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/*
* Copyright (c) 2019-2020, CZ.NIC, z.s.p.o.
* All rights reserved.
*
* This file is part of dnsjit.
*
* dnsjit 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.
*
* dnsjit 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 dnsjit. If not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "output/dnssim.h"
#include "output/dnssim/internal.h"
#include "output/dnssim/ll.h"
#include "core/assert.h"
static core_log_t _log = LOG_T_INIT("output.dnssim");
static int _process_udp_response(uv_udp_t* handle, ssize_t nread, const uv_buf_t* buf)
{
_output_dnssim_query_udp_t* qry = (_output_dnssim_query_udp_t*)handle->data;
_output_dnssim_request_t* req;
core_object_payload_t payload = CORE_OBJECT_PAYLOAD_INIT(NULL);
core_object_dns_t dns_a = CORE_OBJECT_DNS_INIT(&payload);
mlassert(qry, "qry is nil");
mlassert(qry->qry.req, "query must be part of a request");
req = qry->qry.req;
payload.payload = (uint8_t*)buf->base;
payload.len = nread;
dns_a.obj_prev = (core_object_t*)&payload;
int ret = core_object_dns_parse_header(&dns_a);
if (ret != 0) {
mldebug("udp response malformed");
return _ERR_MALFORMED;
}
if (dns_a.id != req->dns_q->id) {
mldebug("udp response msgid mismatch %x(q) != %x(a)", req->dns_q->id, dns_a.id);
return _ERR_MSGID;
}
if (dns_a.tc == 1) {
mldebug("udp response has TC=1");
return _ERR_TC;
}
ret = _output_dnssim_answers_request(req, &dns_a);
if (ret != 0) {
mlwarning("udp reponse question mismatch");
return _ERR_QUESTION;
}
_output_dnssim_request_answered(req, &dns_a);
return 0;
}
static void _on_udp_query_recv(uv_udp_t* handle, ssize_t nread, const uv_buf_t* buf, const struct sockaddr* addr, unsigned flags)
{
if (nread > 0) {
mldebug("udp recv: %d", nread);
// TODO handle TC=1
_process_udp_response(handle, nread, buf);
}
if (buf->base != NULL) {
free(buf->base);
}
}
static void _on_query_udp_closed(uv_handle_t* handle)
{
_output_dnssim_query_udp_t* qry = (_output_dnssim_query_udp_t*)handle->data;
_output_dnssim_request_t* req;
mlassert(qry, "qry is nil");
mlassert(qry->qry.req, "query must be part of a request");
req = qry->qry.req;
free(qry->handle);
_ll_remove(req->qry, &qry->qry);
free(qry);
if (req->qry == NULL)
_output_dnssim_maybe_free_request(req);
}
void _output_dnssim_close_query_udp(_output_dnssim_query_udp_t* qry)
{
int ret;
mlassert(qry, "qry is nil");
ret = uv_udp_recv_stop(qry->handle);
if (ret < 0) {
mldebug("failed uv_udp_recv_stop(): %s", uv_strerror(ret));
}
uv_close((uv_handle_t*)qry->handle, _on_query_udp_closed);
}
int _output_dnssim_create_query_udp(output_dnssim_t* self, _output_dnssim_request_t* req)
{
int ret;
_output_dnssim_query_udp_t* qry;
core_object_payload_t* payload;
mlassert_self();
lassert(req, "req is nil");
payload = (core_object_payload_t*)req->dns_q->obj_prev;
lfatal_oom(qry = calloc(1, sizeof(_output_dnssim_query_udp_t)));
lfatal_oom(qry->handle = malloc(sizeof(uv_udp_t)));
qry->qry.transport = OUTPUT_DNSSIM_TRANSPORT_UDP;
qry->qry.req = req;
qry->buf = uv_buf_init((char*)payload->payload, payload->len);
qry->handle->data = (void*)qry;
ret = uv_udp_init(&_self->loop, qry->handle);
if (ret < 0) {
lwarning("failed to init uv_udp_t");
goto failure;
}
_ll_append(req->qry, &qry->qry);
ret = _output_dnssim_bind_before_connect(self, (uv_handle_t*)qry->handle);
if (ret < 0)
return ret;
ret = uv_udp_try_send(qry->handle, &qry->buf, 1, (struct sockaddr*)&_self->target);
if (ret < 0) {
lwarning("failed to send udp packet: %s", uv_strerror(ret));
return ret;
}
// listen for reply
ret = uv_udp_recv_start(qry->handle, _output_dnssim_on_uv_alloc, _on_udp_query_recv);
if (ret < 0) {
lwarning("failed uv_udp_recv_start(): %s", uv_strerror(ret));
return ret;
}
return 0;
failure:
free(qry->handle);
free(qry);
return ret;
}
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