mirror of https://github.com/dirtbags/moth.git
92 lines
2.5 KiB
HTML
92 lines
2.5 KiB
HTML
<!DOCTYPE html>
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<html>
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<head>
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<title>Welcome</title>
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<link rel="stylesheet" href="../ctf.css" type="text/css">
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</head>
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<body>
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<h1>Moo.</h1>
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<p>
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You are trying to guess a 4-nybble sequence. Each nybble will have
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either 1 or 2 bits set, and the highest bit will never be set. The
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game server will tell you how many nybbles in each guess were correct,
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and how many had one correct bit. It does not tell you which
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positions.
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</p>
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<h2>The Cow Client</h2>
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<p>
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<a href="cowcli">Download the client</a>
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</p>
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<p>
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The client connects to the Cow server running on the IPv6
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address provided in argument 1. The client reads a guess
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in the form of 4 ASCII numerals, and prints the number of
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correct nybbles followed by the number of nybbles with one
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correct bit.
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</p>
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<p>
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Here is an example of a session:
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</p>
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<pre>
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1111
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12
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2222
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10
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4444
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02
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4244
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12
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1244
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22
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1255
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moo:xylep-radar-nanox
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</pre>
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<p>
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You can use a program like <samp>socat</samp> to connect
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the client to a logic program you write:
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</p>
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<pre>
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socat EXEC:"./cowcli fd84:b410:3441::ec6" EXEC:./mysolution
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</pre>
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<p>
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This will allow your program to read and write from stdio
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of the client program.
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</p>
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<h2>The Cow Protocol</h2>
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<p>
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cowd runs on port 3782 on fd84:b410:3441::ec6.
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</p>
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<p>
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The client always sends 6 octets. To request a new session, it sends
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all zeroes. Otherwise it sends the 4-octet game identifier provided
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by the server, concatenated with a 2-octet guess.
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</p>
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<p>
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The server will respond with a new game identifier (4 octets) to a new
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game request or if the game requested is too old. If a guess is
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incorrect, the server will respond with either a 1-octet score in
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which the high nybble is the number of correct nybbles in the guess,
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and the low nybble is the number of nybbles in the guess with one
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correct bit. If a guess is correct, the server will respond with a
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token of length 5 octets or more.
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</p>
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<p>
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There are multiple tokens, one per number of guesses used, up to
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some maximum number of guesses defined per server instance.
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</p>
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</body>
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</html>
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