path: root/pimd/pim_join.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 "log.h"
#include "prefix.h"
#include "if.h"
#include "vty.h"
#include "plist.h"

#include "pimd.h"
#include "pim_str.h"
#include "pim_tlv.h"
#include "pim_msg.h"
#include "pim_pim.h"
#include "pim_join.h"
#include "pim_oil.h"
#include "pim_iface.h"
#include "pim_hello.h"
#include "pim_ifchannel.h"
#include "pim_rpf.h"
#include "pim_rp.h"
#include "pim_jp_agg.h"

static void
on_trace (const char *label,
	  struct interface *ifp, struct in_addr src)
{
  if (PIM_DEBUG_PIM_TRACE) {
    char src_str[INET_ADDRSTRLEN];
    pim_inet4_dump("<src?>", src, src_str, sizeof(src_str));
    zlog_debug("%s: from %s on %s",
	       label, src_str, ifp->name);
  }
}

static void recv_join(struct interface *ifp,
		      struct pim_neighbor *neigh,
		      uint16_t holdtime,
		      struct in_addr upstream,
		      struct prefix_sg *sg,
		      uint8_t source_flags)
{
  if (PIM_DEBUG_PIM_TRACE) {
    char up_str[INET_ADDRSTRLEN];
    char neigh_str[INET_ADDRSTRLEN];
    pim_inet4_dump("<upstream?>", upstream, up_str, sizeof(up_str));
    pim_inet4_dump("<neigh?>", neigh->source_addr, neigh_str, sizeof(neigh_str));
    zlog_warn("%s: join (S,G)=%s rpt=%d wc=%d upstream=%s holdtime=%d from %s on %s",
	      __PRETTY_FUNCTION__,
	      pim_str_sg_dump (sg),
	      source_flags & PIM_RPT_BIT_MASK,
	      source_flags & PIM_WILDCARD_BIT_MASK,
	      up_str, holdtime, neigh_str, ifp->name);
  }

  /*
   * If the RPT and WC are set it's a (*,G)
   * and the source is the RP
   */
  if ((source_flags & PIM_RPT_BIT_MASK) &&
      (source_flags & PIM_WILDCARD_BIT_MASK))
    {
      struct pim_rpf *rp = RP (sg->grp);

      /*
       * If the RP sent in the message is not
       * our RP for the group, drop the message
       */
      if (sg->src.s_addr != rp->rpf_addr.u.prefix4.s_addr)
	return;

      sg->src.s_addr = INADDR_ANY;
    }

  /* Restart join expiry timer */
  pim_ifchannel_join_add(ifp, neigh->source_addr, upstream,
			 sg, source_flags, holdtime);

}

static void recv_prune(struct interface *ifp,
		       struct pim_neighbor *neigh,
		       uint16_t holdtime,
		       struct in_addr upstream,
		       struct prefix_sg *sg,
		       uint8_t source_flags)
{
  if (PIM_DEBUG_PIM_TRACE) {
    char up_str[INET_ADDRSTRLEN];
    char neigh_str[INET_ADDRSTRLEN];
    pim_inet4_dump("<upstream?>", upstream, up_str, sizeof(up_str));
    pim_inet4_dump("<neigh?>", neigh->source_addr, neigh_str, sizeof(neigh_str));
    zlog_warn("%s: prune (S,G)=%s rpt=%d wc=%d upstream=%s holdtime=%d from %s on %s",
	      __PRETTY_FUNCTION__,
	      pim_str_sg_dump (sg),
	      source_flags & PIM_RPT_BIT_MASK,
	      source_flags & PIM_WILDCARD_BIT_MASK,
	      up_str, holdtime, neigh_str, ifp->name);
  }

  if ((source_flags & PIM_RPT_BIT_MASK) &&
      (source_flags & PIM_WILDCARD_BIT_MASK))
    {
      struct pim_rpf *rp = RP (sg->grp);

      // Ignoring Prune *,G's at the moment.
      if (sg->src.s_addr != rp->rpf_addr.u.prefix4.s_addr)
	return;

      sg->src.s_addr = INADDR_ANY;
    }

  pim_ifchannel_prune(ifp, upstream, sg, source_flags, holdtime);

}

int pim_joinprune_recv(struct interface *ifp,
		       struct pim_neighbor *neigh,
		       struct in_addr src_addr,
		       uint8_t *tlv_buf, int tlv_buf_size)
{
  struct prefix   msg_upstream_addr;
  uint8_t         msg_num_groups;
  uint16_t        msg_holdtime;
  int             addr_offset;
  uint8_t        *buf;
  uint8_t        *pastend;
  int             remain;
  int             group;

  buf     = tlv_buf;
  pastend = tlv_buf + tlv_buf_size;

