SOCK_Dgram_Mcast.cpp

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// $Id: SOCK_Dgram_Mcast.cpp 81517 2008-04-29 07:23:47Z johnnyw $

#include "ace/SOCK_Dgram_Mcast.h"

#include "ace/OS_Memory.h"
#include "ace/OS_NS_string.h"
#include "ace/OS_NS_errno.h"
#include "ace/os_include/net/os_if.h"
#include "ace/os_include/arpa/os_inet.h"

#if defined (__linux__) && defined (ACE_HAS_IPV6)
#include "ace/OS_NS_sys_socket.h"
#endif

#if defined (ACE_HAS_IPV6) && defined (ACE_WIN32)
#include /**/ <Iphlpapi.h>
#endif

#if !defined (__ACE_INLINE__)
#include "ace/SOCK_Dgram_Mcast.inl"
#endif /* __ACE_INLINE__ */

ACE_RCSID (ace,
           SOCK_Dgram_Mcast,
           "$Id: SOCK_Dgram_Mcast.cpp 81517 2008-04-29 07:23:47Z johnnyw $")

#include "ace/Log_Msg.h"

// This is a workaround for platforms with non-standard
// definitions of the ip_mreq structure
#if ! defined (IMR_MULTIADDR)
#define IMR_MULTIADDR imr_multiaddr
#endif /* ! defined (IMR_MULTIADDR) */

ACE_BEGIN_VERSIONED_NAMESPACE_DECL

// Helper (inline) functions.
class ACE_SDM_helpers
{
public:
  // Convert ACE_INET_Addr to string, using local formatting rules.

  static void addr_to_string (const ACE_INET_Addr &ip_addr,
                              ACE_TCHAR *ret_string,  // results here.
                              size_t len,
                              int clip_portnum)       // clip port# info?
    {
      if (ip_addr.addr_to_string (ret_string, len, 1) == -1)
        ACE_OS::strcpy (ret_string, ACE_TEXT ("<?>"));
      else
        {
          ACE_TCHAR *pc = ACE_OS::strrchr (ret_string, ACE_TEXT (':'));
          if (clip_portnum && pc)
            *pc = ACE_TEXT ('\0'); // clip port# info.
        }
    }
    // op== for ip_mreq structs.
    static int is_equal (const ip_mreq &m1, const ip_mreq &m2)
      {
        return m1.IMR_MULTIADDR.s_addr == m2.IMR_MULTIADDR.s_addr
          && m1.imr_interface.s_addr == m2.imr_interface.s_addr;
      }
};

ACE_ALLOC_HOOK_DEFINE (ACE_SOCK_Dgram_Mcast)

void
ACE_SOCK_Dgram_Mcast::dump (void) const
{
#if defined (ACE_HAS_DUMP)
  ACE_TRACE ("ACE_SOCK_Dgram_Mcast::dump");

  ACE_DEBUG ((LM_DEBUG, ACE_BEGIN_DUMP, this));

# if defined (ACE_SOCK_DGRAM_MCAST_DUMPABLE)
  ACE_TCHAR addr_string[MAXNAMELEN + 1];

  ACE_DEBUG ((LM_DEBUG,
              ACE_TEXT ("\nOptions: bindaddr=%s, nulliface=%s\n"),
              ACE_BIT_ENABLED (this->opts_, OPT_BINDADDR_YES) ?
                ACE_TEXT ("<Bound>") : ACE_TEXT ("<Not Bound>"),
              ACE_BIT_ENABLED (this->opts_, OPT_NULLIFACE_ALL) ?
                ACE_TEXT ("<All Ifaces>") : ACE_TEXT ("<Default Iface>")));

  // Show default send addr, port#, and interface.
  ACE_SDM_helpers::addr_to_string (this->send_addr_, addr_string,
                                   sizeof addr_string, 0);
  ACE_DEBUG ((LM_DEBUG,
              ACE_TEXT ("Send addr=%s iface=%s\n"),
              addr_string,
              this->send_net_if_ ? this->send_net_if_
                                 : ACE_TEXT ("<default>")));

