base-files: ipcalc.sh: Rewrite in pure shell

Also add better error checking on input.

Signed-off-by: Philip Prindeville <philipp@redfish-solutions.com>

diff --git a/package/base-files/files/bin/ipcalc.sh b/package/base-files/files/bin/ipcalc.sh
index 9b5e5accdca8ca1c4198ae573240eb57e7e70448..0bd6edd07aa0946c84f4ee756e097aed506d0552 100755 (executable)
--- a/package/base-files/files/bin/ipcalc.sh
+++ b/package/base-files/files/bin/ipcalc.sh
@@ -1,100 +1,109 @@
-#!/usr/bin/awk -f
-
-function bitcount(c) {
-       c=and(rshift(c, 1),0x55555555)+and(c,0x55555555)
-       c=and(rshift(c, 2),0x33333333)+and(c,0x33333333)
-       c=and(rshift(c, 4),0x0f0f0f0f)+and(c,0x0f0f0f0f)
-       c=and(rshift(c, 8),0x00ff00ff)+and(c,0x00ff00ff)
-       c=and(rshift(c,16),0x0000ffff)+and(c,0x0000ffff)
-       return c
-}
+#!/bin/sh
 
-function ip2int(ip) {
-       ret=0
-       n=split(ip,a,"\\.")
-       for (x=1;x<=n;x++)
-               ret=or(lshift(ret,8),a[x])
-       return ret
-}
+. /lib/functions/ipv4.sh
 
-function int2ip(ip,ret,x) {
-       ret=and(ip,255)
-       ip=rshift(ip,8)
-       for(;x<3;x++) {
-               ret=and(ip,255)"."ret
-               ip=rshift(ip,8)
-       }
-       return ret
-}
+PROG="$(basename "$0")"
 
-function compl32(v) {
-       ret=xor(v, 0xffffffff)
-       return ret
+usage() {
+    echo "Usage: $PROG address/prefix [ start limit ]" >&2
+    exit 1
 }
 
