50 lines
1.7 KiB
Plaintext
50 lines
1.7 KiB
Plaintext
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Asynchronous DNS
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Intro.
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For those who write real time network applications that have to handle
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multiple TCP or UDP connections, the problem of effectively doing DNS
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lookups is quite real. Generally, this means the program waits while
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the query finishes, holding everything else up. This small library of
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routines aims to solve that problem by performing the DNS query and
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then returning the program to its normal flow.
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Whats included ?
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The library routines, arlib.c, a header file for it, arlib.h, a man
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page, arlib.3 and an example of how this sort of code is used,
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sample.c.
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Compilation & Installation.
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Edit the Makefile and do "make install" to install things where you
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wish them to go. You should check it makes and works before doing
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this :)
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If the compilation is successful, you'll have an executeable called
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"example" and libares.a. "example" is a simple program which will
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do hostname->IP# or IP#->hostnae lookups by entering either the
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hostname or IP# on the line with "Host-->". You dont have to wait
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for a query to fail or succeed before typing in the next line.
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Portability.
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I'm not sure how portable this is, it was written under SunOS 4.1.2
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on a Sparc 1+ and hasn't been tested very widely. If you find any
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problems when compiling/execution, plase send me a patch (using
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diff -c) to avalon@coombs.anu.edu.au. If it goes well enough, I'll
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send it to comp.unix.sources or comp.sources.misc for further testing.
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Future additions.
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Adding a working cache would be nice but I'm not sure if that really
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is needed (?). I guess it depends on how often your program is
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required to do a DNS lookup and whether caching would help.
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Cheers,
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Darren.
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