added unbound to external deps

1 files changed, 1227 insertions, 0 deletions

diff --git a/external/unbound/libunbound/libunbound.c b/external/unbound/libunbound/libunbound.c
new file mode 100644
index 000000000..78d31968a
--- /dev/null
+++ b/external/unbound/libunbound/libunbound.c
@@ -0,0 +1,1227 @@
+/*
+ * unbound.c - unbound validating resolver public API implementation
+ *
+ * Copyright (c) 2007, NLnet Labs. All rights reserved.
+ *
+ * This software is open source.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 
+ * Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * 
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * 
+ * Neither the name of the NLNET LABS nor the names of its contributors may
+ * be used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/**
+ * \file
+ *
+ * This file contains functions to resolve DNS queries and 
+ * validate the answers. Synchonously and asynchronously.
+ *
+ */
+
+/* include the public api first, it should be able to stand alone */
+#include "libunbound/unbound.h"
+#include "libunbound/unbound-event.h"
+#include "config.h"
+#include <ctype.h>
+#include "libunbound/context.h"
+#include "libunbound/libworker.h"
+#include "util/locks.h"
+#include "util/config_file.h"
+#include "util/alloc.h"
+#include "util/module.h"
+#include "util/regional.h"
+#include "util/log.h"
+#include "util/random.h"
+#include "util/net_help.h"
+#include "util/tube.h"
+#include "services/modstack.h"
+#include "services/localzone.h"
+#include "services/cache/infra.h"
+#include "services/cache/rrset.h"
+#include "ldns/sbuffer.h"
+#ifdef HAVE_PTHREAD
+#include <signal.h>
+#endif
+
+#if defined(UB_ON_WINDOWS) && defined (HAVE_WINDOWS_H)
+#include <windows.h>
+#include <iphlpapi.h>
+#endif /* UB_ON_WINDOWS */
+
+/** create context functionality, but no pipes */
+static struct ub_ctx* ub_ctx_create_nopipe(void)
+{
+	struct ub_ctx* ctx;
+	unsigned int seed;
+#ifdef USE_WINSOCK
+	int r;
+	WSADATA wsa_data;
+#endif
+	
+	log_init(NULL, 0, NULL); /* logs to stderr */
+	log_ident_set("libunbound");
+#ifdef USE_WINSOCK
+	if((r = WSAStartup(MAKEWORD(2,2), &wsa_data)) != 0) {
+		log_err("could not init winsock. WSAStartup: %s",
+			wsa_strerror(r));
+		return NULL;
+	}
+#endif
+	verbosity = 0; /* errors only */
+	checklock_start();
+	ctx = (struct ub_ctx*)calloc(1, sizeof(*ctx));
+	if(!ctx) {
+		errno = ENOMEM;
+		return NULL;
+	}
+	alloc_init(&ctx->superalloc, NULL, 0);
+	seed = (unsigned int)time(NULL) ^ (unsigned int)getpid();
+	if(!(ctx->seed_rnd = ub_initstate(seed, NULL))) {
+		seed = 0;
+		ub_randfree(ctx->seed_rnd);
+		free(ctx);
+		errno = ENOMEM;
+		return NULL;
+	}
+	seed = 0;
+	lock_basic_init(&ctx->qqpipe_lock);
+	lock_basic_init(&ctx->rrpipe_lock);
+	lock_basic_init(&ctx->cfglock);
+	ctx->env = (struct module_env*)calloc(1, sizeof(*ctx->env));
+	if(!ctx->env) {
+		ub_randfree(ctx->seed_rnd);
+		free(ctx);
+		errno = ENOMEM;
+		return NULL;
+	}
+	ctx->env->cfg = config_create_forlib();
+	if(!ctx->env->cfg) {
+		free(ctx->env);
+		ub_randfree(ctx->seed_rnd);
+		free(ctx);
+		errno = ENOMEM;
+		return NULL;
+	}
+	ctx->env->alloc = &ctx->superalloc;
+	ctx->env->worker = NULL;
+	ctx->env->need_to_validate = 0;
+	modstack_init(&ctx->mods);
+	rbtree_init(&ctx->queries, &context_query_cmp);
+	return ctx;
+}
+
+struct ub_ctx* 
+ub_ctx_create(void)
+{
+	struct ub_ctx* ctx = ub_ctx_create_nopipe();
+	if(!ctx)
+		return NULL;
+	if((ctx->qq_pipe = tube_create()) == NULL) {
+		int e = errno;
+		ub_randfree(ctx->seed_rnd);
+		config_delete(ctx->env->cfg);
+		modstack_desetup(&ctx->mods, ctx->env);
+		free(ctx->env);
+		free(ctx);
+		errno = e;
+		return NULL;
+	}
