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Diffstat (limited to 'util/tcp_conn_limit.h')
| -rw-r--r-- | util/tcp_conn_limit.h | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/util/tcp_conn_limit.h b/util/tcp_conn_limit.h new file mode 100644 index 000000000000..4fb71a328036 --- /dev/null +++ b/util/tcp_conn_limit.h @@ -0,0 +1,130 @@ +/* + * 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 */ |