/*
* 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 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 a module that performs recursive iterative DNS query
* processing.
*/
#include "config.h"
#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 "services/authzone.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"
#include "util/random.h"
#include "sldns/rrdef.h"
#include "sldns/wire2str.h"
#include "sldns/str2wire.h"
#include "sldns/parseutil.h"
#include "sldns/sbuffer.h"
/* in msec */
int UNKNOWN_SERVER_NICENESS = 376;
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;
lock_basic_init(&iter_env->queries_ratelimit_lock);
lock_protect(&iter_env->queries_ratelimit_lock,
&iter_env->num_queries_ratelimited,
sizeof(iter_env->num_queries_ratelimited));
if(!iter_apply_cfg(iter_env, env->cfg)) {
log_err("iterator: could not apply configuration settings.");
return 0;
}
return 1;
}
/** delete caps_whitelist element */
static void
caps_free(struct rbnode_type* n, void* ATTR_UNUSED(d))
{
if(n) {
free(((struct name_tree_node*)n)->name);
free(n);
}
}
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];
lock_basic_destroy(&iter_env->queries_ratelimit_lock);
free(iter_env->target_fetch_policy);
priv_delete(iter_env->priv);
donotq_delete(iter_env->donotq);
if(iter_env->caps_white) {
traverse_postorder(iter_env->caps_white, caps_free, NULL);
free(iter_env->caps_white);
}
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->ratelimit_ok = 0;
iq->target_count = NULL;
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);
iq->minimise_count = 0;
iq->minimise_timeout_count = 0;
if (qstate->env->cfg->qname_minimisation)
iq->minimisation_state = INIT_MINIMISE_STATE;
else
iq->minimisation_state = DONOT_MINIMISE_STATE;
memset(&iq->qinfo_out, 0, sizeof(struct query_info));
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 transition 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;
super_iq->num_target_queries--;
if(super_iq->dp)
dpns = delegpt_find_ns(super_iq->dp,
qstate->qinfo.qname, qstate->qinfo.qname_len);
if(!dpns) {
/* not interested */
/* this can happen, for eg. qname minimisation asked
* for an NXDOMAIN to be validated, and used qtype
* A for that, and the error of that, the name, is
* not listed in super_iq->dp */
verbose(VERB_ALGO, "subq error, but not interested");
log_query_info(VERB_ALGO, "superq", &super->qinfo);
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 */
}
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",
sldns_lookup_by_id(sldns_rcodes, rcode)?
sldns_lookup_by_id(sldns_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)
{
if(!qstate->no_cache_store) {
/* store in cache */
struct reply_info err;
if(qstate->prefetch_leeway > NORR_TTL) {
verbose(VERB_ALGO, "error response for prefetch in cache");
/* attempt to adjust the cache entry prefetch */
if(dns_cache_prefetch_adjust(qstate->env, &qstate->qinfo,
NORR_TTL, qstate->query_flags))
return error_response(qstate, id, rcode);
/* if that fails (not in cache), fall through to store err */
}
if(qstate->env->cfg->serve_expired) {
/* if serving expired contents, and such content is
* already available, don't overwrite this servfail */
struct msgreply_entry* msg;
if((msg=msg_cache_lookup(qstate->env,
qstate->qinfo.qname, qstate->qinfo.qname_len,
qstate->qinfo.qtype, qstate->qinfo.qclass,
qstate->query_flags, 0,
qstate->env->cfg->serve_expired_ttl_reset))
!= NULL) {
if(qstate->env->cfg->serve_expired_ttl_reset) {
struct reply_info* rep =
(struct reply_info*)msg->entry.data;
if(rep && *qstate->env->now +
qstate->env->cfg->serve_expired_ttl >
rep->serve_expired_ttl) {
rep->serve_expired_ttl =
*qstate->env->now +
qstate->env->cfg->serve_expired_ttl;
}
}
lock_rw_unlock(&msg->entry.lock);
return error_response(qstate, id, rcode);
}
/* serving expired contents, but nothing is cached
* at all, so the servfail cache entry is useful
* (stops waste of time on this servfail NORR_TTL) */
} else {
/* don't overwrite existing (non-expired) data in
* cache with a servfail */
struct msgreply_entry* msg;
if((msg=msg_cache_lookup(qstate->env,
qstate->qinfo.qname, qstate->qinfo.qname_len,
qstate->qinfo.qtype, qstate->qinfo.qclass,
qstate->query_flags, *qstate->env->now, 0))
!= NULL) {
struct reply_info* rep = (struct reply_info*)
msg->entry.data;
if(FLAGS_GET_RCODE(rep->flags) ==
LDNS_RCODE_NOERROR ||
FLAGS_GET_RCODE(rep->flags) ==
LDNS_RCODE_NXDOMAIN) {
/* we have a good entry,
* don't overwrite */
lock_rw_unlock(&msg->entry.lock);
return error_response(qstate, id, rcode);
}
lock_rw_unlock(&msg->entry.lock);
}
}
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);
err.serve_expired_ttl = NORR_TTL;
/* do not waste time trying to validate this servfail */
err.security = sec_status_indeterminate;
verbose(VERB_ALGO, "store error response in message cache");
iter_dns_store(qstate->env, &qstate->qinfo, &err, 0, 0, 0, NULL,
qstate->query_flags);
}
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; i<to; i++) {
if(sets[i]->rk.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);
if(num_an > RR_COUNT_MAX || num_ns > RR_COUNT_MAX ||
msg->rep->rrset_count > RR_COUNT_MAX) return 0; /* overflow */
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;
if(ub_packed_rrset_ttl(p->rrset) < msg->rep->ttl)
msg->rep->ttl = ub_packed_rrset_ttl(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;
if(ub_packed_rrset_ttl(p->rrset) < msg->rep->ttl)
msg->rep->ttl = ub_packed_rrset_ttl(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;
}
/**
* Find rrset in ANSWER prepend list.
* to avoid duplicate DNAMEs when a DNAME is traversed twice.
* @param iq: iterator query state.
* @param rrset: rrset to add.
