Add support for timeout: and attempts: resolver options.

Submitted by:	Paul Vixie <paul@vix.com> / ISC
MFC After:	1 week

3 files changed, 37 insertions, 1 deletions

diff --git a/include/resolv.h b/include/resolv.h
index 12d14b4..9305023 100644
--- a/include/resolv.h
+++ b/include/resolv.h
@@ -94,6 +94,8 @@
 #define	RES_TIMEOUT		5	/* min. seconds between retries */
 #define	MAXRESOLVSORT		10	/* number of net to sort on */
 #define	RES_MAXNDOTS		15	/* should reflect bit field size */
+#define	RES_MAXRETRANS		30	/* only for resolv.conf/RES_OPTIONS */
+#define	RES_MAXRETRY		5	/* only for resolv.conf/RES_OPTIONS */
 
 struct __res_state {
 	int	retrans;	 	/* retransmition time interval */
diff --git a/lib/libc/net/res_init.c b/lib/libc/net/res_init.c
index 9bb8452..6c22973 100644
--- a/lib/libc/net/res_init.c
+++ b/lib/libc/net/res_init.c
@@ -524,6 +524,26 @@ res_setoptions(options, source)
 			if (_res.options & RES_DEBUG)
 				printf(";;\tndots=%d\n", _res.ndots);
 #endif
+		} else if (!strncmp(cp, "timeout:", sizeof("timeout:") - 1)) {
+			i = atoi(cp + sizeof("timeout:") - 1);
+			if (i <= RES_MAXRETRANS)
+				_res.retrans = i;
+			else
+				_res.retrans = RES_MAXRETRANS;
+#ifdef DEBUG
+			if (_res.options & RES_DEBUG)
+				printf(";;\ttimeout=%d\n", _res.retrans);
+#endif
+		} else if (!strncmp(cp, "attempts:", sizeof("attempts:") - 1)){
+			i = atoi(cp + sizeof("attempts:") - 1);
+			if (i <= RES_MAXRETRY)
+				_res.retry = i;
+			else
+				_res.retry = RES_MAXRETRY;
+#ifdef DEBUG
+			if (_res.options & RES_DEBUG)
+				printf(";;\tretry=%d\n", _res.retry);
+#endif
 		} else if (!strncmp(cp, "debug", sizeof("debug") - 1)) {
 #ifdef DEBUG
 			if (!(_res.options & RES_DEBUG)) {
diff --git a/share/man/man5/resolver.5 b/share/man/man5/resolver.5
index 16320af..535b54e 100644
--- a/share/man/man5/resolver.5
+++ b/share/man/man5/resolver.5
@@ -130,7 +130,7 @@ is one of the following:
 sets
 .Dv RES_DEBUG
 in _res.options.
-.It Sy ndots:n
+.It Sy ndots: Ns Ar n
 sets a threshold for the number of dots which must appear in a name given to
 .Fn res_query
 (see
@@ -146,6 +146,20 @@ meaning that if there are any dots in a name, the name
 will be tried first as an absolute name before any
 .Em search list
 elements are appended to it.
+.It Sy timeout: Ns Ar n
+sets the amount of time the resolver will wait for a response from a remote
+name server before retrying the query via a different name server.  Measured in
+seconds, the default is
+.Dv RES_TIMEOUT
+(see
+.Pa <resolv.h> ) .
+.It Sy attempts: Ns Ar n
+sets the number of times the resolver will send a query to its name servers
+before giving up and returning an error to the calling application.  The
+default is
+.Dv RES_DFLRETRY
+(see
+.Pa <resolv.h> ) .
 .It Sy no_tld_query
 tells the resolver not to attempt to resolve a top level domain name, that
 is, a name that contains no dots.  Use of this option doesn't prevent