1 files changed, 1186 insertions, 0 deletions
diff --git a/3rdParty/Unbound/src/src/services/mesh.c b/3rdParty/Unbound/src/src/services/mesh.c
new file mode 100644
index 0000000..f6fd288
--- /dev/null
+++ b/3rdParty/Unbound/src/src/services/mesh.c
@@ -0,0 +1,1186 @@
+/*
+ * services/mesh.c - deal with mesh of query states and handle events for that.
+ *
+ * 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 REGENTS 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 assist in dealing with a mesh of
+ * query states. This mesh is supposed to be thread-specific.
+ * It consists of query states (per qname, qtype, qclass) and connections
+ * between query states and the super and subquery states, and replies to
+ * send back to clients.
+ */
+#include "config.h"
+#include <ldns/wire2host.h>
+#include "services/mesh.h"
+#include "services/outbound_list.h"
+#include "services/cache/dns.h"
+#include "util/log.h"
+#include "util/net_help.h"
+#include "util/module.h"
+#include "util/regional.h"
+#include "util/data/msgencode.h"
+#include "util/timehist.h"
+#include "util/fptr_wlist.h"
+#include "util/alloc.h"
+#include "util/config_file.h"
+
+/** subtract timers and the values do not overflow or become negative */
+static void
+timeval_subtract(struct timeval* d, const struct timeval* end, const struct timeval* start)
+{
+#ifndef S_SPLINT_S
+	time_t end_usec = end->tv_usec;
+	d->tv_sec = end->tv_sec - start->tv_sec;
+	if(end_usec < start->tv_usec) {
+		end_usec += 1000000;
+		d->tv_sec--;
+	}
+	d->tv_usec = end_usec - start->tv_usec;
+#endif
+}
+
+/** add timers and the values do not overflow or become negative */
+static void
+timeval_add(struct timeval* d, const struct timeval* add)
+{
+#ifndef S_SPLINT_S
+	d->tv_sec += add->tv_sec;
+	d->tv_usec += add->tv_usec;
+	if(d->tv_usec > 1000000 ) {
+		d->tv_usec -= 1000000;
+		d->tv_sec++;
+	}
+#endif
+}
+
+/** divide sum of timers to get average */
+static void
+timeval_divide(struct timeval* avg, const struct timeval* sum, size_t d)
+{
+#ifndef S_SPLINT_S
+	size_t leftover;
+	if(d == 0) {
+		avg->tv_sec = 0;
+		avg->tv_usec = 0;
+		return;
+	}
+	avg->tv_sec = sum->tv_sec / d;
+	avg->tv_usec = sum->tv_usec / d;
+	/* handle fraction from seconds divide */
+	leftover = sum->tv_sec - avg->tv_sec*d;
+	avg->tv_usec += (leftover*1000000)/d;
+#endif
+}
+
+/** histogram compare of time values */
+static int
+timeval_smaller(const struct timeval* x, const struct timeval* y)
+{
+#ifndef S_SPLINT_S
+	if(x->tv_sec < y->tv_sec)
+		return 1;
+	else if(x->tv_sec == y->tv_sec) {
+		if(x->tv_usec <= y->tv_usec)
+			return 1;
+		else	return 0;
+	}
+	else	return 0;
+#endif
+}
+
+int
+mesh_state_compare(const void* ap, const void* bp)
+{
+	struct mesh_state* a = (struct mesh_state*)ap;
+	struct mesh_state* b = (struct mesh_state*)bp;
+
+	if(a->s.is_priming && !b->s.is_priming)
+		return -1;
+	if(!a->s.is_priming && b->s.is_priming)
+		return 1;
+
+	if((a->s.query_flags&BIT_RD) && !(b->s.query_flags&BIT_RD))
+		return -1;
+	if(!(a->s.query_flags&BIT_RD) && (b->s.query_flags&BIT_RD))
+		return 1;
+
+	if((a->s.query_flags&BIT_CD) && !(b->s.query_flags&BIT_CD))
+		return -1;
+	if(!(a->s.query_flags&BIT_CD) && (b->s.query_flags&BIT_CD))
+		return 1;
+
+	return query_info_compare(&a->s.qinfo, &b->s.qinfo);
+}
+
+int
+mesh_state_ref_compare(const void* ap, const void* bp)
+{
+	struct mesh_state_ref* a = (struct mesh_state_ref*)ap;
+	struct mesh_state_ref* b = (struct mesh_state_ref*)bp;
+	return mesh_state_compare(a->s, b->s);
+}
+
+struct mesh_area* 
+mesh_create(struct module_stack* stack, struct module_env* env)
+{
+	struct mesh_area* mesh = calloc(1, sizeof(struct mesh_area));
+	if(!mesh) {
+		log_err("mesh area alloc: out of memory");
+		return NULL;
+	}
+	mesh->histogram = timehist_setup();
+	mesh->qbuf_bak = ldns_buffer_new(env->cfg->msg_buffer_size);
+	if(!mesh->histogram || !mesh->qbuf_bak) {
+		free(mesh);
+		log_err("mesh area alloc: out of memory");
+		return NULL;
+	}
+	mesh->mods = *stack;
+	mesh->env = env;
+	rbtree_init(&mesh->run, &mesh_state_compare);
+	rbtree_init(&mesh->all, &mesh_state_compare);
+	mesh->num_reply_addrs = 0;
+	mesh->num_reply_states = 0;
+	mesh->num_detached_states = 0;
+	mesh->num_forever_states = 0;
+	mesh->stats_jostled = 0;
+	mesh->stats_dropped = 0;
+	mesh->max_reply_states = env->cfg->num_queries_per_thread;
+	mesh->max_forever_states = (mesh->max_reply_states+1)/2;
+#ifndef S_SPLINT_S
+	mesh->jostle_max.tv_sec = (time_t)(env->cfg->jostle_time / 1000);
+	mesh->jostle_max.tv_usec = (time_t)((env->cfg->jostle_time % 1000)
+		*1000);
+#endif
+	return mesh;
+}
+
+/** help mesh delete delete mesh states */
+static void
+mesh_delete_helper(rbnode_t* n)
+{
+	struct mesh_state* mstate = (struct mesh_state*)n->key;
+	/* perform a full delete, not only 'cleanup' routine,
+	 * because other callbacks expect a clean state in the mesh.
