in_dev = ip_mc_find_dev(net, &imr);
  
  	if (!in_dev) {
  		err = -ENODEV;
  		goto done;
  	}
  	err = -EADDRNOTAVAIL;
  
  	for_each_pmc_rtnl(inet, pmc) {
  		if (pmc->multi.imr_multiaddr.s_addr == msf->imsf_multiaddr &&
  		    pmc->multi.imr_ifindex == imr.imr_ifindex)
  			break;
  	}
  	if (!pmc)		/* must have a prior join */
  		goto done;
  	msf->imsf_fmode = pmc->sfmode;
  	psl = rtnl_dereference(pmc->sflist);
  	if (!psl) {
  		len = 0;
  		count = 0;
  	} else {
  		count = psl->sl_count;
  	}
  	copycount = count < msf->imsf_numsrc ? count : msf->imsf_numsrc;
  	len = copycount * sizeof(psl->sl_addr[0]);
  	msf->imsf_numsrc = count;
  	if (put_user(IP_MSFILTER_SIZE(copycount), optlen) ||
  	    copy_to_user(optval, msf, IP_MSFILTER_SIZE(0))) {
  		return -EFAULT;
  	}
  	if (len &&
  	    copy_to_user(&optval->imsf_slist[0], psl->sl_addr, len))
  		return -EFAULT;
  	return 0;
  done:
  	return err;
  }
  
  int ip_mc_gsfget(struct sock *sk, struct group_filter *gsf,
  	struct group_filter __user *optval, int __user *optlen)
  {
  	int err, i, count, copycount;
  	struct sockaddr_in *psin;
  	__be32 addr;
  	struct ip_mc_socklist *pmc;
  	struct inet_sock *inet = inet_sk(sk);
  	struct ip_sf_socklist *psl;
  
  	ASSERT_RTNL();
  
  	psin = (struct sockaddr_in *)&gsf->gf_group;
  	if (psin->sin_family != AF_INET)
  		return -EINVAL;
  	addr = psin->sin_addr.s_addr;
  	if (!ipv4_is_multicast(addr))
  		return -EINVAL;
  
  	err = -EADDRNOTAVAIL;
  
  	for_each_pmc_rtnl(inet, pmc) {
  		if (pmc->multi.imr_multiaddr.s_addr == addr &&
  		    pmc->multi.imr_ifindex == gsf->gf_interface)
  			break;
  	}
  	if (!pmc)		/* must have a prior join */
  		goto done;
  	gsf->gf_fmode = pmc->sfmode;
  	psl = rtnl_dereference(pmc->sflist);
  	count = psl ? psl->sl_count : 0;
  	copycount = count < gsf->gf_numsrc ? count : gsf->gf_numsrc;
  	gsf->gf_numsrc = count;
  	if (put_user(GROUP_FILTER_SIZE(copycount), optlen) ||
  	    copy_to_user(optval, gsf, GROUP_FILTER_SIZE(0))) {
  		return -EFAULT;
  	}
  	for (i = 0; i < copycount; i++) {
  		struct sockaddr_storage ss;
  
  		psin = (struct sockaddr_in *)&ss;
  		memset(&ss, 0, sizeof(ss));
  		psin->sin_family = AF_INET;
  		psin->sin_addr.s_addr = psl->sl_addr[i];
  		if (copy_to_user(&optval->gf_slist[i], &ss, sizeof(ss)))
  			return -EFAULT;
  	}
  	return 0;
  done:
  	return err;
  }
  
  /*
   * check if a multicast source filter allows delivery for a given <src,dst,intf>
   */
  int ip_mc_sf_allow(struct sock *sk, __be32 loc_addr, __be32 rmt_addr, int dif)
  {
  	struct inet_sock *inet = inet_sk(sk);
  	struct ip_mc_socklist *pmc;
  	struct ip_sf_socklist *psl;
  	int i;
  	int ret;
  
  	ret = 1;
  	if (!ipv4_is_multicast(loc_addr))
  		goto out;
  
