README.rtnetproxy
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===================
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08-Nov-2002, Mathias Koehrer <mathias_koehrer@yahoo.de>
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02-May-2008, Wolfgang Grandegger <wg@grandegger.com>
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RTnetproxy can be used to share a single network adapter for both - realtime
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and non-realtime ethernet traffic. TCP/IP, UDP and ARP can be used via RTnet
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(of course not in realtime!)
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RTnetproxy represents a network device to standard Linux and can be used
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as any other Linux network device (ifconfig for configuration), the name
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the network device is "rtproxy".
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Setup:
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--------
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Get your RTnet working first! All IP addresses you are interested in have
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to be set via "rtifconfig ethX route solicit IP_ADDRESS"!
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insmod rtnetproxy.o
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Now, you have a network device "rtproxy" ready to be used with Linux.
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Configure this network device using "ifconfig":
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Example:
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ifconfig rtproxy up 192.168.10.10 netmask 255.255.255.0
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That's it!
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Configuration options:
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------------------------
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--enable-proxy: this enables RTnetproxy support, which is by default
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restricted to IP-based protocols (TCP/IP!!!). Incoming frames from
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ICMP are interpreted directly by RTnet and are not forwarded to the
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RTnetproxy. UDP packets are forwarded if they are not requested by
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an RTnet application.
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--enable-proxy-arp: this option enables ARP support for the rtproxy Linux
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network device. Incoming ARP replys are delivered to both, the RTnet
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and the Linux network stack. The rtproxy then gets attached to the
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corresponding RTnet device, rteth0 by default.
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--disable-icmp: this option disables the RTnet IPv4 ICMP support. ICMP
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will then be handled by the Linux network stack via the rtproxy Linux
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network device.
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Important note:
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-----------------
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It is highly recommended to strictly separate realtime LAN traffic and non-
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realtime LAN traffic. For a configuration/setup phase, TCP/IP is sometimes
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very useful, buf for realtime data exchange the LAN should be reserved for
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the realtime traffic using UDP!
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How it works internally:
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--------------------------
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RTnetproxy works on top of RTnet.
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All data to be sent out or received is actually copied between RTnet and
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RTnetproxy => The performance is not as good as with the standard Linux
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network drivers.
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All incoming IPv4 frames, having a IP protocol ID that is not handled by
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RTnet are passed to RTnetproxy.
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Incoming frames, that are passed to RTnetproxy (TCP frames) slow down the
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realtime stuff a little bit - as all this is done in realtime mode context!
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Possible enhancements:
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-----------------------
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Pass incoming frames to RTnetproxy not only by checking the protocol ID but
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by actual checking, if a certain frame has been processed by RTnet or not.
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This leads to a couple of changes in the RTnet implementation...
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