  // Show list of subscribed addresses.
  ACE_DEBUG ((LM_DEBUG, ACE_TEXT ("Subscription list:\n")));

  ACE_MT (ACE_GUARD (ACE_SDM_LOCK, guard, this->subscription_list_lock_));
  subscription_list_iter_t  iter (this->subscription_list_);
  for ( ; !iter.done (); iter.advance ())
    {
      ACE_TCHAR iface_string[MAXNAMELEN + 1];
      ip_mreq *pm = iter.next ();

      // Get subscribed address (w/out port# info - not relevant).
      ACE_INET_Addr ip_addr (static_cast<u_short> (0),
                             ACE_NTOHL (pm->IMR_MULTIADDR.s_addr));
      ACE_SDM_helpers::addr_to_string (ip_addr, addr_string,
                                       sizeof addr_string, 1);

      // Get interface address/specification.
      ACE_INET_Addr if_addr (static_cast<u_short> (0),
                             ACE_NTOHL (pm->imr_interface.s_addr));
      ACE_SDM_helpers::addr_to_string (if_addr, iface_string,
                                       sizeof iface_string, 1);
      if (ACE_OS::strcmp (iface_string, ACE_TEXT ("0.0.0.0")) == 0)
        // Receives on system default iface. (Note that null_iface_opt_
        // option processing has already occurred.)
        ACE_OS::strcpy (iface_string, ACE_TEXT ("<default>"));

      // Dump info.
      ACE_DEBUG ((LM_DEBUG,
                  ACE_TEXT ("\taddr=%s iface=%s\n"),
                  addr_string,
                  iface_string));
    }
# endif /* ACE_SOCK_DGRAM_MCAST_DUMPABLE */
  ACE_DEBUG ((LM_DEBUG, ACE_END_DUMP));
#endif /* ACE_HAS_DUMP */
}

// Constructor.
ACE_SOCK_Dgram_Mcast::ACE_SOCK_Dgram_Mcast
  (ACE_SOCK_Dgram_Mcast::options opts)
  :  opts_ (opts),
     send_net_if_ (0)
{
  ACE_TRACE ("ACE_SOCK_Dgram_Mcast::ACE_SOCK_Dgram_Mcast");
}

// Destructor.
ACE_SOCK_Dgram_Mcast::~ACE_SOCK_Dgram_Mcast (void)
{
  ACE_TRACE ("ACE_SOCK_Dgram_Mcast::~ACE_SOCK_Dgram_Mcast");

  // Free memory and optionally unsubscribe from currently subscribed group(s).
  delete [] this->send_net_if_;
  this->clear_subs_list ();
}

int
ACE_SOCK_Dgram_Mcast::open (const ACE_INET_Addr &mcast_addr,
                            const ACE_TCHAR *net_if,
                            int reuse_addr)
{
  ACE_TRACE ("ACE_SOCK_Dgram_Mcast::open");

  // Only perform the <open> initialization if we haven't been opened
  // earlier.
  // No sanity check?  We should probably flag an error if the user
  // makes multiple calls to open().
  if (this->get_handle () != ACE_INVALID_HANDLE)
    return 0;

  // Invoke lower-layer ::open.
  if (ACE_SOCK::open (SOCK_DGRAM,
                      mcast_addr.get_type (),
                      0, // always use 0
                      reuse_addr) == -1)
    return -1;

  return this->open_i (mcast_addr, net_if, reuse_addr);
}

int
ACE_SOCK_Dgram_Mcast::open_i (const ACE_INET_Addr &mcast_addr,
                              const ACE_TCHAR *net_if,
                              int reuse_addr)
{
  ACE_TRACE ("ACE_SOCK_Dgram_Mcast::open_i");
  // ACE_SOCK::open calls this if reuse_addr is set, so we only need to
  // process port reuse option.
  if (reuse_addr)
    {
#if defined (SO_REUSEPORT)
      int one = 1;
      if (this->ACE_SOCK::set_option (SOL_SOCKET,
                                      SO_REUSEPORT,
                                      &one,
                                      sizeof one) == -1)
        return -1;
#endif /* SO_REUSEPORT */
    }

