Adding upstream version 1:9.11.5.P4+dfsg.upstream/1%9.11.5.P4+dfsgupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1216 insertions, 0 deletions

diff --git a/lib/samples/nsprobe.c b/lib/samples/nsprobe.c
new file mode 100644
index 0000000..2ebb19a
--- /dev/null
+++ b/lib/samples/nsprobe.c
@@ -0,0 +1,1216 @@
+/*
+ * 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 http://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+
+#include <config.h>
+
+#ifndef WIN32
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include <unistd.h>
+#include <netdb.h>
+#endif
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <isc/app.h>
+#include <isc/buffer.h>
+#include <isc/commandline.h>
+#include <isc/lib.h>
+#include <isc/mem.h>
+#include <isc/print.h>
+#include <isc/socket.h>
+#include <isc/sockaddr.h>
+#include <isc/string.h>
+#include <isc/task.h>
+#include <isc/timer.h>
+#include <isc/util.h>
+
+#include <dns/client.h>
+#include <dns/fixedname.h>
+#include <dns/lib.h>
+#include <dns/message.h>
+#include <dns/name.h>
+#include <dns/rdata.h>
+#include <dns/rdataset.h>
+#include <dns/rdatastruct.h>
+#include <dns/rdatatype.h>
+#include <dns/result.h>
+
+#define MAX_PROBES 1000
+
+static dns_client_t *client = NULL;
+static isc_task_t *probe_task = NULL;
+static isc_appctx_t *actx = NULL;
+static isc_mem_t *mctx = NULL;
+static unsigned int outstanding_probes = 0;
+const char *cacheserver = "127.0.0.1";
+static FILE *input;
+
+typedef enum {
+	none,
+	exist,
+	nxdomain,
+	othererr,
+	multiplesoa,
+	multiplecname,
+	brokenanswer,
+	lame,
+	timedout,
+	notype,
+	unexpected
+} query_result_t;
+
+struct server {
+	ISC_LINK(struct server) link;
+
+	isc_sockaddr_t address;
+	query_result_t result_a;
+	query_result_t result_aaaa;
+};
+
+struct probe_ns {
+	ISC_LINK(struct probe_ns) link;
+
+	dns_fixedname_t fixedname;
+	dns_name_t *name;
+	struct server *current_server;
+	ISC_LIST(struct server) servers;
+};
+
+struct probe_trans {
+	bool inuse;
+	char *domain;
+	dns_fixedname_t fixedname;
+	dns_name_t *qname;
+	const char **qlabel;
+	bool qname_found;
+	dns_clientrestrans_t *resid;
+	dns_message_t *qmessage;
+	dns_message_t *rmessage;
+	dns_clientreqtrans_t *reqid;
+
+	/* NS list */
+	struct probe_ns *current_ns;
+	ISC_LIST(struct probe_ns) nslist;
+};
+
+struct lcl_stat {
+	unsigned long valid;
+	unsigned long ignore;
+	unsigned long nxdomain;
+	unsigned long othererr;
+	unsigned long multiplesoa;
+	unsigned long multiplecname;
+	unsigned long brokenanswer;
+	unsigned long lame;
+	unsigned long unknown;
+} server_stat, domain_stat;
+
+static unsigned long number_of_domains = 0;
+static unsigned long number_of_servers = 0;
+static unsigned long multiple_error_domains = 0;
+static bool debug_mode = false;
+static int verbose_level = 0;
+static const char *qlabels[] = {"www.", "ftp.", NULL};
+static struct probe_trans probes[MAX_PROBES];
+
+static isc_result_t probe_domain(struct probe_trans *trans);
+static void reset_probe(struct probe_trans *trans);
+static isc_result_t fetch_nsaddress(struct probe_trans *trans);
+static isc_result_t probe_name(struct probe_trans *trans,
+			       dns_rdatatype_t type);
+
+/* Dump an rdataset for debug */
+static isc_result_t
+print_rdataset(dns_rdataset_t *rdataset, dns_name_t *owner) {
+	isc_buffer_t target;
+	isc_result_t result;
+	isc_region_t r;
+	char t[4096];
+
+	if (!debug_mode)
+		return (ISC_R_SUCCESS);
+
+	isc_buffer_init(&target, t, sizeof(t));
+
+	if (!dns_rdataset_isassociated(rdataset))
+		return (ISC_R_SUCCESS);
+	result = dns_rdataset_totext(rdataset, owner, false, false,
+				     &target);
+	if (result != ISC_R_SUCCESS)
+		return (result);
+	isc_buffer_usedregion(&target, &r);
+	printf("%.*s", (int)r.length, (char *)r.base);
+
+	return (ISC_R_SUCCESS);
+}
+
+static isc_result_t
+print_name(dns_name_t *name) {
+	isc_result_t result;
