70 lines
1.5 KiB
Bash
Executable File
70 lines
1.5 KiB
Bash
Executable File
#!/bin/zsh
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read bytes
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echo "bytes:" > /dev/stderr
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echo $bytes | hexdump -C > /dev/stderr
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readarray -t data <<< $(echo -n $bytes | hexdump -e '/1 "%u\n"')
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echo "data:" > /dev/stderr
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echo ${data[@]} | hexdump -C > /dev/stderr
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echo "FIN bit:" $(( ${data[0]} >> 7 )) > /dev/stderr
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echo "opcode:" $(( ${data[0]} & 0x0f )) > /dev/stderr
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echo ${data[0]} > /dev/stderr
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mask_bit=$(( ${data[1]} >> 7 ))
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echo "Mask (bit):" $mask_bit > /dev/stderr
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len=$(( ${data[1]} & 0x7f ))
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offset=2 # 2 for header
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if [[ $len == 126 ]]; then
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len=$(( ${data[2]} << 8 + ${data[3]} ))
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offset=4 # 2 for header, 2 for extended length
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elif [[ $len == 127 ]]; then
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len=0
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for i in {0..8}; do
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len=$(( $len << 8 + ${data[2+i]} ))
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done
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offset=10 # 2 for header, 8 for extended length
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fi
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echo "Data length:" $len > /dev/stderr
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echo "Offset:" $offset > /dev/stderr
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if [[ $mask_bit == 1 ]]; then
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read -ra mask <<< ${data[@]:$offset:4}
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echo "Mask:" $mask > /dev/stderr
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offset=$(( $offset + 4 ))
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fi
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read -ra payload <<< ${data[@]:$offset:$len}
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echo "Payload:" ${payload[@]} > /dev/stderr
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if [[ $mask_bit == 1 ]]; then
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for ((i = 0; i < $len; i++)); do
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byte=$(( ${payload[$i]} ^ ${mask[$i % 4]} ))
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echo "Byte $i: $byte" > /dev/stderr
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payload[$i]=$byte
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done
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echo "Payload unmasked:" ${payload[@]} > /dev/stderr
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fi
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payload_hex=""
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for ((i = 0; i < $len; i++)); do
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hex=$(printf '\\x%x\n' $(( ${payload[$i]} )))
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payload_hex+=$hex
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done
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echo "Payload hex:" $payload_hex > /dev/stderr
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echo -e "Payload: $payload_hex" > /dev/stderr
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