/* * iterator/iterator.c - iterative resolver DNS query response module * * 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 a module that performs recusive iterative DNS query * processing. */ #include "config.h" #include #include "iterator/iterator.h" #include "iterator/iter_utils.h" #include "iterator/iter_hints.h" #include "iterator/iter_fwd.h" #include "iterator/iter_donotq.h" #include "iterator/iter_delegpt.h" #include "iterator/iter_resptype.h" #include "iterator/iter_scrub.h" #include "iterator/iter_priv.h" #include "validator/val_neg.h" #include "services/cache/dns.h" #include "services/cache/infra.h" #include "util/module.h" #include "util/netevent.h" #include "util/net_help.h" #include "util/regional.h" #include "util/data/dname.h" #include "util/data/msgencode.h" #include "util/fptr_wlist.h" #include "util/config_file.h" int iter_init(struct module_env* env, int id) { struct iter_env* iter_env = (struct iter_env*)calloc(1, sizeof(struct iter_env)); if(!iter_env) { log_err("malloc failure"); return 0; } env->modinfo[id] = (void*)iter_env; if(!iter_apply_cfg(iter_env, env->cfg)) { log_err("iterator: could not apply configuration settings."); return 0; } return 1; } void iter_deinit(struct module_env* env, int id) { struct iter_env* iter_env; if(!env || !env->modinfo[id]) return; iter_env = (struct iter_env*)env->modinfo[id]; free(iter_env->target_fetch_policy); priv_delete(iter_env->priv); hints_delete(iter_env->hints); donotq_delete(iter_env->donotq); free(iter_env); env->modinfo[id] = NULL; } /** new query for iterator */ static int iter_new(struct module_qstate* qstate, int id) { struct iter_qstate* iq = (struct iter_qstate*)regional_alloc( qstate->region, sizeof(struct iter_qstate)); qstate->minfo[id] = iq; if(!iq) return 0; memset(iq, 0, sizeof(*iq)); iq->state = INIT_REQUEST_STATE; iq->final_state = FINISHED_STATE; iq->an_prepend_list = NULL; iq->an_prepend_last = NULL; iq->ns_prepend_list = NULL; iq->ns_prepend_last = NULL; iq->dp = NULL; iq->depth = 0; iq->num_target_queries = 0; iq->num_current_queries = 0; iq->query_restart_count = 0; iq->referral_count = 0; iq->sent_count = 0; iq->wait_priming_stub = 0; iq->refetch_glue = 0; iq->dnssec_expected = 0; iq->dnssec_lame_query = 0; iq->chase_flags = qstate->query_flags; /* Start with the (current) qname. */ iq->qchase = qstate->qinfo; outbound_list_init(&iq->outlist); return 1; } /** * Transition to the next state. This can be used to advance a currently * processing event. It cannot be used to reactivate a forEvent. * * @param iq: iterator query state * @param nextstate The state to transition to. * @return true. This is so this can be called as the return value for the * actual process*State() methods. (Transitioning to the next state * implies further processing). */ static int next_state(struct iter_qstate* iq, enum iter_state nextstate) { /* If transitioning to a "response" state, make sure that there is a * response */ if(iter_state_is_responsestate(nextstate)) { if(iq->response == NULL) { log_err("transitioning to response state sans " "response."); } } iq->state = nextstate; return 1; } /** * Transition an event to its final state. Final states always either return * a result up the module chain, or reactivate a dependent event. Which * final state to transtion to is set in the module state for the event when * it was created, and depends on the original purpose of the event. * * The response is stored in the qstate->buf buffer. * * @param iq: iterator query state * @return false. This is so this method can be used as the return value for * the processState methods. (Transitioning to the final state */ static int final_state(struct iter_qstate* iq) { return next_state(iq, iq->final_state); } /** * Callback routine to handle errors in parent query states * @param qstate: query state that failed. * @param id: module id. * @param super: super state. */ static void error_supers(struct module_qstate* qstate, int id, struct module_qstate* super) { struct iter_qstate* super_iq = (struct iter_qstate*)super->minfo[id]; if(qstate->qinfo.qtype == LDNS_RR_TYPE_A || qstate->qinfo.qtype == LDNS_RR_TYPE_AAAA) { /* mark address as failed. */ struct delegpt_ns* dpns = NULL; if(super_iq->dp) dpns = delegpt_find_ns(super_iq->dp, qstate->qinfo.qname, qstate->qinfo.qname_len); if(!dpns) { /* not interested */ verbose(VERB_ALGO, "subq error, but not interested"); log_query_info(VERB_ALGO, "superq", &super->qinfo); if(super_iq->dp) delegpt_log(VERB_ALGO, super_iq->dp); log_assert(0); return; } else { /* see if the failure did get (parent-lame) info */ if(!cache_fill_missing(super->env, super_iq->qchase.qclass, super->region, super_iq->dp)) log_err("out of memory adding missing"); } dpns->resolved = 1; /* mark as failed */ super_iq->num_target_queries--; } if(qstate->qinfo.qtype == LDNS_RR_TYPE_NS) { /* prime failed to get delegation */ super_iq->dp = NULL; } /* evaluate targets again */ super_iq->state = QUERYTARGETS_STATE; /* super becomes runnable, and will process this change */ } /** * Return an error to the client * @param qstate: our query state * @param id: module id * @param rcode: error code (DNS errcode). * @return: 0 for use by caller, to make notation easy, like: * return error_response(..). */ static int error_response(struct module_qstate* qstate, int id, int rcode) { verbose(VERB_QUERY, "return error response %s", ldns_lookup_by_id(ldns_rcodes, rcode)? ldns_lookup_by_id(ldns_rcodes, rcode)->name:"??"); qstate->return_rcode = rcode; qstate->return_msg = NULL; qstate->ext_state[id] = module_finished; return 0; } /** * Return an error to the client and cache the error code in the * message cache (so per qname, qtype, qclass). * @param qstate: our query state * @param id: module id * @param rcode: error code (DNS errcode). * @return: 0 for use by caller, to make notation easy, like: * return error_response(..). */ static int error_response_cache(struct module_qstate* qstate, int id, int rcode) { /* store in cache */ struct reply_info err; memset(&err, 0, sizeof(err)); err.flags = (uint16_t)(BIT_QR | BIT_RA); FLAGS_SET_RCODE(err.flags, rcode); err.qdcount = 1; err.ttl = NORR_TTL; err.prefetch_ttl = PREFETCH_TTL_CALC(err.ttl); /* do not waste time trying to validate this servfail */ err.security = sec_status_indeterminate; verbose(VERB_ALGO, "store error response in message cache"); if(!iter_dns_store(qstate->env, &qstate->qinfo, &err, 0, 0, NULL)) { log_err("error_response_cache: could not store error (nomem)"); } return error_response(qstate, id, rcode); } /** check if prepend item is duplicate item */ static int prepend_is_duplicate(struct ub_packed_rrset_key** sets, size_t to, struct ub_packed_rrset_key* dup) { size_t i; for(i=0; irk.type == dup->rk.type && sets[i]->rk.rrset_class == dup->rk.rrset_class && sets[i]->rk.dname_len == dup->rk.dname_len && query_dname_compare(sets[i]->rk.dname, dup->rk.dname) == 0) return 1; } return 0; } /** prepend the prepend list in the answer and authority section of dns_msg */ static int iter_prepend(struct iter_qstate* iq, struct dns_msg* msg, struct regional* region) { struct iter_prep_list* p; struct ub_packed_rrset_key** sets; size_t num_an = 0, num_ns = 0;; for(p = iq->an_prepend_list; p; p = p->next) num_an++; for(p = iq->ns_prepend_list; p; p = p->next) num_ns++; if(num_an + num_ns == 0) return 1; verbose(VERB_ALGO, "prepending %d rrsets", (int)num_an + (int)num_ns); sets = regional_alloc(region, (num_an+num_ns+msg->rep->rrset_count) * sizeof(struct ub_packed_rrset_key*)); if(!sets) return 0; /* ANSWER section */ num_an = 0; for(p = iq->an_prepend_list; p; p = p->next) { sets[num_an++] = p->rrset; } memcpy(sets+num_an, msg->rep->rrsets, msg->rep->an_numrrsets * sizeof(struct ub_packed_rrset_key*)); /* AUTH section */ num_ns = 0; for(p = iq->ns_prepend_list; p; p = p->next) { if(prepend_is_duplicate(sets+msg->rep->an_numrrsets+num_an, num_ns, p->rrset) || prepend_is_duplicate( msg->rep->rrsets+msg->rep->an_numrrsets, msg->rep->ns_numrrsets, p->rrset)) continue; sets[msg->rep->an_numrrsets + num_an + num_ns++] = p->rrset; } memcpy(sets + num_an + msg->rep->an_numrrsets + num_ns, msg->rep->rrsets + msg->rep->an_numrrsets, (msg->rep->ns_numrrsets + msg->rep->ar_numrrsets) * sizeof(struct ub_packed_rrset_key*)); /* NXDOMAIN rcode can stay if we prepended DNAME/CNAMEs, because * this is what recursors should give. */ msg->rep->rrset_count += num_an + num_ns; msg->rep->an_numrrsets += num_an; msg->rep->ns_numrrsets += num_ns; msg->rep->rrsets = sets; return 1; } /** * Add rrset to ANSWER prepend list * @param qstate: query state. * @param iq: iterator query state. * @param rrset: rrset to add. * @return false on failure (malloc). */ static int iter_add_prepend_answer(struct module_qstate* qstate, struct iter_qstate* iq, struct ub_packed_rrset_key* rrset) { struct iter_prep_list* p = (struct iter_prep_list*)regional_alloc( qstate->region, sizeof(struct iter_prep_list)); if(!p) return 0; p->rrset = rrset; p->next = NULL; /* add at end */ if(iq->an_prepend_last) iq->an_prepend_last->next = p; else iq->an_prepend_list = p; iq->an_prepend_last = p; return 1; } /** * Add rrset to AUTHORITY prepend list * @param qstate: query state. * @param iq: iterator query state. * @param rrset: rrset to add. * @return false on failure (malloc). */ static int iter_add_prepend_auth(struct module_qstate* qstate, struct iter_qstate* iq, struct ub_packed_rrset_key* rrset) { struct iter_prep_list* p = (struct iter_prep_list*)regional_alloc( qstate->region, sizeof(struct iter_prep_list)); if(!p) return 0; p->rrset = rrset; p->next = NULL; /* add at end */ if(iq->ns_prepend_last) iq->ns_prepend_last->next = p; else iq->ns_prepend_list = p; iq->ns_prepend_last = p; return 1; } /** * Given a CNAME response (defined as a response containing a CNAME or DNAME * that does not answer the request), process the response, modifying the * state as necessary. This follows the CNAME/DNAME chain and returns the * final query name. * * sets the new query name, after following the CNAME/DNAME chain. * @param qstate: query state. * @param iq: iterator query state. * @param msg: the response. * @param mname: returned target new query name. * @param mname_len: length of mname. * @return false on (malloc) error. */ static int handle_cname_response(struct module_qstate* qstate, struct iter_qstate* iq, struct dns_msg* msg, uint8_t** mname, size_t* mname_len) { size_t i; /* Start with the (current) qname. */ *mname = iq->qchase.qname; *mname_len = iq->qchase.qname_len; /* Iterate over the ANSWER rrsets in order, looking for CNAMEs and * DNAMES. */ for(i=0; irep->an_numrrsets; i++) { struct ub_packed_rrset_key* r = msg->rep->rrsets[i]; /* If there is a (relevant) DNAME, add it to the list. * We always expect there to be CNAME that was generated * by this DNAME following, so we don't process the DNAME * directly. */ if(ntohs(r->rk.type) == LDNS_RR_TYPE_DNAME && dname_strict_subdomain_c(*mname, r->rk.dname)) { if(!iter_add_prepend_answer(qstate, iq, r)) return 0; continue; } if(ntohs(r->rk.type) == LDNS_RR_TYPE_CNAME && query_dname_compare(*mname, r->rk.dname) == 0) { /* Add this relevant CNAME rrset to the prepend list.