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

Also add better error checking on input.

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

1 files changed, 140 insertions, 0 deletions

diff --git a/package/base-files/files/lib/functions/ipv4.sh b/package/base-files/files/lib/functions/ipv4.sh
new file mode 100644
index 0000000000..30ae480305
--- /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))"
+}
+