[mirror_frr.git] / pimd / pim_ifchannel.c

/*
  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
*/

#include <zebra.h>

#include "linklist.h"
#include "thread.h"
#include "memory.h"
#include "if.h"
#include "vrf.h"
#include "hash.h"
#include "jhash.h"

#include "pimd.h"
#include "pim_str.h"
#include "pim_iface.h"
#include "pim_ifchannel.h"
#include "pim_zebra.h"
#include "pim_time.h"
#include "pim_msg.h"
#include "pim_pim.h"
#include "pim_join.h"
#include "pim_rpf.h"
#include "pim_macro.h"
#include "pim_oil.h"
#include "pim_upstream.h"
#include "pim_ssm.h"

int
pim_ifchannel_compare (struct pim_ifchannel *ch1, struct pim_ifchannel *ch2)
{
  struct pim_interface *pim_ifp1;
  struct pim_interface *pim_ifp2;

  if (ntohl(ch1->sg.grp.s_addr) < ntohl(ch2->sg.grp.s_addr))
    return -1;

  if (ntohl(ch1->sg.grp.s_addr) > ntohl(ch2->sg.grp.s_addr))
    return 1;

  if (ntohl(ch1->sg.src.s_addr) < ntohl(ch2->sg.src.s_addr))
    return -1;

  if (ntohl(ch1->sg.src.s_addr) > ntohl(ch2->sg.src.s_addr))
    return 1;

  pim_ifp1 = ch1->interface->info;
  pim_ifp2 = ch2->interface->info;
  if (ntohl(pim_ifp1->primary_address.s_addr) < ntohl(pim_ifp2->primary_address.s_addr))
    return -1;

  if (ntohl(pim_ifp1->primary_address.s_addr) > ntohl(pim_ifp2->primary_address.s_addr))
    return 1;

  if (pim_ifp1->mroute_vif_index < pim_ifp2->mroute_vif_index)
    return -1;

  if (pim_ifp1->mroute_vif_index > pim_ifp2->mroute_vif_index)
    return 1;

  return 0;
}

/*
 * A (*,G) or a (*,*) is going away
 * remove the parent pointer from
 * those pointing at us
 */
static void
pim_ifchannel_remove_children (struct pim_ifchannel *ch)
{
  struct pim_ifchannel *child;

  if (!ch->sources)
    return;

  while (!list_isempty (ch->sources))
    {
      child = listnode_head (ch->sources);
      child->parent = NULL;
      listnode_delete (ch->sources, child);
    }
}

/*
 * A (*,G) or a (*,*) is being created
 * find all the children that would point
 * at us.
 */
static void
pim_ifchannel_find_new_children (struct pim_ifchannel *ch)
{
  struct pim_interface *pim_ifp = ch->interface->info;
  struct pim_ifchannel *child;
  struct listnode *ch_node;

  // Basic Sanity that we are not being silly
  if ((ch->sg.src.s_addr != INADDR_ANY) &&
      (ch->sg.grp.s_addr != INADDR_ANY))
    return;

  if ((ch->sg.src.s_addr == INADDR_ANY) &&
      (ch->sg.grp.s_addr == INADDR_ANY))
    return;

  for (ALL_LIST_ELEMENTS_RO (pim_ifp->pim_ifchannel_list, ch_node, child))
    {
      if ((ch->sg.grp.s_addr != INADDR_ANY) &&
	  (child->sg.grp.s_addr == ch->sg.grp.s_addr) &&
	  (child != ch))
	{
	  child->parent = ch;
	  listnode_add_sort (ch->sources, child);
	}
    }
}

void pim_ifchannel_free(struct pim_ifchannel *ch)
{
  XFREE(MTYPE_PIM_IFCHANNEL, ch);
}

void pim_ifchannel_delete(struct pim_ifchannel *ch)
{
  struct pim_interface *pim_ifp;

  pim_ifp = ch->interface->info;

  if (ch->upstream->channel_oil)
    {
      uint32_t mask = PIM_OIF_FLAG_PROTO_PIM;
      if (ch->upstream->flags & PIM_UPSTREAM_FLAG_MASK_SRC_IGMP)
        mask = PIM_OIF_FLAG_PROTO_IGMP;

      pim_channel_del_oif (ch->upstream->channel_oil, ch->interface, mask);
      /*
       * Do we have any S,G's that are inheriting?
       * Nuke from on high too.
       */
      if (ch->upstream->sources)
	{
	  struct pim_upstream *child;
	  struct listnode *up_node;

	  for (ALL_LIST_ELEMENTS_RO (ch->upstream->sources, up_node, child))
            pim_channel_del_oif (child->channel_oil, ch->interface, PIM_OIF_FLAG_PROTO_STAR);
	}
    }

  /*
   * When this channel is removed
   * we need to find all our children
   * and make sure our pointers are fixed
   */
  pim_ifchannel_remove_children (ch);

  if (ch->sources)
    list_delete (ch->sources);

  if (ch->ifjoin_state != PIM_IFJOIN_NOINFO) {
    pim_upstream_update_join_desired(ch->upstream);
  }

  pim_upstream_del(ch->upstream, __PRETTY_FUNCTION__);
  ch->upstream = NULL;