  /*
    Parse ucast addr
  */
  addr_offset = pim_parse_addr_ucast (&msg_upstream_addr,
				      buf, pastend - buf);
  if (addr_offset < 1) {
    char src_str[INET_ADDRSTRLEN];
    pim_inet4_dump("<src?>", src_addr, src_str, sizeof(src_str));
    zlog_warn("%s: pim_parse_addr_ucast() failure: from %s on %s",
	      __PRETTY_FUNCTION__,
	      src_str, ifp->name);
    return -1;
  }
  buf += addr_offset;

  /*
    Check upstream address family
   */
  if (msg_upstream_addr.family != AF_INET) {
    if (PIM_DEBUG_PIM_J_P) {
      char src_str[INET_ADDRSTRLEN];
      pim_inet4_dump("<src?>", src_addr, src_str, sizeof(src_str));
      zlog_warn("%s: ignoring join/prune directed to unexpected addr family=%d from %s on %s",
		__PRETTY_FUNCTION__,
		msg_upstream_addr.family, src_str, ifp->name);
    }
    return -2;
  }

  remain = pastend - buf;
  if (remain < 4) {
    char src_str[INET_ADDRSTRLEN];
    pim_inet4_dump("<src?>", src_addr, src_str, sizeof(src_str));
    zlog_warn("%s: short join/prune message buffer for group list: size=%d minimum=%d from %s on %s",
	      __PRETTY_FUNCTION__,
	      remain, 4, src_str, ifp->name);
    return -4;
  }

  ++buf; /* skip reserved byte */
  msg_num_groups = *(const uint8_t *) buf;
  ++buf;
  msg_holdtime = ntohs(*(const uint16_t *) buf);
  ++buf;
  ++buf;

  if (PIM_DEBUG_PIM_J_P) {
    char src_str[INET_ADDRSTRLEN];
    char upstream_str[INET_ADDRSTRLEN];
    pim_inet4_dump("<src?>", src_addr, src_str, sizeof(src_str));
    pim_inet4_dump("<addr?>", msg_upstream_addr.u.prefix4,
		   upstream_str, sizeof(upstream_str));
    zlog_debug ("%s: join/prune upstream=%s groups=%d holdtime=%d from %s on %s",
		__PRETTY_FUNCTION__,
		upstream_str, msg_num_groups, msg_holdtime,
		src_str, ifp->name);
  }

  /* Scan groups */
  for (group = 0; group < msg_num_groups; ++group) {
    struct prefix_sg sg;
    uint8_t       msg_source_flags;
    uint16_t      msg_num_joined_sources;
    uint16_t      msg_num_pruned_sources;
    int           source;
    struct        pim_ifchannel *ch = NULL;

    memset (&sg, 0, sizeof (struct prefix_sg));
    addr_offset = pim_parse_addr_group (&sg,
					buf, pastend - buf);
    if (addr_offset < 1) {
      return -5;
    }
    buf += addr_offset;

    remain = pastend - buf;
    if (remain < 4) {
      char src_str[INET_ADDRSTRLEN];
      pim_inet4_dump("<src?>", src_addr, src_str, sizeof(src_str));
      zlog_warn("%s: short join/prune buffer for source list: size=%d minimum=%d from %s on %s",
		__PRETTY_FUNCTION__,
		remain, 4, src_str, ifp->name);
      return -6;
    }

    msg_num_joined_sources = ntohs(*(const uint16_t *) buf);
    buf += 2;
    msg_num_pruned_sources = ntohs(*(const uint16_t *) buf);
    buf += 2;

    if (PIM_DEBUG_PIM_J_P) {
      char src_str[INET_ADDRSTRLEN];
      char upstream_str[INET_ADDRSTRLEN];
      char group_str[INET_ADDRSTRLEN];
      pim_inet4_dump("<src?>", src_addr, src_str, sizeof(src_str));
      pim_inet4_dump("<addr?>", msg_upstream_addr.u.prefix4,
		     upstream_str, sizeof(upstream_str));
      pim_inet4_dump("<grp?>", sg.grp,
		     group_str, sizeof(group_str));
      zlog_warn("%s: join/prune upstream=%s group=%s/32 join_src=%d prune_src=%d from %s on %s",
		__PRETTY_FUNCTION__,
		upstream_str, group_str,
		msg_num_joined_sources, msg_num_pruned_sources,
		src_str, ifp->name);
    }

