path: root/pimd/pim_rpf.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 "if.h"

#include "log.h"
#include "prefix.h"
#include "memory.h"

#include "pimd.h"
#include "pim_rpf.h"
#include "pim_pim.h"
#include "pim_str.h"
#include "pim_iface.h"
#include "pim_zlookup.h"
#include "pim_ifchannel.h"
#include "pim_time.h"
#include "pim_nht.h"

static long long last_route_change_time = -1;
long long nexthop_lookups_avoided = 0;

static struct in_addr pim_rpf_find_rpf_addr (struct pim_upstream *up);

void
pim_rpf_set_refresh_time (void)
{
  last_route_change_time = pim_time_monotonic_usec();
  if (PIM_DEBUG_TRACE)
    zlog_debug ("%s: New last route change time: %lld",
		__PRETTY_FUNCTION__, last_route_change_time);
}

int pim_nexthop_lookup(struct pim_nexthop *nexthop, struct in_addr addr, int neighbor_needed)
{
  struct pim_zlookup_nexthop nexthop_tab[MULTIPATH_NUM];
  struct pim_neighbor *nbr = NULL;
  int num_ifindex;
  struct interface *ifp = NULL;
  ifindex_t first_ifindex = 0;
  int found = 0;
  int i = 0;

  if ((nexthop->last_lookup.s_addr == addr.s_addr) &&
      (nexthop->last_lookup_time > last_route_change_time))
    {
      if (PIM_DEBUG_TRACE)
	{
	  char addr_str[INET_ADDRSTRLEN];
	  pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
          char nexthop_str[PREFIX_STRLEN];
          pim_addr_dump("<nexthop?>", &nexthop->mrib_nexthop_addr,
                            nexthop_str, sizeof(nexthop_str));
          zlog_debug ("%s: Using last lookup for %s at %lld, %lld addr%s",
		      __PRETTY_FUNCTION__,
		      addr_str,
		      nexthop->last_lookup_time,
		      last_route_change_time, nexthop_str);
	}
      nexthop_lookups_avoided++;
      return 0;
    }
  else
    {
      if (PIM_DEBUG_TRACE)
	{
	  char addr_str[INET_ADDRSTRLEN];
	  pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
	  zlog_debug ("%s: Looking up: %s, last lookup time: %lld, %lld",
		      __PRETTY_FUNCTION__,
		      addr_str,
		      nexthop->last_lookup_time,
		      last_route_change_time);
	}
    }

  memset (nexthop_tab, 0, sizeof (struct pim_zlookup_nexthop) * MULTIPATH_NUM);
  num_ifindex = zclient_lookup_nexthop(nexthop_tab,
				       MULTIPATH_NUM,
				       addr, PIM_NEXTHOP_LOOKUP_MAX);
  if (num_ifindex < 1) {
    char addr_str[INET_ADDRSTRLEN];
    pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
    zlog_warn("%s %s: could not find nexthop ifindex for address %s",
	      __FILE__, __PRETTY_FUNCTION__,
	      addr_str);
    return -1;
  }

  while (!found && (i < num_ifindex))
    {
      first_ifindex = nexthop_tab[i].ifindex;

      ifp = if_lookup_by_index(first_ifindex, VRF_DEFAULT);
      if (!ifp)
        {
          if (PIM_DEBUG_ZEBRA)
            {
              char addr_str[INET_ADDRSTRLEN];
              pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
              zlog_debug("%s %s: could not find interface for ifindex %d (address %s)",
                         __FILE__, __PRETTY_FUNCTION__,
                         first_ifindex, addr_str);
            }
	  i++;
	  continue;
        }

      if (!ifp->info)
        {
	  if (PIM_DEBUG_ZEBRA)
	    {
	      char addr_str[INET_ADDRSTRLEN];
	      pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
	      zlog_debug("%s: multicast not enabled on input interface %s (ifindex=%d, RPF for source %s)",
			 __PRETTY_FUNCTION__,
			 ifp->name, first_ifindex, addr_str);
	    }
	  i++;
        }
      else if (neighbor_needed && !pim_if_connected_to_source (ifp, addr))
        {
          nbr = pim_neighbor_find (ifp, nexthop_tab[i].nexthop_addr.u.prefix4);
          if (PIM_DEBUG_PIM_TRACE_DETAIL)
            zlog_debug ("ifp name: %s, pim nbr: %p", ifp->name, nbr);
          if (!nbr && !if_is_loopback (ifp))
            i++;
          else
            found = 1;
        }
      else
        found = 1;
    }

