1 /*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #define TRACE_TAG TRANSPORT
18
19 #include "transport.h"
20
21 #ifdef _WIN32
22 #include <winsock2.h>
23 #else
24 #include <arpa/inet.h>
25 #endif
26
27 #include <thread>
28
29 #include <android-base/stringprintf.h>
30 #include <dns_sd.h>
31
32 #include "adb_mdns.h"
33 #include "adb_trace.h"
34 #include "fdevent.h"
35 #include "sysdeps.h"
36
37 static DNSServiceRef service_ref;
38 static fdevent service_ref_fde;
39
40 // Use adb_DNSServiceRefSockFD() instead of calling DNSServiceRefSockFD()
41 // directly so that the socket is put through the appropriate compatibility
42 // layers to work with the rest of ADB's internal APIs.
adb_DNSServiceRefSockFD(DNSServiceRef ref)43 static inline int adb_DNSServiceRefSockFD(DNSServiceRef ref) {
44 return adb_register_socket(DNSServiceRefSockFD(ref));
45 }
46 #define DNSServiceRefSockFD ___xxx_DNSServiceRefSockFD
47
48 static void DNSSD_API register_service_ip(DNSServiceRef sdRef,
49 DNSServiceFlags flags,
50 uint32_t interfaceIndex,
51 DNSServiceErrorType errorCode,
52 const char* hostname,
53 const sockaddr* address,
54 uint32_t ttl,
55 void* context);
56
pump_service_ref(int,unsigned ev,void * data)57 static void pump_service_ref(int /*fd*/, unsigned ev, void* data) {
58 DNSServiceRef* ref = reinterpret_cast<DNSServiceRef*>(data);
59
60 if (ev & FDE_READ)
61 DNSServiceProcessResult(*ref);
62 }
63
64 class AsyncServiceRef {
65 public:
Initialized()66 bool Initialized() {
67 return initialized_;
68 }
69
~AsyncServiceRef()70 virtual ~AsyncServiceRef() {
71 if (! initialized_) {
72 return;
73 }
74
75 DNSServiceRefDeallocate(sdRef_);
76 fdevent_remove(&fde_);
77 }
78
79 protected:
80 DNSServiceRef sdRef_;
81
Initialize()82 void Initialize() {
83 fdevent_install(&fde_, adb_DNSServiceRefSockFD(sdRef_),
84 pump_service_ref, &sdRef_);
85 fdevent_set(&fde_, FDE_READ);
86 initialized_ = true;
87 }
88
89 private:
90 bool initialized_;
91 fdevent fde_;
92 };
93
94 class ResolvedService : public AsyncServiceRef {
95 public:
96 virtual ~ResolvedService() = default;
97
ResolvedService(std::string name,uint32_t interfaceIndex,const char * hosttarget,uint16_t port)98 ResolvedService(std::string name, uint32_t interfaceIndex,
99 const char* hosttarget, uint16_t port) :
100 name_(name),
101 port_(port) {
102
103 /* TODO: We should be able to get IPv6 support by adding
104 * kDNSServiceProtocol_IPv6 to the flags below. However, when we do
105 * this, we get served link-local addresses that are usually useless to
106 * connect to. What's more, we seem to /only/ get those and nothing else.
107 * If we want IPv6 in the future we'll have to figure out why.
108 */
109 DNSServiceErrorType ret =
110 DNSServiceGetAddrInfo(
111 &sdRef_, 0, interfaceIndex,
112 kDNSServiceProtocol_IPv4, hosttarget,
113 register_service_ip, reinterpret_cast<void*>(this));
114
115 if (ret != kDNSServiceErr_NoError) {
116 D("Got %d from DNSServiceGetAddrInfo.", ret);
117 } else {
118 Initialize();
119 }
120 }
121
Connect(const sockaddr * address)122 void Connect(const sockaddr* address) {
123 char ip_addr[INET6_ADDRSTRLEN];
124 const void* ip_addr_data;
125 const char* addr_format;
126
127 if (address->sa_family == AF_INET) {
128 ip_addr_data =
129 &reinterpret_cast<const sockaddr_in*>(address)->sin_addr;
130 addr_format = "%s:%hu";
131 } else if (address->sa_family == AF_INET6) {
132 ip_addr_data =
133 &reinterpret_cast<const sockaddr_in6*>(address)->sin6_addr;
134 addr_format = "[%s]:%hu";
135 } else { // Should be impossible
136 D("mDNS resolved non-IP address.");
137 return;
138 }
139
140 // Winsock version requires the const cast Because Microsoft.
