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/* Copyright (C) 2017 Fastly, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <netinet/in.h>
#include "knot/include/module.h"
static knotd_in_state_t whoami_query(knotd_in_state_t state, knot_pkt_t *pkt,
knotd_qdata_t *qdata, knotd_mod_t *mod)
{
assert(pkt && qdata);
const knot_dname_t *zone_name = knotd_qdata_zone_name(qdata);
if (zone_name == NULL) {
return KNOTD_IN_STATE_ERROR;
}
/* Retrieve the query tuple. */
const knot_dname_t *qname = knot_pkt_qname(qdata->query);
const uint16_t qtype = knot_pkt_qtype(qdata->query);
const uint16_t qclass = knot_pkt_qclass(qdata->query);
/* We only generate A and AAAA records, which are Internet class. */
if (qclass != KNOT_CLASS_IN) {
return state;
}
/* Only handle queries with qname set to the zone name. */
if (!knot_dname_is_equal(qname, zone_name)) {
return state;
}
/* Only handle A and AAAA queries. */
if (qtype != KNOT_RRTYPE_A && qtype != KNOT_RRTYPE_AAAA) {
return state;
}
/* Retrieve the IP address that sent the query. */
const struct sockaddr_storage *query_source = knotd_qdata_remote_addr(qdata);
if (query_source == NULL) {
return KNOTD_IN_STATE_ERROR;
}
/* If the socket address family corresponds to the query type (i.e.,
* AF_INET <-> A and AF_INET6 <-> AAAA), put the socket address and
* length into 'rdata' and 'len_rdata'.
*/
const void *rdata = NULL;
uint16_t len_rdata = 0;
if (query_source->ss_family == AF_INET && qtype == KNOT_RRTYPE_A) {
const struct sockaddr_in *sai = (struct sockaddr_in *)query_source;
rdata = &sai->sin_addr.s_addr;
len_rdata = sizeof(sai->sin_addr.s_addr);
} else if (query_source->ss_family == AF_INET6 && qtype == KNOT_RRTYPE_AAAA) {
const struct sockaddr_in6 *sai6 = (struct sockaddr_in6 *)query_source;
rdata = &sai6->sin6_addr;
len_rdata = sizeof(sai6->sin6_addr);
} else {
/* Query type didn't match address family. */
return state;
}
/* Synthesize the response RRset. */
/* TTL is taken from the TTL of the SOA record. */
knot_rrset_t soa = knotd_qdata_zone_apex_rrset(qdata, KNOT_RRTYPE_SOA);
/* Owner name, type, and class are taken from the question. */
knot_rrset_t *rrset = knot_rrset_new(qname, qtype, qclass, soa.ttl, &pkt->mm);
if (rrset == NULL) {
return KNOTD_IN_STATE_ERROR;
}
/* Record data is the query source address. */
int ret = knot_rrset_add_rdata(rrset, rdata, len_rdata, &pkt->mm);
if (ret != KNOT_EOK) {
knot_rrset_free(rrset, &pkt->mm);
return KNOTD_IN_STATE_ERROR;
}
/* Add the new RRset to the response packet. */
ret = knot_pkt_put(pkt, KNOT_COMPR_HINT_QNAME, rrset, KNOT_PF_FREE);
if (ret != KNOT_EOK) {
knot_rrset_free(rrset, &pkt->mm);
return KNOTD_IN_STATE_ERROR;
}
/* Success. */
return KNOTD_IN_STATE_HIT;
}
int whoami_load(knotd_mod_t *mod)
{
/* Hook to the query plan. */
knotd_mod_in_hook(mod, KNOTD_STAGE_ANSWER, whoami_query);
return KNOT_EOK;
}
KNOTD_MOD_API(whoami, KNOTD_MOD_FLAG_SCOPE_ZONE | KNOTD_MOD_FLAG_OPT_CONF,
whoami_load, NULL, NULL, NULL);
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