diff --git a/pimd/pim_igmp.c b/pimd/pim_igmp.c
new file mode 100644
index 0000000..e38ac96
--- /dev/null
+++ b/pimd/pim_igmp.c
@@ -0,0 +1,1411 @@
+/*
+  PIM for Quagga
+  Copyright (C) 2008  Everton da Silva Marques
+
+  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.
+
+  This program is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  General Public License for more details.
+  
+  You should have received a copy of the GNU General Public License
+  along with this program; see the file COPYING; if not, write to the
+  Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston,
+  MA 02110-1301 USA
+  
+  $QuaggaId: $Format:%an, %ai, %h$ $
+*/
+
+#include <zebra.h>
+
+#include "memory.h"
+
+#include "pimd.h"
+#include "pim_igmp.h"
+#include "pim_igmpv3.h"
+#include "pim_iface.h"
+#include "pim_sock.h"
+#include "pim_mroute.h"
+#include "pim_str.h"
+#include "pim_util.h"
+#include "pim_time.h"
+#include "pim_zebra.h"
+
+#define IGMP_GRP_REC_TYPE_MODE_IS_INCLUDE        (1)
+#define IGMP_GRP_REC_TYPE_MODE_IS_EXCLUDE        (2)
+#define IGMP_GRP_REC_TYPE_CHANGE_TO_INCLUDE_MODE (3)
+#define IGMP_GRP_REC_TYPE_CHANGE_TO_EXCLUDE_MODE (4)
+#define IGMP_GRP_REC_TYPE_ALLOW_NEW_SOURCES      (5)
+#define IGMP_GRP_REC_TYPE_BLOCK_OLD_SOURCES      (6)
+
+static void group_timer_off(struct igmp_group *group);
+
+static struct igmp_group *find_group_by_addr(struct igmp_sock *igmp,
+					     struct in_addr group_addr);
+
+static int igmp_sock_open(struct in_addr ifaddr, int ifindex, uint32_t pim_options)
+{
+  int fd;
+  int join = 0;
+  struct in_addr group;
+
+  fd = pim_socket_mcast(IPPROTO_IGMP, ifaddr, 1 /* loop=true */);
+  if (fd < 0)
+    return -1;
+
+  if (PIM_IF_TEST_IGMP_LISTEN_ALLROUTERS(pim_options)) {
+    if (inet_aton(PIM_ALL_ROUTERS, &group)) {
+      if (!pim_socket_join(fd, group, ifaddr, ifindex))
+	++join;
+    }
+    else {
+      zlog_warn("%s %s: IGMP socket fd=%d interface %s: could not solve %s to group address: errno=%d: %s",
+		__FILE__, __PRETTY_FUNCTION__, fd, inet_ntoa(ifaddr),
+		PIM_ALL_ROUTERS, errno, strerror(errno));
+    }
+  }
+
+  /*
+    IGMP routers periodically send IGMP general queries to AllSystems=224.0.0.1
+    IGMP routers must receive general queries for querier election.
+  */
+  if (inet_aton(PIM_ALL_SYSTEMS, &group)) {
+    if (!pim_socket_join(fd, group, ifaddr, ifindex))
+      ++join;
+  }
+  else {
+    zlog_warn("%s %s: IGMP socket fd=%d interface %s: could not solve %s to group address: errno=%d: %s",
+	      __FILE__, __PRETTY_FUNCTION__, fd, inet_ntoa(ifaddr),
+	      PIM_ALL_SYSTEMS, errno, strerror(errno));
+  }
+
+  if (inet_aton(PIM_ALL_IGMP_ROUTERS, &group)) {
+    if (!pim_socket_join(fd, group, ifaddr, ifindex)) {
+      ++join;
+    }
+  }
+  else {
+      zlog_warn("%s %s: IGMP socket fd=%d interface %s: could not solve %s to group address: errno=%d: %s",
+		__FILE__, __PRETTY_FUNCTION__, fd, inet_ntoa(ifaddr),
+		PIM_ALL_IGMP_ROUTERS, errno, strerror(errno));
+  }    
+
+  if (!join) {
+    zlog_err("IGMP socket fd=%d could not join any group on interface address %s",
+	     fd, inet_ntoa(ifaddr));
+    close(fd);
+    fd = -1;
+  }
+
+  return fd;
+}
+
+#undef IGMP_SOCK_DUMP
+
+#ifdef IGMP_SOCK_DUMP
+static void igmp_sock_dump(array_t *igmp_sock_array)
+{
+  int size = array_size(igmp_sock_array);
+  for (int i = 0; i < size; ++i) {
+    
+    struct igmp_sock *igmp = array_get(igmp_sock_array, i);
+    
+    zlog_debug("%s %s: [%d/%d] igmp_addr=%s fd=%d",
+	       __FILE__, __PRETTY_FUNCTION__,
+	       i, size,
+	       inet_ntoa(igmp->ifaddr),
+	       igmp->fd);
+  }
+}
+#endif
+
+struct igmp_sock *pim_igmp_sock_lookup_ifaddr(struct list *igmp_sock_list,
+					      struct in_addr ifaddr)
+{
+  struct listnode  *sock_node;
+  struct igmp_sock *igmp;
+
+#ifdef IGMP_SOCK_DUMP
+  igmp_sock_dump(igmp_sock_list);
+#endif
+
+  for (ALL_LIST_ELEMENTS_RO(igmp_sock_list, sock_node, igmp))
+    if (ifaddr.s_addr == igmp->ifaddr.s_addr)
+      return igmp;
+
+  return 0;
+}
+
+struct igmp_sock *igmp_sock_lookup_by_fd(struct list *igmp_sock_list,
+					 int fd)
+{
+  struct listnode  *sock_node;
+  struct igmp_sock *igmp;
+
+  for (ALL_LIST_ELEMENTS_RO(igmp_sock_list, sock_node, igmp))
+    if (fd == igmp->fd)
+      return igmp;
+
+  return 0;
+}
+
+static int pim_igmp_other_querier_expire(struct thread *t)
+{
+  struct igmp_sock *igmp;
+
+  zassert(t);
+  igmp = THREAD_ARG(t);
+  zassert(igmp);
+
+  zassert(igmp->t_other_querier_timer);
+  zassert(!igmp->t_igmp_query_timer);
+
+  if (PIM_DEBUG_IGMP_TRACE) {
+    char ifaddr_str[100];
+    pim_inet4_dump("<ifaddr?>", igmp->ifaddr, ifaddr_str, sizeof(ifaddr_str));
+    zlog_debug("%s: Querier %s resuming",
+	       __PRETTY_FUNCTION__,
+	       ifaddr_str);
+  }
+
+  igmp->t_other_querier_timer = 0;
+
+  /*
+    We are the current querier, then
+    re-start sending general queries.
