#!/bin/bash
# quickGetPing - How to collect many ping's outputs into bash variables
# (C) 2025 Felix Hauri - felix@f-hauri.ch
# Licensed under terms of GPL v3. www.gnu.org
# This script is intented to be used under GNU/Linux, as they use kernel
#   pseudo filesystem /proc (only in `getArps` function).
# Collecting networks IPv4 status and infos from parallelized ping's answer,
#   into three differents bash arrays:
#  - $listHosts  Associative array: ([hosta]='10.2.3.45' [hostb]='10.2.3.46'...
#  - $byIp       Indexed array: ([167904045]='hosta' [167904046]='hostb'...
#  - $stateList  Integer idexed array: ([167904045]='1' [167904046]='0'...
# Note: In order to avoid bash loops, all array operation are done by "mapping"
#   ( While keeping in mind `declare -a "$str"` is like an `eval`!! )
# In a second operation, variable "$listArps" are built with command:
# mapfile </proc/net/arp to an indexed array: ([167904045]="01:23:45:67:89:ab"..
#
# Usage: quickGetPing <ip or hostname> [ip or hostname] [ip or hostname]...
#    Something like: quickGetPing $(awk '/^[1.9]/{if($3)print $3}' </etc/hosts)
# Tried with 1016 arguments (<2sec): quickGetPing 192.168.{0..3}.{1..254} 
# Warning: Both `int2ip` and `ip2int` routines will process array arguments
#   without any kind of verification! `checkIPv4` is not used at all (for now.)

: ${numPing:=1} ${showArrays:=false}

int2ip() { # Convert array of __tmp_integer to array of IPv4, by mapping 
    if [[ $1 == -v ]]; then
	local __out_var="$2"
	shift 2
    else
	local __out_var=
    fi
    local __tmp_str='%d.%%d.%%%%d.%%%%%%%%d\n' i
    local -ai __tmp_int=("${@/*/& >> 24       }")
    printf -v __tmp_str "$__tmp_str"  ${__tmp_int[@]}
    local -ai __tmp_int=("${@/*/& >> 16 \& 255}")
    printf -v __tmp_str "$__tmp_str"  ${__tmp_int[@]}
    local -ai __tmp_int=("${@/*/& >>  8 \& 255}")
    printf -v __tmp_str "$__tmp_str"  ${__tmp_int[@]}
    local -ai __tmp_int=("${@/*/&       \& 255}")
    printf -v __tmp_str "$__tmp_str"  ${__tmp_int[@]}
    if [[ $__out_var ]]; then
	mapfile -t "$__out_var" <<<"${__tmp_str%$'\n'}"
    else
	echo "${__tmp_str//$'\n'/ }"
    fi
}
ip2int() { # Convert array of IPv4 to array of integer, by mapping
    if [[ $1 == -v ]]; then
	local __out_var="$2"
	shift 2
    else
	local __out_var=
    fi
    set -- "${@/./<<24|}"; set -- "${@/./<<16|}"; set -- "${@/./<<8|}"
    local -ai res=("$@")    
    if [[ $__out_var ]]; then
	mapfile -d\  -t "$__out_var" <<<"${res[*]}"
    else
	echo "${res[*]}"
    fi
}
checkIPv4() { # Work in progress, not used in this script.
    local __args_array=("$@") __tmp_str
    printf -v __tmp_str '[%s]= ' ${__args_array[*]//[0-9]}
    local -A __check_Aarray="($__tmp_str)"
    (( ${#__check_Aarray[@]} == 1 )) && [[ ${!__check_Aarray[*]} == ... ]] ||
	return 1;
    __args_array=(${__args_array[*]//[12][0-9][0-9]/.})
    __args_array=(${__args_array[*]//[0-9][0-9]/.})
    printf -v __tmp_str '[%s]= ' ${__args_array[*]//[0-9]/.}
    local -A __check_Aarray="($__tmp_str)"
    (( ${#__check_Aarray[@]} == 1 ))&& [[ ${!__check_Aarray[*]} == ....... ]]||
	return 1
    printf -v __tmp_str ' %d > 255 || ' ${*//./ }
    return $(($__tmp_str 0))
}
runPPing () {
    # This will create 3 array variables by using SDTOUT and 2 more FDs in
    # backgrounded task (sed) who will send separatedly, required output
    # to specific FD.
    local -i hstFd byIpFd 
    local str
    exec {hstFd}<> <(:);
    exec {byIpFd}<> <(:);
    local -ai upList="($(
	sed -une '
	  /PING \(.*\) (\([0-9.]\+\)) 56.*/{
	    s//[\1]=\2 /;
	    w /dev/fd/'$hstFd -e '
	    /\[\(.*\)\]=\([0-9]\+\)\.\([0-9]\+\)\.\([0-9]\+\)\.\([0-9]\+\) $/{
	      s//[\2<<24|\3<<16|\4<<8|\5]="\1" /;w /dev/fd/'$byIpFd -e '
     	      };
	  };
	  /^64.*(\([0-9]\+\)\.\([0-9]\+\)\.\([0-9]\+\)\.\([0-9]\+\)):.*/{
	    s//[\1<<24|\2<<16|\3<<8|\4]=1 /p
	  };
	  /^64 .* from \([0-9]\+\)\.\([0-9]\+\)\.\([0-9]\+\)\.\([0-9]\+\)[^)]*/{
	    s//[\1<<24|\2<<16|\3<<8|\4]=1 /p
	  };
	' < <(
	    for hst; do # in ${hosts[@]}; do
		ping -c$numPing -W1 $hst &
	    done
	    wait
    )))"