  // Create an address/port# to bind the socket to. Use mcast_addr to
  // initialize bind_addy to pick up the correct protocol family. If
  // OPT_BINDADDR_YES is set, then we're done. Else use mcast_addr's
  // port number and use the "any" address.
  ACE_INET_Addr bind_addy (mcast_addr);
  if (ACE_BIT_DISABLED (this->opts_, OPT_BINDADDR_YES))
    {
#if defined (ACE_HAS_IPV6)
      if (mcast_addr.get_type () == PF_INET6)
        {
          if (bind_addy.set (mcast_addr.get_port_number (), "::",
                             1, AF_INET6) == -1)
            return -1;
        }
      else
        // Bind to "any" address and explicit port#.
        if (bind_addy.set (mcast_addr.get_port_number ()) == -1)
          return -1;
#else
      // Bind to "any" address and explicit port#.
      if (bind_addy.set (mcast_addr.get_port_number ()) == -1)
        return -1;
#endif /* ACE_HAS_IPV6 */
    }

  // Bind to the address (which may be INADDR_ANY) and port# (which may be 0)
  if (ACE_SOCK_Dgram::shared_open (bind_addy, bind_addy.get_type ()) == -1)
    return -1;

  // Cache the actual bound address (which may be INADDR_ANY)
  // and the actual bound port# (which will be a valid, non-zero port#).
  ACE_INET_Addr bound_addy;
  if (this->get_local_addr (bound_addy) == -1)
    {
      // (Unexpected failure - should be bound to something)
      if (bound_addy.set (bind_addy) == -1)
        {
          // (Shouldn't happen - bind_addy is a valid addy; punt.)
          return -1;
        }
    }

  this->send_addr_ = mcast_addr;
  this->send_addr_.set_port_number (bound_addy.get_port_number ());
  if (net_if)
    {
      if (this->set_nic (net_if, mcast_addr.get_type ()))
        return -1;

      this->send_net_if_ = new ACE_TCHAR[ACE_OS::strlen (net_if) + 1];
      ACE_OS::strcpy (this->send_net_if_, net_if);
    }

  return 0;
}

int
ACE_SOCK_Dgram_Mcast::subscribe_ifs (const ACE_INET_Addr &mcast_addr,
                                     const ACE_TCHAR *net_if,
                                     int reuse_addr)
{
  ACE_TRACE ("ACE_SOCK_Dgram_Mcast::subscribe_ifs");

  if (ACE_BIT_ENABLED (this->opts_, OPT_NULLIFACE_ALL)
      && net_if == 0)
    {
#if defined (ACE_HAS_IPV6)
      if (mcast_addr.get_type () == AF_INET6)
        {
          size_t nr_subscribed = 0;
# if defined(__linux__)
          struct if_nameindex *intf;

          intf = ACE_OS::if_nameindex ();

          if (intf == 0)
            return -1;

          int index = 0;
          while (intf[index].if_index != 0 || intf[index].if_name != 0)
            {
              if (this->join (mcast_addr, reuse_addr,
                              ACE_TEXT_CHAR_TO_TCHAR(intf[index].if_name)) == 0)
                ++nr_subscribed;

              ++index;
            }

          ACE_OS::if_freenameindex (intf);

# elif defined (ACE_WIN32)

          IP_ADAPTER_ADDRESSES tmp_addrs;
          // Initial call to determine actual memory size needed
          DWORD dwRetVal;
          ULONG bufLen = 0;
          if ((dwRetVal = ::GetAdaptersAddresses (AF_INET6,
                                                  0,
                                                  0,
                                                  &tmp_addrs,
                                                  &bufLen)) != ERROR_BUFFER_OVERFLOW)
            return -1; // With output bufferlength 0 this can't be right.

