Merge branch '2785-resconf-timeout-retry.conf' into 'main'

Parse timeout and attempts from resolv.conf

Closes #2785

See merge request isc-projects/bind9!5273

CHANGES

@@ -1,3 +1,10 @@
+5693.	[func]		Restore support for reading 'timeout' and 'attempts'
+			options from /etc/resolv.conf, and use their values
+			in dig, host and nslookup. (Previously this was
+			supported by liblwres, and was still mentioned
+			in man pages, but had stopped working after liblwres
+			was deprecated in favor of libirs.) [GL #2785]
+
 5692.	[bug]		Fix a rare crash in the DoH code caused by
 			detaching from an HTTP/2 session handle too early when
 			sending data. [GL #2851]

bin/dig/dighost.c

@@ -114,7 +114,7 @@ isc_sockaddr_t localaddr;
 isc_refcount_t sendcount = ATOMIC_VAR_INIT(0);
 isc_refcount_t recvcount = ATOMIC_VAR_INIT(0);
 int ndots = -1;
-int tries = 3;
+int tries = -1;
 int lookup_counter = 0;
 
 static char servercookie[256];
@@ -1276,6 +1276,17 @@ setup_system(bool ipv4only, bool ipv6only) {
 		ndots = irs_resconf_getndots(resconf);
 		debug("ndots is %d.", ndots);
 	}
+	if (timeout == 0) {
+		timeout = irs_resconf_gettimeout(resconf);
+		debug("timeout is %d.", timeout);
+	}
+	if (tries == -1) {
+		tries = irs_resconf_getattempts(resconf);
+		if (tries == 0) {
+			tries = 3;
+		}
+		debug("retries is %d.", tries);
+	}
 
 	/* If user doesn't specify server use nameservers from resolv.conf. */
 	if (ISC_LIST_EMPTY(server_list)) {

lib/irs/include/irs/resconf.h

@@ -115,4 +115,24 @@ irs_resconf_getndots(irs_resconf_t *conf);
  *\li	'conf' is a valid resconf object.
  */
 
+unsigned int
+irs_resconf_getattempts(irs_resconf_t *conf);
+/*%<
+ * Return the 'attempts' value stored in 'conf'.
+ *
+ * Requires:
+ *
+ *\li	'conf' is a valid resconf object.
+ */
+
+unsigned int
+irs_resconf_gettimeout(irs_resconf_t *conf);
+/*%<
+ * Return the 'timeout' value stored in 'conf'.
+ *
+ * Requires:
+ *
+ *\li	'conf' is a valid resconf object.
+ */
+
 ISC_LANG_ENDDECLS

lib/irs/resconf.c

@@ -74,6 +74,13 @@
 #define RESCONFMAXLINELEN     256U /*%< max size of a line */
 #define RESCONFMAXSORTLIST    10U  /*%< max 10 */
 
+#define CHECK(op)                            \
+	do {                                 \
+		result = (op);               \
+		if (result != ISC_R_SUCCESS) \
+			goto cleanup;        \
+	} while (0)
+
 /*!
  * configuration data structure
  */
@@ -108,6 +115,10 @@ struct irs_resconf {
 	uint8_t resdebug;
 	/*%< set to n in 'options ndots:n' */
 	uint8_t ndots;
+	/*%< set to n in 'options attempts:n' */
+	uint8_t attempts;
+	/*%< set to n in 'options timeout:n' */
+	uint8_t timeout;
 };
 
 static isc_result_t
@@ -165,8 +176,8 @@ eatwhite(FILE *fp) {
  */
 static int
 getword(FILE *fp, char *buffer, size_t size) {
+	char *p = NULL;
 	int ch;
-	char *p;
 
 	REQUIRE(buffer != NULL);
 	REQUIRE(size > 0U);
@@ -446,11 +457,26 @@ resconf_parsesortlist(irs_resconf_t *conf, FILE *fp) {
 	return (ISC_R_SUCCESS);
 }
 
+static isc_result_t
+resconf_optionnumber(const char *word, uint8_t *number) {
+	char *p;
+	long n;
+
+	n = strtol(word, &p, 10);
+	if (*p != '\0') { /* Bad string. */
+		return (ISC_R_UNEXPECTEDTOKEN);
+	}
+	if (n < 0 || n > 0xff) { /* Out of range. */
+		return (ISC_R_RANGE);
+	}
+	*number = n;
+	return (ISC_R_SUCCESS);
+}
+
 static isc_result_t
 resconf_parseoption(irs_resconf_t *conf, FILE *fp) {
 	int delim;
-	long ndots;
-	char *p;
+	isc_result_t result = ISC_R_SUCCESS;
 	char word[RESCONFMAXLINELEN];
 
 	delim = getword(fp, word, sizeof(word));
@@ -462,14 +488,11 @@ resconf_parseoption(irs_resconf_t *conf, FILE *fp) {
 		if (strcmp("debug", word) == 0) {
 			conf->resdebug = 1;
 		} else if (strncmp("ndots:", word, 6) == 0) {
-			ndots = strtol(word + 6, &p, 10);
-			if (*p != '\0') { /* Bad string. */
-				return (ISC_R_UNEXPECTEDTOKEN);
-			}
-			if (ndots < 0 || ndots > 0xff) { /* Out of range. */
-				return (ISC_R_RANGE);
-			}
-			conf->ndots = (uint8_t)ndots;
+			CHECK(resconf_optionnumber(word + 6, &conf->ndots));
+		} else if (strncmp("attempts:", word, 9) == 0) {
+			CHECK(resconf_optionnumber(word + 9, &conf->attempts));
+		} else if (strncmp("timeout:", word, 8) == 0) {
+			CHECK(resconf_optionnumber(word + 8, &conf->timeout));
 		}
 
 		if (delim == EOF || delim == '\n') {
@@ -479,7 +502,8 @@ resconf_parseoption(irs_resconf_t *conf, FILE *fp) {
 		}
 	}
 