+  */
+  pim_igmp_general_query_on(igmp);
+
+  return 0;
+}
+
+void pim_igmp_other_querier_timer_on(struct igmp_sock *igmp)
+{
+  long other_querier_present_interval_msec;
+  struct pim_interface *pim_ifp;
+
+  zassert(igmp);
+  zassert(igmp->interface);
+  zassert(igmp->interface->info);
+
+  pim_ifp = igmp->interface->info;
+
+  if (igmp->t_other_querier_timer) {
+    /*
+      There is other querier present already,
+      then reset the other-querier-present timer.
+    */
+
+    if (PIM_DEBUG_IGMP_TRACE) {
+      char ifaddr_str[100];
+      pim_inet4_dump("<ifaddr?>", igmp->ifaddr, ifaddr_str, sizeof(ifaddr_str));
+      zlog_debug("Querier %s resetting TIMER event for Other-Querier-Present",
+		 ifaddr_str);
+    }
+
+    THREAD_OFF(igmp->t_other_querier_timer);
+    zassert(!igmp->t_other_querier_timer);
+  }
+  else {
+    /*
+      We are the current querier, then stop sending general queries:
+      igmp->t_igmp_query_timer = 0;
+    */
+    pim_igmp_general_query_off(igmp);
+  }
+
+  /*
+    Since this socket is starting the other-querier-present timer,
+    there should not be periodic query timer for this socket.
+   */
+  zassert(!igmp->t_igmp_query_timer);
+
+  /*
+    RFC 3376: 8.5. Other Querier Present Interval
+
+    The Other Querier Present Interval is the length of time that must
+    pass before a multicast router decides that there is no longer
+    another multicast router which should be the querier.  This value
+    MUST be ((the Robustness Variable) times (the Query Interval)) plus
+    (one half of one Query Response Interval).
+
+    other_querier_present_interval_msec = \
+      igmp->querier_robustness_variable * \
+      1000 * igmp->querier_query_interval + \
+      100 * (pim_ifp->query_max_response_time_dsec >> 1);
+  */
+  other_querier_present_interval_msec =
+    PIM_IGMP_OQPI_MSEC(igmp->querier_robustness_variable,
+		       igmp->querier_query_interval,
+		       pim_ifp->igmp_query_max_response_time_dsec);
+  
+  if (PIM_DEBUG_IGMP_TRACE) {
+    char ifaddr_str[100];
+    pim_inet4_dump("<ifaddr?>", igmp->ifaddr, ifaddr_str, sizeof(ifaddr_str));
+    zlog_debug("Querier %s scheduling %ld.%03ld sec TIMER event for Other-Querier-Present",
+	       ifaddr_str,
+	       other_querier_present_interval_msec / 1000,
+	       other_querier_present_interval_msec % 1000);
+  }
+  
+  THREAD_TIMER_MSEC_ON(master, igmp->t_other_querier_timer,
+		       pim_igmp_other_querier_expire,
+		       igmp, other_querier_present_interval_msec);
+}
+
+void pim_igmp_other_querier_timer_off(struct igmp_sock *igmp)
+{
+  zassert(igmp);
+
+  if (PIM_DEBUG_IGMP_TRACE) {
+    if (igmp->t_other_querier_timer) {
+      char ifaddr_str[100];
+      pim_inet4_dump("<ifaddr?>", igmp->ifaddr, ifaddr_str, sizeof(ifaddr_str));
+      zlog_debug("IGMP querier %s fd=%d cancelling other-querier-present TIMER event on %s",
+		 ifaddr_str, igmp->fd, igmp->interface->name);
+    }
+  }
+  THREAD_OFF(igmp->t_other_querier_timer);
+  zassert(!igmp->t_other_querier_timer);
+}
+
+static int recv_igmp_query(struct igmp_sock *igmp, int query_version,
+			   int max_resp_code,
+			   struct in_addr from, const char *from_str,
+			   char *igmp_msg, int igmp_msg_len)
+{
+  struct interface     *ifp;
+  struct pim_interface *pim_ifp;
+  uint8_t               resv_s_qrv;
+  uint8_t               s_flag;
+  uint8_t               qrv;
+  struct in_addr        group_addr;
+  uint16_t              recv_checksum;
+  uint16_t              checksum;
+
+  group_addr = *(struct in_addr *)(igmp_msg + 4);
+
+  ifp = igmp->interface;
+  pim_ifp = ifp->info;
+
+  recv_checksum = *(uint16_t *) (igmp_msg + IGMP_V3_CHECKSUM_OFFSET);
+
+  /* for computing checksum */
+  *(uint16_t *) (igmp_msg + IGMP_V3_CHECKSUM_OFFSET) = 0;
+
+  checksum = pim_inet_checksum(igmp_msg, igmp_msg_len);
+  if (checksum != recv_checksum) {
+    zlog_warn("Recv IGMP query v%d from %s on %s: checksum mismatch: received=%x computed=%x",
+	      query_version, from_str, ifp->name, recv_checksum, checksum);
+    return -1;
+  }
+
+  if (PIM_DEBUG_IGMP_PACKETS) {
+    char group_str[100];
+    pim_inet4_dump("<group?>", group_addr, group_str, sizeof(group_str));
+    zlog_debug("Recv IGMP query v%d from %s on %s: size=%d checksum=%x group=%s",
+	       query_version, from_str, ifp->name,
+	       igmp_msg_len, checksum, group_str);
+  }
+
+  /*
+    RFC 3376: 6.6.2. Querier Election
+
+    When a router receives a query with a lower IP address, it sets
+    the Other-Querier-Present timer to Other Querier Present Interval
+    and ceases to send queries on the network if it was the previously
+    elected querier.
+   */
+  if (ntohl(from.s_addr) < ntohl(igmp->ifaddr.s_addr)) {
+    
+    if (PIM_DEBUG_IGMP_TRACE) {
+      char ifaddr_str[100];
+      pim_inet4_dump("<ifaddr?>", igmp->ifaddr, ifaddr_str, sizeof(ifaddr_str));
+      zlog_debug("%s: local address %s (%u) lost querier election to %s (%u)",
+		 ifp->name,
+		 ifaddr_str, ntohl(igmp->ifaddr.s_addr),
+		 from_str, ntohl(from.s_addr));
+    }
+
+    pim_igmp_other_querier_timer_on(igmp);
+  }
+
+  /*
+    RFC 3376: 4.1.6. QRV (Querier's Robustness Variable)
+
+    Routers adopt the QRV value from the most recently received Query
+    as their own [Robustness Variable] value, unless that most
+    recently received QRV was zero, in which case the receivers use
+    the default [Robustness Variable] value specified in section 8.1
+    or a statically configured value.
+  */
+  resv_s_qrv = igmp_msg[8];
+  qrv = 7 & resv_s_qrv;
+  igmp->querier_robustness_variable = qrv ? qrv : pim_ifp->igmp_default_robustness_variable;
+
+  /*
+    RFC 3376: 4.1.7. QQIC (Querier's Query Interval Code)
+
+    Multicast routers that are not the current querier adopt the QQI
+    value from the most recently received Query as their own [Query
+    Interval] value, unless that most recently received QQI was zero,
+    in which case the receiving routers use the default.
