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Code Issues Releases Activity

Simplify contiguous mask checking.

Browse Source 
Suggested by:	glebius
MFC after:	2 weeks
This commit is contained in:
Alexander V. Chernikov 2013-12-17 22:16:27 +00:00
parent 88bb82e511
commit 78aed5e800
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=259528
1 changed files with 8 additions and 10 deletions
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18
sys/net/radix.c
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@ -484,13 +484,13 @@ rn_insert(v_arg, head, dupentry, nodes)
struct radix_node *
rn_addmask(void *n_arg, struct radix_node_head *maskhead, int search, int skip)
{
caddr_t netmask = (caddr_t)n_arg;
register struct radix_node *x;
register caddr_t cp, cplim;
register int b = 0, mlen, j;
unsigned char *netmask = n_arg;
unsigned char *cp, *cplim;
struct radix_node *x;
int b = 0, mlen, j;
int maskduplicated, isnormal;
struct radix_node *saved_x;
char addmask_key[RADIX_MAX_KEY_LEN];
unsigned char addmask_key[RADIX_MAX_KEY_LEN];
if ((mlen = LEN(netmask)) > RADIX_MAX_KEY_LEN)
mlen = RADIX_MAX_KEY_LEN;
@ -532,20 +532,18 @@ rn_addmask(void *n_arg, struct radix_node_head *maskhead, int search, int skip)
* Calculate index of mask, and check for normalcy.
* First find the first byte with a 0 bit, then if there are
* more bits left (remember we already trimmed the trailing 0's),
* the pattern must be one of those in normal_chars[], or we have
* the bits should be contiguous, otherwise we have got
* a non-contiguous mask.
*/
#define CONTIG(_c) (((~(_c) + 1) & (_c)) == (unsigned char)(~(_c) + 1))
cplim = netmask + mlen;
isnormal = 1;
for (cp = netmask + skip; (cp < cplim) && *(u_char *)cp == 0xff;)
cp++;
if (cp != cplim) {
static char normal_chars[] = {
0, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff};
for (j = 0x80; (j & *cp) != 0; j >>= 1)
b++;
if (*cp != normal_chars[b] || cp != (cplim - 1))
if (!CONTIG(*cp) || cp != (cplim - 1))
isnormal = 0;
}
b += (cp - netmask) << 3;