+	if((ctx->rr_pipe = tube_create()) == NULL) {
+		int e = errno;
+		tube_delete(ctx->qq_pipe);
+		ub_randfree(ctx->seed_rnd);
+		config_delete(ctx->env->cfg);
+		modstack_desetup(&ctx->mods, ctx->env);
+		free(ctx->env);
+		free(ctx);
+		errno = e;
+		return NULL;
+	}
+	return ctx;
+}
+
+struct ub_ctx* 
+ub_ctx_create_event(struct event_base* eb)
+{
+	struct ub_ctx* ctx = ub_ctx_create_nopipe();
+	if(!ctx)
+		return NULL;
+	/* no pipes, but we have the locks to make sure everything works */
+	ctx->created_bg = 0;
+	ctx->dothread = 1; /* the processing is in the same process,
+		makes ub_cancel and ub_ctx_delete do the right thing */
+	ctx->event_base = eb;
+	return ctx;
+}
+	
+/** delete q */
+static void
+delq(rbnode_t* n, void* ATTR_UNUSED(arg))
+{
+	struct ctx_query* q = (struct ctx_query*)n;
+	context_query_delete(q);
+}
+
+/** stop the bg thread */
+static void ub_stop_bg(struct ub_ctx* ctx)
+{
+	/* stop the bg thread */
+	lock_basic_lock(&ctx->cfglock);
+	if(ctx->created_bg) {
+		uint8_t* msg;
+		uint32_t len;
+		uint32_t cmd = UB_LIBCMD_QUIT;
+		lock_basic_unlock(&ctx->cfglock);
+		lock_basic_lock(&ctx->qqpipe_lock);
+		(void)tube_write_msg(ctx->qq_pipe, (uint8_t*)&cmd, 
+			(uint32_t)sizeof(cmd), 0);
+		lock_basic_unlock(&ctx->qqpipe_lock);
+		lock_basic_lock(&ctx->rrpipe_lock);
+		while(tube_read_msg(ctx->rr_pipe, &msg, &len, 0)) {
+			/* discard all results except a quit confirm */
+			if(context_serial_getcmd(msg, len) == UB_LIBCMD_QUIT) {
+				free(msg);
+				break;
+			}
+			free(msg);
+		}
+		lock_basic_unlock(&ctx->rrpipe_lock);
+
+		/* if bg worker is a thread, wait for it to exit, so that all
+	 	 * resources are really gone. */
+		lock_basic_lock(&ctx->cfglock);
+		if(ctx->dothread) {
+			lock_basic_unlock(&ctx->cfglock);
+			ub_thread_join(ctx->bg_tid);
+		} else {
+			lock_basic_unlock(&ctx->cfglock);
+		}
+	}
+	else {
+		lock_basic_unlock(&ctx->cfglock);
+	}
+}
+
+void 
+ub_ctx_delete(struct ub_ctx* ctx)
+{
+	struct alloc_cache* a, *na;
+	int do_stop = 1;
+	if(!ctx) return;
+
+	/* see if bg thread is created and if threads have been killed */
+	/* no locks, because those may be held by terminated threads */
+	/* for processes the read pipe is closed and we see that on read */
+#ifdef HAVE_PTHREAD
+	if(ctx->created_bg && ctx->dothread) {
+		if(pthread_kill(ctx->bg_tid, 0) == ESRCH) {
+			/* thread has been killed */
+			do_stop = 0;
+		}
+	}
+#endif /* HAVE_PTHREAD */
+	if(do_stop)
+		ub_stop_bg(ctx);
+	libworker_delete_event(ctx->event_worker);
+
+	modstack_desetup(&ctx->mods, ctx->env);
+	a = ctx->alloc_list;
+	while(a) {
+		na = a->super;
+		a->super = &ctx->superalloc;
+		alloc_clear(a);
+		free(a);
+		a = na;
+	}
+	local_zones_delete(ctx->local_zones);
+	lock_basic_destroy(&ctx->qqpipe_lock);
+	lock_basic_destroy(&ctx->rrpipe_lock);
+	lock_basic_destroy(&ctx->cfglock);
+	tube_delete(ctx->qq_pipe);
+	tube_delete(ctx->rr_pipe);
+	if(ctx->env) {
+		slabhash_delete(ctx->env->msg_cache);
+		rrset_cache_delete(ctx->env->rrset_cache);
+		infra_delete(ctx->env->infra_cache);
+		config_delete(ctx->env->cfg);
+		free(ctx->env);
+	}
+	ub_randfree(ctx->seed_rnd);
+	alloc_clear(&ctx->superalloc);
+	traverse_postorder(&ctx->queries, delq, NULL);
+	free(ctx);
+#ifdef USE_WINSOCK
+	WSACleanup();
+#endif
+}
+
+int 
+ub_ctx_set_option(struct ub_ctx* ctx, const char* opt, const char* val)
+{
+	lock_basic_lock(&ctx->cfglock);
+	if(ctx->finalized) {
+		lock_basic_unlock(&ctx->cfglock);
+		return UB_AFTERFINAL;
+	}
+	if(!config_set_option(ctx->env->cfg, opt, val)) {
+		lock_basic_unlock(&ctx->cfglock);
+		return UB_SYNTAX;
+	}
+	lock_basic_unlock(&ctx->cfglock);
+	return UB_NOERROR;
+}
+
+int
