edns.c revision 368693 
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
56struct 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
69void 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
77static int
78edns_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
98int 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
129struct edns_string_addr*
130edns_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
136static 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
161int 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	return 1;
169}
170