          // Get required output buffer and retrieve info for real.
          PIP_ADAPTER_ADDRESSES pAddrs;
          char *buf;
          ACE_NEW_RETURN (buf,
                          char[bufLen],
                          -1);
          pAddrs = reinterpret_cast<PIP_ADAPTER_ADDRESSES> (buf);
          if ((dwRetVal = ::GetAdaptersAddresses (AF_INET6,
                                                  0,
                                                  0,
                                                  pAddrs,
                                                  &bufLen)) != NO_ERROR)
            {
              delete[] buf; // clean up
              return -1;
            }

          while (pAddrs)
            {
              if (this->join (mcast_addr, reuse_addr,
                              ACE_TEXT_CHAR_TO_TCHAR(pAddrs->AdapterName)) == 0)
                ++nr_subscribed;

              pAddrs = pAddrs->Next;
            }

          delete[] buf; // clean up

# endif /* ACE_WIN32 */

          if (nr_subscribed == 0)
            {
              errno = ENODEV;
              return -1;
            }

          return 1;
        }
      else
        {
          // Subscribe on all local multicast-capable network interfaces, by
          // doing recursive calls with specific interfaces.

          ACE_INET_Addr *if_addrs = 0;
          size_t if_cnt;

          if (ACE::get_ip_interfaces (if_cnt, if_addrs) != 0)
            return -1;

          size_t nr_subscribed = 0;

          if (if_cnt < 2)
            {
              if (this->join (mcast_addr,
                              reuse_addr,
                              ACE_TEXT ("0.0.0.0")) == 0)
                ++nr_subscribed;
            }
          else
            {
              // Iterate through all the interfaces, figure out which ones
              // offer multicast service, and subscribe to them.
              while (if_cnt > 0)
                {
                  --if_cnt;

                  // Convert to 0-based for indexing, next loop check.
                  if (if_addrs[if_cnt].get_type () != AF_INET || if_addrs[if_cnt].is_loopback ())
                    continue;
                  if (this->join (mcast_addr,
                                  reuse_addr,
                                  ACE_TEXT_CHAR_TO_TCHAR
                                   (if_addrs[if_cnt].get_host_addr ())) == 0)
                    ++nr_subscribed;
                }
            }

          delete [] if_addrs;

          if (nr_subscribed == 0)
            {
              errno = ENODEV;
              return -1;
            }

          // 1 indicates a "short-circuit" return.  This handles the
          // recursive behavior of checking all the interfaces.
          return 1;

        }
#else
      // Subscribe on all local multicast-capable network interfaces, by
      // doing recursive calls with specific interfaces.

      ACE_INET_Addr *if_addrs = 0;
      size_t if_cnt;

      if (ACE::get_ip_interfaces (if_cnt, if_addrs) != 0)
        return -1;

      size_t nr_subscribed = 0;

      if (if_cnt < 2)
        {
          if (this->join (mcast_addr,
                          reuse_addr,
                          ACE_TEXT ("0.0.0.0")) == 0)
            ++nr_subscribed;
        }
      else
        {
          // Iterate through all the interfaces, figure out which ones
          // offer multicast service, and subscribe to them.
          while (if_cnt > 0)
            {
              --if_cnt;

              // Convert to 0-based for indexing, next loop check.
              if (if_addrs[if_cnt].is_loopback ())
                continue;
              if (this->join (mcast_addr,
                              reuse_addr,
                              ACE_TEXT_CHAR_TO_TCHAR
                                     (if_addrs[if_cnt].get_host_addr ())) == 0)
                ++nr_subscribed;
            }
        }

      delete [] if_addrs;

      if (nr_subscribed == 0)
        {
          errno = ENODEV;
          return -1;
        }

      // 1 indicates a "short-circuit" return.  This handles the
      // recursive behavior of checking all the interfaces.
      return 1;
#endif /* ACE_HAS_IPV6 */
    }