  THREAD_OFF(ch->t_ifjoin_expiry_timer);
  THREAD_OFF(ch->t_ifjoin_prune_pending_timer);
  THREAD_OFF(ch->t_ifassert_timer);

  if (ch->parent)
    {
      listnode_delete (ch->parent->sources, ch);
      ch->parent = NULL;
    }
  /*
    notice that listnode_delete() can't be moved
    into pim_ifchannel_free() because the later is
    called by list_delete_all_node()
  */
  listnode_delete(pim_ifp->pim_ifchannel_list, ch);
  hash_release(pim_ifp->pim_ifchannel_hash, ch);
  listnode_delete(pim_ifchannel_list, ch);

  pim_ifchannel_free(ch);
}

void
pim_ifchannel_delete_all (struct interface *ifp)
{
  struct pim_interface *pim_ifp;
  struct listnode *ifchannel_node;
  struct listnode *ifchannel_nextnode;
  struct pim_ifchannel *ifchannel;

  pim_ifp = ifp->info;
  if (!pim_ifp)
    return;

  for (ALL_LIST_ELEMENTS (pim_ifp->pim_ifchannel_list, ifchannel_node,
			  ifchannel_nextnode, ifchannel))
    {
      pim_ifchannel_delete (ifchannel);
    }
}
   
static void delete_on_noinfo(struct pim_ifchannel *ch)
{
  if (ch->local_ifmembership == PIM_IFMEMBERSHIP_NOINFO &&
      ch->ifjoin_state == PIM_IFJOIN_NOINFO &&
      ch->t_ifjoin_expiry_timer == NULL)
    pim_ifchannel_delete(ch);

}

void pim_ifchannel_ifjoin_switch(const char *caller,
				 struct pim_ifchannel *ch,
				 enum pim_ifjoin_state new_state)
{
  enum pim_ifjoin_state old_state = ch->ifjoin_state;

  if (PIM_DEBUG_PIM_EVENTS)
    zlog_debug ("PIM_IFCHANNEL(%s): %s is switching from %s to %s",
		ch->interface->name,
		ch->sg_str,
		pim_ifchannel_ifjoin_name (ch->ifjoin_state, ch->flags),
		pim_ifchannel_ifjoin_name (new_state, 0));


  if (old_state == new_state) {
    if (PIM_DEBUG_PIM_EVENTS) {
      zlog_debug("%s calledby %s: non-transition on state %d (%s)",
		 __PRETTY_FUNCTION__, caller, new_state,
		 pim_ifchannel_ifjoin_name(new_state, 0));
    }
    return;
  }

  ch->ifjoin_state = new_state;

  if (ch->sg.src.s_addr == INADDR_ANY)
    {
      struct pim_upstream *up = ch->upstream;
      struct pim_upstream *child;
      struct listnode *up_node;

      if (up)
	{
	  if (ch->ifjoin_state == PIM_IFJOIN_NOINFO)
	    {
	      for (ALL_LIST_ELEMENTS_RO (up->sources, up_node, child))
		{
		  struct channel_oil *c_oil = child->channel_oil;
		  struct pim_interface *pim_ifp = ch->interface->info;

		  if (PIM_DEBUG_PIM_TRACE)
		    zlog_debug("%s %s: Prune(S,G)=%s from %s",
			       __FILE__, __PRETTY_FUNCTION__,
			       child->sg_str, up->sg_str);
		  if (!c_oil)
		    continue;

		  if (!pim_upstream_evaluate_join_desired (child))
                    {
                      pim_channel_del_oif (c_oil, ch->interface, PIM_OIF_FLAG_PROTO_STAR);
                      pim_upstream_update_join_desired (child);
                    }

		  /*
		   * If the S,G has no if channel and the c_oil still
		   * has output here then the *,G was supplying the implied
		   * if channel.  So remove it.
                   * I think this is dead code now. is it?
		   */
		  if (!ch && c_oil->oil.mfcc_ttls[pim_ifp->mroute_vif_index])
                    pim_channel_del_oif (c_oil, ch->interface, PIM_OIF_FLAG_PROTO_STAR);
		}
	    }
	  if (ch->ifjoin_state == PIM_IFJOIN_JOIN)
	    {
	      for (ALL_LIST_ELEMENTS_RO (up->sources, up_node, child))
		{
		  if (PIM_DEBUG_PIM_TRACE)
		    zlog_debug("%s %s: Join(S,G)=%s from %s",
			       __FILE__, __PRETTY_FUNCTION__,
			       child->sg_str, up->sg_str);

		  if (pim_upstream_evaluate_join_desired (child))
		    {
                      pim_channel_add_oif (child->channel_oil, ch->interface, PIM_OIF_FLAG_PROTO_STAR);
                      pim_upstream_update_join_desired (child);
		    }
		}
	    }
	}
    }
  /* Transition to/from NOINFO ? */
  if ((old_state == PIM_IFJOIN_NOINFO) ||
      (new_state == PIM_IFJOIN_NOINFO)) {

    if (PIM_DEBUG_PIM_EVENTS) {
      zlog_debug("PIM_IFCHANNEL_%s: (S,G)=%s on interface %s",
		 ((new_state == PIM_IFJOIN_NOINFO) ? "DOWN" : "UP"),
		 ch->sg_str, ch->interface->name);
    }

    /*
      Record uptime of state transition to/from NOINFO
    */
    ch->ifjoin_creation = pim_time_monotonic_sec();

    pim_upstream_update_join_desired(ch->upstream);
    pim_ifchannel_update_could_assert(ch);
    pim_ifchannel_update_assert_tracking_desired(ch);
  }
}

const char *pim_ifchannel_ifjoin_name(enum pim_ifjoin_state ifjoin_state,
                                      int flags)
{
  switch (ifjoin_state) {
  case PIM_IFJOIN_NOINFO:
     if (PIM_IF_FLAG_TEST_S_G_RPT(flags))
       return "SGRpt";
     else
       return "NOINFO";
     break;
  case PIM_IFJOIN_JOIN:
     return "JOIN";
     break;
  case PIM_IFJOIN_PRUNE:
     return "PRUNE";
     break;
  case PIM_IFJOIN_PRUNE_PENDING:
     return "PRUNEP";
     break;
  case PIM_IFJOIN_PRUNE_TMP:
     return "PRUNET";
     break;
  case PIM_IFJOIN_PRUNE_PENDING_TMP:
     return "PRUNEPT";
     break;
  }