* @return false if not found
*/
static int
iter_find_rrset_in_prepend_answer(struct iter_qstate* iq,
struct ub_packed_rrset_key* rrset)
{
struct iter_prep_list* p = iq->an_prepend_list;
while(p) {
if(ub_rrset_compare(p->rrset, rrset) == 0 &&
rrsetdata_equal((struct packed_rrset_data*)p->rrset
->entry.data, (struct packed_rrset_data*)rrset
->entry.data))
return 1;
p = p->next;
}
return 0;
}
/**
* 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; i<msg->rep->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) &&
!iter_find_rrset_in_prepend_answer(iq, r)) {
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 &&
!iter_find_rrset_in_prepend_answer(iq, r)) {
/* 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; i<msg->rep->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;
}
/** see if last resort is possible - does config allow queries to parent */
static int
can_have_last_resort(struct module_env* env, uint8_t* nm, size_t nmlen,
uint16_t qclass, struct delegpt** retdp)
{
struct delegpt* fwddp;
struct iter_hints_stub* stub;
int labs = dname_count_labels(nm);
/* do not process a last resort (the parent side) if a stub
* or forward is configured, because we do not want to go 'above'
* the configured servers */
if(!dname_is_root(nm) && (stub = (struct iter_hints_stub*)
name_tree_find(&env->hints->tree, nm, nmlen, labs, qclass)) &&
/* has_parent side is turned off for stub_first, where we
* are allowed to go to the parent */
stub->dp->has_parent_side_NS) {
if(retdp) *retdp = stub->dp;
return 0;
}
if((fwddp = forwards_find(env->fwds, nm, qclass)) &&
/* has_parent_side is turned off for forward_first, where
* we are allowed to go to the parent */
fwddp->has_parent_side_NS) {
if(retdp) *retdp = fwddp;
return 0;
}
return 1;
}
/** see if target name is caps-for-id whitelisted */
static int
is_caps_whitelisted(struct iter_env* ie, struct iter_qstate* iq)
{
if(!ie->caps_white) return 0; /* no whitelist, or no capsforid */
return name_tree_lookup(ie->caps_white, iq->qchase.qname,
iq->qchase.qname_len, dname_count_labels(iq->qchase.qname),
iq->qchase.qclass) != NULL;
}
/** create target count structure for this query */
static void
target_count_create(struct iter_qstate* iq)
{
if(!iq->target_count) {
iq->target_count = (int*)calloc(2, sizeof(int));
/* if calloc fails we simply do not track this number */
if(iq->target_count)
iq->target_count[0] = 1;
}
}
static void
target_count_increase(struct iter_qstate* iq, int num)
{
target_count_create(iq);
if(iq->target_count)
iq->target_count[1] += num;
}
/**
* Generate a subrequest.
* Generate a local request event. Local events are tied to this module, and
* have a corresponding (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;
int valrec = 0;
qinf.qname = qname;
qinf.qname_len = qnamelen;
qinf.qtype = qtype;
qinf.qclass = qclass;
qinf.local_alias = NULL;
/* 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;
valrec = 1;
}
/* 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, valrec,
&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;
target_count_create(iq);
subiq->target_count = iq->target_count;
if(iq->target_count)
iq->target_count[0] ++; /* extra reference */
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;
if(qstate->env->cfg->qname_minimisation)
subiq->minimisation_state = INIT_MINIMISE_STATE;
else
subiq->minimisation_state = DONOT_MINIMISE_STATE;
memset(&subiq->qinfo_out, 0, sizeof(struct query_info));
}
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 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, int id,
uint16_t qclass)
{
struct delegpt* dp;
struct module_qstate* subq;
verbose(VERB_DETAIL, "priming . %s NS",
sldns_lookup_by_id(sldns_rr_classes, (int)qclass)?
sldns_lookup_by_id(sldns_rr_classes, (int)qclass)->name:"??");
dp = hints_lookup_root(qstate->env->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 id: module id.
* @param qname: request name.
* @param qclass: request class.
* @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, int id,
uint8_t* qname, uint16_t qclass)
{
/* 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;
if(!qname) return 0;
stub = hints_lookup_stub(qstate->env->hints, qname, qclass, iq->dp);
/* The stub (if there is one) does not need priming. */
if(!stub)
return 0;
stub_dp = stub->dp;
/* if we have an auth_zone dp, and stub is equal, don't prime stub
* yet, unless we want to fallback and avoid the auth_zone */
if(!iq->auth_zone_avoid && iq->dp && iq->dp->auth_dp &&
query_dname_compare(iq->dp->name, stub_dp->name) == 0)
return 0;
/* 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");
errinf(qstate, "malloc failure, 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, qclass);
return r;
}
/* Otherwise, we need to (re)prime the stub. */
log_nametypeclass(VERB_DETAIL, "priming stub", stub_dp->name,
LDNS_RR_TYPE_NS, 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, qclass, qstate, id, iq,
QUERYTARGETS_STATE, PRIME_RESP_STATE, &subq, 0)) {
verbose(VERB_ALGO, "could not prime stub");
errinf(qstate, "could not generate lookup for stub prime");
(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);
errinf(qstate, "malloc failure, in stub prime");
(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 delegation point for an auth zone (unless cached dp is better)
* false on alloc failure.
*/
static int
auth_zone_delegpt(struct module_qstate* qstate, struct iter_qstate* iq,
uint8_t* delname, size_t delnamelen)
{
struct auth_zone* z;
if(iq->auth_zone_avoid)
return 1;
if(!delname) {
delname = iq->qchase.qname;
delnamelen = iq->qchase.qname_len;
}
lock_rw_rdlock(&qstate->env->auth_zones->lock);
z = auth_zones_find_zone(qstate->env->auth_zones, delname, delnamelen,
qstate->qinfo.qclass);
if(!z) {
lock_rw_unlock(&qstate->env->auth_zones->lock);
return 1;
}
lock_rw_rdlock(&z->lock);
lock_rw_unlock(&qstate->env->auth_zones->lock);
if(z->for_upstream) {
if(iq->dp && query_dname_compare(z->name, iq->dp->name) == 0
&& iq->dp->auth_dp && qstate->blacklist &&
z->fallback_enabled) {
/* cache is blacklisted and fallback, and we
* already have an auth_zone dp */
if(verbosity>=VERB_ALGO) {
char buf[255+1];
dname_str(z->name, buf);
verbose(VERB_ALGO, "auth_zone %s "
"fallback because cache blacklisted",
buf);
}
lock_rw_unlock(&z->lock);
iq->dp = NULL;
return 1;
}
if(iq->dp==NULL || dname_subdomain_c(z->name, iq->dp->name)) {
struct delegpt* dp;
if(qstate->blacklist && z->fallback_enabled) {
/* cache is blacklisted because of a DNSSEC
* validation failure, and the zone allows
* fallback to the internet, query there. */
if(verbosity>=VERB_ALGO) {
char buf[255+1];
dname_str(z->name, buf);
verbose(VERB_ALGO, "auth_zone %s "
"fallback because cache blacklisted",
buf);
}
lock_rw_unlock(&z->lock);
return 1;
}
dp = (struct delegpt*)regional_alloc_zero(
qstate->region, sizeof(*dp));
if(!dp) {
log_err("alloc failure");
if(z->fallback_enabled) {
lock_rw_unlock(&z->lock);
return 1; /* just fallback */
}
lock_rw_unlock(&z->lock);
errinf(qstate, "malloc failure");
return 0;
}
dp->name = regional_alloc_init(qstate->region,
z->name, z->namelen);
if(!dp->name) {
log_err("alloc failure");
if(z->fallback_enabled) {
lock_rw_unlock(&z->lock);
return 1; /* just fallback */
}
lock_rw_unlock(&z->lock);
errinf(qstate, "malloc failure");
return 0;
}
dp->namelen = z->namelen;
dp->namelabs = z->namelabs;
dp->auth_dp = 1;
iq->dp = dp;
}
}
lock_rw_unlock(&z->lock);
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 addresses.