+  */
+  if (igmp->t_other_querier_timer) {
+    /* other querier present */
+    uint8_t  qqic;
+    uint16_t qqi;
+    qqic = igmp_msg[9];
+    qqi = igmp_msg_decode8to16(qqic);
+    igmp->querier_query_interval = qqi ? qqi : pim_ifp->igmp_default_query_interval;
+
+    if (PIM_DEBUG_IGMP_TRACE) {
+      char ifaddr_str[100];
+      pim_inet4_dump("<ifaddr?>", igmp->ifaddr, ifaddr_str, sizeof(ifaddr_str));
+      zlog_debug("Querier %s new query interval is %s QQI=%u sec (recv QQIC=%02x from %s)",
+		 ifaddr_str,
+		 qqi ? "recv-non-default" : "default",
+		 igmp->querier_query_interval,
+		 qqic,
+		 from_str);
+    }
+  }
+
+  /*
+    RFC 3376: 6.6.1. Timer Updates
+
+    When a router sends or receives a query with a clear Suppress
+    Router-Side Processing flag, it must update its timers to reflect
+    the correct timeout values for the group or sources being queried.
+
+    General queries don't trigger timer update.
+  */
+  s_flag = (1 << 3) & resv_s_qrv;
+  if (!s_flag) {
+    /* s_flag is clear */
+
+    if (PIM_INADDR_IS_ANY(group_addr)) {
+      /* this is a general query */
+
+      /* log that general query should have the s_flag set */
+      zlog_warn("General IGMP query v%d from %s on %s: Router-Side Processing flag is clear",
+		query_version, from_str, ifp->name);
+    }
+    else {
+      struct igmp_group *group;
+
+      /* this is a non-general query: perform timer updates */
+
+      group = find_group_by_addr(igmp, group_addr);
+      if (group) {
+	int recv_num_sources = ntohs(*(uint16_t *)(igmp_msg + IGMP_V3_NUMSOURCES_OFFSET));
+
+	/*
+	  RFC 3376: 6.6.1. Timer Updates
+	  Query Q(G,A): Source Timer for sources in A are lowered to LMQT
+	  Query Q(G): Group Timer is lowered to LMQT
+	*/
+	if (recv_num_sources < 1) {
+	  /* Query Q(G): Group Timer is lowered to LMQT */
+
+	  igmp_group_timer_lower_to_lmqt(group);
+	}
+	else {
+	  /* Query Q(G,A): Source Timer for sources in A are lowered to LMQT */
+
+	  /* Scan sources in query and lower their timers to LMQT */
+	  struct in_addr *sources = (struct in_addr *)(igmp_msg + IGMP_V3_SOURCES_OFFSET);
+	  for (int i = 0; i < recv_num_sources; ++i) {
+	    struct in_addr src_addr = sources[i];
+	    struct igmp_source *src = igmp_find_source_by_addr(group, src_addr);
+	    if (src) {
+	      igmp_source_timer_lower_to_lmqt(src);
+	    }
+	  }
+	}
+
+      }
+      else {
+	char group_str[100];
+	pim_inet4_dump("<group?>", group_addr, group_str, sizeof(group_str));
+	zlog_warn("IGMP query v%d from %s on %s: could not find group %s for timer update",
+		  query_version, from_str, ifp->name, group_str);
+      }
+    }
+  } /* s_flag is clear: timer updates */
+  
+  return 0;
+}
+
+static int igmp_v3_report(struct igmp_sock *igmp,
+			  struct in_addr from, const char *from_str,
+			  char *igmp_msg, int igmp_msg_len)
+{
+  uint16_t          recv_checksum;
+  uint16_t          checksum;
+  int               num_groups;
+  uint8_t          *group_record;
+  uint8_t          *report_pastend = (uint8_t *) igmp_msg + igmp_msg_len;
+  struct interface *ifp = igmp->interface;
+
+  if (igmp_msg_len < IGMP_V3_MSG_MIN_SIZE) {
+    zlog_warn("Recv IGMP report v3 from %s on %s: size=%d shorter than minimum=%d",
+	      from_str, ifp->name, igmp_msg_len, IGMP_V3_MSG_MIN_SIZE);
+    return -1;
+  }
+
+  recv_checksum = *(uint16_t *) (igmp_msg + IGMP_V3_CHECKSUM_OFFSET);
+
+  /* for computing checksum */
+  *(uint16_t *) (igmp_msg + IGMP_V3_CHECKSUM_OFFSET) = 0;
+
+  checksum = pim_inet_checksum(igmp_msg, igmp_msg_len);
+  if (checksum != recv_checksum) {
+    zlog_warn("Recv IGMP report v3 from %s on %s: checksum mismatch: received=%x computed=%x",
+	      from_str, ifp->name, recv_checksum, checksum);
+    return -1;
+  }
+
+  num_groups = ntohs(*(uint16_t *) (igmp_msg + IGMP_V3_REPORT_NUMGROUPS_OFFSET));
+  if (num_groups < 1) {
+    zlog_warn("Recv IGMP report v3 from %s on %s: missing group records",
+	      from_str, ifp->name);
+    return -1;
+  }
+
+  if (PIM_DEBUG_IGMP_PACKETS) {
+    zlog_debug("Recv IGMP report v3 from %s on %s: size=%d checksum=%x groups=%d",
+	       from_str, ifp->name, igmp_msg_len, checksum, num_groups);
+  }
+
+  group_record = (uint8_t *) igmp_msg + IGMP_V3_REPORT_GROUPPRECORD_OFFSET;
+
+  /* Scan groups */
+  for (int i = 0; i < num_groups; ++i) {
+    struct in_addr  rec_group;
+    uint8_t        *sources;
+    uint8_t        *src;
+    int             rec_type;
+    int             rec_auxdatalen;
+    int             rec_num_sources;
+    int             j;
+
+    if ((group_record + IGMP_V3_GROUP_RECORD_MIN_SIZE) > report_pastend) {
+      zlog_warn("Recv IGMP report v3 from %s on %s: group record beyond report end",
+		from_str, ifp->name);
+      return -1;
+    }
+
+    rec_type        = group_record[IGMP_V3_GROUP_RECORD_TYPE_OFFSET];
+    rec_auxdatalen  = group_record[IGMP_V3_GROUP_RECORD_AUXDATALEN_OFFSET];
+    rec_num_sources = ntohs(* (uint16_t *) (group_record + IGMP_V3_GROUP_RECORD_NUMSOURCES_OFFSET));
+
+    rec_group = *(struct in_addr *)(group_record + IGMP_V3_GROUP_RECORD_GROUP_OFFSET);
+
+    if (PIM_DEBUG_IGMP_PACKETS) {
+      zlog_debug("Recv IGMP report v3 from %s on %s: record=%d type=%d auxdatalen=%d sources=%d group=%s",
+		 from_str, ifp->name, i, rec_type, rec_auxdatalen, rec_num_sources, inet_ntoa(rec_group));
+    }