  return "ifjoin_bad_state";
}

const char *pim_ifchannel_ifassert_name(enum pim_ifassert_state ifassert_state)
{
  switch (ifassert_state) {
  case PIM_IFASSERT_NOINFO:      return "NOINFO";
  case PIM_IFASSERT_I_AM_WINNER: return "WINNER";
  case PIM_IFASSERT_I_AM_LOSER:  return "LOSER";
  }

  return "ifassert_bad_state";
}

/*
  RFC 4601: 4.6.5.  Assert State Macros

  AssertWinner(S,G,I) defaults to NULL and AssertWinnerMetric(S,G,I)
  defaults to Infinity when in the NoInfo state.
*/
void reset_ifassert_state(struct pim_ifchannel *ch)
{
  THREAD_OFF(ch->t_ifassert_timer);

  pim_ifassert_winner_set(ch,
			  PIM_IFASSERT_NOINFO,
			  qpim_inaddr_any,
			  qpim_infinite_assert_metric);
}

struct pim_ifchannel *pim_ifchannel_find(struct interface *ifp,
					 struct prefix_sg *sg)
{
  struct pim_interface *pim_ifp;
  struct pim_ifchannel *ch;
  struct pim_ifchannel lookup;

  pim_ifp = ifp->info;

  if (!pim_ifp) {
    zlog_warn("%s: (S,G)=%s: multicast not enabled on interface %s",
	      __PRETTY_FUNCTION__,
	      pim_str_sg_dump (sg),
	      ifp->name);
    return NULL;
  }

  lookup.sg = *sg;
  ch = hash_lookup (pim_ifp->pim_ifchannel_hash, &lookup);

  return ch;
}

static void ifmembership_set(struct pim_ifchannel *ch,
			     enum pim_ifmembership membership)
{
  if (ch->local_ifmembership == membership)
    return;

  if (PIM_DEBUG_PIM_EVENTS) {
    zlog_debug("%s: (S,G)=%s membership now is %s on interface %s",
	       __PRETTY_FUNCTION__,
	       ch->sg_str,
	       membership == PIM_IFMEMBERSHIP_INCLUDE ? "INCLUDE" : "NOINFO",
	       ch->interface->name);
  }
  
  ch->local_ifmembership = membership;

  pim_upstream_update_join_desired(ch->upstream);
  pim_ifchannel_update_could_assert(ch);
  pim_ifchannel_update_assert_tracking_desired(ch);
}


void pim_ifchannel_membership_clear(struct interface *ifp)
{
  struct pim_interface *pim_ifp;
  struct listnode      *ch_node;
  struct pim_ifchannel *ch;

  pim_ifp = ifp->info;
  zassert(pim_ifp);

  for (ALL_LIST_ELEMENTS_RO(pim_ifp->pim_ifchannel_list, ch_node, ch)) {
    ifmembership_set(ch, PIM_IFMEMBERSHIP_NOINFO);
  }
}

void pim_ifchannel_delete_on_noinfo(struct interface *ifp)
{
  struct pim_interface *pim_ifp;
  struct listnode      *node;
  struct listnode      *next_node;
  struct pim_ifchannel *ch;

  pim_ifp = ifp->info;
  zassert(pim_ifp);

  for (ALL_LIST_ELEMENTS(pim_ifp->pim_ifchannel_list, node, next_node, ch)) {
    delete_on_noinfo(ch);
  }
}

/*
 * For a given Interface, if we are given a S,G
 * Find the *,G (If we have it).
 * If we are passed a *,G, find the *,* ifchannel
 * if we have it.
 */
static struct pim_ifchannel *
pim_ifchannel_find_parent (struct pim_ifchannel *ch)
{
  struct prefix_sg parent_sg = ch->sg;
  struct pim_ifchannel *parent = NULL;

  // (S,G)
  if ((parent_sg.src.s_addr != INADDR_ANY) &&
      (parent_sg.grp.s_addr != INADDR_ANY))
    {
      parent_sg.src.s_addr = INADDR_ANY;
      parent = pim_ifchannel_find (ch->interface, &parent_sg);

      if (parent)
	listnode_add (parent->sources, ch);
      return parent;
    }

  return NULL;
}

struct pim_ifchannel *
pim_ifchannel_add(struct interface *ifp,
		  struct prefix_sg *sg, int flags)
{
  struct pim_interface *pim_ifp;
  struct pim_ifchannel *ch;
  struct pim_upstream *up;

  ch = pim_ifchannel_find(ifp, sg);
  if (ch)
    return ch;

  pim_ifp = ifp->info;

  up = pim_upstream_add(sg, NULL, flags, __PRETTY_FUNCTION__);
  if (!up) {
    zlog_err("%s: could not attach upstream (S,G)=%s on interface %s",
	     __PRETTY_FUNCTION__,
	     pim_str_sg_dump (sg), ifp->name);
    return NULL;
  }

  ch = XCALLOC(MTYPE_PIM_IFCHANNEL, sizeof(*ch));
  if (!ch) {
    zlog_warn("%s: pim_ifchannel_new() failure for (S,G)=%s on interface %s",
	      __PRETTY_FUNCTION__,
	      up->sg_str, ifp->name);

    pim_upstream_del (up, __PRETTY_FUNCTION__);
    return NULL;
  }

  ch->flags                        = 0;
  ch->upstream                     = up;
  ch->interface                    = ifp;
  ch->sg                           = *sg;
  pim_str_sg_set (sg, ch->sg_str);
  ch->parent                       = pim_ifchannel_find_parent (ch);
  if (ch->sg.src.s_addr == INADDR_ANY)
    {
      ch->sources = list_new ();
      ch->sources->cmp = (int (*)(void *, void *))pim_ifchannel_compare;
    }
  else
    ch->sources = NULL;

  pim_ifchannel_find_new_children (ch);
  ch->local_ifmembership           = PIM_IFMEMBERSHIP_NOINFO;

  ch->ifjoin_state                 = PIM_IFJOIN_NOINFO;
  ch->t_ifjoin_expiry_timer        = NULL;
  ch->t_ifjoin_prune_pending_timer = NULL;
  ch->ifjoin_creation              = 0;

  ch->ifassert_my_metric = pim_macro_ch_my_assert_metric_eval(ch);
  ch->ifassert_winner_metric = pim_macro_ch_my_assert_metric_eval (ch);

  ch->ifassert_winner.s_addr = 0;