    /* Scan joined sources */
    for (source = 0; source < msg_num_joined_sources; ++source) {
      addr_offset = pim_parse_addr_source (&sg,
					   &msg_source_flags,
					   buf, pastend - buf);
      if (addr_offset < 1) {
	return -7;
      }

      buf += addr_offset;

      recv_join(ifp, neigh, msg_holdtime,
		msg_upstream_addr.u.prefix4,
		&sg,
		msg_source_flags);

      if (sg.src.s_addr == INADDR_ANY)
        {
          ch = pim_ifchannel_find (ifp, &sg);
	  if (ch)
	    pim_ifchannel_set_star_g_join_state (ch, 0);
        }
    }

    /* Scan pruned sources */
    for (source = 0; source < msg_num_pruned_sources; ++source) {
      addr_offset = pim_parse_addr_source (&sg,
					   &msg_source_flags,
					   buf, pastend - buf);
      if (addr_offset < 1) {
	return -8;
      }

      buf += addr_offset;

      recv_prune(ifp, neigh, msg_holdtime,
		 msg_upstream_addr.u.prefix4,
		 &sg,
		 msg_source_flags);
    }
    if (ch)
      pim_ifchannel_set_star_g_join_state (ch, 1);
    ch = NULL;
  } /* scan groups */

  return 0;
}

/*
 * J/P Message Format
 *
 * While the RFC clearly states that this is 32 bits wide, it
 * is cheating.  These fields:
 * Encoded-Unicast format   (6 bytes MIN)
 * Encoded-Group format     (8 bytes MIN)
 * Encoded-Source format    (8 bytes MIN)
 * are *not* 32 bits wide.
 *
 * Nor does the RFC explicitly call out the size for:
 * Reserved                 (1 byte)
 * Num Groups               (1 byte)
 * Holdtime                 (2 bytes)
 * Number of Joined Sources (2 bytes)
 * Number of Pruned Sources (2 bytes)
 *
 * This leads to a missleading representation from casual
 * reading and making assumptions.  Be careful!
 *
 *   0                   1                   2                   3
 *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |PIM Ver| Type  |   Reserved    |           Checksum            |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |        Upstream Neighbor Address (Encoded-Unicast format)     |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |  Reserved     | Num groups    |          Holdtime             |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |         Multicast Group Address 1 (Encoded-Group format)      |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |   Number of Joined Sources    |   Number of Pruned Sources    |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |        Joined Source Address 1 (Encoded-Source format)        |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |                             .                                 |
 *  |                             .                                 |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |        Joined Source Address n (Encoded-Source format)        |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |        Pruned Source Address 1 (Encoded-Source format)        |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |                             .                                 |
 *  |                             .                                 |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |        Pruned Source Address n (Encoded-Source format)        |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |         Multicast Group Address m (Encoded-Group format)      |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |   Number of Joined Sources    |   Number of Pruned Sources    |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |        Joined Source Address 1 (Encoded-Source format)        |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |                             .                                 |
 *  |                             .                                 |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |        Joined Source Address n (Encoded-Source format)        |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |        Pruned Source Address 1 (Encoded-Source format)        |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |                             .                                 |
 *  |                             .                                 |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *  |        Pruned Source Address n (Encoded-Source format)        |
 *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 */
int pim_joinprune_send(struct pim_rpf *rpf,
                       struct list *groups)
{
  struct pim_jp_agg_group *group;
  struct pim_interface *pim_ifp;
  struct pim_jp_groups *grp = NULL;
  struct pim_jp *msg;
  struct listnode *node, *nnode;
  uint8_t pim_msg[10000];
  uint8_t *curr_ptr = pim_msg;
  bool new_packet = true;
  size_t packet_left = 0;
  size_t packet_size = 0;
  size_t group_size = 0;

  on_trace (__PRETTY_FUNCTION__, rpf->source_nexthop.interface, rpf->rpf_addr.u.prefix4);

  pim_ifp = rpf->source_nexthop.interface->info;

  if (!pim_ifp) {
    zlog_warn("%s: multicast not enabled on interface %s",
              __PRETTY_FUNCTION__,
              rpf->source_nexthop.interface->name);
    return -1;
  }

  if (PIM_INADDR_IS_ANY(rpf->rpf_addr.u.prefix4))
    {
      if (PIM_DEBUG_PIM_J_P) {
        char dst_str[INET_ADDRSTRLEN];
        pim_inet4_dump("<dst?>", rpf->rpf_addr.u.prefix4, dst_str, sizeof(dst_str));
        zlog_debug("%s: upstream=%s is myself on interface %s",
                   __PRETTY_FUNCTION__,
                   dst_str, rpf->source_nexthop.interface->name);
      }
      return 0;
    }

