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/*
* util/edns.c - handle base EDNS options.
*
* Copyright (c) 2018, 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 functions for base EDNS options.
*/
#include "config.h"
#include "util/edns.h"
#include "util/config_file.h"
#include "util/netevent.h"
#include "util/regional.h"
#include "util/data/msgparse.h"
#include "util/data/msgreply.h"
static int edns_keepalive(struct edns_data* edns_out, struct edns_data* edns_in,
struct comm_point* c, struct regional* region)
{
if(c->type == comm_udp)
return 1;
/* To respond with a Keepalive option, the client connection
* must have received one message with a TCP Keepalive EDNS option,
* and that option must have 0 length data. Subsequent messages
* sent on that connection will have a TCP Keepalive option.
*/
if(c->tcp_keepalive ||
edns_opt_list_find(edns_in->opt_list, LDNS_EDNS_KEEPALIVE)) {
int keepalive = c->tcp_timeout_msec / 100;
uint8_t data[2];
data[0] = (uint8_t)((keepalive >> 8) & 0xff);
data[1] = (uint8_t)(keepalive & 0xff);
if(!edns_opt_list_append(&edns_out->opt_list, LDNS_EDNS_KEEPALIVE,
sizeof(data), data, region))
return 0;
c->tcp_keepalive = 1;
}
return 1;
}
int apply_edns_options(struct edns_data* edns_out, struct edns_data* edns_in,
struct config_file* cfg, struct comm_point* c, struct regional* region)
{
if(cfg->do_tcp_keepalive &&
!edns_keepalive(edns_out, edns_in, c, region))
return 0;
return 1;
}
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