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Hi!
options rotate
in /etc/resolv.conf doesn't work, at least if RES_STAYOPEN is not set.
That's because res_nclose clears nsinit and on next res_send nsaddrs
array is reinitialized.
The following patch tries to fix this, by using nsmap array;
nsmap[X] = Y means that nsaddrs[X] corresponds to nsaddr_list[Y]
if Y < MAXNS, nsaddrs[X] is unused slot if Y == MAXNS and nsaddrs[X]
is an IPv6 address if Y == MAXNS + 1 (to speed things up, so that sock_eq
doesn't have to be called that often).
It also should prevent problems if res_state is initialized with some IPv6
nameservers and then some IPv4 are added in the public part of the
structure, such that sum of both is > MAXNS. Also it should close sockets
even if there are holes, such as if res_state is initialized with
IPv4, IPv4, IPv6 ns and then the public part of the structure is changed
for just one or zero IPv4 nameservers.
2002-05-21 Jakub Jelinek <jakub@redhat.com>
* resolv/resolv.h (struct __res_state): Remove unused nstimes.
Add nsmap.
* resolv/res_init.c (__res_vinit): Initialize nsmap array.
Remove nstimes setting.
(res_nclose): Check all MAXNS nameservers with non-NULL nsaddrs.
* resolv/res_send.c (res_nsend): Don't close unconditionally if
there is mix of IPv6 and IPv4 nameservers.
Use nsmap array to find free slots and preserve nameserver ordering.
Fix RES_ROTATE.
--- libc/resolv/res_init.c.jj Thu Aug 23 18:49:01 2001
+++ libc/resolv/res_init.c Tue May 21 18:03:44 2002
@@ -182,8 +182,10 @@ __res_vinit(res_state statp, int preinit
statp->_u._ext.nscount = 0;
#ifdef _LIBC
statp->_u._ext.nscount6 = 0;
- for (n = 0; n < MAXNS; n++)
- statp->_u._ext.nsaddrs[n] = NULL;
+ for (n = 0; n < MAXNS; n++) {
+ statp->_u._ext.nsaddrs[n] = NULL;
+ statp->_u._ext.nsmap[n] = MAXNS;
+ }
#endif
/* Allow user to override the local domain definition */
@@ -323,8 +325,8 @@ __res_vinit(res_state statp, int preinit
sa6->sin6_family = AF_INET6;
sa6->sin6_port = htons(NAMESERVER_PORT);
statp->_u._ext.nsaddrs[nservall] = sa6;
- statp->_u._ext.nstimes[nservall] = RES_MAXTIME;
statp->_u._ext.nssocks[nservall] = -1;
+ statp->_u._ext.nsmap[nservall] = MAXNS + 1;
nservall++;
}
}
@@ -537,16 +539,14 @@ res_nclose(res_state statp) {
statp->_flags &= ~(RES_F_VC | RES_F_CONN);
}
#ifdef _LIBC
- for (ns = 0; ns < statp->_u._ext.nscount + statp->_u._ext.nscount6;
- ns++)
+ for (ns = 0; ns < MAXNS; ns++)
#else
for (ns = 0; ns < statp->_u._ext.nscount; ns++)
#endif
- {
- if (statp->_u._ext.nssocks[ns] != -1) {
+ if (statp->_u._ext.nsaddrs[ns]
+ && statp->_u._ext.nssocks[ns] != -1) {
(void) __close(statp->_u._ext.nssocks[ns]);
statp->_u._ext.nssocks[ns] = -1;
}
- }
statp->_u._ext.nsinit = 0;
}
--- libc/resolv/res_send.c.jj Fri Feb 16 11:53:48 2001
+++ libc/resolv/res_send.c Tue May 21 19:06:40 2002
@@ -400,12 +400,15 @@ res_nsend(res_state statp,
if (EXT(statp).nscount != statp->nscount)
needclose++;
else
- for (ns = 0; ns < statp->nscount; ns++)
#ifdef _LIBC
- if (!sock_eq((struct sockaddr_in6 *)
- &statp->nsaddr_list[ns],
- EXT(statp).nsaddrs[ns]))
+ for (ns = 0; ns < MAXNS; ns++) {
+ unsigned int map = EXT(statp).nsmap[ns];
+ if (map < MAXNS
+ && !sock_eq((struct sockaddr_in6 *)
+ &statp->nsaddr_list[map],
+ EXT(statp).nsaddrs[ns]))
#else
+ for (ns = 0; ns < statp->nscount; ns++) {
if (!sock_eq(&statp->nsaddr_list[ns],
&EXT(statp).nsaddrs[ns]))
#endif
