1 /**
2 * @file
3 * DNS-SD APIs used by LWIP_HOOK_NETCONN_EXTERNAL_RESOLVE
4 *
5 * This implementation assumes the DNS-SD API implementation (most likely provided by
6 * mDNSResponder) is implemented in the same process space as LwIP and can directly
7 * invoke the callback for DNSServiceGetAddrInfo. This is the typical deployment in
8 * an embedded environment where as a traditional OS requires pumping the callback results
9 * through an IPC mechanism (see DNSServiceRefSockFD/DNSServiceProcessResult)
10 *
11 * @defgroup dnssd DNS-SD
12 * @ingroup dns
13 */
14
15 /*
16 * Copyright (c) 2017 Joel Cunningham, Garmin International, Inc. <joel.cunningham@garmin.com>
17 * All rights reserved.
18 *
19 * Redistribution and use in source and binary forms, with or without modification,
20 * are permitted provided that the following conditions are met:
21 *
22 * 1. Redistributions of source code must retain the above copyright notice,
23 * this list of conditions and the following disclaimer.
24 * 2. Redistributions in binary form must reproduce the above copyright notice,
25 * this list of conditions and the following disclaimer in the documentation
26 * and/or other materials provided with the distribution.
27 * 3. The name of the author may not be used to endorse or promote products
28 * derived from this software without specific prior written permission.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
31 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
32 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
33 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
34 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
35 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
36 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
37 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
38 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
39 * OF SUCH DAMAGE.
40 *
41 * This file is part of the lwIP TCP/IP stack.
42 *
43 * Author: Joel Cunningham <joel.cunningham@me.com>
44 *
45 */
46 #include "lwip/opt.h"
47
48 #include "lwip/err.h"
49 #include "lwip/inet.h"
50 #include "lwip/sockets.h"
51 #include "lwip/sys.h"
52
53 #include "dnssd.h"
54
55 /* External headers */
56 #include <string.h>
57 #include <dns_sd.h>
58
59 /* This timeout should allow for multiple queries.
60 mDNSResponder has the following query timeline:
61 Query 1: time = 0s
62 Query 2: time = 1s
63 Query 3: time = 4s
64 */
65 #define GETADDR_TIMEOUT_MS 5000
66 #define LOCAL_DOMAIN ".local"
67
68 /* Only consume .local hosts */
69 #ifndef CONSUME_LOCAL_ONLY
70 #define CONSUME_LOCAL_ONLY 1
71 #endif
72
73 struct addr_clbk_msg {
74 sys_sem_t sem;
75 struct sockaddr_storage addr;
76 err_t err;
77 };
78
79 static void addr_info_callback(DNSServiceRef ref, DNSServiceFlags flags, u32_t interface_index,
80 DNSServiceErrorType error_code, char const* hostname,
81 const struct sockaddr* address, u32_t ttl, void* context);
82
83 int
lwip_dnssd_gethostbyname(const char * name,ip_addr_t * addr,u8_t addrtype,err_t * err)84 lwip_dnssd_gethostbyname(const char *name, ip_addr_t *addr, u8_t addrtype, err_t *err)
85 {
86 DNSServiceErrorType result;
87 DNSServiceRef ref;
88 struct addr_clbk_msg msg;
89 char *p;
90
91 /* @todo: use with IPv6 */
92 LWIP_UNUSED_ARG(addrtype);
93
94 #if CONSUME_LOCAL_ONLY
95 /* check if this is a .local host. If it is, then we consume the query */
96 p = strstr(name, LOCAL_DOMAIN);
97 if (p == NULL) {
98 return 0; /* not consumed */
99 }
100 p += (sizeof(LOCAL_DOMAIN) - 1);
101 /* check to make sure .local isn't a substring (only allow .local\0 or .local.\0) */
102 if ((*p != '.' && *p != '\0') ||
103 (*p == '.' && *(p + 1) != '\0')) {
104 return 0; /* not consumed */
105 }
106 #endif /* CONSUME_LOCAL_ONLY */
107
108 msg.err = sys_sem_new(&msg.sem, 0);
109 if (msg.err != ERR_OK) {
110 goto query_done;
111 }
112
113 msg.err = ERR_TIMEOUT;
114 result = DNSServiceGetAddrInfo(&ref, 0, 0, kDNSServiceProtocol_IPv4, name, addr_info_callback, &msg);
115 if (result == kDNSServiceErr_NoError) {
116 sys_arch_sem_wait(&msg.sem, GETADDR_TIMEOUT_MS);
117 DNSServiceRefDeallocate(ref);
118
119 /* We got a response */
120 if (msg.err == ERR_OK) {
121 struct sockaddr_in* addr_in = (struct sockaddr_in *)&msg.addr;
122 if (addr_in->sin_family == AF_INET) {
123 inet_addr_to_ip4addr(ip_2_ip4(addr), &addr_in->sin_addr);
124 } else {
125 /* @todo add IPv6 support */
126 msg.err = ERR_VAL;
127 }
128 }
129 }
130 sys_sem_free(&msg.sem);
131
132 /* Query has been consumed and is finished */
133 query_done:
134 *err = msg.err;
135 return 1;
136 }
137
138 static void
addr_info_callback(DNSServiceRef ref,DNSServiceFlags flags,u32_t interface_index,DNSServiceErrorType error_code,char const * hostname,const struct sockaddr * address,u32_t ttl,void * context)139 addr_info_callback(DNSServiceRef ref, DNSServiceFlags flags, u32_t interface_index,
140 DNSServiceErrorType error_code, char const* hostname,
141 const struct sockaddr* address, u32_t ttl, void* context)
142 {
143 struct addr_clbk_msg* msg = (struct addr_clbk_msg*)context;
144 struct sockaddr_in* addr_in = (struct sockaddr_in *)address;
145
146 LWIP_UNUSED_ARG(ref);
147 LWIP_UNUSED_ARG(flags);
148 LWIP_UNUSED_ARG(interface_index);
149 LWIP_UNUSED_ARG(hostname);
150 LWIP_UNUSED_ARG(ttl);
151 LWIP_UNUSED_ARG(context);
152
153 if ((error_code == kDNSServiceErr_NoError) &&
154 (addr_in->sin_family == AF_INET)) {
155 MEMCPY(&msg->addr, addr_in, sizeof(*addr_in));
156 msg->err = ERR_OK;
157 }
158 else {
159 /* @todo add IPv6 support */
160 msg->err = ERR_VAL;
161 }
162
163 sys_sem_signal(&msg->sem);
164 } /* addr_info_callback() */
165