*/ if(!iter_add_prepend_answer(qstate, iq, r)) return 0; get_cname_target(r, mname, mname_len); } /* Other rrsets in the section are ignored. */ } /* add authority rrsets to authority prepend, for wildcarded CNAMEs */ for(i=msg->rep->an_numrrsets; irep->an_numrrsets + msg->rep->ns_numrrsets; i++) { struct ub_packed_rrset_key* r = msg->rep->rrsets[i]; /* only add NSEC/NSEC3, as they may be needed for validation */ if(ntohs(r->rk.type) == LDNS_RR_TYPE_NSEC || ntohs(r->rk.type) == LDNS_RR_TYPE_NSEC3) { if(!iter_add_prepend_auth(qstate, iq, r)) return 0; } } return 1; } /** * Generate a subrequest. * Generate a local request event. Local events are tied to this module, and * have a correponding (first tier) event that is waiting for this event to * resolve to continue. * * @param qname The query name for this request. * @param qnamelen length of qname * @param qtype The query type for this request. * @param qclass The query class for this request. * @param qstate The event that is generating this event. * @param id: module id. * @param iq: The iterator state that is generating this event. * @param initial_state The initial response state (normally this * is QUERY_RESP_STATE, unless it is known that the request won't * need iterative processing * @param finalstate The final state for the response to this request. * @param subq_ret: if newly allocated, the subquerystate, or NULL if it does * not need initialisation. * @param v: if true, validation is done on the subquery. * @return false on error (malloc). */ static int generate_sub_request(uint8_t* qname, size_t qnamelen, uint16_t qtype, uint16_t qclass, struct module_qstate* qstate, int id, struct iter_qstate* iq, enum iter_state initial_state, enum iter_state finalstate, struct module_qstate** subq_ret, int v) { struct module_qstate* subq = NULL; struct iter_qstate* subiq = NULL; uint16_t qflags = 0; /* OPCODE QUERY, no flags */ struct query_info qinf; int prime = (finalstate == PRIME_RESP_STATE)?1:0; qinf.qname = qname; qinf.qname_len = qnamelen; qinf.qtype = qtype; qinf.qclass = qclass; /* RD should be set only when sending the query back through the INIT * state. */ if(initial_state == INIT_REQUEST_STATE) qflags |= BIT_RD; /* We set the CD flag so we can send this through the "head" of * the resolution chain, which might have a validator. We are * uninterested in validating things not on the direct resolution * path. */ if(!v) qflags |= BIT_CD; /* attach subquery, lookup existing or make a new one */ fptr_ok(fptr_whitelist_modenv_attach_sub(qstate->env->attach_sub)); if(!(*qstate->env->attach_sub)(qstate, &qinf, qflags, prime, &subq)) { return 0; } *subq_ret = subq; if(subq) { /* initialise the new subquery */ subq->curmod = id; subq->ext_state[id] = module_state_initial; subq->minfo[id] = regional_alloc(subq->region, sizeof(struct iter_qstate)); if(!subq->minfo[id]) { log_err("init subq: out of memory"); fptr_ok(fptr_whitelist_modenv_kill_sub( qstate->env->kill_sub)); (*qstate->env->kill_sub)(subq); return 0; } subiq = (struct iter_qstate*)subq->minfo[id]; memset(subiq, 0, sizeof(*subiq)); subiq->num_target_queries = 0; subiq->num_current_queries = 0; subiq->depth = iq->depth+1; outbound_list_init(&subiq->outlist); subiq->state = initial_state; subiq->final_state = finalstate; subiq->qchase = subq->qinfo; subiq->chase_flags = subq->query_flags; subiq->refetch_glue = 0; } return 1; } /** * Generate and send a root priming request. * @param qstate: the qtstate that triggered the need to prime. * @param iq: iterator query state. * @param ie: iterator global state. * @param id: module id. * @param qclass: the class to prime. * @return 0 on failure */ static int prime_root(struct module_qstate* qstate, struct iter_qstate* iq, struct iter_env* ie, int id, uint16_t qclass) { struct delegpt* dp; struct module_qstate* subq; verbose(VERB_DETAIL, "priming . %s NS", ldns_lookup_by_id(ldns_rr_classes, (int)qclass)? ldns_lookup_by_id(ldns_rr_classes, (int)qclass)->name:"??"); dp = hints_lookup_root(ie->hints, qclass); if(!dp) { verbose(VERB_ALGO, "Cannot prime due to lack of hints"); return 0; } /* Priming requests start at the QUERYTARGETS state, skipping * the normal INIT state logic (which would cause an infloop). */ if(!generate_sub_request((uint8_t*)"\000", 1, LDNS_RR_TYPE_NS, qclass, qstate, id, iq, QUERYTARGETS_STATE, PRIME_RESP_STATE, &subq, 0)) { verbose(VERB_ALGO, "could not prime root"); return 0; } if(subq) { struct iter_qstate* subiq = (struct iter_qstate*)subq->minfo[id]; /* Set the initial delegation point to the hint. * copy dp, it is now part of the root prime query. * dp was part of in the fixed hints structure. */ subiq->dp = delegpt_copy(dp, subq->region); if(!subiq->dp) { log_err("out of memory priming root, copydp"); fptr_ok(fptr_whitelist_modenv_kill_sub( qstate->env->kill_sub)); (*qstate->env->kill_sub)(subq); return 0; } /* there should not be any target queries. */ subiq->num_target_queries = 0; subiq->dnssec_expected = iter_indicates_dnssec( qstate->env, subiq->dp, NULL, subq->qinfo.qclass); } /* this module stops, our submodule starts, and does the query. */ qstate->ext_state[id] = module_wait_subquery; return 1; } /** * Generate and process a stub priming request. This method tests for the * need to prime a stub zone, so it is safe to call for every request. * * @param qstate: the qtstate that triggered the need to prime. * @param iq: iterator query state. * @param ie: iterator global state. * @param id: module id. * @param q: request name. * @return true if a priming subrequest was made, false if not. The will only * issue a priming request if it detects an unprimed stub. * Uses value of 2 to signal during stub-prime in root-prime situation * that a noprime-stub is available and resolution can continue. */ static int prime_stub(struct module_qstate* qstate, struct iter_qstate* iq, struct iter_env* ie, int id, struct query_info* q) { /* Lookup the stub hint. This will return null if the stub doesn't * need to be re-primed. */ struct iter_hints_stub* stub; struct delegpt* stub_dp; struct module_qstate* subq; uint8_t* delname = q->qname; size_t delnamelen = q->qname_len; if(q->qtype == LDNS_RR_TYPE_DS && !dname_is_root(q->qname)) /* remove first label, but not for root */ dname_remove_label(&delname, &delnamelen); stub = hints_lookup_stub(ie->hints, delname, q->qclass, iq->dp); /* The stub (if there is one) does not need priming. */ if(!stub) return 0; stub_dp = stub->dp; /* is it a noprime stub (always use) */ if(stub->noprime) { int r = 0; if(iq->dp == NULL) r = 2; /* copy the dp out of the fixed hints structure, so that * it can be changed when servicing this query */ iq->dp = delegpt_copy(stub_dp, qstate->region); if(!iq->dp) { log_err("out of memory priming stub"); (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL); return 1; /* return 1 to make module stop, with error */ } log_nametypeclass(VERB_DETAIL, "use stub", stub_dp->name, LDNS_RR_TYPE_NS, q->qclass); return r; } /* Otherwise, we need to (re)prime the stub. */ log_nametypeclass(VERB_DETAIL, "priming stub", stub_dp->name, LDNS_RR_TYPE_NS, q->qclass); /* Stub priming events start at the QUERYTARGETS state to avoid the * redundant INIT state processing. */ if(!generate_sub_request(stub_dp->name, stub_dp->namelen, LDNS_RR_TYPE_NS, q->qclass, qstate, id, iq, QUERYTARGETS_STATE, PRIME_RESP_STATE, &subq, 0)) { verbose(VERB_ALGO, "could not prime stub"); (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL); return 1; /* return 1 to make module stop, with error */ } if(subq) { struct iter_qstate* subiq = (struct iter_qstate*)subq->minfo[id]; /* Set the initial delegation point to the hint. */ /* make copy to avoid use of stub dp by different qs/threads */ subiq->dp = delegpt_copy(stub_dp, subq->region); if(!subiq->dp) { log_err("out of memory priming stub, copydp"); fptr_ok(fptr_whitelist_modenv_kill_sub( qstate->env->kill_sub)); (*qstate->env->kill_sub)(subq); (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL); return 1; /* return 1 to make module stop, with error */ } /* there should not be any target queries -- although there * wouldn't be anyway, since stub hints never have * missing targets. */ subiq->num_target_queries = 0; subiq->wait_priming_stub = 1; subiq->dnssec_expected = iter_indicates_dnssec( qstate->env, subiq->dp, NULL, subq->qinfo.qclass); } /* this module stops, our submodule starts, and does the query. */ qstate->ext_state[id] = module_wait_subquery; return 1; } /** * Generate A and AAAA checks for glue that is in-zone for the referral * we just got to obtain authoritative information on the adresses. * * @param qstate: the qtstate that triggered the need to prime. * @param iq: iterator query state. * @param id: module id. */ static void generate_a_aaaa_check(struct module_qstate* qstate, struct iter_qstate* iq, int id) { struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id]; struct module_qstate* subq; size_t i; struct reply_info* rep = iq->response->rep; struct ub_packed_rrset_key* s; log_assert(iq->dp); if(iq->depth == ie->max_dependency_depth) return; /* walk through additional, and check if in-zone, * only relevant A, AAAA are left after scrub anyway */ for(i=rep->an_numrrsets+rep->ns_numrrsets; irrset_count; i++) { s = rep->rrsets[i]; /* check *ALL* addresses that are transmitted in additional*/ /* is it an address ? */ if( !(ntohs(s->rk.type)==LDNS_RR_TYPE_A || ntohs(s->rk.type)==LDNS_RR_TYPE_AAAA)) { continue; } /* is this query the same as the A/AAAA check for it */ if(qstate->qinfo.qtype == ntohs(s->rk.type) && qstate->qinfo.qclass == ntohs(s->rk.rrset_class) && query_dname_compare(qstate->qinfo.qname, s->rk.dname)==0 && (qstate->query_flags&BIT_RD) && !(qstate->query_flags&BIT_CD)) continue; /* generate subrequest for it */ log_nametypeclass(VERB_ALGO, "schedule addr fetch", s->rk.dname, ntohs(s->rk.type), ntohs(s->rk.rrset_class)); if(!generate_sub_request(s->rk.dname, s->rk.dname_len, ntohs(s->rk.type), ntohs(s->rk.rrset_class), qstate, id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1)) { verbose(VERB_ALGO, "could not generate addr check"); return; } /* ignore subq - not need for more init */ } } /** * Generate a NS check request to obtain authoritative information * on an NS rrset. * * @param qstate: the qtstate that triggered the need to prime. * @param iq: iterator query state. * @param id: module id. */ static void generate_ns_check(struct module_qstate* qstate, struct iter_qstate* iq, int id) { struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id]; struct module_qstate* subq; log_assert(iq->dp); if(iq->depth == ie->max_dependency_depth) return; /* is this query the same as the nscheck? */ if(qstate->qinfo.qtype == LDNS_RR_TYPE_NS && query_dname_compare(iq->dp->name, qstate->qinfo.qname)==0 && (qstate->query_flags&BIT_RD) && !