diff --git a/package/owipcalc/Makefile b/package/owipcalc/Makefile
new file mode 100644
index 0000000000..9ff9b24c2c
--- /dev/null
+++ b/package/owipcalc/Makefile
@@ -0,0 +1,49 @@
+#
+# Copyright (C) 2012 Jo-Philipp Wich <jow@openwrt.org>
+#
+# This is free software, licensed under the Apache 2 license.
+#
+
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=owipcalc
+PKG_RELEASE:=1
+
+include $(INCLUDE_DIR)/package.mk
+
+
+define Package/owipcalc
+  SECTION:=utils
+  CATEGORY:=Utilities
+  TITLE:=Simple IPv4/IPv6 address calculator
+  MAINTAINER:=Jo-Philipp Wich <jow@openwrt.org>
+endef
+
+define Package/owipcalc/description
+  The owipcalc utility supports a number of calculations and tests to work
+  with ip-address ranges, this is useful for scripts that e.g. need to
+  partition ipv6-prefixes into small subnets or to calculate address ranges
+  for dhcp pools.
+endef
+
+
+define Build/Prepare
+	$(INSTALL_DIR) $(PKG_BUILD_DIR)
+	$(CP) ./src/* $(PKG_BUILD_DIR)/
+endef
+
+define Build/Configure
+endef
+
+define Build/Compile
+	$(TARGET_CC) $(TARGET_CFLAGS) \
+		-o $(PKG_BUILD_DIR)/owipcalc $(PKG_BUILD_DIR)/owipcalc.c
+endef
+
+
+define Package/owipcalc/install
+	$(INSTALL_DIR) $(1)/usr/bin
+	$(INSTALL_BIN) $(PKG_BUILD_DIR)/owipcalc $(1)/usr/bin/owipcalc
+endef
+
+$(eval $(call BuildPackage,owipcalc))
diff --git a/package/owipcalc/src/owipcalc b/package/owipcalc/src/owipcalc
new file mode 100755
index 0000000000..650d9f0363
Binary files /dev/null and b/package/owipcalc/src/owipcalc differ
diff --git a/package/owipcalc/src/owipcalc.c b/package/owipcalc/src/owipcalc.c
new file mode 100644
index 0000000000..6d7a8aaf43
--- /dev/null
+++ b/package/owipcalc/src/owipcalc.c
@@ -0,0 +1,754 @@
+/*
+ * owipcalc - OpenWrt IP Calculator
+ *
+ *   Copyright (C) 2012 Jo-Philipp Wich <jow@openwrt.org>
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdlib.h>
+
+#include <string.h>
+#include <unistd.h>
+
+#include <arpa/inet.h>
+
+
+struct cidr {
+	uint8_t family;
+	uint32_t prefix;
+	union {
+		struct in_addr v4;
+		struct in6_addr v6;
+	} addr;
+	union {
+		char v4[sizeof("255.255.255.255/255.255.255.255 ")];
+		char v6[sizeof("FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF/128 ")];
+	} buf;
+};
+
+struct op {
+	const char *name;
+	const char *desc;
+	struct {
+		bool (*a1)(struct cidr *a);
+		bool (*a2)(struct cidr *a, struct cidr *b);
+	} f4;
+	struct {
+		bool (*a1)(struct cidr *a);
+		bool (*a2)(struct cidr *a, struct cidr *b);
+	} f6;
+};
+
+
+static bool quiet = false;
+static bool printed = false;
+
+
+static struct cidr * cidr_parse4(const char *s)
+{
+	char *p = NULL, *r;
+	struct in_addr mask;
+	struct cidr *addr = malloc(sizeof(struct cidr));
+
+	if (!addr || (strlen(s) >= sizeof(addr->buf.v4)))
+		goto err;
+