  	rcu_read_lock();
  	for_each_pmc_rcu(inet, pmc) {
  		if (pmc->multi.imr_multiaddr.s_addr == loc_addr &&
  		    pmc->multi.imr_ifindex == dif)
  			break;
  	}
  	ret = inet->mc_all;
  	if (!pmc)
  		goto unlock;
  	psl = rcu_dereference(pmc->sflist);
  	ret = (pmc->sfmode == MCAST_EXCLUDE);
  	if (!psl)
  		goto unlock;
  
  	for (i = 0; i < psl->sl_count; i++) {
  		if (psl->sl_addr[i] == rmt_addr)
  			break;
  	}
  	ret = 0;
  	if (pmc->sfmode == MCAST_INCLUDE && i >= psl->sl_count)
  		goto unlock;
  	if (pmc->sfmode == MCAST_EXCLUDE && i < psl->sl_count)
  		goto unlock;
  	ret = 1;
  unlock:
  	rcu_read_unlock();
  out:
  	return ret;
  }
  
  /*
   *	A socket is closing.
   */
  
  void ip_mc_drop_socket(struct sock *sk)
  {
  	struct inet_sock *inet = inet_sk(sk);
  	struct ip_mc_socklist *iml;
  	struct net *net = sock_net(sk);
  
  	if (!inet->mc_list)
  		return;
  
  	rtnl_lock();
  	while ((iml = rtnl_dereference(inet->mc_list)) != NULL) {
  		struct in_device *in_dev;
  
  		inet->mc_list = iml->next_rcu;
  		in_dev = inetdev_by_index(net, iml->multi.imr_ifindex);
  		(void) ip_mc_leave_src(sk, iml, in_dev);
  		if (in_dev)
  			ip_mc_dec_group(in_dev, iml->multi.imr_multiaddr.s_addr);
  		/* decrease mem now to avoid the memleak warning */
  		atomic_sub(sizeof(*iml), &sk->sk_omem_alloc);
  		kfree_rcu(iml, rcu);
  	}
  	rtnl_unlock();
  }
  
  /* called with rcu_read_lock() */
  int ip_check_mc_rcu(struct in_device *in_dev, __be32 mc_addr, __be32 src_addr, u8 proto)
  {
  	struct ip_mc_list *im;
  	struct ip_mc_list __rcu **mc_hash;
  	struct ip_sf_list *psf;
  	int rv = 0;
  
  	mc_hash = rcu_dereference(in_dev->mc_hash);
  	if (mc_hash) {
  		u32 hash = hash_32((__force u32)mc_addr, MC_HASH_SZ_LOG);
  
  		for (im = rcu_dereference(mc_hash[hash]);
  		     im != NULL;
  		     im = rcu_dereference(im->next_hash)) {
  			if (im->multiaddr == mc_addr)
  				break;
  		}
  	} else {
  		for_each_pmc_rcu(in_dev, im) {
  			if (im->multiaddr == mc_addr)
  				break;
  		}
  	}
  	if (im && proto == IPPROTO_IGMP) {
  		rv = 1;
  	} else if (im) {
  		if (src_addr) {
  			for (psf = im->sources; psf; psf = psf->sf_next) {
  				if (psf->sf_inaddr == src_addr)
  					break;
  			}
  			if (psf)
  				rv = psf->sf_count[MCAST_INCLUDE] ||
  					psf->sf_count[MCAST_EXCLUDE] !=
  					im->sfcount[MCAST_EXCLUDE];
  			else
  				rv = im->sfcount[MCAST_EXCLUDE] != 0;
  		} else
  			rv = 1; /* unspecified source; tentatively allow */
  	}
  	return rv;
  }
  
  #if defined(CONFIG_PROC_FS)
  struct igmp_mc_iter_state {
  	struct seq_net_private p;
  	struct net_device *dev;
  	struct in_device *in_dev;
  };
  