(qstate->query_flags&BIT_CD)){ /* spawn off A, AAAA queries for in-zone glue to check */ generate_a_aaaa_check(qstate, iq, id); return; } log_nametypeclass(VERB_ALGO, "schedule ns fetch", iq->dp->name, LDNS_RR_TYPE_NS, iq->qchase.qclass); if(!generate_sub_request(iq->dp->name, iq->dp->namelen, LDNS_RR_TYPE_NS, iq->qchase.qclass, qstate, id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1)) { verbose(VERB_ALGO, "could not generate ns check"); return; } if(subq) { struct iter_qstate* subiq = (struct iter_qstate*)subq->minfo[id]; /* make copy to avoid use of stub dp by different qs/threads */ /* refetch glue to start higher up the tree */ subiq->refetch_glue = 1; subiq->dp = delegpt_copy(iq->dp, subq->region); if(!subiq->dp) { log_err("out of memory generating ns check, copydp"); fptr_ok(fptr_whitelist_modenv_kill_sub( qstate->env->kill_sub)); (*qstate->env->kill_sub)(subq); return; } } } /** * Generate a DNSKEY prefetch query to get the DNSKEY for the DS record we * just got in a referral (where we have dnssec_expected, thus have trust * anchors above it). Note that right after calling this routine the * iterator detached subqueries (because of following the referral), and thus * the DNSKEY query becomes detached, its return stored in the cache for * later lookup by the validator. This cache lookup by the validator avoids * the roundtrip incurred by the DNSKEY query. The DNSKEY query is now * performed at about the same time the original query is sent to the domain, * thus the two answers are likely to be returned at about the same time, * saving a roundtrip from the validated lookup. * * @param qstate: the qtstate that triggered the need to prime. * @param iq: iterator query state. * @param id: module id. */ static void generate_dnskey_prefetch(struct module_qstate* qstate, struct iter_qstate* iq, int id) { struct module_qstate* subq; log_assert(iq->dp); /* is this query the same as the prefetch? */ if(qstate->qinfo.qtype == LDNS_RR_TYPE_DNSKEY && query_dname_compare(iq->dp->name, qstate->qinfo.qname)==0 && (qstate->query_flags&BIT_RD) && !(qstate->query_flags&BIT_CD)){ return; } /* if the DNSKEY is in the cache this lookup will stop quickly */ log_nametypeclass(VERB_ALGO, "schedule dnskey prefetch", iq->dp->name, LDNS_RR_TYPE_DNSKEY, iq->qchase.qclass); if(!generate_sub_request(iq->dp->name, iq->dp->namelen, LDNS_RR_TYPE_DNSKEY, iq->qchase.qclass, qstate, id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0)) { /* we'll be slower, but it'll work */ verbose(VERB_ALGO, "could not generate dnskey prefetch"); return; } if(subq) { struct iter_qstate* subiq = (struct iter_qstate*)subq->minfo[id]; /* this qstate has the right delegation for the dnskey lookup*/ /* make copy to avoid use of stub dp by different qs/threads */ subiq->dp = delegpt_copy(iq->dp, subq->region); /* if !subiq->dp, it'll start from the cache, no problem */ } } /** * See if the query needs forwarding. * * @param qstate: query state. * @param iq: iterator query state. * @return true if the request is forwarded, false if not. * If returns true but, iq->dp is NULL then a malloc failure occurred. */ static int forward_request(struct module_qstate* qstate, struct iter_qstate* iq) { struct delegpt* dp; uint8_t* delname = iq->qchase.qname; size_t delnamelen = iq->qchase.qname_len; /* strip one label off of DS query to lookup higher for it */ if(iq->qchase.qtype == LDNS_RR_TYPE_DS && !dname_is_root(iq->qchase.qname)) dname_remove_label(&delname, &delnamelen); dp = forwards_lookup(qstate->env->fwds, delname, iq->qchase.qclass); if(!dp) return 0; /* send recursion desired to forward addr */ iq->chase_flags |= BIT_RD; iq->dp = delegpt_copy(dp, qstate->region); /* iq->dp checked by caller */ verbose(VERB_ALGO, "forwarding request"); return 1; } /** * Process the initial part of the request handling. This state roughly * corresponds to resolver algorithms steps 1 (find answer in cache) and 2 * (find the best servers to ask). * * Note that all requests start here, and query restarts revisit this state. * * This state either generates: 1) a response, from cache or error, 2) a * priming event, or 3) forwards the request to the next state (init2, * generally). * * @param qstate: query state. * @param iq: iterator query state. * @param ie: iterator shared global environment. * @param id: module id. * @return true if the event needs more request processing immediately, * false if not. */ static int processInitRequest(struct module_qstate* qstate, struct iter_qstate* iq, struct iter_env* ie, int id) { uint8_t* delname; size_t delnamelen; struct dns_msg* msg; log_query_info(VERB_DETAIL, "resolving", &qstate->qinfo); /* check effort */ /* We enforce a maximum number of query restarts. This is primarily a * cheap way to prevent CNAME loops. */ if(iq->query_restart_count > MAX_RESTART_COUNT) { verbose(VERB_QUERY, "request has exceeded the maximum number" " of query restarts with %d", iq->query_restart_count); return error_response(qstate, id, LDNS_RCODE_SERVFAIL); } /* We enforce a maximum recursion/dependency depth -- in general, * this is unnecessary for dependency loops (although it will * catch those), but it provides a sensible limit to the amount * of work required to answer a given query. */ verbose(VERB_ALGO, "request has dependency depth of %d", iq->depth); if(iq->depth > ie->max_dependency_depth) { verbose(VERB_QUERY, "request has exceeded the maximum " "dependency depth with depth of %d", iq->depth); return error_response(qstate, id, LDNS_RCODE_SERVFAIL); } /* If the request is qclass=ANY, setup to generate each class */ if(qstate->qinfo.qclass == LDNS_RR_CLASS_ANY) { iq->qchase.qclass = 0; return next_state(iq, COLLECT_CLASS_STATE); } /* Resolver Algorithm Step 1 -- Look for the answer in local data. */ /* This either results in a query restart (CNAME cache response), a * terminating response (ANSWER), or a cache miss (null). */ if(qstate->blacklist) { /* if cache, or anything else, was blacklisted then * getting older results from cache is a bad idea, no cache */ verbose(VERB_ALGO, "cache blacklisted, going to the network"); msg = NULL; } else { msg = dns_cache_lookup(qstate->env, iq->qchase.qname, iq->qchase.qname_len, iq->qchase.qtype, iq->qchase.qclass, qstate->region, qstate->env->scratch); if(!msg && qstate->env->neg_cache) { /* lookup in negative cache; may result in * NOERROR/NODATA or NXDOMAIN answers that need validation */ msg = val_neg_getmsg(qstate->env->neg_cache, &iq->qchase, qstate->region, qstate->env->rrset_cache, qstate->env->scratch_buffer, *qstate->env->now, 1/*add SOA*/, NULL); } /* item taken from cache does not match our query name, thus * security needs to be re-examined later */ if(msg && query_dname_compare(qstate->qinfo.qname, iq->qchase.qname) != 0) msg->rep->security = sec_status_unchecked; } if(msg) { /* handle positive cache response */ enum response_type type = response_type_from_cache(msg, &iq->qchase); if(verbosity >= VERB_ALGO) { log_dns_msg("msg from cache lookup", &msg->qinfo, msg->rep); verbose(VERB_ALGO, "msg ttl is %d, prefetch ttl %d", (int)msg->rep->ttl, (int)msg->rep->prefetch_ttl); } if(type == RESPONSE_TYPE_CNAME) { uint8_t* sname = 0; size_t slen = 0; verbose(VERB_ALGO, "returning CNAME response from " "cache"); if(!handle_cname_response(qstate, iq, msg, &sname, &slen)) return error_response(qstate, id, LDNS_RCODE_SERVFAIL); iq->qchase.qname = sname; iq->qchase.qname_len = slen; /* This *is* a query restart, even if it is a cheap * one. */ iq->dp = NULL; iq->refetch_glue = 0; iq->query_restart_count++; iq->sent_count = 0; sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region); return next_state(iq, INIT_REQUEST_STATE); } /* if from cache, NULL, else insert 'cache IP' len=0 */ if(qstate->reply_origin) sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region); /* it is an answer, response, to final state */ verbose(VERB_ALGO, "returning answer from cache."); iq->response = msg; return final_state(iq); } /* attempt to forward the request */ if(forward_request(qstate, iq)) { if(!iq->dp) { log_err("alloc failure for forward dp"); return error_response(qstate, id, LDNS_RCODE_SERVFAIL); } iq->refetch_glue = 0; /* the request has been forwarded. * forwarded requests need to be immediately sent to the * next state, QUERYTARGETS. */ return next_state(iq, QUERYTARGETS_STATE); } /* Resolver Algorithm Step 2 -- find the "best" servers. */ /* first, adjust for DS queries. To avoid the grandparent problem, * we just look for the closest set of server to the parent of qname. * When re-fetching glue we also need to ask the parent. */ if(iq->refetch_glue) { if(!iq->dp) { log_err("internal or malloc fail: no dp for refetch"); return error_response(qstate, id, LDNS_RCODE_SERVFAIL); } delname = iq->dp->name; delnamelen = iq->dp->namelen; } else { delname = iq->qchase.qname; delnamelen = iq->qchase.qname_len; } if(iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue || (iq->qchase.qtype == LDNS_RR_TYPE_NS && qstate->prefetch_leeway)) { /* remove first label from delname, root goes to hints, * but only to fetch glue, not for qtype=DS. */ /* also when prefetching an NS record, fetch it again from * its parent, just as if it expired, so that you do not * get stuck on an older nameserver that gives old NSrecords */ if(dname_is_root(delname) && (iq->refetch_glue || (iq->qchase.qtype == LDNS_RR_TYPE_NS && qstate->prefetch_leeway))) delname = NULL; /* go to root priming */ else dname_remove_label(&delname, &delnamelen); iq->refetch_glue = 0; /* if CNAME causes restart, no refetch */ } /* delname is the name to lookup a delegation for. If NULL rootprime */ while(1) { /* Lookup the delegation in the cache. If null, then the * cache needs to be primed for the qclass. */ if(delname) iq->dp = dns_cache_find_delegation(qstate->env, delname, delnamelen, iq->qchase.qtype, iq->qchase.qclass, qstate->region, &iq->deleg_msg, *qstate->env->now); else iq->dp = NULL; /* If the cache has returned nothing, then we have a * root priming situation. */ if(iq->dp == NULL) { /* if there is a stub, then no root prime needed */ int r = prime_stub(qstate, iq, ie, id, &iq->qchase); if(r == 2) break; /* got noprime-stub-zone, continue */ else if(r) return 0; /* stub prime request made */ if(forwards_lookup_root(qstate->env->fwds, iq->qchase.qclass)) { /* forward zone root, no root prime needed */ /* fill in some dp - safety belt */ iq->dp = hints_lookup_root(ie->hints, iq->qchase.qclass); if(!iq->dp) { log_err("internal error: no hints dp"); return error_response(qstate, id, LDNS_RCODE_SERVFAIL); } iq->dp = delegpt_copy(iq->dp, qstate->region); if(!iq->dp) { log_err("out of memory in safety belt"); return error_response(qstate, id, LDNS_RCODE_SERVFAIL); } return next_state(iq, INIT_REQUEST_2_STATE); } /* Note that the result of this will set a new * DelegationPoint based on the result of priming. */ if(!prime_root(qstate, iq, ie, id, iq->qchase.qclass)) return error_response(qstate, id, LDNS_RCODE_REFUSED); /* priming