#!/bin/bash
#.Y / 70 83 / / / / 105 / / / /	 / /	      ;A4_QUER.Y
#.YT 3 2 0 0 3 3 1 / / /
#.H!a!0:linux/<scripts>/io/com/net/dhcp/THIS!0.!c
#
# tbrü 20sep2011;
#
# dhcp_ THIS : dhcp-functions
# +++++++++++++++++++++++++++
#
# MyHash("linux/<scripts>/io/com/net/dhcp/THIS") = 0x0D01
#
# * for every function:
#   * if returned result is not commented, the function returns 0 on no-error.

SCRIPTS=root/bin

. /$SCRIPTS/io/con_/THIS

dhcp_qHost()                                       # ?Host
  # $1       : host-name.
  # $2, $3...: <mac-address-ip#-pairs>.
  # * write eventually "<host-name>"-file.
  # * return "0" if file is written; else return "1".
  {
    local  File0x0D01 HostName0x0D01

    HostName0x0D01="$1"; shift 1

    File0x0D01="/etc/dhcp/hosts.d/${HostName0x0D01}"
    if [ -f "$File0x0D01" ]; then
        echo "The File \"$File0x0D01\" already exists, do you want to"
        echo "overwrite it?"
        if ! con_YesQ; then
            return 1                               # do not write to file.
          fi
          # else
      fi
      # else
        dhcp_host "$HostName0x0D01" $@  > "$File0x0D01"
        return 0
  }


dhcp_qHostBAT()                                    # ?HostBAT
  # $1       : host-name.
  # $2, $3...: <mac-address-ip#-pairs>.
  # * write eventually "<host-name>.BAT".
  {
    local  File0x0D01 HostName0x0D01

    HostName0x0D01="$1"; shift 1

    File0x0D01="/etc/dhcp/hosts.d/${HostName0x0D01}.BAT"
    if [ -f "$File0x0D01" ]; then
        echo "The File \"$File0x0D01\" already exists, do you want to"
        echo "overwrite it?"
        if ! con_YesQ; then
            return 0                               # do not write to file.
          fi
          # else
      fi
      # else
        echo "DHCP_ HOST $HostName0x0D01  $@" > "$File0x0D01"
        return 0
  }


dhcp_adjustTHIS()
  # $1 : host-name.
  # * add "<host-name>"-declaration to dhcp-configuration.
  {
    local  THIS_File0x0D01

    THIS_File0x0D01="/etc/dhcp/hosts.d/THIS"

    # create temporary this-file:
      TempTHIS_File0x0D01="$(mktemp /etc/dhcp/hosts.d/THIS.tmp.XXXXXX)"

    echo "include  \"/etc/dhcp/hosts.d/$1\";" >> "$THIS_File0x0D01"
    sort -o "$TempTHIS_File0x0D01" "$THIS_File0x0D01"
    # delete duplicate lines:
      uniq  "$TempTHIS_File0x0D01" "$THIS_File0x0D01"
    rm -f  "$TempTHIS_File0x0D01"
    return 0
  }


dhcp_HOST()
  # $1       : host-name.
  # $2, $3...: <mac-address-ip#-pairs>.
  # * add "<host-name>"-declaration to dhcp-configuration.
  # * see "dhcp_hostUsage()".
  {
    local  HostName0x0D01

    HostName0x0D01="$1"; shift 1
    if [  0 -eq $#  -o  0 -ne $(( $# % 2 ))  ]; then
        # 0 or not an even # of remaining arguments.
          dhcp_hostUsage
          return 255
      fi
      # else

    dhcp_qHostBAT    "$HostName0x0D01" $@
    if ! dhcp_qHost  "$HostName0x0D01" $@; then
        # file has not been written.
          return 0
      fi
      # else

    dhcp_adjustTHIS  "$HostName0x0D01"
    service dhcpd restart
    return 0
  }


dhcp_host()
  # $1       : host-name.
  # $2, $3...: <mac-address-ip#-pairs>.
  # * print host-group-statement to stdout.
  {
    local     HostName0x0D01 I0x0D01

    HostName0x0D01="$1"; shift 1

    echo "group"                                   # for host-name
    echo "  {"                                     #   = "<HostName>".
    echo "    option host-name  \"$HostName0x0D01\";" # this name is set as
                                                   # hostname."
    echo "    option domain-name-servers  169.254.1.254;"

    I0x0D01=0
    while [ 0 -ne $# ]
      do
        dhcp_host1Entry  "$HostName0x0D01" $I0x0D01 "$1" "$2"
        shift 2
        (( I0x0D01++ ))
     done

    echo "  }"                                     # /group
    return 0
  }


dhcp_host1Entry()
  # $1: host-name.
  # $2: host-index.
  # $3: <mac-address>.
  # $4: <ip#>.
  # * print host-entry to stdout.
  {
    echo
    echo "    host ${1}_${2}"                      # host-identifier; used to
    echo "      {"                                 #   discern different host-
                                                   #   entries.
    echo "         hardware ethernet  $3;"         # mandatory statement,
                                                   #   "<HostName>" is not
                                                   #   found by name !!!"
    echo "         fixed-address      $4;"
    echo "      }"
    return 0
  }


dhcp_hostUsage()
  {
    echo "Usage: DHCP_ HOST <host-name> <mac-address-ip#-pairs>"
    echo "* \"<mac-address-ip#-pairs> := <mac-address-ip#-pair>"
    echo "                                        | <mac-address-ip#-pairs>;\""
    echo "* \"<mac-address-ip#-pair>  := <mac-address> <ip#>;\""
    echo
    echo "* add \"<host-name>\"-declaration to dhcp-configuration."
    return 0
  }