network_cmds-596.100.2.tar.gz

[apple/network_cmds.git] / unbound / services / mesh.c

/*
 * 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 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 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 "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"
#include "ldns/sbuffer.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.is_valrec && !b->s.is_valrec)
                return -1;
        if(!a->s.is_valrec && b->s.is_valrec)
                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 = sldns_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);
        sldns_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, sldns_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) sldns_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) sldns_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)
{
        struct mesh_state* s = mesh_area_find(mesh, qinfo, qflags&(BIT_RD|BIT_CD), 0, 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|BIT_CD), 0, 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 =
#else
                (void)
#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, sldns_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|BIT_CD), 0, 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|BIT_CD), 0, 0);
                if(!s) {
                        return 0;
                }
#ifdef UNBOUND_DEBUG
                n =
#else
                (void)
#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, time_t leeway)
{
        struct mesh_state* s = mesh_area_find(mesh, qinfo, qflags&(BIT_RD|BIT_CD), 0, 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|BIT_CD), 0, 0);
        if(!s) {
                log_err("prefetch mesh_state_create: out of memory");
                return;
        }
#ifdef UNBOUND_DEBUG
        n =
#else
        (void)
#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, int valrec)
{
        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.is_valrec = valrec;
        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 =
#else
                (void)
#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, int valrec, 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,
                valrec);
        int was_detached;
        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,
                        valrec);
                if(!sub) {
                        log_err("mesh_attach_sub: out of memory");
                        return 0;
                }
#ifdef UNBOUND_DEBUG
                n =
#else
                (void)
#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 =
#else
                (void)
#endif
                rbtree_insert(&mesh->run, &sub->run_node);
                log_assert(n != NULL);
                *newq = &sub->s;
        } else
                *newq = NULL;
        was_detached = (sub->super_set.count == 0);
        if(!mesh_state_attachment(qstate->mesh_info, sub))
                return 0;
        /* if it was a duplicate  attachment, the count was not zero before */
        if(!sub->reply_list && !sub->cb_list && was_detached && 
                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;
        if(!rbtree_insert(&sub->super_set, &superref->node)) {
                /* this should not happen, iterator and validator do not
                 * attach subqueries that are identical. */
                /* already attached, we are done, nothing todo.
                 * since superref and subref already allocated in region,
                 * we cannot free them */
                return 1;
        }
#ifdef UNBOUND_DEBUG
        n =
#else
        (void)
#endif
        rbtree_insert(&super->sub_set, &subref->node);
        log_assert(n != NULL); /* we checked above if statement, the reverse
          administration should not fail now, unless they are out of sync */
        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;
                sldns_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)
                        sldns_buffer_copy(r->query_reply.c->buffer, 
                                prev->query_reply.c->buffer);
                sldns_buffer_write_at(r->query_reply.c->buffer, 0, 
                        &r->qid, sizeof(uint16_t));
                sldns_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 " ARG_LL "d.%6.6d sec",
                (long long)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(sldns_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(sldns_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, int valrec)
{
        struct mesh_state key;
        struct mesh_state* result;

        key.node.key = &key;
        key.s.is_priming = prime;
        key.s.is_valrec = valrec;
        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,
        sldns_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%s mod%d %s%s", 
                        num++, (m->s.is_priming)?"p":"",  /* prime */
                        (m->s.is_valrec)?"v":"",  /* 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 "
                        ARG_LL "d.%6.6d sec",
                        (long long)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(sldns_buffer) + sldns_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, int valrec)
{
        struct mesh_area* mesh = qstate->env->mesh;
        struct mesh_state* dep_m = mesh_area_find(mesh, qinfo, flags, prime,
                valrec);
        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;
}