+
+    /* Scan sources */
+    
+    sources = group_record + IGMP_V3_GROUP_RECORD_SOURCE_OFFSET;
+
+    for (j = 0, src = sources; j < rec_num_sources; ++j, src += 4) {
+
+      if ((src + 4) > report_pastend) {
+	zlog_warn("Recv IGMP report v3 from %s on %s: group source beyond report end",
+		  from_str, ifp->name);
+	return -1;
+      }
+
+      if (PIM_DEBUG_IGMP_PACKETS) {
+	char src_str[200];
+
+	if (!inet_ntop(AF_INET, src, src_str , sizeof(src_str)))
+	  sprintf(src_str, "<source?>");
+	
+	zlog_debug("Recv IGMP report v3 from %s on %s: record=%d group=%s source=%s",
+		   from_str, ifp->name, i, inet_ntoa(rec_group), src_str);
+      }
+    } /* for (sources) */
+
+    switch (rec_type) {
+    case IGMP_GRP_REC_TYPE_MODE_IS_INCLUDE:
+      igmpv3_report_isin(igmp, from, rec_group, rec_num_sources, (struct in_addr *) sources);
+      break;
+    case IGMP_GRP_REC_TYPE_MODE_IS_EXCLUDE:
+      igmpv3_report_isex(igmp, from, rec_group, rec_num_sources, (struct in_addr *) sources);
+      break;
+    case IGMP_GRP_REC_TYPE_CHANGE_TO_INCLUDE_MODE:
+      igmpv3_report_toin(igmp, from, rec_group, rec_num_sources, (struct in_addr *) sources);
+      break;
+    case IGMP_GRP_REC_TYPE_CHANGE_TO_EXCLUDE_MODE:
+      igmpv3_report_toex(igmp, from, rec_group, rec_num_sources, (struct in_addr *) sources);
+      break;
+    case IGMP_GRP_REC_TYPE_ALLOW_NEW_SOURCES:
+      igmpv3_report_allow(igmp, from, rec_group, rec_num_sources, (struct in_addr *) sources);
+      break;
+    case IGMP_GRP_REC_TYPE_BLOCK_OLD_SOURCES:
+      igmpv3_report_block(igmp, from, rec_group, rec_num_sources, (struct in_addr *) sources);
+      break;
+    default:
+      zlog_warn("Recv IGMP report v3 from %s on %s: unknown record type: type=%d",
+		from_str, ifp->name, rec_type);
+    }
+
+    group_record += 8 + (rec_num_sources << 2) + (rec_auxdatalen << 2);
+
+  } /* for (group records) */
+
+  return 0;
+}
+
+static void on_trace(const char *label,
+		     struct interface *ifp, struct in_addr from)
+{
+  if (PIM_DEBUG_IGMP_TRACE) {
+    char from_str[100];
+    pim_inet4_dump("<from?>", from, from_str, sizeof(from_str));
+    zlog_debug("%s: from %s on %s",
+	       label, from_str, ifp->name);
+  }
+}
+
+static int igmp_v2_report(struct igmp_sock *igmp,
+			  struct in_addr from, const char *from_str,
+			  char *igmp_msg, int igmp_msg_len)
+{
+  struct interface *ifp = igmp->interface;
+  struct igmp_group *group;
+  struct in_addr group_addr;
+
+  on_trace(__PRETTY_FUNCTION__, igmp->interface, from);
+
+  if (igmp_msg_len != IGMP_V12_MSG_SIZE) {
+    zlog_warn("Recv IGMP report v2 from %s on %s: size=%d other than correct=%d",
+	      from_str, ifp->name, igmp_msg_len, IGMP_V12_MSG_SIZE);
+    return -1;
+  }
+
+  if (PIM_DEBUG_IGMP_TRACE) {
+    zlog_warn("%s %s: FIXME WRITEME",
+	      __FILE__, __PRETTY_FUNCTION__);
+  }
+
+  group_addr = *(struct in_addr *)(igmp_msg + 4);
+
+  /* non-existant group is created as INCLUDE {empty} */
+  group = igmp_add_group_by_addr(igmp, group_addr, ifp->name);
+  if (!group) {
+    return -1;
+  }
+
+  group->last_igmp_v2_report_dsec = pim_time_monotonic_dsec();
+
+  return 0;
+}
+
+static int igmp_v2_leave(struct igmp_sock *igmp,
+			 struct in_addr from, const char *from_str,
+			 char *igmp_msg, int igmp_msg_len)
+{
+  struct interface *ifp = igmp->interface;
+
+  on_trace(__PRETTY_FUNCTION__, igmp->interface, from);
+
+  if (igmp_msg_len != IGMP_V12_MSG_SIZE) {
+    zlog_warn("Recv IGMP leave v2 from %s on %s: size=%d other than correct=%d",
+	      from_str, ifp->name, igmp_msg_len, IGMP_V12_MSG_SIZE);
+    return -1;
+  }
+
+  if (PIM_DEBUG_IGMP_TRACE) {
+    zlog_warn("%s %s: FIXME WRITEME",
+	      __FILE__, __PRETTY_FUNCTION__);
+  }
+
+  return 0;
+}
+
+static int igmp_v1_report(struct igmp_sock *igmp,
+			  struct in_addr from, const char *from_str,
+			  char *igmp_msg, int igmp_msg_len)
+{
+  struct interface *ifp = igmp->interface;
+  struct igmp_group *group;
+  struct in_addr group_addr;
+
+  on_trace(__PRETTY_FUNCTION__, igmp->interface, from);
+
+  if (igmp_msg_len != IGMP_V12_MSG_SIZE) {
+    zlog_warn("Recv IGMP report v1 from %s on %s: size=%d other than correct=%d",
+	      from_str, ifp->name, igmp_msg_len, IGMP_V12_MSG_SIZE);
+    return -1;
+  }
+
+  if (PIM_DEBUG_IGMP_TRACE) {
+    zlog_warn("%s %s: FIXME WRITEME",
+	      __FILE__, __PRETTY_FUNCTION__);
+  }
+
+  group_addr = *(struct in_addr *)(igmp_msg + 4);
+
+  /* non-existant group is created as INCLUDE {empty} */
+  group = igmp_add_group_by_addr(igmp, group_addr, ifp->name);
+  if (!group) {
+    return -1;
+  }
+
+  group->last_igmp_v1_report_dsec = pim_time_monotonic_dsec();
+
+  return 0;
+}
+
+int pim_igmp_packet(struct igmp_sock *igmp, char *buf, size_t len)
+{
+  struct ip *ip_hdr;
+  size_t ip_hlen; /* ip header length in bytes */
+  char *igmp_msg;
+  int igmp_msg_len;
+  int msg_type;
+  char from_str[100];
+  char to_str[100];
+    
+  if (len < sizeof(*ip_hdr)) {
+    zlog_warn("IGMP packet size=%d shorter than minimum=%d",
+	      len, sizeof(*ip_hdr));
+    return -1;
+  }
+
+  ip_hdr = (struct ip *) buf;
+
+  pim_inet4_dump("<src?>", ip_hdr->ip_src, from_str , sizeof(from_str));
+  pim_inet4_dump("<dst?>", ip_hdr->ip_dst, to_str , sizeof(to_str));
+
+  ip_hlen = ip_hdr->ip_hl << 2; /* ip_hl gives length in 4-byte words */
+
