site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com -josh On Jun 1, 2006, at 11:38 AM, Josh Graessley wrote: -josh On Jun 1, 2006, at 11:09 AM, Terry Lambert wrote: _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.a... This email sent to site_archiver@lists.apple.com I missed one other point. If the UDP socket is connected, the stack will use both the source and destination addresses and port to locate the socket. Actually, each socket has it's own receive buffer. The stack will only deliver unicast packets to the first socket that matches based on destination address and port. The definition of the "first socket that matches" is a little vague. On Mac OS X, this is the first socket bound to the port. This is very implementation specific. For multicast packets, the stack goes out of its way to deliver a copy of the packet to every socket. I see from your email address that you work for Asperasoft, makers of FASP, which uses UDP instead of TCP for large file transfers over high latency/packet loss links to avoid the bandwidth delay product issue, having to support huge TCP windows, or having to implement rate based ACK or TCP rate halving (e.g. CMU's experimental replacement for Nagle et. al.) in the native networking stack of the OS you are running on. With that in mind, I have to question the validity of doing this as multiple users. I can understand wanting to do this on "this is the machine" basis, but on a per-user basis, the only valid reason for this would be transmission; there's no guarantee that any given packet would end up going to the right user process on receive, since only the address of the socket differentiates inbound packets to the UDP stack: there'd only be one socket receive buffer associated with it, and whoever read first would get the data, which is probably not what you want, if you're trying to use different user identities to do privilege separation to avoid disclosure of one user's packet contents to another user. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/jgraessley% 40apple.com This email sent to jgraessley@apple.com smime.p7s