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/* IP4 address parsing routines
*/
#include "ip4addr.h"
#define digit(c) ((c) >= '0' && (c) <= '9')
#define d2n(c) ((c) - '0')
/* cret(): returns v if last byte is \0, or else
* either sets *np to point to the last byte and
* returns v, or return -1 */
#define cret(v, np, s) ((np) ? *(np) = (char*)(s), (v) : *(s) ? -1 : (v))
/* eret(): returns -1 and sets *np if np is non-NULL */
#define eret(np, s) ((np) ? *(np) = (char*)(s), -1 : -1)
static int ip4mbits(const char *s, char **np) {
/* helper routine for ip4cidr() and ip4range() */
int bits;
if (!digit(*s))
return eret(np, s - 1);
bits = d2n(*s++);
while(digit(*s))
if ((bits = bits * 10 + d2n(*s++)) > 32)
return eret(np, s - 1);
/*if (!bits) return eret(np, s - 1); allow /0 mask too */
return cret(bits, np, s);
}
/* parse a prefix, return # of bits (8,16,24 or 32)
* or <0 on error. Can't return 0. */
int ip4prefix(const char *s, ip4addr_t *ap, char **np) {
ip4addr_t o;
*ap = 0;
#define ip4oct(bits) \
if (!digit(*s)) \
return eret(np, s); \
o = d2n(*s++); \
while(digit(*s)) \
if ((o = o * 10 + d2n(*s++)) > 255) \
return eret(np, s - 1); \
*ap |= o << bits
ip4oct(24);
if (*s != '.') return cret(8, np, s);
++s;
ip4oct(16);
if (*s != '.') return cret(16, np, s);
++s;
ip4oct(8);
if (*s != '.') return cret(24, np, s);
++s;
ip4oct(0);
return cret(32, np, s);
#undef ip4oct
}
/* Parse ip4 CIDR range in `s', store base
* in *ap and return number of bits (may be 0)
* or <0 on error.
* To zero hostpart:
* *ap &= ip4mask(bits)
* where bits is the return value
*/
int ip4cidr(const char *s, ip4addr_t *ap, char **np) {
int bits = ip4prefix(s, ap, (char**)&s);
if (bits < 0) /* error */
return eret(np, s);
else if (*s == '/') /* probably /bits */
return ip4mbits(s + 1, np);
else if (bits == 8) /* disallow bare numbers */
return eret(np, s);
else
return cret(bits, np, s);
}
/* Parse ip4 range or CIDR in `s',
* store start in *ap and end in *bp,
* return
* bits (may be 0) if that was CIDR or prefix,
* 32 if plain range,
* <0 on error.
* *ap may have non-zero hostpart on
* return and should be adjusted as
* *ap &= ip4mask(bits)
* where bits is the return value.
*/
int ip4range(const char *s, ip4addr_t *ap, ip4addr_t *bp, char **np) {
int bits = ip4prefix(s, ap, (char**)&s);
if (bits < 0)
return eret(np, s);
else if (*s == '-') { /* a-z */
int bbits = ip4prefix(s + 1, bp, (char**)&s);
if (bbits < 0) return eret(np, s);
if (bbits == 8) { /* treat 127.0.0.1-2 as 127.0.0.1-127.0.0.2 */
*bp = (*bp >> (bits - 8)) | (*ap & ip4mask(bits - 8));
bbits = bits;
}
else if (bbits != bits)
/* disallow weird stuff like 1.2-1.2.3.4 */
return eret(np, s);
if (bbits != 32) /* complete last octets */
*bp |= ~ip4mask(bbits);
if (*ap > *bp) return eret(np, s);
return cret(32, np, s);
}
else {
if (*s == '/') { /* /bits */
bits = ip4mbits(s + 1, (char**)&s);
if (bits < 0) return eret(np, s);
}
else if (bits == 8)
/* disallow bare numbers - use /8 */
return eret(np, s);
*bp = *ap | ~ip4mask(bits);
return cret(bits, np, s);
}
}
/* traditional inet_aton/inet_addr. Werid:
* 127.1 = 127.0.0.1
* 1 = 0.0.0.1!!! - but here we go...
* return #bits in _prefix_ (8,16,24 or 32), or <0 on error.
*/
int ip4addr(const char *s, ip4addr_t *ap, char **np) {
int bits = ip4prefix(s, ap, np);
switch(bits) {
case 8: /* what a werid case! */
*ap >>= 24;
break;
case 16:
*ap = (*ap & 0xff000000u) | ((*ap >> 16) & 255);
break;
case 24:
*ap = (*ap & 0xffff0000u) | ((*ap >> 8) & 255);
break;
}
return bits;
}
#ifdef TEST
#include <stdio.h>
int main(int argc, char **argv) {
int i;
ip4addr_t a, b;
int bits;
char *np;
#define octets(x) (x)>>24,((x)>>16)&255,((x)>>8)&255,(x)&255
#define IPFMT "%u.%u.%u.%u"
for(i = 1; i < argc; ++i) {
char *s = argv[i];
printf("%s:\n", s);
#define PFX " pfx : bits=%d "
#define ADDR " addr : bits=%d "
#define CIDR " cidr : bits=%d "
#define RANGE " range: bits=%d "
#define HP(a,bits) (a & ~ip4mask(bits) ? " (non-zero hostpart)" : "")
bits = ip4prefix(s, &a, NULL);
if (bits < 0) printf(" pfx : err\n");
else printf(" pfx : bits=%d " IPFMT "\n", bits, octets(a));
bits = ip4prefix(s, &a, &np);
if (bits < 0) printf(" pfx : err tail=`%s'\n", np);
else
printf(" pfx : bits=%d " IPFMT " tail=`%s'\n", bits, octets(a), np);
bits = ip4addr(s, &a, NULL);
if (bits < 0) printf(" addr : err\n");
else printf(" addr : bits=%d " IPFMT "\n", bits, octets(a));
bits = ip4addr(s, &a, &np);
if (bits < 0) printf(" addr : err tail=`%s'\n", np);
else printf(" addr : bits=%d " IPFMT " tail=`%s'\n", bits, octets(a), np);
bits = ip4cidr(s, &a, NULL);
if (bits < 0) printf(" cidr : err\n");
else
printf(" cidr : bits=%d " IPFMT "%s\n", bits, octets(a), HP(a,bits));
bits = ip4cidr(argv[i], &a, &np);
if (bits < 0) printf(" cidr : err tail=`%s'\n", np);
else
printf(" cidr : bits=%d " IPFMT " " IPFMT " tail=`%s'%s\n",
bits, octets(a), octets(a&ip4mask(bits)), np, HP(a,bits));
bits = ip4range(s, &a, &b, NULL);
if (bits < 0) printf(" range: err\n");
else
printf(" range: bits=%d " IPFMT "-" IPFMT "%s\n",
bits, octets(a), octets(b), HP(a,bits));
bits = ip4range(s, &a, &b, &np);
if (bits < 0) printf(" range: err tail=`%s'\n", np);
else
printf(" range: bits=%d " IPFMT "-" IPFMT " tail=`%s'%s\n",
bits, octets(a), octets(b), np, HP(a,bits));
}
return 0;
}
#endif
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