Defines the ACE socket wrapper for UDP/IP multicast. More...

#include <SOCK_Dgram_Mcast.h>

Inheritance diagram for ACE_SOCK_Dgram_Mcast:

Collaboration diagram for ACE_SOCK_Dgram_Mcast:

Public Types
enum	options { OPT_BINDADDR_NO = 0, OPT_BINDADDR_YES = 1, DEFOPT_BINDADDR = OPT_BINDADDR_NO, OPT_NULLIFACE_ONE = 0, OPT_NULLIFACE_ALL = 2, DEFOPT_NULLIFACE = OPT_NULLIFACE_ALL, DEFOPTS = DEFOPT_BINDADDR \| DEFOPT_NULLIFACE }
	Option parameters. More...
Public Member Functions
	ACE_SOCK_Dgram_Mcast (options opts=DEFOPTS)
	~ACE_SOCK_Dgram_Mcast (void)
int	open (const ACE_INET_Addr &mcast_addr, const ACE_TCHAR *net_if=0, int reuse_addr=1)
int	join (const ACE_INET_Addr &mcast_addr, int reuse_addr=1, const ACE_TCHAR *net_if=0)
int	leave (const ACE_INET_Addr &mcast_addr, const ACE_TCHAR *net_if=0)
ssize_t	send (const void *buf, size_t n, int flags=0) const
ssize_t	send (const iovec iov[], int n, int flags=0) const
int	set_option (int option, char optval)
	Set a socket option.
void	dump (void) const
	Dump the state of an object.
Public Attributes
	ACE_ALLOC_HOOK_DECLARE
	Declare the dynamic allocation hooks.
Protected Member Functions
int	open_i (const ACE_INET_Addr &mcast_addr, const ACE_TCHAR *net_if=0, int reuse_addr=1)
int	clear_subs_list (void)
	Empty the dynamic subscription list.
Private Member Functions
int	subscribe_ifs (const ACE_INET_Addr &mcast_addr, const ACE_TCHAR *net_if, int reuse_addr)
int	subscribe_i (const ACE_INET_Addr &mcast_addr, int reuse_addr=1, const ACE_TCHAR *net_if=0)
int	unsubscribe_ifs (const ACE_INET_Addr &mcast_addr, const ACE_TCHAR *net_if=0)
	Unsubscribe from a multicast address on one or more network interface(s).
int	unsubscribe_i (const ACE_INET_Addr &mcast_addr, const ACE_TCHAR *net_if=0)
Private Attributes
int	opts_
	Per-instance options..
ACE_INET_Addr	send_addr_
	Multicast address to which local send() methods send datagrams.
ACE_TCHAR *	send_net_if_
	Network interface to which all send() methods send multicast datagrams.

Detailed Description

Defines the ACE socket wrapper for UDP/IP multicast.

Supports multiple simultaneous subscriptions, unsubscription from one or all subscriptions, and independent send/recv address and interface specifications. Template parameters and/or ctor arguments determine per-instance optional functionality.

Note that multicast semantics and implementation details are _very_ environment-specific; this class is just a wrapper around the underlying implementation and does not try to normalize the concept of multicast communications.

Usage Notes:

Send and Recv addresses and network interfaces, but not port#, are independent. While this instance is open, 1 send interface (and a default send address) is in effect and 0, 1, or multiple recv addresses/interfaces are in effect.
The first open()/subscribe() invocation defines the network interface and default address used for all sends by this instance, defines the port# and optionally the multicast address bound to the underlying socket, and defines the (one) port# that is used for all subscribes (subsequent subscribes must pass the same port# or '0').
The default loopback state is not explicitly set; the environment will determine the default state. Note that some environments (e.g. some Win32) do not allow the default to be changed, and that the semantics of loopback control are environment dependent (e.g. sender vs receiver control).
In general, due to multicast design and implementation quirks/bugs, it is difficult to tell which address a received message was sent to or which interface it was received on (even if only one subscription is active). However; there are filtering options that can be applied, to narrow it down considerably.

Interface specification notes (for subscribe() and unsubscribe()):

If net_if == 0, the null_iface_opt option determines whether only the system "default" interface or all interfaces is affected. Specifying "all" interfaces is supported only for environments for which ACE_Sock_Connect::get_ip_interfaces() is properly implemented.
Multiple subscriptions for the same address but different interfaces is normally supported, but re-subscription to an address/interface that is already subscribed is normally not allowed.
The <net_if> interface specification syntax is environment-specific. UNIX systems will normally use device specifications such as "le0" or "elxl1", while other systems will use the IP address of the interface. Some platforms, such as pSoS, support only cardinal numbers as network interface specifications; for these platforms, just give these numbers in alphanumeric form and <subscribe> will convert them into numbers via ACE_OS::atoi().

Member Enumeration Documentation

enum ACE_SOCK_Dgram_Mcast::options

Option parameters.

These control per-instance optional functionality. They are set via optional constructor arguments.