#if defined (ACE_HAS_IPV6)
  if (mcast_addr.get_type () == AF_INET6)
    {
      if (this->make_multicast_ifaddr6 (0, mcast_addr, net_if) == -1)
        return -1;
    }
  else
    {
      // Validate passed multicast addr and iface specifications.
      if (this->make_multicast_ifaddr (0,
                                       mcast_addr,
                                       net_if) == -1)
        return -1;
    }
#else
    // Validate passed multicast addr and iface specifications.
    if (this->make_multicast_ifaddr (0,
                                     mcast_addr,
                                     net_if) == -1)
      return -1;
#endif /* ACE_HAS_IPV6 */

  return 0;

}

int
ACE_SOCK_Dgram_Mcast::join (const ACE_INET_Addr &mcast_addr,
                            int reuse_addr,
                            const ACE_TCHAR *net_if)
{
  ACE_TRACE ("ACE_SOCK_Dgram_Mcast::join");
  ACE_INET_Addr subscribe_addr = mcast_addr;

  // If port# is 0, insert bound port# if it is set. (To satisfy lower-level
  // port# validation.)
  u_short def_port_number = this->send_addr_.get_port_number ();
  if (subscribe_addr.get_port_number () == 0
      && def_port_number != 0)
    {
      subscribe_addr.set_port_number (def_port_number);
    }

  // Check for port# different than bound port#.
  u_short sub_port_number = mcast_addr.get_port_number ();
  if (sub_port_number != 0
      && def_port_number != 0
      && sub_port_number != def_port_number)
    {
      ACE_ERROR ((LM_ERROR,
                  ACE_TEXT ("Subscribed port# (%u) different than bound ")
                  ACE_TEXT ("port# (%u).\n"),
                  (u_int) sub_port_number,
                  (u_int) def_port_number));
      errno = ENXIO;
      return -1;
    }

  // If bind_addr_opt_ is enabled, check for address different than
  // bound address.
  ACE_INET_Addr tmp_addr (this->send_addr_);
  tmp_addr.set_port_number (mcast_addr.get_port_number ()); // force equal port numbers
  if (ACE_BIT_ENABLED (this->opts_, OPT_BINDADDR_YES)
      && !this->send_addr_.is_any ()
      && this->send_addr_ != mcast_addr)
    {
      ACE_TCHAR sub_addr_string[MAXNAMELEN + 1];
      ACE_TCHAR bound_addr_string[MAXNAMELEN + 1];
      ACE_SDM_helpers::addr_to_string (mcast_addr, sub_addr_string,
                                       sizeof sub_addr_string, 1);
      ACE_SDM_helpers::addr_to_string (this->send_addr_, bound_addr_string,
                                       sizeof bound_addr_string, 1);
      ACE_ERROR ((LM_ERROR,
                  ACE_TEXT ("Subscribed address (%s) different than ")
                  ACE_TEXT ("bound address (%s).\n"),
                  sub_addr_string,
                  bound_addr_string));
      errno = ENXIO;
      return -1;
    }

  // Attempt subscription.
  int result = this->subscribe_i (subscribe_addr, reuse_addr, net_if);

#if defined (ACE_SOCK_DGRAM_MCAST_DUMPABLE)
  if (result == 0)
    {
      // Add this addr/iface info to the list of subscriptions.
      // (Assumes this is unique addr/iface combo - most systems don't allow
      // re-sub to same addr/iface.)
      ip_mreq  *pmreq = new ip_mreq;
      // (should not fail)
      if (this->make_multicast_ifaddr (pmreq, subscribe_addr, net_if) != -1)
        {
          ACE_MT (ACE_GUARD_RETURN (ACE_SDM_LOCK, guard,
                                    this->subscription_list_lock_, -1));
          this->subscription_list_.insert_tail (pmreq);
          return 0;
        }
      // this still isn't really right. If ACE_GUARD_RETURN fails, we leak.
      // Need to add one of Chris' fancy ace auto pointers (bound?).
      delete pmreq;
    }
#endif /* ACE_SOCK_DGRAM_MCAST_DUMPABLE */

  return result >= 0 ? 0 : result;
}

// Attempt subscribe and return status.
int
ACE_SOCK_Dgram_Mcast::subscribe_i (const ACE_INET_Addr &mcast_addr,
                                   int reuse_addr,
                                   const ACE_TCHAR *net_if)
{
  ACE_TRACE ("ACE_SOCK_Dgram_Mcast::subscribe_i");
  ip_mreq  mreq;
#if defined (ACE_HAS_IPV6)
  ipv6_mreq mreq6;
#endif /* __linux__ && ACE_HAS_IPV6 */