+  if (PIM_DEBUG_IGMP_PACKETS) {
+    zlog_debug("Recv IP packet from %s to %s on %s: size=%d ip_header_size=%d ip_proto=%d",
+	       from_str, to_str, igmp->interface->name, len, ip_hlen, ip_hdr->ip_p);
+  }
+
+  if (ip_hdr->ip_p != PIM_IP_PROTO_IGMP) {
+    zlog_warn("IP packet protocol=%d is not IGMP=%d",
+	      ip_hdr->ip_p, PIM_IP_PROTO_IGMP);
+    return -1;
+  }
+
+  if (ip_hlen < PIM_IP_HEADER_MIN_LEN) {
+    zlog_warn("IP packet header size=%d shorter than minimum=%d",
+	      ip_hlen, PIM_IP_HEADER_MIN_LEN);
+    return -1;
+  }
+  if (ip_hlen > PIM_IP_HEADER_MAX_LEN) {
+    zlog_warn("IP packet header size=%d greater than maximum=%d",
+	      ip_hlen, PIM_IP_HEADER_MAX_LEN);
+    return -1;
+  }
+
+  igmp_msg = buf + ip_hlen;
+  msg_type = *igmp_msg;
+  igmp_msg_len = len - ip_hlen;
+
+  if (PIM_DEBUG_IGMP_PACKETS) {
+    zlog_debug("Recv IGMP packet from %s to %s on %s: ttl=%d msg_type=%d msg_size=%d",
+	       from_str, to_str, igmp->interface->name, ip_hdr->ip_ttl, msg_type,
+	       igmp_msg_len);
+  }
+
+  if (igmp_msg_len < PIM_IGMP_MIN_LEN) {
+    zlog_warn("IGMP message size=%d shorter than minimum=%d",
+	      igmp_msg_len, PIM_IGMP_MIN_LEN);
+    return -1;
+  }
+
+  switch (msg_type) {
+  case PIM_IGMP_MEMBERSHIP_QUERY:
+    {
+      int max_resp_code = igmp_msg[1];
+      int query_version;
+
+      /*
+	RFC 3376: 7.1. Query Version Distinctions
+	IGMPv1 Query: length = 8 octets AND Max Resp Code field is zero
+	IGMPv2 Query: length = 8 octets AND Max Resp Code field is non-zero
+	IGMPv3 Query: length >= 12 octets
+      */
+
+      if (igmp_msg_len == 8) {
+	query_version = max_resp_code ? 2 : 1;
+      }
+      else if (igmp_msg_len >= 12) {
+	query_version = 3;
+      }
+      else {
+	zlog_warn("Unknown IGMP query version");
+	return -1;
+      }
+
+      return recv_igmp_query(igmp, query_version, max_resp_code,
+			     ip_hdr->ip_src, from_str,
+			     igmp_msg, igmp_msg_len);
+    }
+
+  case PIM_IGMP_V3_MEMBERSHIP_REPORT:
+    return igmp_v3_report(igmp, ip_hdr->ip_src, from_str,
+			  igmp_msg, igmp_msg_len);
+
+  case PIM_IGMP_V2_MEMBERSHIP_REPORT:
+    return igmp_v2_report(igmp, ip_hdr->ip_src, from_str,
+			  igmp_msg, igmp_msg_len);
+
+  case PIM_IGMP_V1_MEMBERSHIP_REPORT:
+    return igmp_v1_report(igmp, ip_hdr->ip_src, from_str,
+			  igmp_msg, igmp_msg_len);
+
+  case PIM_IGMP_V2_LEAVE_GROUP:
+    return igmp_v2_leave(igmp, ip_hdr->ip_src, from_str,
+			 igmp_msg, igmp_msg_len);
+  }
+
+  zlog_warn("Ignoring unsupported IGMP message type: %d", msg_type);
+
+  return -1;
+}
+
+static int pim_igmp_general_query(struct thread *t);
+
+void pim_igmp_general_query_on(struct igmp_sock *igmp)
+{
+  struct pim_interface *pim_ifp;
+  int startup_mode;
+  int query_interval;
+
+  zassert(igmp);
+  zassert(igmp->interface);
+
+  /*
+    Since this socket is starting as querier,
+    there should not exist a timer for other-querier-present.
+   */
+  zassert(!igmp->t_other_querier_timer);
+  pim_ifp = igmp->interface->info;
+  zassert(pim_ifp);
+
+  /*
+    RFC 3376: 8.6. Startup Query Interval
+
+    The Startup Query Interval is the interval between General Queries
+    sent by a Querier on startup.  Default: 1/4 the Query Interval.
+  */
+  startup_mode = igmp->startup_query_count > 0;
+  if (startup_mode) {
+    --igmp->startup_query_count;
+
+    /* query_interval = pim_ifp->igmp_default_query_interval >> 2; */
+    query_interval = PIM_IGMP_SQI(pim_ifp->igmp_default_query_interval);
+  }
+  else {
+    query_interval = igmp->querier_query_interval;
+  }
+
+  if (PIM_DEBUG_IGMP_TRACE) {
+    char ifaddr_str[100];
+    pim_inet4_dump("<ifaddr?>", igmp->ifaddr, ifaddr_str, sizeof(ifaddr_str));
+    zlog_debug("Querier %s scheduling %d-second (%s) TIMER event for IGMP query on fd=%d",
+	       ifaddr_str,
+	       query_interval,
+	       startup_mode ? "startup" : "non-startup",
+	       igmp->fd);
+  }
+  igmp->t_igmp_query_timer = 0;
+  zassert(!igmp->t_igmp_query_timer);
+  THREAD_TIMER_ON(master, igmp->t_igmp_query_timer,
+		  pim_igmp_general_query,
+		  igmp, query_interval);
+}
+
+void pim_igmp_general_query_off(struct igmp_sock *igmp)
+{
+  zassert(igmp);
+
+  if (PIM_DEBUG_IGMP_TRACE) {
+    if (igmp->t_igmp_query_timer) {
+      char ifaddr_str[100];
+      pim_inet4_dump("<ifaddr?>", igmp->ifaddr, ifaddr_str, sizeof(ifaddr_str));
+      zlog_debug("IGMP querier %s fd=%d cancelling query TIMER event on %s",
+		 ifaddr_str, igmp->fd, igmp->interface->name);
+    }
+  }
+  THREAD_OFF(igmp->t_igmp_query_timer);
+  zassert(!igmp->t_igmp_query_timer);
+}
+
+/* Issue IGMP general query */
+static int pim_igmp_general_query(struct thread *t)
+{
+  char   query_buf[PIM_IGMP_BUFSIZE_WRITE];
+  struct igmp_sock *igmp;
+  struct in_addr dst_addr;
+  struct in_addr group_addr;
+  struct pim_interface *pim_ifp;
+
+  zassert(t);
+
+  igmp = THREAD_ARG(t);
+
+  zassert(igmp);
+  zassert(igmp->interface);
+  zassert(igmp->interface->info);
+
+  pim_ifp = igmp->interface->info;
+
+  /*
+    RFC3376: 4.1.12. IP Destination Addresses for Queries
+
+    In IGMPv3, General Queries are sent with an IP destination address
+    of 224.0.0.1, the all-systems multicast address.  Group-Specific
+    and Group-and-Source-Specific Queries are sent with an IP
+    destination address equal to the multicast address of interest.
