Multicast socket API

net/udp/udp_socket_libevent.cc

 // 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.
 
 #include "net/udp/udp_socket_libevent.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <netdb.h>
 #include <sys/socket.h>
@@ skipping 23 matching lines @@
 }  // namespace net
 
 namespace net {
 
 UDPSocketLibevent::UDPSocketLibevent(
     DatagramSocket::BindType bind_type,
     const RandIntCallback& rand_int_cb,
     net::NetLog* net_log,
     const net::NetLog::Source& source)
         : socket_(kInvalidSocket),
-          socket_options_(0),
+          addr_family_(0),
+          socket_options_(SOCKET_OPTION_MULTICAST_LOOP),
+          multicast_time_to_live_(1),
           bind_type_(bind_type),
           rand_int_cb_(rand_int_cb),
           read_watcher_(this),
           write_watcher_(this),
           read_buf_len_(0),
           recv_from_address_(NULL),
           write_buf_len_(0),
           net_log_(BoundNetLog::Make(net_log, NetLog::SOURCE_UDP_SOCKET)) {
   net_log_.BeginEvent(NetLog::TYPE_SOCKET_ALIVE,
                       source.ToEventParametersCallback());
@@ skipping 301 matching lines @@
         CreateNetLogUDPDataTranferCallback(
             result, bytes,
             is_address_valid ? &address : NULL));
   }
 
   base::StatsCounter read_bytes("udp.read_bytes");
   read_bytes.Add(result);
 }
 
 int UDPSocketLibevent::CreateSocket(const IPEndPoint& address) {
-  socket_ = socket(address.GetSockAddrFamily(), SOCK_DGRAM, 0);
+  addr_family_ = address.GetSockAddrFamily();
+  socket_ = socket(addr_family_, SOCK_DGRAM, 0);
   if (socket_ == kInvalidSocket)
     return MapSystemError(errno);
   if (SetNonBlocking(socket_)) {
     const int err = MapSystemError(errno);
     Close();
     return err;
   }
   return OK;
 }
 
@@ skipping 92 matching lines @@
       return MapSystemError(errno);
   }
   if (socket_options_ & SOCKET_OPTION_BROADCAST) {
     int rv;
 #if defined(OS_MACOSX)
     // SO_REUSEPORT on OSX permits multiple processes to each receive
     // UDP multicast or broadcast datagrams destined for the bound
     // port.
     rv = setsockopt(socket_, SOL_SOCKET, SO_REUSEPORT, &true_value,
                     sizeof(true_value));
-    if (rv < 0)
-      return MapSystemError(errno);
-#endif  // defined(OS_MACOSX)
+#else
     rv = setsockopt(socket_, SOL_SOCKET, SO_BROADCAST, &true_value,
                     sizeof(true_value));
+#endif  // defined(OS_MACOSX)
     if (rv < 0)
       return MapSystemError(errno);
   }
+
+  if (!(socket_options_ & SOCKET_OPTION_MULTICAST_LOOP)) {
+      uint8 loop = 0;

[wtc, 2013/04/17 22:06:50]

BUG: it seems that this variable needs to be a u_int for
IPv6. See http://lists.ntp.org/pipermail/bugs/2011-May/013564.html
and
http://publib.boulder.ibm.com/infocenter/zos/v1r13/index.jsp?topic=%2Fcom.ibm...

[Bei Zhang, 2013/04/19 19:40:14]

Done. Now we use different branches for IPv4 and IPv6 so the following problems
are prevented.

On 2013/04/17 22:06:50, wtc wrote:

+      int ip_family =

[wtc, 2013/04/17 22:06:50]

This variable should be named 'level' or 'protocol_level'
instead of 'ip_family'.
See http://pubs.opengroup.org/onlinepubs/009695399/functions/setsockopt.html

Make the same change to line 502.

[Bei Zhang, 2013/04/19 19:40:14]

Done.

+          addr_family_ == AF_INET ? IPPROTO_IP : IPPROTO_IPV6;
+      int option =
+          addr_family_ == AF_INET ? IP_MULTICAST_LOOP: IPV6_MULTICAST_LOOP;
+      int rv = setsockopt(socket_, ip_family, option, &loop, sizeof(loop));
+      if (rv < 0)
+        return MapSystemError(errno);
+  }
+  if (multicast_time_to_live_ != IP_DEFAULT_MULTICAST_TTL) {
+    uint8 ttl = multicast_time_to_live_;
+    int ip_family =
+        addr_family_ == AF_INET ? IPPROTO_IP : IPPROTO_IPV6;
+    int option =
+        addr_family_ == AF_INET ? IP_MULTICAST_TTL: IP_MULTICAST_TTL;

[wtc, 2013/04/17 22:06:50]

BUG?: I think we need to use IPV6_MULTICAST_HOPS for IPv6.
Note that IPV6_MULTICAST_HOPS uses an 'int' for its option
value, according to
http://publib.boulder.ibm.com/infocenter/zos/v1r13/index.jsp?topic=%2Fcom.ibm...

[Bei Zhang, 2013/04/19 19:40:14]

Done.