  // Open the socket IFF this is the first ::subscribe and ::open
  // was not explicitly invoked.
  if (this->open (mcast_addr,
                  net_if,
                  reuse_addr) == -1)
    return -1;

  // Only do this if net_if == 0, i.e., INADDR_ANY
  if (net_if == 0)
    {
      int result = this->subscribe_ifs (mcast_addr,
                                        net_if,
                                        reuse_addr);
      // Check for error or "short-circuit" return.
      if (result != 0)
        return result;
    }

#if defined (ACE_HAS_IPV6)
  if (mcast_addr.get_type () == AF_INET6)
    {
      if (this->make_multicast_ifaddr6 (&mreq6, mcast_addr, net_if) == -1)
        return -1;
      // Tell IP stack to pass messages sent to this group.
      else if (this->ACE_SOCK::set_option (IPPROTO_IPV6,
                                           IPV6_JOIN_GROUP,
                                           &mreq6,
                                           sizeof mreq6) == -1)
        return -1;

      return 0;
    }
  // Fall through for IPv4 case
#endif /* ACE_HAS_IPV6 */

  // Create multicast addr/if struct.
  if (this->make_multicast_ifaddr (&mreq, mcast_addr, net_if) == -1)
    return -1;
  // Tell IP stack to pass messages sent to this group.
  else if (this->ACE_SOCK::set_option (IPPROTO_IP,
                                       IP_ADD_MEMBERSHIP,
                                       &mreq,
                                       sizeof mreq) == -1)
    return -1;

  return 0;
}

int
ACE_SOCK_Dgram_Mcast::unsubscribe_ifs (const ACE_INET_Addr &mcast_addr,
                                       const ACE_TCHAR *net_if)
{
  ACE_TRACE ("ACE_SOCK_Dgram_Mcast::unsubscribe_ifs");


  if (ACE_BIT_ENABLED (this->opts_, OPT_NULLIFACE_ALL)
      && net_if == 0)
    {
#if defined (ACE_HAS_IPV6)
      if (mcast_addr.get_type () == AF_INET6)
        {
          size_t nr_unsubscribed = 0;
# if defined(__linux__)

          struct if_nameindex *intf;

          intf = ACE_OS::if_nameindex ();

          if (intf == 0)
            return -1;

          int index = 0;
          while (intf[index].if_index != 0 || intf[index].if_name != 0)
            {
              if (this->leave (mcast_addr, ACE_TEXT_CHAR_TO_TCHAR(intf[index].if_name)) == 0)
                ++nr_unsubscribed;

              ++index;
            }

          ACE_OS::if_freenameindex (intf);

# elif defined (ACE_WIN32)

          IP_ADAPTER_ADDRESSES tmp_addrs;
          // Initial call to determine actual memory size needed
          DWORD dwRetVal;
          ULONG bufLen = 0;
          if ((dwRetVal = ::GetAdaptersAddresses (AF_INET6,
                                                  0,
                                                  0,
                                                  &tmp_addrs,
                                                  &bufLen)) != ERROR_BUFFER_OVERFLOW)
            return -1; // With output bufferlength 0 this can't be right.