+ub_ctx_get_option(struct ub_ctx* ctx, const char* opt, char** str)
+{
+	int r;
+	lock_basic_lock(&ctx->cfglock);
+	r = config_get_option_collate(ctx->env->cfg, opt, str);
+	lock_basic_unlock(&ctx->cfglock);
+	if(r == 0) r = UB_NOERROR;
+	else if(r == 1) r = UB_SYNTAX;
+	else if(r == 2) r = UB_NOMEM;
+	return r;
+}
+
+int 
+ub_ctx_config(struct ub_ctx* ctx, const char* fname)
+{
+	lock_basic_lock(&ctx->cfglock);
+	if(ctx->finalized) {
+		lock_basic_unlock(&ctx->cfglock);
+		return UB_AFTERFINAL;
+	}
+	if(!config_read(ctx->env->cfg, fname, NULL)) {
+		lock_basic_unlock(&ctx->cfglock);
+		return UB_SYNTAX;
+	}
+	lock_basic_unlock(&ctx->cfglock);
+	return UB_NOERROR;
+}
+
+int 
+ub_ctx_add_ta(struct ub_ctx* ctx, const char* ta)
+{
+	char* dup = strdup(ta);
+	if(!dup) return UB_NOMEM;
+	lock_basic_lock(&ctx->cfglock);
+	if(ctx->finalized) {
+		lock_basic_unlock(&ctx->cfglock);
+		free(dup);
+		return UB_AFTERFINAL;
+	}
+	if(!cfg_strlist_insert(&ctx->env->cfg->trust_anchor_list, dup)) {
+		lock_basic_unlock(&ctx->cfglock);
+		free(dup);
+		return UB_NOMEM;
+	}
+	lock_basic_unlock(&ctx->cfglock);
+	return UB_NOERROR;
+}
+
+int 
+ub_ctx_add_ta_file(struct ub_ctx* ctx, const char* fname)
+{
+	char* dup = strdup(fname);
+	if(!dup) return UB_NOMEM;
+	lock_basic_lock(&ctx->cfglock);
+	if(ctx->finalized) {
+		lock_basic_unlock(&ctx->cfglock);
+		free(dup);
+		return UB_AFTERFINAL;
+	}
+	if(!cfg_strlist_insert(&ctx->env->cfg->trust_anchor_file_list, dup)) {
+		lock_basic_unlock(&ctx->cfglock);
+		free(dup);
+		return UB_NOMEM;
+	}
+	lock_basic_unlock(&ctx->cfglock);
+	return UB_NOERROR;
+}
+
+int 
+ub_ctx_trustedkeys(struct ub_ctx* ctx, const char* fname)
+{
+	char* dup = strdup(fname);
+	if(!dup) return UB_NOMEM;
+	lock_basic_lock(&ctx->cfglock);
+	if(ctx->finalized) {
+		lock_basic_unlock(&ctx->cfglock);
+		free(dup);
+		return UB_AFTERFINAL;
+	}
+	if(!cfg_strlist_insert(&ctx->env->cfg->trusted_keys_file_list, dup)) {
+		lock_basic_unlock(&ctx->cfglock);
+		free(dup);
+		return UB_NOMEM;
+	}
+	lock_basic_unlock(&ctx->cfglock);
+	return UB_NOERROR;
+}
+
+int
+ub_ctx_debuglevel(struct ub_ctx* ctx, int d)
+{
+	lock_basic_lock(&ctx->cfglock);
+	verbosity = d;
+	ctx->env->cfg->verbosity = d;
+	lock_basic_unlock(&ctx->cfglock);
+	return UB_NOERROR;
+}
+
+int ub_ctx_debugout(struct ub_ctx* ctx, void* out)
+{
+	lock_basic_lock(&ctx->cfglock);
+	log_file((FILE*)out);
+	ctx->logfile_override = 1;
+	ctx->log_out = out;
+	lock_basic_unlock(&ctx->cfglock);
+	return UB_NOERROR;
+}
+
+int 
+ub_ctx_async(struct ub_ctx* ctx, int dothread)
+{
+#ifdef THREADS_DISABLED
+	if(dothread) /* cannot do threading */
+		return UB_NOERROR;
+#endif
+	lock_basic_lock(&ctx->cfglock);
+	if(ctx->finalized) {
+		lock_basic_unlock(&ctx->cfglock);
+		return UB_AFTERFINAL;
+	}
+	ctx->dothread = dothread;
+	lock_basic_unlock(&ctx->cfglock);
+	return UB_NOERROR;
+}
+
+int 
+ub_poll(struct ub_ctx* ctx)
+{
+	/* no need to hold lock while testing for readability. */
+	return tube_poll(ctx->rr_pipe);
+}
+
+int 
+ub_fd(struct ub_ctx* ctx)
+{
+	return tube_read_fd(ctx->rr_pipe);
+}
+
+/** process answer from bg worker */
+static int
+process_answer_detail(struct ub_ctx* ctx, uint8_t* msg, uint32_t len,
+	ub_callback_t* cb, void** cbarg, int* err,
+	struct ub_result** res)
+{
+	struct ctx_query* q;
+	if(context_serial_getcmd(msg, len) != UB_LIBCMD_ANSWER) {
+		log_err("error: bad data from bg worker %d",
+			(int)context_serial_getcmd(msg, len));
+		return 0;
+	}
+
+	lock_basic_lock(&ctx->cfglock);
+	q = context_deserialize_answer(ctx, msg, len, err);
+	if(!q) {
+		lock_basic_unlock(&ctx->cfglock);
+		/* probably simply the lookup that failed, i.e.
