From: Jeremy Allison <jra@samba.org>
Date: Thu, 23 Jul 2020 20:10:12 +0000 (-0700)
Subject: s3: Parameters. Add 'async dns timeout' parameter. Default to 10. Minimum value 1.
X-Git-Tag: talloc-2.3.2~896
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8a140391d6d2bba65275bdc7a85a33cc502dbfb7;p=thirdparty%2Fsamba.git

s3: Parameters. Add 'async dns timeout' parameter. Default to 10. Minimum value 1.

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>
---

diff --git a/docs-xml/smbdotconf/tuning/asyncdnstimeout.xml b/docs-xml/smbdotconf/tuning/asyncdnstimeout.xml
new file mode 100644
index 00000000000..6c7ead2b2fd
--- /dev/null
+++ b/docs-xml/smbdotconf/tuning/asyncdnstimeout.xml
@@ -0,0 +1,21 @@
+<samba:parameter name="async dns timeout"
+                 context="G"
+                 type="integer"
+                 xmlns:samba="http://www.samba.org/samba/DTD/samba-doc">
+<description>
+    <para>The number of seconds the asynchronous DNS
+    resolver code in Samba will wait for responses.
+    Some of the Samba client library code uses internal
+    asynchronous DNS resolution for A and AAAA records
+    when trying to find Active Directory Domain controllers.
+    This value prevents this name resolution code from
+    waiting for DNS server timeouts.
+    </para>
+    <para>The minimum value of this parameter is clamped
+    at 1 second.
+    zero.</para>
+</description>
+
+<value type="default">10</value>
+<value type="example">20</value>
+</samba:parameter>
diff --git a/lib/param/loadparm.c b/lib/param/loadparm.c
index dc22f646b3e..7e9767590f9 100644
--- a/lib/param/loadparm.c
+++ b/lib/param/loadparm.c
@@ -3066,6 +3066,9 @@ struct loadparm_context *loadparm_init(TALLOC_CTX *mem_ctx)
 	lpcfg_do_global_parameter(
 		lp_ctx, "ldap max search request size", "256000");
 
+	/* Async DNS query timeout in seconds. */
+	lpcfg_do_global_parameter(lp_ctx, "async dns timeout", "10");
+
 	for (i = 0; parm_table[i].label; i++) {
 		if (!(lp_ctx->flags[i] & FLAG_CMDLINE)) {
 			lp_ctx->flags[i] |= FLAG_DEFAULT;
diff --git a/source3/include/proto.h b/source3/include/proto.h
index d349e22aa6b..51bac188919 100644
--- a/source3/include/proto.h
+++ b/source3/include/proto.h
@@ -886,6 +886,7 @@ int lp_min_receive_file_size(void);
 void widelinks_warning(int snum);
 const char *lp_ncalrpc_dir(void);
 void _lp_set_server_role(int server_role);
+uint32_t lp_get_async_dns_timeout(void);
 
 /* The following definitions come from param/loadparm_ctx.c  */
 
diff --git a/source3/param/loadparm.c b/source3/param/loadparm.c
index cf5da0aca21..ebe120433ee 100644
--- a/source3/param/loadparm.c
+++ b/source3/param/loadparm.c
@@ -961,6 +961,9 @@ static void init_globals(struct loadparm_context *lp_ctx, bool reinit_globals)
 	Globals.ldap_max_authenticated_request_size = 16777216;
 	Globals.ldap_max_search_request_size = 256000;
 
+	/* Async DNS query timeout (in seconds). */
+	Globals.async_dns_timeout = 10;
+
 	/* Now put back the settings that were set with lp_set_cmdline() */
 	apply_lp_set_cmdline();
 }
@@ -4755,3 +4758,16 @@ enum samba_weak_crypto lp_weak_crypto()
 
 	return Globals.weak_crypto;
 }
+
+uint32_t lp_get_async_dns_timeout(void)
+{
+	uint32_t val = Globals.async_dns_timeout;
+	/*
+	 * Clamp minimum async dns timeout to 1 second
+	 * as per the man page.
+	 */
+	if (val < 1) {
+		val = 1;
+	}
+	return val;
+}