+	isc_buffer_t target;
+	isc_region_t r;
+	char t[4096];
+
+	isc_buffer_init(&target, t, sizeof(t));
+	result = dns_name_totext(name, true, &target);
+	if (result == ISC_R_SUCCESS) {
+		isc_buffer_usedregion(&target, &r);
+		printf("%.*s", (int)r.length, (char *)r.base);
+	} else
+		printf("(invalid name)");
+
+	return (result);
+}
+
+static isc_result_t
+print_address(FILE *fp, isc_sockaddr_t *addr) {
+	char buf[NI_MAXHOST];
+
+	if (getnameinfo(&addr->type.sa, addr->length, buf, sizeof(buf),
+			NULL, 0, NI_NUMERICHOST) == 0) {
+		fprintf(fp, "%s", buf);
+	} else {
+		fprintf(fp, "(invalid address)");
+	}
+
+	return (ISC_R_SUCCESS);
+}
+
+static void
+ctxs_destroy(isc_mem_t **mctxp, isc_appctx_t **actxp,
+	     isc_taskmgr_t **taskmgrp, isc_socketmgr_t **socketmgrp,
+	     isc_timermgr_t **timermgrp)
+{
+	if (*taskmgrp != NULL)
+		isc_taskmgr_destroy(taskmgrp);
+
+	if (*timermgrp != NULL)
+		isc_timermgr_destroy(timermgrp);
+
+	if (*socketmgrp != NULL)
+		isc_socketmgr_destroy(socketmgrp);
+
+	if (*actxp != NULL)
+		isc_appctx_destroy(actxp);
+
+	if (*mctxp != NULL)
+		isc_mem_destroy(mctxp);
+}
+
+static isc_result_t
+ctxs_init(isc_mem_t **mctxp, isc_appctx_t **actxp,
+	  isc_taskmgr_t **taskmgrp, isc_socketmgr_t **socketmgrp,
+	  isc_timermgr_t **timermgrp)
+{
+	isc_result_t result;
+
+	result = isc_mem_create(0, 0, mctxp);
+	if (result != ISC_R_SUCCESS)
+		goto fail;
+
+	result = isc_appctx_create(*mctxp, actxp);
+	if (result != ISC_R_SUCCESS)
+		goto fail;
+
+	result = isc_taskmgr_createinctx(*mctxp, *actxp, 1, 0, taskmgrp);
+	if (result != ISC_R_SUCCESS)
+		goto fail;
+
+	result = isc_socketmgr_createinctx(*mctxp, *actxp, socketmgrp);
+	if (result != ISC_R_SUCCESS)
+		goto fail;
+
+	result = isc_timermgr_createinctx(*mctxp, *actxp, timermgrp);
+	if (result != ISC_R_SUCCESS)
+		goto fail;
+
+	return (ISC_R_SUCCESS);
+
+ fail:
+	ctxs_destroy(mctxp, actxp, taskmgrp, socketmgrp, timermgrp);
+
+	return (result);
+}
+
+/*
+ * Common routine to make query data
+ */
+static isc_result_t
+make_querymessage(dns_message_t *message, dns_name_t *qname0,
+		  dns_rdatatype_t rdtype)
+{
+	dns_name_t *qname = NULL;
+	dns_rdataset_t *qrdataset = NULL;
+	isc_result_t result;
+
+	message->opcode = dns_opcode_query;
+	message->rdclass = dns_rdataclass_in;
+
+	result = dns_message_gettempname(message, &qname);
+	if (result != ISC_R_SUCCESS)
+		goto cleanup;
+
+	result = dns_message_gettemprdataset(message, &qrdataset);
+	if (result != ISC_R_SUCCESS)
+		goto cleanup;
+
+	dns_name_init(qname, NULL);
+	dns_name_clone(qname0, qname);
+	dns_rdataset_makequestion(qrdataset, message->rdclass, rdtype);
+	ISC_LIST_APPEND(qname->list, qrdataset, link);
+	dns_message_addname(message, qname, DNS_SECTION_QUESTION);
+
+	return (ISC_R_SUCCESS);
+
+ cleanup:
+	if (qname != NULL)
+		dns_message_puttempname(message, &qname);
+	if (qrdataset != NULL)
+		dns_message_puttemprdataset(message, &qrdataset);
+	return (result);
+}
+
+/*
+ * Update statistics
+ */
+static inline void
+increment_entry(unsigned long *entryp) {
+	(*entryp)++;
+	INSIST(*entryp != 0U);	/* check overflow */
+}
+
+static void
+update_stat(struct probe_trans *trans) {
+	struct probe_ns *pns;
+	struct server *server;
+	struct lcl_stat local_stat;
+	unsigned int err_count = 0;
+	const char *stattype;
+
+	increment_entry(&number_of_domains);
+	memset(&local_stat, 0, sizeof(local_stat));
+
+	/* Update per sever statistics */
+	for (pns = ISC_LIST_HEAD(trans->nslist); pns != NULL;
+	     pns = ISC_LIST_NEXT(pns, link)) {
+		for (server = ISC_LIST_HEAD(pns->servers); server != NULL;
+		     server = ISC_LIST_NEXT(server, link)) {
+			increment_entry(&number_of_servers);
+
+			if (server->result_aaaa == exist ||
+			    server->result_aaaa == notype) {
+				/*
+				 * Don't care about the result of A query if
+				 * the answer to AAAA query was expected.
