OpenWrt – Rev 1
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/*
* 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.v4, sizeof(addr->buf.v6), "%s", s);
addr->family = AF_INET6;
if ((p = strchr(addr->buf.v4, '/')) != 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.v4+1)
memset(&addr->addr.v6, 0, sizeof(addr->addr.v6));
else if (inet_pton(AF_INET6, addr->buf.v4, &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 cidr *n = cidr_clone(a);
struct in6_addr *x = &n->addr.v6;
struct in6_addr *y = &b->addr.v6;
uint8_t i = (128 - n->prefix) / 8;
uint8_t m = ~((1 << ((128 - n->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 >= n->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);
}