Note:: Certain option values are not valid for all environments (see comments in source file for environment-specific restrictions). Default values are always valid values for the compilation environment.

Enumerator:

OPT_BINDADDR_NO	Disable address bind. (Bind only port.) Note: This might seem odd, but we need a way to distinguish between default behavior, which might or might not be to bind, and explicitly choosing to bind or not to bind--which "is the question." ;-)
OPT_BINDADDR_YES	Enable address bind. (Bind port and address.)
DEFOPT_BINDADDR	Default value for BINDADDR option. (Environment-dependent.) At least some Win32 OS's can not bind mcast addr, so disable it. General-purpose default behavior is 'disabled', since effect is environment-specific and side-effects might be surprising.
OPT_NULLIFACE_ONE	Define the interpretation of 'NULL' as a recv interface specification. If the interface part of a multicast address specification is NULL, it will be interpreted to mean either "the default interface" or "all interfaces", depending on the setting of this option. Notes: The 'nulliface_all' option can not be used in environments which do not fully support the ACE_Sock_Connect::get_ip_interfaces() method (e.g. non-Windows). If it is, using NULL for iface will _always_ fail. The default behavior in most IP stacks is to use the 'default' interface, where 'default' has rather ad-hoc semantics. This applies only to receives, not sends (which always use only one interface; NULL means use the "system default" interface). Supported values: If (net_if==NULL), use default interface. Note: This might seem odd, but we need a way to distinguish between default behavior, which might or might not be to bind, and explicitly choosing to bind or not to bind--which "is the question." ;-)
OPT_NULLIFACE_ALL	If (net_if==NULL), use all mcast interfaces.
DEFOPT_NULLIFACE	Default value for NULLIFACE option. (Environment-dependent.) This is the (ad-hoc) legacy behavior for Win32/WinSock. Note: Older version of WinSock/MSVC may not get all multicast-capable interfaces (e.g. PPP interfaces).
DEFOPTS	All default options.

Constructor & Destructor Documentation

ACE_SOCK_Dgram_Mcast::ACE_SOCK_Dgram_Mcast ( ACE_SOCK_Dgram_Mcast::options opts = DEFOPTS )

Ctor - Create an unitialized instance and define per-instance optional functionality. You must invoke open() or subscribe(), to create/bind a socket and define operational parameters, before performing any I/O with this instance.

ACE_SOCK_Dgram_Mcast::~ACE_SOCK_Dgram_Mcast ( void )

Dtor - Release all resources and implicitly or explicitly unsubscribe from all currently subscribed groups. The OPT_DTORUNSUB_YES_ option defines whether an explicit unsubscribe() is done by the destructor. If not, most systems will automatically unsubscribe upon the close of the socket.

Member Function Documentation

int ACE_SOCK_Dgram_Mcast::clear_subs_list ( void ) [protected]

Empty the dynamic subscription list.

void ACE_SOCK_Dgram_Mcast::dump ( void ) const

Dump the state of an object.

Logs the setting of all options, the bound address, the send address and interface, and the list of current subscriptions.

Reimplemented from ACE_SOCK_Dgram.

int ACE_SOCK_Dgram_Mcast::join	(	const ACE_INET_Addr &	mcast_addr,
		int	reuse_addr = `1`,
		const ACE_TCHAR *	net_if = `0`
	)

Join a multicast group on a given interface (or all interfaces, if supported). The given group is joined on the specified interface. If option OPT_NULLIFACE_ALL is used and net_if is = 0, the group is joined on all multicast capable interfaces (IFF supported). Multiple subscriptions to various address and interface combinations are supported and tracked. If this is the first invocation of subscribe(), and open() was not previously invoked, open() will be invoked using mcast_addr for binding the socket and net_if as the interface for send().

Returns: -1 if the call fails. Failure can occur due to problems with the address, port#, and/or interface parameters or during the subscription attempt. Once bind() has been invoked (by the first open() or subscribe()), returns errno of ENXIO if the port# is not 0 and does not match the bound port#, or if OPT_BINDADDR_YES option is used and the address does not match the bound address. Returns errno of ENODEV if the addr/port#/interface parameters appeared valid, but no subscription(s) succeeded. An error is unconditionally returned if option OPT_NULLIFACE_ALL is used, net_if is NULL, and ACE_Sock_Connect::get_ip_interfaces() is not implemented in this environment.

Note that the optional reuse_addr parameter does not apply to subscriptions; it is only used if open() is implicitly invoked (see above).

Uses the mcast_addr to determine protocol_family, and protocol which we always pass as 0 anyway.

int ACE_SOCK_Dgram_Mcast::leave	(	const ACE_INET_Addr &	mcast_addr,
		const ACE_TCHAR *	net_if = `0`
	)

Leave a multicast group on a given interface (or all interfaces, if supported). The specified group/interface combination is unsubscribed. If option OPT_NULLIFACE_ALL is used and net_if is = 0, the group is unsubscribed from all interfaces (IFF supported).