*
* @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; i<rep->rrset_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;
if(!can_have_last_resort(qstate->env, iq->dp->name, iq->dp->namelen,
iq->qchase.qclass, NULL))
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;
}
/* no need to get the NS record for DS, it is above the zonecut */
if(qstate->qinfo.qtype == LDNS_RR_TYPE_DS)
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;
if(iq->refetch_glue && iq->dp) {
delname = iq->dp->name;
delnamelen = iq->dp->namelen;
}
/* strip one label off of DS query to lookup higher for it */
if( (iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue)
&& !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 = NULL;
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);
errinf(qstate, "request has exceeded the maximum number "
"restarts (eg. indirections)");
if(iq->qchase.qname)
errinf_dname(qstate, "stop at", iq->qchase.qname);
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);
errinf(qstate, "request has exceeded the maximum dependency "
"depth (eg. nameserver lookup recursion)");
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);
}
/*
* If we are restricted by a forward-zone or a stub-zone, we
* can't re-fetch glue for this delegation point.
* we won’t try to re-fetch glue if the iq->dp is null.
*/
if (iq->refetch_glue &&
iq->dp &&
!can_have_last_resort(qstate->env, iq->dp->name,
iq->dp->namelen, iq->qchase.qclass, NULL)) {
iq->refetch_glue = 0;
}
/* 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 (iter_stub_fwd_no_cache(qstate, &iq->qchase)) {
/* Asked to not query cache. */
verbose(VERB_ALGO, "no-cache set, going to the network");
qstate->no_cache_lookup = 1;
qstate->no_cache_store = 1;
msg = NULL;
} else 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 if(!qstate->no_cache_lookup) {
msg = dns_cache_lookup(qstate->env, iq->qchase.qname,
iq->qchase.qname_len, iq->qchase.qtype,
iq->qchase.qclass, qstate->query_flags,
qstate->region, qstate->env->scratch, 0);
if(!msg && qstate->env->neg_cache &&
iter_qname_indicates_dnssec(qstate->env, &iq->qchase)) {
/* 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,
qstate->env->cfg);
}
/* 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)) {
errinf(qstate, "failed to prepend CNAME "
"components, malloc failure");
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);
if(qstate->env->cfg->qname_minimisation)
iq->minimisation_state = INIT_MINIMISE_STATE;
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);
if(FLAGS_GET_RCODE(msg->rep->flags) == LDNS_RCODE_SERVFAIL)
errinf(qstate, "SERVFAIL in cache");
/* 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");
errinf(qstate, "malloc failure for forward zone");
return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
}
iq->refetch_glue = 0;
iq->minimisation_state = DONOT_MINIMISE_STATE;
/* 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");
errinf(qstate, "malloc failure, for delegation info");
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
&& can_have_last_resort(qstate->env, delname, delnamelen, iq->qchase.qclass, NULL))) {
/* 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);
}
/* 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+qstate->prefetch_leeway);
else iq->dp = NULL;
/* If the cache has returned nothing, then we have a
* root priming situation. */
if(iq->dp == NULL) {
int r;
/* if under auth zone, no prime needed */
if(!auth_zone_delegpt(qstate, iq, delname, delnamelen))
return error_response(qstate, id,
LDNS_RCODE_SERVFAIL);
if(iq->dp) /* use auth zone dp */
return next_state(iq, INIT_REQUEST_2_STATE);
/* if there is a stub, then no root prime needed */
r = prime_stub(qstate, iq, id, delname,
iq->qchase.qclass);
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(qstate->env->hints,
iq->qchase.qclass);
if(!iq->dp) {
log_err("internal error: no hints dp");
errinf(qstate, "no hints for this class");
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");
errinf(qstate, "malloc failure, 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, 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;
}
if(!iq->ratelimit_ok && qstate->prefetch_leeway)
iq->ratelimit_ok = 1; /* allow prefetches, this keeps
otherwise valid data in the cache */
if(!iq->ratelimit_ok && infra_ratelimit_exceeded(
qstate->env->infra_cache, iq->dp->name,
iq->dp->namelen, *qstate->env->now)) {
/* and increment the rate, so that the rate for time
* now will also exceed the rate, keeping cache fresh */
(void)infra_ratelimit_inc(qstate->env->infra_cache,
iq->dp->name, iq->dp->namelen,
*qstate->env->now, &qstate->qinfo,
qstate->reply);
/* see if we are passed through with slip factor */
if(qstate->env->cfg->ratelimit_factor != 0 &&
ub_random_max(qstate->env->rnd,
qstate->env->cfg->ratelimit_factor) == 1) {
iq->ratelimit_ok = 1;
log_nametypeclass(VERB_ALGO, "ratelimit allowed through for "
"delegation point", iq->dp->name,
LDNS_RR_TYPE_NS, LDNS_RR_CLASS_IN);
} else {
lock_basic_lock(&ie->queries_ratelimit_lock);
ie->num_queries_ratelimited++;
lock_basic_unlock(&ie->queries_ratelimit_lock);
log_nametypeclass(VERB_ALGO, "ratelimit exceeded with "
"delegation point", iq->dp->name,
LDNS_RR_TYPE_NS, LDNS_RR_CLASS_IN);
qstate->was_ratelimited = 1;
errinf(qstate, "query was ratelimited");
errinf_dname(qstate, "for zone", iq->dp->name);
return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
}
}
/* 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)) {
struct delegpt* retdp = NULL;
if(!can_have_last_resort(qstate->env, iq->dp->name, iq->dp->namelen, iq->qchase.qclass, &retdp)) {
if(retdp) {
verbose(VERB_QUERY, "cache has stub "
"or fwd but no addresses, "
"fallback to config");
iq->dp = delegpt_copy(retdp,
qstate->region);
if(!iq->dp) {
log_err("out of memory in "
"stub/fwd fallback");
errinf(qstate, "malloc failure, for fallback to config");
return error_response(qstate,
id, LDNS_RCODE_SERVFAIL);
}
break;
}
verbose(VERB_ALGO, "useless dp "
"but cannot go up, servfail");
delegpt_log(VERB_ALGO, iq->dp);
errinf(qstate, "no useful nameservers, "