+				 */
+				stattype = "valid";
+				increment_entry(&server_stat.valid);
+				increment_entry(&local_stat.valid);
+			} else if (server->result_a == exist) {
+				switch (server->result_aaaa) {
+				case exist:
+				case notype:
+					stattype = "valid";
+					increment_entry(&server_stat.valid);
+					increment_entry(&local_stat.valid);
+					break;
+				case timedout:
+					stattype = "ignore";
+					increment_entry(&server_stat.ignore);
+					increment_entry(&local_stat.ignore);
+					break;
+				case nxdomain:
+					stattype = "nxdomain";
+					increment_entry(&server_stat.nxdomain);
+					increment_entry(&local_stat.nxdomain);
+					break;
+				case othererr:
+					stattype = "othererr";
+					increment_entry(&server_stat.othererr);
+					increment_entry(&local_stat.othererr);
+					break;
+				case multiplesoa:
+					stattype = "multiplesoa";
+					increment_entry(&server_stat.multiplesoa);
+					increment_entry(&local_stat.multiplesoa);
+					break;
+				case multiplecname:
+					stattype = "multiplecname";
+					increment_entry(&server_stat.multiplecname);
+					increment_entry(&local_stat.multiplecname);
+					break;
+				case brokenanswer:
+					stattype = "brokenanswer";
+					increment_entry(&server_stat.brokenanswer);
+					increment_entry(&local_stat.brokenanswer);
+					break;
+				case lame:
+					stattype = "lame";
+					increment_entry(&server_stat.lame);
+					increment_entry(&local_stat.lame);
+					break;
+				default:
+					stattype = "unknown";
+					increment_entry(&server_stat.unknown);
+					increment_entry(&local_stat.unknown);
+					break;
+				}
+			} else {
+				stattype = "unknown";
+				increment_entry(&server_stat.unknown);
+				increment_entry(&local_stat.unknown);
+			}
+
+			if (verbose_level > 1 ||
+			    (verbose_level == 1 &&
+			     strcmp(stattype, "valid") != 0 &&
+			     strcmp(stattype, "unknown") != 0)) {
+				print_name(pns->name);
+				putchar('(');
+				print_address(stdout, &server->address);
+				printf(") for %s:%s\n", trans->domain,
+				       stattype);
+			}
+		}
+	}
+
+	/* Update per domain statistics */
+	if (local_stat.ignore > 0U) {
+		if (verbose_level > 0)
+			printf("%s:ignore\n", trans->domain);
+		increment_entry(&domain_stat.ignore);
+		err_count++;
+	}
+	if (local_stat.nxdomain > 0U) {
+		if (verbose_level > 0)
+			printf("%s:nxdomain\n", trans->domain);
+		increment_entry(&domain_stat.nxdomain);
+		err_count++;
+	}
+	if (local_stat.othererr > 0U) {
+		if (verbose_level > 0)
+			printf("%s:othererr\n", trans->domain);
+		increment_entry(&domain_stat.othererr);
+		err_count++;
+	}
+	if (local_stat.multiplesoa > 0U) {
+		if (verbose_level > 0)
+			printf("%s:multiplesoa\n", trans->domain);
+		increment_entry(&domain_stat.multiplesoa);
+		err_count++;
+	}
+	if (local_stat.multiplecname > 0U) {
+		if (verbose_level > 0)
+			printf("%s:multiplecname\n", trans->domain);
+		increment_entry(&domain_stat.multiplecname);
+		err_count++;
+	}
+	if (local_stat.brokenanswer > 0U) {
+		if (verbose_level > 0)
+			printf("%s:brokenanswer\n", trans->domain);
+		increment_entry(&domain_stat.brokenanswer);
+		err_count++;
+	}
+	if (local_stat.lame > 0U) {
+		if (verbose_level > 0)
+			printf("%s:lame\n", trans->domain);
+		increment_entry(&domain_stat.lame);
+		err_count++;
+	}
+
+	if (err_count > 1U)
+		increment_entry(&multiple_error_domains);
+
+	/*
+	 * We regard the domain as valid if and only if no authoritative server
+	 * has a problem and at least one server is known to be valid.
+	 */
+	if (local_stat.valid > 0U && err_count == 0U) {
+		if (verbose_level > 1)
+			printf("%s:valid\n", trans->domain);
+		increment_entry(&domain_stat.valid);
+	}
+
+	/*
+	 * If the domain has no available server or all servers have the
+	 * 'unknown' result, the domain's result is also regarded as unknown.