-BEGIN {
-       slpos=index(ARGV[1],"/")
-       if (slpos != 0) {
-               # rearrange arguments to not use compound notation
-               ARGV[4]=ARGV[3]
-               ARGV[3]=ARGV[2]
-               ARGV[2]=substr(ARGV[1],slpos+1)
-               ARGV[1]=substr(ARGV[1],0,slpos-1)
-       }
-       ipaddr=ip2int(ARGV[1])
-       dotpos=index(ARGV[2],".")
-       if (dotpos == 0)
-               netmask=compl32(2**(32-int(ARGV[2]))-1)
-       else
-               netmask=ip2int(ARGV[2])
-
-       network=and(ipaddr,netmask)
-       prefix=32-bitcount(compl32(netmask))
-
-       print "IP="int2ip(ipaddr)
-       print "NETMASK="int2ip(netmask)
-       print "NETWORK="int2ip(network)
-       if (prefix<=30) {
-               broadcast=or(network,compl32(netmask))
-               print "BROADCAST="int2ip(broadcast)
-       }
-       print "PREFIX="prefix
-
-       # range calculations:
-       # ipcalc <ip> <netmask> <range_start> <range_size>
-
-       if (ARGC <= 3)
-               exit(0)
-
-       if (prefix<=30)
-               limit=network+1
-       else
-               limit=network
-
-       start=or(network,and(ip2int(ARGV[3]),compl32(netmask)))
-       if (start<limit) start=limit
-       if (start==ipaddr) start=ipaddr+1
-
-       if (prefix<=30)
-               limit=or(network,compl32(netmask))-1
-       else
-               limit=or(network,compl32(netmask))
-
-       end=start+ARGV[4]-1
-       if (end>limit) end=limit
-       if (end==ipaddr) end=ipaddr-1
-
-       if (start>end) {
-               print "network ("int2ip(network)"/"prefix") too small" > "/dev/stderr"
-               exit(1)
-       }
-
-       if (ipaddr >= start && ipaddr <= end) {
-               print "warning: ipaddr inside range - this might not be supported in future releases of Openwrt" > "/dev/stderr"
-               # turn this into an error after Openwrt 24 has been released
-               # exit(1)
-       }
-
-       print "START="int2ip(start)
-       print "END="int2ip(end)
-}
+if [ $# -eq 0 ]; then
+    usage
+fi
+
+case "$1" in
+*/*.*)
+    str2ip ipaddr "${1%/*}" || exit 1
+    str2ip netmask "${1#*/}" || exit 1
+    shift
+    ;;
+*/*)
+    str2ip ipaddr "${1%/*}" || exit 1
+    prefix="${1#*/}"
+    assert_uint32 "$prefix" || exit 1
+    if [ "$prefix" -gt 32 ]; then
+       printf "Prefix out of range (%s)\n" "$prefix" >&2
+       exit 1
+    fi
+    netmask=$(((0xffffffff << (32 - prefix)) & 0xffffffff))
+    shift
+    ;;
+*)
+    str2ip ipaddr "$1" || exit 1
+    str2ip netmask "$2" || exit 1
+    shift 2
+    ;;
+esac
+
+if [ $# -ne 0 ] && [ $# -ne 2 ]; then
+    usage
+fi
+
+if ! bitcount prefix "$netmask"; then
+    printf "Invalid netmask (%s)\n" "$netmask" >&2
+    exit 1
+fi
+
+# complement of the netmask, i.e. the hostmask
+hostmask=$((netmask ^ 0xffffffff))
+network=$((ipaddr & netmask))
+broadcast=$((network | hostmask))
+
+ip2str IP "$ipaddr"
+ip2str NETMASK "$netmask"
+ip2str NETWORK "$network"
+
+echo "IP=$IP"
+echo "NETMASK=$NETMASK"
+if [ "$prefix" -le 30 ]; then
+    ip2str BROADCAST "$broadcast"
+    echo "BROADCAST=$BROADCAST"
+fi
+echo "NETWORK=$NETWORK"
+echo "PREFIX=$prefix"
+
+[ $# -eq 0 ] && exit 0
+
+if [ "$prefix" -le 30 ]; then
+    lower=$((network + 1))
+else
+    lower="$network"
+fi
+
+start="$1"
+assert_uint32 "$start" || exit 1
+start=$((network | (start & hostmask)))
+[ "$start" -lt "$lower" ] && start="$lower"
+[ "$start" -eq "$ipaddr" ] && start=$((start + 1))
+
+if [ "$prefix" -le 30 ]; then
+    upper=$(((network | hostmask) - 1))
+else
+    upper="$network"
+fi
+
+range="$2"
+assert_uint32 "$range" || exit 1
+end=$((start + range - 1))
+[ "$end" -gt "$upper" ] && end="$upper"
+[ "$end" -eq "$ipaddr" ] && end=$((end - 1))
+
+if [ "$start" -gt "$end" ]; then
+    echo "network ($NETWORK/$prefix) too small" >&2
+    exit 1
+fi
+
+ip2str START "$start"
+ip2str END "$end"
+
+if [ "$start" -le "$ipaddr" ] && [ "$ipaddr" -le "$end" ]; then
+    echo "error: address $IP inside range $START..$END" >&2
+    exit 1
+fi
+
+echo "START=$START"
+echo "END=$END"
+
+exit 0