    printf '\1' >&$hstFd
    read -d$'\1' -u $hstFd str
    exec {hstFd}>&-
    declare -gA "listHosts=(${str//$'\n'})"
    
    printf '\1' >&$byIpFd
    read -d$'\1' -u $byIpFd str
    exec {byIpFd}>&-
    declare -ga "byIp=(${str//$'\n'})"

    printf -v str '[%s]=0 ' ${!byIp[@]}
    declare -gai "stateList=($str)"
    printf -v str '[%d]+=1 ' ${!upList[@]}
    declare -gai "stateList+=($str)"
}
getArps() {
    local arpList arpCleanedList str ips
    mapfile -t arpList </proc/net/arp
    arpList=("${arpList[@]:1}")
    arpCleanedList=("${arpList[@]//*00:00:00:00:00:00*}")
    arpList=("${arpCleanedList[@]##*0x[0-9] }")
    arpList=(${arpList[@]% [*] *})
    ip2int -v ips ${arpCleanedList[@]/ *}
    printf -v str '[%d]="%%s" ' ${ips[@]}
    printf -v str "$str" "${arpList[@]}"
    declare -ga "listArps=($str)"
}

started=$EPOCHREALTIME

runPPing "$@"

getArps

### Built variables could be show by uncommenting next line.
# declare -p listHosts byIp stateList listArps
$showArrays && declare -p listHosts byIp stateList listArps

msgs=(Down Up)
allInts=(${!byIp[@]})
int2ip -v sortedIp ${allInts[@]}
colors=( "${stateList[@]/0/2}" )
declare -a states="(${stateList[*]/*/\${msgs[&]\}})"
declare -a macaddrs="(${allInts[*]/*/\"\$\{listArps[&]\}\"})"

str='\e[%%%%%%%%%%%%%%%%sm%-24s %%-17s%%%%%%%%-19s%%%%s\e[0m\n'
printf -v str "$str"	Name		"${byIp[@]}"
printf -v str "$str"	IP\ Address	"${sortedIp[@]}"
printf -v str "$str"	State		"${states[@]}"
printf -v str "$str"	'Mac Address'	"${macaddrs[@]}"
printf "$str"		4		"${colors[@]/1/0}"

# echo "Same, but using a loop:"
# printf '\e[4m%-24s %-17s%-19s%s\e[0m\n' Name IP\ Address State Arps
# colors=(2 0)
# for int in ${!byIp[@]}; do
#     printf '\e[%sm%-24s %-17s%-19s%s\e[0m\n' \
#          ${colors[stateList[int]]}  ${byIp[int]} \
# 	   ${listHosts[${byIp[int]}]} \
# 	   "${listArps[int]}"  ${msgs[stateList[int]]}
# done

ended=$EPOCHREALTIME
elap=00000$(( ${ended/.} - ${started/.} ))
printf 'Processed: %d hosts in  %.3f seconds.\n' \
       ${#byIp[@]}  ${elap::-6}.${elap: -6}