+	snprintf(addr->buf.v4, sizeof(addr->buf.v4), "%s", s);
+
+	addr->family = AF_INET;
+
+	if ((p = strchr(addr->buf.v4, '/')) != NULL)
+	{
+		*p++ = 0;
+
+		if (strchr(p, '.') != NULL)
+		{
+			if (inet_pton(AF_INET, p, &mask) != 1)
+				goto err;
+
+			for (addr->prefix = 0; mask.s_addr; mask.s_addr >>= 1)
+				addr->prefix += (mask.s_addr & 1);
+		}
+		else
+		{
+			addr->prefix = strtoul(p, &r, 10);
+
+			if ((p == r) || (*r != 0) || (addr->prefix > 32))
+				goto err;
+		}
+	}
+	else
+	{
+		addr->prefix = 32;
+	}
+
+	if (p == addr->buf.v4+1)
+		memset(&addr->addr.v4, 0, sizeof(addr->addr.v4));
+	else if (inet_pton(AF_INET, addr->buf.v4, &addr->addr.v4) != 1)
+		goto err;
+
+	return addr;
+
+err:
+	if (addr)
+		free(addr);
+
+	return NULL;
+}
+
+static bool cidr_add4(struct cidr *a, struct cidr *b)
+{
+	uint32_t x = ntohl(a->addr.v4.s_addr);
+	uint32_t y = ntohl(b->addr.v4.s_addr);
+
+	if ((a->family != AF_INET) || (b->family != AF_INET))
+		return false;
+
+	if ((uint32_t)(x + y) < x)
+	{
+		fprintf(stderr, "overflow during 'add'\n");
+		return false;
+	}
+
+	a->addr.v4.s_addr = htonl(x + y);
+	return true;
+}
+
+static bool cidr_sub4(struct cidr *a, struct cidr *b)
+{
+	uint32_t x = ntohl(a->addr.v4.s_addr);
+	uint32_t y = ntohl(b->addr.v4.s_addr);
+
+	if ((a->family != AF_INET) || (b->family != AF_INET))
+		return false;
+
+	if ((uint32_t)(x - y) > x)
+	{
+		fprintf(stderr, "underflow during 'sub'\n");
+		return false;
+	}
+
+	a->addr.v4.s_addr = htonl(x - y);
+	return true;
+}
+
+static bool cidr_network4(struct cidr *a)
+{
+	a->addr.v4.s_addr &= htonl(~((1 << (32 - a->prefix)) - 1));
+	a->prefix = 32;
+	return true;
+}
+
+static bool cidr_broadcast4(struct cidr *a)
+{
+	a->addr.v4.s_addr |= htonl(((1 << (32 - a->prefix)) - 1));
+	a->prefix = 32;
+	return true;
+}
+
+static bool cidr_contains4(struct cidr *a, struct cidr *b)
+{
+	uint32_t net1 = a->addr.v4.s_addr & htonl(~((1 << (32 - a->prefix)) - 1));
+	uint32_t net2 = b->addr.v4.s_addr & htonl(~((1 << (32 - a->prefix)) - 1));
+
+	printed = true;
+
+	if ((b->prefix >= a->prefix) && (net1 == net2))
+	{
+		if (!quiet) printf("1\n");
+		return true;
+	}
+	else
+	{
+		if (!quiet) printf("0\n");
+		return false;
+	}
+}
+
+static bool cidr_netmask4(struct cidr *a)
+{
+	struct in_addr mask;
+	char buf[sizeof("255.255.255.255 ")];
+
+	mask.s_addr = htonl(~((1 << (32 - a->prefix)) - 1));
+
+	if (!quiet)
+		printf("%s\n", inet_ntop(AF_INET, &mask, buf, sizeof(buf)));
+
+	printed = true;
+
+	return true;
+}
+
+static bool cidr_private4(struct cidr *a)
+{
+	uint32_t x = ntohl(a->addr.v4.s_addr);
+
+	printed = true;
+
+	if (((x >= 0x0A000000) && (x <= 0x0AFFFFFF)) ||
+	    ((x >= 0xAC100000) && (x <= 0xAC1FFFFF)) ||
+	    ((x >= 0xC0A80000) && (x <= 0xC0A8FFFF)))
+	{
+		if (!quiet) printf("1\n");
+		return true;
+	}