+		 * response returned before cancel was sent out, so noerror */
+		return 1;
+	}
+	log_assert(q->async);
+
+	/* grab cb while locked */
+	if(q->cancelled) {
+		*cb = NULL;
+		*cbarg = NULL;
+	} else {
+		*cb = q->cb;
+		*cbarg = q->cb_arg;
+	}
+	if(*err) {
+		*res = NULL;
+		ub_resolve_free(q->res);
+	} else {
+		/* parse the message, extract rcode, fill result */
+		sldns_buffer* buf = sldns_buffer_new(q->msg_len);
+		struct regional* region = regional_create();
+		*res = q->res;
+		(*res)->rcode = LDNS_RCODE_SERVFAIL;
+		if(region && buf) {
+			sldns_buffer_clear(buf);
+			sldns_buffer_write(buf, q->msg, q->msg_len);
+			sldns_buffer_flip(buf);
+			libworker_enter_result(*res, buf, region,
+				q->msg_security);
+		}
+		(*res)->answer_packet = q->msg;
+		(*res)->answer_len = (int)q->msg_len;
+		q->msg = NULL;
+		sldns_buffer_free(buf);
+		regional_destroy(region);
+	}
+	q->res = NULL;
+	/* delete the q from list */
+	(void)rbtree_delete(&ctx->queries, q->node.key);
+	ctx->num_async--;
+	context_query_delete(q);
+	lock_basic_unlock(&ctx->cfglock);
+
+	if(*cb) return 2;
+	ub_resolve_free(*res);
+	return 1;
+}
+
+/** process answer from bg worker */
+static int
+process_answer(struct ub_ctx* ctx, uint8_t* msg, uint32_t len)
+{
+	int err;
+	ub_callback_t cb;
+	void* cbarg;
+	struct ub_result* res;
+	int r;
+
+	r = process_answer_detail(ctx, msg, len, &cb, &cbarg, &err, &res);
+
+	/* no locks held while calling callback, so that library is
+	 * re-entrant. */
+	if(r == 2)
+		(*cb)(cbarg, err, res);
+
+	return r;
+}
+
+int 
+ub_process(struct ub_ctx* ctx)
+{
+	int r;
+	uint8_t* msg;
+	uint32_t len;
+	while(1) {
+		msg = NULL;
+		lock_basic_lock(&ctx->rrpipe_lock);
+		r = tube_read_msg(ctx->rr_pipe, &msg, &len, 1);
+		lock_basic_unlock(&ctx->rrpipe_lock);
+		if(r == 0)
+			return UB_PIPE;
+		else if(r == -1)
+			break;
+		if(!process_answer(ctx, msg, len)) {
+			free(msg);
+			return UB_PIPE;
+		}
+		free(msg);
+	}
+	return UB_NOERROR;
+}
+
+int 
+ub_wait(struct ub_ctx* ctx)
+{
+	int err;
+	ub_callback_t cb;
+	void* cbarg;
+	struct ub_result* res;
+	int r;
+	uint8_t* msg;
+	uint32_t len;
+	/* this is basically the same loop as _process(), but with changes.
+	 * holds the rrpipe lock and waits with tube_wait */
+	while(1) {
+		lock_basic_lock(&ctx->rrpipe_lock);
+		lock_basic_lock(&ctx->cfglock);
+		if(ctx->num_async == 0) {
+			lock_basic_unlock(&ctx->cfglock);
+			lock_basic_unlock(&ctx->rrpipe_lock);
+			break;
+		}
+		lock_basic_unlock(&ctx->cfglock);
+
+		/* keep rrpipe locked, while
+		 * 	o waiting for pipe readable
+		 * 	o parsing message
+		 * 	o possibly decrementing num_async
+		 * do callback without lock
+		 */
+		r = tube_wait(ctx->rr_pipe);
+		if(r) {
+			r = tube_read_msg(ctx->rr_pipe, &msg, &len, 1);
+			if(r == 0) {
+				lock_basic_unlock(&ctx->rrpipe_lock);
+				return UB_PIPE;
+			}
+			if(r == -1) {
+				lock_basic_unlock(&ctx->rrpipe_lock);
+				continue;
+			}
+			r = process_answer_detail(ctx, msg, len, 
+				&cb, &cbarg, &err, &res);
+			lock_basic_unlock(&ctx->rrpipe_lock);
+			free(msg);
+			if(r == 0)
+				return UB_PIPE;
+			if(r == 2)
+				(*cb)(cbarg, err, res);
+		} else {
+			lock_basic_unlock(&ctx->rrpipe_lock);
+		}
+	}
+	return UB_NOERROR;
+}
+
+int 
+ub_resolve(struct ub_ctx* ctx, const char* name, int rrtype, 
+	int rrclass, struct ub_result** result)
+{
+	struct ctx_query* q;
+	int r;
+	*result = NULL;
+
+	lock_basic_lock(&ctx->cfglock);
+	if(!ctx->finalized) {
+		r = context_finalize(ctx);
+		if(r) {
+			lock_basic_unlock(&ctx->cfglock);
+			return r;
+		}
+	}
+	/* create new ctx_query and attempt to add to the list */
+	lock_basic_unlock(&ctx->cfglock);