  #define	igmp_mc_seq_private(seq)	((struct igmp_mc_iter_state *)(seq)->private)
  
  static inline struct ip_mc_list *igmp_mc_get_first(struct seq_file *seq)
  {
  	struct net *net = seq_file_net(seq);
  	struct ip_mc_list *im = NULL;
  	struct igmp_mc_iter_state *state = igmp_mc_seq_private(seq);
  
  	state->in_dev = NULL;
  	for_each_netdev_rcu(net, state->dev) {
  		struct in_device *in_dev;
  
  		in_dev = __in_dev_get_rcu(state->dev);
  		if (!in_dev)
  			continue;
  		im = rcu_dereference(in_dev->mc_list);
  		if (im) {
  			state->in_dev = in_dev;
  			break;
  		}
  	}
  	return im;
  }
  
  static struct ip_mc_list *igmp_mc_get_next(struct seq_file *seq, struct ip_mc_list *im)
  {
  	struct igmp_mc_iter_state *state = igmp_mc_seq_private(seq);
  
  	im = rcu_dereference(im->next_rcu);
  	while (!im) {
  		state->dev = next_net_device_rcu(state->dev);
  		if (!state->dev) {
  			state->in_dev = NULL;
  			break;
  		}
  		state->in_dev = __in_dev_get_rcu(state->dev);
  		if (!state->in_dev)
  			continue;
  		im = rcu_dereference(state->in_dev->mc_list);
  	}
  	return im;
  }
  
  static struct ip_mc_list *igmp_mc_get_idx(struct seq_file *seq, loff_t pos)
  {
  	struct ip_mc_list *im = igmp_mc_get_first(seq);
  	if (im)
  		while (pos && (im = igmp_mc_get_next(seq, im)) != NULL)
  			--pos;
  	return pos ? NULL : im;
  }
  
  static void *igmp_mc_seq_start(struct seq_file *seq, loff_t *pos)
  	__acquires(rcu)
  {
  	rcu_read_lock();
  	return *pos ? igmp_mc_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
  }
  
  static void *igmp_mc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
  {
  	struct ip_mc_list *im;
  	if (v == SEQ_START_TOKEN)
  		im = igmp_mc_get_first(seq);
  	else
  		im = igmp_mc_get_next(seq, v);
  	++*pos;
  	return im;
  }
  
  static void igmp_mc_seq_stop(struct seq_file *seq, void *v)
  	__releases(rcu)
  {
  	struct igmp_mc_iter_state *state = igmp_mc_seq_private(seq);
  
  	state->in_dev = NULL;
  	state->dev = NULL;
  	rcu_read_unlock();
  }
  
  static int igmp_mc_seq_show(struct seq_file *seq, void *v)
  {
  	if (v == SEQ_START_TOKEN)
  		seq_puts(seq,
  			 "Idx\tDevice    : Count Querier\tGroup    Users Timer\tReporter\n");
  	else {
  		struct ip_mc_list *im = (struct ip_mc_list *)v;
  		struct igmp_mc_iter_state *state = igmp_mc_seq_private(seq);
  		char   *querier;
  		long delta;
  
  #ifdef CONFIG_IP_MULTICAST
  		querier = IGMP_V1_SEEN(state->in_dev) ? "V1" :
  			  IGMP_V2_SEEN(state->in_dev) ? "V2" :
  			  "V3";
  #else
  		querier = "NONE";
  #endif
  
  		if (rcu_access_pointer(state->in_dev->mc_list) == im) {
  			seq_printf(seq, "%d\t%-10s: %5d %7s\n",
  				   state->dev->ifindex, state->dev->name, state->in_dev->mc_count, querier);
  		}
  
  		delta = im->timer.expires - jiffies;
  		seq_printf(seq,
  			   "\t\t\t\t%08X %5d %d:%08lX\t\t%d\n",
  			   im->multiaddr, im->users,
  			   im->tm_running,
  			   im->tm_running ? jiffies_delta_to_clock_t(delta) : 0,
  			   im->reporter);
  	}
  	return 0;
  }
  
  static const struct seq_operations igmp_mc_seq_ops = {
  	.start	=	igmp_mc_seq_start,
  	.next	=	igmp_mc_seq_next,
  	.stop	=	igmp_mc_seq_stop,
  	.show	=	igmp_mc_seq_show,
  };
  
  static int igmp_mc_seq_open(struct inode *inode, struct file *file)
  {
  	return seq_open_net(inode, file, &igmp_mc_seq_ops,
  			sizeof(struct igmp_mc_iter_state));
  }
  
  static const struct file_operations igmp_mc_seq_fops = {
  	.owner		=	THIS_MODULE,
  	.open		=	igmp_mc_seq_open,
  	.read		=	seq_read,
  	.llseek		=	seq_lseek,
  	.release	=	seq_release_net,
  };
  
  struct igmp_mcf_iter_state {
  	struct seq_net_private p;
  	struct net_device *dev;
  	struct in_device *idev;
  	struct ip_mc_list *im;
  };
  
