1 /* 2 * util/edns.c - handle base EDNS options. 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 contains functions for base EDNS options. 40 */ 41 42 #include "config.h" 43 #include "util/edns.h" 44 #include "util/config_file.h" 45 #include "util/netevent.h" 46 #include "util/net_help.h" 47 #include "util/regional.h" 48 #include "util/data/msgparse.h" 49 #include "util/data/msgreply.h" 50 51 #if 0 52 /* XXX: remove me */ 53 #include "edns.h" 54 #endif 55 56 struct edns_strings* edns_strings_create(void) 57 { 58 struct edns_strings* edns_strings = calloc(1, 59 sizeof(struct edns_strings)); 60 if(!edns_strings) 61 return NULL; 62 if(!(edns_strings->region = regional_create())) { 63 edns_strings_delete(edns_strings); 64 return NULL; 65 } 66 return edns_strings; 67 } 68 69 void edns_strings_delete(struct edns_strings* edns_strings) 70 { 71 if(!edns_strings) 72 return; 73 regional_destroy(edns_strings->region); 74 free(edns_strings); 75 } 76 77 static int 78 edns_strings_client_insert(struct edns_strings* edns_strings, 79 struct sockaddr_storage* addr, socklen_t addrlen, int net, 80 const char* string) 81 { 82 struct edns_string_addr* esa = regional_alloc_zero(edns_strings->region, 83 sizeof(struct edns_string_addr)); 84 if(!esa) 85 return 0; 86 esa->string_len = strlen(string); 87 esa->string = regional_alloc_init(edns_strings->region, string, 88 esa->string_len); 89 if(!esa->string) 90 return 0; 91 if(!addr_tree_insert(&edns_strings->client_strings, &esa->node, addr, 92 addrlen, net)) { 93 verbose(VERB_QUERY, "duplicate EDNS client string ignored."); 94 } 95 return 1; 96 } 97 98 int edns_strings_apply_cfg(struct edns_strings* edns_strings, 99 struct config_file* config) 100 { 101 struct config_str2list* c; 102 regional_free_all(edns_strings->region); 103 addr_tree_init(&edns_strings->client_strings); 104 105 for(c=config->edns_client_strings; c; c=c->next) { 106 struct sockaddr_storage addr; 107 socklen_t addrlen; 108 int net; 109 log_assert(c->str && c->str2); 110 111 if(!netblockstrtoaddr(c->str, UNBOUND_DNS_PORT, &addr, &addrlen, 112 &net)) { 113 log_err("cannot parse EDNS client string IP netblock: " 114 "%s", c->str); 115 return 0; 116 } 117 if(!edns_strings_client_insert(edns_strings, &addr, addrlen, 118 net, c->str2)) { 119 log_err("out of memory while adding EDNS strings"); 120 return 0; 121 } 122 } 123 edns_strings->client_string_opcode = config->edns_client_string_opcode; 124 125 addr_tree_init_parents(&edns_strings->client_strings); 126 return 1; 127 } 128 129 struct edns_string_addr* 130 edns_string_addr_lookup(rbtree_type* tree, struct sockaddr_storage* addr, 131 socklen_t addrlen) 132 { 133 return (struct edns_string_addr*)addr_tree_lookup(tree, addr, addrlen); 134 } 135 136 static int edns_keepalive(struct edns_data* edns_out, struct edns_data* edns_in, 137 struct comm_point* c, struct regional* region) 138 { 139 if(c->type == comm_udp) 140 return 1; 141 142 /* To respond with a Keepalive option, the client connection 143 * must have received one message with a TCP Keepalive EDNS option, 144 * and that option must have 0 length data. Subsequent messages 145 * sent on that connection will have a TCP Keepalive option. 146 */ 147 if(c->tcp_keepalive || 148 edns_opt_list_find(edns_in->opt_list, LDNS_EDNS_KEEPALIVE)) { 149 int keepalive = c->tcp_timeout_msec / 100; 150 uint8_t data[2]; 151 data[0] = (uint8_t)((keepalive >> 8) & 0xff); 152 data[1] = (uint8_t)(keepalive & 0xff); 153 if(!edns_opt_list_append(&edns_out->opt_list, LDNS_EDNS_KEEPALIVE, 154 sizeof(data), data, region)) 155 return 0; 156 c->tcp_keepalive = 1; 157 } 158 return 1; 159 } 160 161 int apply_edns_options(struct edns_data* edns_out, struct edns_data* edns_in, 162 struct config_file* cfg, struct comm_point* c, struct regional* region) 163 { 164 if(cfg->do_tcp_keepalive && 165 !edns_keepalive(edns_out, edns_in, c, region)) 166 return 0; 167 168 if (cfg->nsid && edns_opt_list_find(edns_in->opt_list, LDNS_EDNS_NSID) 169 && !edns_opt_list_append(&edns_out->opt_list, 170 LDNS_EDNS_NSID, cfg->nsid_len, cfg->nsid, region)) 171 return 0; 172 173 if(!cfg->pad_responses || c->type != comm_tcp || !c->ssl 174 || !edns_opt_list_find(edns_in->opt_list, LDNS_EDNS_PADDING)) { 175 ; /* pass */ 176 } 177 178 else if(!edns_opt_list_append(&edns_out->opt_list, LDNS_EDNS_PADDING 179 , 0, NULL, region)) 180 return 0; 181 else 182 edns_out->padding_block_size = cfg->pad_responses_block_size; 183 184 return 1; 185 } 186