+	q = context_new(ctx, name, rrtype, rrclass, NULL, NULL);
+	if(!q)
+		return UB_NOMEM;
+	/* become a resolver thread for a bit */
+
+	r = libworker_fg(ctx, q);
+	if(r) {
+		lock_basic_lock(&ctx->cfglock);
+		(void)rbtree_delete(&ctx->queries, q->node.key);
+		context_query_delete(q);
+		lock_basic_unlock(&ctx->cfglock);
+		return r;
+	}
+	q->res->answer_packet = q->msg;
+	q->res->answer_len = (int)q->msg_len;
+	q->msg = NULL;
+	*result = q->res;
+	q->res = NULL;
+
+	lock_basic_lock(&ctx->cfglock);
+	(void)rbtree_delete(&ctx->queries, q->node.key);
+	context_query_delete(q);
+	lock_basic_unlock(&ctx->cfglock);
+	return UB_NOERROR;
+}
+
+int 
+ub_resolve_event(struct ub_ctx* ctx, const char* name, int rrtype, 
+	int rrclass, void* mydata, ub_event_callback_t callback, int* async_id)
+{
+	struct ctx_query* q;
+	int r;
+
+	if(async_id)
+		*async_id = 0;
+	lock_basic_lock(&ctx->cfglock);
+	if(!ctx->finalized) {
+		int r = context_finalize(ctx);
+		if(r) {
+			lock_basic_unlock(&ctx->cfglock);
+			return r;
+		}
+	}
+	lock_basic_unlock(&ctx->cfglock);
+	if(!ctx->event_worker) {
+		ctx->event_worker = libworker_create_event(ctx,
+			ctx->event_base);
+		if(!ctx->event_worker) {
+			return UB_INITFAIL;
+		}
+	}
+
+	/* create new ctx_query and attempt to add to the list */
+	q = context_new(ctx, name, rrtype, rrclass, (ub_callback_t)callback,
+		mydata);
+	if(!q)
+		return UB_NOMEM;
+
+	/* attach to mesh */
+	if((r=libworker_attach_mesh(ctx, q, async_id)) != 0)
+		return r;
+	return UB_NOERROR;
+}
+
+
+int 
+ub_resolve_async(struct ub_ctx* ctx, const char* name, int rrtype, 
+	int rrclass, void* mydata, ub_callback_t callback, int* async_id)
+{
+	struct ctx_query* q;
+	uint8_t* msg = NULL;
+	uint32_t len = 0;
+
+	if(async_id)
+		*async_id = 0;
+	lock_basic_lock(&ctx->cfglock);
+	if(!ctx->finalized) {
+		int r = context_finalize(ctx);
+		if(r) {
+			lock_basic_unlock(&ctx->cfglock);
+			return r;
+		}
+	}
+	if(!ctx->created_bg) {
+		int r;
+		ctx->created_bg = 1;
+		lock_basic_unlock(&ctx->cfglock);
+		r = libworker_bg(ctx);
+		if(r) {
+			lock_basic_lock(&ctx->cfglock);
+			ctx->created_bg = 0;
+			lock_basic_unlock(&ctx->cfglock);
+			return r;
+		}
+	} else {
+		lock_basic_unlock(&ctx->cfglock);
+	}
+
+	/* create new ctx_query and attempt to add to the list */
+	q = context_new(ctx, name, rrtype, rrclass, callback, mydata);
+	if(!q)
+		return UB_NOMEM;
+
+	/* write over pipe to background worker */
+	lock_basic_lock(&ctx->cfglock);
+	msg = context_serialize_new_query(q, &len);
+	if(!msg) {
+		(void)rbtree_delete(&ctx->queries, q->node.key);
+		ctx->num_async--;
+		context_query_delete(q);
+		lock_basic_unlock(&ctx->cfglock);
+		return UB_NOMEM;
+	}
+	if(async_id)
+		*async_id = q->querynum;
+	lock_basic_unlock(&ctx->cfglock);
+	
+	lock_basic_lock(&ctx->qqpipe_lock);
+	if(!tube_write_msg(ctx->qq_pipe, msg, len, 0)) {
+		lock_basic_unlock(&ctx->qqpipe_lock);
+		free(msg);
+		return UB_PIPE;
+	}
+	lock_basic_unlock(&ctx->qqpipe_lock);
+	free(msg);
+	return UB_NOERROR;
+}
+
+int 
+ub_cancel(struct ub_ctx* ctx, int async_id)
+{
+	struct ctx_query* q;
+	uint8_t* msg = NULL;
+	uint32_t len = 0;
+	lock_basic_lock(&ctx->cfglock);
+	q = (struct ctx_query*)rbtree_search(&ctx->queries, &async_id);
+	if(!q || !q->async) {
+		/* it is not there, so nothing to do */
+		lock_basic_unlock(&ctx->cfglock);
+		return UB_NOID;
+	}
+	log_assert(q->async);
+	q->cancelled = 1;
+	
+	/* delete it */
+	if(!ctx->dothread) { /* if forked */
+		(void)rbtree_delete(&ctx->queries, q->node.key);
+		ctx->num_async--;
+		msg = context_serialize_cancel(q, &len);
+		context_query_delete(q);
+		lock_basic_unlock(&ctx->cfglock);
+		if(!msg) {
+			return UB_NOMEM;
+		}