+  */
+
+  dst_addr.s_addr   = htonl(INADDR_ALLHOSTS_GROUP);
+  group_addr.s_addr = PIM_NET_INADDR_ANY;
+
+  if (PIM_DEBUG_IGMP_TRACE) {
+    char querier_str[100];
+    char dst_str[100];
+    pim_inet4_dump("<querier?>", igmp->ifaddr, querier_str,
+		   sizeof(querier_str));
+    pim_inet4_dump("<dst?>", dst_addr, dst_str, sizeof(dst_str));
+    zlog_debug("Querier %s issuing IGMP general query to %s on %s",
+	       querier_str, dst_str, igmp->interface->name);
+  }
+
+  pim_igmp_send_membership_query(0 /* igmp_group */,
+				 igmp->fd,
+				 igmp->interface->name,
+				 query_buf,
+				 sizeof(query_buf),
+				 0 /* num_sources */,
+				 dst_addr,
+				 group_addr,
+				 pim_ifp->igmp_query_max_response_time_dsec,
+				 1 /* s_flag: always set for general queries */,
+				 igmp->querier_robustness_variable,
+				 igmp->querier_query_interval);
+
+  pim_igmp_general_query_on(igmp);
+
+  return 0;
+}
+
+static int pim_igmp_read(struct thread *t);
+
+static void igmp_read_on(struct igmp_sock *igmp)
+{
+  zassert(igmp);
+
+  if (PIM_DEBUG_IGMP_TRACE) {
+    zlog_debug("Scheduling READ event on IGMP socket fd=%d",
+	       igmp->fd);
+  }
+  igmp->t_igmp_read = 0;
+  zassert(!igmp->t_igmp_read);
+  THREAD_READ_ON(master, igmp->t_igmp_read, pim_igmp_read, igmp, igmp->fd);
+}
+
+static int pim_igmp_read(struct thread *t)
+{
+  struct igmp_sock *igmp;
+  int fd;
+  struct sockaddr_in from;
+  struct sockaddr_in to;
+  socklen_t fromlen = sizeof(from);
+  socklen_t tolen = sizeof(to);
+  char buf[PIM_IGMP_BUFSIZE_READ];
+  int len;
+  int ifindex = -1;
+  int result = -1; /* defaults to bad */
+
+  zassert(t);
+
+  igmp = THREAD_ARG(t);
+
+  zassert(igmp);
+
+  fd = THREAD_FD(t);
+
+  zassert(fd == igmp->fd);
+
+  len = pim_socket_recvfromto(fd, buf, sizeof(buf),
+			      &from, &fromlen,
+			      &to, &tolen,
+			      &ifindex);
+  if (len < 0) {
+    zlog_warn("Failure receiving IP IGMP packet on fd=%d: errno=%d: %s",
+	      fd, errno, strerror(errno));
+    goto done;
+  }
+
+  if (PIM_DEBUG_IGMP_PACKETS) {
+    char from_str[100];
+    char to_str[100];
+    
+    if (!inet_ntop(AF_INET, &from.sin_addr, from_str, sizeof(from_str)))
+      sprintf(from_str, "<from?>");
+    if (!inet_ntop(AF_INET, &to.sin_addr, to_str, sizeof(to_str)))
+      sprintf(to_str, "<to?>");
+    
+    zlog_debug("Recv IP IGMP pkt size=%d from %s to %s on fd=%d on ifindex=%d (sock_ifindex=%d)",
+	       len, from_str, to_str, fd, ifindex, igmp->interface->ifindex);
+  }
+
+#ifdef PIM_CHECK_RECV_IFINDEX_SANITY
+  /* ifindex sanity check */
+  if (ifindex != (int) igmp->interface->ifindex) {
+    char from_str[100];
+    char to_str[100];
+    struct interface *ifp;
+
+    if (!inet_ntop(AF_INET, &from.sin_addr, from_str , sizeof(from_str)))
+      sprintf(from_str, "<from?>");
+    if (!inet_ntop(AF_INET, &to.sin_addr, to_str , sizeof(to_str)))
+      sprintf(to_str, "<to?>");
+
+    ifp = if_lookup_by_index(ifindex);
+    if (ifp) {
+      zassert(ifindex == (int) ifp->ifindex);
+    }
+
+#ifdef PIM_REPORT_RECV_IFINDEX_MISMATCH
+    zlog_warn("Interface mismatch: recv IGMP pkt from %s to %s on fd=%d: recv_ifindex=%d (%s) sock_ifindex=%d (%s)",
+	      from_str, to_str, fd,
+	      ifindex, ifp ? ifp->name : "<if-notfound>",
+	      igmp->interface->ifindex, igmp->interface->name);
+#endif
+    goto done;
+  }
+#endif
+
+  if (pim_igmp_packet(igmp, buf, len)) {
+    goto done;
+  }
+
+  result = 0; /* good */
+
+ done:
+  igmp_read_on(igmp);
+
+  return result;
+}
+
+static void sock_close(struct igmp_sock *igmp)
+{
+  pim_igmp_other_querier_timer_off(igmp);
+  pim_igmp_general_query_off(igmp);
+
+  if (PIM_DEBUG_IGMP_TRACE) {
+    if (igmp->t_igmp_read) {
+      zlog_debug("Cancelling READ event on IGMP socket %s fd=%d on interface %s",
+		 inet_ntoa(igmp->ifaddr), igmp->fd,
+		 igmp->interface->name);
+    }
+  }
+  THREAD_OFF(igmp->t_igmp_read);
+  zassert(!igmp->t_igmp_read);
+  
+  if (close(igmp->fd)) {
+    zlog_err("Failure closing IGMP socket %s fd=%d on interface %s: errno=%d: %s",
+	     inet_ntoa(igmp->ifaddr), igmp->fd, igmp->interface->name,
+	     errno, strerror(errno));
+  }
+  
+  if (PIM_DEBUG_IGMP_TRACE) {
+    zlog_debug("Deleted IGMP socket %s fd=%d on interface %s",
+	       inet_ntoa(igmp->ifaddr), igmp->fd, igmp->interface->name);
+  }
+}
+
+void igmp_startup_mode_on(struct igmp_sock *igmp)
+{
+  struct pim_interface *pim_ifp;
+
+  pim_ifp = igmp->interface->info;
+
+  /*
+    RFC 3376: 8.7. Startup Query Count
+
+    The Startup Query Count is the number of Queries sent out on
+    startup, separated by the Startup Query Interval.  Default: the
+    Robustness Variable.