          // Get required output buffer and retrieve info for real.
          PIP_ADAPTER_ADDRESSES pAddrs;
          char *buf;
          ACE_NEW_RETURN (buf,
                          char[bufLen],
                          -1);
          pAddrs = reinterpret_cast<PIP_ADAPTER_ADDRESSES> (buf);
          if ((dwRetVal = ::GetAdaptersAddresses (AF_INET6,
                                                  0,
                                                  0,
                                                  pAddrs,
                                                  &bufLen)) != NO_ERROR)
            {
              delete[] buf; // clean up
              return -1;
            }

          while (pAddrs)
            {
              if (this->leave (mcast_addr, ACE_TEXT_CHAR_TO_TCHAR(pAddrs->AdapterName)) == 0)
                ++nr_unsubscribed;

              pAddrs = pAddrs->Next;
            }

          delete[] buf; // clean up

# endif /* ACE_WIN32 */

          if (nr_unsubscribed == 0)
            {
              errno = ENODEV;
              return -1;
            }

          return 1;


        }
      else
        {
          // Unsubscribe on all local multicast-capable network interfaces, by
          // doing recursive calls with specific interfaces.

          ACE_INET_Addr *if_addrs = 0;
          size_t if_cnt;

          // NOTE - <get_ip_interfaces> doesn't always get all of the
          // interfaces.  In particular, it may not get a PPP interface.  This
          // is a limitation of the way <get_ip_interfaces> works with
          // old versions of MSVC.  The reliable way of getting the interface
          // list is available only with MSVC 5 and newer.
          if (ACE::get_ip_interfaces (if_cnt, if_addrs) != 0)
            return -1;

          size_t nr_unsubscribed = 0;

          if (if_cnt < 2)
            {
              if (this->leave (mcast_addr,
                               ACE_TEXT ("0.0.0.0")) == 0)
                ++nr_unsubscribed;
            }
          else
            {
              while (if_cnt > 0)
                {
                  --if_cnt;
                  // Convert to 0-based for indexing, next loop check
                  if (if_addrs[if_cnt].get_type () != AF_INET || if_addrs[if_cnt].is_loopback ())
                    continue;
                  if (this->leave (mcast_addr,
                                   ACE_TEXT_CHAR_TO_TCHAR
                                   (if_addrs[if_cnt].get_host_addr ())) == 0)
                    ++nr_unsubscribed;
                }
            }

          delete [] if_addrs;

          if (nr_unsubscribed == 0)
            {
              errno = ENODEV;
              return -1;
            }

          return 1;

        }
#else /* ACE_HAS_IPV6 */
      // Unsubscribe on all local multicast-capable network interfaces, by
      // doing recursive calls with specific interfaces.

      ACE_INET_Addr *if_addrs = 0;
      size_t if_cnt;

      // NOTE - <get_ip_interfaces> doesn't always get all of the
      // interfaces.  In particular, it may not get a PPP interface.  This
      // is a limitation of the way <get_ip_interfaces> works with
      // old versions of MSVC.  The reliable way of getting the interface list
      // is available only with MSVC 5 and newer.
      if (ACE::get_ip_interfaces (if_cnt, if_addrs) != 0)
        return -1;

      size_t nr_unsubscribed = 0;

      if (if_cnt < 2)
        {
          if (this->leave (mcast_addr,
                           ACE_TEXT ("0.0.0.0")) == 0)
            ++nr_unsubscribed;
        }
      else
        {
          while (if_cnt > 0)
            {
              --if_cnt;
              // Convert to 0-based for indexing, next loop check
              if (if_addrs[if_cnt].is_loopback ())
                continue;
              if (this->leave (mcast_addr,
                               ACE_TEXT_CHAR_TO_TCHAR
                               (if_addrs[if_cnt].get_host_addr ())) == 0)
                ++nr_unsubscribed;
            }
        }

      delete [] if_addrs;

      if (nr_unsubscribed == 0)
        {
          errno = ENODEV;
          return -1;
        }

      return 1;
#endif /* !ACE_HAS_IPV6 */
    }

  return 0;
}


int
ACE_SOCK_Dgram_Mcast::leave (const ACE_INET_Addr &mcast_addr,
                             const ACE_TCHAR *net_if)
{
  ACE_TRACE ("ACE_SOCK_Dgram_Mcast::leave");
  // Unsubscribe.
  int result = this->unsubscribe_i (mcast_addr,
                                    net_if);