+	 */
+	if (local_stat.valid == 0U && err_count == 0U) {
+		if (verbose_level > 1)
+			printf("%s:unknown\n", trans->domain);
+		increment_entry(&domain_stat.unknown);
+	}
+}
+
+/*
+ * Search for an existent name with an A RR
+ */
+
+static isc_result_t
+set_nextqname(struct probe_trans *trans) {
+	isc_result_t result;
+	unsigned int domainlen;
+	isc_buffer_t b;
+	char buf[4096];	/* XXX ad-hoc constant, but should be enough */
+
+	if (*trans->qlabel == NULL)
+		return (ISC_R_NOMORE);
+
+	result = isc_string_copy(buf, sizeof(buf), *trans->qlabel);
+	if (result != ISC_R_SUCCESS)
+		return (result);
+	result = isc_string_append(buf, sizeof(buf), trans->domain);
+	if (result != ISC_R_SUCCESS)
+		return (result);
+
+	domainlen = strlen(buf);
+	isc_buffer_init(&b, buf, domainlen);
+	isc_buffer_add(&b, domainlen);
+	trans->qname = dns_fixedname_initname(&trans->fixedname);
+	result = dns_name_fromtext(trans->qname, &b, dns_rootname,
+				   0, NULL);
+
+	trans->qlabel++;
+
+	return (result);
+}
+
+static void
+request_done(isc_task_t *task, isc_event_t *event) {
+	struct probe_trans *trans = event->ev_arg;
+	dns_clientreqevent_t *rev = (dns_clientreqevent_t *)event;
+	dns_message_t *rmessage;
+	struct probe_ns *pns;
+	struct server *server;
+	isc_result_t result;
+	query_result_t *resultp;
+	dns_name_t *name;
+	dns_rdataset_t *rdataset;
+	dns_rdatatype_t type;
+
+	REQUIRE(task == probe_task);
+	REQUIRE(trans != NULL && trans->inuse == true);
+	rmessage = rev->rmessage;
+	REQUIRE(rmessage == trans->rmessage);
+	INSIST(outstanding_probes > 0);
+
+	server = trans->current_ns->current_server;
+	INSIST(server != NULL);
+
+	if (server->result_a == none) {
+		type = dns_rdatatype_a;
+		resultp = &server->result_a;
+	} else {
+		resultp = &server->result_aaaa;
+		type = dns_rdatatype_aaaa;
+	}
+
+	if (rev->result == ISC_R_SUCCESS) {
+		if ((rmessage->flags & DNS_MESSAGEFLAG_AA) == 0)
+			*resultp = lame;
+		else if (rmessage->rcode == dns_rcode_nxdomain)
+			*resultp = nxdomain;
+		else if (rmessage->rcode != dns_rcode_noerror)
+			*resultp = othererr;
+		else if (rmessage->counts[DNS_SECTION_ANSWER] == 0) {
+			/* no error but empty answer */
+			*resultp = notype;
+		} else {
+			result = dns_message_firstname(rmessage,
+						       DNS_SECTION_ANSWER);
+			while (result == ISC_R_SUCCESS) {
+				name = NULL;
+				dns_message_currentname(rmessage,
+							DNS_SECTION_ANSWER,
+							&name);
+				for (rdataset = ISC_LIST_HEAD(name->list);
+				     rdataset != NULL;
+				     rdataset = ISC_LIST_NEXT(rdataset,
+							      link)) {
+					(void)print_rdataset(rdataset, name);
+
+					if (rdataset->type ==
+					    dns_rdatatype_cname ||
+					    rdataset->type ==
+					    dns_rdatatype_dname) {
+						/* Should chase the chain? */
+						*resultp = exist;
+						goto found;
+					} else if (rdataset->type == type) {
+						*resultp = exist;
+						goto found;
+					}
+				}
+				result = dns_message_nextname(rmessage,
+							      DNS_SECTION_ANSWER);
+			}
+
+			/*
+			 * Something unexpected happened: the response
+			 * contained a non-empty authoritative answer, but we
+			 * could not find an expected result.
+			 */
+			*resultp = unexpected;
+		}
+	} else if (rev->result == DNS_R_RECOVERABLE ||
+		   rev->result == DNS_R_BADLABELTYPE) {
+		/* Broken response.  Try identifying known cases. */
+		*resultp = brokenanswer;
+
+		if (rmessage->counts[DNS_SECTION_ANSWER] > 0) {
+			result = dns_message_firstname(rmessage,
+						       DNS_SECTION_ANSWER);
+			while (result == ISC_R_SUCCESS) {
+				/*
+				 * Check to see if the response has multiple
+				 * CNAME RRs.  Update the result code if so.
+				 */
+				name = NULL;
+				dns_message_currentname(rmessage,
+							DNS_SECTION_ANSWER,
+							&name);
+				for (rdataset = ISC_LIST_HEAD(name->list);
+				     rdataset != NULL;
+				     rdataset = ISC_LIST_NEXT(rdataset,
+							      link)) {
+					if (rdataset->type ==
+					    dns_rdatatype_cname &&
+					    dns_rdataset_count(rdataset) > 1) {
+						*resultp = multiplecname;
+						goto found;
+					}
+				}
+				result = dns_message_nextname(rmessage,
+							      DNS_SECTION_ANSWER);
+			}
+		}
+
+		if (rmessage->counts[DNS_SECTION_AUTHORITY] > 0) {
+			result = dns_message_firstname(rmessage,
+						       DNS_SECTION_AUTHORITY);
+			while (result == ISC_R_SUCCESS) {
+				/*
+				 * Check to see if the response has multiple
+				 * SOA RRs.  Update the result code if so.
+				 */
+				name = NULL;
+				dns_message_currentname(rmessage,
+							DNS_SECTION_AUTHORITY,
+							&name);
+				for (rdataset = ISC_LIST_HEAD(name->list);
+				     rdataset != NULL;
+				     rdataset = ISC_LIST_NEXT(rdataset,
+							      link)) {
+					if (rdataset->type ==
+					    dns_rdatatype_soa &&
+					    dns_rdataset_count(rdataset) > 1) {
+						*resultp = multiplesoa;
+						goto found;
+					}
+				}
+				result = dns_message_nextname(rmessage,
+							      DNS_SECTION_AUTHORITY);
+			}
+		}
+	} else if (rev->result == ISC_R_TIMEDOUT)
+		*resultp = timedout;
+	else {
+		fprintf(stderr, "unexpected result: %u (domain=%s, server=",
+			rev->result, trans->domain);
+		print_address(stderr, &server->address);
+		fputc('\n', stderr);
+		*resultp = unexpected;
+	}
+
+ found:
+	INSIST(*resultp != none);
+	if (type == dns_rdatatype_a && *resultp == exist)
+		trans->qname_found = true;
+
+	dns_client_destroyreqtrans(&trans->reqid);
+	isc_event_free(&event);
+	dns_message_reset(trans->rmessage, DNS_MESSAGE_INTENTPARSE);
+
+	result = probe_name(trans, type);
+	if (result == ISC_R_NOMORE) {
+		/* We've tried all addresses of all servers. */
+		if (type == dns_rdatatype_a && trans->qname_found) {
+			/*
+			 * If we've explored A RRs and found an existent
+			 * record, we can move to AAAA.
