Multicast socket API

net/udp/udp_socket_libevent.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_UDP_UDP_SOCKET_LIBEVENT_H_
 #define NET_UDP_UDP_SOCKET_LIBEVENT_H_
 
+#include "base/hash_tables.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "base/threading/non_thread_safe.h"
 #include "net/base/completion_callback.h"
 #include "net/base/net_export.h"
 #include "net/base/rand_callback.h"
 #include "net/base/io_buffer.h"
 #include "net/base/ip_endpoint.h"
 #include "net/base/net_log.h"
@@ skipping 88 matching lines @@
   // Sets corresponding flags in |socket_options_| to allow the socket
   // to share the local address to which the socket will be bound with
   // other processes. Should be called before Bind().
   void AllowAddressReuse();
 
   // Sets corresponding flags in |socket_options_| to allow sending
   // and receiving packets to and from broadcast addresses. Should be
   // called before Bind().
   void AllowBroadcast();
 
+  // Join the multicast group.
+  // |group_address| is the group address to join, could be either
+  // IPv4 or IPv6 address.
+  int JoinGroup(const net::IPAddressNumber& group_address) const;
+
+  // Leave the multicast group.
+  // |group_address| is the group address to leave, could be either
+  // IPv4 or IPv6 address. If the socket hasn't joined the group,
+  // it will be ignored.
+  // It's optional to leave the multicast group before destroying
+  // the socket. It will be done by the OS.
+  int LeaveGroup(const net::IPAddressNumber& group_address) const;
+
+  // Set the time-to-live option for udp packets sent to the multicast
+  // group address. Initially this value is 1. Cannot be negative or
+  // more than 255.
+  int SetMulticastTimeToLive(int time_to_live);

[mmenke, 2013/04/16 18:09:49]

Think it's worth mentioned that this is safe to call either before or after the
socket is bound.

[Bei Zhang, 2013/04/17 17:53:03]

Please see comments in udp_socket_libevent.cc
On 2013/04/16 18:09:49, mmenke wrote:

+
+  // Set the loopback flag for udp socket. If this flag is true, the host
+  // will receive package sent to the joined group from itself.
+  // Initially this value is true.
+  int SetMulticastLoopbackMode(bool loopback);
+
  private:
   static const int kInvalidSocket = -1;
 
   enum SocketOptions {
     SOCKET_OPTION_REUSE_ADDRESS = 1 << 0,
     SOCKET_OPTION_BROADCAST     = 1 << 1
   };
 
   class ReadWatcher : public MessageLoopForIO::Watcher {
    public:
@@ skipping 55 matching lines @@
   int InternalRecvFrom(IOBuffer* buf, int buf_len, IPEndPoint* address);
   int InternalSendTo(IOBuffer* buf, int buf_len, const IPEndPoint* address);
 
   // Applies |socket_options_| to |socket_|. Should be called before
   // Bind().
   int SetSocketOptions();
   int DoBind(const IPEndPoint& address);
   int RandomBind(const IPEndPoint& address);
 
   int socket_;
+  int sock_addr_family_;
 
   // Bitwise-or'd combination of SocketOptions. Specifies the set of
   // options that should be applied to |socket_| before Bind().
   int socket_options_;
 
+  // Multicast socket options cached for SetSocketOption.
+  // Cannot be used after Bind().
+  int multicast_time_to_live_;
+  bool multicast_loopback_mode_;
+
   // How to do source port binding, used only when UDPSocket is part of
   // UDPClientSocket, since UDPServerSocket provides Bind.
   DatagramSocket::BindType bind_type_;
 
   // PRNG function for generating port numbers.
   RandIntCallback rand_int_cb_;
 
   // These are mutable since they're just cached copies to make
   // GetPeerAddress/GetLocalAddress smarter.
   mutable scoped_ptr<IPEndPoint> local_address_;
@@ skipping 24 matching lines @@
   CompletionCallback write_callback_;
 
   BoundNetLog net_log_;
 
   DISALLOW_COPY_AND_ASSIGN(UDPSocketLibevent);
 };
 
 }  // namespace net
 
 #endif  // NET_UDP_UDP_SOCKET_LIBEVENT_H_