  if (found)
    {
      if (PIM_DEBUG_ZEBRA) {
        char nexthop_str[PREFIX_STRLEN];
        char addr_str[INET_ADDRSTRLEN];
        pim_addr_dump("<nexthop?>", &nexthop_tab[i].nexthop_addr, nexthop_str, sizeof(nexthop_str));
        pim_inet4_dump("<addr?>", addr, addr_str, sizeof(addr_str));
        zlog_debug("%s %s: found nexthop %s for address %s: interface %s ifindex=%d metric=%d pref=%d",
	           __FILE__, __PRETTY_FUNCTION__,
	           nexthop_str, addr_str,
	           ifp->name, first_ifindex,
	           nexthop_tab[i].route_metric,
	           nexthop_tab[i].protocol_distance);
      }
      /* update nextop data */
      nexthop->interface                = ifp;
      nexthop->mrib_nexthop_addr        = nexthop_tab[i].nexthop_addr;
      nexthop->mrib_metric_preference   = nexthop_tab[i].protocol_distance;
      nexthop->mrib_route_metric        = nexthop_tab[i].route_metric;
      nexthop->last_lookup              = addr;
      nexthop->last_lookup_time         = pim_time_monotonic_usec();
      nexthop->nbr                      = nbr;
      return 0;
    }
  else
    return -1;
}

static int nexthop_mismatch(const struct pim_nexthop *nh1,
			    const struct pim_nexthop *nh2)
{
  return (nh1->interface != nh2->interface)                          ||
    (nh1->mrib_nexthop_addr.u.prefix4.s_addr != nh2->mrib_nexthop_addr.u.prefix4.s_addr) ||
    (nh1->mrib_metric_preference != nh2->mrib_metric_preference)     ||
    (nh1->mrib_route_metric != nh2->mrib_route_metric);
}

enum pim_rpf_result pim_rpf_update(struct pim_upstream *up, struct pim_rpf *old, uint8_t is_new)
{
  struct pim_rpf     *rpf = &up->rpf;
  struct pim_rpf     saved;
  struct prefix     nht_p;
  struct pim_nexthop_cache pnc;
  int ret = 0;
  struct prefix src, grp;

  saved.source_nexthop = rpf->source_nexthop;
  saved.rpf_addr = rpf->rpf_addr;

  if (is_new && PIM_DEBUG_ZEBRA)
    {
      char source_str[INET_ADDRSTRLEN];
      pim_inet4_dump ("<source?>", up->upstream_addr, source_str,
                      sizeof (source_str));
      zlog_debug ("%s: NHT Register upstream %s addr %s with Zebra.",
                  __PRETTY_FUNCTION__, up->sg_str, source_str);
    }
  /* Register addr with Zebra NHT */
  nht_p.family = AF_INET;
  nht_p.prefixlen = IPV4_MAX_BITLEN;
  nht_p.u.prefix4.s_addr = up->upstream_addr.s_addr;

  src.family = AF_INET;
  src.prefixlen = IPV4_MAX_BITLEN;
  src.u.prefix4 = up->upstream_addr;    //RP or Src address
  grp.family = AF_INET;
  grp.prefixlen = IPV4_MAX_BITLEN;
  grp.u.prefix4 = up->sg.grp;
  memset (&pnc, 0, sizeof (struct pim_nexthop_cache));
  if ((ret = pim_find_or_track_nexthop (&nht_p, up, NULL, &pnc)) == 1)
    {
      if (pnc.nexthop_num)
        {
          //Compute PIM RPF using Cached nexthop
          pim_ecmp_nexthop_search (&pnc, &up->rpf.source_nexthop,
                                   &src, &grp,
                                   !PIM_UPSTREAM_FLAG_TEST_FHR (up->flags) &&
                                   !PIM_UPSTREAM_FLAG_TEST_SRC_IGMP (up->
                                                                     flags));
        }
    }
  else
    {
      if (pim_ecmp_nexthop_lookup (&rpf->source_nexthop,
                                   up->upstream_addr, &src, &grp,
                                   !PIM_UPSTREAM_FLAG_TEST_FHR (up->flags) &&
                                   !PIM_UPSTREAM_FLAG_TEST_SRC_IGMP (up->
                                                                     flags)))
        {
          return PIM_RPF_FAILURE;
        }
   }

  rpf->rpf_addr.family = AF_INET;
  rpf->rpf_addr.u.prefix4 = pim_rpf_find_rpf_addr(up);
  if (pim_rpf_addr_is_inaddr_any(rpf) && PIM_DEBUG_ZEBRA) {
    /* RPF'(S,G) not found */
    zlog_debug("%s %s: RPF'%s not found: won't send join upstream",
	       __FILE__, __PRETTY_FUNCTION__,
	       up->sg_str);
    /* warning only */
  }