"and cannot go up");
errinf_dname(qstate, "for zone", iq->dp->name);
return error_response(qstate, id,
LDNS_RCODE_SERVFAIL);
}
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(qstate->env->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");
errinf(qstate, "malloc failure, in safety belt, for root");
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 primarily 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 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,
int id)
{
uint8_t* delname;
size_t delnamelen;
log_query_info(VERB_QUERY, "resolving (init part 2): ",
&qstate->qinfo);
delname = iq->qchase.qname;
delnamelen = iq->qchase.qname_len;
if(iq->refetch_glue) {
struct iter_hints_stub* stub;
if(!iq->dp) {
log_err("internal or malloc fail: no dp for refetch");
errinf(qstate, "malloc failure, no delegation info");
return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
}
/* Do not send queries above stub, do not set delname to dp if
* this is above stub without stub-first. */
stub = hints_lookup_stub(
qstate->env->hints, iq->qchase.qname, iq->qchase.qclass,
iq->dp);
if(!stub || !stub->dp->has_parent_side_NS ||
dname_subdomain_c(iq->dp->name, stub->dp->name)) {
delname = iq->dp->name;
delnamelen = iq->dp->namelen;
}
}
if(iq->qchase.qtype == LDNS_RR_TYPE_DS || iq->refetch_glue) {
if(!dname_is_root(delname))
dname_remove_label(&delname, &delnamelen);
iq->refetch_glue = 0; /* if CNAME causes restart, no refetch */
}
/* see if we have an auth zone to answer from, improves dp from cache
* (if any dp from cache) with auth zone dp, if that is lower */
if(!auth_zone_delegpt(qstate, iq, delname, delnamelen))
return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
/* Check to see if we need to prime a stub zone. */
if(prime_stub(qstate, iq, id, delname, iq->qchase.qclass)) {
/* 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->deleg_msg) {
iq->response = iq->deleg_msg;
if(verbosity >= VERB_ALGO && iq->response)
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+subq->prefetch_leeway);
/* 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;
if(iq->depth > 0 && iq->target_count &&
iq->target_count[1] > MAX_TARGET_COUNT) {
char s[LDNS_MAX_DOMAINLEN+1];
dname_str(qstate->qinfo.qname, s);
verbose(VERB_QUERY, "request %s has exceeded the maximum "
"number of glue fetches %d", s, iq->target_count[1]);
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(!can_have_last_resort(qstate->env, iq->dp->name, iq->dp->namelen,
iq->qchase.qclass, NULL)) {
/* fail -- no more targets, no more hope of targets, no hope
* of a response. */
errinf(qstate, "all the configured stub or forward servers failed,");
errinf_dname(qstate, "at zone", iq->dp->name);
verbose(VERB_QUERY, "configured stub or forward servers failed -- returning SERVFAIL");
return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
}
if(!iq->dp->has_parent_side_NS && dname_is_root(iq->dp->name)) {
struct delegpt* p = hints_lookup_root(qstate->env->hints,
iq->qchase.qclass);
if(p) {
struct delegpt_addr* a;
iq->chase_flags &= ~BIT_RD; /* go to authorities */
for(ns = p->nslist; ns; ns=ns->next) {
(void)delegpt_add_ns(iq->dp, qstate->region,
ns->name, ns->lame);
}
for(a = p->target_list; a; a=a->next_target) {
(void)delegpt_add_addr(iq->dp, qstate->region,
&a->addr, a->addrlen, a->bogus,
a->lame, a->tls_auth_name);
}
}
iq->dp->has_parent_side_NS = 1;
} else 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->chase_flags &= ~BIT_RD; /* go to authorities */
iq->deleg_msg = NULL;
iq->refetch_glue = 1;
iq->query_restart_count++;
iq->sent_count = 0;
if(qstate->env->cfg->qname_minimisation)
iq->minimisation_state = INIT_MINIMISE_STATE;
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)) {
errinf(qstate, "could not fetch nameserver");
errinf_dname(qstate, "at zone", iq->dp->name);
return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
}
iq->num_target_queries += qs;
target_count_increase(iq, 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");
errinf(qstate, "cannot fetch more nameservers because at max dependency depth");
return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
}
if(iq->depth > 0 && iq->target_count &&
iq->target_count[1] > MAX_TARGET_COUNT) {
char s[LDNS_MAX_DOMAINLEN+1];
dname_str(qstate->qinfo.qname, s);
verbose(VERB_QUERY, "request %s has exceeded the maximum "
"number of glue fetches %d", s, iq->target_count[1]);
errinf(qstate, "exceeded the maximum number of glue fetches");
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) {
/* if this nameserver is at a delegation point, but that
* delegation point is a stub and we cannot go higher, skip*/
if( ((ie->supports_ipv6 && !ns->done_pside6) ||
(ie->supports_ipv4 && !ns->done_pside4)) &&
!can_have_last_resort(qstate->env, ns->name, ns->namelen,
iq->qchase.qclass, NULL)) {
log_nametypeclass(VERB_ALGO, "cannot pside lookup ns "
"because it is also a stub/forward,",
ns->name, LDNS_RR_TYPE_NS, iq->qchase.qclass);
if(ie->supports_ipv6) ns->done_pside6 = 1;
if(ie->supports_ipv4) ns->done_pside4 = 1;
continue;
}
/* 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)) {
errinf_dname(qstate, "could not generate nameserver AAAA lookup for", ns->name);
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)) {
errinf_dname(qstate, "could not generate nameserver A lookup for", ns->name);
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;
target_count_increase(iq, 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(!qstate->no_cache_store && 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));
errinf(qstate, "all servers for this domain failed,");
errinf_dname(qstate, "at zone", iq->dp->name);
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);
}
/**
* Try to find the NS record set that will resolve a qtype DS query. Due
* to grandparent/grandchild reasons we did not get a proper lookup right
* away. We need to create type NS queries until we get the right parent
* for this lookup. We remove labels from the query to find the right point.
* If we end up at the old dp name, then there is no solution.
