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Start with SVCB AliasMode processing #1109

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Start with SVCB AliasMode processing #1109

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99 changes: 99 additions & 0 deletions iterator/iterator.c
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Original file line number Diff line number Diff line change
Expand Up @@ -575,6 +575,63 @@ handle_cname_response(struct module_qstate* qstate, struct iter_qstate* iq,
return 1;
}

static int
get_svcb_alias_target(struct ub_packed_rrset_key* r,
uint8_t** mname, size_t* mname_len)
{
size_t i;
struct packed_rrset_data* d = (struct packed_rrset_data*)r->entry.data;
(void)r; (void)mname; (void)mname_len;

for(i=0; i<d->count; i++) {
size_t t_len; /* TargetName length */

if(d->rr_len[i] <= 5
|| ((uint16_t*)d->rr_data[i])[1] != 0
|| !(t_len = dname_valid(d->rr_data[i] + 4, d->rr_len[i] - 4)))
continue;
*mname = d->rr_data[i] + 4;
*mname_len = t_len;
return 1;
}
return 0;
}

static int
handle_svcb_alias(struct module_qstate* qstate, struct iter_qstate* iq,
struct dns_msg* msg, uint8_t** mname, size_t* mname_len)
{
int new_target = 0;
size_t i;
(void)qstate;(void)iq;(void)msg;(void)mname;(void)mname_len;

assert(iq->qchase.qtype == LDNS_RR_TYPE_SVCB
|| iq->qchase.qtype == LDNS_RR_TYPE_HTTPS);
/* Start with the (current) qname. */
*mname = iq->qchase.qname;
*mname_len = iq->qchase.qname_len;

/* Iterate over the ANSWER rrsets in order, looking for SVCB or HTTPS
*
*/
for(i=0; i<msg->rep->an_numrrsets; i++) {
struct ub_packed_rrset_key* r = msg->rep->rrsets[i];

if(ntohs(r->rk.type) == iq->qchase.qtype
&& query_dname_compare(*mname, r->rk.dname) == 0
&& get_svcb_alias_target(r, mname, mname_len)
&& !iter_find_rrset_in_prepend_answer(iq, r)) {
/* Add this relevant SVCB rrset to the prepend list.*/
if(!iter_add_prepend_answer(qstate, iq, r))
return 0;
else
new_target = 1;
}
/* Other rrsets in the section are ignored. */
}
return new_target;
}

/** fill fail address for later recovery */
static void
fill_fail_addr(struct iter_qstate* iq, struct sockaddr_storage* addr,
Expand Down Expand Up @@ -3226,6 +3283,9 @@ processQueryResponse(struct module_qstate* qstate, struct iter_qstate* iq,

/* handle each of the type cases */
if(type == RESPONSE_TYPE_ANSWER) {
uint8_t* sname = NULL;
size_t snamelen = 0;

/* ANSWER type responses terminate the query algorithm,
* so they sent on their */
if(verbosity >= VERB_DETAIL) {
Expand Down Expand Up @@ -3258,6 +3318,45 @@ processQueryResponse(struct module_qstate* qstate, struct iter_qstate* iq,
iq->dp&&iq->dp->has_parent_side_NS,
qstate->region, qstate->query_flags,
qstate->qstarttime);
if(( iq->qchase.qtype == LDNS_RR_TYPE_SVCB
|| iq->qchase.qtype == LDNS_RR_TYPE_HTTPS)
&& handle_svcb_alias(qstate, iq, iq->response, &sname, &snamelen)) {

/* 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;
iq->dp_target_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->remote_addr,
qstate->reply->remote_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);
}
/* close down outstanding requests to be discarded */
outbound_list_clear(&iq->outlist);
iq->num_current_queries = 0;
Expand Down