creates and sends a subordinate query, with * this query as the parent. So further processing for * this event will stop until reactivated by the * results of priming. */ return 0; } /* see if this dp not useless. * It is useless if: * o all NS items are required glue. * or the query is for NS item that is required glue. * o no addresses are provided. * o RD qflag is on. * Instead, go up one level, and try to get even further * If the root was useless, use safety belt information. * Only check cache returns, because replies for servers * could be useless but lead to loops (bumping into the * same server reply) if useless-checked. */ if(iter_dp_is_useless(&qstate->qinfo, qstate->query_flags, iq->dp)) { if(dname_is_root(iq->dp->name)) { /* use safety belt */ verbose(VERB_QUERY, "Cache has root NS but " "no addresses. Fallback to the safety belt."); iq->dp = hints_lookup_root(ie->hints, iq->qchase.qclass); /* note deleg_msg is from previous lookup, * but RD is on, so it is not used */ if(!iq->dp) { log_err("internal error: no hints dp"); return error_response(qstate, id, LDNS_RCODE_REFUSED); } iq->dp = delegpt_copy(iq->dp, qstate->region); if(!iq->dp) { log_err("out of memory in safety belt"); return error_response(qstate, id, LDNS_RCODE_SERVFAIL); } break; } else { verbose(VERB_ALGO, "cache delegation was useless:"); delegpt_log(VERB_ALGO, iq->dp); /* go up */ delname = iq->dp->name; delnamelen = iq->dp->namelen; dname_remove_label(&delname, &delnamelen); } } else break; } verbose(VERB_ALGO, "cache delegation returns delegpt"); delegpt_log(VERB_ALGO, iq->dp); /* Otherwise, set the current delegation point and move on to the * next state. */ return next_state(iq, INIT_REQUEST_2_STATE); } /** * Process the second part of the initial request handling. This state * basically exists so that queries that generate root priming events have * the same init processing as ones that do not. Request events that reach * this state must have a valid currentDelegationPoint set. * * This part is primarly handling stub zone priming. Events that reach this * state must have a current delegation point. * * @param qstate: query state. * @param iq: iterator query state. * @param ie: iterator shared global environment. * @param id: module id. * @return true if the event needs more request processing immediately, * false if not. */ static int processInitRequest2(struct module_qstate* qstate, struct iter_qstate* iq, struct iter_env* ie, int id) { log_query_info(VERB_QUERY, "resolving (init part 2): ", &qstate->qinfo); /* Check to see if we need to prime a stub zone. */ if(prime_stub(qstate, iq, ie, id, &iq->qchase)) { /* A priming sub request was made */ return 0; } /* most events just get forwarded to the next state. */ return next_state(iq, INIT_REQUEST_3_STATE); } /** * Process the third part of the initial request handling. This state exists * as a separate state so that queries that generate stub priming events * will get the tail end of the init process but not repeat the stub priming * check. * * @param qstate: query state. * @param iq: iterator query state. * @param id: module id. * @return true, advancing the event to the QUERYTARGETS_STATE. */ static int processInitRequest3(struct module_qstate* qstate, struct iter_qstate* iq, int id) { log_query_info(VERB_QUERY, "resolving (init part 3): ", &qstate->qinfo); /* if the cache reply dp equals a validation anchor or msg has DS, * then DNSSEC RRSIGs are expected in the reply */ iq->dnssec_expected = iter_indicates_dnssec(qstate->env, iq->dp, iq->deleg_msg, iq->qchase.qclass); /* If the RD flag wasn't set, then we just finish with the * cached referral as the response. */ if(!(qstate->query_flags & BIT_RD)) { iq->response = iq->deleg_msg; if(verbosity >= VERB_ALGO) log_dns_msg("no RD requested, using delegation msg", &iq->response->qinfo, iq->response->rep); if(qstate->reply_origin) sock_list_insert(&qstate->reply_origin, NULL, 0, qstate->region); return final_state(iq); } /* After this point, unset the RD flag -- this query is going to * be sent to an auth. server. */ iq->chase_flags &= ~BIT_RD; /* if dnssec expected, fetch key for the trust-anchor or cached-DS */ if(iq->dnssec_expected && qstate->env->cfg->prefetch_key && !(qstate->query_flags&BIT_CD)) { generate_dnskey_prefetch(qstate, iq, id); fptr_ok(fptr_whitelist_modenv_detach_subs( qstate->env->detach_subs)); (*qstate->env->detach_subs)(qstate); } /* Jump to the next state. */ return next_state(iq, QUERYTARGETS_STATE); } /** * Given a basic query, generate a parent-side "target" query. * These are subordinate queries for missing delegation point target addresses, * for which only the parent of the delegation provides correct IP addresses. * * @param qstate: query state. * @param iq: iterator query state. * @param id: module id. * @param name: target qname. * @param namelen: target qname length. * @param qtype: target qtype (either A or AAAA). * @param qclass: target qclass. * @return true on success, false on failure. */ static int generate_parentside_target_query(struct module_qstate* qstate, struct iter_qstate* iq, int id, uint8_t* name, size_t namelen, uint16_t qtype, uint16_t qclass) { struct module_qstate* subq; if(!generate_sub_request(name, namelen, qtype, qclass, qstate, id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0)) return 0; if(subq) { struct iter_qstate* subiq = (struct iter_qstate*)subq->minfo[id]; /* blacklist the cache - we want to fetch parent stuff */ sock_list_insert(&subq->blacklist, NULL, 0, subq->region); subiq->query_for_pside_glue = 1; if(dname_subdomain_c(name, iq->dp->name)) { subiq->dp = delegpt_copy(iq->dp, subq->region); subiq->dnssec_expected = iter_indicates_dnssec( qstate->env, subiq->dp, NULL, subq->qinfo.qclass); subiq->refetch_glue = 1; } else { subiq->dp = dns_cache_find_delegation(qstate->env, name, namelen, qtype, qclass, subq->region, &subiq->deleg_msg, *qstate->env->now); /* if no dp, then it's from root, refetch unneeded */ if(subiq->dp) { subiq->dnssec_expected = iter_indicates_dnssec( qstate->env, subiq->dp, NULL, subq->qinfo.qclass); subiq->refetch_glue = 1; } } } log_nametypeclass(VERB_QUERY, "new pside target", name, qtype, qclass); return 1; } /** * Given a basic query, generate a "target" query. These are subordinate * queries for missing delegation point target addresses. * * @param qstate: query state. * @param iq: iterator query state. * @param id: module id. * @param name: target qname. * @param namelen: target qname length. * @param qtype: target qtype (either A or AAAA). * @param qclass: target qclass. * @return true on success, false on failure. */ static int generate_target_query(struct module_qstate* qstate, struct iter_qstate* iq, int id, uint8_t* name, size_t namelen, uint16_t qtype, uint16_t qclass) { struct module_qstate* subq; if(!generate_sub_request(name, namelen, qtype, qclass, qstate, id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0)) return 0; log_nametypeclass(VERB_QUERY, "new target", name, qtype, qclass); return 1; } /** * Given an event at a certain state, generate zero or more target queries * for it's current delegation point. * * @param qstate: query state. * @param iq: iterator query state. * @param ie: iterator shared global environment. * @param id: module id. * @param maxtargets: The maximum number of targets to query for. * if it is negative, there is no maximum number of targets. * @param num: returns the number of queries generated and processed, * which may be zero if there were no missing targets. * @return false on error. */ static int query_for_targets(struct module_qstate* qstate, struct iter_qstate* iq, struct iter_env* ie, int id, int maxtargets, int* num) { int query_count = 0; struct delegpt_ns* ns; int missing; int toget = 0; if(iq->depth == ie->max_dependency_depth) return 0; iter_mark_cycle_targets(qstate, iq->dp); missing = (int)delegpt_count_missing_targets(iq->dp); log_assert(maxtargets != 0); /* that would not be useful */ /* Generate target requests. Basically, any missing targets * are queried for here, regardless if it is necessary to do * so to continue processing. */ if(maxtargets < 0 || maxtargets > missing) toget = missing; else toget = maxtargets; if(toget == 0) { *num = 0; return 1; } /* select 'toget' items from the total of 'missing' items */ log_assert(toget <= missing); /* loop over missing targets */ for(ns = iq->dp->nslist; ns; ns = ns->next) { if(ns->resolved) continue; /* randomly select this item with probability toget/missing */ if(!iter_ns_probability(qstate->env->rnd, toget, missing)) { /* do not select this one, next; select toget number * of items from a list one less in size */ missing --; continue; } if(ie->supports_ipv6 && !ns->got6) { /* Send the AAAA request. */ if(!generate_target_query(qstate, iq, id, ns->name, ns->namelen, LDNS_RR_TYPE_AAAA, iq->qchase.qclass)) { *num = query_count; if(query_count > 0) qstate->ext_state[id] = module_wait_subquery; return 0; } query_count++; } /* Send the A request. */ if(ie->supports_ipv4 && !ns->got4) { if(!generate_target_query(qstate, iq, id, ns->name, ns->namelen, LDNS_RR_TYPE_A, iq->qchase.qclass)) { *num = query_count; if(query_count > 0) qstate->ext_state[id] = module_wait_subquery; return 0; } query_count++; } /* mark this target as in progress. */ ns->resolved = 1; missing--; toget--; if(toget == 0) break; } *num = query_count; if(query_count > 0) qstate->ext_state[id] = module_wait_subquery; return 1; } /** * Called by processQueryTargets when it would like extra targets to query * but it seems to be out of options. At last resort some less appealing * options are explored. If there are no more options, the result is SERVFAIL * * @param qstate: query state. * @param iq: iterator query state. * @param ie: iterator shared global environment. * @param id: module id. * @return true if the event requires more request processing immediately, * false if not. */ static int processLastResort(struct module_qstate* qstate, struct iter_qstate* iq, struct iter_env* ie, int id) { struct delegpt_ns* ns; int query_count = 0; verbose(VERB_ALGO, "No more query targets, attempting last resort"); log_assert(iq->dp); if(!iq->dp->has_parent_side_NS) { if(!iter_lookup_parent_NS_from_cache(qstate->env, iq->dp, qstate->region, &qstate->qinfo) || !iq->dp->has_parent_side_NS) { /* if: malloc failure in lookup go up to try */ /* if: no parent NS in cache - go up one level */ verbose(VERB_ALGO, "try to grab parent NS"); iq->store_parent_NS = iq->dp; iq->deleg_msg = NULL; iq->refetch_glue = 1; iq->query_restart_count++; iq->sent_count = 0; return next_state(iq, INIT_REQUEST_STATE); } } /* see if that makes new names available */ if(!cache_fill_missing(qstate->env, iq->qchase.qclass, qstate->region, iq->dp)) log_err("out of memory in cache_fill_missing"); if(iq->dp->usable_list) { verbose(VERB_ALGO, "try parent-side-name, w. glue from cache"); return next_state(iq, QUERYTARGETS_STATE); } /* try to fill out parent glue from