*
* @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
processDSNSFind(struct module_qstate* qstate, struct iter_qstate* iq, int id)
{
struct module_qstate* subq = NULL;
verbose(VERB_ALGO, "processDSNSFind");
if(!iq->dsns_point) {
/* initialize */
iq->dsns_point = iq->qchase.qname;
iq->dsns_point_len = iq->qchase.qname_len;
}
/* robustcheck for internal error: we are not underneath the dp */
if(!dname_subdomain_c(iq->dsns_point, iq->dp->name)) {
errinf_dname(qstate, "for DS query parent-child nameserver search the query is not under the zone", iq->dp->name);
return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
}
/* go up one (more) step, until we hit the dp, if so, end */
dname_remove_label(&iq->dsns_point, &iq->dsns_point_len);
if(query_dname_compare(iq->dsns_point, iq->dp->name) == 0) {
/* there was no inbetween nameserver, use the old delegation
* point again. And this time, because dsns_point is nonNULL
* we are going to accept the (bad) result */
iq->state = QUERYTARGETS_STATE;
return 1;
}
iq->state = DSNS_FIND_STATE;
/* spawn NS lookup (validation not needed, this is for DS lookup) */
log_nametypeclass(VERB_ALGO, "fetch nameservers",
iq->dsns_point, LDNS_RR_TYPE_NS, iq->qchase.qclass);
if(!generate_sub_request(iq->dsns_point, iq->dsns_point_len,
LDNS_RR_TYPE_NS, iq->qchase.qclass, qstate, id, iq,
INIT_REQUEST_STATE, FINISHED_STATE, &subq, 0)) {
errinf_dname(qstate, "for DS query parent-child nameserver search, could not generate NS lookup for", iq->dsns_point);
return error_response_cache(qstate, id, LDNS_RCODE_SERVFAIL);
}
return 0;
}
/**
* 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;
int auth_fallback = 0;
uint8_t* qout_orig = NULL;
size_t qout_orig_len = 0;
/* 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);
errinf(qstate, "exceeded the maximum of referrals");
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);
errinf(qstate, "exceeded the maximum number of sends");
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");
errinf(qstate, "failed to get a delegation (eg. prime failure)");
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;
}
if(iq->minimisation_state == INIT_MINIMISE_STATE
&& !(iq->chase_flags & BIT_RD)) {
/* (Re)set qinfo_out to (new) delegation point, except when
* qinfo_out is already a subdomain of dp. This happens when
* increasing by more than one label at once (QNAMEs with more
* than MAX_MINIMISE_COUNT labels). */
if(!(iq->qinfo_out.qname_len
&& dname_subdomain_c(iq->qchase.qname,
iq->qinfo_out.qname)
&& dname_subdomain_c(iq->qinfo_out.qname,
iq->dp->name))) {
iq->qinfo_out.qname = iq->dp->name;
iq->qinfo_out.qname_len = iq->dp->namelen;
iq->qinfo_out.qtype = LDNS_RR_TYPE_A;
iq->qinfo_out.qclass = iq->qchase.qclass;
iq->qinfo_out.local_alias = NULL;
iq->minimise_count = 0;
}
iq->minimisation_state = MINIMISE_STATE;
}
if(iq->minimisation_state == MINIMISE_STATE) {
int qchaselabs = dname_count_labels(iq->qchase.qname);
int labdiff = qchaselabs -
dname_count_labels(iq->qinfo_out.qname);
qout_orig = iq->qinfo_out.qname;
qout_orig_len = iq->qinfo_out.qname_len;
iq->qinfo_out.qname = iq->qchase.qname;
iq->qinfo_out.qname_len = iq->qchase.qname_len;
iq->minimise_count++;
iq->minimise_timeout_count = 0;
iter_dec_attempts(iq->dp, 1);
/* Limit number of iterations for QNAMEs with more
* than MAX_MINIMISE_COUNT labels. Send first MINIMISE_ONE_LAB
* labels of QNAME always individually.
*/
if(qchaselabs > MAX_MINIMISE_COUNT && labdiff > 1 &&
iq->minimise_count > MINIMISE_ONE_LAB) {
if(iq->minimise_count < MAX_MINIMISE_COUNT) {
int multilabs = qchaselabs - 1 -
MINIMISE_ONE_LAB;
int extralabs = multilabs /
MINIMISE_MULTIPLE_LABS;
if (MAX_MINIMISE_COUNT - iq->minimise_count >=
multilabs % MINIMISE_MULTIPLE_LABS)
/* Default behaviour is to add 1 label
* every iteration. Therefore, decrement
* the extralabs by 1 */
extralabs--;
if (extralabs < labdiff)
labdiff -= extralabs;
else
labdiff = 1;
}
/* Last minimised iteration, send all labels with
* QTYPE=NS */
else
labdiff = 1;
}
if(labdiff > 1) {
verbose(VERB_QUERY, "removing %d labels", labdiff-1);
dname_remove_labels(&iq->qinfo_out.qname,
&iq->qinfo_out.qname_len,
labdiff-1);
}
if(labdiff < 1 || (labdiff < 2
&& (iq->qchase.qtype == LDNS_RR_TYPE_DS
|| iq->qchase.qtype == LDNS_RR_TYPE_A)))
/* Stop minimising this query, resolve "as usual" */
iq->minimisation_state = DONOT_MINIMISE_STATE;
else if(!qstate->no_cache_lookup) {
struct dns_msg* msg = dns_cache_lookup(qstate->env,
iq->qinfo_out.qname, iq->qinfo_out.qname_len,
iq->qinfo_out.qtype, iq->qinfo_out.qclass,
qstate->query_flags, qstate->region,
qstate->env->scratch, 0);
if(msg && msg->rep->an_numrrsets == 0
&& FLAGS_GET_RCODE(msg->rep->flags) ==
LDNS_RCODE_NOERROR)
/* no need to send query if it is already
* cached as NOERROR/NODATA */
return 1;
}
}
if(iq->minimisation_state == SKIP_MINIMISE_STATE) {
if(iq->minimise_timeout_count < MAX_MINIMISE_TIMEOUT_COUNT)
/* Do not increment qname, continue incrementing next
* iteration */
iq->minimisation_state = MINIMISE_STATE;
else if(!qstate->env->cfg->qname_minimisation_strict)
/* Too many time-outs detected for this QNAME and QTYPE.
* We give up, disable QNAME minimisation. */
iq->minimisation_state = DONOT_MINIMISE_STATE;
}
if(iq->minimisation_state == DONOT_MINIMISE_STATE)
iq->qinfo_out = iq->qchase;
/* now find an answer to this query */
/* see if authority zones have an answer */
/* now we know the dp, we can check the auth zone for locally hosted
* contents */
if(!iq->auth_zone_avoid && qstate->blacklist) {
if(auth_zones_can_fallback(qstate->env->auth_zones,
iq->dp->name, iq->dp->namelen, iq->qinfo_out.qclass)) {
/* if cache is blacklisted and this zone allows us
* to fallback to the internet, then do so, and
* fetch results from the internet servers */
iq->auth_zone_avoid = 1;
}
}
if(iq->auth_zone_avoid) {
iq->auth_zone_avoid = 0;
auth_fallback = 1;
} else if(auth_zones_lookup(qstate->env->auth_zones, &iq->qinfo_out,
qstate->region, &iq->response, &auth_fallback, iq->dp->name,
iq->dp->namelen)) {
/* use this as a response to be processed by the iterator */
if(verbosity >= VERB_ALGO) {
log_dns_msg("msg from auth zone",
&iq->response->qinfo, iq->response->rep);
}
if((iq->chase_flags&BIT_RD) && !(iq->response->rep->flags&BIT_AA)) {
verbose(VERB_ALGO, "forwarder, ignoring referral from auth zone");
} else {
lock_rw_wrlock(&qstate->env->auth_zones->lock);
qstate->env->auth_zones->num_query_up++;
lock_rw_unlock(&qstate->env->auth_zones->lock);
iq->num_current_queries++;
iq->chase_to_rd = 0;
iq->dnssec_lame_query = 0;
iq->auth_zone_response = 1;
return next_state(iq, QUERY_RESP_STATE);
}
}
iq->auth_zone_response = 0;
if(auth_fallback == 0) {
/* like we got servfail from the auth zone lookup, and
* no internet fallback */
verbose(VERB_ALGO, "auth zone lookup failed, no fallback,"