+	else
+	{
+		if (!quiet) printf("0\n");
+		return false;
+	}
+}
+
+static bool cidr_linklocal4(struct cidr *a)
+{
+	uint32_t x = ntohl(a->addr.v4.s_addr);
+
+	printed = true;
+
+	if ((x >= 0xA9FE0000) && (x <= 0xA9FEFFFF))
+	{
+		if (!quiet) printf("1\n");
+		return true;
+	}
+	else
+	{
+		if (!quiet) printf("0\n");
+		return false;
+	}
+}
+
+static bool cidr_print4(struct cidr *a)
+{
+	char *p;
+
+	if (a->family != AF_INET)
+		return false;
+
+	if (!(p = (char *)inet_ntop(AF_INET, &a->addr.v4, a->buf.v4, sizeof(a->buf.v4))))
+		return false;
+
+	if (!quiet)
+		printf("%s", p);
+
+	if (!quiet && (a->prefix < 32))
+		printf("/%u", a->prefix);
+
+	if (!quiet)
+		printf("\n");
+
+	printed = true;
+
+	return true;
+}
+
+
+static struct cidr * cidr_parse6(const char *s)
+{
+	char *p = NULL, *r;
+	struct cidr *addr = malloc(sizeof(struct cidr));
+
+	if (!addr || (strlen(s) >= sizeof(addr->buf.v6)))
+		goto err;
+
+	snprintf(addr->buf.v6, sizeof(addr->buf.v6), "%s", s);
+
+	addr->family = AF_INET6;
+
+	if ((p = strchr(addr->buf.v6, '/')) != NULL)
+	{
+		*p++ = 0;
+
+		addr->prefix = strtoul(p, &r, 10);
+
+		if ((p == r) || (*r != 0) || (addr->prefix > 128))
+			goto err;
+	}
+	else
+	{
+		addr->prefix = 128;
+	}
+
+	if (p == addr->buf.v6+1)
+		memset(&addr->addr.v6, 0, sizeof(addr->addr.v6));
+	else if (inet_pton(AF_INET6, addr->buf.v6, &addr->addr.v6) != 1)
+		goto err;
+
+	return addr;
+
+err:
+	if (addr)
+		free(addr);
+
+	return NULL;
+}
+
+static bool cidr_add6(struct cidr *a, struct cidr *b)
+{
+	uint8_t idx = 15, carry = 0, overflow = 0;
+
+	struct in6_addr *x = &a->addr.v6;
+	struct in6_addr *y = &b->addr.v6;
+
+	if ((a->family != AF_INET6) || (b->family != AF_INET6))
+		return false;
+
+	do {
+		overflow = !!((x->s6_addr[idx] + y->s6_addr[idx] + carry) >= 256);
+		x->s6_addr[idx] += y->s6_addr[idx] + carry;
+		carry = overflow;
+	}
+	while (idx-- > 0);
+
+	if (carry)
+	{
+		fprintf(stderr, "overflow during 'add'\n");
+		return false;
+	}
+
+	return true;
+}
+
+static bool cidr_sub6(struct cidr *a, struct cidr *b)
+{
+	uint8_t idx = 15, carry = 0, underflow = 0;
+
+	struct in6_addr *x = &a->addr.v6;
+	struct in6_addr *y = &b->addr.v6;
+
+	if ((a->family != AF_INET6) || (b->family != AF_INET6))
+		return false;
+
+	do {
+		underflow = !!((x->s6_addr[idx] - y->s6_addr[idx] - carry) < 0);
+		x->s6_addr[idx] -= y->s6_addr[idx] + carry;
+		carry = underflow;
+	}
+	while (idx-- > 0);
+
+	if (carry)
+	{
+		fprintf(stderr, "underflow during 'sub'\n");
+		return false;
+	}
+
+	return true;
+}
+
+static bool cidr_network6(struct cidr *a)
+{
+	uint8_t i;
+
+	for (i = 0; i < (128 - a->prefix) / 8; i++)
+		a->addr.v6.s6_addr[15-i] = 0;
+
+	if ((128 - a->prefix) % 8)
+		a->addr.v6.s6_addr[15-i] &= ~((1 << ((128 - a->prefix) % 8)) - 1);
+
+	return true;
+}
+
+static bool cidr_contains6(struct cidr *a, struct cidr *b)
+{
+	struct in6_addr *x = &a->addr.v6;
+	struct in6_addr *y = &b->addr.v6;
+
+	uint8_t i = (128 - a->prefix) / 8;
+	uint8_t m = ~((1 << ((128 - a->prefix) % 8)) - 1);
+	uint8_t net1 = x->s6_addr[15-i] & m;
+	uint8_t net2 = y->s6_addr[15-i] & m;
+
+	printed = true;
+
+	if ((b->prefix >= a->prefix) && (net1 == net2) &&
+	    ((i == 15) || !memcmp(&x->s6_addr, &y->s6_addr, 15-i)))
+	{
+		if (!quiet) printf("1\n");
+		return true;
+	}
+	else
+	{
+		if (!quiet) printf("0\n");
+		return false;
+	}
+}
+
+static bool cidr_linklocal6(struct cidr *a)
+{
+	printed = true;
+
+	if ((a->addr.v6.s6_addr[0] == 0xFE) &&
+	    (a->addr.v6.s6_addr[1] >= 0x80) &&
+	    (a->addr.v6.s6_addr[1] <= 0xBF))
+	{
+		if (!quiet) printf("1\n");
+		return true;
+	}
+	else
+	{
+		if (!quiet) printf("0\n");
+		return false;
+	}
+}
+
+static bool cidr_ula6(struct cidr *a)
+{
+	printed = true;
+
+	if ((a->addr.v6.s6_addr[0] >= 0xFC) &&
+	    (a->addr.v6.s6_addr[0] <= 0xFD))
+	{
+		if (!quiet) printf("1\n");
+		return true;
+	}
+	else
+	{
+		if (!quiet) printf("0\n");
+		return false;
+	}
+}
+
+static bool cidr_print6(struct cidr *a)
+{
+	char *p;
+
+	if (a->family != AF_INET6)
+		return NULL;
+
+	if (!(p = (char *)inet_ntop(AF_INET6, &a->addr.v6, a->buf.v6, sizeof(a->buf.v6))))
+		return false;
+
+	if (!quiet)
+		printf("%s", p);
+
+	if (!quiet && (a->prefix < 128))
+		printf("/%u", a->prefix);
+
+	if (!quiet)
+		printf("\n");
+
+	printed = true;
+
+	return true;
+}
+
+
+static struct cidr * cidr_parse(const char *op, const char *s, int af_hint)
+{
+	char *r;
+	struct cidr *a;
+
+	uint8_t i;
+	uint32_t sum = strtoul(s, &r, 0);
+
+	if ((r > s) && (*r == 0))
+	{
+		a = malloc(sizeof(struct cidr));
+
+		if (!a)
+			return NULL;
+
+		if (af_hint == AF_INET)
+		{
+			a->family = AF_INET;
+			a->prefix = 32;
+			a->addr.v4.s_addr = htonl(sum);
+		}
+		else
+		{
+			a->family = AF_INET6;
+			a->prefix = 128;
+
+			for (i = 0; i <= 15; i++)
+			{
+				a->addr.v6.s6_addr[15-i] = sum % 256;
+				sum >>= 8;
+			}
+		}
+
+		return a;
+	}
+
+	if (strchr(s, ':'))
+		a = cidr_parse6(s);
+	else
+		a = cidr_parse4(s);
+
+	if (!a)
+		return NULL;
+
+	if (a->family != af_hint)
+	{
+		fprintf(stderr, "attempt to '%s' %s with %s address\n",
+				op,
+				(af_hint == AF_INET) ? "ipv4" : "ipv6",
+				(af_hint != AF_INET) ? "ipv4" : "ipv6");
+		exit(4);
+	}
+
+	return a;
+}
+
+static bool cidr_howmany(struct cidr *a, struct cidr *b)
+{
+	if (!quiet)
+	{
+		if (b->prefix < a->prefix)
+			printf("0\n");
+		else
+			printf("%u\n", 1 << (b->prefix - a->prefix));
+	}
+
+	printed = true;
+
+	return true;
+}
+
+static bool cidr_quiet(struct cidr *a)
+{
+	quiet = true;
+	return true;
+}
+
+
+struct op ops[] = {
+	{ .name = "add",
+	  .desc = "Add argument to base address",
+	  .f4.a2 = cidr_add4,
+	  .f6.a2 = cidr_add6 },
+
+	{ .name = "sub",
+	  .desc = "Substract argument from base address",
+	  .f4.a2 = cidr_sub4,
+	  .f6.a2 = cidr_sub6 },
+
+	{ .name = "network",
+	  .desc = "Turn base address into network address",
+	  .f4.a1 = cidr_network4,
+	  .f6.a1 = cidr_network6 },
+
+	{ .name = "broadcast",
+	  .desc = "Turn base address into broadcast address",
+	  .f4.a1 = cidr_broadcast4 },
+
+	{ .name = "netmask",
+	  .desc = "Print netmask of base address, does not change base address",
+	  .f4.a1 = cidr_netmask4 },
+
+	{ .name = "howmany",
+	  .desc = "Print amount of righ-hand prefixes that fit into base address, "
+	          "does not change base address",
+	  .f4.a2 = cidr_howmany,
+	  .f6.a2 = cidr_howmany },
+
+	{ .name = "contains",
+	  .desc = "Print '1' if argument fits into base address or '0' "
+	          "if not, does not change base address",
+	  .f4.a2 = cidr_contains4,
+	  .f6.a2 = cidr_contains6 },
+
+	{ .name = "private",
+	  .desc = "Print '1' if base address is in RFC1918 private space or '0' "
+	          "if not, does not change base address",
+	  .f4.a1 = cidr_private4 },
+
+	{ .name = "linklocal",
+	  .desc = "Print '1' if base address is in 169.254.0.0/16 or FE80::/10 "
+	          "link local space or '0' if not, does not change base address",
+	  .f4.a1 = cidr_linklocal4,
+	  .f6.a1 = cidr_linklocal6 },
+
+	{ .name = "ula",
+	  .desc = "Print '1' if base address is in FC00::/7 unique local address "
+	          "(ULA) space or '0' if not, does not change base address",
+	  .f6.a1 = cidr_ula6 },
+
+	{ .name = "quiet",
+	  .desc = "Suppress output, useful for test operation where the result can "
+	          "be inferred from the exit code, does not change base address",
+	  .f4.a1 = cidr_quiet,
+	  .f6.a1 = cidr_quiet },
+
+	{ .name = "print",
+	  .desc = "Print intermediate result, invoked implicitely at the end of "
+	          "calculation if no intermediate prints happened",
+	  .f4.a1 = cidr_print4,
+	  .f6.a1 = cidr_print6 },
+};
+
+static void usage(const char *prog)
+{
+	int i;
+
+	fprintf(stderr,
+	        "\n"
+	        "Usage:\n\n"
+	        "  %s {base address} operation [argument] "
+	        "[operation [argument] ...]\n\n"
+	        "Operations:\n\n",
+	        prog);
+
+	for (i = 0; i < sizeof(ops) / sizeof(ops[0]); i++)
+	{
+		if (ops[i].f4.a2 || ops[i].f6.a2)
+		{
+			fprintf(stderr, "  %s %s\n",
+			        ops[i].name,
+			        (ops[i].f4.a2 && ops[i].f6.a2) ? "{ipv4/ipv6/amount}" :
+			         (ops[i].f6.a2 ? "{ipv6/amount}" : "{ipv4/amount}"));
+		}
+		else
+		{
+			fprintf(stderr, "  %s\n", ops[i].name);
+		}
+
+		fprintf(stderr, "    %s.\n", ops[i].desc);
+
+		if ((ops[i].f4.a1 && ops[i].f6.a1) || (ops[i].f4.a2 && ops[i].f6.a2))
+			fprintf(stderr, "    Applicable to ipv4- and ipv6-addresses.\n\n");
+		else if (ops[i].f6.a2 || ops[i].f6.a1)
+			fprintf(stderr, "    Only applicable to ipv6-addresses.\n\n");
+		else
+			fprintf(stderr, "    Only applicable to ipv4-addresses.\n\n");
+	}
+
+	fprintf(stderr,
+	        "Examples:\n\n"
+	        " Calculate a DHCP range:\n\n"
+	        "  $ %s 192.168.1.1/255.255.255.0 network add 100 print add 150 print\n"
+			"  192.168.1.100\n"
+			"  192.168.1.250\n\n"
+			" Count number of prefixes:\n\n"
+			"  $ %s 2001:0DB8:FDEF::/48 howmany ::/64\n"
+			"  65536\n\n",
+	        prog, prog);
+
+	exit(1);
+}
+
+static bool runop(struct cidr *a, char ***arg, int *status)
+{
+	int i;
+	char *arg1 = **arg;
+	char *arg2 = *(*arg+1);
+	struct cidr *b = NULL;
+
+	if (!arg1)
+		return false;
+
+	for (i = 0; i < sizeof(ops) / sizeof(ops[0]); i++)
+	{
+		if (!strcmp(ops[i].name, arg1))
+		{
+			if (ops[i].f4.a2 || ops[i].f6.a2)
+			{
+				if (!arg2)
+				{
+					fprintf(stderr, "'%s' requires an argument\n",
+							ops[i].name);
+
+					*status = 2;
+					return false;
+				}
+
+				b = cidr_parse(ops[i].name, arg2, a->family);
+
+				if (!b)
+				{
+					fprintf(stderr, "invalid address argument for '%s'\n",
+							ops[i].name);
+
+					*status = 3;
+					return false;
+				}
+
+				*arg += 2;
+
+				if (((a->family == AF_INET)  && !ops[i].f4.a2) ||
+					((a->family == AF_INET6) && !ops[i].f6.a2))
+				{
+					fprintf(stderr, "'%s' not supported for %s addresses\n",
+					        ops[i].name,
+							(a->family == AF_INET) ? "ipv4" : "ipv6");
+
+					*status = 5;
+					return false;
+				}
+
+				*status = !((a->family == AF_INET) ? ops[i].f4.a2(a, b)
+				                                   : ops[i].f6.a2(a, b));
+
+				return true;
+			}
+			else
+			{
+				*arg += 1;
+
+				if (((a->family == AF_INET)  && !ops[i].f4.a1) ||
+					((a->family == AF_INET6) && !ops[i].f6.a1))
+				{
+					fprintf(stderr, "'%s' not supported for %s addresses\n",
+					        ops[i].name,
+							(a->family == AF_INET) ? "ipv4" : "ipv6");
+
+					*status = 5;
+					return false;
+				}
+
+				*status = !((a->family == AF_INET) ? ops[i].f4.a1(a)
+				                                   : ops[i].f6.a1(a));
+
+				return true;
+			}
+		}
+	}
+
+	return false;
+}
+
+int main(int argc, char **argv)
+{
+	int status = 0;
+	char **arg = argv+2;
+	struct cidr *a;
+
+	if (argc < 3)
+		usage(argv[0]);
+
+	a = strchr(argv[1], ':') ? cidr_parse6(argv[1]) : cidr_parse4(argv[1]);
+
+	if (!a)
+		usage(argv[0]);
+
+	while (runop(a, &arg, &status));
+
+	if (*arg)
+	{
+		fprintf(stderr, "unknown operation '%s'\n", *arg);
+		exit(6);
+	}
+
+	if (!printed && (status < 2))
+	{
+		if (a->family == AF_INET)
+			cidr_print4(a);
+		else
+			cidr_print6(a);
+	}
+
+	exit(status);
+}