From: Farrel Lifson <flifson@...>
Date: 2002-04-29T01:36:04+09:00
Subject: Inconsistent network behaviour

Hi all,

I'm a Ruby newbie when it comes to network programming so while writing
a little example to teach myself it I came across this rather
inconsistent behaviour. Firstly here are my two scripts. One is a server
which listens on a port and the other a client which sends it simple
messages.

#client.rb
require "socket"
session = TCPSocket.new("localhost",5179)
session.send("INVITE sip:you@bar.com SIP/2.0\n",0)
session.send("From: me@foo.com\n",0)
session.send("To: you@bar.com\n",0)
session.send("\r\n",0)
session.close

#server.rb
require "socket" 
def parse_header(socket)
	data = ""
	connec = Hash.new
  	while (data != "\r\n")
		data = socket.recv(1000)
		print "Data read: ",data
		property,value = data.split(/: /)
		connec[property]=value
	end
	connec
end
server = TCPServer.new("localhost",5179)
while (session=server.accept)
  	connection = Hash.new
	data = session.recv(100)
	if (data.split)[0] == "INVITE"	
  		connection = parse_header(session)	
	end
end

When I run the server on my Linux box (Mandrake 8.1, Kernel 2.4.8, Ruby
1.6.4) I get the desired output:

Data read: me@foo.com
Data read: you@bar.com

When I run it on a FreeBSD box (FreeBSD 4.4,Ruby 1.6.3) the output is:

Data read: me@foo.com
To: you@bar.com

The program reads the two lines (sent using two seperate send method
calls) in with one recv, as well as the final "\r\n" which causes it to
then go into an infinite loop (printing out Data read: Data read: Data
read: ...) as it keeps on reading in from the socket even though it is
closed on the client side. 

This is a simple exercise so I'm sure there's a solution, just that I
can't find anything in the pickaxe book or online docs. Any ideas what
the problem is and why the behaviour is different on Linux and FreeBSD?

Thanks in advance,
Farrel Lifson
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