From: Will Sobel Date: 2001-08-01T09:05:56+09:00 Subject: [ruby-talk:18925] RE: IP multicast with UDPSocket This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. ------_=_NextPart_001_01C11A1F.2CECF680 Content-Type: text/plain; charset="iso-8859-1" Something I threw together a few weeks ago. It has only been tested using Ruby 1.7.1 on Win32, but It should work on the other platforms as well. You may have to take out the definition of the constants since they should already be defined in socket.c. There are some some differences in the C headers #defines of these constants, but I did not have time to look into this and fix it on Windows. enjoy... - Will require 'socket' #struct ip_mreq { # struct in_addr imr_multiaddr; /* IP multicast address of group */ # struct in_addr imr_interface; /* local IP address of interface */ #}; class MulticastSocket < UDPSocket # Some constants that are not set in Win32 version of socket.c IPPROTO_IP = 0 IPPROTO_UDP = 17 IP_DROP_MEMBERSHIP = 6 def convAddr(a) h = nil case a when String h = a.split('.').collect! { |b| b.to_i }.pack('CCCC') when Array h = a.pack('CCCC') else raise "Bad address" end h end private :convAddr def addMembership(mcaddr) mreq = convAddr(mcaddr) + Socket.gethostbyname(Socket.gethostname)[3] setsockopt(IPPROTO_IP, Socket::IP_ADD_MEMBERSHIP, mreq) end def dropMembership(mcaddr) mreq = convAddr(mcaddr) + Socket.gethostbyname(Socket.gethostname)[3] setsockopt(IPPROTO_IP, IP_DROP_MEMBERSHIP, mreq) end def setMCTTL(ttl) setsockopt(IPPROTO_IP, Socket::IP_MULTICAST_TTL, ttl) end def setMCLoop(loop) setsockopt(IPPROTO_IP, Socket::IP_MULTICAST_LOOP, loop) end def setMCInterface(int) host = Socket.gethostbyname(int)[3] setsockopt(IPPROTO_IP, Socket::IP_MULTICAST_IF, host) end end if $0 == __FILE__ $port = 1900 $addr = '239.192.0.1' sock = MulticastSocket.open sock.bind(Socket.gethostname, $port) sock.addMembership($addr) thread = Thread.start do 2.times { p sock.recvfrom(8000) } end sock.send('Hello', 0, $addr, $port) sock.send('There', 0, $addr, $port) thread.join sock.dropMembership($addr) end -----Original Message----- From: Nat Pryce [mailto:nat.pryce@b13media.com] Sent: Tuesday, July 31, 2001 5:09 AM To: ruby-talk@ruby-lang.org Subject: [ruby-talk:18883] IP multicast with UDPSocket Does anyone have example code for joining/leaving multicast groups using the UDPSocket? Also, how is it possible to write this in a platform independent manner? As far as I can tell, the API for setting socket options seems to be completely platform dependent. It is also hard to code to, because you have to build strings of binary data that contain valid C structures used by the OS APIs. Would there be interest in code to replace or wrap setsockopt/getsockopt with methods and attribute accessors? For example: socket = UDPSocket.new socket.add_membership "240.212.100.200" # or whatever a valid IP group number is socket.ip_multicast_ttl = Socket::TTL_LOCAL_NETWORK socket.ip_multicast_loopback = false socket.sol_reuse_address = true socket.bind( 15630 ) Or: socket = TCPSocket.new( 'www.b13media.com', 80 ) socket.sol_sndbuf = 512 socket.sol_rcvbuf = 4096 Would this be a useful RCR? Cheers, Nat. ------_=_NextPart_001_01C11A1F.2CECF680 Content-Type: text/html; charset="iso-8859-1"

Something I threw together a few weeks ago. It has only been tested using Ruby 1.7.1 on Win32, but It should work on the other platforms as well. You may have to take out the definition of the constants since they should already be defined in socket.c. There are some some differences in the C headers #defines of these constants, but I did not have time to look into this and fix it on Windows.

enjoy...

- Will

require 'socket'

#struct ip_mreq {
# struct in_addr imr_multiaddr; /* IP multicast address of group */
# struct in_addr imr_interface; /* local IP address of interface */
#};

class MulticastSocket < UDPSocket

# Some constants that are not set in Win32 version of socket.c
IPPROTO_IP = 0
IPPROTO_UDP = 17
IP_DROP_MEMBERSHIP = 6

def convAddr(a)
  h = nil
  case a
  when String
   h = a.split('.').collect! { |b| b.to_i }.pack('CCCC')

when Array
h = a.pack('CCCC')

  else
   raise "Bad address"
  end
  h
end
private :convAddr

def addMembership(mcaddr)
  mreq = convAddr(mcaddr) + Socket.gethostbyname(Socket.gethostname)[3]
  setsockopt(IPPROTO_IP, Socket::IP_ADD_MEMBERSHIP, mreq)
end

def dropMembership(mcaddr)
mreq = convAddr(mcaddr) + Socket.gethostbyname(Socket.gethostname)[3]
setsockopt(IPPROTO_IP, IP_DROP_MEMBERSHIP, mreq)
end

def setMCTTL(ttl)
setsockopt(IPPROTO_IP, Socket::IP_MULTICAST_TTL, ttl)
end

def setMCLoop(loop)
setsockopt(IPPROTO_IP, Socket::IP_MULTICAST_LOOP, loop)
end

def setMCInterface(int)
host = Socket.gethostbyname(int)[3]
setsockopt(IPPROTO_IP, Socket::IP_MULTICAST_IF, host)
end

end

if $0 == __FILE__

$port = 1900
$addr = '239.192.0.1'

sock = MulticastSocket.open
sock.bind(Socket.gethostname, $port)
sock.addMembership($addr)

thread = Thread.start do
2.times { p sock.recvfrom(8000) }
end

sock.send('Hello', 0, $addr, $port)
sock.send('There', 0, $addr, $port)

thread.join
sock.dropMembership($addr)
end

</SNIP>

-----Original Message-----
From: Nat Pryce [mailto:nat.pryce@b13media.com]
Sent: Tuesday, July 31, 2001 5:09 AM
To: ruby-talk@ruby-lang.org
Subject: [ruby-talk:18883] IP multicast with UDPSocket

Does anyone have example code for joining/leaving multicast groups using the UDPSocket?

Also, how is it possible to write this in a platform independent manner? As far as I can tell, the API for setting socket options seems to be completely platform dependent. It is also hard to code to, because you have to build strings of binary data that contain valid C structures used by the OS APIs. Would there be interest in code to replace or wrap setsockopt/getsockopt with methods and attribute accessors?

For example:

socket = UDPSocket.new

socket.add_membership "240.212.100.200" # or whatever a valid IP group number is

socket.ip_multicast_ttl = Socket::TTL_LOCAL_NETWORK

socket.ip_multicast_loopback = false

socket.sol_reuse_address = true

socket.bind( 15630 )

Or:

socket = TCPSocket.new( 'www.b13media.com', 80 )

socket.sol_sndbuf = 512

socket.sol_rcvbuf = 4096

Would this be a useful RCR?

Cheers,

Nat.

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