@@ -413,6 +416,7 @@ res_nsend(res_state statp,
needclose++;
break;
}
+ }
if (needclose)
res_nclose(statp);
}
@@ -422,20 +426,34 @@ res_nsend(res_state statp,
*/
if (EXT(statp).nsinit == 0) {
#ifdef _LIBC
- n = 0;
-#endif
- for (ns = 0; ns < statp->nscount; ns++) {
-#ifdef _LIBC
- /* find a hole */
- while ((n < MAXNS) &&
- (EXT(statp).nsaddrs[n] != NULL) &&
- (EXT(statp).nsaddrs[n]->sin6_family == AF_INET6) &&
- !IN6_IS_ADDR_V4MAPPED(
- &EXT(statp).nsaddrs[n]->sin6_addr))
- n++;
- if (n == MAXNS)
- break;
+ unsigned char map[MAXNS];
+ memset (map, MAXNS, sizeof (map));
+ for (n = 0; n < MAXNS; n++) {
+ ns = EXT(statp).nsmap[n];
+ if (ns < statp->nscount)
+ map[ns] = n;
+ else if (ns < MAXNS) {
+ free(EXT(statp).nsaddrs[n]);
+ EXT(statp).nsaddrs[n] = NULL;
+ EXT(statp).nsmap[n] = MAXNS;
+ }
+ }
+ n = statp->nscount;
+ if (statp->nscount > EXT(statp).nscount)
+ for (n = EXT(statp).nscount, ns = 0;
+ n < statp->nscount; n++) {
+ while (ns < MAXNS
+ && EXT(statp).nsmap[ns] != MAXNS)
+ ns++;
+ if (ns == MAXNS)
+ break;
+ EXT(statp).nsmap[ns] = n;
+ map[n] = ns++;
+ }
+ EXT(statp).nscount = n;
+ for (ns = 0; ns < EXT(statp).nscount; ns++) {
+ n = map[ns];
if (EXT(statp).nsaddrs[n] == NULL)
EXT(statp).nsaddrs[n] =
malloc(sizeof (struct sockaddr_in6));
@@ -443,31 +461,18 @@ res_nsend(res_state statp,
memcpy(EXT(statp).nsaddrs[n],
&statp->nsaddr_list[ns],
sizeof (struct sockaddr_in));
- EXT(statp).nstimes[n] = RES_MAXTIME;
EXT(statp).nssocks[n] = -1;
n++;
}
+ }
#else
+ for (ns = 0; ns < statp->nscount; ns++) {
EXT(statp).nsaddrs[ns] = statp->nsaddr_list[ns];
- EXT(statp).nstimes[ns] = RES_MAXTIME;
EXT(statp).nssocks[ns] = -1;
-#endif
- }
- EXT(statp).nscount = statp->nscount;
- EXT(statp).nsinit = 1;
-#ifdef _LIBC
- /* If holes left, free memory and set to NULL */
- while (n < MAXNS) {
- if ((EXT(statp).nsaddrs[n] != NULL) &&
- ((EXT(statp).nsaddrs[n]->sin6_family != AF_INET6)
- || IN6_IS_ADDR_V4MAPPED(
- &EXT(statp).nsaddrs[n]->sin6_addr))) {
- free(EXT(statp).nsaddrs[n]);
- EXT(statp).nsaddrs[n] = NULL;
- }
- n++;
}
+ EXT(statp).nscount = ns;
#endif
+ EXT(statp).nsinit = 1;
}
/*
@@ -478,12 +483,28 @@ res_nsend(res_state statp,
(statp->options & RES_BLAST) == 0) {
#ifdef _LIBC
struct sockaddr_in6 *ina;
- int lastns = statp->nscount + EXT(statp).nscount6 - 1;
+ unsigned int map;
- ina = EXT(statp).nsaddrs[0];
- for (ns = 0; ns < lastns; ns++)
- EXT(statp).nsaddrs[ns] = EXT(statp).nsaddrs[ns + 1];
- EXT(statp).nsaddrs[lastns] = ina;
+ n = 0;
+ while (n < MAXNS && EXT(statp).nsmap[n] == MAXNS)
+ n++;
+ if (n < MAXNS) {
+ ina = EXT(statp).nsaddrs[n];
+ map = EXT(statp).nsmap[n];
+ for (;;) {
+ ns = n + 1;
+ while (ns < MAXNS
+ && EXT(statp).nsmap[ns] == MAXNS)
+ ns++;
+ if (ns == MAXNS)
+ break;
+ EXT(statp).nsaddrs[n] = EXT(statp).nsaddrs[ns];
+ EXT(statp).nsmap[n] = EXT(statp).nsmap[ns];
+ n = ns;
+ }
+ EXT(statp).nsaddrs[n] = ina;
+ EXT(statp).nsmap[n] = map;
+ }
#else
struct sockaddr_in ina;
int lastns = statp->nscount - 1;
--- libc/resolv/resolv.h.jj Fri Feb 8 12:04:18 2002
+++ libc/resolv/resolv.h Tue May 21 15:57:47 2002
@@ -130,7 +130,7 @@ struct __res_state {
char pad[52]; /* On an i386 this means 512b total. */
struct {
u_int16_t nscount;
- u_int16_t nstimes[MAXNS]; /* ms. */
+ u_int16_t nsmap[MAXNS];
int nssocks[MAXNS];
u_int16_t nscount6;
u_int16_t nsinit;
Jakub
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