mirror_frr/pimd/pim_igmpv2.c

/*
 * PIM for Quagga
 * Copyright (C) 2016 Cumulus Networks, Inc.
 * Daniel Walton
 *
 * 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 "pimd.h"
#include "pim_igmp.h"
#include "pim_igmpv2.h"
#include "pim_igmpv3.h"
#include "pim_str.h"
#include "pim_time.h"
#include "pim_util.h"


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

void
igmp_v2_send_query (struct igmp_group *group,
                    int fd,
                    const char *ifname,
                    char *query_buf,
                    struct in_addr dst_addr,
                    struct in_addr group_addr,
                    int query_max_response_time_dsec)
{
  ssize_t             msg_size = 8;
  uint8_t             max_resp_code;
  ssize_t             sent;
  struct sockaddr_in  to;
  socklen_t           tolen;
  uint16_t            checksum;

  /* max_resp_code must be non-zero else this will look like an IGMP v1 query */
  max_resp_code = igmp_msg_encode16to8(query_max_response_time_dsec);
  zassert(max_resp_code > 0);

  query_buf[0] = PIM_IGMP_MEMBERSHIP_QUERY;
  query_buf[1] = max_resp_code;
  *(uint16_t *)(query_buf + IGMP_CHECKSUM_OFFSET)   = 0; /* for computing checksum */
  memcpy(query_buf+4, &group_addr, sizeof(struct in_addr));

  checksum = in_cksum(query_buf, msg_size);
  *(uint16_t *)(query_buf + IGMP_CHECKSUM_OFFSET) = checksum;

  if (PIM_DEBUG_IGMP_PACKETS) {
    char dst_str[INET_ADDRSTRLEN];
    char group_str[INET_ADDRSTRLEN];
    pim_inet4_dump("<dst?>", dst_addr, dst_str, sizeof(dst_str));
    pim_inet4_dump("<group?>", group_addr, group_str, sizeof(group_str));
    zlog_debug("Send IGMPv2 QUERY to %s on %s for group %s",
	       dst_str, ifname, group_str);
  }

  memset(&to, 0, sizeof(to));
  to.sin_family = AF_INET;
  to.sin_addr = dst_addr;
  tolen = sizeof(to);

  sent = sendto(fd, query_buf, msg_size, MSG_DONTWAIT,
                (struct sockaddr *)&to, tolen);
  if (sent != (ssize_t) msg_size) {
    char dst_str[INET_ADDRSTRLEN];
    char group_str[INET_ADDRSTRLEN];
    pim_inet4_dump("<dst?>", dst_addr, dst_str, sizeof(dst_str));
    pim_inet4_dump("<group?>", group_addr, group_str, sizeof(group_str));
    if (sent < 0) {
      zlog_warn("Send IGMPv2 QUERY failed due to %s on %s: group=%s msg_size=%zd: errno=%d: %s",
		dst_str, ifname, group_str, msg_size, errno, safe_strerror(errno));
    }
    else {
      zlog_warn("Send IGMPv2 QUERY failed due to %s on %s: group=%s msg_size=%zd: sent=%zd",
		dst_str, ifname, group_str, msg_size, sent);
    }
    return;
  }
}

int
igmp_v2_recv_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 in_addr group_addr;
  char group_str[INET_ADDRSTRLEN];

  on_trace(__PRETTY_FUNCTION__, igmp->interface, from);

  if (igmp_msg_len != IGMP_V12_MSG_SIZE) {
    zlog_warn("Recv IGMPv2 REPORT from %s on %s: size=%d other than correct=%d",
              from_str, ifp->name, igmp_msg_len, IGMP_V12_MSG_SIZE);
    return -1;
  }

  memcpy(&group_addr, igmp_msg + 4, sizeof(struct in_addr));

  if (PIM_DEBUG_IGMP_PACKETS) {
    pim_inet4_dump("<dst?>", group_addr, group_str, sizeof(group_str));
    zlog_debug("Recv IGMPv2 REPORT from %s on %s for %s",
               from_str, ifp->name, group_str);
  }

  /*
   * RFC 3376
   * 7.3.2. In the Presence of Older Version Group Members
   *
   * When Group Compatibility Mode is IGMPv2, a router internally
   * translates the following IGMPv2 messages for that group to their
   * IGMPv3 equivalents:
   *
   * IGMPv2 Message                IGMPv3 Equivalent
   * --------------                -----------------
   * Report                        IS_EX( {} )
   * Leave                         TO_IN( {} )
   */
  igmpv3_report_isex (igmp, from, group_addr, 0, NULL, 1);

  return 0;
}

int
igmp_v2_recv_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;
  struct in_addr group_addr;
  char group_str[INET_ADDRSTRLEN];

  on_trace(__PRETTY_FUNCTION__, igmp->interface, from);

  if (igmp_msg_len != IGMP_V12_MSG_SIZE) {
    zlog_warn("Recv IGMPv2 LEAVE from %s on %s: size=%d other than correct=%d",
              from_str, ifp->name, igmp_msg_len, IGMP_V12_MSG_SIZE);
    return -1;
  }

  memcpy(&group_addr, igmp_msg + 4, sizeof(struct in_addr));

  if (PIM_DEBUG_IGMP_PACKETS) {
    pim_inet4_dump("<dst?>", group_addr, group_str, sizeof(group_str));
    zlog_debug("Recv IGMPv2 LEAVE from %s on %s for %s",
               from_str, ifp->name, group_str);
  }

  /*
   * RFC 3376
   * 7.3.2. In the Presence of Older Version Group Members
   *
   * When Group Compatibility Mode is IGMPv2, a router internally
   * translates the following IGMPv2 messages for that group to their
   * IGMPv3 equivalents:
   *
   * IGMPv2 Message                IGMPv3 Equivalent
   * --------------                -----------------
   * Report                        IS_EX( {} )
   * Leave                         TO_IN( {} )
   */
  igmpv3_report_toin (igmp, from, group_addr, 0, NULL);

  return 0;
}