Returns: -1 if the unsubscribe failed. Most environments will return -1 if there was no active subscription for this address/interface combination. An error is unconditionally returned if option OPT_NULLIFACE_ALL is used, net_if is = 0, and ACE_Sock_Connect::get_ip_interfaces() is not implemented in this environment (_even if_ the subscribe() specifies a non- NULL net_if).

leave() replaces unsubscribe() and uses mcast_addr to determine protocol_family, and protocol which we always pass as 0 anyway.

int ACE_SOCK_Dgram_Mcast::open	(	const ACE_INET_Addr &	mcast_addr,
		const ACE_TCHAR *	net_if = `0`,
		int	reuse_addr = `1`
	)

Explicitly open/bind the socket and define the network interface and default multicast address used for sending messages. This method is optional; if not explicitly invoked, it is invoked by the first subscribe(), using the subscribed address/port# and network interface parameters. The mcast_addr parameter defines the default send address/port# and also the port# and, if the OPT_BINDADDR_YES option is used, the multicast address that is bound to this socket. If the net_if parameter != 0, it defines the network interface used for all sends by this instance, otherwise the system "default" interface is used. (The net_if parameter is ignored if this feature is not supported by the environment.) The port# in mcast_addr may be 0, in which case a system-assigned (ephemeral) port# is used for sending and receiving. If reuse_addr != 0, the SO_REUSEADDR option and, if it is supported, the SO_REUSEPORT option are enabled.

Returns: -1 if the call fails. Failure can occur due to problems with the address, port#, and/or interface parameters or during system open() or socket option processing.

int ACE_SOCK_Dgram_Mcast::open_i	(	const ACE_INET_Addr &	mcast_addr,
		const ACE_TCHAR *	net_if = `0`,
		int	reuse_addr = `1`
	)		`[protected]`

Contains common open functionality so that inheriting classes can reuse it.

ssize_t ACE_SOCK_Dgram_Mcast::send	(	const void *	buf,
		size_t	n,
		int	flags = `0`
	)		const `[inline]`

Send n bytes in buf, using the multicast address and network interface defined by the first open() or subscribe().

ssize_t ACE_SOCK_Dgram_Mcast::send	(	const iovec	iov[],
		int	n,
		int	flags = `0`
	)		const `[inline]`

Send n iovecs, using the multicast address and network interface defined by the first open() or subscribe().

int ACE_SOCK_Dgram_Mcast::set_option	(	int	option,
		char	optval
	)		`[inline]`

Set a socket option.

Set an IP option that takes a char as input, such as IP_MULTICAST_LOOP or IP_MULTICAST_TTL. This is just a more concise, nice interface to a subset of possible ACE_SOCK::set_option calls, but only works for IPPROTO_IP or IPPROTO_IPV6 level options.

Returns 0 on success, -1 on failure.

Deprecated:: This method has been deprecated since it cannot be used easily with with IPv6 options. Use ACE_SOCK::set_option instead.

int ACE_SOCK_Dgram_Mcast::subscribe_i	(	const ACE_INET_Addr &	mcast_addr,
		int	reuse_addr = `1`,
		const ACE_TCHAR *	net_if = `0`
	)		`[private]`

Do subscription processing w/out updating the subscription list. (Layered method for <subscribe> processing).

int ACE_SOCK_Dgram_Mcast::subscribe_ifs	(	const ACE_INET_Addr &	mcast_addr,
		const ACE_TCHAR *	net_if,
		int	reuse_addr
	)		`[private]`

Subscribe to a multicast address on one or more network interface(s). (No QoS support.)

int ACE_SOCK_Dgram_Mcast::unsubscribe_i	(	const ACE_INET_Addr &	mcast_addr,
		const ACE_TCHAR *	net_if = `0`
	)		`[private]`

Do unsubscription processing w/out udpating subscription list. (Layered method for <unsubscribe> processing).

int ACE_SOCK_Dgram_Mcast::unsubscribe_ifs	(	const ACE_INET_Addr &	mcast_addr,
		const ACE_TCHAR *	net_if = `0`
	)		`[private]`

Unsubscribe from a multicast address on one or more network interface(s).

Member Data Documentation

ACE_SOCK_Dgram_Mcast::ACE_ALLOC_HOOK_DECLARE

Declare the dynamic allocation hooks.

Reimplemented from ACE_SOCK_Dgram.

int ACE_SOCK_Dgram_Mcast::opts_ [private]

Per-instance options..

ACE_INET_Addr ACE_SOCK_Dgram_Mcast::send_addr_ [private]

Multicast address to which local send() methods send datagrams.

ACE_TCHAR* ACE_SOCK_Dgram_Mcast::send_net_if_ [private]

Network interface to which all send() methods send multicast datagrams.

The documentation for this class was generated from the following files:

Public Types

Public Member Functions

Public Attributes

Protected Member Functions

Private Member Functions

Private Attributes

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation