owipcalc: import from base
authorAdrian Schmutzler <freifunk@adrianschmutzler.de>
Fri, 22 Jan 2021 16:12:53 +0000 (17:12 +0100)
committerAdrian Schmutzler <freifunk@adrianschmutzler.de>
Fri, 22 Jan 2021 16:12:53 +0000 (17:12 +0100)
This is a helpful utility, but it does not have any dependencies
in base repository. Move it to packages feed.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
net/owipcalc/Makefile [new file with mode: 0644]
net/owipcalc/src/owipcalc.c [new file with mode: 0644]

diff --git a/net/owipcalc/Makefile b/net/owipcalc/Makefile
new file mode 100644 (file)
index 0000000..dc68a03
--- /dev/null
@@ -0,0 +1,44 @@
+#
+# Copyright (C) 2012 Jo-Philipp Wich <jo@mein.io>
+#
+# This is free software, licensed under the Apache 2 license.
+#
+
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=owipcalc
+PKG_RELEASE:=5
+PKG_LICENSE:=Apache-2.0
+
+include $(INCLUDE_DIR)/package.mk
+
+
+define Package/owipcalc
+  SECTION:=utils
+  CATEGORY:=Utilities
+  TITLE:=Simple IPv4/IPv6 address calculator
+  MAINTAINER:=Jo-Philipp Wich <jo@mein.io>
+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/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/net/owipcalc/src/owipcalc.c b/net/owipcalc/src/owipcalc.c
new file mode 100644 (file)
index 0000000..5ed609f
--- /dev/null
@@ -0,0 +1,950 @@
+/*
+ * owipcalc - OpenWrt IP Calculator
+ *
+ *   Copyright (C) 2012 Jo-Philipp Wich <jo@mein.io>
+ *
+ *  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:255.255.255.255/128 ")];
+       } buf;
+       struct cidr *next;
+};
+
+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 *stack = NULL;
+
+#define qprintf(...) \
+       do { \
+               if (!quiet) printf(__VA_ARGS__); \
+               printed = true; \
+       } while(0)
+
+static void cidr_push(struct cidr *a)
+{
+       if (a)
+       {
+               a->next = stack;
+               stack = a;
+       }
+}
+
+static bool cidr_pop(struct cidr *a)
+{
+       struct cidr *old = stack;
+
+       if (old)
+       {
+               stack = stack->next;
+               free(old);
+
+               return true;
+       }
+
+       return false;
+}
+
+static struct cidr * cidr_clone(struct cidr *a)
+{
+       struct cidr *b = malloc(sizeof(*b));
+
+       if (!b)
+       {
+               fprintf(stderr, "out of memory\n");
+               exit(255);
+       }
+
+       memcpy(b, a, sizeof(*b));
+       cidr_push(b);
+
+       return b;
+}
+
+
+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);
+
+       struct cidr *n = cidr_clone(a);
+
+       if ((n->family != AF_INET) || (b->family != AF_INET))
+               return false;
+
+       if ((uint32_t)(x + y) < x)
+       {
+               fprintf(stderr, "overflow during 'add'\n");
+               return false;
+       }
+
+       n->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);
+
+       struct cidr *n = cidr_clone(a);
+
+       if ((n->family != AF_INET) || (b->family != AF_INET))
+               return false;
+
+       if ((uint32_t)(x - y) > x)
+       {
+               fprintf(stderr, "underflow during 'sub'\n");
+               return false;
+       }
+
+       n->addr.v4.s_addr = htonl(x - y);
+       return true;
+}
+
+static bool cidr_network4(struct cidr *a)
+{
+       struct cidr *n = cidr_clone(a);
+
+       n->addr.v4.s_addr &= htonl(~((1 << (32 - n->prefix)) - 1));
+       n->prefix = 32;
+
+       return true;
+}
+
+static bool cidr_broadcast4(struct cidr *a)
+{
+       struct cidr *n = cidr_clone(a);
+
+       n->addr.v4.s_addr |= htonl(((1 << (32 - n->prefix)) - 1));
+       n->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));
+
+       if (printed)
+               qprintf(" ");
+
+       if ((b->prefix >= a->prefix) && (net1 == net2))
+       {
+               qprintf("1");
+               return true;
+       }
+       else
+       {
+               qprintf("0");
+               return false;
+       }
+}
+
+static bool cidr_netmask4(struct cidr *a)
+{
+       struct cidr *n = cidr_clone(a);
+
+       n->addr.v4.s_addr = htonl(~((1 << (32 - n->prefix)) - 1));
+       n->prefix = 32;
+
+       return true;
+}
+
+static bool cidr_private4(struct cidr *a)
+{
+       uint32_t x = ntohl(a->addr.v4.s_addr);
+
+       if (printed)
+               qprintf(" ");
+
+       if (((x >= 0x0A000000) && (x <= 0x0AFFFFFF)) ||
+           ((x >= 0xAC100000) && (x <= 0xAC1FFFFF)) ||
+           ((x >= 0xC0A80000) && (x <= 0xC0A8FFFF)))
+       {
+               qprintf("1");
+               return true;
+       }
+       else
+       {
+               qprintf("0");
+               return false;
+       }
+}
+
+static bool cidr_linklocal4(struct cidr *a)
+{
+       uint32_t x = ntohl(a->addr.v4.s_addr);
+
+       if (printed)
+               qprintf(" ");
+
+       if ((x >= 0xA9FE0000) && (x <= 0xA9FEFFFF))
+       {
+               qprintf("1");
+               return true;
+       }
+       else
+       {
+               qprintf("0");
+               return false;
+       }
+}
+
+static bool cidr_prev4(struct cidr *a, struct cidr *b)
+{
+       struct cidr *n = cidr_clone(a);
+
+       n->prefix = b->prefix;
+       n->addr.v4.s_addr -= htonl(1 << (32 - b->prefix));
+
+       return true;
+}
+
+static bool cidr_next4(struct cidr *a, struct cidr *b)
+{
+       struct cidr *n = cidr_clone(a);
+
+       n->prefix = b->prefix;
+       n->addr.v4.s_addr += htonl(1 << (32 - b->prefix));
+
+       return true;
+}
+
+static bool cidr_6to4(struct cidr *a)
+{
+       struct cidr *n = cidr_clone(a);
+       uint32_t x = a->addr.v4.s_addr;
+
+       memset(&n->addr.v6.s6_addr, 0, sizeof(n->addr.v6.s6_addr));
+
+       n->family = AF_INET6;
+       n->prefix = 48;
+
+       n->addr.v6.s6_addr[0] = 0x20;
+       n->addr.v6.s6_addr[1] = 0x02;
+       n->addr.v6.s6_addr[2] = (x >> 24);
+       n->addr.v6.s6_addr[3] = (x >> 16) & 0xFF;
+       n->addr.v6.s6_addr[4] = (x >>  8) & 0xFF;
+       n->addr.v6.s6_addr[5] = x & 0xFF;
+
+       return true;
+}
+
+static bool cidr_print4(struct cidr *a)
+{
+       char *p;
+
+       if (!a || (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 (printed)
+               qprintf(" ");
+
+       qprintf("%s", p);
+
+       if (a->prefix < 32)
+               qprintf("/%u", a->prefix);
+
+       cidr_pop(a);
+
+       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 cidr *n = cidr_clone(a);
+       struct in6_addr *x = &n->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 cidr *n = cidr_clone(a);
+       struct in6_addr *x = &n->addr.v6;
+       struct in6_addr *y = &b->addr.v6;
+
+       if ((n->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_prev6(struct cidr *a, struct cidr *b)
+{
+       uint8_t idx, carry = 1, underflow = 0;
+       struct cidr *n = cidr_clone(a);
+       struct in6_addr *x = &n->addr.v6;
+
+       if (b->prefix == 0)
+       {
+               fprintf(stderr, "underflow during 'prev'\n");
+               return false;
+       }
+
+       idx = (b->prefix - 1) / 8;
+
+       do {
+               underflow = !!((x->s6_addr[idx] - carry) < 0);
+               x->s6_addr[idx] -= carry;
+               carry = underflow;
+       }
+       while (idx-- > 0);
+
+       if (carry)
+       {
+               fprintf(stderr, "underflow during 'prev'\n");
+               return false;
+       }
+
+       n->prefix = b->prefix;
+
+       return true;
+}
+
+static bool cidr_next6(struct cidr *a, struct cidr *b)
+{
+       uint8_t idx, carry = 1, overflow = 0;
+       struct cidr *n = cidr_clone(a);
+       struct in6_addr *x = &n->addr.v6;
+
+       if (b->prefix == 0)
+       {
+               fprintf(stderr, "overflow during 'next'\n");
+               return false;
+       }
+
+       idx = (b->prefix - 1) / 8;
+
+       do {
+               overflow = !!((x->s6_addr[idx] + carry) >= 256);
+               x->s6_addr[idx] += carry;
+               carry = overflow;
+       }
+       while (idx-- > 0);
+
+       if (carry)
+       {
+               fprintf(stderr, "overflow during 'next'\n");
+               return false;
+       }
+
+       n->prefix = b->prefix;
+
+       return true;
+}
+
+static bool cidr_network6(struct cidr *a)
+{
+       uint8_t i;
+       struct cidr *n = cidr_clone(a);
+
+       for (i = 0; i < (128 - n->prefix) / 8; i++)
+               n->addr.v6.s6_addr[15-i] = 0;
+
+       if ((128 - n->prefix) % 8)
+               n->addr.v6.s6_addr[15-i] &= ~((1 << ((128 - n->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;
+
+       if (printed)
+               qprintf(" ");
+
+       if ((b->prefix >= a->prefix) && (net1 == net2) &&
+           ((i == 15) || !memcmp(&x->s6_addr, &y->s6_addr, 15-i)))