+		/* send cancel to background worker */
+		lock_basic_lock(&ctx->qqpipe_lock);
+		if(!tube_write_msg(ctx->qq_pipe, msg, len, 0)) {
+			lock_basic_unlock(&ctx->qqpipe_lock);
+			free(msg);
+			return UB_PIPE;
+		}
+		lock_basic_unlock(&ctx->qqpipe_lock);
+		free(msg);
+	} else {
+		lock_basic_unlock(&ctx->cfglock);
+	}
+	return UB_NOERROR;
+}
+
+void 
+ub_resolve_free(struct ub_result* result)
+{
+	char** p;
+	if(!result) return;
+	free(result->qname);
+	if(result->canonname != result->qname)
+		free(result->canonname);
+	if(result->data)
+		for(p = result->data; *p; p++)
+			free(*p);
+	free(result->data);
+	free(result->len);
+	free(result->answer_packet);
+	free(result->why_bogus);
+	free(result);
+}
+
+const char* 
+ub_strerror(int err)
+{
+	switch(err) {
+		case UB_NOERROR: return "no error";
+		case UB_SOCKET: return "socket io error";
+		case UB_NOMEM: return "out of memory";
+		case UB_SYNTAX: return "syntax error";
+		case UB_SERVFAIL: return "server failure";
+		case UB_FORKFAIL: return "could not fork";
+		case UB_INITFAIL: return "initialization failure";
+		case UB_AFTERFINAL: return "setting change after finalize";
+		case UB_PIPE: return "error in pipe communication with async";
+		case UB_READFILE: return "error reading file";
+		case UB_NOID: return "error async_id does not exist";
+		default: return "unknown error";
+	}
+}
+
+int 
+ub_ctx_set_fwd(struct ub_ctx* ctx, const char* addr)
+{
+	struct sockaddr_storage storage;
+	socklen_t stlen;
+	struct config_stub* s;
+	char* dupl;
+	lock_basic_lock(&ctx->cfglock);
+	if(ctx->finalized) {
+		lock_basic_unlock(&ctx->cfglock);
+		errno=EINVAL;
+		return UB_AFTERFINAL;
+	}
+	if(!addr) {
+		/* disable fwd mode - the root stub should be first. */
+		if(ctx->env->cfg->forwards &&
+			strcmp(ctx->env->cfg->forwards->name, ".") == 0) {
+			s = ctx->env->cfg->forwards;
+			ctx->env->cfg->forwards = s->next;
+			s->next = NULL;
+			config_delstubs(s);
+		}
+		lock_basic_unlock(&ctx->cfglock);
+		return UB_NOERROR;
+	}
+	lock_basic_unlock(&ctx->cfglock);
+
+	/* check syntax for addr */
+	if(!extstrtoaddr(addr, &storage, &stlen)) {
+		errno=EINVAL;
+		return UB_SYNTAX;
+	}
+	
+	/* it parses, add root stub in front of list */
+	lock_basic_lock(&ctx->cfglock);
+	if(!ctx->env->cfg->forwards ||
+		strcmp(ctx->env->cfg->forwards->name, ".") != 0) {
+		s = calloc(1, sizeof(*s));
+		if(!s) {
+			lock_basic_unlock(&ctx->cfglock);
+			errno=ENOMEM;
+			return UB_NOMEM;
+		}
+		s->name = strdup(".");
+		if(!s->name) {
+			free(s);
+			lock_basic_unlock(&ctx->cfglock);
+			errno=ENOMEM;
+			return UB_NOMEM;
+		}
+		s->next = ctx->env->cfg->forwards;
+		ctx->env->cfg->forwards = s;
+	} else {
+		log_assert(ctx->env->cfg->forwards);
+		s = ctx->env->cfg->forwards;
+	}
+	dupl = strdup(addr);
+	if(!dupl) {
+		lock_basic_unlock(&ctx->cfglock);
+		errno=ENOMEM;
+		return UB_NOMEM;
+	}
+	if(!cfg_strlist_insert(&s->addrs, dupl)) {
+		free(dupl);
+		lock_basic_unlock(&ctx->cfglock);
+		errno=ENOMEM;
+		return UB_NOMEM;
+	}
+	lock_basic_unlock(&ctx->cfglock);
+	return UB_NOERROR;
+}
+
+int 
+ub_ctx_resolvconf(struct ub_ctx* ctx, const char* fname)
+{
+	FILE* in;
+	int numserv = 0;
+	char buf[1024];
+	char* parse, *addr;
+	int r;
+
+	if(fname == NULL) {
+#if !defined(UB_ON_WINDOWS) || !defined(HAVE_WINDOWS_H)
+		fname = "/etc/resolv.conf";
+#else
+		FIXED_INFO *info;
+		ULONG buflen = sizeof(*info);
+		IP_ADDR_STRING *ptr;
+
+		info = (FIXED_INFO *) malloc(sizeof (FIXED_INFO));
+		if (info == NULL) 
+			return UB_READFILE;
+
+		if (GetNetworkParams(info, &buflen) == ERROR_BUFFER_OVERFLOW) {
+			free(info);
+			info = (FIXED_INFO *) malloc(buflen);
+			if (info == NULL)