+	 * For 're-entrant' calls */
+	mesh_state_delete(&mstate->s);
+	/* but because these delete the items from the tree, postorder
+	 * traversal and rbtree rebalancing do not work together */
+}
+
+void 
+mesh_delete(struct mesh_area* mesh)
+{
+	if(!mesh)
+		return;
+	/* free all query states */
+	while(mesh->all.count)
+		mesh_delete_helper(mesh->all.root);
+	timehist_delete(mesh->histogram);
+	ldns_buffer_free(mesh->qbuf_bak);
+	free(mesh);
+}
+
+void
+mesh_delete_all(struct mesh_area* mesh)
+{
+	/* free all query states */
+	while(mesh->all.count)
+		mesh_delete_helper(mesh->all.root);
+	mesh->stats_dropped += mesh->num_reply_addrs;
+	/* clear mesh area references */
+	rbtree_init(&mesh->run, &mesh_state_compare);
+	rbtree_init(&mesh->all, &mesh_state_compare);
+	mesh->num_reply_addrs = 0;
+	mesh->num_reply_states = 0;
+	mesh->num_detached_states = 0;
+	mesh->num_forever_states = 0;
+	mesh->forever_first = NULL;
+	mesh->forever_last = NULL;
+	mesh->jostle_first = NULL;
+	mesh->jostle_last = NULL;
+}
+
+int mesh_make_new_space(struct mesh_area* mesh, ldns_buffer* qbuf)
+{
+	struct mesh_state* m = mesh->jostle_first;
+	/* free space is available */
+	if(mesh->num_reply_states < mesh->max_reply_states)
+		return 1;
+	/* try to kick out a jostle-list item */
+	if(m && m->reply_list && m->list_select == mesh_jostle_list) {
+		/* how old is it? */
+		struct timeval age;
+		timeval_subtract(&age, mesh->env->now_tv, 
+			&m->reply_list->start_time);
+		if(timeval_smaller(&mesh->jostle_max, &age)) {
+			/* its a goner */
+			log_nametypeclass(VERB_ALGO, "query jostled out to "
+				"make space for a new one",
+				m->s.qinfo.qname, m->s.qinfo.qtype,
+				m->s.qinfo.qclass);
+			/* backup the query */
+			if(qbuf) ldns_buffer_copy(mesh->qbuf_bak, qbuf);
+			/* notify supers */
+			if(m->super_set.count > 0) {
+				verbose(VERB_ALGO, "notify supers of failure");
+				m->s.return_msg = NULL;
+				m->s.return_rcode = LDNS_RCODE_SERVFAIL;
+				mesh_walk_supers(mesh, m);
+			}
+			mesh->stats_jostled ++;
+			mesh_state_delete(&m->s);
+			/* restore the query - note that the qinfo ptr to
+			 * the querybuffer is then correct again. */
+			if(qbuf) ldns_buffer_copy(qbuf, mesh->qbuf_bak);
+			return 1;
+		}
+	}
+	/* no space for new item */
+	return 0;
+}
+
+void mesh_new_client(struct mesh_area* mesh, struct query_info* qinfo,
+        uint16_t qflags, struct edns_data* edns, struct comm_reply* rep,
+        uint16_t qid)
+{
+	/* do not use CD flag from user for mesh state, we want the CD-query
+	 * to receive validation anyway, to protect out cache contents and
+	 * avoid bad-data in this cache that a downstream validator cannot
+	 * remove from this cache */
+	struct mesh_state* s = mesh_area_find(mesh, qinfo, qflags&BIT_RD, 0);
+	int was_detached = 0;
+	int was_noreply = 0;
+	int added = 0;
+	/* does this create a new reply state? */
+	if(!s || s->list_select == mesh_no_list) {
+		if(!mesh_make_new_space(mesh, rep->c->buffer)) {
+			verbose(VERB_ALGO, "Too many queries. dropping "
+				"incoming query.");
+			comm_point_drop_reply(rep);
+			mesh->stats_dropped ++;
+			return;
+		}
+		/* for this new reply state, the reply address is free,
+		 * so the limit of reply addresses does not stop reply states*/
+	} else {
+		/* protect our memory usage from storing reply addresses */
+		if(mesh->num_reply_addrs > mesh->max_reply_states*16) {
+			verbose(VERB_ALGO, "Too many requests queued. "
+				"dropping incoming query.");
+			mesh->stats_dropped++;
+			comm_point_drop_reply(rep);
+			return;
+		}
+	}
+	/* see if it already exists, if not, create one */
+	if(!s) {
+#ifdef UNBOUND_DEBUG
+		struct rbnode_t* n;
+#endif
+		s = mesh_state_create(mesh->env, qinfo, qflags&BIT_RD, 0);
+		if(!s) {
+			log_err("mesh_state_create: out of memory; SERVFAIL");
+			error_encode(rep->c->buffer, LDNS_RCODE_SERVFAIL,
+				qinfo, qid, qflags, edns);
+			comm_point_send_reply(rep);
+			return;
+		}
+#ifdef UNBOUND_DEBUG
+		n =
+#endif
+		rbtree_insert(&mesh->all, &s->node);
+		log_assert(n != NULL);
+		/* set detached (it is now) */