  /* Assert state */
  ch->t_ifassert_timer   = NULL;
  ch->ifassert_state = PIM_IFASSERT_NOINFO;
  reset_ifassert_state(ch);
  if (pim_macro_ch_could_assert_eval(ch))
    PIM_IF_FLAG_SET_COULD_ASSERT(ch->flags);
  else
    PIM_IF_FLAG_UNSET_COULD_ASSERT(ch->flags);

  if (pim_macro_assert_tracking_desired_eval(ch))
    PIM_IF_FLAG_SET_ASSERT_TRACKING_DESIRED(ch->flags);
  else
    PIM_IF_FLAG_UNSET_ASSERT_TRACKING_DESIRED(ch->flags);

  /* Attach to list */
  listnode_add_sort(pim_ifp->pim_ifchannel_list, ch);
  ch = hash_get (pim_ifp->pim_ifchannel_hash, ch, hash_alloc_intern);
  listnode_add_sort(pim_ifchannel_list, ch);

  return ch;
}

static void ifjoin_to_noinfo(struct pim_ifchannel *ch)
{
  pim_forward_stop(ch);
  pim_ifchannel_ifjoin_switch(__PRETTY_FUNCTION__, ch, PIM_IFJOIN_NOINFO);
  delete_on_noinfo(ch);
}

static int on_ifjoin_expiry_timer(struct thread *t)
{
  struct pim_ifchannel *ch;

  ch = THREAD_ARG(t);

  ch->t_ifjoin_expiry_timer = NULL;

  ifjoin_to_noinfo(ch);
  /* ch may have been deleted */

  return 0;
}

static int on_ifjoin_prune_pending_timer(struct thread *t)
{
  struct pim_ifchannel *ch;
  int send_prune_echo; /* boolean */
  struct interface *ifp;
  struct pim_interface *pim_ifp;

  ch = THREAD_ARG(t);

  ch->t_ifjoin_prune_pending_timer = NULL;

  if (ch->ifjoin_state == PIM_IFJOIN_PRUNE_PENDING)
    {
      /* Send PruneEcho(S,G) ? */
      ifp = ch->interface;
      pim_ifp = ifp->info;
      send_prune_echo = (listcount(pim_ifp->pim_neighbor_list) > 1);

      ifjoin_to_noinfo(ch);
      /* from here ch may have been deleted */

      if (send_prune_echo)
        {
          struct pim_rpf rpf;

          rpf.source_nexthop.interface = ifp;
          rpf.rpf_addr.u.prefix4 = pim_ifp->primary_address;
          pim_jp_agg_single_upstream_send(&rpf, ch->upstream, 0);
        }
    }
  else
    {
      zlog_warn("%s: IFCHANNEL%s Prune Pending Timer Popped while in %s state",
		__PRETTY_FUNCTION__, pim_str_sg_dump (&ch->sg),
		pim_ifchannel_ifjoin_name (ch->ifjoin_state, ch->flags));
    }

  return 0;
}

static void check_recv_upstream(int is_join,
				struct interface *recv_ifp,
				struct in_addr upstream,
				struct prefix_sg *sg,
				uint8_t source_flags,
				int holdtime)
{
  struct pim_upstream *up;

  /* Upstream (S,G) in Joined state ? */
  up = pim_upstream_find(sg);
  if (!up)
    return;
  if (up->join_state != PIM_UPSTREAM_JOINED)
    return;

  /* Upstream (S,G) in Joined state */

  if (pim_rpf_addr_is_inaddr_any(&up->rpf)) {
    /* RPF'(S,G) not found */
    zlog_warn("%s %s: RPF'%s not found",
	      __FILE__, __PRETTY_FUNCTION__, 
	      up->sg_str);
    return;
  }

  /* upstream directed to RPF'(S,G) ? */
  if (upstream.s_addr != up->rpf.rpf_addr.u.prefix4.s_addr) {
    char up_str[INET_ADDRSTRLEN];
    char rpf_str[PREFIX_STRLEN];
    pim_inet4_dump("<up?>", upstream, up_str, sizeof(up_str));
    pim_addr_dump("<rpf?>", &up->rpf.rpf_addr, rpf_str, sizeof(rpf_str));
    zlog_warn("%s %s: (S,G)=%s upstream=%s not directed to RPF'(S,G)=%s on interface %s",
	      __FILE__, __PRETTY_FUNCTION__, 
	      up->sg_str,
	      up_str, rpf_str, recv_ifp->name);
    return;
  }
  /* upstream directed to RPF'(S,G) */

  if (is_join) {
    /* Join(S,G) to RPF'(S,G) */
    pim_upstream_join_suppress(up, up->rpf.rpf_addr.u.prefix4, holdtime);
    return;
  }

  /* Prune to RPF'(S,G) */

  if (source_flags & PIM_RPT_BIT_MASK) {
    if (source_flags & PIM_WILDCARD_BIT_MASK) {
      /* Prune(*,G) to RPF'(S,G) */
      pim_upstream_join_timer_decrease_to_t_override("Prune(*,G)", up);
      return;
    }

    /* Prune(S,G,rpt) to RPF'(S,G) */
    pim_upstream_join_timer_decrease_to_t_override("Prune(S,G,rpt)", up);
    return;
  }

