package/base-files/files/lib/functions/ipv4.sh

   1 uint_max=4294967295
   2
   3 # check that $1 is only base 10 digits, and that it doesn't
   4 # exceed 2^32-1
   5 assert_uint32() {
   6     local __n="$1"
   7
   8     if [ -z "$__n" -o -n "${__n//[0-9]/}" ]; then
   9         printf "Not a decimal integer (%s)\n" "$__n ">&2
  10         return 1
  11     fi
  12
  13     if [ "$__n" -gt $uint_max ]; then
  14         printf "Out of range (%s)\n" "$__n" >&2
  15         return 1
  16     fi
  17
  18     if [ "$((__n + 0))" != "$__n" ]; then
  19         printf "Not normalized notation (%s)\n" "$__n" >&2
  20         return 1
  21     fi
  22
  23     return 0
  24 }
  25
  26 # return a count of the number of bits set in $1
  27 bitcount() {
  28     local __var="$1" __c="$2"
  29     assert_uint32 "$__c" || return 1
  30
  31     __c=$((((__c >> 1) & 0x55555555) + (__c & 0x55555555)))
  32     __c=$((((__c >> 2) & 0x33333333) + (__c & 0x33333333)))
  33     __c=$((((__c >> 4) & 0x0f0f0f0f) + (__c & 0x0f0f0f0f)))
  34     __c=$((((__c >> 8) & 0x00ff00ff) + (__c & 0x00ff00ff)))
  35     __c=$((((__c >> 16) & 0x0000ffff) + (__c & 0x0000ffff)))
  36
  37     export -- "$__var=$__c"
  38 }
  39
  40 # tedious but portable with busybox's limited shell
  41 # we check each octet to be in the range of 0..255,
  42 # and also make sure there's no extaneous characters.
  43 str2ip() {
  44     local __var="$1" __ip="$2" __n __val=0
  45
  46     case "$__ip" in
  47     [0-9].*)
  48         __n="${__ip:0:1}"
  49         __ip="${__ip:2}"
  50         ;;
  51     [1-9][0-9].*)
  52         __n="${__ip:0:2}"
  53         __ip="${__ip:3}"
  54         ;;
  55     1[0-9][0-9].*|2[0-4][0-9].*|25[0-5].*)
  56         __n="${__ip:0:3}"
  57         __ip="${__ip:4}"
  58         ;;
  59     *)
  60         printf "Not a dotted quad (%s)\n" "$2" >&2
  61         return 1
  62         ;;
  63     esac
  64
  65     __val=$((__n << 24))
  66
  67     case "$__ip" in
  68     [0-9].*)
  69         __n="${__ip:0:1}"
  70         __ip="${__ip:2}"
  71         ;;
  72     [1-9][0-9].*)
  73         __n="${__ip:0:2}"
  74         __ip="${__ip:3}"
  75         ;;
  76     1[0-9][0-9].*|2[0-4][0-9].*|25[0-5].*)
  77         __n="${__ip:0:3}"
  78         __ip="${__ip:4}"
  79         ;;
  80     *)
  81         printf "Not a dotted quad (%s)\n" "$2" >&2
  82         return 1
  83         ;;
  84     esac
  85
  86     __val=$((__val + (__n << 16)))
  87
  88     case "$__ip" in
  89     [0-9].*)
  90         __n="${__ip:0:1}"
  91         __ip="${__ip:2}"
  92         ;;
  93     [1-9][0-9].*)
  94         __n="${__ip:0:2}"
  95         __ip="${__ip:3}"
  96         ;;
  97     1[0-9][0-9].*|2[0-4][0-9].*|25[0-5].*)
  98         __n="${__ip:0:3}"
  99         __ip="${__ip:4}"
 100         ;;
 101     *)
 102         printf "Not a dotted quad (%s)\n" "$2" >&2
 103         return 1
 104         ;;
 105     esac
 106
 107     __val=$((__val + (__n << 8)))
 108
 109     case "$__ip" in
 110     [0-9])
 111         __n="${__ip:0:1}"
 112         __ip="${__ip:1}"
 113         ;;
 114     [1-9][0-9])
 115         __n="${__ip:0:2}"
 116         __ip="${__ip:2}"
 117         ;;
 118     1[0-9][0-9]|2[0-4][0-9]|25[0-5])
 119         __n="${__ip:0:3}"
 120         __ip="${__ip:3}"
 121         ;;
 122     *)
 123         printf "Not a dotted quad (%s)\n" "$2" >&2
 124         return 1
 125         ;;
 126     esac
 127
 128     __val=$((__val + __n))
 129
 130     if [ -n "$__ip" ]; then
 131         printf "Not a dotted quad (%s)\n" "$2" >&2
 132         return 1
 133     fi
 134
 135     export -- "$__var=$__val"
 136     return 0
 137 }
 138
 139 # convert back from an integer to dotted-quad.
 140 ip2str() {
 141     local __var="$1" __n="$2"
 142     assert_uint32 "$__n" || return 1
 143
 144     export -- "$__var=$((__n >> 24)).$(((__n >> 16) & 255)).$(((__n >> 8) & 255)).$((__n & 255))"
 145 }
 146