Date: Thu, 23 Feb 2006 02:08:17 +0900 From: Hajimu UMEMOTO <ume@freebsd.org> To: Rostislav Krasny <rosti.bsd@gmail.com> Cc: freebsd-stable@freebsd.org, freebsd-stable-local@be-well.ilk.org, Yar Tikhiy <yar@comp.chem.msu.su>, dwmalone@maths.tcd.ie, des@des.no, mak@ll.mit.edu, MH@kernel32.de Subject: Re: SSH login takes very long time...sometimes Message-ID: <yge1wxvz5ha.wl%ume@mahoroba.org> In-Reply-To: <20060222024430.ad4b5c60.rosti.bsd@gmail.com> References: <59e2ee810512250841t75157e62rec9dc389ac716534@mail.gmail.com> <20051227101621.GA16276@walton.maths.tcd.ie> <86irrfoix5.fsf@xps.des.no> <20060218012029.e146e2ff.rosti.bsd@gmail.com> <20060219104912.GB20500@comp.chem.msu.su> <20060219225701.0e3e244b.rosti.bsd@gmail.com> <20060221165959.GB77513@comp.chem.msu.su> <20060222024430.ad4b5c60.rosti.bsd@gmail.com>
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Hi,
>>>>> On Wed, 22 Feb 2006 02:44:30 +0200
>>>>> Rostislav Krasny <rosti.bsd@gmail.com> said:
rosti> On Tue, 21 Feb 2006 19:59:59 +0300
rosti> Yar Tikhiy <yar@comp.chem.msu.su> wrote:
rosti> I forgot that a "search" resolver(5) parameter is useless for reverse
rosti> resolving. But that "doubling" of name->IP requests with an empty (or
rosti> root, according to resolver(5)) domain in the "search" is still a bug,
rosti> IMHO. Although it shouldn't affect the sshd.
I looked BIND9's resolver, and took the related part into our
resolver. However, it seems to me that there is still same issue in
BIND9's resolver. So, I change more bit. Please try the following
patch and let me know the result:
Index: lib/libc/net/getaddrinfo.c
diff -u -p lib/libc/net/getaddrinfo.c.orig lib/libc/net/getaddrinfo.c
--- lib/libc/net/getaddrinfo.c.orig Sat Jul 23 03:21:28 2005
+++ lib/libc/net/getaddrinfo.c Thu Feb 23 01:43:49 2006
@@ -2405,7 +2405,9 @@ res_searchN(name, target)
HEADER *hp = (HEADER *)(void *)target->answer; /*XXX*/
u_int dots;
int trailing_dot, ret, saved_herrno;
- int got_nodata = 0, got_servfail = 0, tried_as_is = 0;
+ int got_nodata = 0, got_servfail = 0, root_on_list = 0;
+ int tried_as_is = 0;
+ int searched = 0;
char abuf[MAXDNAME];
if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
@@ -2429,13 +2431,14 @@ res_searchN(name, target)
return (res_queryN(cp, target));
/*
- * If there are dots in the name already, let's just give it a try
- * 'as is'. The threshold can be set with the "ndots" option.
+ * If there are enough dots in the name, let's just give it a
+ * try 'as is'. The threshold can be set with the "ndots" option.
+ * Also, query 'as is', if there is a trailing dot in the name.
*/
saved_herrno = -1;
- if (dots >= _res.ndots) {
+ if (dots >= _res.ndots || trailing_dot) {
ret = res_querydomainN(name, NULL, target);
- if (ret > 0)
+ if (ret > 0 || trailing_dot)
return (ret);
saved_herrno = h_errno;
tried_as_is++;
@@ -2454,6 +2457,14 @@ res_searchN(name, target)
for (domain = (const char * const *)_res.dnsrch;
*domain && !done;
domain++) {
+ searched = 1;
+
+ if (domain[0][0] == '\0' ||
+ (domain[0][0] == '.' && domain[0][1] == '\0'))
+ root_on_list++;
+
+ if (root_on_list && tried_as_is)
+ continue;
ret = res_querydomainN(name, *domain, target);
if (ret > 0)
@@ -2505,11 +2516,11 @@ res_searchN(name, target)
}
/*
- * if we have not already tried the name "as is", do that now.
- * note that we do this regardless of how many dots were in the
- * name or whether it ends with a dot.
+ * If the query has not already been tried as is then try it
+ * unless RES_NOTLDQUERY is set and there were no dots.
*/
- if (!tried_as_is && (dots || !(_res.options & RES_NOTLDQUERY))) {
+ if ((dots || !searched || !(_res.options & RES_NOTLDQUERY)) &&
+ !(tried_as_is || root_on_list)) {
ret = res_querydomainN(name, NULL, target);
if (ret > 0)
return (ret);
Index: lib/libc/net/res_query.c
diff -u -p lib/libc/net/res_query.c.orig lib/libc/net/res_query.c
--- lib/libc/net/res_query.c.orig Fri Apr 15 23:42:29 2005
+++ lib/libc/net/res_query.c Thu Feb 23 01:43:49 2006
@@ -198,7 +198,9 @@ res_search(name, class, type, answer, an
char tmp[MAXDNAME];
u_int dots;
int trailing_dot, ret, saved_herrno;
- int got_nodata = 0, got_servfail = 0, tried_as_is = 0;
+ int got_nodata = 0, got_servfail = 0, root_on_list = 0;
+ int tried_as_is = 0;
+ int searched = 0;
if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
h_errno = NETDB_INTERNAL;
@@ -218,13 +220,14 @@ res_search(name, class, type, answer, an
return (res_query(cp, class, type, answer, anslen));
/*
- * If there are dots in the name already, let's just give it a try
- * 'as is'. The threshold can be set with the "ndots" option.
+ * If there are enough dots in the name, let's just give it a
+ * try 'as is'. The threshold can be set with the "ndots" option.
+ * Also, query 'as is', if there is a trailing dot in the name.
*/
saved_herrno = -1;
- if (dots >= _res.ndots) {
+ if (dots >= _res.ndots || trailing_dot) {
ret = res_querydomain(name, NULL, class, type, answer, anslen);
- if (ret > 0)
+ if (ret > 0 || trailing_dot)
return (ret);
saved_herrno = h_errno;
tried_as_is++;
@@ -243,6 +246,14 @@ res_search(name, class, type, answer, an
for (domain = (const char * const *)_res.dnsrch;
*domain && !done;
domain++) {
+ searched = 1;
+
+ if (domain[0][0] == '\0' ||
+ (domain[0][0] == '.' && domain[0][1] == '\0'))
+ root_on_list++;
+
+ if (root_on_list && tried_as_is)
+ continue;
ret = res_querydomain(name, *domain, class, type,
answer, anslen);
@@ -308,11 +319,11 @@ res_search(name, class, type, answer, an
}
/*
- * If we have not already tried the name "as is", do that now.
- * note that we do this regardless of how many dots were in the
- * name or whether it ends with a dot unless NOTLDQUERY is set.
+ * If the query has not already been tried as is then try it
+ * unless RES_NOTLDQUERY is set and there were no dots.
*/
- if (!tried_as_is && (dots || !(_res.options & RES_NOTLDQUERY))) {
+ if ((dots || !searched || !(_res.options & RES_NOTLDQUERY)) &&
+ !(tried_as_is || root_on_list)) {
ret = res_querydomain(name, NULL, class, type, answer, anslen);
if (ret > 0)
return (ret);
Sincerely,
--
Hajimu UMEMOTO @ Internet Mutual Aid Society Yokohama, Japan
ume@mahoroba.org ume@{,jp.}FreeBSD.org
http://www.imasy.org/~ume/
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