  /* Prune(S,G) to RPF'(S,G) */
  pim_upstream_join_timer_decrease_to_t_override("Prune(S,G)", up);
}

static int
nonlocal_upstream(int is_join,
                  struct interface *recv_ifp,
                  struct in_addr upstream,
                  struct prefix_sg *sg,
                  uint8_t source_flags,
                  uint16_t holdtime)
{
  struct pim_interface *recv_pim_ifp;
  int is_local; /* boolean */

  recv_pim_ifp = recv_ifp->info;
  zassert(recv_pim_ifp);

  is_local = (upstream.s_addr == recv_pim_ifp->primary_address.s_addr);

  if (is_local)
    return 0;

  if (PIM_DEBUG_PIM_TRACE_DETAIL) {
    char up_str[INET_ADDRSTRLEN];
    pim_inet4_dump("<upstream?>", upstream, up_str, sizeof(up_str));
    zlog_warn("%s: recv %s (S,G)=%s to non-local upstream=%s on %s",
              __PRETTY_FUNCTION__,
              is_join ? "join" : "prune",
              pim_str_sg_dump (sg),
              up_str, recv_ifp->name);
  }

  /*
   * Since recv upstream addr was not directed to our primary
   * address, check if we should react to it in any way.
   */
  check_recv_upstream(is_join, recv_ifp, upstream, sg,
                      source_flags, holdtime);

  return 1; /* non-local */
}

void pim_ifchannel_join_add(struct interface *ifp,
			    struct in_addr neigh_addr,
			    struct in_addr upstream,
			    struct prefix_sg *sg,
			    uint8_t source_flags,
			    uint16_t holdtime)
{
  struct pim_interface *pim_ifp;
  struct pim_ifchannel *ch;

  if (nonlocal_upstream(1 /* join */, ifp, upstream,
			sg, source_flags, holdtime)) {
    return;
  }

  ch = pim_ifchannel_add(ifp, sg, PIM_UPSTREAM_FLAG_MASK_SRC_PIM);
  if (!ch)
    return;

  /*
    RFC 4601: 4.6.1.  (S,G) Assert Message State Machine

    Transitions from "I am Assert Loser" State

    Receive Join(S,G) on Interface I

    We receive a Join(S,G) that has the Upstream Neighbor Address
    field set to my primary IP address on interface I.  The action is
    to transition to NoInfo state, delete this (S,G) assert state
    (Actions A5 below), and allow the normal PIM Join/Prune mechanisms
    to operate.

    Notice: The nonlocal_upstream() test above ensures the upstream
    address of the join message is our primary address.
   */
  if (ch->ifassert_state == PIM_IFASSERT_I_AM_LOSER) {
    char neigh_str[INET_ADDRSTRLEN];
    pim_inet4_dump("<neigh?>", neigh_addr, neigh_str, sizeof(neigh_str));
    zlog_warn("%s: Assert Loser recv Join%s from %s on %s",
	      __PRETTY_FUNCTION__,
	      ch->sg_str, neigh_str, ifp->name);

    assert_action_a5(ch);
  }

  pim_ifp = ifp->info;
  zassert(pim_ifp);

  switch (ch->ifjoin_state) {
  case PIM_IFJOIN_NOINFO:
    pim_ifchannel_ifjoin_switch(__PRETTY_FUNCTION__, ch, PIM_IFJOIN_JOIN);
    if (pim_macro_chisin_oiflist(ch)) {
      pim_upstream_inherited_olist (ch->upstream);
      pim_forward_start(ch);
    }
    break;
  case PIM_IFJOIN_JOIN:
    zassert(!ch->t_ifjoin_prune_pending_timer);

    /*
      In the JOIN state ch->t_ifjoin_expiry_timer may be NULL due to a
      previously received join message with holdtime=0xFFFF.
     */
    if (ch->t_ifjoin_expiry_timer) {
      unsigned long remain =
	thread_timer_remain_second(ch->t_ifjoin_expiry_timer);
      if (remain > holdtime) {
	/*
	  RFC 4601: 4.5.3.  Receiving (S,G) Join/Prune Messages

	  Transitions from Join State

          The (S,G) downstream state machine on interface I remains in
          Join state, and the Expiry Timer (ET) is restarted, set to
          maximum of its current value and the HoldTime from the
          triggering Join/Prune message.

	  Conclusion: Do not change the ET if the current value is
	  higher than the received join holdtime.
	 */
	return;
      }
    }
    THREAD_OFF(ch->t_ifjoin_expiry_timer);
    break;
  case PIM_IFJOIN_PRUNE:
    if (source_flags & PIM_ENCODE_RPT_BIT)
      pim_ifchannel_ifjoin_switch(__PRETTY_FUNCTION__, ch, PIM_IFJOIN_NOINFO);
    break;
  case PIM_IFJOIN_PRUNE_PENDING:
    THREAD_OFF(ch->t_ifjoin_prune_pending_timer);
    if (source_flags & PIM_ENCODE_RPT_BIT)
      {
	THREAD_OFF(ch->t_ifjoin_expiry_timer);
	pim_ifchannel_ifjoin_switch(__PRETTY_FUNCTION__, ch, PIM_IFJOIN_NOINFO);
      }
    else
      pim_ifchannel_ifjoin_switch(__PRETTY_FUNCTION__, ch, PIM_IFJOIN_JOIN);
    break;
  case PIM_IFJOIN_PRUNE_TMP:
    break;
  case PIM_IFJOIN_PRUNE_PENDING_TMP:
    break;
  }

  if (holdtime != 0xFFFF) {
    THREAD_TIMER_ON(master, ch->t_ifjoin_expiry_timer,
		    on_ifjoin_expiry_timer,
		    ch, holdtime);
  }
}

void pim_ifchannel_prune(struct interface *ifp,
			 struct in_addr upstream,
			 struct prefix_sg *sg,
			 uint8_t source_flags,
			 uint16_t holdtime)
{
  struct pim_ifchannel *ch;
  struct pim_interface *pim_ifp;
  int jp_override_interval_msec;