  #define igmp_mcf_seq_private(seq)	((struct igmp_mcf_iter_state *)(seq)->private)
  
  static inline struct ip_sf_list *igmp_mcf_get_first(struct seq_file *seq)
  {
  	struct net *net = seq_file_net(seq);
  	struct ip_sf_list *psf = NULL;
  	struct ip_mc_list *im = NULL;
  	struct igmp_mcf_iter_state *state = igmp_mcf_seq_private(seq);
  
  	state->idev = NULL;
  	state->im = NULL;
  	for_each_netdev_rcu(net, state->dev) {
  		struct in_device *idev;
  		idev = __in_dev_get_rcu(state->dev);
  		if (unlikely(!idev))
  			continue;
  		im = rcu_dereference(idev->mc_list);
  		if (likely(im)) {
  			spin_lock_bh(&im->lock);
  			psf = im->sources;
  			if (likely(psf)) {
  				state->im = im;
  				state->idev = idev;
  				break;
  			}
  			spin_unlock_bh(&im->lock);
  		}
  	}
  	return psf;
  }
  
  static struct ip_sf_list *igmp_mcf_get_next(struct seq_file *seq, struct ip_sf_list *psf)
  {
  	struct igmp_mcf_iter_state *state = igmp_mcf_seq_private(seq);
  
  	psf = psf->sf_next;
  	while (!psf) {
  		spin_unlock_bh(&state->im->lock);
  		state->im = state->im->next;
  		while (!state->im) {
  			state->dev = next_net_device_rcu(state->dev);
  			if (!state->dev) {
  				state->idev = NULL;
  				goto out;
  			}
  			state->idev = __in_dev_get_rcu(state->dev);
  			if (!state->idev)
  				continue;
  			state->im = rcu_dereference(state->idev->mc_list);
  		}
  		if (!state->im)
  			break;
  		spin_lock_bh(&state->im->lock);
  		psf = state->im->sources;
  	}
  out:
  	return psf;
  }
  
  static struct ip_sf_list *igmp_mcf_get_idx(struct seq_file *seq, loff_t pos)
  {
  	struct ip_sf_list *psf = igmp_mcf_get_first(seq);
  	if (psf)
  		while (pos && (psf = igmp_mcf_get_next(seq, psf)) != NULL)
  			--pos;
  	return pos ? NULL : psf;
  }
  
  static void *igmp_mcf_seq_start(struct seq_file *seq, loff_t *pos)
  	__acquires(rcu)
  {
  	rcu_read_lock();
  	return *pos ? igmp_mcf_get_idx(seq, *pos - 1) : SEQ_START_TOKEN;
  }
  
  static void *igmp_mcf_seq_next(struct seq_file *seq, void *v, loff_t *pos)
  {
  	struct ip_sf_list *psf;
  	if (v == SEQ_START_TOKEN)
  		psf = igmp_mcf_get_first(seq);
  	else
  		psf = igmp_mcf_get_next(seq, v);
  	++*pos;
  	return psf;
  }
  
  static void igmp_mcf_seq_stop(struct seq_file *seq, void *v)
  	__releases(rcu)
  {
  	struct igmp_mcf_iter_state *state = igmp_mcf_seq_private(seq);
  	if (likely(state->im)) {
  		spin_unlock_bh(&state->im->lock);
  		state->im = NULL;
  	}
  	state->idev = NULL;
  	state->dev = NULL;
  	rcu_read_unlock();
  }
  
  static int igmp_mcf_seq_show(struct seq_file *seq, void *v)
  {
  	struct ip_sf_list *psf = (struct ip_sf_list *)v;
  	struct igmp_mcf_iter_state *state = igmp_mcf_seq_private(seq);
  
