Hello,
The following patch seems appropriate to apply
to fix the kernel ip6_sprintf() function.
What it is doing is ensuring that when we
abbreviate addresses that the longest string
of zeros is shortend, not the first run of
zeros.
Our internal commit log is:
problem:
Unification of IPv6 address representation
fix:
recommended format of text representing an IPv6 address
is summarized as follows.
1. omit leading zeros
2. "::" used to their maximum extent whenever possible
3. "::" used where shortens address the most
4. "::" used in the former part in case of a tie breaker
5. do not shorten one 16 bit 0 field
6. use lower case
Present code in ip6_sprintf() is following rules 1,2,5,6.
Adding fix for following other rules also.For following
rules 3 and 4, finding out the index where to replace zero's
with '::' and using that index.
References:
http://tools.ietf.org/html/draft-ietf-6man-text-addr-representation-04.html
Diff is attached in text format.
--
- Alfred Perlstein
.- AMA, VMOA #5191, 03 vmax, 92 gs500, 85 ch250, 07 zx10
.- FreeBSD committer
Index: in6.c
===================================================================
--- in6.c (revision 207329)
+++ in6.c (working copy)
@@ -61,7 +61,7 @@
*/
#include <sys/cdefs.h>
-__FBSDID("$FreeBSD$");
+__FBSDID("$FreeBSD: head/sys/netinet6/in6.c 207268 2010-04-27 09:47:14Z kib $");
#include "opt_compat.h"
#include "opt_inet.h"
@@ -1898,7 +1898,7 @@
char *
ip6_sprintf(char *ip6buf, const struct in6_addr *addr)
{
- int i;
+ int i, cnt = 0, maxcnt = 0, idx = 0, index = 0;
char *cp;
const u_int16_t *a = (const u_int16_t *)addr;
const u_int8_t *d;
@@ -1907,6 +1907,23 @@
cp = ip6buf;
for (i = 0; i < 8; i++) {
+ if (*(a + i) == 0) {
+ cnt++;
+ if (cnt == 1)
+ idx = i;
+ }
+ else if (maxcnt < cnt) {
+ maxcnt = cnt;
+ index = idx;
+ cnt = 0;
+ }
+ }
+ if (maxcnt < cnt) {
+ maxcnt = cnt;
+ index = idx;
+ }
+
+ for (i = 0; i < 8; i++) {
if (dcolon == 1) {
if (*a == 0) {
if (i == 7)
@@ -1917,7 +1934,7 @@
dcolon = 2;
}
if (*a == 0) {
- if (dcolon == 0 && *(a + 1) == 0) {
+ if (dcolon == 0 && *(a + 1) == 0 && i == index) {
if (i == 0)
*cp++ = ':';
*cp++ = ':';
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