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diff --git a/contrib/t2hproxy/README b/contrib/t2hproxy/README deleted file mode 100644 index ce5e1e9b..00000000 --- a/contrib/t2hproxy/README +++ /dev/null @@ -1,95 +0,0 @@ -T2hproxy - -This is a TFTP to HTTP proxy. To the TFTP client it looks like a TFTP -server. To the HTTP server it looks like a HTTP client. So you can store -your boot files on the HTTP server. Or even create them with a CGI -program. E.g. if you can get dhcpd to send a filename which has strings -representing attributes of the client, as determined from the DHCP -request, then you can get the CGI program to parse this and send the -appropriate image, which might even be synthesised. - -There are two versions of the proxy, in Perl and in Java. - -1. The Perl version. - -This is the original quick Perl hack conceived in a moment of madness. -:-) Perl is great for prototyping. - -To run it, you need Perl 5.8.0 or later and all the Perl modules listed -at the top of the program installed. Edit and install the xinetd config -file as /etc/xinetd.d/t2hproxy and restart xinetd. The prefix is the -string that is prepended to all filenames to form the URL requested from -the HTTP server. Remember you need the trailing / if the filenames don't -start with /. - -This is only a proof-of concept. It has these drawbacks at the moment: - -+ (I don't consider this a draback, but some may.) It's started from -xinetd because xinetd handles all the socket listening, IP address -checking, rate limiting, etc. - -+ It has no cache. Use a proxy to do the caching (there's a --proxy -option). This also takes care of fetching from outside a firewall. - -+ It reads the entire HTTP content into memory before serving. Ideally -it should stream it from the HTTP server to minimise memory usage. This -is a serious drawback for booting lots of clients. Each instance of the -server will consume an amount of memory equal to the size of image -loaded. - -+ If the HTTP server is at the end of a slow link there is a delay -before the first data block is sent. The client may timeout before -then. Another reason for streaming, as this allows the first block to -be sent sooner. A local cache primed with the images in advance may -help. Using the blocksize option helps here because this causes the -server to send the OACK to the client immediately before the data is -fetched and this prevents it from starting up another connection. - -+ The transfer size may not be obtainable from the HTTP headers in all -cases, e.g. a CGI constructed image. This matters for clients that need -the tsize extension, which is not supported at the moment. - -If I'm feeling masochistic I may write a Java version, which should take -care of the multi-threading and streaming. - -2. The Java version - -The main problem with the Perl version is that it does not stream the -HTTP input but sucks it all in at once. As mentioned, this causes a -delay as well as requiring memory to hold the image. I could fix this by -doing the polling on the HTTP socket myself instead of letting LWP do -it, but that's for later. Java has streaming facilities as well as -threading and is also somewhat portable. So I decided to be masochistic -and give it a go. But boy is Java bureaucratic. - -You will need a Java 1.4 JRE, because I use the java.nio classes; and -the commons-httpclient and commons-logging jars from the -jakarta.apache.org project. As I understand it, there are several ways -to get those jars on your classpath. One is to put it in the directory -where your java extensions jars are kept, normally -$JAVA_HOME/jre/lib/ext. But it may not be writable to you. Another is to -set your $CLASSPATH variable to have those jars in the path. A third is -to use the -cp option of the java interpreter, see the shell script -runT2hproxy for details. - -All the source is in one Java file. build.xml is a "Makefile" for ant to -compile and jar it. You should then edit runT2proxy.sh as required, then -start it. As with the Perl version, the prefix is what's prepended to -the filenames requested by the TFTP client, and the proxy is the -host:port string for the proxy if you are using one. On *ix you will -need root permission to listen on ports below 1024 (TFTP is at 69 UDP by -default). - -Currently it logs to stderr, but you can change this by downloading and -installing the log4j jar from jakarta.apache.org and instructing -commons-logging to use that, with a command line property setting and a -property file. Destinations could be syslog, or a file, or an event -logger, or...; it's supposedly very flexible. - -3. Licensing - -All this code is GPLed. For details read the file COPYING found in the -Etherboot top directory since it currently bundled with Etherboot. I -don't see the point of including COPYING in every directory. - -Ken Yap, October 2003 |