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/*
* daemon/tcp_conn_limit.h - 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 keeps track of the limit on the number of TCP connections
* each client makes the server.
*/
#ifndef DAEMON_TCP_CONN_LIMIT_H
#define DAEMON_TCP_CONN_LIMIT_H
#include "util/storage/dnstree.h"
#include "util/locks.h"
struct config_file;
struct regional;
/**
* TCP connection limit storage structure
*/
struct tcl_list {
/** regional for allocation */
struct regional* region;
/**
* Tree of the addresses that are TCP connection limited.
* contents of type tcl_addr.
*/
rbtree_type tree;
};
/**
*
* An address span with connection limit information
*/
struct tcl_addr {
/** node in address tree */
struct addr_tree_node node;
/** lock on structure data */
lock_quick_type lock;
/** connection limit on this netblock */
uint32_t limit;
/** current connection count on this netblock */
uint32_t count;
};
/**
* Create TCP connection limit structure
* @return new structure or NULL on error.
*/
struct tcl_list* tcl_list_create(void);
/**
* Delete TCP connection limit structure.
* @param tcl: to delete.
*/
void tcl_list_delete(struct tcl_list* tcl);
/**
* Process TCP connection limit config.
* @param tcl: where to store.
* @param cfg: config options.
* @return 0 on error.
*/
int tcl_list_apply_cfg(struct tcl_list* tcl, struct config_file* cfg);
/**
* Increment TCP connection count if found, provided the
* count was below the limit.
* @param tcl: structure for tcl storage, or NULL.
* @return: 0 if limit reached, 1 if tcl was NULL or limit not reached.
*/
int tcl_new_connection(struct tcl_addr* tcl);
/**
* Decrement TCP connection count if found.
* @param tcl: structure for tcl storage, or NULL.
*/
void tcl_close_connection(struct tcl_addr* tcl);
/**
* Lookup address to see its TCP connection limit structure
* @param tcl: structure for address storage.
* @param addr: address to check
* @param addrlen: length of addr.
* @return: tcl structure from this address.
*/
struct tcl_addr*
tcl_addr_lookup(struct tcl_list* tcl, struct sockaddr_storage* addr,
socklen_t addrlen);
/**
* Get memory used by TCP connection limit structure.
* @param tcl: structure for address storage.
* @return bytes in use.
*/
size_t tcl_list_get_mem(struct tcl_list* tcl);
#endif /* DAEMON_TCP_CONN_LIMIT_H */
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