bird/lib/ipv4.c
Martin Mares 786d0bb9e7 Added ipa_class_mask() which guesses netmask for classful addressing.
For pure A/B/C class addresses it just returns the class netmask, for
subnets it tries to guess subnet mask. Please make sure the address
you pass to this function is really a valid host address (i.e., call
ipa_validate() first).
1998-07-10 08:38:29 +00:00

68 lines
1.1 KiB
C

/*
* BIRD Library -- IPv4 Address Manipulation Functions
*
* (c) 1998 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#ifndef IPV6
#include "nest/bird.h"
#include "lib/ip.h"
#include "lib/string.h"
int
ipv4_classify(u32 a)
{
u32 b = a >> 24U;
if (b && b <= 0xdf)
{
if (b == 0x7f)
return IADDR_HOST | SCOPE_HOST;
else
return IADDR_HOST | SCOPE_UNIVERSE;
}
if (b >= 0xe0 && b <= 0xef)
return IADDR_MULTICAST | SCOPE_UNIVERSE;
if (a == 0xffffffff)
return IADDR_BROADCAST | SCOPE_LINK;
return IADDR_INVALID;
}
char *
ip_ntop(ip_addr a, char *b)
{
u32 x = _I(a);
return b + bsprintf(b, "%d.%d.%d.%d",
((x >> 24) & 0xff),
((x >> 16) & 0xff),
((x >> 8) & 0xff),
(x & 0xff));
}
char *
ip_ntox(ip_addr a, char *b)
{
return b + bsprintf(b, "%08x", _I(a));
}
u32
ipv4_class_mask(u32 a)
{
u32 m;
if (a < 0x80000000)
m = 0xff000000;
if (a < 0xc0000000)
m = 0xffff0000;
else
m = 0xffffff00;
while (a & ~m)
m |= m >> 1;
return m;
}
#endif