cache */ if(iter_lookup_parent_glue_from_cache(qstate->env, iq->dp, qstate->region, &qstate->qinfo)) { /* got parent stuff from cache, see if we can continue */ verbose(VERB_ALGO, "try parent-side glue from cache"); return next_state(iq, QUERYTARGETS_STATE); } /* query for an extra name added by the parent-NS record */ if(delegpt_count_missing_targets(iq->dp) > 0) { int qs = 0; verbose(VERB_ALGO, "try parent-side target name"); if(!query_for_targets(qstate, iq, ie, id, 1, &qs)) { return error_response(qstate, id, LDNS_RCODE_SERVFAIL); } iq->num_target_queries += qs; if(qs != 0) { qstate->ext_state[id] = module_wait_subquery; return 0; /* and wait for them */ } } if(iq->depth == ie->max_dependency_depth) { verbose(VERB_QUERY, "maxdepth and need more nameservers, fail"); return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL); } /* mark cycle targets for parent-side lookups */ iter_mark_pside_cycle_targets(qstate, iq->dp); /* see if we can issue queries to get nameserver addresses */ /* this lookup is not randomized, but sequential. */ for(ns = iq->dp->nslist; ns; ns = ns->next) { /* query for parent-side A and AAAA for nameservers */ if(ie->supports_ipv6 && !ns->done_pside6) { /* Send the AAAA request. */ if(!generate_parentside_target_query(qstate, iq, id, ns->name, ns->namelen, LDNS_RR_TYPE_AAAA, iq->qchase.qclass)) return error_response(qstate, id, LDNS_RCODE_SERVFAIL); ns->done_pside6 = 1; query_count++; } if(ie->supports_ipv4 && !ns->done_pside4) { /* Send the A request. */ if(!generate_parentside_target_query(qstate, iq, id, ns->name, ns->namelen, LDNS_RR_TYPE_A, iq->qchase.qclass)) return error_response(qstate, id, LDNS_RCODE_SERVFAIL); ns->done_pside4 = 1; query_count++; } if(query_count != 0) { /* suspend to await results */ verbose(VERB_ALGO, "try parent-side glue lookup"); iq->num_target_queries += query_count; qstate->ext_state[id] = module_wait_subquery; return 0; } } /* if this was a parent-side glue query itself, then store that * failure in cache. */ if(iq->query_for_pside_glue && !iq->pside_glue) iter_store_parentside_neg(qstate->env, &qstate->qinfo, iq->deleg_msg?iq->deleg_msg->rep: (iq->response?iq->response->rep:NULL)); verbose(VERB_QUERY, "out of query targets -- returning SERVFAIL"); /* fail -- no more targets, no more hope of targets, no hope * of a response. */ return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL); } /** * This is the request event state where the request will be sent to one of * its current query targets. This state also handles issuing target lookup * queries for missing target IP addresses. Queries typically iterate on * this state, both when they are just trying different targets for a given * delegation point, and when they change delegation points. This state * roughly corresponds to RFC 1034 algorithm steps 3 and 4. * * @param qstate: query state. * @param iq: iterator query state. * @param ie: iterator shared global environment. * @param id: module id. * @return true if the event requires more request processing immediately, * false if not. This state only returns true when it is generating * a SERVFAIL response because the query has hit a dead end. */ static int processQueryTargets(struct module_qstate* qstate, struct iter_qstate* iq, struct iter_env* ie, int id) { int tf_policy; struct delegpt_addr* target; struct outbound_entry* outq; /* NOTE: a request will encounter this state for each target it * needs to send a query to. That is, at least one per referral, * more if some targets timeout or return throwaway answers. */ log_query_info(VERB_QUERY, "processQueryTargets:", &qstate->qinfo); verbose(VERB_ALGO, "processQueryTargets: targetqueries %d, " "currentqueries %d sentcount %d", iq->num_target_queries, iq->num_current_queries, iq->sent_count); /* Make sure that we haven't run away */ /* FIXME: is this check even necessary? */ if(iq->referral_count > MAX_REFERRAL_COUNT) { verbose(VERB_QUERY, "request has exceeded the maximum " "number of referrrals with %d", iq->referral_count); return error_response(qstate, id, LDNS_RCODE_SERVFAIL); } if(iq->sent_count > MAX_SENT_COUNT) { verbose(VERB_QUERY, "request has exceeded the maximum " "number of sends with %d", iq->sent_count); return error_response(qstate, id, LDNS_RCODE_SERVFAIL); } /* Make sure we have a delegation point, otherwise priming failed * or another failure occurred */ if(!iq->dp) { verbose(VERB_QUERY, "Failed to get a delegation, giving up"); return error_response(qstate, id, LDNS_RCODE_SERVFAIL); } if(!ie->supports_ipv6) delegpt_no_ipv6(iq->dp); if(!ie->supports_ipv4) delegpt_no_ipv4(iq->dp); delegpt_log(VERB_ALGO, iq->dp); if(iq->num_current_queries>0) { /* already busy answering a query, this restart is because * more delegpt addrs became available, wait for existing * query. */ verbose(VERB_ALGO, "woke up, but wait for outstanding query"); qstate->ext_state[id] = module_wait_reply; return 0; } tf_policy = 0; /* < not <=, because although the array is large enough for <=, the * generated query will immediately be discarded due to depth and * that servfail is cached, which is not good as opportunism goes. */ if(iq->depth < ie->max_dependency_depth && iq->sent_count < TARGET_FETCH_STOP) { tf_policy = ie->target_fetch_policy[iq->depth]; } /* if in 0x20 fallback get as many targets as possible */ if(iq->caps_fallback) { int extra = 0; size_t naddr, nres, navail; if(!query_for_targets(qstate, iq, ie, id, -1, &extra)) { return error_response(qstate, id, LDNS_RCODE_SERVFAIL); } iq->num_target_queries += extra; if(iq->num_target_queries > 0) { /* wait to get all targets, we want to try em */ verbose(VERB_ALGO, "wait for all targets for fallback"); qstate->ext_state[id] = module_wait_reply; return 0; } /* did we do enough fallback queries already? */ delegpt_count_addr(iq->dp, &naddr, &nres, &navail); /* the current caps_server is the number of fallbacks sent. * the original query is one that matched too, so we have * caps_server+1 number of matching queries now */ if(iq->caps_server+1 >= naddr*3 || iq->caps_server+1 >= MAX_SENT_COUNT) { /* we're done, process the response */ verbose(VERB_ALGO, "0x20 fallback had %d responses " "match for %d wanted, done.", (int)iq->caps_server+1, (int)naddr*3); iq->caps_fallback = 0; iter_dec_attempts(iq->dp, 3); /* space for fallback */ iq->num_current_queries++; /* RespState decrements it*/ iq->referral_count++; /* make sure we don't loop */ iq->sent_count = 0; iq->state = QUERY_RESP_STATE; return 1; } verbose(VERB_ALGO, "0x20 fallback number %d", (int)iq->caps_server); /* if there is a policy to fetch missing targets * opportunistically, do it. we rely on the fact that once a * query (or queries) for a missing name have been issued, * they will not show up again. */ } else if(tf_policy != 0) { int extra = 0; verbose(VERB_ALGO, "attempt to get extra %d targets", tf_policy); (void)query_for_targets(qstate, iq, ie, id, tf_policy, &extra); /* errors ignored, these targets are not strictly necessary for * this result, we do not have to reply with SERVFAIL */ iq->num_target_queries += extra; } /* Add the current set of unused targets to our queue. */ delegpt_add_unused_targets(iq->dp); /* Select the next usable target, filtering out unsuitable targets. */ target = iter_server_selection(ie, qstate->env, iq->dp, iq->dp->name, iq->dp->namelen, iq->qchase.qtype, &iq->dnssec_lame_query, &iq->chase_to_rd, iq->num_target_queries, qstate->blacklist); /* If no usable target was selected... */ if(!target) { /* Here we distinguish between three states: generate a new * target query, just wait, or quit (with a SERVFAIL). * We have the following information: number of active * target queries, number of active current queries, * the presence of missing targets at this delegation * point, and the given query target policy. */ /* Check for the wait condition. If this is true, then * an action must be taken. */ if(iq->num_target_queries==0 && iq->num_current_queries==0) { /* If there is nothing to wait for, then we need * to distinguish between generating (a) new target * query, or failing. */ if(delegpt_count_missing_targets(iq->dp) > 0) { int qs = 0; verbose(VERB_ALGO, "querying for next " "missing target"); if(!query_for_targets(qstate, iq, ie, id, 1, &qs)) { return error_response(qstate, id, LDNS_RCODE_SERVFAIL); } if(qs == 0 && delegpt_count_missing_targets(iq->dp) == 0){ /* it looked like there were missing * targets, but they did not turn up. * Try the bad choices again (if any), * when we get back here missing==0, * so this is not a loop. */ return 1; } iq->num_target_queries += qs; } /* Since a target query might have been made, we * need to check again. */ if(iq->num_target_queries == 0) { return processLastResort(qstate, iq, ie, id); } } /* otherwise, we have no current targets, so submerge * until one of the target or direct queries return. */ if(iq->num_target_queries>0 && iq->num_current_queries>0) { verbose(VERB_ALGO, "no current targets -- waiting " "for %d targets to resolve or %d outstanding" " queries to respond", iq->num_target_queries, iq->num_current_queries); qstate->ext_state[id] = module_wait_reply; } else if(iq->num_target_queries>0) { verbose(VERB_ALGO, "no current targets -- waiting " "for %d targets to resolve.", iq->num_target_queries); qstate->ext_state[id] = module_wait_subquery; } else { verbose(VERB_ALGO, "no current targets -- waiting " "for %d outstanding queries to respond.", iq->num_current_queries); qstate->ext_state[id] = module_wait_reply; } return 0; } /* We have a valid target. */ if(verbosity >= VERB_QUERY) { log_query_info(VERB_QUERY, "sending query:", &iq->qchase); log_name_addr(VERB_QUERY, "sending to target:", iq->dp->name, &target->addr, target->addrlen); verbose(VERB_ALGO, "dnssec status: %s%s", iq->dnssec_expected?"expected": "not expected", iq->dnssec_lame_query?" but lame_query anyway": ""); } fptr_ok(fptr_whitelist_modenv_send_query(qstate->env->send_query)); outq = (*qstate->env->send_query)( iq->qchase.qname, iq->qchase.qname_len, iq->qchase.qtype, iq->qchase.qclass, iq->chase_flags | (iq->chase_to_rd?BIT_RD:0), EDNS_DO|BIT_CD, iq->dnssec_expected, &target->addr, target->addrlen, iq->dp->name, iq->dp->namelen, qstate); if(!outq) { log_addr(VERB_DETAIL, "error sending query to auth server", &target->addr, target->addrlen); return next_state(iq, QUERYTARGETS_STATE); } outbound_list_insert(&iq->outlist, outq); iq->num_current_queries++; iq->sent_count++; qstate->ext_state[id] = module_wait_reply; return 0; } /** find NS rrset in given list */ static struct ub_packed_rrset_key* find_NS(struct reply_info* rep, size_t from, size_t to) { size_t i; for(i=from; irrsets[i]->rk.type) == LDNS_RR_TYPE_NS) return rep->rrsets[i]; } return NULL; } /** * Process the query response. All queries end up at this state first. This * process generally consists of analyzing the response and routing the * event to the next state (either bouncing it back to a request state, or * terminating the processing for this event). * * @param qstate: query state. * @param iq: iterator query state. * @param id: module id. * @return true if the event requires more immediate processing, false if * not. This is generally only true when forwarding the request to * the final state (i.e., on answer). */ static int processQueryResponse(struct module_qstate* qstate, struct iter_qstate* iq, int id) { int dnsseclame = 0; enum response_type type; iq->num_current_queries--; if(iq->response == NULL) { iq->chase_to_rd = 0; iq->dnssec_lame_query = 0; verbose(VERB_ALGO, "query response was timeout"); return next_state(iq, QUERYTARGETS_STATE); } type = response_type_from_server( (int)((iq->chase_flags&BIT_RD) || iq->chase_to_rd), iq->response, &iq->qchase, iq->dp); iq->chase_to_rd = 0; if(type == RESPONSE_TYPE_REFERRAL && (iq->chase_flags&BIT_RD)) { /* When forwarding (RD bit is set), we handle referrals * differently. No queries should be sent elsewhere */ type = RESPONSE_TYPE_ANSWER; } if(iq->dnssec_expected && !iq->dnssec_lame_query && !