112 lines
3.7 KiB
Ruby
112 lines
3.7 KiB
Ruby
module NSCA
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class <<self
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def xor key, msg, key_a = nil
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key_a ||= key.unpack 'C*'
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l = key_a.length
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return msg if l < 1
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# Slice the message in parts of length key_a.length.
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# XOR each char of a part with char at the same index in key_a.
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msg.unpack( 'C*').each_with_index.map {|c,i| c^key_a[i%l] }.pack 'C*'
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end
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def crc32 msg
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(msg.each_byte.inject 0xFFFFFFFF do |r,b|
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8.times.inject( r^b) {|r,_i| (r>>1) ^ (0xEDB88320 * (r&1)) }
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end) ^ 0xFFFFFFFF
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end
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# Builds a null terminated, null padded string of length maxlen
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def str2cstr( str, maxlen = nil)
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str = str.to_s
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str = str.to_s[0..(maxlen-2)] if maxlen
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"#{str}\x00"
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end
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def cstr2str( str, maxlen = nil) str[ 0, x.index( ?\0) || ((maxlen||0)-1)] end
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end
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class Packet
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class CSC32CheckFailed <Exception
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end
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class VersionCheckFailed <Exception
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end
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def self.versions version = nil
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@@versions ||= {}
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version ? @@versions[version] : @@versions
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end
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def self.register_version( version, klass) versions[version] = klass end
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# @param [Time,Integer,nil] timestamp Checked at this time
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# @param [0..3] return_code `NSCA::ReturnCode`
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# @param [String(length<64),nil] hostname If nil, local hostname will be used.
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# Must be known by Nagios.
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# @param [String(length<128)] service Name of Service. Must be known by Nagios.
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# @param [String(length<512)] status Status-line inclusive optional Performance Data.
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def initialize timestamp, return_code, hostname, service, status
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@timestamp, @return_code, @hostname, @service, @status =
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Time.at( timestamp.to_f), return_code, hostname, service, status
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end
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attr_accessor :timestamp, :return_code, :hostname, :service, :status
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end
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class PacketV3 < Packet
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NAGIOS_VERSION = 2.7
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PACKET_VERSION = 3
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END_OF_TRANSMISSION = ?\x0a
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HOSTNAME_LENGTH = 64
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SERVICE_LENGTH = 128
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STATUS_LENGTH = 512
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# these line describes the data package:
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# typedef struct data_packet_struct{
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# int16_t packet_version;
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# /* two padding bytes (because aligning): xx */
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# u_int32_t crc32_value;
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# u_int32_t timestamp;
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# int16_t return_code;
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# char host_name[MAX_HOSTNAME_LENGTH];
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# char svc_description[MAX_DESCRIPTION_LENGTH];
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# char plugin_output[MAX_PLUGINOUTPUT_LENGTH];
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# /* two extra padding-xx, too. */
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# }data_packet;
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PACK_STRING = "s> xx L> L> s> Z#{HOSTNAME_LENGTH} Z#{SERVICE_LENGTH} Z#{STATUS_LENGTH} xx"
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PACK_LENGTH = 2+2+4+4+2+HOSTNAME_LENGTH+SERVICE_LENGTH+STATUS_LENGTH+2
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register_version PACKET_VERSION, self
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# Builds a check-result-line for NSCA.
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#
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# Will be terminated by end-of-terminate.
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def build key = nil, password = nil
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entry = [
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PACKET_VERSION,
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0, # crc32 (unknown yet)
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(timestamp || Time.now).to_i,
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return_code.to_i,
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NSCA::str2cstr( hostname || `hostname -f`, HOSTNAME_LENGTH),
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NSCA::str2cstr( service, SERVICE_LENGTH),
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NSCA::str2cstr( status, STATUS_LENGTH) # incl perfdata
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]
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# generate crc32 and put it at entry[2...6]
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entry[1] = NSCA::crc32 entry.pack( PACK_STRING)
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entry = entry.pack PACK_STRING
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entry = NSCA::xor key, entry if key
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entry = NSCA::xor password, entry if password
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entry
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end
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def self.parse entry, key = nil, password = nil, no_verification_checks = nil
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entry = NSCA::xor key, entry if key
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entry = NSCA::xor password, entry if password
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ver, crc32sum, *x = entry.unpack( PACK_STRING)
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raise VersionCheckFailed, "Packet version 3 expected. (recv: #{ver})" \
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unless no_verification_checks or 3 == ver
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entry[4..7] = ?\x00*4
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raise CSC32CheckFailed, "crc32-check failed. packet seems to be broken." \
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unless no_verification_checks or crc32sum == NSCA::crc32( entry)
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new *x
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end
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end
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end
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