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# ACE_SOCK_Dgram_Mcast Class Reference

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

`#include <SOCK_Dgram_Mcast.h>`

Inheritance diagram for ACE_SOCK_Dgram_Mcast:

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Collaboration diagram for ACE_SOCK_Dgram_Mcast:

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List of all members.

## 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 Methods
| ACE_SOCK_Dgram_Mcast (options opts=DEFOPTS)
| Ctor - Create an unitialized instance and define per-instance optional functionality. More...
| ~ACE_SOCK_Dgram_Mcast (void)
| Dtor - Release all resources and implicitly or explicitly unsubscribe from all currently subscribed groups. More...
int | 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. More...
int | subscribe (const ACE_INET_Addr &mcast_addr, int reuse_addr=1, const ACE_TCHAR *net_if=0, int protocol_family=PF_INET, int protocol=0)
| Join a multicast group on a given interface (or all interfaces, if supported). More...
int | join (const ACE_INET_Addr &mcast_addr, int reuse_addr=1, const ACE_TCHAR *net_if=0)
int | unsubscribe (const ACE_INET_Addr &mcast_addr, const ACE_TCHAR *net_if=0, int protocol_family=PF_INET, int protocol=0)
| Leave a multicast group on a given interface (or all interfaces, if supported). More...
int | leave (const ACE_INET_Addr &mcast_addr, const ACE_TCHAR *net_if=0)
int | unsubscribe (void)
| Unsubscribe all current subscriptions. More...
ssize_t | send (const void *buf, size_t n, int flags=0) const
| Send <n> bytes in <buf>, using the multicast address and network interface defined by the first <open> or <subscribe>. More...
ssize_t | send (const iovec iov[], int n, int flags=0) const
| Send <n> <iovecs>, using the multicast address and network interface defined by the first <open> or <subscribe>. More...
int | set_option (int option, char optval)
| Set a socket option. More...
void | dump (void) const
| Dump the state of an object. More...
## Public Attributes
| ACE_ALLOC_HOOK_DECLARE
| Declare the dynamic allocation hooks. More...
## Protected Methods
int | open_i (const ACE_INET_Addr &mcast_addr, const ACE_TCHAR *net_if=0, int reuse_addr=1)
| Contains common open functionality so that inheriting classes can reuse it. More...
int | make_multicast_ifaddr (ip_mreq *mreq, const ACE_INET_Addr &mcast_addr, const ACE_TCHAR *net_if)
| Create a multicast addr/if pair, in format useful for system calls. If mreq param is NULL, just verify the passed addr/interface specs. More...
int | make_multicast_ifaddr_i (ip_mreq *mreq, const ACE_INET_Addr &mcast_addr, const ACE_TCHAR *net_if=ACE_LIB_TEXT("le0"))
| Create a multicast addr/if pair. This method factors out common code called by <make_multicast_address> and <subscribe>. More...
int | clear_subs_list (void)
| Empty the dynamic subscription list. More...
## Private Methods
int | subscribe_ifs (const ACE_INET_Addr &mcast_addr, const ACE_TCHAR *net_if, int reuse_addr)
| Subscribe to a multicast address on one or more network interface(s). (No QoS support.). More...
int | subscribe_i (const ACE_INET_Addr &mcast_addr, int reuse_addr=1, const ACE_TCHAR *net_if=0)
| Do subscription processing w/out updating the subscription list. More...
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). More...
int | unsubscribe_i (const ACE_INET_Addr &mcast_addr, const ACE_TCHAR *net_if=0)
| Do unsubscription processing w/out udpating subscription list. More...
## Private Attributes
int | opts_
| Per-instance options.. More...
ACE_INET_Addr | send_addr_
| Multicast address to which local <send> methods send datagrams. More...
ACE_TCHAR * | send_net_if_
| Network interface to which all <send> methods send multicast datagrams. More...

## 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. Enumeration values:
  OPT_BINDADDR_NO | Disable address bind. (Bind only port.).
  OPT_BINDADDR_YES | Enable address bind. (Bind port and address.).
  DEFOPT_BINDADDR | Default value for BINDADDR option. (Environment-dependent.).
  OPT_NULLIFACE_ONE | If (net_if==NULL), use default interface.
  OPT_NULLIFACE_ALL | If (net_if==NULL), use all mcast interfaces.
  DEFOPT_NULLIFACE | Default value for NULLIFACE option. (Environment-dependent.).
  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 <unsusbcribe> 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
| ) |

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

int ACE_SOCK_Dgram_Mcast::make_multicast_ifaddr | ( | ip_mreq * | ret_mreq,
|  | const ACE_INET_Addr & | mcast_addr,
|  | const ACE_TCHAR * | net_if
| ) | `[protected]`

| Create a multicast addr/if pair, in format useful for system calls. If mreq param is NULL, just verify the passed addr/interface specs.

int ACE_SOCK_Dgram_Mcast::make_multicast_ifaddr_i | ( | ip_mreq * | mreq,
|  | const ACE_INET_Addr & | mcast_addr,
|  | const ACE_TCHAR * | net_if = ACE_LIB_TEXT ("le0")
| ) | `[protected]`

| Create a multicast addr/if pair. This method factors out common code called by <make_multicast_address> and <subscribe>.

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 paramters. 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 <send_net_if> parameter != 0, it defines the network interface used for all sends by this instance, otherwise the system "default" interface is used. (The <send_net_if> parameter is ignored if this feature is not supported by the envriornment.) 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.

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

| Send <n> <iovecs>, using the multicast address and network interface defined by the first <open> or <subscribe>.

ASYS_INLINE ssize_t ACE_SOCK_Dgram_Mcast::send | ( | const void * | buf,
|  | size_t | n,
|  | int | flags = 0
| ) | const

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

ASYS_INLINE int ACE_SOCK_Dgram_Mcast::set_option | ( | int | option,
|  | char | optval
| ) |

| 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. Use <ACE_SOCK::set_option> directly to set anything else. Deprecated: { This method has been deprecated since it cannot be used easily with with IPv6 options.} Returns 0 on success, -1 on failure.

int ACE_SOCK_Dgram_Mcast::subscribe | ( | const ACE_INET_Addr & | mcast_addr,
|  | int | reuse_addr = 1,
|  | const ACE_TCHAR * | net_if = 0,
|  | int | protocol_family = PF_INET,
|  | int | protocol = 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). NOTICE - This method has been deprecated, please use join() instead. In addition, the following paramters have also been deprecated: <protocol_family> and <protocol> have no effect.

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.

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 | ( | void |  | ) |

| Unsubscribe all current subscriptions. Unsubscribe all active group/interface subscriptions (if any). Returns -1 if any unsubscribe failed, 0 if there are no errors or no current subscriptions. This method has been deprecated. Since a list of groups is not maintained (except when ACE_SOCK_DGRAM_MCAST_DUMPABLE is defined), it isn't possible to unsubscribe to all the groups without closing the socket. Therefore, if applications wish to unsubscribe to all groups without closing the socket, they much keep track of the subscriptions and call the above unsubscribe () for each.

int ACE_SOCK_Dgram_Mcast::unsubscribe | ( | const ACE_INET_Addr & | mcast_addr,
|  | const ACE_TCHAR * | net_if = 0,
|  | int | protocol_family = PF_INET,
|  | int | protocol = 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>). NOTICE - This method has been deprecated. Please use leave() instead. In addition, <protocol_family> and <protocol> have no effect.

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.

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:

- SOCK_Dgram_Mcast.h
- SOCK_Dgram_Mcast.cpp
- SOCK_Dgram_Mcast.i