+			 */
+			trans->current_ns = ISC_LIST_HEAD(trans->nslist);
+			probe_name(trans, dns_rdatatype_aaaa);
+			result = ISC_R_SUCCESS;
+		} else if (type == dns_rdatatype_a) {
+			/*
+			 * No server provided an existent A RR of this name.
+			 * Try next label.
+			 */
+			dns_fixedname_invalidate(&trans->fixedname);
+			trans->qname = NULL;
+			result = set_nextqname(trans);
+			if (result == ISC_R_SUCCESS) {
+				trans->current_ns =
+					ISC_LIST_HEAD(trans->nslist);
+				for (pns = trans->current_ns; pns != NULL;
+				     pns = ISC_LIST_NEXT(pns, link)) {
+					for (server = ISC_LIST_HEAD(pns->servers);
+					     server != NULL;
+					     server = ISC_LIST_NEXT(server,
+								    link)) {
+						INSIST(server->result_aaaa ==
+						       none);
+						server->result_a = none;
+					}
+				}
+				result = probe_name(trans, dns_rdatatype_a);
+			}
+		}
+		if (result != ISC_R_SUCCESS) {
+			/*
+			 * We've explored AAAA RRs or failed to find a valid
+			 * query label.  Wrap up the result and move to the
+			 * next domain.
+			 */
+			reset_probe(trans);
+		}
+	} else if (result != ISC_R_SUCCESS)
+		reset_probe(trans); /* XXX */
+}
+
+static isc_result_t
+probe_name(struct probe_trans *trans, dns_rdatatype_t type) {
+	isc_result_t result;
+	struct probe_ns *pns;
+	struct server *server;
+
+	REQUIRE(trans->reqid == NULL);
+	REQUIRE(type == dns_rdatatype_a || type == dns_rdatatype_aaaa);
+
+	for (pns = trans->current_ns; pns != NULL;
+	     pns = ISC_LIST_NEXT(pns, link)) {
+		for (server = ISC_LIST_HEAD(pns->servers); server != NULL;
+		     server = ISC_LIST_NEXT(server, link)) {
+			if ((type == dns_rdatatype_a &&
+			     server->result_a == none) ||
+			    (type == dns_rdatatype_aaaa &&
+			     server->result_aaaa == none)) {
+				pns->current_server = server;
+				goto found;
+			}
+		}
+	}
+
+ found:
+	trans->current_ns = pns;
+	if (pns == NULL)
+		return (ISC_R_NOMORE);
+
+	INSIST(pns->current_server != NULL);
+	dns_message_reset(trans->qmessage, DNS_MESSAGE_INTENTRENDER);
+	result = make_querymessage(trans->qmessage, trans->qname, type);
+	if (result != ISC_R_SUCCESS)
+		return (result);
+	result = dns_client_startrequest(client, trans->qmessage,
+					 trans->rmessage,
+					 &pns->current_server->address,
+					 0, DNS_MESSAGEPARSE_BESTEFFORT,
+					 NULL, 120, 0, 4,
+					 probe_task, request_done, trans,
+					 &trans->reqid);
+
+	return (result);
+}
+
+/*
+ * Get IP addresses of NSes
+ */
+
+static void
+resolve_nsaddress(isc_task_t *task, isc_event_t *event) {
+	struct probe_trans *trans = event->ev_arg;
+	dns_clientresevent_t *rev = (dns_clientresevent_t *)event;
+	dns_name_t *name;
+	dns_rdataset_t *rdataset;
+	dns_rdata_t rdata = DNS_RDATA_INIT;
+	struct probe_ns *pns = trans->current_ns;
+	isc_result_t result;
+
+	REQUIRE(task == probe_task);
+	REQUIRE(trans->inuse == true);
+	REQUIRE(pns != NULL);
+	INSIST(outstanding_probes > 0);
+
+	for (name = ISC_LIST_HEAD(rev->answerlist); name != NULL;
+	     name = ISC_LIST_NEXT(name, link)) {
+		for (rdataset = ISC_LIST_HEAD(name->list);
+		     rdataset != NULL;
+		     rdataset = ISC_LIST_NEXT(rdataset, link)) {
+			(void)print_rdataset(rdataset, name);
+
+			if (rdataset->type != dns_rdatatype_a)
+				continue;
+
+			for (result = dns_rdataset_first(rdataset);
+			     result == ISC_R_SUCCESS;
+			     result = dns_rdataset_next(rdataset)) {
+				dns_rdata_in_a_t rdata_a;
+				struct server *server;
+
+				dns_rdataset_current(rdataset, &rdata);
+				result = dns_rdata_tostruct(&rdata, &rdata_a,
+							    NULL);
+				if (result != ISC_R_SUCCESS)
+					continue;
+
+				server = isc_mem_get(mctx, sizeof(*server));
+				if (server == NULL) {
+					fprintf(stderr, "resolve_nsaddress: "
+						"mem_get failed");
+					result = ISC_R_NOMEMORY;
+					POST(result);