+       {
+               qprintf("1");
+               return true;
+       }
+       else
+       {
+               qprintf("0");
+               return false;
+       }
+}
+
+static bool cidr_linklocal6(struct cidr *a)
+{
+       if (printed)
+               qprintf(" ");
+
+       if ((a->addr.v6.s6_addr[0] == 0xFE) &&
+           (a->addr.v6.s6_addr[1] >= 0x80) &&
+           (a->addr.v6.s6_addr[1] <= 0xBF))
+       {
+               qprintf("1");
+               return true;
+       }
+       else
+       {
+               qprintf("0");
+               return false;
+       }
+}
+
+static bool cidr_ula6(struct cidr *a)
+{
+       if (printed)
+               qprintf(" ");
+
+       if ((a->addr.v6.s6_addr[0] >= 0xFC) &&
+           (a->addr.v6.s6_addr[0] <= 0xFD))
+       {
+               qprintf("1");
+               return true;
+       }
+       else
+       {
+               qprintf("0");
+               return false;
+       }
+}
+
+static bool cidr_print6(struct cidr *a)
+{
+       char *p;
+
+       if (!a || (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 (printed)
+               qprintf(" ");
+
+       qprintf("%s", p);
+
+       if (a->prefix < 128)
+               qprintf("/%u", a->prefix);
+
+       cidr_pop(a);
+
+       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 = sum;
+                       a->addr.v4.s_addr = htonl(sum);
+               }
+               else
+               {
+                       a->family = AF_INET6;
+                       a->prefix = sum;
+
+                       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 (printed)
+               qprintf(" ");
+
+       if (b->prefix < a->prefix)
+               qprintf("0");
+       else
+               qprintf("%u", 1 << (b->prefix - a->prefix));
+
+       return true;
+}
+
+static bool cidr_prefix(struct cidr *a, struct cidr *b)
+{
+       a->prefix = b->prefix;
+       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 = "next",
+         .desc = "Advance base address to next prefix of given size",
+         .f4.a2 = cidr_next4,
+         .f6.a2 = cidr_next6 },
+
+       { .name = "prev",
+         .desc = "Lower base address to previous prefix of give size",
+         .f4.a2 = cidr_prev4,
+         .f6.a2 = cidr_prev6 },
+
+       { .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 = "prefix",
+         .desc = "Set the prefix of base address to argument",
+         .f4.a2 = cidr_prefix,
+         .f6.a2 = cidr_prefix },
+
+       { .name = "netmask",
+         .desc = "Calculate netmask of base address",
+         .f4.a1 = cidr_netmask4 },
+
+       { .name = "6to4",
+         .desc = "Calculate 6to4 prefix of given ipv4-address",
+         .f4.a1 = cidr_6to4 },
+
+       { .name = "howmany",
+         .desc = "Print amount of righ-hand prefixes that fit into 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",
+         .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",
+         .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",
+         .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",
+         .f6.a1 = cidr_ula6 },
+
+       { .name = "quiet",
+         .desc = "Suppress output, useful for test operation where the result can "
+                 "be inferred from the exit code",
+         .f4.a1 = cidr_quiet,
+         .f6.a1 = cidr_quiet },
+
+       { .name = "pop",
+         .desc = "Pop intermediate result from stack",
+         .f4.a1 = cidr_pop,
+         .f6.a1 = cidr_pop },
+
+       { .name = "print",
+         .desc = "Print intermediate result and pop it from stack, 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(char ***arg, int *status)
+{
+       int i;
+       char *arg1 = **arg;
+       char *arg2 = *(*arg+1);
+       struct cidr *a = stack;
+       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]);
+
+       cidr_push(a);
+
+       while (runop(&arg, &status));
+
+       if (*arg)
+       {
+               fprintf(stderr, "unknown operation '%s'\n", *arg);
+               exit(6);
+       }
+
+       if (!printed && (status < 2))
+       {
+               if (stack->family == AF_INET)
+                       cidr_print4(stack);
+               else
+                       cidr_print6(stack);
+       }
+
+       qprintf("\n");
+
+       exit(status);
+}