  if (nonlocal_upstream(0 /* prune */, ifp, upstream,
			sg, source_flags, holdtime)) {
    return;
  }

  ch = pim_ifchannel_find (ifp, sg);
  if (!ch && !(source_flags & PIM_ENCODE_RPT_BIT))
    {
      if (PIM_DEBUG_TRACE)
	zlog_debug ("%s: Received prune with no relevant ifchannel %s(%s) state: %d",
		    __PRETTY_FUNCTION__, ifp->name, pim_str_sg_dump (sg), source_flags);
      return;
    }

  ch = pim_ifchannel_add(ifp, sg, PIM_UPSTREAM_FLAG_MASK_SRC_PIM);
  if (!ch)
    return;

  pim_ifp = ifp->info;

  switch (ch->ifjoin_state) {
  case PIM_IFJOIN_NOINFO:
    if (source_flags & PIM_ENCODE_RPT_BIT)
      {
	PIM_IF_FLAG_SET_S_G_RPT(ch->flags);
	ch->ifjoin_state = PIM_IFJOIN_PRUNE_PENDING;
        if (listcount(pim_ifp->pim_neighbor_list) > 1)
          jp_override_interval_msec = pim_if_jp_override_interval_msec(ifp);
        else
          jp_override_interval_msec = 0; /* schedule to expire immediately */
          /* If we called ifjoin_prune() directly instead, care should
             be taken not to use "ch" afterwards since it would be
             deleted. */

	THREAD_OFF(ch->t_ifjoin_prune_pending_timer);
	THREAD_OFF(ch->t_ifjoin_expiry_timer);
	THREAD_TIMER_MSEC_ON(master, ch->t_ifjoin_prune_pending_timer,
			     on_ifjoin_prune_pending_timer,
			     ch, jp_override_interval_msec);
	THREAD_TIMER_ON(master, ch->t_ifjoin_expiry_timer,
			on_ifjoin_expiry_timer,
			ch, holdtime);
        pim_upstream_update_join_desired(ch->upstream);
      }
    break;
  case PIM_IFJOIN_PRUNE_PENDING:
    /* nothing to do */
    break;
  case PIM_IFJOIN_JOIN:
    THREAD_OFF(ch->t_ifjoin_expiry_timer);

    pim_ifchannel_ifjoin_switch(__PRETTY_FUNCTION__, ch, PIM_IFJOIN_PRUNE_PENDING);

    if (listcount(pim_ifp->pim_neighbor_list) > 1)
      jp_override_interval_msec = pim_if_jp_override_interval_msec(ifp);
    else
      jp_override_interval_msec = 0; /* schedule to expire immediately */
      /* If we called ifjoin_prune() directly instead, care should
	 be taken not to use "ch" afterwards since it would be
	 deleted. */
    THREAD_OFF(ch->t_ifjoin_prune_pending_timer);
    THREAD_TIMER_MSEC_ON(master, ch->t_ifjoin_prune_pending_timer,
			 on_ifjoin_prune_pending_timer,
			 ch, jp_override_interval_msec);
    break;
  case PIM_IFJOIN_PRUNE:
    if (source_flags & PIM_ENCODE_RPT_BIT)
      {
	THREAD_OFF(ch->t_ifjoin_prune_pending_timer);
	THREAD_TIMER_ON(master, ch->t_ifjoin_expiry_timer,
			on_ifjoin_expiry_timer,
			ch, holdtime);
      }
    break;
  case PIM_IFJOIN_PRUNE_TMP:
    if (source_flags & PIM_ENCODE_RPT_BIT)
      {
	ch->ifjoin_state = PIM_IFJOIN_PRUNE;
	THREAD_OFF(ch->t_ifjoin_expiry_timer);
	THREAD_TIMER_ON(master, ch->t_ifjoin_expiry_timer,
			on_ifjoin_expiry_timer,
			ch, holdtime);
      }
    break;
  case PIM_IFJOIN_PRUNE_PENDING_TMP:
    if (source_flags & PIM_ENCODE_RPT_BIT)
      {
	ch->ifjoin_state = PIM_IFJOIN_PRUNE_PENDING;
	THREAD_OFF(ch->t_ifjoin_expiry_timer);
	THREAD_TIMER_ON(master, ch->t_ifjoin_expiry_timer,
			on_ifjoin_expiry_timer,
			ch, holdtime);
      }
    break;
  }
}

int
pim_ifchannel_local_membership_add(struct interface *ifp,
				   struct prefix_sg *sg)
{
  struct pim_ifchannel *ch;
  struct pim_interface *pim_ifp;

  /* PIM enabled on interface? */
  pim_ifp = ifp->info;
  if (!pim_ifp)
    return 0;
  if (!PIM_IF_TEST_PIM(pim_ifp->options))
    return 0;

  /* skip (*,G) ch creation if G is of type SSM */
  if (sg->src.s_addr == INADDR_ANY)
    {
      if (pim_is_grp_ssm (sg->grp))
        {
          if (PIM_DEBUG_PIM_EVENTS)
            zlog_debug("%s: local membership (S,G)=%s ignored as group is SSM",
                __PRETTY_FUNCTION__, pim_str_sg_dump (sg));
          return 1;
        }
    }

  ch = pim_ifchannel_add(ifp, sg, PIM_UPSTREAM_FLAG_MASK_SRC_IGMP);
  if (!ch) {
    return 0;
  }

  ifmembership_set(ch, PIM_IFMEMBERSHIP_INCLUDE);

  if (sg->src.s_addr == INADDR_ANY)
    {
      struct pim_upstream *up = pim_upstream_find (sg);
      struct pim_upstream *child;
      struct listnode *up_node;