+					goto cleanup;
+				}
+				isc_sockaddr_fromin(&server->address,
+						    &rdata_a.in_addr, 53);
+				ISC_LINK_INIT(server, link);
+				server->result_a = none;
+				server->result_aaaa = none;
+				ISC_LIST_APPEND(pns->servers, server, link);
+			}
+		}
+	}
+
+ cleanup:
+	dns_client_freeresanswer(client, &rev->answerlist);
+	dns_client_destroyrestrans(&trans->resid);
+	isc_event_free(&event);
+
+ next_ns:
+	trans->current_ns = ISC_LIST_NEXT(pns, link);
+	if (trans->current_ns == NULL) {
+		trans->current_ns = ISC_LIST_HEAD(trans->nslist);
+		dns_fixedname_invalidate(&trans->fixedname);
+		trans->qname = NULL;
+		result = set_nextqname(trans);
+		if (result == ISC_R_SUCCESS)
+			 result = probe_name(trans, dns_rdatatype_a);
+	} else {
+		result = fetch_nsaddress(trans);
+		if (result != ISC_R_SUCCESS)
+			goto next_ns; /* XXX: this is unlikely to succeed */
+	}
+
+	if (result != ISC_R_SUCCESS)
+		reset_probe(trans);
+}
+
+static isc_result_t
+fetch_nsaddress(struct probe_trans *trans) {
+	struct probe_ns *pns;
+
+	pns = trans->current_ns;
+	REQUIRE(pns != NULL);
+
+	return (dns_client_startresolve(client, pns->name, dns_rdataclass_in,
+					dns_rdatatype_a, 0, probe_task,
+					resolve_nsaddress, trans,
+					&trans->resid));
+}
+
+/*
+ * Get NS RRset for a given domain
+ */
+
+static void
+reset_probe(struct probe_trans *trans) {
+	struct probe_ns *pns;
+	struct server *server;
+	isc_result_t result;
+
+	REQUIRE(trans->resid == NULL);
+	REQUIRE(trans->reqid == NULL);
+
+	update_stat(trans);
+
+	dns_message_reset(trans->qmessage, DNS_MESSAGE_INTENTRENDER);
+	dns_message_reset(trans->rmessage, DNS_MESSAGE_INTENTPARSE);
+
+	trans->inuse = false;
+	if (trans->domain != NULL)
+		isc_mem_free(mctx, trans->domain);
+	trans->domain = NULL;
+	if (trans->qname != NULL)
+		dns_fixedname_invalidate(&trans->fixedname);
+	trans->qname = NULL;
+	trans->qlabel = qlabels;
+	trans->qname_found = false;
+	trans->current_ns = NULL;
+
+	while ((pns = ISC_LIST_HEAD(trans->nslist)) != NULL) {
+		ISC_LIST_UNLINK(trans->nslist, pns, link);
+		while ((server = ISC_LIST_HEAD(pns->servers)) != NULL) {
+			ISC_LIST_UNLINK(pns->servers, server, link);
+			isc_mem_put(mctx, server, sizeof(*server));
+		}
+		isc_mem_put(mctx, pns, sizeof(*pns));
+	}
+
+	outstanding_probes--;
+
+	result = probe_domain(trans);
+	if (result == ISC_R_NOMORE && outstanding_probes == 0)
+		isc_app_ctxshutdown(actx);
+}
+
+static void
+resolve_ns(isc_task_t *task, isc_event_t *event) {
+	struct probe_trans *trans = event->ev_arg;
+	dns_clientresevent_t *rev = (dns_clientresevent_t *)event;
+	dns_name_t *name;
+	dns_rdataset_t *rdataset;
+	isc_result_t result = ISC_R_SUCCESS;
+	dns_rdata_t rdata = DNS_RDATA_INIT;
+	struct probe_ns *pns;
+
+	REQUIRE(task == probe_task);
+	REQUIRE(trans->inuse == true);
+	INSIST(outstanding_probes > 0);
+
+	for (name = ISC_LIST_HEAD(rev->answerlist); name != NULL;
+	     name = ISC_LIST_NEXT(name, link)) {
+		for (rdataset = ISC_LIST_HEAD(name->list);
+		     rdataset != NULL;
+		     rdataset = ISC_LIST_NEXT(rdataset, link)) {
+			(void)print_rdataset(rdataset, name);
+
+			if (rdataset->type != dns_rdatatype_ns)
+				continue;
+
+			for (result = dns_rdataset_first(rdataset);
+			     result == ISC_R_SUCCESS;
+			     result = dns_rdataset_next(rdataset)) {
+				dns_rdata_ns_t ns;
+
+				dns_rdataset_current(rdataset, &rdata);
+				/*
+				 * Extract the name from the NS record.
+				 */
+				result = dns_rdata_tostruct(&rdata, &ns, NULL);
+				if (result != ISC_R_SUCCESS)
+					continue;
+
+				pns = isc_mem_get(mctx, sizeof(*pns));
+				if (pns == NULL) {
+					fprintf(stderr,
+						"resolve_ns: mem_get failed");
+					result = ISC_R_NOMEMORY;
+					POST(result);
+					/*
+					 * XXX: should we continue with the
+					 * available servers anyway?