+		mesh->num_detached_states++;
+		added = 1;
+	}
+	if(!s->reply_list && !s->cb_list && s->super_set.count == 0)
+		was_detached = 1;
+	if(!s->reply_list && !s->cb_list)
+		was_noreply = 1;
+	/* add reply to s */
+	if(!mesh_state_add_reply(s, edns, rep, qid, qflags, qinfo->qname)) {
+			log_err("mesh_new_client: out of memory; SERVFAIL");
+			error_encode(rep->c->buffer, LDNS_RCODE_SERVFAIL,
+				qinfo, qid, qflags, edns);
+			comm_point_send_reply(rep);
+			if(added)
+				mesh_state_delete(&s->s);
+			return;
+	}
+	/* update statistics */
+	if(was_detached) {
+		log_assert(mesh->num_detached_states > 0);
+		mesh->num_detached_states--;
+	}
+	if(was_noreply) {
+		mesh->num_reply_states ++;
+	}
+	mesh->num_reply_addrs++;
+	if(s->list_select == mesh_no_list) {
+		/* move to either the forever or the jostle_list */
+		if(mesh->num_forever_states < mesh->max_forever_states) {
+			mesh->num_forever_states ++;
+			mesh_list_insert(s, &mesh->forever_first, 
+				&mesh->forever_last);
+			s->list_select = mesh_forever_list;
+		} else {
+			mesh_list_insert(s, &mesh->jostle_first, 
+				&mesh->jostle_last);
+			s->list_select = mesh_jostle_list;
+		}
+	}
+	if(added)
+		mesh_run(mesh, s, module_event_new, NULL);
+}
+
+int 
+mesh_new_callback(struct mesh_area* mesh, struct query_info* qinfo,
+	uint16_t qflags, struct edns_data* edns, ldns_buffer* buf, 
+	uint16_t qid, mesh_cb_func_t cb, void* cb_arg)
+{
+	struct mesh_state* s = mesh_area_find(mesh, qinfo, qflags&BIT_RD, 0);
+	int was_detached = 0;
+	int was_noreply = 0;
+	int added = 0;
+	/* there are no limits on the number of callbacks */
+
+	/* see if it already exists, if not, create one */
+	if(!s) {
+#ifdef UNBOUND_DEBUG
+		struct rbnode_t* n;
+#endif
+		s = mesh_state_create(mesh->env, qinfo, qflags&BIT_RD, 0);
+		if(!s) {
+			return 0;
+		}
+#ifdef UNBOUND_DEBUG
+		n =
+#endif
+		rbtree_insert(&mesh->all, &s->node);
+		log_assert(n != NULL);
+		/* set detached (it is now) */
+		mesh->num_detached_states++;
+		added = 1;
+	}
+	if(!s->reply_list && !s->cb_list && s->super_set.count == 0)
+		was_detached = 1;
+	if(!s->reply_list && !s->cb_list)
+		was_noreply = 1;
+	/* add reply to s */
+	if(!mesh_state_add_cb(s, edns, buf, cb, cb_arg, qid, qflags)) {
+			if(added)
+				mesh_state_delete(&s->s);
+			return 0;
+	}
+	/* update statistics */
+	if(was_detached) {
+		log_assert(mesh->num_detached_states > 0);
+		mesh->num_detached_states--;
+	}
+	if(was_noreply) {
+		mesh->num_reply_states ++;
+	}
+	mesh->num_reply_addrs++;
+	if(added)
+		mesh_run(mesh, s, module_event_new, NULL);
+	return 1;
+}
+
+void mesh_new_prefetch(struct mesh_area* mesh, struct query_info* qinfo,
+        uint16_t qflags, uint32_t leeway)
+{
+	struct mesh_state* s = mesh_area_find(mesh, qinfo, qflags&BIT_RD, 0);
+#ifdef UNBOUND_DEBUG
+	struct rbnode_t* n;
+#endif
+	/* already exists, and for a different purpose perhaps.
+	 * if mesh_no_list, keep it that way. */
+	if(s) {
+		/* make it ignore the cache from now on */
+		if(!s->s.blacklist)
+			sock_list_insert(&s->s.blacklist, NULL, 0, s->s.region);
+		if(s->s.prefetch_leeway < leeway)
+			s->s.prefetch_leeway = leeway;
+		return;
+	}
+	if(!mesh_make_new_space(mesh, NULL)) {
+		verbose(VERB_ALGO, "Too many queries. dropped prefetch.");
+		mesh->stats_dropped ++;
+		return;
+	}
+	s = mesh_state_create(mesh->env, qinfo, qflags&BIT_RD, 0);
+	if(!s) {
+		log_err("prefetch mesh_state_create: out of memory");
+		return;
+	}
+#ifdef UNBOUND_DEBUG
+	n =
+#endif
+	rbtree_insert(&mesh->all, &s->node);
+	log_assert(n != NULL);
+	/* set detached (it is now) */
+	mesh->num_detached_states++;
+	/* make it ignore the cache */
+	sock_list_insert(&s->s.blacklist, NULL, 0, s->s.region);
+	s->s.prefetch_leeway = leeway;
+
+	if(s->list_select == mesh_no_list) {
+		/* move to either the forever or the jostle_list */
+		if(mesh->num_forever_states < mesh->max_forever_states) {
+			mesh->num_forever_states ++;
+			mesh_list_insert(s, &mesh->forever_first, 
+				&mesh->forever_last);
+			s->list_select = mesh_forever_list;
+		} else {
+			mesh_list_insert(s, &mesh->jostle_first, 
