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_tags* edns_tags_create(void) 57 { 58 struct edns_tags* edns_tags = calloc(1, sizeof(struct edns_tags)); 59 if(!edns_tags) 60 return NULL; 61 if(!(edns_tags->region = regional_create())) { 62 edns_tags_delete(edns_tags); 63 return NULL; 64 } 65 return edns_tags; 66 } 67 68 void edns_tags_delete(struct edns_tags* edns_tags) 69 { 70 if(!edns_tags) 71 return; 72 regional_destroy(edns_tags->region); 73 free(edns_tags); 74 } 75 76 static int 77 edns_tags_client_insert(struct edns_tags* edns_tags, 78 struct sockaddr_storage* addr, socklen_t addrlen, int net, 79 uint16_t tag_data) 80 { 81 struct edns_tag_addr* eta = regional_alloc_zero(edns_tags->region, 82 sizeof(struct edns_tag_addr)); 83 if(!eta) 84 return 0; 85 eta->tag_data = tag_data; 86 if(!addr_tree_insert(&edns_tags->client_tags, &eta->node, addr, addrlen, 87 net)) { 88 verbose(VERB_QUERY, "duplicate EDNS client tag ignored."); 89 } 90 return 1; 91 } 92 93 int edns_tags_apply_cfg(struct edns_tags* edns_tags, 94 struct config_file* config) 95 { 96 struct config_str2list* c; 97 regional_free_all(edns_tags->region); 98 addr_tree_init(&edns_tags->client_tags); 99 100 for(c=config->edns_client_tags; c; c=c->next) { 101 struct sockaddr_storage addr; 102 socklen_t addrlen; 103 int net; 104 uint16_t tag_data; 105 log_assert(c->str && c->str2); 106 107 if(!netblockstrtoaddr(c->str, UNBOUND_DNS_PORT, &addr, &addrlen, 108 &net)) { 109 log_err("cannot parse EDNS client tag IP netblock: %s", 110 c->str); 111 return 0; 112 } 113 tag_data = atoi(c->str2); /* validated in config parser */ 114 if(!edns_tags_client_insert(edns_tags, &addr, addrlen, net, 115 tag_data)) { 116 log_err("out of memory while adding EDNS tags"); 117 return 0; 118 } 119 } 120 edns_tags->client_tag_opcode = config->edns_client_tag_opcode; 121 122 addr_tree_init_parents(&edns_tags->client_tags); 123 return 1; 124 } 125 126 struct edns_tag_addr* 127 edns_tag_addr_lookup(rbtree_type* tree, struct sockaddr_storage* addr, 128 socklen_t addrlen) 129 { 130 return (struct edns_tag_addr*)addr_tree_lookup(tree, addr, addrlen); 131 } 132 133 static int edns_keepalive(struct edns_data* edns_out, struct edns_data* edns_in, 134 struct comm_point* c, struct regional* region) 135 { 136 if(c->type == comm_udp) 137 return 1; 138 139 /* To respond with a Keepalive option, the client connection 140 * must have received one message with a TCP Keepalive EDNS option, 141 * and that option must have 0 length data. Subsequent messages 142 * sent on that connection will have a TCP Keepalive option. 143 */ 144 if(c->tcp_keepalive || 145 edns_opt_list_find(edns_in->opt_list, LDNS_EDNS_KEEPALIVE)) { 146 int keepalive = c->tcp_timeout_msec / 100; 147 uint8_t data[2]; 148 data[0] = (uint8_t)((keepalive >> 8) & 0xff); 149 data[1] = (uint8_t)(keepalive & 0xff); 150 if(!edns_opt_list_append(&edns_out->opt_list, LDNS_EDNS_KEEPALIVE, 151 sizeof(data), data, region)) 152 return 0; 153 c->tcp_keepalive = 1; 154 } 155 return 1; 156 } 157 158 int apply_edns_options(struct edns_data* edns_out, struct edns_data* edns_in, 159 struct config_file* cfg, struct comm_point* c, struct regional* region) 160 { 161 if(cfg->do_tcp_keepalive && 162 !edns_keepalive(edns_out, edns_in, c, region)) 163 return 0; 164 165 return 1; 166 } 167