141 if (!inet_ntop(address->sa_family, const_cast<void*>(ip_addr_data),
142 ip_addr, INET6_ADDRSTRLEN)) {
143 D("Could not convert IP address to string.");
144 return;
145 }
146
147 std::string response;
148 connect_device(android::base::StringPrintf(addr_format, ip_addr, port_),
149 &response);
150 D("Connect to %s (%s:%hu) : %s", name_.c_str(), ip_addr, port_,
151 response.c_str());
152 }
153
154 private:
155 std::string name_;
156 const uint16_t port_;
157 };
158
register_service_ip(DNSServiceRef,DNSServiceFlags,uint32_t,DNSServiceErrorType,const char *,const sockaddr * address,uint32_t,void * context)159 static void DNSSD_API register_service_ip(DNSServiceRef /*sdRef*/,
160 DNSServiceFlags /*flags*/,
161 uint32_t /*interfaceIndex*/,
162 DNSServiceErrorType /*errorCode*/,
163 const char* /*hostname*/,
164 const sockaddr* address,
165 uint32_t /*ttl*/,
166 void* context) {
167 D("Got IP for service.");
168 std::unique_ptr<ResolvedService> data(
169 reinterpret_cast<ResolvedService*>(context));
170 data->Connect(address);
171 }
172
173 static void DNSSD_API register_resolved_mdns_service(DNSServiceRef sdRef,
174 DNSServiceFlags flags,
175 uint32_t interfaceIndex,
176 DNSServiceErrorType errorCode,
177 const char* fullname,
178 const char* hosttarget,
179 uint16_t port,
180 uint16_t txtLen,
181 const unsigned char* txtRecord,
182 void* context);
183
184 class DiscoveredService : public AsyncServiceRef {
185 public:
DiscoveredService(uint32_t interfaceIndex,const char * serviceName,const char * regtype,const char * domain)186 DiscoveredService(uint32_t interfaceIndex, const char* serviceName,
187 const char* regtype, const char* domain)
188 : serviceName_(serviceName) {
189
190 DNSServiceErrorType ret =
191 DNSServiceResolve(&sdRef_, 0, interfaceIndex, serviceName, regtype,
192 domain, register_resolved_mdns_service,
193 reinterpret_cast<void*>(this));
194
195 if (ret != kDNSServiceErr_NoError) {
196 D("Got %d from DNSServiceResolve.", ret);
197 } else {
198 Initialize();
199 }
200 }
201
ServiceName()202 const char* ServiceName() {
203 return serviceName_.c_str();
204 }
205
206 private:
207 std::string serviceName_;
208 };
209
register_resolved_mdns_service(DNSServiceRef sdRef,DNSServiceFlags flags,uint32_t interfaceIndex,DNSServiceErrorType errorCode,const char * fullname,const char * hosttarget,uint16_t port,uint16_t,const unsigned char *,void * context)210 static void DNSSD_API register_resolved_mdns_service(DNSServiceRef sdRef,
211 DNSServiceFlags flags,
212 uint32_t interfaceIndex,
213 DNSServiceErrorType errorCode,
214 const char* fullname,
215 const char* hosttarget,
216 uint16_t port,
217 uint16_t /*txtLen*/,
218 const unsigned char* /*txtRecord*/,
219 void* context) {
220 D("Resolved a service.");
221 std::unique_ptr<DiscoveredService> discovered(
222 reinterpret_cast<DiscoveredService*>(context));
223
224 if (errorCode != kDNSServiceErr_NoError) {
225 D("Got error %d resolving service.", errorCode);
226 return;
227 }
228
229
230 auto resolved =
231 new ResolvedService(discovered->ServiceName(),
232 interfaceIndex, hosttarget, ntohs(port));
233
234 if (! resolved->Initialized()) {
235 delete resolved;
236 }
237
238 if (flags) { /* Only ever equals MoreComing or 0 */
239 discovered.release();
240 }
241 }
242
register_mdns_transport(DNSServiceRef sdRef,DNSServiceFlags flags,uint32_t interfaceIndex,DNSServiceErrorType errorCode,const char * serviceName,const char * regtype,const char * domain,void *)243 static void DNSSD_API register_mdns_transport(DNSServiceRef sdRef,
244 DNSServiceFlags flags,
245 uint32_t interfaceIndex,
246 DNSServiceErrorType errorCode,
247 const char* serviceName,
248 const char* regtype,
249 const char* domain,
250 void* /*context*/) {
251 D("Registering a transport.");
252 if (errorCode != kDNSServiceErr_NoError) {
253 D("Got error %d during mDNS browse.", errorCode);
254 DNSServiceRefDeallocate(sdRef);
255 fdevent_remove(&service_ref_fde);
256 return;
257 }
258
259 auto discovered = new DiscoveredService(interfaceIndex, serviceName,
260 regtype, domain);
261
262 if (! discovered->Initialized()) {
263 delete discovered;
264 }
265 }
266
init_mdns_transport_discovery_thread(void)267 void init_mdns_transport_discovery_thread(void) {
268 DNSServiceErrorType errorCode = DNSServiceBrowse(&service_ref, 0, 0, kADBServiceType, nullptr,
269 register_mdns_transport, nullptr);
270
271 if (errorCode != kDNSServiceErr_NoError) {
272 D("Got %d initiating mDNS browse.", errorCode);
273 return;
274 }
275
276 fdevent_run_on_main_thread([]() {
277 fdevent_install(&service_ref_fde, adb_DNSServiceRefSockFD(service_ref), pump_service_ref,
278 &service_ref);
279 fdevent_set(&service_ref_fde, FDE_READ);
280 });
281 }
282
init_mdns_transport_discovery(void)283 void init_mdns_transport_discovery(void) {
284 std::thread(init_mdns_transport_discovery_thread).detach();
285 }
286