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/*
* Author Jerry Lundström <jerry@dns-oarc.net>
* Copyright (c) 2019-2023, OARC, Inc.
* All rights reserved.
*
* This file is part of the dnswire library.
*
* dnswire library is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* dnswire library 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with dnswire library. If not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include "dnswire/decoder.h"
#include "dnswire/trace.h"
#include <assert.h>
const char* const dnswire_decoder_state_string[] = {
"reading_control",
"checking_ready",
"checking_accept",
"reading_start",
"checking_start",
"reading_frames",
"checking_finish",
"done",
};
#define __state(h, s) \
__trace("state %s => %s", dnswire_decoder_state_string[(h)->state], dnswire_decoder_state_string[s]); \
(h)->state = s;
enum dnswire_result dnswire_decoder_decode(struct dnswire_decoder* handle, const uint8_t* data, size_t len)
{
assert(handle);
assert(data);
assert(len);
switch (handle->state) {
case dnswire_decoder_reading_control:
switch (tinyframe_read(&handle->reader, data, len)) {
case tinyframe_have_control:
switch (handle->reader.control.type) {
case TINYFRAME_CONTROL_READY:
// indicate that we have bidirectional communications
__state(handle, dnswire_decoder_checking_ready);
return dnswire_again;
case TINYFRAME_CONTROL_ACCEPT:
// indicate that we have bidirectional communications
__state(handle, dnswire_decoder_checking_accept);
return dnswire_again;
case TINYFRAME_CONTROL_START:
__state(handle, dnswire_decoder_checking_start);
return dnswire_again;
default:
break;
}
break;
case tinyframe_need_more:
return dnswire_need_more;
default:
break;
}
return dnswire_error;
case dnswire_decoder_checking_ready:
switch (tinyframe_read(&handle->reader, data, len)) {
case tinyframe_have_control_field:
if (handle->reader.control_field.type != TINYFRAME_CONTROL_FIELD_CONTENT_TYPE) {
return dnswire_error;
}
if (!strncmp(DNSTAP_PROTOBUF_CONTENT_TYPE, (const char*)handle->reader.control_field.data, handle->reader.control_field.length)) {
handle->ready_support_dnstap_protobuf = 1;
}
if (!handle->reader.control_length_left) {
__state(handle, dnswire_decoder_reading_start);
return dnswire_bidirectional;
}
return dnswire_again;
case tinyframe_need_more:
return dnswire_need_more;
default:
return dnswire_error;
}
case dnswire_decoder_checking_accept:
switch (tinyframe_read(&handle->reader, data, len)) {
case tinyframe_have_control_field:
if (handle->reader.control_field.type != TINYFRAME_CONTROL_FIELD_CONTENT_TYPE) {
return dnswire_error;
}
if (!strncmp(DNSTAP_PROTOBUF_CONTENT_TYPE, (const char*)handle->reader.control_field.data, handle->reader.control_field.length)) {
handle->accept_support_dnstap_protobuf = 1;
}
if (!handle->reader.control_length_left) {
__state(handle, dnswire_decoder_checking_finish);
return dnswire_bidirectional;
}
return dnswire_again;
case tinyframe_need_more:
return dnswire_need_more;
default:
return dnswire_error;
}
case dnswire_decoder_reading_start:
switch (tinyframe_read(&handle->reader, data, len)) {
case tinyframe_have_control:
switch (handle->reader.control.type) {
case TINYFRAME_CONTROL_START:
__state(handle, dnswire_decoder_checking_start);
return dnswire_again;
default:
break;
}
return dnswire_error;
case tinyframe_need_more:
return dnswire_need_more;
default:
return dnswire_error;
}
case dnswire_decoder_checking_start:
switch (tinyframe_read(&handle->reader, data, len)) {
case tinyframe_have_control_field:
if (handle->reader.control_field.type != TINYFRAME_CONTROL_FIELD_CONTENT_TYPE) {
return dnswire_error;
}
if (strncmp(DNSTAP_PROTOBUF_CONTENT_TYPE, (const char*)handle->reader.control_field.data, handle->reader.control_field.length)) {
return dnswire_error;
}
__state(handle, dnswire_decoder_reading_frames);
return dnswire_again;
case tinyframe_need_more:
return dnswire_need_more;
default:
return dnswire_error;
}
case dnswire_decoder_reading_frames:
switch (tinyframe_read(&handle->reader, data, len)) {
case tinyframe_have_frame:
dnstap_cleanup(&handle->dnstap);
if (dnstap_decode_protobuf(&handle->dnstap, handle->reader.frame.data, handle->reader.frame.length)) {
return dnswire_error;
}
return dnswire_have_dnstap;
case tinyframe_need_more:
return dnswire_need_more;
case tinyframe_stopped:
__state(handle, dnswire_decoder_done);
return dnswire_endofdata;
default:
return dnswire_error;
}
case dnswire_decoder_checking_finish:
switch (tinyframe_read(&handle->reader, data, len)) {
case tinyframe_finished:
__state(handle, dnswire_decoder_done);
return dnswire_endofdata;
case tinyframe_need_more:
return dnswire_need_more;
default:
return dnswire_error;
}
case dnswire_decoder_done:
break;
}
return dnswire_error;
}
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