+				&mesh->jostle_last);
+			s->list_select = mesh_jostle_list;
+		}
+	}
+	mesh_run(mesh, s, module_event_new, NULL);
+}
+
+void mesh_report_reply(struct mesh_area* mesh, struct outbound_entry* e,
+        struct comm_reply* reply, int what)
+{
+	enum module_ev event = module_event_reply;
+	e->qstate->reply = reply;
+	if(what != NETEVENT_NOERROR) {
+		event = module_event_noreply;
+		if(what == NETEVENT_CAPSFAIL)
+			event = module_event_capsfail;
+	}
+	mesh_run(mesh, e->qstate->mesh_info, event, e);
+}
+
+struct mesh_state* 
+mesh_state_create(struct module_env* env, struct query_info* qinfo, 
+	uint16_t qflags, int prime)
+{
+	struct regional* region = alloc_reg_obtain(env->alloc);
+	struct mesh_state* mstate;
+	int i;
+	if(!region)
+		return NULL;
+	mstate = (struct mesh_state*)regional_alloc(region, 
+		sizeof(struct mesh_state));
+	if(!mstate) {
+		alloc_reg_release(env->alloc, region);
+		return NULL;
+	}
+	memset(mstate, 0, sizeof(*mstate));
+	mstate->node = *RBTREE_NULL;
+	mstate->run_node = *RBTREE_NULL;
+	mstate->node.key = mstate;
+	mstate->run_node.key = mstate;
+	mstate->reply_list = NULL;
+	mstate->list_select = mesh_no_list;
+	mstate->replies_sent = 0;
+	rbtree_init(&mstate->super_set, &mesh_state_ref_compare);
+	rbtree_init(&mstate->sub_set, &mesh_state_ref_compare);
+	mstate->num_activated = 0;
+	/* init module qstate */
+	mstate->s.qinfo.qtype = qinfo->qtype;
+	mstate->s.qinfo.qclass = qinfo->qclass;
+	mstate->s.qinfo.qname_len = qinfo->qname_len;
+	mstate->s.qinfo.qname = regional_alloc_init(region, qinfo->qname,
+		qinfo->qname_len);
+	if(!mstate->s.qinfo.qname) {
+		alloc_reg_release(env->alloc, region);
+		return NULL;
+	}
+	/* remove all weird bits from qflags */
+	mstate->s.query_flags = (qflags & (BIT_RD|BIT_CD));
+	mstate->s.is_priming = prime;
+	mstate->s.reply = NULL;
+	mstate->s.region = region;
+	mstate->s.curmod = 0;
+	mstate->s.return_msg = 0;
+	mstate->s.return_rcode = LDNS_RCODE_NOERROR;
+	mstate->s.env = env;
+	mstate->s.mesh_info = mstate;
+	mstate->s.prefetch_leeway = 0;
+	/* init modules */
+	for(i=0; i<env->mesh->mods.num; i++) {
+		mstate->s.minfo[i] = NULL;
+		mstate->s.ext_state[i] = module_state_initial;
+	}
+	return mstate;
+}
+
+void 
+mesh_state_cleanup(struct mesh_state* mstate)
+{
+	struct mesh_area* mesh;
+	int i;
+	if(!mstate)
+		return;
+	mesh = mstate->s.env->mesh;
+	/* drop unsent replies */
+	if(!mstate->replies_sent) {
+		struct mesh_reply* rep;
+		struct mesh_cb* cb;
+		for(rep=mstate->reply_list; rep; rep=rep->next) {
+			comm_point_drop_reply(&rep->query_reply);
+			mesh->num_reply_addrs--;
+		}
+		for(cb=mstate->cb_list; cb; cb=cb->next) {
+			fptr_ok(fptr_whitelist_mesh_cb(cb->cb));
+			(*cb->cb)(cb->cb_arg, LDNS_RCODE_SERVFAIL, NULL,
+				sec_status_unchecked, NULL);
+			mesh->num_reply_addrs--;
+		}
+	}
+
+	/* de-init modules */
+	for(i=0; i<mesh->mods.num; i++) {
+		fptr_ok(fptr_whitelist_mod_clear(mesh->mods.mod[i]->clear));
+		(*mesh->mods.mod[i]->clear)(&mstate->s, i);
+		mstate->s.minfo[i] = NULL;
+		mstate->s.ext_state[i] = module_finished;
+	}
+	alloc_reg_release(mstate->s.env->alloc, mstate->s.region);
+}
+
+void 
+mesh_state_delete(struct module_qstate* qstate)
+{
+	struct mesh_area* mesh;
+	struct mesh_state_ref* super, ref;
+	struct mesh_state* mstate;
+	if(!qstate)
+		return;
+	mstate = qstate->mesh_info;
+	mesh = mstate->s.env->mesh;
+	mesh_detach_subs(&mstate->s);
+	if(mstate->list_select == mesh_forever_list) {
+		mesh->num_forever_states --;
+		mesh_list_remove(mstate, &mesh->forever_first, 
+			&mesh->forever_last);
+	} else if(mstate->list_select == mesh_jostle_list) {
+		mesh_list_remove(mstate, &mesh->jostle_first, 
+			&mesh->jostle_last);
+	}
+	if(!mstate->reply_list && !mstate->cb_list
+		&& mstate->super_set.count == 0) {
+		log_assert(mesh->num_detached_states > 0);
+		mesh->num_detached_states--;
+	}
+	if(mstate->reply_list || mstate->cb_list) {
+		log_assert(mesh->num_reply_states > 0);
+		mesh->num_reply_states--;
+	}
+	ref.node.key = &ref;
+	ref.s = mstate;
+	RBTREE_FOR(super, struct mesh_state_ref*, &mstate->super_set) {