+  */
+  igmp->startup_query_count = igmp->querier_robustness_variable;
+
+  /*
+    Since we're (re)starting, reset QQI to default Query Interval
+  */
+  igmp->querier_query_interval = pim_ifp->igmp_default_query_interval;
+}
+
+static void igmp_group_free(struct igmp_group *group)
+{
+  zassert(!group->t_group_query_retransmit_timer);
+  zassert(!group->t_group_timer);
+  zassert(group->group_source_list);
+  zassert(!listcount(group->group_source_list));
+
+  list_free(group->group_source_list);
+
+  XFREE(MTYPE_PIM_IGMP_GROUP, group);
+}
+
+static void igmp_group_delete(struct igmp_group *group)
+{
+  struct listnode *src_node;
+  struct listnode *src_nextnode;
+  struct igmp_source *src;
+
+  if (PIM_DEBUG_IGMP_TRACE) {
+    char group_str[100];
+    pim_inet4_dump("<group?>", group->group_addr, group_str, sizeof(group_str));
+    zlog_debug("Deleting IGMP group %s from socket %d interface %s",
+	       group_str,
+	       group->group_igmp_sock->fd,
+	       group->group_igmp_sock->interface->name);
+  }
+
+  for (ALL_LIST_ELEMENTS(group->group_source_list, src_node, src_nextnode, src)) {
+    igmp_source_delete(src);
+  }
+
+  if (group->t_group_query_retransmit_timer) {
+    THREAD_OFF(group->t_group_query_retransmit_timer);
+    zassert(!group->t_group_query_retransmit_timer);
+  }
+
+  group_timer_off(group);
+  listnode_delete(group->group_igmp_sock->igmp_group_list, group);
+  igmp_group_free(group);
+}
+
+void igmp_group_delete_empty_include(struct igmp_group *group)
+{
+  zassert(!group->group_filtermode_isexcl);
+  zassert(!listcount(group->group_source_list));
+
+  igmp_group_delete(group);
+}
+
+void igmp_sock_free(struct igmp_sock *igmp)
+{
+  zassert(!igmp->t_igmp_read);
+  zassert(!igmp->t_igmp_query_timer);
+  zassert(!igmp->t_other_querier_timer);
+  zassert(igmp->igmp_group_list);
+  zassert(!listcount(igmp->igmp_group_list));
+
+  list_free(igmp->igmp_group_list);
+
+  XFREE(MTYPE_PIM_IGMP_SOCKET, igmp);
+}
+
+void igmp_sock_delete(struct igmp_sock *igmp)
+{
+  struct pim_interface *pim_ifp;
+  struct listnode      *grp_node;
+  struct listnode      *grp_nextnode;
+  struct igmp_group    *grp;
+
+  for (ALL_LIST_ELEMENTS(igmp->igmp_group_list, grp_node, grp_nextnode, grp)) {
+    igmp_group_delete(grp);
+  }
+
+  sock_close(igmp);
+
+  pim_ifp = igmp->interface->info;
+
+  listnode_delete(pim_ifp->igmp_socket_list, igmp);
+
+  igmp_sock_free(igmp);
+}
+
+static struct igmp_sock *igmp_sock_new(int fd,
+				       struct in_addr ifaddr,
+				       struct interface *ifp)
+{
+  struct pim_interface *pim_ifp;
+  struct igmp_sock *igmp;
+
+  pim_ifp = ifp->info;
+
+  if (PIM_DEBUG_IGMP_TRACE) {
+    zlog_debug("Creating IGMP socket fd=%d for address %s on interface %s",
+	       fd, inet_ntoa(ifaddr), ifp->name);
+  }
+
+  igmp = XMALLOC(MTYPE_PIM_IGMP_SOCKET, sizeof(*igmp));
+  if (!igmp) {
+    zlog_warn("%s %s: XMALLOC() failure",
+              __FILE__, __PRETTY_FUNCTION__);
+    return 0;
+  }
+
+  igmp->igmp_group_list = list_new();
+  if (!igmp->igmp_group_list) {
+    zlog_err("%s %s: failure: igmp_group_list = list_new()",
+	     __FILE__, __PRETTY_FUNCTION__);
+    return 0;
+  }
+  igmp->igmp_group_list->del = (void (*)(void *)) igmp_group_free;
+
+  igmp->fd                          = fd;
+  igmp->interface                   = ifp;
+  igmp->ifaddr                      = ifaddr;
+  igmp->t_igmp_read                 = 0;
+  igmp->t_igmp_query_timer          = 0;
+  igmp->t_other_querier_timer       = 0; /* no other querier present */
+  igmp->querier_robustness_variable = pim_ifp->igmp_default_robustness_variable;
+  igmp->sock_creation               = pim_time_monotonic_sec();
+
+  /*
+    igmp_startup_mode_on() will reset QQI:
+
+    igmp->querier_query_interval = pim_ifp->igmp_default_query_interval;
+  */
+  igmp_startup_mode_on(igmp);
+
+  igmp_read_on(igmp);
+  pim_igmp_general_query_on(igmp);
+
+  return igmp;
+}
+
+struct igmp_sock *pim_igmp_sock_add(struct list *igmp_sock_list,
+				    struct in_addr ifaddr,
+				    struct interface *ifp)
+{
+  struct pim_interface *pim_ifp;
+  struct igmp_sock *igmp;
+  int fd;
+
+  pim_ifp = ifp->info;
+
+  fd = igmp_sock_open(ifaddr, ifp->ifindex, pim_ifp->options);
+  if (fd < 0) {
+    zlog_warn("Could not open IGMP socket for %s on %s",
+	      inet_ntoa(ifaddr), ifp->name);
+    return 0;
+  }
+
+  igmp = igmp_sock_new(fd, ifaddr, ifp);
+  if (!igmp) {
+    zlog_err("%s %s: igmp_sock_new() failure",
+	     __FILE__, __PRETTY_FUNCTION__);
+    close(fd);
+    return 0;
+  }
+
+  listnode_add(igmp_sock_list, igmp);
+
+#ifdef IGMP_SOCK_DUMP
+  igmp_sock_dump(igmp_sock_array);
+#endif
+
+  return igmp;
+}
+
+/*
+  RFC 3376: 6.5. Switching Router Filter-Modes
+
+  When a router's filter-mode for a group is EXCLUDE and the group
+  timer expires, the router filter-mode for the group transitions to
+  INCLUDE.