" servfail");
errinf(qstate, "auth zone lookup failed, fallback is off");
return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
}
if(iq->dp->auth_dp) {
/* we wanted to fallback, but had no delegpt, only the
* auth zone generated delegpt, create an actual one */
iq->auth_zone_avoid = 1;
return next_state(iq, INIT_REQUEST_STATE);
}
/* but mostly, fallback==1 (like, when no such auth zone exists)
* and we continue with lookups */
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)) {
errinf(qstate, "could not fetch nameservers for 0x20 fallback");
return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
}
iq->num_target_queries += extra;
target_count_increase(iq, 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;
/* undo qname minimise step because we'll get back here
* to do it again */
if(qout_orig && iq->minimise_count > 0) {
iq->minimise_count--;
iq->qinfo_out.qname = qout_orig;
iq->qinfo_out.qname_len = qout_orig_len;
}
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*2+2 >= MAX_SENT_COUNT) {
/* *2 on sentcount check because ipv6 may fail */
/* 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->response = iq->caps_response;
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;
target_count_increase(iq, 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,
qstate->prefetch_leeway);
/* 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)) {
errinf(qstate, "could not fetch nameserver");
errinf_dname(qstate, "at zone", iq->dp->name);
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;
target_count_increase(iq, qs);
}
/* Since a target query might have been made, we
* need to check again. */
if(iq->num_target_queries == 0) {
/* if in capsforid fallback, instead of last
* resort, we agree with the current reply
* we have (if any) (our count of addrs bad)*/
if(iq->caps_fallback && iq->caps_reply) {
/* we're done, process the response */
verbose(VERB_ALGO, "0x20 fallback had %d responses, "
"but no more servers except "
"last resort, done.",
(int)iq->caps_server+1);
iq->response = iq->caps_response;
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;
}
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;
}
/* undo qname minimise step because we'll get back here
* to do it again */
if(qout_orig && iq->minimise_count > 0) {
iq->minimise_count--;
iq->qinfo_out.qname = qout_orig;
iq->qinfo_out.qname_len = qout_orig_len;
}
return 0;
}
/* if not forwarding, check ratelimits per delegationpoint name */
if(!(iq->chase_flags & BIT_RD) && !iq->ratelimit_ok) {
if(!infra_ratelimit_inc(qstate->env->infra_cache, iq->dp->name,
iq->dp->namelen, *qstate->env->now, &qstate->qinfo,
qstate->reply)) {
lock_basic_lock(&ie->queries_ratelimit_lock);
ie->num_queries_ratelimited++;
lock_basic_unlock(&ie->queries_ratelimit_lock);
verbose(VERB_ALGO, "query exceeded ratelimits");
qstate->was_ratelimited = 1;
errinf_dname(qstate, "exceeded ratelimit for zone",
iq->dp->name);
return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
}
}
/* We have a valid target. */
if(verbosity >= VERB_QUERY) {
log_query_info(VERB_QUERY, "sending query:", &iq->qinfo_out);
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->qinfo_out,
iq->chase_flags | (iq->chase_to_rd?BIT_RD:0),
/* unset CD if to forwarder(RD set) and not dnssec retry
* (blacklist nonempty) and no trust-anchors are configured
* above the qname or on the first attempt when dnssec is on */
EDNS_DO| ((iq->chase_to_rd||(iq->chase_flags&BIT_RD)!=0)&&
!qstate->blacklist&&(!iter_qname_indicates_dnssec(qstate->env,
&iq->qinfo_out)||target->attempts==1)?0:BIT_CD),
iq->dnssec_expected, iq->caps_fallback || is_caps_whitelisted(
ie, iq), &target->addr, target->addrlen,
iq->dp->name, iq->dp->namelen,
(iq->dp->ssl_upstream || qstate->env->cfg->ssl_upstream),
target->tls_auth_name, qstate);
if(!outq) {
log_addr(VERB_DETAIL, "error sending query to auth server",
&target->addr, target->addrlen);
if(!(iq->chase_flags & BIT_RD) && !iq->ratelimit_ok)
infra_ratelimit_dec(qstate->env->infra_cache, iq->dp->name,
iq->dp->namelen, *qstate->env->now);
if(qstate->env->cfg->qname_minimisation)
iq->minimisation_state = SKIP_MINIMISE_STATE;
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; i<to; i++) {
if(ntohs(rep->rrsets[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(!inplace_cb_query_response_call(qstate->env, qstate, iq->response))
log_err("unable to call query_response callback");
if(iq->response == NULL) {
/* Don't increment qname when QNAME minimisation is enabled */
if(qstate->env->cfg->qname_minimisation) {
iq->minimise_timeout_count++;
iq->minimisation_state = SKIP_MINIMISE_STATE;
}
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->qinfo_out, iq->dp);
iq->chase_to_rd = 0;
if(type == RESPONSE_TYPE_REFERRAL && (iq->chase_flags&BIT_RD) &&
!iq->auth_zone_response) {
/* When forwarding (RD bit is set), we handle referrals
* differently. No queries should be sent elsewhere */
type = RESPONSE_TYPE_ANSWER;
}
if(!qstate->env->cfg->disable_dnssec_lame_check && iq->dnssec_expected
&& !iq->dnssec_lame_query &&
!(iq->chase_flags&BIT_RD)
&& iq->sent_count < DNSSEC_LAME_DETECT_COUNT
&& 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 */
if(!iter_msg_has_dnssec(iq->response)) {
/* Mark this address as dnsseclame in this dp,
* because that will make serverselection disprefer
* it, but also, once it is the only final option,
* use dnssec-lame-bypass if it needs to query there.*/
if(qstate->reply) {
struct delegpt_addr* a = delegpt_find_addr(
iq->dp, &qstate->reply->addr,
qstate->reply->addrlen);
if(a) a->dnsseclame = 1;
}
/* test 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_from_zone(iq->response, iq->dp, type,
iq->qchase.qclass))
qstate->reply = NULL;
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);
if(type == RESPONSE_TYPE_THROWAWAY &&
FLAGS_GET_RCODE(iq->response->rep->flags) == LDNS_RCODE_YXDOMAIN) {
/* YXDOMAIN is a permanent error, no need to retry */
type = RESPONSE_TYPE_ANSWER;
}
if(type == RESPONSE_TYPE_CNAME && iq->response->rep->an_numrrsets >= 1
&& ntohs(iq->response->rep->rrsets[0]->rk.type) == LDNS_RR_TYPE_DNAME) {
uint8_t* sname = NULL;
size_t snamelen = 0;
get_cname_target(iq->response->rep->rrsets[0], &sname,
&snamelen);
if(snamelen && dname_subdomain_c(sname, iq->response->rep->rrsets[0]->rk.dname)) {
/* DNAME to a subdomain loop; do not recurse */
type = RESPONSE_TYPE_ANSWER;
}
} else if(type == RESPONSE_TYPE_CNAME &&
iq->qchase.qtype == LDNS_RR_TYPE_CNAME &&
iq->minimisation_state == MINIMISE_STATE &&
query_dname_compare(iq->qchase.qname, iq->qinfo_out.qname) == 0) {
/* The minimised query for full QTYPE and hidden QTYPE can be
* classified as CNAME response type, even when the original
* QTYPE=CNAME. This should be treated as answer response type.
