network_tools/usr/local/lib/dns.bash

#!/bin/bash

if [[ "${DNS_BASH}" != "" ]]
then
    return
else
    declare -g DNS_BASH=1
fi



# Includes
#-----------------------------------------------------------------------------------------------------------------------------------

. /usr/global/lib/default.bash



#[ -e /var/cache/dns.cache ] && . /var/cache/dns.cache





# Global Variable
#-----------------------------------------------------------------------------------------------------------------------------------

declare -Ag DNS_A_TAB
declare -g  DNS_A_ID_LIST

declare -Ag DNS_PTR_TAB
declare -g  DNS_PTR_ID_LIST

declare -g  DNS_CACHE_FILE="/var/cache/dns.cache"
declare -g  DNS_CACHE_LOCK="/var/lock/network/dns.lock"
#declare -g  DNS_CACHE_LOCK="${DNS_CACHE_FILE}"

declare -g  DNS_CACHE_UPDATED=0


if [ ! -v LOG ] || [[ "${LOG}" == "" ]]
then
    export LOG=":"
fi





#--------------------------------------------------------------------------------------------------------------------------
# dns_tab_load
#--------------------------------------------------------------------------------------------------------------------------

dns_tab_load()
{
    ${LOG} 1>&2 "Loading DNS cache..."
    
    file_lock "${DNS_CACHE_LOCK}" READ 9
    
    if [[ ( -e "${DNS_CACHE_FILE}" ) && ( "${NETWORK_CONFIG_FILE}" -ot "${DNS_CACHE_FILE}" ) ]]
    then
	${LOG} 1>&2 "DNS: Read CacheFile"
	    
	while IFS= read -r line
	do
	    line=${line%%#*}
	    if [[ ! -z "$line" ]]
	    then
		set ${line}

		 dtl_type="$1"
		  dtl_key="$2"
		dtl_value="$3"

		dns_tab_put ${dtl_type} "${dtl_key}" "${dtl_value}"
	    fi
	done < ${DNS_CACHE_FILE}
    else
	${LOG} 1>&2 "DNS: Init CacheFile"
	    
	>${DNS_CACHE_FILE}
    fi

    file_unlock 9
    
    DNS_CACHE_UPDATED=0
}





#--------------------------------------------------------------------------------------------------------------------------
# dns_tab_save
#--------------------------------------------------------------------------------------------------------------------------

dns_tab_save()
{
    ${LOG} 1>&2 "Saving DNS cache..."
    
    if [[ "${DNS_CACHE_UPDATED}" != "0" ]]
    then
        file_lock "${DNS_CACHE_LOCK}" WRITE 9

	${LOG} 1>&2 "DNS: Write CacheFile"
	    
	(
	    for key in "${!DNS_A_TAB[@]}"
	    do
		echo "A ${key} ${DNS_A_TAB[${key}]}"
	    done
	    
	    for key in "${!DNS_PTR_TAB[@]}"
	    do
		echo "PTR ${key} ${DNS_PTR_TAB[${key}]}"
	    done
	) | sort -n >${DNS_CACHE_FILE}

        file_unlock 9

	DNS_CACHE_UPDATED=0
    fi
}





#--------------------------------------------------------------------------------------------------------------------------
# dns_tab_get
#--------------------------------------------------------------------------------------------------------------------------

dns_tab_get()
{
    dns_type="$1"
     dns_key="$2"

     
    case ${dns_type}
    in
	"A")
	    if [[ -v DNS_A_TAB["${dns_key}"] ]]
	    then
		dns_value="${DNS_A_TAB["${dns_key}"]}"
	    else
		${LOG} "DNS: Lookup failed: Type: [${dns_type}]   Key: [${dns_key}]"
		return 1
	    fi
	;;
	
	"PTR")
	    if [[ -v DNS_PTR_TAB["${dns_key}"] ]]
	    then
		dns_value="${DNS_PTR_TAB["${dns_key}"]}"
	    else
		${LOG} "DNS: Lookup failed: Type: [${dns_type}]   Key: [${dns_key}]"
		return 1
	    fi
	;;	
    esac

    ${LOG} "DNS: Lookup succeed: Type: [${dns_type}]   Key: [${dns_key}]   Value: [${dns_value}]"

    return 0
}





#--------------------------------------------------------------------------------------------------------------------------
# dns_tab_put
#--------------------------------------------------------------------------------------------------------------------------

dns_tab_put()
{
     dtp_type="$1"
      dtp_key="$2"
    dtp_value="$3"


    if [[ "${dtp_value}" == "" ]]
    then
	${LOG} 1>&2 "DNS: Skiping cache entry: Type: [${dtp_type}]   Key: [${dtp_key}]   Value: [${dtp_value}]"
    else
	${LOG} 1>&2 "DNS: Update cache entry: Type: [${dtp_type}]   Key: [${dtp_key}]   Value: [${dtp_value}]"
    
	var_assign DNS_${dtp_type}_ID_LIST "${dtp_key}" INC
	tab_assign DNS_${dtp_type}_TAB     "${dtp_key}" "${dtp_value}"

	DNS_CACHE_UPDATED=1
    fi
}





#--------------------------------------------------------------------------------------------------------------------------
# dns_lookup
#--------------------------------------------------------------------------------------------------------------------------

dns_lookup()
{
    dl_type="$1"
     dl_key="$2"
    dl_flag="$3"


    if [[ "${dl_flag}" != "NOCACHE" ]]
    then
	dns_tab_get ${dl_type} ${dl_key}
    else
	false
    fi

    if [[ "$?" != "0" ]]
    then
	${LOG} "DNS: Out of Cache: Type: [${dl_type}]   Key: [${dl_key}]   Flag: [${dl_flag}]"
	
	case ${dl_type}
	in
	    "A")
		dns_value="$( dig +short    ${dl_key} 2>/dev/null)"   
		;;
	    
	    "PTR")
		dns_value="$( dig +short -x ${dl_key} 2>/dev/null)"
                dns_value="${dns_value%.}"
		;;
	esac

	if [[ "${dl_flag}" != "NOCACHE" ]]
	then
	    dns_tab_put "${dl_type}" "${dl_key}" "${dns_value}"
	fi
    fi
}





#--------------------------------------------------------------------------------------------------------------------------
# dns_tab_dump
#--------------------------------------------------------------------------------------------------------------------------

dns_tab_dump()
{
    echo "DNS_A_ID_LIST: [${DNS_A_ID_LIST}]"
    echo

    echo "DNS_A_TAB:"

    for key in "${!DNS_A_TAB[@]}"
    do
        echo "[${key}]: [${DNS_A_TAB[${key}]}]"
    done | sort -n

    echo
    
    echo "DNS_PTR_ID_LIST: [${DNS_PTR_ID_LIST}]"
    echo
    
    echo "DNS_PTR_TAB:"

    for key in "${!DNS_PTR_TAB[@]}"
    do
        echo "[${key}]: [${DNS_PTR_TAB[${key}]}]"
    done | sort -n

    echo
}