+		(void)rbtree_delete(&super->s->sub_set, &ref);
+	}
+	(void)rbtree_delete(&mesh->run, mstate);
+	(void)rbtree_delete(&mesh->all, mstate);
+	mesh_state_cleanup(mstate);
+}
+
+/** helper recursive rbtree find routine */
+static int
+find_in_subsub(struct mesh_state* m, struct mesh_state* tofind, size_t *c)
+{
+	struct mesh_state_ref* r;
+	if((*c)++ > MESH_MAX_SUBSUB)
+		return 1;
+	RBTREE_FOR(r, struct mesh_state_ref*, &m->sub_set) {
+		if(r->s == tofind || find_in_subsub(r->s, tofind, c))
+			return 1;
+	}
+	return 0;
+}
+
+/** find cycle for already looked up mesh_state */
+static int 
+mesh_detect_cycle_found(struct module_qstate* qstate, struct mesh_state* dep_m)
+{
+	struct mesh_state* cyc_m = qstate->mesh_info;
+	size_t counter = 0;
+	if(!dep_m)
+		return 0;
+	if(dep_m == cyc_m || find_in_subsub(dep_m, cyc_m, &counter)) {
+		if(counter > MESH_MAX_SUBSUB)
+			return 2;
+		return 1;
+	}
+	return 0;
+}
+
+void mesh_detach_subs(struct module_qstate* qstate)
+{
+	struct mesh_area* mesh = qstate->env->mesh;
+	struct mesh_state_ref* ref, lookup;
+#ifdef UNBOUND_DEBUG
+	struct rbnode_t* n;
+#endif
+	lookup.node.key = &lookup;
+	lookup.s = qstate->mesh_info;
+	RBTREE_FOR(ref, struct mesh_state_ref*, &qstate->mesh_info->sub_set) {
+#ifdef UNBOUND_DEBUG
+		n =
+#endif
+		rbtree_delete(&ref->s->super_set, &lookup);
+		log_assert(n != NULL); /* must have been present */
+		if(!ref->s->reply_list && !ref->s->cb_list
+			&& ref->s->super_set.count == 0) {
+			mesh->num_detached_states++;
+			log_assert(mesh->num_detached_states + 
+				mesh->num_reply_states <= mesh->all.count);
+		}
+	}
+	rbtree_init(&qstate->mesh_info->sub_set, &mesh_state_ref_compare);
+}
+
+int mesh_attach_sub(struct module_qstate* qstate, struct query_info* qinfo,
+        uint16_t qflags, int prime, struct module_qstate** newq)
+{
+	/* find it, if not, create it */
+	struct mesh_area* mesh = qstate->env->mesh;
+	struct mesh_state* sub = mesh_area_find(mesh, qinfo, qflags, prime);
+	if(mesh_detect_cycle_found(qstate, sub)) {
+		verbose(VERB_ALGO, "attach failed, cycle detected");
+		return 0;
+	}
+	if(!sub) {
+#ifdef UNBOUND_DEBUG
+		struct rbnode_t* n;
+#endif
+		/* create a new one */
+		sub = mesh_state_create(qstate->env, qinfo, qflags, prime);
+		if(!sub) {
+			log_err("mesh_attach_sub: out of memory");
+			return 0;
+		}
+#ifdef UNBOUND_DEBUG
+		n =
+#endif
+		rbtree_insert(&mesh->all, &sub->node);
+		log_assert(n != NULL);
+		/* set detached (it is now) */
+		mesh->num_detached_states++;
+		/* set new query state to run */
+#ifdef UNBOUND_DEBUG
+		n =
+#endif
+		rbtree_insert(&mesh->run, &sub->run_node);
+		log_assert(n != NULL);
+		*newq = &sub->s;
+	} else
+		*newq = NULL;
+	if(!mesh_state_attachment(qstate->mesh_info, sub))
+		return 0;
+	if(!sub->reply_list && !sub->cb_list && sub->super_set.count == 1) {
+		/* it used to be detached, before this one got added */
+		log_assert(mesh->num_detached_states > 0);
+		mesh->num_detached_states--;
+	}
+	/* *newq will be run when inited after the current module stops */
+	return 1;
+}
+
+int mesh_state_attachment(struct mesh_state* super, struct mesh_state* sub)
+{
+#ifdef UNBOUND_DEBUG
+	struct rbnode_t* n;
+#endif
+	struct mesh_state_ref* subref; /* points to sub, inserted in super */
+	struct mesh_state_ref* superref; /* points to super, inserted in sub */
+	if( !(subref = regional_alloc(super->s.region,
+		sizeof(struct mesh_state_ref))) ||
+		!(superref = regional_alloc(sub->s.region,
+		sizeof(struct mesh_state_ref))) ) {
+		log_err("mesh_state_attachment: out of memory");
+		return 0;
+	}
+	superref->node.key = superref;
+	superref->s = super;
+	subref->node.key = subref;
+	subref->s = sub;
+#ifdef UNBOUND_DEBUG
+	n =
+#endif
+	rbtree_insert(&sub->super_set, &superref->node);
+	log_assert(n != NULL);
+#ifdef UNBOUND_DEBUG
+	n =
+#endif
+	rbtree_insert(&super->sub_set, &subref->node);
+	log_assert(n != NULL);
+	return 1;
+}
+
+/**
+ * callback results to mesh cb entry
+ * @param m: mesh state to send it for.
+ * @param rcode: if not 0, error code.
+ * @param rep: reply to send (or NULL if rcode is set).