#if defined (ACE_SOCK_DGRAM_MCAST_DUMPABLE)
  // (Unconditionally) Remove this addr/if from subscription list.
  // (Addr/if is removed even if unsubscribe failed)
  ip_mreq  tgt_mreq;
  if (this->make_multicast_ifaddr (&tgt_mreq,
                                   mcast_addr,
                                   net_if) != -1)
    {
      ACE_MT (ACE_GUARD_RETURN (ACE_SDM_LOCK, guard,
                                this->subscription_list_lock_, -1));
      subscription_list_iter_t iter (this->subscription_list_);
      for (; !iter.done (); iter.advance ())
        {
          ip_mreq  *pm = iter.next ();
          if (ACE_SDM_helpers::is_equal (*pm, tgt_mreq))
            {
              iter.remove ();
              delete pm;
              break;
            }
        }
    }
#endif /* ACE_SOCK_DGRAM_MCAST_DUMPABLE */

  return result >= 0 ? 0 : result;
}

// Attempt unsubscribe and return status.
int
ACE_SOCK_Dgram_Mcast::unsubscribe_i (const ACE_INET_Addr &mcast_addr,
                                     const ACE_TCHAR *net_if)
{
  ACE_TRACE ("ACE_SOCK_Dgram_Mcast::unsubscribe_i");

  int result = this->unsubscribe_ifs (mcast_addr,
                                      net_if);

  // Check for error or "short-circuit" return.
  if (result != 0)
    return result;

#if defined (ACE_HAS_IPV6)
  if (mcast_addr.get_type () == AF_INET6)
    {
      // Validate addr/if specifications and create addr/if struct.
      ipv6_mreq  mreq;
      if (this->make_multicast_ifaddr6 (&mreq, mcast_addr, net_if) == -1)
        {
          return -1;
        }
      // Tell network device driver to stop reading datagrams with the
      // <mcast_addr>.
      else if (ACE_SOCK::set_option (IPPROTO_IPV6,
                                     IPV6_LEAVE_GROUP,
                                     &mreq,
                                     sizeof mreq) == -1)
        {
          return -1;
        }

    }
  else  // IPv4
    {
      // Validate addr/if specifications and create addr/if struct.
      ip_mreq  mreq;
      if (this->make_multicast_ifaddr (&mreq, mcast_addr, net_if) == -1)
        {
          return -1;
        }
      // Tell network device driver to stop reading datagrams with the
      // <mcast_addr>.
      else if (ACE_SOCK::set_option (IPPROTO_IP,
                                     IP_DROP_MEMBERSHIP,
                                     &mreq,
                                 sizeof mreq) == -1)
        {
          return -1;
        }

    }
#else
  // Validate addr/if specifications and create addr/if struct.
  ip_mreq  mreq;
  if (this->make_multicast_ifaddr (&mreq, mcast_addr, net_if) == -1)
    {
      return -1;
    }
  // Tell network device driver to stop reading datagrams with the
  // <mcast_addr>.
  // Note, this is not IPv6 friendly...
  else if (ACE_SOCK::set_option (IPPROTO_IP,
                                 IP_DROP_MEMBERSHIP,
                                 &mreq,
                                 sizeof mreq) == -1)
    {
      return -1;
    }
#endif /* ACE_HAS_IPV6 */

  return 0;
}

int
ACE_SOCK_Dgram_Mcast::clear_subs_list (void)
{
  ACE_TRACE ("ACE_SOCK_Dgram_Mcast::clear_subs_list");
  int result = 0;

#if defined (ACE_SOCK_DGRAM_MCAST_DUMPABLE)
  ACE_MT (ACE_GUARD_RETURN (ACE_SDM_LOCK, guard,
                            this->subscription_list_lock_, -1));
  subscription_list_iter_t iter (this->subscription_list_);
  for (; !iter.done (); /*Hack: Do _not_ ::advance after remove*/)
    {
      ip_mreq  *pm = iter.next ();
      iter.remove ();
      delete pm;
    }
#endif /* ACE_SOCK_DGRAM_MCAST_DUMPABLE */
  return result;
}

ACE_END_VERSIONED_NAMESPACE_DECL

---