  /*
    RFC 4601: 4.3.1.  Sending Hello Messages

    Thus, if a router needs to send a Join/Prune or Assert message on
    an interface on which it has not yet sent a Hello message with the
    currently configured IP address, then it MUST immediately send the
    relevant Hello message without waiting for the Hello Timer to
    expire, followed by the Join/Prune or Assert message.
  */
  pim_hello_require(rpf->source_nexthop.interface);

  for (ALL_LIST_ELEMENTS(groups, node, nnode, group))
    {
      if (new_packet)
        {
          msg = (struct pim_jp *)pim_msg;

          memset(msg, 0, sizeof (*msg));

          pim_msg_addr_encode_ipv4_ucast ((uint8_t *)&msg->addr, rpf->rpf_addr.u.prefix4);
          msg->reserved   = 0;
          msg->holdtime   = htons(PIM_JP_HOLDTIME);

          new_packet = false;

          grp = &msg->groups[0];
          curr_ptr = (uint8_t *)grp;
          packet_size  = sizeof (struct pim_msg_header);
          packet_size += sizeof (struct pim_encoded_ipv4_unicast);
          packet_size += 4;  // reserved (1) + groups (1) + holdtime (2)

          packet_left = rpf->source_nexthop.interface->mtu - 24;
          packet_left -= packet_size;
        }
      if (PIM_DEBUG_PIM_J_P) {
        char dst_str[INET_ADDRSTRLEN];
        char grp_str[INET_ADDRSTRLEN];
        pim_inet4_dump("<dst?>", rpf->rpf_addr.u.prefix4, dst_str, sizeof(dst_str));
        pim_inet4_dump("<grp?>", group->group, grp_str, sizeof(grp_str));
        zlog_debug("%s: sending (G)=%s to upstream=%s on interface %s",
                   __PRETTY_FUNCTION__,
                   grp_str, dst_str, rpf->source_nexthop.interface->name);
      }

      group_size = pim_msg_get_jp_group_size (group->sources);
      if (group_size > packet_left)
        {
          pim_msg_build_header (pim_msg, packet_size, PIM_MSG_TYPE_JOIN_PRUNE);
          if (pim_msg_send(pim_ifp->pim_sock_fd,
                           pim_ifp->primary_address,
                           qpim_all_pim_routers_addr,
                           pim_msg,
                           packet_size,
                           rpf->source_nexthop.interface->name)) {
            zlog_warn("%s: could not send PIM message on interface %s",
                      __PRETTY_FUNCTION__, rpf->source_nexthop.interface->name);
          }

          msg = (struct pim_jp *)pim_msg;
          memset(msg, 0, sizeof (*msg));

          pim_msg_addr_encode_ipv4_ucast ((uint8_t *)&msg->addr, rpf->rpf_addr.u.prefix4);
          msg->reserved   = 0;
          msg->holdtime   = htons(PIM_JP_HOLDTIME);

          new_packet = false;

          grp = &msg->groups[0];
          curr_ptr = (uint8_t *)grp;
          packet_size  = sizeof (struct pim_msg_header);
          packet_size += sizeof (struct pim_encoded_ipv4_unicast);
          packet_size += 4;  // reserved (1) + groups (1) + holdtime (2)

          packet_left = rpf->source_nexthop.interface->mtu - 24;
          packet_left -= packet_size;
        }

      msg->num_groups++;
      /*
        Build PIM message
      */

      curr_ptr += group_size;
      packet_left -= group_size;
      packet_size += group_size;
      pim_msg_build_jp_groups (grp, group);

      grp = (struct pim_jp_groups *)curr_ptr;
      if (packet_left < sizeof (struct pim_jp_groups) || msg->num_groups == 255)
        {
          pim_msg_build_header (pim_msg, packet_size, PIM_MSG_TYPE_JOIN_PRUNE);
          if (pim_msg_send(pim_ifp->pim_sock_fd,
                           pim_ifp->primary_address,
                           qpim_all_pim_routers_addr,
                           pim_msg,
                           packet_size,
                           rpf->source_nexthop.interface->name)) {
            zlog_warn("%s: could not send PIM message on interface %s",
                      __PRETTY_FUNCTION__, rpf->source_nexthop.interface->name);
          }

          new_packet = true;
        }
    }


  if (!new_packet)
    {
      //msg->num_groups = htons (msg->num_groups);
      pim_msg_build_header (pim_msg, packet_size, PIM_MSG_TYPE_JOIN_PRUNE);
      if (pim_msg_send(pim_ifp->pim_sock_fd,
                       pim_ifp->primary_address,
                       qpim_all_pim_routers_addr,
                       pim_msg,
                       packet_size,
                       rpf->source_nexthop.interface->name)) {
        zlog_warn("%s: could not send PIM message on interface %s",
                  __PRETTY_FUNCTION__, rpf->source_nexthop.interface->name);
      }
    }
  return 0;
}