+				return UB_READFILE;
+		}
+
+		if (GetNetworkParams(info, &buflen) == NO_ERROR) {
+			int retval=0;
+			ptr = &(info->DnsServerList);
+			while (ptr) {
+				numserv++;
+				if((retval=ub_ctx_set_fwd(ctx, 
+					ptr->IpAddress.String)!=0)) {
+					free(info);
+					return retval;
+				}
+				ptr = ptr->Next;
+			}
+			free(info);
+			if (numserv==0)
+				return UB_READFILE;
+			return UB_NOERROR;
+		}
+		free(info);
+		return UB_READFILE;
+#endif /* WINDOWS */
+	}
+	in = fopen(fname, "r");
+	if(!in) {
+		/* error in errno! perror(fname) */
+		return UB_READFILE;
+	}
+	while(fgets(buf, (int)sizeof(buf), in)) {
+		buf[sizeof(buf)-1] = 0;
+		parse=buf;
+		while(*parse == ' ' || *parse == '\t')
+			parse++;
+		if(strncmp(parse, "nameserver", 10) == 0) {
+			numserv++;
+			parse += 10; /* skip 'nameserver' */
+			/* skip whitespace */
+			while(*parse == ' ' || *parse == '\t')
+				parse++;
+			addr = parse;
+			/* skip [0-9a-fA-F.:]*, i.e. IP4 and IP6 address */
+			while(isxdigit(*parse) || *parse=='.' || *parse==':')
+				parse++;
+			/* terminate after the address, remove newline */
+			*parse = 0;
+			
+			if((r = ub_ctx_set_fwd(ctx, addr)) != UB_NOERROR) {
+				fclose(in);
+				return r;
+			}
+		}
+	}
+	fclose(in);
+	if(numserv == 0) {
+		/* from resolv.conf(5) if none given, use localhost */
+		return ub_ctx_set_fwd(ctx, "127.0.0.1");
+	}
+	return UB_NOERROR;
+}
+
+int
+ub_ctx_hosts(struct ub_ctx* ctx, const char* fname)
+{
+	FILE* in;
+	char buf[1024], ldata[1024];
+	char* parse, *addr, *name, *ins;
+	lock_basic_lock(&ctx->cfglock);
+	if(ctx->finalized) {
+		lock_basic_unlock(&ctx->cfglock);
+		errno=EINVAL;
+		return UB_AFTERFINAL;
+	}
+	lock_basic_unlock(&ctx->cfglock);
+	if(fname == NULL) {
+#if defined(UB_ON_WINDOWS) && defined(HAVE_WINDOWS_H)
+		/*
+		 * If this is Windows NT/XP/2K it's in
+		 * %WINDIR%\system32\drivers\etc\hosts.
+		 * If this is Windows 95/98/Me it's in %WINDIR%\hosts.
+		 */
+		name = getenv("WINDIR");
+		if (name != NULL) {
+			int retval=0;
+			snprintf(buf, sizeof(buf), "%s%s", name, 
+				"\\system32\\drivers\\etc\\hosts");
+			if((retval=ub_ctx_hosts(ctx, buf)) !=0 ) {
+				snprintf(buf, sizeof(buf), "%s%s", name, 
+					"\\hosts");
+				retval=ub_ctx_hosts(ctx, buf);
+			}
+			free(name);
+			return retval;
+		}
+		return UB_READFILE;
+#else
+		fname = "/etc/hosts";
+#endif /* WIN32 */
+	}
+	in = fopen(fname, "r");
+	if(!in) {
+		/* error in errno! perror(fname) */
+		return UB_READFILE;
+	}
+	while(fgets(buf, (int)sizeof(buf), in)) {
+		buf[sizeof(buf)-1] = 0;
+		parse=buf;
+		while(*parse == ' ' || *parse == '\t')
+			parse++;
+		if(*parse == '#')
+			continue; /* skip comment */
+		/* format: <addr> spaces <name> spaces <name> ... */
+		addr = parse;
+		/* skip addr */
+		while(isxdigit(*parse) || *parse == '.' || *parse == ':')
+			parse++;
+		if(*parse == '\n' || *parse == 0)
+			continue;
+		if(*parse == '%') 
+			continue; /* ignore macOSX fe80::1%lo0 localhost */
+		if(*parse != ' ' && *parse != '\t') {
+			/* must have whitespace after address */
+			fclose(in);
+			errno=EINVAL;
+			return UB_SYNTAX;
+		}
+		*parse++ = 0; /* end delimiter for addr ... */
+		/* go to names and add them */
+		while(*parse) {
+			while(*parse == ' ' || *parse == '\t' || *parse=='\n')
+				parse++;
+			if(*parse == 0 || *parse == '#')
+				break;
+			/* skip name, allows (too) many printable characters */
+			name = parse;
+			while('!' <= *parse && *parse <= '~')
+				parse++;
+			if(*parse)
+				*parse++ = 0; /* end delimiter for name */
+			snprintf(ldata, sizeof(ldata), "%s %s %s",
+				name, str_is_ip6(addr)?"AAAA":"A", addr);
+			ins = strdup(ldata);
+			if(!ins) {
+				/* out of memory */
