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/*
* The mrouted program is covered by the license in the accompanying file
* named "LICENSE.mrouted". Use of the mrouted program represents acceptance of
* the terms and conditions listed in that file.
*
* The mrouted program is COPYRIGHT 1989 by The Board of Trustees of
* Leland Stanford Junior University.
*
*
* inet.c,v 3.8.4.1 1997/01/29 19:49:33 fenner Exp
*/
#define C(x) ((x) & 0xff)
#include "defs.h"
/*
* Exported variables.
*/
char s1[MAX_INET_BUF_LEN]; /* buffers to hold the string representations */
char s2[MAX_INET_BUF_LEN]; /* of IP addresses, to be passed to inet_fmt() */
char s3[MAX_INET_BUF_LEN];
char s4[MAX_INET_BUF_LEN];
/*
* Verify that a given IP address is credible as a host address.
* (Without a mask, cannot detect addresses of the form {subnet,0} or
* {subnet,-1}.)
*/
int inet_valid_host(u_int32 naddr)
{
u_int32 addr;
addr = ntohl(naddr);
return (!(IN_MULTICAST(addr) ||
IN_BADCLASS (addr) ||
(addr & 0xff000000) == 0));
}
/*
* Verify that a given netmask is plausible;
* make sure that it is a series of 1's followed by
* a series of 0's with no discontiguous 1's.
*/
int
inet_valid_mask(mask)
u_int32 mask;
{
if (~(((mask & -mask) - 1) | mask) != 0) {
/* Mask is not contiguous */
return (FALSE);
}
return (TRUE);
}
/*
* Verify that a given subnet number and mask pair are credible.
*
* With CIDR, almost any subnet and mask are credible. mrouted still
* can't handle aggregated class A's, so we still check that, but
* otherwise the only requirements are that the subnet address is
* within the [ABC] range and that the host bits of the subnet
* are all 0.
*/
int
inet_valid_subnet(nsubnet, nmask)
u_int32 nsubnet, nmask;
{
register u_int32 subnet, mask;
subnet = ntohl(nsubnet);
mask = ntohl(nmask);
if ((subnet & mask) != subnet)
return (FALSE);
if (subnet == 0)
return (mask == 0);
if (IN_CLASSA(subnet)) {
if (mask < 0xff000000 ||
(subnet & 0xff000000) == 0x7f000000 ||
(subnet & 0xff000000) == 0x00000000) return (FALSE);
}
else if (IN_CLASSD(subnet) || IN_BADCLASS(subnet)) {
/* Above Class C address space */
return (FALSE);
}
if (subnet & ~mask) {
/* Host bits are set in the subnet */
return (FALSE);
}
if (!inet_valid_mask(mask)) {
/* Netmask is not contiguous */
return (FALSE);
}
return (TRUE);
}
/*
* Convert an IP address in u_int32 (network) format into a printable string.
*/
char *inet_fmt(u_int32 addr, char *s, size_t len)
{
u_char *a;
a = (u_char *)&addr;
snprintf(s, len, "%u.%u.%u.%u", a[0], a[1], a[2], a[3]);
return s;
}
/*
* Convert the printable string representation of an IP address into the
* u_int32 (network) format. Return 0xffffffff on error. (To detect the
* legal address with that value, you must explicitly compare the string
* with "255.255.255.255".)
* The return value is in network order.
*/
u_int32
inet_parse(s, n)
char *s;
int n;
{
u_int32 a = 0;
u_int a0 = 0, a1 = 0, a2 = 0, a3 = 0;
int i;
char c;
i = sscanf(s, "%u.%u.%u.%u%c", &a0, &a1, &a2, &a3, &c);
if (i < n || i > 4 || a0 > 255 || a1 > 255 || a2 > 255 || a3 > 255)
return (0xffffffff);
((u_char *)&a)[0] = a0;
((u_char *)&a)[1] = a1;
((u_char *)&a)[2] = a2;
((u_char *)&a)[3] = a3;
return (a);
}
/*
* inet_cksum extracted from:
* P I N G . C
*
* Author -
* Mike Muuss
* U. S. Army Ballistic Research Laboratory
* December, 1983
* Modified at Uc Berkeley
*
* (ping.c) Status -
* Public Domain. Distribution Unlimited.
