lib: prefix2sockunion, prefix_common_bits helper functions

prefix2sockunion converts a struct prefix* to a union sockunion *;
prefix_common_bits counts the number of common bits in the prefix's
address part.
This commit is contained in:
David Lamparter 2010-02-02 20:16:35 +01:00 committed by Denis Ovsienko
parent 681b84e8f5
commit 17e52061ba
2 changed files with 56 additions and 0 deletions

View File

@ -181,6 +181,46 @@ prefix_cmp (const struct prefix *p1, const struct prefix *p2)
return 0; return 0;
} }
/*
* Count the number of common bits in 2 prefixes. The prefix length is
* ignored for this function; the whole prefix is compared. If the prefix
* address families don't match, return -1; otherwise the return value is
* in range 0 ... maximum prefix length for the address family.
*/
int
prefix_common_bits (const struct prefix *p1, const struct prefix *p2)
{
int pos, bit;
int length = 0;
u_char xor;
/* Set both prefix's head pointer. */
const u_char *pp1 = (const u_char *)&p1->u.prefix;
const u_char *pp2 = (const u_char *)&p2->u.prefix;
if (p1->family == AF_INET)
length = IPV4_MAX_BYTELEN;
#ifdef HAVE_IPV6
if (p1->family == AF_INET6)
length = IPV6_MAX_BYTELEN;
#endif
if (p1->family != p2->family || !length)
return -1;
for (pos = 0; pos < length; pos++)
if (pp1[pos] != pp2[pos])
break;
if (pos == length)
return pos * 8;
xor = pp1[pos] ^ pp2[pos];
for (bit = 0; bit < 8; bit++)
if (xor & (1 << (7 - bit)))
break;
return pos * 8 + bit;
}
/* Return prefix family type string. */ /* Return prefix family type string. */
const char * const char *
prefix_family_str (const struct prefix *p) prefix_family_str (const struct prefix *p)
@ -570,6 +610,20 @@ sockunion2hostprefix (const union sockunion *su)
return NULL; return NULL;
} }
void
prefix2sockunion (const struct prefix *p, union sockunion *su)
{
memset (su, 0, sizeof (*su));
su->sa.sa_family = p->family;
if (p->family == AF_INET)
su->sin.sin_addr = p->u.prefix4;
#ifdef HAVE_IPV6
if (p->family == AF_INET6)
memcpy (&su->sin6.sin6_addr, &p->u.prefix6, sizeof (struct in6_addr));
#endif /* HAVE_IPV6 */
}
int int
prefix_blen (const struct prefix *p) prefix_blen (const struct prefix *p)
{ {

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@ -157,12 +157,14 @@ extern int prefix2str (const struct prefix *, char *, int);
extern int prefix_match (const struct prefix *, const struct prefix *); extern int prefix_match (const struct prefix *, const struct prefix *);
extern int prefix_same (const struct prefix *, const struct prefix *); extern int prefix_same (const struct prefix *, const struct prefix *);
extern int prefix_cmp (const struct prefix *, const struct prefix *); extern int prefix_cmp (const struct prefix *, const struct prefix *);
extern int prefix_common_bits (const struct prefix *, const struct prefix *);
extern void prefix_copy (struct prefix *dest, const struct prefix *src); extern void prefix_copy (struct prefix *dest, const struct prefix *src);
extern void apply_mask (struct prefix *); extern void apply_mask (struct prefix *);
extern struct prefix *sockunion2prefix (const union sockunion *dest, extern struct prefix *sockunion2prefix (const union sockunion *dest,
const union sockunion *mask); const union sockunion *mask);
extern struct prefix *sockunion2hostprefix (const union sockunion *); extern struct prefix *sockunion2hostprefix (const union sockunion *);
extern void prefix2sockunion (const struct prefix *, union sockunion *);
extern struct prefix_ipv4 *prefix_ipv4_new (void); extern struct prefix_ipv4 *prefix_ipv4_new (void);
extern void prefix_ipv4_free (struct prefix_ipv4 *); extern void prefix_ipv4_free (struct prefix_ipv4 *);