1 /* 2 * daemon/tcp_conn_limit.h - client TCP connection limit storage for the server. 3 * 4 * Copyright (c) 2018, NLnet Labs. All rights reserved. 5 * 6 * This software is open source. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * Redistributions of source code must retain the above copyright notice, 13 * this list of conditions and the following disclaimer. 14 * 15 * Redistributions in binary form must reproduce the above copyright notice, 16 * this list of conditions and the following disclaimer in the documentation 17 * and/or other materials provided with the distribution. 18 * 19 * Neither the name of the NLNET LABS nor the names of its contributors may 20 * be used to endorse or promote products derived from this software without 21 * specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 27 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 28 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED 29 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 30 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 31 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 32 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 33 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 */ 35 36 /** 37 * \file 38 * 39 * This file keeps track of the limit on the number of TCP connections 40 * each client makes the server. 41 */ 42 43 #ifndef DAEMON_TCP_CONN_LIMIT_H 44 #define DAEMON_TCP_CONN_LIMIT_H 45 #include "util/storage/dnstree.h" 46 #include "util/locks.h" 47 struct config_file; 48 struct regional; 49 50 /** 51 * TCP connection limit storage structure 52 */ 53 struct tcl_list { 54 /** regional for allocation */ 55 struct regional* region; 56 /** 57 * Tree of the addresses that are TCP connection limited. 58 * contents of type tcl_addr. 59 */ 60 rbtree_type tree; 61 }; 62 63 /** 64 * 65 * An address span with connection limit information 66 */ 67 struct tcl_addr { 68 /** node in address tree */ 69 struct addr_tree_node node; 70 /** lock on structure data */ 71 lock_quick_type lock; 72 /** connection limit on this netblock */ 73 uint32_t limit; 74 /** current connection count on this netblock */ 75 uint32_t count; 76 }; 77 78 /** 79 * Create TCP connection limit structure 80 * @return new structure or NULL on error. 81 */ 82 struct tcl_list* tcl_list_create(void); 83 84 /** 85 * Delete TCP connection limit structure. 86 * @param tcl: to delete. 87 */ 88 void tcl_list_delete(struct tcl_list* tcl); 89 90 /** 91 * Process TCP connection limit config. 92 * @param tcl: where to store. 93 * @param cfg: config options. 94 * @return 0 on error. 95 */ 96 int tcl_list_apply_cfg(struct tcl_list* tcl, struct config_file* cfg); 97 98 /** 99 * Increment TCP connection count if found, provided the 100 * count was below the limit. 101 * @param tcl: structure for tcl storage, or NULL. 102 * @return: 0 if limit reached, 1 if tcl was NULL or limit not reached. 103 */ 104 int tcl_new_connection(struct tcl_addr* tcl); 105 106 /** 107 * Decrement TCP connection count if found. 108 * @param tcl: structure for tcl storage, or NULL. 109 */ 110 void tcl_close_connection(struct tcl_addr* tcl); 111 112 /** 113 * Lookup address to see its TCP connection limit structure 114 * @param tcl: structure for address storage. 115 * @param addr: address to check 116 * @param addrlen: length of addr. 117 * @return: tcl structure from this address. 118 */ 119 struct tcl_addr* 120 tcl_addr_lookup(struct tcl_list* tcl, struct sockaddr_storage* addr, 121 socklen_t addrlen); 122 123 /** 124 * Get memory used by TCP connection limit structure. 125 * @param tcl: structure for address storage. 126 * @return bytes in use. 127 */ 128 size_t tcl_list_get_mem(struct tcl_list* tcl); 129 130 #endif /* DAEMON_TCP_CONN_LIMIT_H */ 131