+				fclose(in);
+				errno=ENOMEM;
+				return UB_NOMEM;
+			}
+			lock_basic_lock(&ctx->cfglock);
+			if(!cfg_strlist_insert(&ctx->env->cfg->local_data, 
+				ins)) {
+				lock_basic_unlock(&ctx->cfglock);
+				fclose(in);
+				free(ins);
+				errno=ENOMEM;
+				return UB_NOMEM;
+			}
+			lock_basic_unlock(&ctx->cfglock);
+		}
+	}
+	fclose(in);
+	return UB_NOERROR;
+}
+
+/** finalize the context, if not already finalized */
+static int ub_ctx_finalize(struct ub_ctx* ctx)
+{
+	int res = 0;
+	lock_basic_lock(&ctx->cfglock);
+	if (!ctx->finalized) {
+		res = context_finalize(ctx);
+	}
+	lock_basic_unlock(&ctx->cfglock);
+	return res;
+}
+
+/* Print local zones and RR data */
+int ub_ctx_print_local_zones(struct ub_ctx* ctx)
+{   
+	int res = ub_ctx_finalize(ctx);
+	if (res) return res;
+
+	local_zones_print(ctx->local_zones);
+
+	return UB_NOERROR;
+}
+
+/* Add a new zone */
+int ub_ctx_zone_add(struct ub_ctx* ctx, const char *zone_name, 
+	const char *zone_type)
+{
+	enum localzone_type t;
+	struct local_zone* z;
+	uint8_t* nm;
+	int nmlabs;
+	size_t nmlen;
+
+	int res = ub_ctx_finalize(ctx);
+	if (res) return res;
+
+	if(!local_zone_str2type(zone_type, &t)) {
+		return UB_SYNTAX;
+	}
+
+	if(!parse_dname(zone_name, &nm, &nmlen, &nmlabs)) {
+		return UB_SYNTAX;
+	}
+
+	lock_rw_wrlock(&ctx->local_zones->lock);
+	if((z=local_zones_find(ctx->local_zones, nm, nmlen, nmlabs, 
+		LDNS_RR_CLASS_IN))) {
+		/* already present in tree */
+		lock_rw_wrlock(&z->lock);
+		z->type = t; /* update type anyway */
+		lock_rw_unlock(&z->lock);
+		lock_rw_unlock(&ctx->local_zones->lock);
+		free(nm);
+		return UB_NOERROR;
+	}
+	if(!local_zones_add_zone(ctx->local_zones, nm, nmlen, nmlabs, 
+		LDNS_RR_CLASS_IN, t)) {
+		lock_rw_unlock(&ctx->local_zones->lock);
+		return UB_NOMEM;
+	}
+	lock_rw_unlock(&ctx->local_zones->lock);
+	return UB_NOERROR;
+}
+
+/* Remove zone */
+int ub_ctx_zone_remove(struct ub_ctx* ctx, const char *zone_name)
+{   
+	struct local_zone* z;
+	uint8_t* nm;
+	int nmlabs;
+	size_t nmlen;
+
+	int res = ub_ctx_finalize(ctx);
+	if (res) return res;
+
+	if(!parse_dname(zone_name, &nm, &nmlen, &nmlabs)) {
+		return UB_SYNTAX;
+	}
+
+	lock_rw_wrlock(&ctx->local_zones->lock);
+	if((z=local_zones_find(ctx->local_zones, nm, nmlen, nmlabs, 
+		LDNS_RR_CLASS_IN))) {
+		/* present in tree */
+		local_zones_del_zone(ctx->local_zones, z);
+	}
+	lock_rw_unlock(&ctx->local_zones->lock);
+	free(nm);
+	return UB_NOERROR;
+}
+
+/* Add new RR data */
+int ub_ctx_data_add(struct ub_ctx* ctx, const char *data)
+{
+	int res = ub_ctx_finalize(ctx);
+	if (res) return res;
+
+	res = local_zones_add_RR(ctx->local_zones, data);
+	return (!res) ? UB_NOMEM : UB_NOERROR;
+}
+
+/* Remove RR data */
+int ub_ctx_data_remove(struct ub_ctx* ctx, const char *data)
+{
+	uint8_t* nm;
+	int nmlabs;
+	size_t nmlen;
+	int res = ub_ctx_finalize(ctx);
+	if (res) return res;
+
+	if(!parse_dname(data, &nm, &nmlen, &nmlabs)) 
+		return UB_SYNTAX;
+
+	local_zones_del_data(ctx->local_zones, nm, nmlen, nmlabs, 
+		LDNS_RR_CLASS_IN);
+
+	free(nm);
+	return UB_NOERROR;
+}
+
+const char* ub_version(void)
+{
+	return PACKAGE_VERSION;
+}
+
+int 
+ub_ctx_set_event(struct ub_ctx* ctx, struct event_base* base) {
+	if (!ctx || !ctx->event_base || !base) {
+		return UB_INITFAIL;
+	}
+	if (ctx->event_base == base) {
+		/* already set */
+		return UB_NOERROR;
+	}
+	
+	lock_basic_lock(&ctx->cfglock);
+	/* destroy the current worker - safe to pass in NULL */
+	libworker_delete_event(ctx->event_worker);
+	ctx->event_worker = NULL;
+	ctx->event_base = base;	
+	ctx->created_bg = 0;
+	ctx->dothread = 1;
+	lock_basic_unlock(&ctx->cfglock);
+	return UB_NOERROR;
+}