+
+  A router uses source records with running source timers as its state
+  for the switch to a filter-mode of INCLUDE.  If there are any source
+  records with source timers greater than zero (i.e., requested to be
+  forwarded), a router switches to filter-mode of INCLUDE using those
+  source records.  Source records whose timers are zero (from the
+  previous EXCLUDE mode) are deleted.
+ */
+static int igmp_group_timer(struct thread *t)
+{
+  struct igmp_group *group;
+
+  zassert(t);
+  group = THREAD_ARG(t);
+  zassert(group);
+
+  if (PIM_DEBUG_IGMP_TRACE) {
+    char group_str[100];
+    pim_inet4_dump("<group?>", group->group_addr, group_str, sizeof(group_str));
+    zlog_debug("%s: Timer for group %s on interface %s",
+	       __PRETTY_FUNCTION__,
+	       group_str, group->group_igmp_sock->interface->name);
+  }
+
+  zassert(group->group_filtermode_isexcl);
+
+  group->t_group_timer = 0;
+  group->group_filtermode_isexcl = 0;
+
+  /* Any source (*,G) is forwarded only if mode is EXCLUDE {empty} */
+  igmp_anysource_forward_stop(group);
+
+  igmp_source_delete_expired(group->group_source_list);
+
+  zassert(!group->t_group_timer);
+  zassert(!group->group_filtermode_isexcl);
+
+  /*
+    RFC 3376: 6.2.2. Definition of Group Timers
+
+    If there are no more source records for the group, delete group
+    record.
+  */
+  if (listcount(group->group_source_list) < 1) {
+    igmp_group_delete_empty_include(group);
+  }
+
+  return 0;
+}
+
+static void group_timer_off(struct igmp_group *group)
+{
+  if (!group->t_group_timer)
+    return;
+
+  if (PIM_DEBUG_IGMP_TRACE) {
+    char group_str[100];
+    pim_inet4_dump("<group?>", group->group_addr, group_str, sizeof(group_str));
+    zlog_debug("Cancelling TIMER event for group %s on %s",
+	       group_str, group->group_igmp_sock->interface->name);
+  }
+    
+  THREAD_OFF(group->t_group_timer);
+  zassert(!group->t_group_timer);
+}
+
+void igmp_group_timer_on(struct igmp_group *group,
+			 long interval_msec, const char *ifname)
+{
+  group_timer_off(group);
+
+  if (PIM_DEBUG_IGMP_EVENTS) {
+    char group_str[100];
+    pim_inet4_dump("<group?>", group->group_addr, group_str, sizeof(group_str));
+    zlog_debug("Scheduling %ld.%03ld sec TIMER event for group %s on %s",
+	       interval_msec / 1000,
+	       interval_msec % 1000,
+	       group_str, ifname);
+  }
+
+  /*
+    RFC 3376: 6.2.2. Definition of Group Timers
+
+    The group timer is only used when a group is in EXCLUDE mode and
+    it represents the time for the *filter-mode* of the group to
+    expire and switch to INCLUDE mode.
+  */
+  zassert(group->group_filtermode_isexcl);
+
+  THREAD_TIMER_MSEC_ON(master, group->t_group_timer,
+		       igmp_group_timer,
+		       group, interval_msec);
+}
+
+static struct igmp_group *find_group_by_addr(struct igmp_sock *igmp,
+					     struct in_addr group_addr)
+{
+  struct igmp_group *group;
+  struct listnode   *node;
+
+  for (ALL_LIST_ELEMENTS_RO(igmp->igmp_group_list, node, group))
+    if (group_addr.s_addr == group->group_addr.s_addr)
+      return group;
+
+  return 0;
+}
+
+struct igmp_group *igmp_add_group_by_addr(struct igmp_sock *igmp,
+					  struct in_addr group_addr,
+					  const char *ifname)
+{
+  struct igmp_group *group;
+
+  group = find_group_by_addr(igmp, group_addr);
+  if (group) {
+    return group;
+  }
+
+  /*
+    Non-existant group is created as INCLUDE {empty}:
+
+    RFC 3376 - 5.1. Action on Change of Interface State
+
+    If no interface state existed for that multicast address before
+    the change (i.e., the change consisted of creating a new
+    per-interface record), or if no state exists after the change
+    (i.e., the change consisted of deleting a per-interface record),
+    then the "non-existent" state is considered to have a filter mode
+    of INCLUDE and an empty source list.
+  */
+
+  group = XMALLOC(MTYPE_PIM_IGMP_GROUP, sizeof(*group));
+  if (!group) {
+    zlog_warn("%s %s: XMALLOC() failure",
+	      __FILE__, __PRETTY_FUNCTION__);
+    return 0; /* error, not found, could not create */
+  }
+
+  group->group_source_list = list_new();
+  if (!group->group_source_list) {
+    zlog_warn("%s %s: list_new() failure",
+	      __FILE__, __PRETTY_FUNCTION__);
+    XFREE(MTYPE_PIM_IGMP_GROUP, group); /* discard group */
+    return 0; /* error, not found, could not initialize */
+  }
+  group->group_source_list->del = (void (*)(void *)) igmp_source_free;
+
+  group->t_group_timer                         = 0;
+  group->t_group_query_retransmit_timer        = 0;
+  group->group_specific_query_retransmit_count = 0;
+  group->group_addr                            = group_addr;
+  group->group_igmp_sock                       = igmp;
+  group->last_igmp_v1_report_dsec              = -1;
+  group->last_igmp_v2_report_dsec              = -1;
+  group->group_creation                        = pim_time_monotonic_sec();
+
+  /* initialize new group as INCLUDE {empty} */
+  group->group_filtermode_isexcl = 0; /* 0=INCLUDE, 1=EXCLUDE */
+
+  listnode_add(igmp->igmp_group_list, group);
+
+  if (PIM_DEBUG_IGMP_TRACE) {
+    char group_str[100];
+    pim_inet4_dump("<group?>", group->group_addr, group_str, sizeof(group_str));
+    zlog_debug("Creating new IGMP group %s on socket %d interface %s",
+	       group_str, group->group_igmp_sock->fd, ifname);
+  }
+
+  /*
+    RFC 3376: 6.2.2. Definition of Group Timers
+
+    The group timer is only used when a group is in EXCLUDE mode and
+    it represents the time for the *filter-mode* of the group to
+    expire and switch to INCLUDE mode.
+  */
+  zassert(!group->group_filtermode_isexcl); /* INCLUDE mode */
+  zassert(!group->t_group_timer); /* group timer == 0 */
+
+  /* Any source (*,G) is forwarded only if mode is EXCLUDE {empty} */
+  igmp_anysource_forward_stop(group);
+
+  return group;
+}