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/*
* daemon/tcp_conn_limit.c - client TCP connection limit storage for the server.
*
* 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 helps the server discard excess TCP connections.
*/
#include "config.h"
#include "util/regional.h"
#include "util/log.h"
#include "util/config_file.h"
#include "util/net_help.h"
#include "util/tcp_conn_limit.h"
#include "services/localzone.h"
#include "sldns/str2wire.h"
struct tcl_list*
tcl_list_create(void)
{
struct tcl_list* tcl = (struct tcl_list*)calloc(1,
sizeof(struct tcl_list));
if(!tcl)
return NULL;
tcl->region = regional_create();
if(!tcl->region) {
tcl_list_delete(tcl);
return NULL;
}
return tcl;
}
static void
tcl_list_free_node(rbnode_type* node, void* ATTR_UNUSED(arg))
{
struct tcl_addr* n = (struct tcl_addr*) node;
lock_quick_destroy(&n->lock);
#ifdef THREADS_DISABLED
(void)n;
#endif
}
void
tcl_list_delete(struct tcl_list* tcl)
{
if(!tcl)
return;
traverse_postorder(&tcl->tree, tcl_list_free_node, NULL);
regional_destroy(tcl->region);
free(tcl);
}
/** insert new address into tcl_list structure */
static struct tcl_addr*
tcl_list_insert(struct tcl_list* tcl, struct sockaddr_storage* addr,
socklen_t addrlen, int net, uint32_t limit,
int complain_duplicates)
{
struct tcl_addr* node = regional_alloc_zero(tcl->region,
sizeof(struct tcl_addr));
if(!node)
return NULL;
lock_quick_init(&node->lock);
node->limit = limit;
if(!addr_tree_insert(&tcl->tree, &node->node, addr, addrlen, net)) {
if(complain_duplicates)
verbose(VERB_QUERY, "duplicate tcl address ignored.");
}
return node;
}
/** apply tcl_list string */
static int
tcl_list_str_cfg(struct tcl_list* tcl, const char* str, const char* s2,
int complain_duplicates)
{
struct sockaddr_storage addr;
int net;
socklen_t addrlen;
uint32_t limit;
if(atoi(s2) < 0) {
log_err("bad connection limit %s", s2);
return 0;
}
limit = (uint32_t)atoi(s2);
if(!netblockstrtoaddr(str, UNBOUND_DNS_PORT, &addr, &addrlen, &net)) {
log_err("cannot parse connection limit netblock: %s", str);
return 0;
}
if(!tcl_list_insert(tcl, &addr, addrlen, net, limit,
complain_duplicates)) {
log_err("out of memory");
return 0;
}
return 1;
}
/** read tcl_list config */
static int
read_tcl_list(struct tcl_list* tcl, struct config_file* cfg)
{
struct config_str2list* p;
for(p = cfg->tcp_connection_limits; p; p = p->next) {
log_assert(p->str && p->str2);
if(!tcl_list_str_cfg(tcl, p->str, p->str2, 1))
return 0;
}
return 1;
}
int
tcl_list_apply_cfg(struct tcl_list* tcl, struct config_file* cfg)
{
regional_free_all(tcl->region);
addr_tree_init(&tcl->tree);
if(!read_tcl_list(tcl, cfg))
return 0;
addr_tree_init_parents(&tcl->tree);
return 1;
}
int
tcl_new_connection(struct tcl_addr* tcl)
{
if(tcl) {
int res = 1;
lock_quick_lock(&tcl->lock);
if(tcl->count >= tcl->limit)
res = 0;
else
tcl->count++;
lock_quick_unlock(&tcl->lock);
return res;
}
return 1;
}
void
tcl_close_connection(struct tcl_addr* tcl)
{
if(tcl) {
lock_quick_lock(&tcl->lock);
log_assert(tcl->count > 0);
tcl->count--;
lock_quick_unlock(&tcl->lock);
}
}
struct tcl_addr*
tcl_addr_lookup(struct tcl_list* tcl, struct sockaddr_storage* addr,
socklen_t addrlen)
{
return (struct tcl_addr*)addr_tree_lookup(&tcl->tree,
addr, addrlen);
}
size_t
tcl_list_get_mem(struct tcl_list* tcl)
{
if(!tcl) return 0;
return sizeof(*tcl) + regional_get_mem(tcl->region);
}
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