*
* I N _ C K S U M
*
* Checksum routine for Internet Protocol family headers (C Version)
*
*/
int
inet_cksum(addr, len)
u_int16 *addr;
u_int len;
{
register int nleft = (int)len;
register u_int16 *w = addr;
u_int16 answer = 0;
register int sum = 0;
/*
* Our algorithm is simple, using a 32 bit accumulator (sum),
* we add sequential 16 bit words to it, and at the end, fold
* back all the carry bits from the top 16 bits into the lower
* 16 bits.
*/
while (nleft > 1) {
sum += *w++;
nleft -= 2;
}
/* mop up an odd byte, if necessary */
if (nleft == 1) {
*(u_char *) (&answer) = *(u_char *)w ;
sum += answer;
}
/*
* add back carry outs from top 16 bits to low 16 bits
*/
sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */
sum += (sum >> 16); /* add carry */
answer = ~sum; /* truncate to 16 bits */
return (answer);
}
/*
* Called by following netname() to create a mask specified network address.
*/
void
trimdomain(cp)
char *cp;
{
static char domain[MAXHOSTNAMELEN + 1];
static int first = 1;
char *s;
if (first) {
first = 0;
if (gethostname(domain, MAXHOSTNAMELEN) == 0 &&
(s = strchr(domain, '.')))
(void) strlcpy(domain, s + 1, sizeof(domain));
else
domain[0] = 0;
}
if (domain[0]) {
while ((cp = strchr(cp, '.'))) {
if (!strcasecmp(cp + 1, domain)) {
*cp = 0; /* hit it */
break;
} else {
cp++;
}
}
}
}
static u_long
forgemask(a)
u_long a;
{
u_long m;
if (IN_CLASSA(a))
m = IN_CLASSA_NET;
else if (IN_CLASSB(a))
m = IN_CLASSB_NET;
else
m = IN_CLASSC_NET;
return (m);
}
static void domask(char *dst, size_t len, u_long addr, u_long mask)
{
int b, i;
if (!mask || (forgemask(addr) == mask)) {
*dst = '\0';
return;
}
i = 0;
for (b = 0; b < 32; b++)
if (mask & (1 << b)) {
int bb;
i = b;
for (bb = b+1; bb < 32; bb++)
if (!(mask & (1 << bb))) {
i = -1; /* noncontig */
break;
}
break;
}
if (i == -1)
snprintf(dst, len, "&0x%lx", mask);
else
snprintf(dst, len, "/%d", 32 - i);
}
/*
* Return the name of the network whose address is given.
* The address is assumed to be that of a net or subnet, not a host.
*/
char *netname(u_int32 addr, u_int32 mask)
{
static char line[MAXHOSTNAMELEN + 4];
u_int32 omask;
u_int32 i;
i = ntohl(addr);
omask = mask = ntohl(mask);
if ((i & 0xffffff) == 0)
snprintf(line, sizeof(line), "%u", C(i >> 24));
else if ((i & 0xffff) == 0)
snprintf(line, sizeof(line), "%u.%u", C(i >> 24) , C(i >> 16));
else if ((i & 0xff) == 0)
snprintf(line, sizeof(line), "%u.%u.%u", C(i >> 24), C(i >> 16), C(i >> 8));
else
snprintf(line, sizeof(line), "%u.%u.%u.%u", C(i >> 24),
C(i >> 16), C(i >> 8), C(i));
domask(line + strlen(line), sizeof(line) - strlen(line), i, omask);
return line;
}
/**
* Local Variables:
* version-control: t
* indent-tabs-mode: t
* c-file-style: "ellemtel"
* c-basic-offset: 4
* End:
*/
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