(iq->chase_flags&BIT_RD) && type != RESPONSE_TYPE_LAME && type != RESPONSE_TYPE_REC_LAME && type != RESPONSE_TYPE_THROWAWAY && type != RESPONSE_TYPE_UNTYPED) { /* a possible answer, see if it is missing DNSSEC */ /* but not when forwarding, so we dont mark fwder lame */ /* also make sure the answer is from the zone we expected, * otherwise, (due to parent,child on same server), we * might mark the server,zone lame inappropriately */ if(!iter_msg_has_dnssec(iq->response) && iter_msg_from_zone(iq->response, iq->dp, type, iq->qchase.qclass)) { type = RESPONSE_TYPE_LAME; dnsseclame = 1; } } else iq->dnssec_lame_query = 0; /* see if referral brings us close to the target */ if(type == RESPONSE_TYPE_REFERRAL) { struct ub_packed_rrset_key* ns = find_NS( iq->response->rep, iq->response->rep->an_numrrsets, iq->response->rep->an_numrrsets + iq->response->rep->ns_numrrsets); if(!ns) ns = find_NS(iq->response->rep, 0, iq->response->rep->an_numrrsets); if(!ns || !dname_strict_subdomain_c(ns->rk.dname, iq->dp->name) || !dname_subdomain_c(iq->qchase.qname, ns->rk.dname)){ verbose(VERB_ALGO, "bad referral, throwaway"); type = RESPONSE_TYPE_THROWAWAY; } else iter_scrub_ds(iq->response, ns, iq->dp->name); } else iter_scrub_ds(iq->response, NULL, NULL); /* handle each of the type cases */ if(type == RESPONSE_TYPE_ANSWER) { /* ANSWER type responses terminate the query algorithm, * so they sent on their */ if(verbosity >= VERB_DETAIL) { verbose(VERB_DETAIL, "query response was %s", FLAGS_GET_RCODE(iq->response->rep->flags) ==LDNS_RCODE_NXDOMAIN?"NXDOMAIN ANSWER": (iq->response->rep->an_numrrsets?"ANSWER": "nodata ANSWER")); } if(!iter_dns_store(qstate->env, &iq->response->qinfo, iq->response->rep, 0, qstate->prefetch_leeway, qstate->region)) return error_response(qstate, id, LDNS_RCODE_SERVFAIL); /* close down outstanding requests to be discarded */ outbound_list_clear(&iq->outlist); iq->num_current_queries = 0; fptr_ok(fptr_whitelist_modenv_detach_subs( qstate->env->detach_subs)); (*qstate->env->detach_subs)(qstate); iq->num_target_queries = 0; if(qstate->reply) sock_list_insert(&qstate->reply_origin, &qstate->reply->addr, qstate->reply->addrlen, qstate->region); return final_state(iq); } else if(type == RESPONSE_TYPE_REFERRAL) { /* REFERRAL type responses get a reset of the * delegation point, and back to the QUERYTARGETS_STATE. */ verbose(VERB_DETAIL, "query response was REFERRAL"); /* if hardened, only store referral if we asked for it */ if(!qstate->env->cfg->harden_referral_path || ( qstate->qinfo.qtype == LDNS_RR_TYPE_NS && (qstate->query_flags&BIT_RD) && !(qstate->query_flags&BIT_CD) /* we know that all other NS rrsets are scrubbed * away, thus on referral only one is left. * see if that equals the query name... */ && ( /* auth section, but sometimes in answer section*/ reply_find_rrset_section_ns(iq->response->rep, iq->qchase.qname, iq->qchase.qname_len, LDNS_RR_TYPE_NS, iq->qchase.qclass) || reply_find_rrset_section_an(iq->response->rep, iq->qchase.qname, iq->qchase.qname_len, LDNS_RR_TYPE_NS, iq->qchase.qclass) ) )) { /* Store the referral under the current query */ /* no prefetch-leeway, since its not the answer */ if(!iter_dns_store(qstate->env, &iq->response->qinfo, iq->response->rep, 1, 0, NULL)) return error_response(qstate, id, LDNS_RCODE_SERVFAIL); if(iq->store_parent_NS) iter_store_parentside_NS(qstate->env, iq->response->rep); if(qstate->env->neg_cache) val_neg_addreferral(qstate->env->neg_cache, iq->response->rep, iq->dp->name); } /* store parent-side-in-zone-glue, if directly queried for */ if(iq->query_for_pside_glue && !iq->pside_glue) { iq->pside_glue = reply_find_rrset(iq->response->rep, iq->qchase.qname, iq->qchase.qname_len, iq->qchase.qtype, iq->qchase.qclass); if(iq->pside_glue) { log_rrset_key(VERB_ALGO, "found parent-side " "glue", iq->pside_glue); iter_store_parentside_rrset(qstate->env, iq->pside_glue); } } /* Reset the event state, setting the current delegation * point to the referral. */ iq->deleg_msg = iq->response; iq->dp = delegpt_from_message(iq->response, qstate->region); if(!iq->dp) return error_response(qstate, id, LDNS_RCODE_SERVFAIL); if(!cache_fill_missing(qstate->env, iq->qchase.qclass, qstate->region, iq->dp)) return error_response(qstate, id, LDNS_RCODE_SERVFAIL); if(iq->store_parent_NS && query_dname_compare(iq->dp->name, iq->store_parent_NS->name) == 0) iter_merge_retry_counts(iq->dp, iq->store_parent_NS); delegpt_log(VERB_ALGO, iq->dp); /* Count this as a referral. */ iq->referral_count++; iq->sent_count = 0; /* see if the next dp is a trust anchor, or a DS was sent * along, indicating dnssec is expected for next zone */ iq->dnssec_expected = iter_indicates_dnssec(qstate->env, iq->dp, iq->response, iq->qchase.qclass); /* if dnssec, validating then also fetch the key for the DS */ if(iq->dnssec_expected && qstate->env->cfg->prefetch_key && !(qstate->query_flags&BIT_CD)) generate_dnskey_prefetch(qstate, iq, id); /* spawn off NS and addr to auth servers for the NS we just * got in the referral. This gets authoritative answer * (answer section trust level) rrset. * right after, we detach the subs, answer goes to cache. */ if(qstate->env->cfg->harden_referral_path) generate_ns_check(qstate, iq, id); /* stop current outstanding queries. * FIXME: should the outstanding queries be waited for and * handled? Say by a subquery that inherits the outbound_entry. */ outbound_list_clear(&iq->outlist); iq->num_current_queries = 0; fptr_ok(fptr_whitelist_modenv_detach_subs( qstate->env->detach_subs)); (*qstate->env->detach_subs)(qstate); iq->num_target_queries = 0; verbose(VERB_ALGO, "cleared outbound list for next round"); return next_state(iq, QUERYTARGETS_STATE); } else if(type == RESPONSE_TYPE_CNAME) { uint8_t* sname = NULL; size_t snamelen = 0; /* CNAME type responses get a query restart (i.e., get a * reset of the query state and go back to INIT_REQUEST_STATE). */ verbose(VERB_DETAIL, "query response was CNAME"); if(verbosity >= VERB_ALGO) log_dns_msg("cname msg", &iq->response->qinfo, iq->response->rep); /* Process the CNAME response. */ if(!handle_cname_response(qstate, iq, iq->response, &sname, &snamelen)) return error_response(qstate, id, LDNS_RCODE_SERVFAIL); /* cache the CNAME response under the current query */ /* NOTE : set referral=1, so that rrsets get stored but not * the partial query answer (CNAME only). */ /* prefetchleeway applied because this updates answer parts */ if(!iter_dns_store(qstate->env, &iq->response->qinfo, iq->response->rep, 1, qstate->prefetch_leeway, NULL)) return error_response(qstate, id, LDNS_RCODE_SERVFAIL); /* set the current request's qname to the new value. */ iq->qchase.qname = sname; iq->qchase.qname_len = snamelen; /* Clear the query state, since this is a query restart. */ iq->deleg_msg = NULL; iq->dp = NULL; /* Note the query restart. */ iq->query_restart_count++; iq->sent_count = 0; /* stop current outstanding queries. * FIXME: should the outstanding queries be waited for and * handled? Say by a subquery that inherits the outbound_entry. */ outbound_list_clear(&iq->outlist); iq->num_current_queries = 0; fptr_ok(fptr_whitelist_modenv_detach_subs( qstate->env->detach_subs)); (*qstate->env->detach_subs)(qstate); iq->num_target_queries = 0; if(qstate->reply) sock_list_insert(&qstate->reply_origin, &qstate->reply->addr, qstate->reply->addrlen, qstate->region); verbose(VERB_ALGO, "cleared outbound list for query restart"); /* go to INIT_REQUEST_STATE for new qname. */ return next_state(iq, INIT_REQUEST_STATE); } else if(type == RESPONSE_TYPE_LAME) { /* Cache the LAMEness. */ verbose(VERB_DETAIL, "query response was %sLAME", dnsseclame?"DNSSEC ":""); if(!dname_subdomain_c(iq->qchase.qname, iq->dp->name)) { log_err("mark lame: mismatch in qname and dpname"); /* throwaway this reply below */ } else if(qstate->reply) { /* need addr for lameness cache, but we may have * gotten this from cache, so test to be sure */ if(!infra_set_lame(qstate->env->infra_cache, &qstate->reply->addr, qstate->reply->addrlen, iq->dp->name, iq->dp->namelen, *qstate->env->now, dnsseclame, 0, iq->qchase.qtype)) log_err("mark host lame: out of memory"); } else log_err("%slame response from cache", dnsseclame?"DNSSEC ":""); } else if(type == RESPONSE_TYPE_REC_LAME) { /* Cache the LAMEness. */ verbose(VERB_DETAIL, "query response REC_LAME: " "recursive but not authoritative server"); if(!dname_subdomain_c(iq->qchase.qname, iq->dp->name)) { log_err("mark rec_lame: mismatch in qname and dpname"); /* throwaway this reply below */ } else if(qstate->reply) { /* need addr for lameness cache, but we may have * gotten this from cache, so test to be sure */ verbose(VERB_DETAIL, "mark as REC_LAME"); if(!infra_set_lame(qstate->env->infra_cache, &qstate->reply->addr, qstate->reply->addrlen, iq->dp->name, iq->dp->namelen, *qstate->env->now, 0, 1, iq->qchase.qtype)) log_err("mark host lame: out of memory"); } } else if(type == RESPONSE_TYPE_THROWAWAY) { /* LAME and THROWAWAY responses are handled the same way. * In this case, the event is just sent directly back to * the QUERYTARGETS_STATE without resetting anything, * because, clearly, the next target must be tried. */ verbose(VERB_DETAIL, "query response was THROWAWAY"); } else { log_warn("A query response came back with an unknown type: %d", (int)type); } /* LAME, THROWAWAY and "unknown" all end up here. * Recycle to the QUERYTARGETS state to hopefully try a * different target. */ return next_state(iq, QUERYTARGETS_STATE); } /** * Return priming query results to interestes super querystates. * * Sets the delegation point and delegation message (not nonRD queries). * This is a callback from walk_supers. * * @param qstate: priming query state that finished. * @param id: module id. * @param forq: the qstate for which priming has been done. */ static void prime_supers(struct module_qstate* qstate, int id, struct module_qstate* forq) { struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id]; struct delegpt* dp = NULL; log_assert(qstate->is_priming || foriq->wait_priming_stub); log_assert(qstate->return_rcode == LDNS_RCODE_NOERROR); /* Convert our response to a delegation point */ dp = delegpt_from_message(qstate->return_msg, forq->region); if(!dp) { /* if there is no convertable delegation point, then * the ANSWER type was (presumably) a negative answer. */ verbose(VERB_ALGO, "prime response was not a positive " "ANSWER; failing"); foriq->dp = NULL; foriq->state = QUERYTARGETS_STATE; return; } log_query_info(VERB_DETAIL, "priming successful for", &qstate->qinfo); delegpt_log(VERB_ALGO, dp); foriq->dp = dp; foriq->deleg_msg = dns_copy_msg(qstate->return_msg, forq->region); if(!foriq->deleg_msg) { log_err("copy prime response: out of memory"); foriq->dp = NULL; foriq->state = QUERYTARGETS_STATE; return; } /* root priming responses go to init stage 2, priming stub * responses to to stage 3. */ if(foriq->wait_priming_stub) { foriq->state = INIT_REQUEST_3_STATE; foriq->wait_priming_stub = 0; } else foriq->state = INIT_REQUEST_2_STATE; /* because we are finished, the parent will be reactivated */ } /** * This handles the response to a priming query. This is used to handle both * root and stub priming responses. This is basically the equivalent of the * QUERY_RESP_STATE, but will not handle CNAME responses and will treat * REFERRALs as ANSWERS. It will also update and reactivate the originating * event. * * @param qstate: query state. * @param id: module id. * @return true if the event needs more immediate processing, false if not. * This state always returns false. */ static int processPrimeResponse(struct module_qstate* qstate, int id) { struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id]; enum response_type type; iq->response->rep->flags &= ~(BIT_RD|BIT_RA); /* ignore rec-lame */ type = response_type_from_server( (int)((iq->chase_flags&BIT_RD) || iq->chase_to_rd), iq->response, &iq->qchase, iq->dp); if(type == RESPONSE_TYPE_ANSWER) { qstate->return_rcode = LDNS_RCODE_NOERROR; qstate->return_msg = iq->response; } else { qstate->return_rcode = LDNS_RCODE_SERVFAIL; qstate->return_msg = NULL; } /* validate the root or stub after priming (if enabled). * This is the same query as the prime query, but with validation. * Now that we are primed, the additional queries that validation * may need can be resolved, such as DLV. */ if(qstate->env->cfg->harden_referral_path) { struct module_qstate* subq = NULL; log_nametypeclass(VERB_ALGO, "schedule prime validation", qstate->qinfo.qname, qstate->qinfo.qtype, qstate->qinfo.qclass); if(!generate_sub_request(qstate->qinfo.qname, qstate->qinfo.qname_len, qstate->qinfo.qtype, qstate->qinfo.qclass, qstate, id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, 1)) { verbose(VERB_ALGO, "could not generate prime check"); } generate_a_aaaa_check(qstate, iq, id); } /* This event is finished. */ qstate->ext_state[id] = module_finished; return 0; } /** * Do final processing on responses to target queries. Events reach this * state after the iterative resolution algorithm terminates. This state is * responsible for reactiving the original event, and housekeeping related * to received target responses (caching, updating the current delegation * point, etc). * Callback from walk_supers for every super state that is interested in * the results from this query. * * @param qstate: query state. * @param id: module id. * @param forq: super query state. */ static void processTargetResponse(struct module_qstate* qstate, int id, struct module_qstate* forq) { struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id]; struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id]; struct ub_packed_rrset_key* rrset; struct delegpt_ns* dpns; log_assert(qstate->return_rcode == LDNS_RCODE_NOERROR); foriq->state = QUERYTARGETS_STATE; log_query_info(VERB_ALGO, "processTargetResponse", &qstate->qinfo); log_query_info(VERB_ALGO, "processTargetResponse super", &forq->qinfo); /* check to see if parent event is still interested (in orig name). */ if(!foriq->dp) { verbose(VERB_ALGO, "subq: parent not interested, was reset"); return; /* not interested anymore */ } dpns = delegpt_find_ns(foriq->dp, qstate->qinfo.qname, qstate->qinfo.qname_len); if(!dpns) { /* If not interested, just stop processing this event */ verbose(VERB_ALGO, "subq: parent not interested anymore"); /* could be because parent was jostled out of the cache, and a new identical query arrived, that does not want it*/ return; } /* Tell the originating event that this target query has finished * (regardless if it succeeded or not). */ foriq->num_target_queries--; /* if iq->query_for_pside_glue then add the pside_glue (marked lame) */ if(iq->pside_glue) { /* if the pside_glue is NULL, then it could not be found, * the done_pside is already set when created and a cache * entry created in processFinished so nothing to do here */ log_rrset_key(VERB_ALGO, "add parentside glue to dp", iq->pside_glue); if(!delegpt_add_rrset(foriq->dp, forq->region, iq->pside_glue, 1)) log_err("out of memory adding pside glue"); } /* This response is relevant to the current query, so we * add (attempt to add, anyway) this target(s) and reactivate * the original event. * NOTE: we could only look for the AnswerRRset if the * response type was ANSWER. */ rrset = reply_find_answer_rrset(&iq->qchase, qstate->return_msg->rep); if(rrset) { /* if CNAMEs have been followed - add new NS to delegpt. */ /* BTW. RFC 1918 says NS should not have got CNAMEs. Robust. */ if(!delegpt_find_ns(foriq->dp, rrset->rk.dname, rrset->rk.dname_len)) { /* if dpns->lame then set newcname ns lame too */ if(!delegpt_add_ns(foriq->dp, forq->region, rrset->rk.dname, (int)dpns->lame)) log_err("out of memory adding cnamed-ns"); } /* if dpns->lame then set the address(es) lame too */ if(!delegpt_add_rrset(foriq->dp, forq->region, rrset, (int)dpns->lame)) log_err("out of memory adding targets"); verbose(VERB_ALGO, "added target response"); delegpt_log(VERB_ALGO, foriq->dp); } else { verbose(VERB_ALGO, "iterator TargetResponse failed"); dpns->resolved = 1; /* fail the target */ } } /** * Process response for qclass=ANY queries for a particular class. * Append to result or error-exit. * * @param qstate: query state. * @param id: module id. * @param forq: super query state. */ static void processClassResponse(struct module_qstate* qstate, int id, struct module_qstate* forq) { struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id]; struct dns_msg* from = qstate->return_msg; log_query_info(VERB_ALGO, "processClassResponse", &qstate->qinfo); log_query_info(VERB_ALGO, "processClassResponse super", &forq->qinfo); if(qstate->return_rcode != LDNS_RCODE_NOERROR) { /* cause servfail for qclass ANY query */ foriq->response = NULL; foriq->state = FINISHED_STATE; return; } /* append result */ if(!foriq->response) { /* allocate the response: copy RCODE, sec_state */ foriq->response = dns_copy_msg(from, forq->region); if(!foriq->response) { log_err("malloc failed for qclass ANY response"); foriq->state = FINISHED_STATE; return; } foriq->response->qinfo.qclass = forq->qinfo.qclass; /* qclass ANY does not receive the AA flag on replies */ foriq->response->rep->authoritative = 0; } else { struct dns_msg* to = foriq->response; /* add _from_ this response _to_ existing collection */ /* if there are records, copy RCODE */ /* lower sec_state if this message is lower */ if(from->rep->rrset_count != 0) { size_t n = from->rep->rrset_count+to->rep->rrset_count; struct ub_packed_rrset_key** dest, **d; /* copy appropriate rcode */ to->rep->flags = from->rep->flags; /* copy rrsets */ dest = regional_alloc(forq->region, sizeof(dest[0])*n); if(!dest) { log_err("malloc failed in collect ANY"); foriq->state = FINISHED_STATE; return; } d = dest; /* copy AN */ memcpy(dest, to->rep->rrsets, to->rep->an_numrrsets * sizeof(dest[0])); dest += to->rep->an_numrrsets; memcpy(dest, from->rep->rrsets, from->rep->an_numrrsets * sizeof(dest[0])); dest += from->rep->an_numrrsets; /* copy NS */ memcpy(dest, to->rep->rrsets+to->rep->an_numrrsets, to->rep->ns_numrrsets * sizeof(dest[0])); dest += to->rep->ns_numrrsets; memcpy(dest, from->rep->rrsets+from->rep->an_numrrsets, from->rep->ns_numrrsets * sizeof(dest[0])); dest += from->rep->ns_numrrsets; /* copy AR */ memcpy(dest, to->rep->rrsets+to->rep->an_numrrsets+ to->rep->ns_numrrsets, to->rep->ar_numrrsets * sizeof(dest[0])); dest += to->rep->ar_numrrsets; memcpy(dest, from->rep->rrsets+from->rep->an_numrrsets+ from->rep->ns_numrrsets, from->rep->ar_numrrsets * sizeof(dest[0])); /* update counts */ to->rep->rrsets = d; to->rep->an_numrrsets += from->rep->an_numrrsets; to->rep->ns_numrrsets += from->rep->ns_numrrsets; to->rep->ar_numrrsets += from->rep->ar_numrrsets; to->rep->rrset_count = n; } if(from->rep->security < to->rep->security) /* lowest sec */ to->rep->security = from->rep->security; if(from->rep->qdcount != 0) /* insert qd if appropriate */ to->rep->qdcount = from->rep->qdcount; if(from->rep->ttl < to->rep->ttl) /* use smallest TTL */ to->rep->ttl = from->rep->ttl; if(from->rep->prefetch_ttl < to->rep->prefetch_ttl) to->rep->prefetch_ttl = from->rep->prefetch_ttl; } /* are we done? */ foriq->num_current_queries --; if(foriq->num_current_queries == 0) foriq->state = FINISHED_STATE; } /** * Collect class ANY responses and make them into one response. This * state is started and it creates queries for all classes (that have * root hints). The answers are then collected. * * @param qstate: query state. * @param id: module id. * @return true if the event needs more immediate processing, false if not. */ static int processCollectClass(struct module_qstate* qstate, int id) { struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id]; struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id]; struct module_qstate* subq; /* If qchase.qclass == 0 then send out queries for all classes. * Otherwise, do nothing (wait for all answers to arrive and the * processClassResponse to put them together, and that moves us * towards the Finished state when done. */ if(iq->qchase.qclass == 0) { uint16_t c = 0; iq->qchase.qclass = LDNS_RR_CLASS_ANY; while(iter_get_next_root(ie->hints, qstate->env->fwds, &c)) { /* generate query for this class */ log_nametypeclass(VERB_ALGO, "spawn collect query", qstate->qinfo.qname, qstate->qinfo.qtype, c); if(!generate_sub_request(qstate->qinfo.qname, qstate->qinfo.qname_len, qstate->qinfo.qtype, c, qstate, id, iq, INIT_REQUEST_STATE, FINISHED_STATE, &subq, (int)!