+    int rv = setsockopt(socket_, ip_family, option, &ttl, sizeof(ttl));
+    if (rv < 0)
+      return MapSystemError(errno);
+  }
   return OK;
 }
 
 int UDPSocketLibevent::DoBind(const IPEndPoint& address) {
   SockaddrStorage storage;
   if (!address.ToSockAddr(storage.addr, &storage.addr_len))
     return ERR_UNEXPECTED;
   int rv = bind(socket_, storage.addr, storage.addr_len);
   return rv < 0 ? MapSystemError(errno) : rv;
 }
 
 int UDPSocketLibevent::RandomBind(const IPEndPoint& address) {
   DCHECK(bind_type_ == DatagramSocket::RANDOM_BIND && !rand_int_cb_.is_null());
 
   // Construct IPAddressNumber of appropriate size (IPv4 or IPv6) of 0s.
   IPAddressNumber ip(address.address().size());
 
   for (int i = 0; i < kBindRetries; ++i) {
     int rv = DoBind(IPEndPoint(ip, rand_int_cb_.Run(kPortStart, kPortEnd)));
     if (rv == OK || rv != ERR_ADDRESS_IN_USE)
       return rv;
   }
   return DoBind(IPEndPoint(ip, 0));
 }
 
+int UDPSocketLibevent::JoinGroup(const IPAddressNumber& group_address) const {
+  DCHECK(CalledOnValidThread());
+  DCHECK(is_connected());
+
+  switch (group_address.size()) {
+    case kIPv4AddressSize: {
+      if (addr_family_ != AF_INET)
+        return ERR_ADDRESS_INVALID;
+      ip_mreq mreq;
+      mreq.imr_interface.s_addr = INADDR_ANY;
+      memcpy(&mreq.imr_multiaddr, &group_address[0], kIPv4AddressSize);
+      int rv = setsockopt(socket_, IPPROTO_IP, IP_ADD_MEMBERSHIP,
+                          &mreq, sizeof(mreq));
+      if (rv < 0)
+        return MapSystemError(errno);
+      return OK;
+    }
+    case kIPv6AddressSize: {
+      if (addr_family_ != AF_INET6)
+        return ERR_ADDRESS_INVALID;
+      ipv6_mreq mreq;
+      mreq.ipv6mr_interface = 0;  // 0 indicates default multicast interface.
+      memcpy(&mreq.ipv6mr_multiaddr, &group_address[0], kIPv6AddressSize);
+      int rv = setsockopt(socket_, IPPROTO_IPV6, IPV6_JOIN_GROUP,
+                          &mreq, sizeof(mreq));
+      if (rv < 0)
+        return MapSystemError(errno);
+      return OK;
+    }
+    default:
+      NOTREACHED() << "Invalid address family";
+      return ERR_ADDRESS_INVALID;
+  }
+}
+
+int UDPSocketLibevent::LeaveGroup(const IPAddressNumber& group_address) const {
+  DCHECK(CalledOnValidThread());
+  DCHECK(is_connected());
+
+  switch (group_address.size()) {
+    case kIPv4AddressSize: {
+      if (addr_family_ != AF_INET)
+        return ERR_ADDRESS_INVALID;
+      ip_mreq mreq;
+      mreq.imr_interface.s_addr = INADDR_ANY;
+      memcpy(&mreq.imr_multiaddr, &group_address[0], kIPv4AddressSize);
+      int rv = setsockopt(socket_, IPPROTO_IP, IP_DROP_MEMBERSHIP,
+                          &mreq, sizeof(mreq));
+      if (rv < 0)
+        return MapSystemError(errno);
+      return OK;
+    }
+    case kIPv6AddressSize: {
+      if (addr_family_ != AF_INET6)
+        return ERR_ADDRESS_INVALID;
+      ipv6_mreq mreq;
+      mreq.ipv6mr_interface = 0;  // 0 indicates default multicast interface.
+      memcpy(&mreq.ipv6mr_multiaddr, &group_address[0], kIPv6AddressSize);
+      int rv = setsockopt(socket_, IPPROTO_IPV6, IPV6_LEAVE_GROUP,
+                          &mreq, sizeof(mreq));
+      if (rv < 0)
+        return MapSystemError(errno);
+      return OK;
+    }
+    default:
+      NOTREACHED() << "Invalid address family";
+      return ERR_ADDRESS_INVALID;
+  }
+}
+
+int UDPSocketLibevent::SetMulticastTimeToLive(int time_to_live) {
+  DCHECK(CalledOnValidThread());
+  DCHECK(!is_connected());
+  if (time_to_live < 0 || time_to_live > 255)
+    return ERR_INVALID_ARGUMENT;
+  multicast_time_to_live_ = time_to_live;
+  return OK;
+}
+
+int UDPSocketLibevent::SetMulticastLoopbackMode(bool loopback) {
+  DCHECK(CalledOnValidThread());
+  DCHECK(!is_connected());
+  if (loopback)
+    socket_options_ |= SOCKET_OPTION_MULTICAST_LOOP;
+  else
+    socket_options_ &= ~SOCKET_OPTION_MULTICAST_LOOP;
+  return OK;
+}
 }  // namespace net