Tod Beardsley
f1950c2fe1
Fixes #3289. This commit adds back the bit-struct library because in the end, it is useful for some modules, especially pello's. It's small and it has a nice license, so why not. After all, it /is/ useful for quicky application headers. Eventually, should be replaced by StructFu, but that requires some doc work on my part to get that transition in place. This also adds pello's DNS fuzzer module which makes use of BitStruct to create sometimes malformed-on-purpose DNS headers. Tested against 3 different DNS servers, caused one to reboot, so I'd say it works.
45 lines
1.2 KiB
Ruby
45 lines
1.2 KiB
Ruby
class BitStruct
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# Class for null-terminated printable text strings.
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# Declared with BitStruct.text.
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class TextField < Field
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# Used in describe.
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def self.class_name
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@class_name ||= "text"
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end
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def add_accessors_to(cl, attr = name) # :nodoc:
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unless offset % 8 == 0
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raise ArgumentError,
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"Bad offset, #{offset}, for #{self.class} #{name}." +
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" Must be multiple of 8."
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end
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unless length % 8 == 0
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raise ArgumentError,
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"Bad length, #{length}, for #{self.class} #{name}." +
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" Must be multiple of 8."
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end
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offset_byte = offset / 8
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length_byte = length / 8
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last_byte = offset_byte + length_byte - 1
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byte_range = offset_byte..last_byte
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val_byte_range = 0..length_byte-1
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cl.class_eval do
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define_method attr do ||
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self[byte_range].sub(/\0*$/, "").to_s
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end
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define_method "#{attr}=" do |val|
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val = val.to_s
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if val.length < length_byte
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val += "\0" * (length_byte - val.length)
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end
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self[byte_range] = val[val_byte_range]
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end
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end
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end
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end
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end
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