(qstate->query_flags&BIT_CD))) { return error_response(qstate, id, LDNS_RCODE_SERVFAIL); } /* ignore subq, no special init required */ iq->num_current_queries ++; if(c == 0xffff) break; else c++; } /* if no roots are configured at all, return */ if(iq->num_current_queries == 0) { verbose(VERB_ALGO, "No root hints or fwds, giving up " "on qclass ANY"); return error_response(qstate, id, LDNS_RCODE_REFUSED); } /* return false, wait for queries to return */ } /* if woke up here because of an answer, wait for more answers */ return 0; } /** * This handles the final state for first-tier responses (i.e., responses to * externally generated queries). * * @param qstate: query state. * @param iq: iterator query state. * @param id: module id. * @return true if the event needs more processing, false if not. Since this * is the final state for an event, it always returns false. */ static int processFinished(struct module_qstate* qstate, struct iter_qstate* iq, int id) { log_query_info(VERB_QUERY, "finishing processing for", &qstate->qinfo); /* store negative cache element for parent side glue. */ if(iq->query_for_pside_glue && !iq->pside_glue) iter_store_parentside_neg(qstate->env, &qstate->qinfo, iq->deleg_msg?iq->deleg_msg->rep: (iq->response?iq->response->rep:NULL)); if(!iq->response) { verbose(VERB_ALGO, "No response is set, servfail"); return error_response(qstate, id, LDNS_RCODE_SERVFAIL); } /* Make sure that the RA flag is set (since the presence of * this module means that recursion is available) */ iq->response->rep->flags |= BIT_RA; /* Clear the AA flag */ /* FIXME: does this action go here or in some other module? */ iq->response->rep->flags &= ~BIT_AA; /* make sure QR flag is on */ iq->response->rep->flags |= BIT_QR; /* we have finished processing this query */ qstate->ext_state[id] = module_finished; /* TODO: we are using a private TTL, trim the response. */ /* if (mPrivateTTL > 0){IterUtils.setPrivateTTL(resp, mPrivateTTL); } */ /* prepend any items we have accumulated */ if(iq->an_prepend_list || iq->ns_prepend_list) { if(!iter_prepend(iq, iq->response, qstate->region)) { log_err("prepend rrsets: out of memory"); return error_response(qstate, id, LDNS_RCODE_SERVFAIL); } /* reset the query name back */ iq->response->qinfo = qstate->qinfo; /* the security state depends on the combination */ iq->response->rep->security = sec_status_unchecked; /* store message with the finished prepended items, * but only if we did recursion. The nonrecursion referral * from cache does not need to be stored in the msg cache. */ if(qstate->query_flags&BIT_RD) { if(!iter_dns_store(qstate->env, &qstate->qinfo, iq->response->rep, 0, qstate->prefetch_leeway, qstate->region)) return error_response(qstate, id, LDNS_RCODE_SERVFAIL); } } qstate->return_rcode = LDNS_RCODE_NOERROR; qstate->return_msg = iq->response; return 0; } /* * Return priming query results to interestes super querystates. * * Sets the delegation point and delegation message (not nonRD queries). * This is a callback from walk_supers. * * @param qstate: query state that finished. * @param id: module id. * @param super: the qstate to inform. */ void iter_inform_super(struct module_qstate* qstate, int id, struct module_qstate* super) { if(!qstate->is_priming && super->qinfo.qclass == LDNS_RR_CLASS_ANY) processClassResponse(qstate, id, super); else if(qstate->return_rcode != LDNS_RCODE_NOERROR) error_supers(qstate, id, super); else if(qstate->is_priming) prime_supers(qstate, id, super); else processTargetResponse(qstate, id, super); } /** * Handle iterator state. * Handle events. This is the real processing loop for events, responsible * for moving events through the various states. If a processing method * returns true, then it will be advanced to the next state. If false, then * processing will stop. * * @param qstate: query state. * @param ie: iterator shared global environment. * @param iq: iterator query state. * @param id: module id. */ static void iter_handle(struct module_qstate* qstate, struct iter_qstate* iq, struct iter_env* ie, int id) { int cont = 1; while(cont) { verbose(VERB_ALGO, "iter_handle processing q with state %s", iter_state_to_string(iq->state)); switch(iq->state) { case INIT_REQUEST_STATE: cont = processInitRequest(qstate, iq, ie, id); break; case INIT_REQUEST_2_STATE: cont = processInitRequest2(qstate, iq, ie, id); break; case INIT_REQUEST_3_STATE: cont = processInitRequest3(qstate, iq, id); break; case QUERYTARGETS_STATE: cont = processQueryTargets(qstate, iq, ie, id); break; case QUERY_RESP_STATE: cont = processQueryResponse(qstate, iq, id); break; case PRIME_RESP_STATE: cont = processPrimeResponse(qstate, id); break; case COLLECT_CLASS_STATE: cont = processCollectClass(qstate, id); break; case FINISHED_STATE: cont = processFinished(qstate, iq, id); break; default: log_warn("iterator: invalid state: %d", iq->state); cont = 0; break; } } } /** * This is the primary entry point for processing request events. Note that * this method should only be used by external modules. * @param qstate: query state. * @param ie: iterator shared global environment. * @param iq: iterator query state. * @param id: module id. */ static void process_request(struct module_qstate* qstate, struct iter_qstate* iq, struct iter_env* ie, int id) { /* external requests start in the INIT state, and finish using the * FINISHED state. */ iq->state = INIT_REQUEST_STATE; iq->final_state = FINISHED_STATE; verbose(VERB_ALGO, "process_request: new external request event"); iter_handle(qstate, iq, ie, id); } /** process authoritative server reply */ static void process_response(struct module_qstate* qstate, struct iter_qstate* iq, struct iter_env* ie, int id, struct outbound_entry* outbound, enum module_ev event) { struct msg_parse* prs; struct edns_data edns; ldns_buffer* pkt; verbose(VERB_ALGO, "process_response: new external response event"); iq->response = NULL; iq->state = QUERY_RESP_STATE; if(event == module_event_noreply || event == module_event_error) { goto handle_it; } if( (event != module_event_reply && event != module_event_capsfail) || !qstate->reply) { log_err("Bad event combined with response"); outbound_list_remove(&iq->outlist, outbound); (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL); return; } /* parse message */ prs = (struct msg_parse*)regional_alloc(qstate->env->scratch, sizeof(struct msg_parse)); if(!prs) { log_err("out of memory on incoming message"); /* like packet got dropped */ goto handle_it; } memset(prs, 0, sizeof(*prs)); memset(&edns, 0, sizeof(edns)); pkt = qstate->reply->c->buffer; ldns_buffer_set_position(pkt, 0); if(parse_packet(pkt, prs, qstate->env->scratch) != LDNS_RCODE_NOERROR) { verbose(VERB_ALGO, "parse error on reply packet"); goto handle_it; } /* edns is not examined, but removed from message to help cache */ if(parse_extract_edns(prs, &edns) != LDNS_RCODE_NOERROR) goto handle_it; /* remove CD-bit, we asked for in case we handle validation ourself */ prs->flags &= ~BIT_CD; /* normalize and sanitize: easy to delete items from linked lists */ if(!scrub_message(pkt, prs, &iq->qchase, iq->dp->name, qstate->env->scratch, qstate->env, ie)) goto handle_it; /* allocate response dns_msg in region */ iq->response = dns_alloc_msg(pkt, prs, qstate->region); if(!iq->response) goto handle_it; log_query_info(VERB_DETAIL, "response for", &qstate->qinfo); log_name_addr(VERB_DETAIL, "reply from", iq->dp->name, &qstate->reply->addr, qstate->reply->addrlen); if(verbosity >= VERB_ALGO) log_dns_msg("incoming scrubbed packet:", &iq->response->qinfo, iq->response->rep); if(event == module_event_capsfail) { if(!iq->caps_fallback) { /* start fallback */ iq->caps_fallback = 1; iq->caps_server = 0; iq->caps_reply = iq->response->rep; iq->state = QUERYTARGETS_STATE; iq->num_current_queries--; verbose(VERB_DETAIL, "Capsforid: starting fallback"); goto handle_it; } else { /* check if reply is the same, otherwise, fail */ if(!reply_equal(iq->response->rep, iq->caps_reply, qstate->env->scratch_buffer)) { verbose(VERB_DETAIL, "Capsforid fallback: " "getting different replies, failed"); outbound_list_remove(&iq->outlist, outbound); (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL); return; } /* continue the fallback procedure at next server */ iq->caps_server++; iq->state = QUERYTARGETS_STATE; iq->num_current_queries--; verbose(VERB_DETAIL, "Capsforid: reply is equal. " "go to next fallback"); goto handle_it; } } iq->caps_fallback = 0; /* if we were in fallback, 0x20 is OK now */ handle_it: outbound_list_remove(&iq->outlist, outbound); iter_handle(qstate, iq, ie, id); } void iter_operate(struct module_qstate* qstate, enum module_ev event, int id, struct outbound_entry* outbound) { struct iter_env* ie = (struct iter_env*)qstate->env->modinfo[id]; struct iter_qstate* iq = (struct iter_qstate*)qstate->minfo[id]; verbose(VERB_QUERY, "iterator[module %d] operate: extstate:%s event:%s", id, strextstate(qstate->ext_state[id]), strmodulevent(event)); if(iq) log_query_info(VERB_QUERY, "iterator operate: query", &qstate->qinfo); if(iq && qstate->qinfo.qname != iq->qchase.qname) log_query_info(VERB_QUERY, "iterator operate: chased to", &iq->qchase); /* perform iterator state machine */ if((event == module_event_new || event == module_event_pass) && iq == NULL) { if(!iter_new(qstate, id)) { (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL); return; } iq = (struct iter_qstate*)qstate->minfo[id]; process_request(qstate, iq, ie, id); return; } if(iq && event == module_event_pass) { iter_handle(qstate, iq, ie, id); return; } if(iq && outbound) { process_response(qstate, iq, ie, id, outbound, event); return; } if(event == module_event_error) { verbose(VERB_ALGO, "got called with event error, giving up"); (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL); return; } log_err("bad event for iterator"); (void)error_response(qstate, id, LDNS_RCODE_SERVFAIL); } void iter_clear(struct module_qstate* qstate, int id) { struct iter_qstate* iq; if(!qstate) return; iq = (struct iter_qstate*)qstate->minfo[id]; if(iq) { outbound_list_clear(&iq->outlist); iq->num_current_queries = 0; } qstate->minfo[id] = NULL; } size_t iter_get_mem(struct module_env* env, int id) { struct iter_env* ie = (struct iter_env*)env->modinfo[id]; if(!ie) return 0; return sizeof(*ie) + sizeof(int)*((size_t)ie->max_dependency_depth+1) + hints_get_mem(ie->hints) + donotq_get_mem(ie->donotq) + priv_get_mem(ie->priv); } /** * The iterator function block */ static struct module_func_block iter_block = { "iterator", &iter_init, &iter_deinit, &iter_operate, &iter_inform_super, &iter_clear, &iter_get_mem }; struct module_func_block* iter_get_funcblock(void) { return &iter_block; } const char* iter_state_to_string(enum iter_state state) { switch (state) { case INIT_REQUEST_STATE : return "INIT REQUEST STATE"; case INIT_REQUEST_2_STATE : return "INIT REQUEST STATE (stage 2)"; case INIT_REQUEST_3_STATE: return "INIT REQUEST STATE (stage 3)"; case QUERYTARGETS_STATE : return "QUERY TARGETS STATE"; case PRIME_RESP_STATE : return "PRIME RESPONSE STATE"; case COLLECT_CLASS_STATE : return "COLLECT CLASS STATE"; case QUERY_RESP_STATE : return "QUERY RESPONSE STATE"; case FINISHED_STATE : return "FINISHED RESPONSE STATE"; default : return "UNKNOWN ITER STATE"; } } int iter_state_is_responsestate(enum iter_state s) { switch(s) { case INIT_REQUEST_STATE : case INIT_REQUEST_2_STATE : case INIT_REQUEST_3_STATE : case QUERYTARGETS_STATE : case COLLECT_CLASS_STATE : return 0; default: break; } return 1; }