+ * @param r: callback entry
+ */
+static void
+mesh_do_callback(struct mesh_state* m, int rcode, struct reply_info* rep,
+	struct mesh_cb* r)
+{
+	int secure;
+	char* reason = NULL;
+	/* bogus messages are not made into servfail, sec_status passed 
+	 * to the callback function */
+	if(rep && rep->security == sec_status_secure)
+		secure = 1;
+	else	secure = 0;
+	if(!rep && rcode == LDNS_RCODE_NOERROR)
+		rcode = LDNS_RCODE_SERVFAIL;
+	if(!rcode && rep->security == sec_status_bogus) {
+		if(!(reason = errinf_to_str(&m->s)))
+			rcode = LDNS_RCODE_SERVFAIL;
+	}
+	/* send the reply */
+	if(rcode) {
+		fptr_ok(fptr_whitelist_mesh_cb(r->cb));
+		(*r->cb)(r->cb_arg, rcode, r->buf, sec_status_unchecked, NULL);
+	} else {
+		size_t udp_size = r->edns.udp_size;
+		ldns_buffer_clear(r->buf);
+		r->edns.edns_version = EDNS_ADVERTISED_VERSION;
+		r->edns.udp_size = EDNS_ADVERTISED_SIZE;
+		r->edns.ext_rcode = 0;
+		r->edns.bits &= EDNS_DO;
+		if(!reply_info_answer_encode(&m->s.qinfo, rep, r->qid, 
+			r->qflags, r->buf, 0, 1, 
+			m->s.env->scratch, udp_size, &r->edns, 
+			(int)(r->edns.bits & EDNS_DO), secure)) 
+		{
+			fptr_ok(fptr_whitelist_mesh_cb(r->cb));
+			(*r->cb)(r->cb_arg, LDNS_RCODE_SERVFAIL, r->buf,
+				sec_status_unchecked, NULL);
+		} else {
+			fptr_ok(fptr_whitelist_mesh_cb(r->cb));
+			(*r->cb)(r->cb_arg, LDNS_RCODE_NOERROR, r->buf,
+				rep->security, reason);
+		}
+	}
+	free(reason);
+	m->s.env->mesh->num_reply_addrs--;
+}
+
+/**
+ * Send reply to mesh reply entry
+ * @param m: mesh state to send it for.
+ * @param rcode: if not 0, error code.
+ * @param rep: reply to send (or NULL if rcode is set).
+ * @param r: reply entry
+ * @param prev: previous reply, already has its answer encoded in buffer.
+ */
+static void
+mesh_send_reply(struct mesh_state* m, int rcode, struct reply_info* rep,
+	struct mesh_reply* r, struct mesh_reply* prev)
+{
+	struct timeval end_time;
+	struct timeval duration;
+	int secure;
+	/* examine security status */
+	if(m->s.env->need_to_validate && (!(r->qflags&BIT_CD) ||
+		m->s.env->cfg->ignore_cd) && rep && 
+		rep->security <= sec_status_bogus) {
+		rcode = LDNS_RCODE_SERVFAIL;
+		if(m->s.env->cfg->stat_extended) 
+			m->s.env->mesh->ans_bogus++;
+	}
+	if(rep && rep->security == sec_status_secure)
+		secure = 1;
+	else	secure = 0;
+	if(!rep && rcode == LDNS_RCODE_NOERROR)
+		rcode = LDNS_RCODE_SERVFAIL;
+	/* send the reply */
+	if(prev && prev->qflags == r->qflags && 
+		prev->edns.edns_present == r->edns.edns_present && 
+		prev->edns.bits == r->edns.bits && 
+		prev->edns.udp_size == r->edns.udp_size) {
+		/* if the previous reply is identical to this one, fix ID */
+		if(prev->query_reply.c->buffer != r->query_reply.c->buffer)
+			ldns_buffer_copy(r->query_reply.c->buffer, 
+				prev->query_reply.c->buffer);
+		ldns_buffer_write_at(r->query_reply.c->buffer, 0, 
+			&r->qid, sizeof(uint16_t));
+		ldns_buffer_write_at(r->query_reply.c->buffer, 12, 
+			r->qname, m->s.qinfo.qname_len);
+		comm_point_send_reply(&r->query_reply);
+	} else if(rcode) {
+		m->s.qinfo.qname = r->qname;
+		error_encode(r->query_reply.c->buffer, rcode, &m->s.qinfo,
+			r->qid, r->qflags, &r->edns);
+		comm_point_send_reply(&r->query_reply);
+	} else {
+		size_t udp_size = r->edns.udp_size;
+		r->edns.edns_version = EDNS_ADVERTISED_VERSION;
+		r->edns.udp_size = EDNS_ADVERTISED_SIZE;
+		r->edns.ext_rcode = 0;
+		r->edns.bits &= EDNS_DO;
+		m->s.qinfo.qname = r->qname;
+		if(!reply_info_answer_encode(&m->s.qinfo, rep, r->qid, 
+			r->qflags, r->query_reply.c->buffer, 0, 1, 
+			m->s.env->scratch, udp_size, &r->edns, 
+			(int)(r->edns.bits & EDNS_DO), secure)) 
+		{
+			error_encode(r->query_reply.c->buffer, 
+				LDNS_RCODE_SERVFAIL, &m->s.qinfo, r->qid, 
+				r->qflags, &r->edns);
+		}
+		comm_point_send_reply(&r->query_reply);
+	}
+	/* account */
+	m->s.env->mesh->num_reply_addrs--;
+	end_time = *m->s.env->now_tv;
+	timeval_subtract(&duration, &end_time, &r->start_time);
+	verbose(VERB_ALGO, "query took %d.%6.6d sec",
+		(int)duration.tv_sec, (int)duration.tv_usec);
+	m->s.env->mesh->replies_sent++;
+	timeval_add(&m->s.env->mesh->replies_sum_wait, &duration);
+	timehist_insert(m->s.env->mesh->histogram, &duration);
+	if(m->s.env->cfg->stat_extended) {
+		uint16_t rc = FLAGS_GET_RCODE(ldns_buffer_read_u16_at(r->
+			query_reply.c->buffer, 2));
+		if(secure) m->s.env->mesh->ans_secure++;
+		m->s.env->mesh->ans_rcode[ rc ] ++;
+		if(rc == 0 && LDNS_ANCOUNT(ldns_buffer_begin(r->
+			query_reply.c->buffer)) == 0)
+			m->s.env->mesh->ans_nodata++;
+	}
+}
+
+void mesh_query_done(struct mesh_state* mstate)
+{
+	struct mesh_reply* r;
+	struct mesh_reply* prev = NULL;
+	struct mesh_cb* c;
+	struct reply_info* rep = (mstate->s.return_msg?