diff --git a/package/base-files/files/lib/functions/ipv4.sh b/package/base-files/files/lib/functions/ipv4.sh
new file mode 100644 (file)
index 0000000..30ae480
--- /dev/null
+++ b/package/base-files/files/lib/functions/ipv4.sh
@@ -0,0 +1,140 @@
+uint_max=4294967295
+
+assert_uint32() {
+    local __n="$1"
+
+    if [ -z "$__n" -o -n "${__n//[0-9]/}" ]; then
+       printf "Not a decimal integer (%s)\n" "$__n ">&2
+       return 1
+    fi
+
+    if [ "$__n" -gt $uint_max ]; then
+       printf "Out of range (%s)\n" "$__n" >&2
+       return 1
+    fi
+
+    if [ "$((__n + 0))" != "$__n" ]; then
+       printf "Not normalized notation (%s)\n" "$__n" >&2
+       return 1
+    fi
+
+    return 0
+}
+
+bitcount() {
+    local __var="$1" __c="$2"
+    assert_uint32 "$__c" || return 1
+
+    __c=$((((__c >> 1) & 0x55555555) + (__c & 0x55555555)))
+    __c=$((((__c >> 2) & 0x33333333) + (__c & 0x33333333)))
+    __c=$((((__c >> 4) & 0x0f0f0f0f) + (__c & 0x0f0f0f0f)))
+    __c=$((((__c >> 8) & 0x00ff00ff) + (__c & 0x00ff00ff)))
+    __c=$((((__c >> 16) & 0x0000ffff) + (__c & 0x0000ffff)))
+
+    export -- "$__var=$__c"
+}
+
+# tedious but portable with busybox's limited shell
+str2ip() {
+    local __var="$1" __ip="$2" __n __val=0
+
+    case "$__ip" in
+    [0-9].*)
+       __n="${__ip:0:1}"
+       __ip="${__ip:2}"
+       ;;
+    [1-9][0-9].*)
+       __n="${__ip:0:2}"
+       __ip="${__ip:3}"
+       ;;
+    1[0-9][0-9].*|2[0-4][0-9].*|25[0-5].*)
+       __n="${__ip:0:3}"
+       __ip="${__ip:4}"
+       ;;
+    *)
+       printf "Not a dotted quad (%s)\n" "$2" >&2
+       return 1
+       ;;
+    esac
+
+    __val=$((__n << 24))
+
+    case "$__ip" in
+    [0-9].*)
+       __n="${__ip:0:1}"
+       __ip="${__ip:2}"
+       ;;
+    [1-9][0-9].*)
+       __n="${__ip:0:2}"
+       __ip="${__ip:3}"
+       ;;
+    1[0-9][0-9].*|2[0-4][0-9].*|25[0-5].*)
+       __n="${__ip:0:3}"
+       __ip="${__ip:4}"
+       ;;
+    *)
+       printf "Not a dotted quad (%s)\n" "$2" >&2
+       return 1
+       ;;
+    esac
+
+    __val=$((__val + (__n << 16)))
+
+    case "$__ip" in
+    [0-9].*)
+       __n="${__ip:0:1}"
+       __ip="${__ip:2}"
+       ;;
+    [1-9][0-9].*)
+       __n="${__ip:0:2}"
+       __ip="${__ip:3}"
+       ;;
+    1[0-9][0-9].*|2[0-4][0-9].*|25[0-5].*)
+       __n="${__ip:0:3}"
+       __ip="${__ip:4}"
+       ;;
+    *)
+       printf "Not a dotted quad (%s)\n" "$2" >&2
+       return 1
+       ;;
+    esac
+
+    __val=$((__val + (__n << 8)))
+
+    case "$__ip" in
+    [0-9])
+       __n="${__ip:0:1}"
+       __ip="${__ip:1}"
+       ;;
+    [1-9][0-9])
+       __n="${__ip:0:2}"
+       __ip="${__ip:2}"
+       ;;
+    1[0-9][0-9]|2[0-4][0-9]|25[0-5])
+       __n="${__ip:0:3}"
+       __ip="${__ip:3}"
+       ;;
+    *)
+       printf "Not a dotted quad (%s)\n" "$2" >&2
+       return 1
+       ;;
+    esac
+
+    __val=$((__val + __n))
+
+    if [ -n "$__ip" ]; then
+       printf "Not a dotted quad (%s)\n" "$2" >&2
+       return 1
+    fi
+
+    export -- "$__var=$__val"
+    return 0
+}
+
+ip2str() {
+    local __var="$1" __n="$2"
+    assert_uint32 "$__n" || return 1
+
+    export -- "$__var=$((__n >> 24)).$(((__n >> 16) & 255)).$(((__n >> 8) & 255)).$((__n & 255))"
+}
+