      for (ALL_LIST_ELEMENTS_RO (up->sources, up_node, child))
        {
	  if (PIM_DEBUG_EVENTS)
	    zlog_debug("%s %s: IGMP (S,G)=%s(%s) from %s",
		       __FILE__, __PRETTY_FUNCTION__,
		       child->sg_str, ifp->name, up->sg_str);

	  if (pim_upstream_evaluate_join_desired_interface (child, ch))
	    {
	      pim_channel_add_oif (child->channel_oil, ifp, PIM_OIF_FLAG_PROTO_STAR);
	      pim_upstream_switch (child, PIM_UPSTREAM_JOINED);
	    }
        }
      if (pimg->spt_switchover != PIM_SPT_INFINITY)
        pim_channel_add_oif(up->channel_oil, pim_regiface, PIM_OIF_FLAG_PROTO_IGMP);
    }

  return 1;
}

void pim_ifchannel_local_membership_del(struct interface *ifp,
					struct prefix_sg *sg)
{
  struct pim_ifchannel *ch;
  struct pim_interface *pim_ifp;

  /* PIM enabled on interface? */
  pim_ifp = ifp->info;
  if (!pim_ifp)
    return;
  if (!PIM_IF_TEST_PIM(pim_ifp->options))
    return;

  ch = pim_ifchannel_find(ifp, sg);
  if (!ch)
    return;

  ifmembership_set(ch, PIM_IFMEMBERSHIP_NOINFO);

  if (sg->src.s_addr == INADDR_ANY)
    {
      struct pim_upstream *up = pim_upstream_find (sg);
      struct pim_upstream *child;
      struct listnode *up_node;

      for (ALL_LIST_ELEMENTS_RO (up->sources, up_node, child))
        {
	  struct channel_oil *c_oil = child->channel_oil;
	  struct pim_ifchannel *chchannel = pim_ifchannel_find (ifp, &child->sg);
	  struct pim_interface *pim_ifp = ifp->info;

	  if (PIM_DEBUG_EVENTS)
	    zlog_debug("%s %s: Prune(S,G)=%s(%s) from %s",
		       __FILE__, __PRETTY_FUNCTION__,
		       up->sg_str, ifp->name, child->sg_str);

	  if (c_oil && !pim_upstream_evaluate_join_desired_interface (child, ch))
            pim_channel_del_oif (c_oil, ifp, PIM_OIF_FLAG_PROTO_STAR);

	  /*
	   * If the S,G has no if channel and the c_oil still
	   * has output here then the *,G was supplying the implied
	   * if channel.  So remove it.
	   */
	  if (!chchannel && c_oil && c_oil->oil.mfcc_ttls[pim_ifp->mroute_vif_index])
            pim_channel_del_oif (c_oil, ifp, PIM_OIF_FLAG_PROTO_STAR);
        }
    }
  delete_on_noinfo(ch);
}

void pim_ifchannel_update_could_assert(struct pim_ifchannel *ch)
{
  int old_couldassert = PIM_FORCE_BOOLEAN(PIM_IF_FLAG_TEST_COULD_ASSERT(ch->flags));
  int new_couldassert = PIM_FORCE_BOOLEAN(pim_macro_ch_could_assert_eval(ch));

  if (new_couldassert == old_couldassert)
    return;

  if (PIM_DEBUG_PIM_EVENTS) {
    char src_str[INET_ADDRSTRLEN];
    char grp_str[INET_ADDRSTRLEN];
    pim_inet4_dump("<src?>", ch->sg.src, src_str, sizeof(src_str));
    pim_inet4_dump("<grp?>", ch->sg.grp, grp_str, sizeof(grp_str));
    zlog_debug("%s: CouldAssert(%s,%s,%s) changed from %d to %d",
	       __PRETTY_FUNCTION__,
	       src_str, grp_str, ch->interface->name,
	       old_couldassert, new_couldassert);
  }

  if (new_couldassert) {
    /* CouldAssert(S,G,I) switched from FALSE to TRUE */
    PIM_IF_FLAG_SET_COULD_ASSERT(ch->flags);
  }
  else {
    /* CouldAssert(S,G,I) switched from TRUE to FALSE */
    PIM_IF_FLAG_UNSET_COULD_ASSERT(ch->flags);

    if (ch->ifassert_state == PIM_IFASSERT_I_AM_WINNER) {
      assert_action_a4(ch);
    }
  }

  pim_ifchannel_update_my_assert_metric(ch);
}

/*
  my_assert_metric may be affected by:

  CouldAssert(S,G)
  pim_ifp->primary_address
  rpf->source_nexthop.mrib_metric_preference;
  rpf->source_nexthop.mrib_route_metric;
 */
void pim_ifchannel_update_my_assert_metric(struct pim_ifchannel *ch)
{
  struct pim_assert_metric my_metric_new = pim_macro_ch_my_assert_metric_eval(ch);

  if (pim_assert_metric_match(&my_metric_new, &ch->ifassert_my_metric))
      return;

  if (PIM_DEBUG_PIM_EVENTS) {
    char src_str[INET_ADDRSTRLEN];
    char grp_str[INET_ADDRSTRLEN];
    char old_addr_str[INET_ADDRSTRLEN];
    char new_addr_str[INET_ADDRSTRLEN];
    pim_inet4_dump("<src?>", ch->sg.src, src_str, sizeof(src_str));
    pim_inet4_dump("<grp?>", ch->sg.grp, grp_str, sizeof(grp_str));
    pim_inet4_dump("<old_addr?>", ch->ifassert_my_metric.ip_address, old_addr_str, sizeof(old_addr_str));
    pim_inet4_dump("<new_addr?>", my_metric_new.ip_address, new_addr_str, sizeof(new_addr_str));
    zlog_debug("%s: my_assert_metric(%s,%s,%s) changed from %u,%u,%u,%s to %u,%u,%u,%s",
	       __PRETTY_FUNCTION__,
	       src_str, grp_str, ch->interface->name,
	       ch->ifassert_my_metric.rpt_bit_flag,
	       ch->ifassert_my_metric.metric_preference,
	       ch->ifassert_my_metric.route_metric,
	       old_addr_str,
	       my_metric_new.rpt_bit_flag,
	       my_metric_new.metric_preference,
	       my_metric_new.route_metric,
	       new_addr_str);
  }