+					 */
+					goto cleanup;
+				}
+
+				pns->name =
+				       dns_fixedname_initname(&pns->fixedname);
+				ISC_LINK_INIT(pns, link);
+				ISC_LIST_APPEND(trans->nslist, pns, link);
+				ISC_LIST_INIT(pns->servers);
+
+				dns_name_copy(&ns.name, pns->name, NULL);
+				dns_rdata_reset(&rdata);
+				dns_rdata_freestruct(&ns);
+			}
+		}
+	}
+
+ cleanup:
+	dns_client_freeresanswer(client, &rev->answerlist);
+	dns_client_destroyrestrans(&trans->resid);
+	isc_event_free(&event);
+
+	if (!ISC_LIST_EMPTY(trans->nslist)) {
+		/* Go get addresses of NSes */
+		trans->current_ns = ISC_LIST_HEAD(trans->nslist);
+		result = fetch_nsaddress(trans);
+	} else
+		result = ISC_R_FAILURE;
+
+	if (result == ISC_R_SUCCESS)
+		return;
+
+	reset_probe(trans);
+}
+
+static isc_result_t
+probe_domain(struct probe_trans *trans) {
+	isc_result_t result;
+	unsigned int domainlen;
+	isc_buffer_t b;
+	char buf[4096];	/* XXX ad hoc constant, but should be enough */
+	char *cp;
+
+	REQUIRE(trans != NULL);
+	REQUIRE(trans->inuse == false);
+	REQUIRE(outstanding_probes < MAX_PROBES);
+
+	/* Construct domain */
+	cp = fgets(buf, sizeof(buf), input);
+	if (cp == NULL)
+		return (ISC_R_NOMORE);
+	if ((cp = strchr(buf, '\n')) != NULL) /* zap NL if any */
+		*cp = '\0';
+	trans->domain = isc_mem_strdup(mctx, buf);
+	if (trans->domain == NULL) {
+		fprintf(stderr,
+			"failed to allocate memory for domain: %s", cp);
+		return (ISC_R_NOMEMORY);
+	}
+
+	/* Start getting NS for the domain */
+	domainlen = strlen(buf);
+	isc_buffer_init(&b, buf, domainlen);
+	isc_buffer_add(&b, domainlen);
+	trans->qname = dns_fixedname_initname(&trans->fixedname);
+	result = dns_name_fromtext(trans->qname, &b, dns_rootname, 0, NULL);
+	if (result != ISC_R_SUCCESS)
+		goto cleanup;
+	result = dns_client_startresolve(client, trans->qname,
+					 dns_rdataclass_in, dns_rdatatype_ns,
+					 0, probe_task, resolve_ns, trans,
+					 &trans->resid);
+	if (result != ISC_R_SUCCESS)
+		goto cleanup;
+
+	trans->inuse = true;
+	outstanding_probes++;
+
+	return (ISC_R_SUCCESS);
+
+ cleanup:
+	isc_mem_free(mctx, trans->domain);
+	dns_fixedname_invalidate(&trans->fixedname);
+
+	return (result);
+}
+
+ISC_PLATFORM_NORETURN_PRE static void
+usage(void) ISC_PLATFORM_NORETURN_POST;
+
+static void
+usage(void) {
+	fprintf(stderr, "usage: nsprobe [-d] [-v [-v...]] [-c cache_address] "
+		"[input_file]\n");
+
+	exit(1);
+}
+
+int
+main(int argc, char *argv[]) {
+	int i, ch, error;
+	struct addrinfo hints, *res;
+	isc_result_t result;
+	isc_sockaddr_t sa;
+	isc_sockaddrlist_t servers;
+	isc_taskmgr_t *taskmgr = NULL;
+	isc_socketmgr_t *socketmgr = NULL;
+	isc_timermgr_t *timermgr = NULL;
+
+	while ((ch = isc_commandline_parse(argc, argv, "c:dhv")) != -1) {
+		switch (ch) {
+		case 'c':
+			cacheserver = isc_commandline_argument;
+			break;
+		case 'd':
+			debug_mode = true;
+			break;
+		case 'h':
+			usage();
+			break;
+		case 'v':
+			verbose_level++;
+			break;
+		default:
+			usage();
+			break;
+		}
+	}
+
+	argc -= isc_commandline_index;
+	argv += isc_commandline_index;
+
+	/* Common set up */
+	isc_lib_register();
+	result = dns_lib_init();
+	if (result != ISC_R_SUCCESS) {
+		fprintf(stderr, "dns_lib_init failed: %u\n", result);
+		exit(1);
+	}
+
+	result = ctxs_init(&mctx, &actx, &taskmgr, &socketmgr,
+			   &timermgr);
+	if (result != ISC_R_SUCCESS) {
+		fprintf(stderr, "ctx create failed: %u\n", result);
+		exit(1);
+	}
+
+	isc_app_ctxstart(actx);
+
+	result = dns_client_createx(mctx, actx, taskmgr, socketmgr,
+				    timermgr, 0, &client);
+	if (result != ISC_R_SUCCESS) {
+		fprintf(stderr, "dns_client_createx failed: %u\n", result);
+		exit(1);
+	}
+
+	/* Set local cache server */
+	memset(&hints, 0, sizeof(hints));
+	hints.ai_family = AF_UNSPEC;
+	hints.ai_socktype = SOCK_DGRAM;