+		mstate->s.return_msg->rep:NULL);
+	for(r = mstate->reply_list; r; r = r->next) {
+		mesh_send_reply(mstate, mstate->s.return_rcode, rep, r, prev);
+		prev = r;
+	}
+	mstate->replies_sent = 1;
+	for(c = mstate->cb_list; c; c = c->next) {
+		mesh_do_callback(mstate, mstate->s.return_rcode, rep, c);
+	}
+}
+
+void mesh_walk_supers(struct mesh_area* mesh, struct mesh_state* mstate)
+{
+	struct mesh_state_ref* ref;
+	RBTREE_FOR(ref, struct mesh_state_ref*, &mstate->super_set)
+	{
+		/* make super runnable */
+		(void)rbtree_insert(&mesh->run, &ref->s->run_node);
+		/* callback the function to inform super of result */
+		fptr_ok(fptr_whitelist_mod_inform_super(
+			mesh->mods.mod[ref->s->s.curmod]->inform_super));
+		(*mesh->mods.mod[ref->s->s.curmod]->inform_super)(&mstate->s, 
+			ref->s->s.curmod, &ref->s->s);
+	}
+}
+
+struct mesh_state* mesh_area_find(struct mesh_area* mesh,
+	struct query_info* qinfo, uint16_t qflags, int prime)
+{
+	struct mesh_state key;
+	struct mesh_state* result;
+
+	key.node.key = &key;
+	key.s.is_priming = prime;
+	key.s.qinfo = *qinfo;
+	key.s.query_flags = qflags;
+	
+	result = (struct mesh_state*)rbtree_search(&mesh->all, &key);
+	return result;
+}
+
+int mesh_state_add_cb(struct mesh_state* s, struct edns_data* edns,
+        ldns_buffer* buf, mesh_cb_func_t cb, void* cb_arg,
+	uint16_t qid, uint16_t qflags)
+{
+	struct mesh_cb* r = regional_alloc(s->s.region, 
+		sizeof(struct mesh_cb));
+	if(!r)
+		return 0;
+	r->buf = buf;
+	log_assert(fptr_whitelist_mesh_cb(cb)); /* early failure ifmissing*/
+	r->cb = cb;
+	r->cb_arg = cb_arg;
+	r->edns = *edns;
+	r->qid = qid;
+	r->qflags = qflags;
+	r->next = s->cb_list;
+	s->cb_list = r;
+	return 1;
+
+}
+
+int mesh_state_add_reply(struct mesh_state* s, struct edns_data* edns,
+        struct comm_reply* rep, uint16_t qid, uint16_t qflags, uint8_t* qname)
+{
+	struct mesh_reply* r = regional_alloc(s->s.region, 
+		sizeof(struct mesh_reply));
+	if(!r)
+		return 0;
+	r->query_reply = *rep;
+	r->edns = *edns;
+	r->qid = qid;
+	r->qflags = qflags;
+	r->start_time = *s->s.env->now_tv;
+	r->next = s->reply_list;
+	r->qname = regional_alloc_init(s->s.region, qname, 
+		s->s.qinfo.qname_len);
+	if(!r->qname)
+		return 0;
+	s->reply_list = r;
+	return 1;
+
+}
+
+/**
+ * Continue processing the mesh state at another module.
+ * Handles module to modules tranfer of control.
+ * Handles module finished.
+ * @param mesh: the mesh area.
+ * @param mstate: currently active mesh state.
+ * 	Deleted if finished, calls _done and _supers to 
+ * 	send replies to clients and inform other mesh states.
+ * 	This in turn may create additional runnable mesh states.
+ * @param s: state at which the current module exited.
+ * @param ev: the event sent to the module.
+ * 	returned is the event to send to the next module.
+ * @return true if continue processing at the new module.
+ * 	false if not continued processing is needed.
+ */
+static int
+mesh_continue(struct mesh_area* mesh, struct mesh_state* mstate,
+	enum module_ext_state s, enum module_ev* ev)
+{
+	mstate->num_activated++;
+	if(mstate->num_activated > MESH_MAX_ACTIVATION) {
+		/* module is looping. Stop it. */
+		log_err("internal error: looping module stopped");
+		log_query_info(VERB_QUERY, "pass error for qstate",
+			&mstate->s.qinfo);
+		s = module_error;
+	}
+	if(s == module_wait_module || s == module_restart_next) {
+		/* start next module */
+		mstate->s.curmod++;
+		if(mesh->mods.num == mstate->s.curmod) {
+			log_err("Cannot pass to next module; at last module");
+			log_query_info(VERB_QUERY, "pass error for qstate",
+				&mstate->s.qinfo);
+			mstate->s.curmod--;
+			return mesh_continue(mesh, mstate, module_error, ev);
+		}
+		if(s == module_restart_next) {
+			fptr_ok(fptr_whitelist_mod_clear(
+				mesh->mods.mod[mstate->s.curmod]->clear));
+			(*mesh->mods.mod[mstate->s.curmod]->clear)
+				(&mstate->s, mstate->s.curmod);
+			mstate->s.minfo[mstate->s.curmod] = NULL;
+		}
+		*ev = module_event_pass;
+		return 1;
+	}
+	if(s == module_error && mstate->s.return_rcode == LDNS_RCODE_NOERROR) {
+		/* error is bad, handle pass back up below */
+		mstate->s.return_rcode = LDNS_RCODE_SERVFAIL;
+	}
+	if(s == module_error || s == module_finished) {
+		if(mstate->s.curmod == 0) {
+			mesh_query_done(mstate);