  ch->ifassert_my_metric = my_metric_new;

  if (pim_assert_metric_better(&ch->ifassert_my_metric,
			       &ch->ifassert_winner_metric)) {
    assert_action_a5(ch);
  }
}

void pim_ifchannel_update_assert_tracking_desired(struct pim_ifchannel *ch)
{
  int old_atd = PIM_FORCE_BOOLEAN(PIM_IF_FLAG_TEST_ASSERT_TRACKING_DESIRED(ch->flags));
  int new_atd = PIM_FORCE_BOOLEAN(pim_macro_assert_tracking_desired_eval(ch));

  if (new_atd == old_atd)
    return;

  if (PIM_DEBUG_PIM_EVENTS) {
    char src_str[INET_ADDRSTRLEN];
    char grp_str[INET_ADDRSTRLEN];
    pim_inet4_dump("<src?>", ch->sg.src, src_str, sizeof(src_str));
    pim_inet4_dump("<grp?>", ch->sg.grp, grp_str, sizeof(grp_str));
    zlog_debug("%s: AssertTrackingDesired(%s,%s,%s) changed from %d to %d",
	       __PRETTY_FUNCTION__,
	       src_str, grp_str, ch->interface->name,
	       old_atd, new_atd);
  }

  if (new_atd) {
    /* AssertTrackingDesired(S,G,I) switched from FALSE to TRUE */
    PIM_IF_FLAG_SET_ASSERT_TRACKING_DESIRED(ch->flags);
  }
  else {
    /* AssertTrackingDesired(S,G,I) switched from TRUE to FALSE */
    PIM_IF_FLAG_UNSET_ASSERT_TRACKING_DESIRED(ch->flags);

    if (ch->ifassert_state == PIM_IFASSERT_I_AM_LOSER) {
      assert_action_a5(ch);
    }
  }
}

/*
 * If we have a new pim interface, check to
 * see if any of the pre-existing channels have
 * their upstream out that way and turn on forwarding
 * for that ifchannel then.
 */
void
pim_ifchannel_scan_forward_start (struct interface *new_ifp)
{
  struct listnode *ifnode;
  struct interface *ifp;
  struct pim_interface *new_pim_ifp = new_ifp->info;

  for (ALL_LIST_ELEMENTS_RO (vrf_iflist (VRF_DEFAULT), ifnode, ifp))
    {
      struct pim_interface *loop_pim_ifp = ifp->info;
      struct listnode *ch_node;
      struct pim_ifchannel *ch;

      if (!loop_pim_ifp)
        continue;

      if (new_pim_ifp == loop_pim_ifp)
        continue;

      for (ALL_LIST_ELEMENTS_RO (loop_pim_ifp->pim_ifchannel_list, ch_node, ch))
        {
          if (ch->ifjoin_state == PIM_IFJOIN_JOIN)
            {
              struct pim_upstream *up = ch->upstream;
              if ((!up->channel_oil) &&
		  (up->rpf.source_nexthop.interface == new_ifp))
                pim_forward_start (ch);
            }
        }
    }
}

/*
 * Downstream per-interface (S,G,rpt) state machine
 * states that we need to move (S,G,rpt) items
 * into different states at the start of the
 * reception of a *,G join as well, when
 * we get End of Message
 */
void
pim_ifchannel_set_star_g_join_state (struct pim_ifchannel *ch, int eom)
{
  struct pim_ifchannel *child;
  struct listnode *ch_node;

  if (PIM_DEBUG_PIM_TRACE)
    zlog_debug ("%s: %s %s eom: %d", __PRETTY_FUNCTION__,
                pim_ifchannel_ifjoin_name(ch->ifjoin_state, ch->flags),
                ch->sg_str, eom);
  if (!ch->sources)
    return;

  for (ALL_LIST_ELEMENTS_RO (ch->sources, ch_node, child))
    {
      if (!PIM_IF_FLAG_TEST_S_G_RPT(child->flags))
        continue;

      switch (child->ifjoin_state)
	{
	case PIM_IFJOIN_NOINFO:
	case PIM_IFJOIN_JOIN:
	  break;
	case PIM_IFJOIN_PRUNE:
	  if (!eom)
	    child->ifjoin_state = PIM_IFJOIN_PRUNE_TMP;
	  break;
	case PIM_IFJOIN_PRUNE_PENDING:
	  if (!eom)
	    child->ifjoin_state = PIM_IFJOIN_PRUNE_PENDING_TMP;
	  break;
	case PIM_IFJOIN_PRUNE_TMP:
	case PIM_IFJOIN_PRUNE_PENDING_TMP:
	  if (eom)
	    child->ifjoin_state = PIM_IFJOIN_NOINFO;
	  break;
	}
    }
}

unsigned int
pim_ifchannel_hash_key (void *arg)
{
  struct pim_ifchannel *ch = (struct pim_ifchannel *)arg;

  return jhash_2words (ch->sg.src.s_addr, ch->sg.grp.s_addr, 0);
}

int
pim_ifchannel_equal (const void *arg1, const void *arg2)
{
  const struct pim_ifchannel *ch1 = (const struct pim_ifchannel *)arg1;
  const struct pim_ifchannel *ch2 = (const struct pim_ifchannel *)arg2;

  if ((ch1->sg.grp.s_addr == ch2->sg.grp.s_addr) &&
      (ch1->sg.src.s_addr == ch2->sg.src.s_addr))
    return 1;

  return 0;
}