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#!/bin/bash
# Copyright 2021 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
[ -n "${network_init-}" ] && return
mac_to_bytes() {
local -n bytes="$1"
local str="$2"
# Verify that the MAC is Valid
[[ "$str" =~ ^[[:xdigit:]]{1,2}(:[[:xdigit:]]{1,2}){5}$ ]] || return
# Split the mac into hex bytes
local oldifs="$IFS"
IFS=:
local byte
for byte in $str; do
bytes+=(0x$byte)
done
IFS="$oldifs"
}
mac_to_eui48() {
local mac_bytes=(0 0 0 0 0 0 0 0 0 0)
mac_to_bytes mac_bytes "$1" || return
# Return the EUI-64 bytes in the IPv6 format
ip_bytes_to_str mac_bytes
}
mac_to_eui64() {
local mac_bytes=()
mac_to_bytes mac_bytes "$1" || return
# Using EUI-64 conversion rules, create the suffix bytes from MAC bytes
# Invert bit-0 of the first byte, and insert 0xfffe in the middle.
local suffix_bytes=(
0 0 0 0 0 0 0 0
$((mac_bytes[0] ^ 1))
${mac_bytes[@]:1:2}
$((0xff)) $((0xfe))
${mac_bytes[@]:3:3}
)
# Return the EUI-64 bytes in the IPv6 format
ip_bytes_to_str suffix_bytes
}
ip_to_bytes() {
local -n bytes_out="$1"
local str="$2"
local bytes=()
local oldifs="$IFS"
# Heuristic for V4 / V6, validity will be checked as it is parsed
if [[ "$str" == *.* ]]; then
# Ensure we don't start or end with IFS
[ "${str:0:1}" != '.' ] || return 1
[ "${str: -1}" != '.' ] || return 1
local v
# Split IPv4 address into octets
IFS=.
for v in $str; do
# IPv4 digits are always decimal numbers
if ! [[ "$v" =~ ^[0-9]+$ ]]; then
IFS="$oldifs"
return 1
fi
# Each octet is a single byte, make sure the number isn't larger
if (( v > 0xff )); then
IFS="$oldifs"
return 1
fi
bytes+=($v)
done
# IPv4 addresses must have all 4 bytes present
if (( "${#bytes[@]}" != 4 )); then
IFS="$oldifs"
return 1
fi
else
# Ensure we bound the padding in an outer byte for
# IFS splitting to work correctly
[ "${str:0:2}" = '::' ] && str="0$str"
[ "${str: -2}" = '::' ] && str="${str}0"
# Ensure we don't start or end with IFS
[ "${str:0:1}" != ':' ] || return 1
[ "${str: -1}" != ':' ] || return 1
# Stores the bytes that come before ::, if it exists
local bytesBeforePad=()
local v
# Split the Address into hextets
IFS=:
for v in $str; do
# Handle ::, which translates to an empty string
if [ -z "$v" ]; then
# Only allow a single :: sequence in an address
if (( "${#bytesBeforePad[@]}" > 0 )); then
IFS="$oldifs"
return 1
fi
# Store the already parsed upper bytes separately
# This allows us to calculate and insert padding
bytesBeforePad=("${bytes[@]}")
bytes=()
continue
fi
# IPv6 digits are always hex
if ! [[ "$v" =~ ^[[:xdigit:]]+$ ]]; then
IFS="$oldifs"
return 1
fi
# Ensure the number is no larger than a hextet
v="0x$v"
if (( v > 0xffff )); then
IFS="$oldifs"
return 1
fi
# Split the hextet into 2 bytes
bytes+=($(( v >> 8 )))
bytes+=($(( v & 0xff )))
done
# If we have ::, add padding
if (( "${#bytesBeforePad[@]}" > 0 )); then
# Fill the middle bytes with padding and store in `bytes`
while (( "${#bytes[@]}" + "${#bytesBeforePad[@]}" < 16 )); do
bytesBeforePad+=(0)
done
bytes=("${bytesBeforePad[@]}" "${bytes[@]}")
fi
# IPv6 addresses must have all 16 bytes present
if (( "${#bytes[@]}" != 16 )); then
IFS="$oldifs"
return 1
fi
fi
IFS="$oldifs"
bytes_out=("${bytes[@]}")
}
ip_bytes_to_str() {
local -n bytes="$1"
if (( "${#bytes[@]}" == 4 )); then
printf '%d.%d.%d.%d\n' "${bytes[@]}"