-	return (ISC_R_SUCCESS);
+cleanup:
+	return (result);
 }
 
 static isc_result_t
@@ -521,6 +545,8 @@ irs_resconf_load(isc_mem_t *mctx, const char *filename, irs_resconf_t **confp) {
 	conf->sortlistnxt = 0;
 	conf->resdebug = 0;
 	conf->ndots = 1;
+	conf->attempts = 3;
+	conf->timeout = 0;
 	for (i = 0; i < RESCONFMAXSEARCH; i++) {
 		conf->search[i] = NULL;
 	}
@@ -669,3 +695,17 @@ irs_resconf_getndots(irs_resconf_t *conf) {
 
 	return ((unsigned int)conf->ndots);
 }
+
+unsigned int
+irs_resconf_getattempts(irs_resconf_t *conf) {
+	REQUIRE(IRS_RESCONF_VALID(conf));
+
+	return ((unsigned int)conf->attempts);
+}
+
+unsigned int
+irs_resconf_gettimeout(irs_resconf_t *conf) {
+	REQUIRE(IRS_RESCONF_VALID(conf));
+
+	return ((unsigned int)conf->timeout);
+}

lib/irs/tests/resconf_test.c

@@ -42,6 +42,43 @@ setup_test(void) {
 	assert_return_code(chdir(TESTS_DIR), 0);
 }
 
+static isc_result_t
+check_number(unsigned int n, unsigned int expected) {
+	return ((n == expected) ? ISC_R_SUCCESS : ISC_R_BADNUMBER);
+}
+
+static isc_result_t
+check_attempts(irs_resconf_t *resconf) {
+	return (check_number(irs_resconf_getattempts(resconf), 4));
+}
+
+static isc_result_t
+check_timeout(irs_resconf_t *resconf) {
+	return (check_number(irs_resconf_gettimeout(resconf), 1));
+}
+
+static isc_result_t
+check_ndots(irs_resconf_t *resconf) {
+	return (check_number(irs_resconf_getndots(resconf), 2));
+}
+
+static isc_result_t
+check_options(irs_resconf_t *resconf) {
+	if (irs_resconf_getattempts(resconf) != 3) {
+		return ISC_R_BADNUMBER; /* default value only */
+	}
+
+	if (irs_resconf_getndots(resconf) != 2) {
+		return ISC_R_BADNUMBER;
+	}
+
+	if (irs_resconf_gettimeout(resconf) != 1) {
+		return ISC_R_BADNUMBER;
+	}
+
+	return (ISC_R_SUCCESS);
+}
+
 /* test irs_resconf_load() */
 static void
 irs_resconf_load_test(void **state) {
@@ -61,15 +98,18 @@ irs_resconf_load_test(void **state) {
 		  ISC_R_SUCCESS },
 		{ "testdata/nameserver-v6-scoped.conf", ISC_R_SUCCESS, NULL,
 		  ISC_R_SUCCESS },
+		{ "testdata/options-attempts.conf", ISC_R_SUCCESS,
+		  check_attempts, ISC_R_SUCCESS },
 		{ "testdata/options-debug.conf", ISC_R_SUCCESS, NULL,
 		  ISC_R_SUCCESS },
-		{ "testdata/options-ndots.conf", ISC_R_SUCCESS, NULL,
+		{ "testdata/options-ndots.conf", ISC_R_SUCCESS, check_ndots,
 		  ISC_R_SUCCESS },
-		{ "testdata/options-timeout.conf", ISC_R_SUCCESS, NULL,
+		{ "testdata/options-timeout.conf", ISC_R_SUCCESS, check_timeout,
 		  ISC_R_SUCCESS },
 		{ "testdata/options-unknown.conf", ISC_R_SUCCESS, NULL,
 		  ISC_R_SUCCESS },
-		{ "testdata/options.conf", ISC_R_SUCCESS, NULL, ISC_R_SUCCESS },
+		{ "testdata/options.conf", ISC_R_SUCCESS, check_options,
+		  ISC_R_SUCCESS },
 		{ "testdata/options-bad-ndots.conf", ISC_R_RANGE, NULL,
 		  ISC_R_SUCCESS },
 		{ "testdata/options-empty.conf", ISC_R_UNEXPECTEDEND, NULL,

lib/irs/tests/testdata/options-attempts.conf

@@ -0,0 +1,10 @@
+# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, you can obtain one at https://mozilla.org/MPL/2.0/.
+#
+# See the COPYRIGHT file distributed with this work for additional
+# information regarding copyright ownership.
+
+options attempts:4

lib/irs/tests/testdata/options-ndots.conf

@@ -7,4 +7,4 @@
 # See the COPYRIGHT file distributed with this work for additional
 # information regarding copyright ownership.
 
-option ndots:2
+options ndots:2