+			mesh_walk_supers(mesh, mstate);
+			mesh_state_delete(&mstate->s);
+			return 0;
+		}
+		/* pass along the locus of control */
+		mstate->s.curmod --;
+		*ev = module_event_moddone;
+		return 1;
+	}
+	return 0;
+}
+
+void mesh_run(struct mesh_area* mesh, struct mesh_state* mstate,
+	enum module_ev ev, struct outbound_entry* e)
+{
+	enum module_ext_state s;
+	verbose(VERB_ALGO, "mesh_run: start");
+	while(mstate) {
+		/* run the module */
+		fptr_ok(fptr_whitelist_mod_operate(
+			mesh->mods.mod[mstate->s.curmod]->operate));
+		(*mesh->mods.mod[mstate->s.curmod]->operate)
+			(&mstate->s, ev, mstate->s.curmod, e);
+
+		/* examine results */
+		mstate->s.reply = NULL;
+		regional_free_all(mstate->s.env->scratch);
+		s = mstate->s.ext_state[mstate->s.curmod];
+		verbose(VERB_ALGO, "mesh_run: %s module exit state is %s", 
+			mesh->mods.mod[mstate->s.curmod]->name, strextstate(s));
+		e = NULL;
+		if(mesh_continue(mesh, mstate, s, &ev))
+			continue;
+
+		/* run more modules */
+		ev = module_event_pass;
+		if(mesh->run.count > 0) {
+			/* pop random element off the runnable tree */
+			mstate = (struct mesh_state*)mesh->run.root->key;
+			(void)rbtree_delete(&mesh->run, mstate);
+		} else mstate = NULL;
+	}
+	if(verbosity >= VERB_ALGO) {
+		mesh_stats(mesh, "mesh_run: end");
+		mesh_log_list(mesh);
+	}
+}
+
+void 
+mesh_log_list(struct mesh_area* mesh)
+{
+	char buf[30];
+	struct mesh_state* m;
+	int num = 0;
+	RBTREE_FOR(m, struct mesh_state*, &mesh->all) {
+		snprintf(buf, sizeof(buf), "%d%s%s%s%s%s mod%d %s%s", 
+			num++, (m->s.is_priming)?"p":"",  /* prime */
+			(m->s.query_flags&BIT_RD)?"RD":"",
+			(m->s.query_flags&BIT_CD)?"CD":"",
+			(m->super_set.count==0)?"d":"", /* detached */
+			(m->sub_set.count!=0)?"c":"",  /* children */
+			m->s.curmod, (m->reply_list)?"rep":"", /*hasreply*/
+			(m->cb_list)?"cb":"" /* callbacks */
+			); 
+		log_query_info(VERB_ALGO, buf, &m->s.qinfo);
+	}
+}
+
+void 
+mesh_stats(struct mesh_area* mesh, const char* str)
+{
+	verbose(VERB_DETAIL, "%s %u recursion states (%u with reply, "
+		"%u detached), %u waiting replies, %u recursion replies "
+		"sent, %d replies dropped, %d states jostled out", 
+		str, (unsigned)mesh->all.count, 
+		(unsigned)mesh->num_reply_states,
+		(unsigned)mesh->num_detached_states,
+		(unsigned)mesh->num_reply_addrs,
+		(unsigned)mesh->replies_sent,
+		(unsigned)mesh->stats_dropped,
+		(unsigned)mesh->stats_jostled);
+	if(mesh->replies_sent > 0) {
+		struct timeval avg;
+		timeval_divide(&avg, &mesh->replies_sum_wait, 
+			mesh->replies_sent);
+		log_info("average recursion processing time "
+			"%d.%6.6d sec", (int)avg.tv_sec, (int)avg.tv_usec);
+		log_info("histogram of recursion processing times");
+		timehist_log(mesh->histogram, "recursions");
+	}
+}
+
+void 
+mesh_stats_clear(struct mesh_area* mesh)
+{
+	if(!mesh)
+		return;
+	mesh->replies_sent = 0;
+	mesh->replies_sum_wait.tv_sec = 0;
+	mesh->replies_sum_wait.tv_usec = 0;
+	mesh->stats_jostled = 0;
+	mesh->stats_dropped = 0;
+	timehist_clear(mesh->histogram);
+	mesh->ans_secure = 0;
+	mesh->ans_bogus = 0;
+	memset(&mesh->ans_rcode[0], 0, sizeof(size_t)*16);
+	mesh->ans_nodata = 0;
+}
+
+size_t 
+mesh_get_mem(struct mesh_area* mesh)
+{
+	struct mesh_state* m;
+	size_t s = sizeof(*mesh) + sizeof(struct timehist) +
+		sizeof(struct th_buck)*mesh->histogram->num +
+		sizeof(ldns_buffer) + ldns_buffer_capacity(mesh->qbuf_bak);
+	RBTREE_FOR(m, struct mesh_state*, &mesh->all) {
+		/* all, including m itself allocated in qstate region */
+		s += regional_get_mem(m->s.region);
+	}
+	return s;
+}
+
+int 
+mesh_detect_cycle(struct module_qstate* qstate, struct query_info* qinfo,
+	uint16_t flags, int prime)
+{
+	struct mesh_area* mesh = qstate->env->mesh;
+	struct mesh_state* dep_m = mesh_area_find(mesh, qinfo, flags, prime);
+	return mesh_detect_cycle_found(qstate, dep_m);
+}
+
+void mesh_list_insert(struct mesh_state* m, struct mesh_state** fp,
+        struct mesh_state** lp)
+{
+	/* insert as last element */
+	m->prev = *lp;
+	m->next = NULL;
+	if(*lp)
+		(*lp)->next = m;
+	else	*fp = m;
+	*lp = m;
+}
+
+void mesh_list_remove(struct mesh_state* m, struct mesh_state** fp,
+        struct mesh_state** lp)
+{
+	if(m->next)
+		m->next->prev = m->prev;
+	else	*lp = m->prev;
+	if(m->prev)
+		m->prev->next = m->next;
+	else	*fp = m->next;
+}