  /* detect change in pim_nexthop */
  if (nexthop_mismatch(&rpf->source_nexthop, &saved.source_nexthop)) {

    if (PIM_DEBUG_ZEBRA) {
      char nhaddr_str[PREFIX_STRLEN];
      pim_addr_dump("<addr?>", &rpf->source_nexthop.mrib_nexthop_addr, nhaddr_str, sizeof(nhaddr_str));
      zlog_debug("%s %s: (S,G)=%s source nexthop now is: interface=%s address=%s pref=%d metric=%d",
		 __FILE__, __PRETTY_FUNCTION__,
		 up->sg_str,
		 rpf->source_nexthop.interface ? rpf->source_nexthop.interface->name : "<ifname?>",
		 nhaddr_str,
		 rpf->source_nexthop.mrib_metric_preference,
		 rpf->source_nexthop.mrib_route_metric);
    }

    pim_upstream_update_join_desired(up);
    pim_upstream_update_could_assert(up);
    pim_upstream_update_my_assert_metric(up);
  }

  /* detect change in RPF_interface(S) */
  if (saved.source_nexthop.interface != rpf->source_nexthop.interface) {

    if (PIM_DEBUG_ZEBRA) {
      zlog_debug("%s %s: (S,G)=%s RPF_interface(S) changed from %s to %s",
		 __FILE__, __PRETTY_FUNCTION__,
		 up->sg_str,
		 saved.source_nexthop.interface ? saved.source_nexthop.interface->name : "<oldif?>",
		 rpf->source_nexthop.interface ? rpf->source_nexthop.interface->name : "<newif?>");
      /* warning only */
    }

    pim_upstream_rpf_interface_changed(up, saved.source_nexthop.interface);
  }

  /* detect change in RPF'(S,G) */
  if (saved.rpf_addr.u.prefix4.s_addr != rpf->rpf_addr.u.prefix4.s_addr ||
      saved.source_nexthop.interface != rpf->source_nexthop.interface)
    {

    /* return old rpf to caller ? */
    if (old)
      {
        old->source_nexthop = saved.source_nexthop;
        old->rpf_addr = saved.rpf_addr;
      }
    return PIM_RPF_CHANGED;
  }

  return PIM_RPF_OK;
}

/*
  RFC 4601: 4.1.6.  State Summarization Macros

     neighbor RPF'(S,G) {
         if ( I_Am_Assert_Loser(S, G, RPF_interface(S) )) {
              return AssertWinner(S, G, RPF_interface(S) )
         } else {
              return NBR( RPF_interface(S), MRIB.next_hop( S ) )
         }
     }

  RPF'(*,G) and RPF'(S,G) indicate the neighbor from which data
  packets should be coming and to which joins should be sent on the RP
  tree and SPT, respectively.
*/
static struct in_addr pim_rpf_find_rpf_addr(struct pim_upstream *up)
{
  struct pim_ifchannel *rpf_ch;
  struct pim_neighbor *neigh;
  struct in_addr rpf_addr;

  if (!up->rpf.source_nexthop.interface) {
    zlog_warn("%s: missing RPF interface for upstream (S,G)=%s",
	      __PRETTY_FUNCTION__,
	      up->sg_str);

    rpf_addr.s_addr = PIM_NET_INADDR_ANY;
    return rpf_addr;
  }

  rpf_ch = pim_ifchannel_find(up->rpf.source_nexthop.interface,
			      &up->sg);
  if (rpf_ch) {
    if (rpf_ch->ifassert_state == PIM_IFASSERT_I_AM_LOSER) {
      return rpf_ch->ifassert_winner;
    }
  }

  /* return NBR( RPF_interface(S), MRIB.next_hop( S ) ) */

  neigh = pim_if_find_neighbor(up->rpf.source_nexthop.interface,
			       up->rpf.source_nexthop.mrib_nexthop_addr.u.prefix4);
  if (neigh)
    rpf_addr = neigh->source_addr;
  else
    rpf_addr.s_addr = PIM_NET_INADDR_ANY;

  return rpf_addr;
}

int
pim_rpf_addr_is_inaddr_none (struct pim_rpf *rpf)
{
  switch (rpf->rpf_addr.family)
    {
    case AF_INET:
      return rpf->rpf_addr.u.prefix4.s_addr == INADDR_NONE;
      break;
    case AF_INET6:
      zlog_warn ("%s: v6 Unimplmeneted", __PRETTY_FUNCTION__);
      return 1;
      break;
    default:
      return 0;
      break;
    }

  return 0;
}

int
pim_rpf_addr_is_inaddr_any (struct pim_rpf *rpf)
{
  switch (rpf->rpf_addr.family)
    {
    case AF_INET:
      return rpf->rpf_addr.u.prefix4.s_addr == INADDR_ANY;
      break;
    case AF_INET6:
      zlog_warn ("%s: v6 Unimplmented", __PRETTY_FUNCTION__);
      return 1;
      break;
    default:
      return 0;
      break;
    }

  return 0;
}

int
pim_rpf_is_same (struct pim_rpf *rpf1, struct pim_rpf *rpf2)
{
  if (rpf1->source_nexthop.interface == rpf2->source_nexthop.interface)
    return 1;

  return 0;
}