131 lines
3.9 KiB
C
131 lines
3.9 KiB
C
/*
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* daemon/tcp_conn_limit.h - client TCP connection limit storage for the server.
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*
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* Copyright (c) 2018, NLnet Labs. All rights reserved.
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*
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* This software is open source.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* Neither the name of the NLNET LABS nor the names of its contributors may
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* be used to endorse or promote products derived from this software without
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* specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**
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* \file
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*
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* This file keeps track of the limit on the number of TCP connections
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* each client makes the server.
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*/
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#ifndef DAEMON_TCP_CONN_LIMIT_H
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#define DAEMON_TCP_CONN_LIMIT_H
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#include "util/storage/dnstree.h"
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#include "util/locks.h"
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struct config_file;
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struct regional;
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/**
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* TCP connection limit storage structure
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*/
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struct tcl_list {
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/** regional for allocation */
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struct regional* region;
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/**
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* Tree of the addresses that are TCP connection limited.
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* contents of type tcl_addr.
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*/
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rbtree_type tree;
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};
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/**
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*
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* An address span with connection limit information
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*/
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struct tcl_addr {
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/** node in address tree */
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struct addr_tree_node node;
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/** lock on structure data */
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lock_quick_type lock;
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/** connection limit on this netblock */
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uint32_t limit;
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/** current connection count on this netblock */
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uint32_t count;
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};
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/**
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* Create TCP connection limit structure
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* @return new structure or NULL on error.
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*/
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struct tcl_list* tcl_list_create(void);
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/**
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* Delete TCP connection limit structure.
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* @param tcl: to delete.
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*/
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void tcl_list_delete(struct tcl_list* tcl);
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/**
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* Process TCP connection limit config.
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* @param tcl: where to store.
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* @param cfg: config options.
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* @return 0 on error.
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*/
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int tcl_list_apply_cfg(struct tcl_list* tcl, struct config_file* cfg);
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/**
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* Increment TCP connection count if found, provided the
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* count was below the limit.
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* @param tcl: structure for tcl storage, or NULL.
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* @return: 0 if limit reached, 1 if tcl was NULL or limit not reached.
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*/
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int tcl_new_connection(struct tcl_addr* tcl);
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/**
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* Decrement TCP connection count if found.
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* @param tcl: structure for tcl storage, or NULL.
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*/
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void tcl_close_connection(struct tcl_addr* tcl);
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/**
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* Lookup address to see its TCP connection limit structure
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* @param tcl: structure for address storage.
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* @param addr: address to check
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* @param addrlen: length of addr.
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* @return: tcl structure from this address.
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*/
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struct tcl_addr*
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tcl_addr_lookup(struct tcl_list* tcl, struct sockaddr_storage* addr,
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socklen_t addrlen);
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/**
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* Get memory used by TCP connection limit structure.
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* @param tcl: structure for address storage.
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* @return bytes in use.
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*/
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size_t tcl_list_get_mem(struct tcl_list* tcl);
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#endif /* DAEMON_TCP_CONN_LIMIT_H */
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