*/
type = RESPONSE_TYPE_ANSWER;
}
/* 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 qtype is DS, check we have the right level of answer,
* like grandchild answer but we need the middle, reject it */
if(iq->qchase.qtype == LDNS_RR_TYPE_DS && !iq->dsns_point
&& !(iq->chase_flags&BIT_RD)
&& iter_ds_toolow(iq->response, iq->dp)
&& iter_dp_cangodown(&iq->qchase, iq->dp)) {
/* 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;
return processDSNSFind(qstate, iq, id);
}
if(!qstate->no_cache_store)
iter_dns_store(qstate->env, &iq->response->qinfo,
iq->response->rep, 0, qstate->prefetch_leeway,
iq->dp&&iq->dp->has_parent_side_NS,
qstate->region, qstate->query_flags);
/* 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);
if(iq->minimisation_state != DONOT_MINIMISE_STATE
&& !(iq->chase_flags & BIT_RD)) {
if(FLAGS_GET_RCODE(iq->response->rep->flags) !=
LDNS_RCODE_NOERROR) {
if(qstate->env->cfg->qname_minimisation_strict) {
if(FLAGS_GET_RCODE(iq->response->rep->flags) ==
LDNS_RCODE_NXDOMAIN) {
iter_scrub_nxdomain(iq->response);
return final_state(iq);
}
return error_response(qstate, id,
LDNS_RCODE_SERVFAIL);
}
/* Best effort qname-minimisation.
* Stop minimising and send full query when
* RCODE is not NOERROR. */
iq->minimisation_state = DONOT_MINIMISE_STATE;
}
if(FLAGS_GET_RCODE(iq->response->rep->flags) ==
LDNS_RCODE_NXDOMAIN) {
/* Stop resolving when NXDOMAIN is DNSSEC
* signed. Based on assumption that nameservers
* serving signed zones do not return NXDOMAIN
* for empty-non-terminals. */
if(iq->dnssec_expected)
return final_state(iq);
/* Make subrequest to validate intermediate
* NXDOMAIN if harden-below-nxdomain is
* enabled. */
if(qstate->env->cfg->harden_below_nxdomain) {
struct module_qstate* subq = NULL;
log_query_info(VERB_QUERY,
"schedule NXDOMAIN validation:",
&iq->response->qinfo);
if(!generate_sub_request(
iq->response->qinfo.qname,
iq->response->qinfo.qname_len,
iq->response->qinfo.qtype,
iq->response->qinfo.qclass,
qstate, id, iq,
INIT_REQUEST_STATE,
FINISHED_STATE, &subq, 1))
verbose(VERB_ALGO,
"could not validate NXDOMAIN "
"response");
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;
}
}
return next_state(iq, QUERYTARGETS_STATE);
}
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(!(iq->chase_flags & BIT_RD) && !iq->ratelimit_ok) {
/* we have a referral, no ratelimit, we can send
* our queries to the given name */
infra_ratelimit_dec(qstate->env->infra_cache,
iq->dp->name, iq->dp->namelen,
*qstate->env->now);
}
/* if hardened, only store referral if we asked for it */
if(!qstate->no_cache_store &&
(!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 */
iter_dns_store(qstate->env, &iq->response->qinfo,
iq->response->rep, 1, 0, 0, NULL, 0);
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(!qstate->no_cache_store && 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 (qstate->env->cfg->qname_minimisation)
iq->minimisation_state = INIT_MINIMISE_STATE;
if(!iq->dp) {
errinf(qstate, "malloc failure, for delegation point");
return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
}
if(!cache_fill_missing(qstate->env, iq->qchase.qclass,
qstate->region, iq->dp)) {
errinf(qstate, "malloc failure, copy extra info into delegation point");
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);
/* if qtype is DS, check we have the right level of answer,
* like grandchild answer but we need the middle, reject it */
if(iq->qchase.qtype == LDNS_RR_TYPE_DS && !iq->dsns_point
&& !(iq->chase_flags&BIT_RD)
&& iter_ds_toolow(iq->response, iq->dp)
&& iter_dp_cangodown(&iq->qchase, iq->dp)) {
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;
return processDSNSFind(qstate, iq, id);
}
/* Process the CNAME response. */
if(!handle_cname_response(qstate, iq, iq->response,
&sname, &snamelen)) {
errinf(qstate, "malloc failure, CNAME info");
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(!qstate->no_cache_store)
iter_dns_store(qstate->env, &iq->response->qinfo,
iq->response->rep, 1, qstate->prefetch_leeway,
iq->dp&&iq->dp->has_parent_side_NS, NULL,
qstate->query_flags);
/* 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;
iq->dsns_point = NULL;
iq->auth_zone_response = 0;
iq->sent_count = 0;
if(iq->minimisation_state != MINIMISE_STATE)
/* Only count as query restart when it is not an extra
* query as result of qname minimisation. */
iq->query_restart_count++;
if(qstate->env->cfg->qname_minimisation)
iq->minimisation_state = INIT_MINIMISE_STATE;
/* 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 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. */
if (qstate->env->cfg->qname_minimisation &&
!qstate->env->cfg->qname_minimisation_strict)
iq->minimisation_state = DONOT_MINIMISE_STATE;
if(iq->auth_zone_response) {
/* can we fallback? */
iq->auth_zone_response = 0;
if(!auth_zones_can_fallback(qstate->env->auth_zones,
iq->dp->name, iq->dp->namelen, qstate->qinfo.qclass)) {
verbose(VERB_ALGO, "auth zone response bad, and no"
" fallback possible, servfail");
errinf_dname(qstate, "response is bad, no fallback, "
"for auth zone", iq->dp->name);
return error_response(qstate, id, LDNS_RCODE_SERVFAIL);
}
verbose(VERB_ALGO, "auth zone response was bad, "
"fallback enabled");
iq->auth_zone_avoid = 1;
if(iq->dp->auth_dp) {
/* we are using a dp for the auth zone, with no
* nameservers, get one first */
iq->dp = NULL;
return next_state(iq, INIT_REQUEST_STATE);
}
}
return next_state(iq, QUERYTARGETS_STATE);
}
/**
* Return priming query results to interested 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 {
errinf(qstate, "prime response did not get an answer");
errinf_dname(qstate, "for", qstate->qinfo.qname);
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 reactivating 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);
/* Tell the originating event that this target query has finished
* (regardless if it succeeded or not). */
foriq->num_target_queries--;
/* 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;
}
/* 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, 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,
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 DS NS Find queries, that attempt to find the delegation
* point where we ask the DS query from.
*
* @param qstate: query state.
* @param id: module id.
* @param forq: super query state.