+	error = getaddrinfo(cacheserver, "53", &hints, &res);
+	if (error != 0) {
+		fprintf(stderr, "failed to convert server name (%s): %s\n",
+			cacheserver, gai_strerror(error));
+		exit(1);
+	}
+
+	if (res->ai_addrlen > sizeof(sa.type)) {
+		fprintf(stderr,
+			"assumption failure: addrlen is too long: %ld\n",
+			(long)res->ai_addrlen);
+		exit(1);
+	}
+	memmove(&sa.type.sa, res->ai_addr, res->ai_addrlen);
+	sa.length = (unsigned int)res->ai_addrlen;
+	freeaddrinfo(res);
+	ISC_LINK_INIT(&sa, link);
+	ISC_LIST_INIT(servers);
+	ISC_LIST_APPEND(servers, &sa, link);
+	result = dns_client_setservers(client, dns_rdataclass_in, NULL,
+				       &servers);
+	if (result != ISC_R_SUCCESS) {
+		fprintf(stderr, "failed to set server: %u\n", result);
+		exit(1);
+	}
+
+	/* Create the main task */
+	probe_task = NULL;
+	result = isc_task_create(taskmgr, 0, &probe_task);
+	if (result != ISC_R_SUCCESS) {
+		fprintf(stderr, "failed to create task: %u\n", result);
+		exit(1);
+	}
+
+	/* Open input file */
+	if (argc == 0)
+		input = stdin;
+	else {
+		input = fopen(argv[0], "r");
+		if (input == NULL) {
+			fprintf(stderr, "failed to open input file: %s\n",
+				argv[0]);
+			exit(1);
+		}
+	}
+
+	/* Set up and start probe */
+	for (i = 0; i < MAX_PROBES; i++) {
+		probes[i].inuse = false;
+		probes[i].domain = NULL;
+		dns_fixedname_init(&probes[i].fixedname);
+		probes[i].qname = NULL;
+		probes[i].qlabel = qlabels;
+		probes[i].qname_found = false;
+		probes[i].resid = NULL;
+		ISC_LIST_INIT(probes[i].nslist);
+		probes[i].reqid = NULL;
+
+		probes[i].qmessage = NULL;
+		result = dns_message_create(mctx, DNS_MESSAGE_INTENTRENDER,
+					    &probes[i].qmessage);
+		if (result == ISC_R_SUCCESS) {
+			result = dns_message_create(mctx,
+						    DNS_MESSAGE_INTENTPARSE,
+						    &probes[i].rmessage);
+		}
+		if (result != ISC_R_SUCCESS) {
+			fprintf(stderr, "initialization failure\n");
+			exit(1);
+		}
+	}
+	for (i = 0; i < MAX_PROBES; i++) {
+		result = probe_domain(&probes[i]);
+		if (result == ISC_R_NOMORE)
+			break;
+		else if (result != ISC_R_SUCCESS) {
+			fprintf(stderr, "failed to issue an initial probe\n");
+			exit(1);
+		}
+	}
+
+	/* Start event loop */
+	isc_app_ctxrun(actx);
+
+	/* Dump results */
+	printf("Per domain results (out of %lu domains):\n",
+	       number_of_domains);
+	printf("  valid: %lu\n"
+	       "  ignore: %lu\n"
+	       "  nxdomain: %lu\n"
+	       "  othererr: %lu\n"
+	       "  multiplesoa: %lu\n"
+	       "  multiplecname: %lu\n"
+	       "  brokenanswer: %lu\n"
+	       "  lame: %lu\n"
+	       "  unknown: %lu\n"
+	       "  multiple errors: %lu\n",
+	       domain_stat.valid, domain_stat.ignore, domain_stat.nxdomain,
+	       domain_stat.othererr, domain_stat.multiplesoa,
+	       domain_stat.multiplecname, domain_stat.brokenanswer,
+	       domain_stat.lame, domain_stat.unknown, multiple_error_domains);
+	printf("Per server results (out of %lu servers):\n",
+	       number_of_servers);
+	printf("  valid: %lu\n"
+	       "  ignore: %lu\n"
+	       "  nxdomain: %lu\n"
+	       "  othererr: %lu\n"
+	       "  multiplesoa: %lu\n"
+	       "  multiplecname: %lu\n"
+	       "  brokenanswer: %lu\n"
+	       "  lame: %lu\n"
+	       "  unknown: %lu\n",
+	       server_stat.valid, server_stat.ignore, server_stat.nxdomain,
+	       server_stat.othererr, server_stat.multiplesoa,
+	       server_stat.multiplecname, server_stat.brokenanswer,
+	       server_stat.lame, server_stat.unknown);
+
+	/* Cleanup */
+	for (i = 0; i < MAX_PROBES; i++) {
+		dns_message_destroy(&probes[i].qmessage);
+		dns_message_destroy(&probes[i].rmessage);
+	}
+	isc_task_detach(&probe_task);
+	dns_client_destroy(&client);
+	dns_lib_shutdown();
+	isc_app_ctxfinish(actx);
+	ctxs_destroy(&mctx, &actx, &taskmgr, &socketmgr, &timermgr);
+
+	return (0);
+}