  	if (v == SEQ_START_TOKEN) {
  		seq_puts(seq, "Idx Device        MCA        SRC    INC    EXC\n");
  	} else {
  		seq_printf(seq,
  			   "%3d %6.6s 0x%08x "
  			   "0x%08x %6lu %6lu\n",
  			   state->dev->ifindex, state->dev->name,
  			   ntohl(state->im->multiaddr),
  			   ntohl(psf->sf_inaddr),
  			   psf->sf_count[MCAST_INCLUDE],
  			   psf->sf_count[MCAST_EXCLUDE]);
  	}
  	return 0;
  }
  
  static const struct seq_operations igmp_mcf_seq_ops = {
  	.start	=	igmp_mcf_seq_start,
  	.next	=	igmp_mcf_seq_next,
  	.stop	=	igmp_mcf_seq_stop,
  	.show	=	igmp_mcf_seq_show,
  };
  
  static int igmp_mcf_seq_open(struct inode *inode, struct file *file)
  {
  	return seq_open_net(inode, file, &igmp_mcf_seq_ops,
  			sizeof(struct igmp_mcf_iter_state));
  }
  
  static const struct file_operations igmp_mcf_seq_fops = {
  	.owner		=	THIS_MODULE,
  	.open		=	igmp_mcf_seq_open,
  	.read		=	seq_read,
  	.llseek		=	seq_lseek,
  	.release	=	seq_release_net,
  };
  
  static int __net_init igmp_net_init(struct net *net)
  {
  	struct proc_dir_entry *pde;
  	int err;
  
  	pde = proc_create("igmp", S_IRUGO, net->proc_net, &igmp_mc_seq_fops);
  	if (!pde)
  		goto out_igmp;
  	pde = proc_create("mcfilter", S_IRUGO, net->proc_net,
  			  &igmp_mcf_seq_fops);
  	if (!pde)
  		goto out_mcfilter;
  	err = inet_ctl_sock_create(&net->ipv4.mc_autojoin_sk, AF_INET,
  				   SOCK_DGRAM, 0, net);
  	if (err < 0) {
  		pr_err("Failed to initialize the IGMP autojoin socket (err %d)\n",
  		       err);
  		goto out_sock;
  	}
  
  	/* Sysctl initialization */
  	net->ipv4.sysctl_igmp_max_memberships = 20;
  	net->ipv4.sysctl_igmp_max_msf = 10;
  	/* IGMP reports for link-local multicast groups are enabled by default */
  	net->ipv4.sysctl_igmp_llm_reports = 1;
  	net->ipv4.sysctl_igmp_qrv = 2;
  	return 0;
  
  out_sock:
  	remove_proc_entry("mcfilter", net->proc_net);
  out_mcfilter:
  	remove_proc_entry("igmp", net->proc_net);
  out_igmp:
  	return -ENOMEM;
  }
  
  static void __net_exit igmp_net_exit(struct net *net)
  {
  	remove_proc_entry("mcfilter", net->proc_net);
  	remove_proc_entry("igmp", net->proc_net);
  	inet_ctl_sock_destroy(net->ipv4.mc_autojoin_sk);
  }
  
  static struct pernet_operations igmp_net_ops = {
  	.init = igmp_net_init,
  	.exit = igmp_net_exit,
  };
  #endif
  
  static int igmp_netdev_event(struct notifier_block *this,
  			     unsigned long event, void *ptr)
  {
  	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
  	struct in_device *in_dev;
  
  	switch (event) {
  	case NETDEV_RESEND_IGMP:
  		in_dev = __in_dev_get_rtnl(dev);
  		if (in_dev)
  			ip_mc_rejoin_groups(in_dev);
  		break;
  	default:
  		break;
  	}
  	return NOTIFY_DONE;
  }
  
  static struct notifier_block igmp_notifier = {
  	.notifier_call = igmp_netdev_event,
  };
  
  int __init igmp_mc_init(void)
  {
  #if defined(CONFIG_PROC_FS)
  	int err;
  
  	err = register_pernet_subsys(&igmp_net_ops);
  	if (err)
  		return err;
  	err = register_netdevice_notifier(&igmp_notifier);
  	if (err)
  		goto reg_notif_fail;
  	return 0;
  
  reg_notif_fail:
  	unregister_pernet_subsys(&igmp_net_ops);
  	return err;
  #else
  	return register_netdevice_notifier(&igmp_notifier);
  #endif
  }
  