elif (( "${#bytes[@]}" == 16 )); then
# Track the starting position of the longest run of 0 hextets (2 bytes)
local longest_i=0
# Track the size of the longest run of 0 hextets
local longest_s=0
# The index of the first 0 byte in the current run of zeros
local first_zero=0
local i
# Find the location of the longest run of zero hextets, preferring same
# size runs later in the address.
for (( i=0; i<=16; i+=2 )); do
# Terminate the run of zeros if we are at the end of the array or
# have a non-zero hextet
if (( i == 16 || bytes[$i] != 0 || bytes[$((i+1))] != 0 )); then
local s=$((i - first_zero))
if (( s >= longest_s )); then
longest_i=$first_zero
longest_s=$s
fi
first_zero=$((i+2))
fi
done
# Build the address string by each hextet
for (( i=0; i<16; i+=2 )); do
# If we encountered a run of zeros, add the necessary :: at the end
# of the string. If not at the end, a single : is added since : is
# printed to subsequent hextets already.
if (( i == longest_i )); then
(( i += longest_s-2 ))
printf ':'
# End of string needs to be ::
if (( i == 14 )); then
printf ':'
fi
else
# Prepend : to all hextets except the first for separation
if (( i != 0 )); then
printf ':'
fi
printf '%x' $(( (bytes[$i]<<8) | bytes[$(($i+1))]))
fi
done
printf '\n'
else
echo "Invalid IP Bytes: ${bytes[*]}" >&2
return 1
fi
}
ip_pfx_concat() {
local pfx="$1"
local sfx="$2"
# Parse the prefix
if ! [[ "$pfx" =~ ^([0-9a-fA-F:.]+)/([0-9]+)$ ]]; then
echo "Invalid IP prefix: $pfx" >&2
return 1
fi
local addr="${BASH_REMATCH[1]}"
local cidr="${BASH_REMATCH[2]}"
# Ensure prefix doesn't have too many bytes
local pfx_bytes=()
if ! ip_to_bytes pfx_bytes "$addr"; then
echo "Invalid IP prefix: $pfx" >&2
return 1
fi
if (( ${#pfx_bytes[@]}*8 < cidr )); then
echo "Prefix CIDR too large" >&2
return 1
fi
# CIDR values might partially divide a byte so we need to mask out
# only the part of the byte we want to check for emptiness
if (( (pfx_bytes[cidr/8] & ~(~0 << (8-cidr%8))) != 0 )); then
echo "Invalid byte $((cidr/8)): $pfx" >&2
return 1
fi
local i
# Check the rest of the whole bytes to make sure they are empty
for (( i=cidr/8+1; i<${#pfx_bytes[@]}; i++ )); do
if (( pfx_bytes[$i] != 0 )); then
echo "Byte $i not 0: $pfx" >&2
return 1
fi
done
# Validate the suffix
local sfx_bytes=()
if ! ip_to_bytes sfx_bytes "$sfx"; then
echo "Invalid IPv6 suffix: $sfx" >&2
return 1
fi
if (( "${#sfx_bytes[@]}" != "${#pfx_bytes[@]}" )); then
echo "Suffix not the same family as prefix: $pfx $sfx" >&2
return 1
fi
# Check potential partially divided bytes for emptiness in the upper part
# based on the division specified in CIDR.
if (( (sfx_bytes[cidr/8] & (~0 << (8-cidr%8))) != 0 )); then
echo "Invalid byte $((cidr/8)): $sfx" >&2
return 1
fi
local i
# Check the bytes before the CIDR for emptiness to ensure they don't overlap
for (( i=0; i<cidr/8; i++ )); do
if (( sfx_bytes[$i] != 0 )); then
echo "Byte $i not 0: $sfx" >&2
return 1
fi
done
out_bytes=()
for (( i=0; i<${#pfx_bytes[@]}; i++ )); do
out_bytes+=($(( pfx_bytes[$i] | sfx_bytes[$i] )))
done
echo "$(ip_bytes_to_str out_bytes)/$cidr"
}
ip_pfx_to_cidr() {
[[ "$1" =~ ^[0-9a-fA-F:.]+/([0-9]+)$ ]] || return
echo "${BASH_REMATCH[1]}"
}
normalize_ip() {
local ip_bytes=()
ip_to_bytes ip_bytes "$1" || return
ip_bytes_to_str ip_bytes
}
network_init=1
return 0 2>/dev/null
echo "network is a library, not executed directly" >&2
exit 1
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