*/
static void
processDSNSResponse(struct module_qstate* qstate, int id,
struct module_qstate* forq)
{
struct iter_qstate* foriq = (struct iter_qstate*)forq->minfo[id];
/* if the finished (iq->response) query has no NS set: continue
* up to look for the right dp; nothing to change, do DPNSstate */
if(qstate->return_rcode != LDNS_RCODE_NOERROR)
return; /* seek further */
/* find the NS RRset (without allowing CNAMEs) */
if(!reply_find_rrset(qstate->return_msg->rep, qstate->qinfo.qname,
qstate->qinfo.qname_len, LDNS_RR_TYPE_NS,
qstate->qinfo.qclass)){
return; /* seek further */
}
/* else, store as DP and continue at querytargets */
foriq->state = QUERYTARGETS_STATE;
foriq->dp = delegpt_from_message(qstate->return_msg, forq->region);
if(!foriq->dp) {
log_err("out of memory in dsns dp alloc");
errinf(qstate, "malloc failure, in DS search");
return; /* dp==NULL in QUERYTARGETS makes SERVFAIL */
}
/* success, go query the querytargets in the new dp (and go down) */
}
/**
* 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 */
if(from->rep->rrset_count > RR_COUNT_MAX ||
to->rep->rrset_count > RR_COUNT_MAX) {
log_err("malloc failed (too many rrsets) in collect ANY");
foriq->state = FINISHED_STATE;
return; /* integer overflow protection */
}
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;
if(from->rep->serve_expired_ttl < to->rep->serve_expired_ttl)
to->rep->serve_expired_ttl = from->rep->serve_expired_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 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(qstate->env->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))) {
errinf(qstate, "could not generate class ANY"
" lookup query");
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(!qstate->no_cache_store && 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");
errinf(qstate, "(no response found at query finish)");
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->no_cache_store && qstate->query_flags&BIT_RD) {
iter_dns_store(qstate->env, &qstate->qinfo,
iq->response->rep, 0, qstate->prefetch_leeway,
iq->dp&&iq->dp->has_parent_side_NS,
qstate->region, qstate->query_flags);
}
}
qstate->return_rcode = LDNS_RCODE_NOERROR;
qstate->return_msg = iq->response;
return 0;
}
/*
* Return priming query results to interested 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(super->qinfo.qtype == LDNS_RR_TYPE_DS && ((struct iter_qstate*)
super->minfo[id])->state == DSNS_FIND_STATE)
processDSNSResponse(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, 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 DSNS_FIND_STATE:
cont = processDSNSFind(qstate, iq, 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;
sldns_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) {
if(event == module_event_noreply && iq->sent_count >= 3 &&
qstate->env->cfg->use_caps_bits_for_id &&
!iq->caps_fallback && !is_caps_whitelisted(ie, iq)) {
/* start fallback */
iq->caps_fallback = 1;
iq->caps_server = 0;
iq->caps_reply = NULL;
iq->caps_response = NULL;
iq->caps_minimisation_state = DONOT_MINIMISE_STATE;
iq->state = QUERYTARGETS_STATE;
iq->num_current_queries--;
/* need fresh attempts for the 0x20 fallback, if
* that was the cause for the failure */
iter_dec_attempts(iq->dp, 3);
verbose(VERB_DETAIL, "Capsforid: timeouts, starting fallback");
goto handle_it;
}
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);
errinf(qstate, "module iterator received wrong internal event with a response message");
(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;
sldns_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, qstate->env->scratch) !=
LDNS_RCODE_NOERROR)
goto handle_it;
/* Copy the edns options we may got from the back end */
if(edns.opt_list) {
qstate->edns_opts_back_in = edns_opt_copy_region(edns.opt_list,
qstate->region);
if(!qstate->edns_opts_back_in) {
log_err("out of memory on incoming message");
/* like packet got dropped */
goto handle_it;
}
if(!inplace_cb_edns_back_parsed_call(qstate->env, qstate)) {
log_err("unable to call edns_back_parsed callback");
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->qinfo_out, iq->dp->name,
qstate->env->scratch, qstate->env, ie)) {
/* if 0x20 enabled, start fallback, but we have no message */
if(event == module_event_capsfail && !iq->caps_fallback) {
iq->caps_fallback = 1;
iq->caps_server = 0;
iq->caps_reply = NULL;
iq->caps_response = NULL;
iq->caps_minimisation_state = DONOT_MINIMISE_STATE;
iq->state = QUERYTARGETS_STATE;
iq->num_current_queries--;
verbose(VERB_DETAIL, "Capsforid: scrub failed, starting fallback with no response");
}
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 || iq->caps_fallback) {
if(qstate->env->cfg->qname_minimisation &&
iq->minimisation_state != DONOT_MINIMISE_STATE) {
/* Skip QNAME minimisation for next query, since that
* one has to match the current query. */
iq->minimisation_state = SKIP_MINIMISE_STATE;
}
/* for fallback we care about main answer, not additionals */
/* removing that makes comparison more likely to succeed */
caps_strip_reply(iq->response->rep);
if(iq->caps_fallback &&
iq->caps_minimisation_state != iq->minimisation_state) {
/* QNAME minimisation state has changed, restart caps
* fallback. */
iq->caps_fallback = 0;
}
if(!iq->caps_fallback) {
/* start fallback */
iq->caps_fallback = 1;
iq->caps_server = 0;
iq->caps_reply = iq->response->rep;
iq->caps_response = iq->response;
iq->caps_minimisation_state = iq->minimisation_state;
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(!iq->caps_reply) {
iq->caps_reply = iq->response->rep;
iq->caps_response = iq->response;
iq->caps_server = -1; /*become zero at ++,
so that we start the full set of trials */
} else if(caps_failed_rcode(iq->caps_reply) &&
!caps_failed_rcode(iq->response->rep)) {
/* prefer to upgrade to non-SERVFAIL */
iq->caps_reply = iq->response->rep;
iq->caps_response = iq->response;
} else if(!caps_failed_rcode(iq->caps_reply) &&
caps_failed_rcode(iq->response->rep)) {
/* if we have non-SERVFAIL as answer then
* we can ignore SERVFAILs for the equality
* comparison */
/* no instructions here, skip other else */
} else if(caps_failed_rcode(iq->caps_reply) &&
caps_failed_rcode(iq->response->rep)) {
/* failure is same as other failure in fallbk*/
/* no instructions here, skip other else */
} else if(!reply_equal(iq->response->rep, iq->caps_reply,
qstate->env->scratch)) {
verbose(VERB_DETAIL, "Capsforid fallback: "
"getting different replies, failed");
outbound_list_remove(&iq->outlist, outbound);
errinf(qstate, "0x20 failed, then got different replies in fallback");
(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)) {
errinf(qstate, "malloc failure, new iterator module allocation");
(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");
errinf(qstate, "iterator module got the error event");
(void)error_response(qstate, id, LDNS_RCODE_SERVFAIL);
return;
}
log_err("bad event for iterator");
errinf(qstate, "iterator module received wrong event");
(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);
if(iq->target_count && --iq->target_count[0] == 0)
free(iq->target_count);
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)
+ 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 DSNS_FIND_STATE :
return "DSNS FIND 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;
}