DnsProxyListener.cpp revision 6217272e1a41fc9827250c675a0499d2091ec6ac 
1/*
2 * Copyright (C) 2010 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#include <arpa/inet.h>
18#include <dirent.h>
19#include <errno.h>
20#include <linux/if.h>
21#include <netdb.h>
22#include <netinet/in.h>
23#include <stdlib.h>
24#include <sys/socket.h>
25#include <sys/types.h>
26#include <string.h>
27
28#define LOG_TAG "DnsProxyListener"
29#define DBG 0
30
31#include <cutils/log.h>
32#include <sysutils/SocketClient.h>
33
34#include "DnsProxyListener.h"
35#include "ResponseCode.h"
36
37DnsProxyListener::DnsProxyListener() :
38                 FrameworkListener("dnsproxyd") {
39    registerCmd(new GetAddrInfoCmd());
40    registerCmd(new GetHostByAddrCmd());
41}
42
43DnsProxyListener::GetAddrInfoHandler::~GetAddrInfoHandler() {
44    free(mHost);
45    free(mService);
46    free(mHints);
47}
48
49void DnsProxyListener::GetAddrInfoHandler::start() {
50    pthread_create(&mThread, NULL,
51                   DnsProxyListener::GetAddrInfoHandler::threadStart, this);
52}
53
54void* DnsProxyListener::GetAddrInfoHandler::threadStart(void* obj) {
55    GetAddrInfoHandler* handler = reinterpret_cast<GetAddrInfoHandler*>(obj);
56    handler->run();
57    delete handler;
58    pthread_exit(NULL);
59    return NULL;
60}
61
62// Sends 4 bytes of big-endian length, followed by the data.
63// Returns true on success.
64static bool sendLenAndData(SocketClient *c, const int len, const void* data) {
65    uint32_t len_be = htonl(len);
66    return c->sendData(&len_be, 4) == 0 &&
67        (len == 0 || c->sendData(data, len) == 0);
68}
69
70void DnsProxyListener::GetAddrInfoHandler::run() {
71    if (DBG) {
72        ALOGD("GetAddrInfoHandler, now for %s / %s", mHost, mService);
73    }
74
75    struct addrinfo* result = NULL;
76    uint32_t rv = getaddrinfo(mHost, mService, mHints, &result);
77    if (rv) {
78        // getaddrinfo failed
79        // TODO This is temporary. We think there is another bug exposed when we send data here, so
80        // temporarily setting it to 0.
81        mClient->sendBinaryMsg(ResponseCode::DnsProxyOperationFailed, &rv, 0);
82    } else {
83        bool success = !mClient->sendCode(ResponseCode::DnsProxyQueryResult);
84        struct addrinfo* ai = result;
85        while (ai && success) {
86            success = sendLenAndData(mClient, sizeof(struct addrinfo), ai)
87                && sendLenAndData(mClient, ai->ai_addrlen, ai->ai_addr)
88                && sendLenAndData(mClient,
89                                  ai->ai_canonname ? strlen(ai->ai_canonname) + 1 : 0,
90                                  ai->ai_canonname);
91            ai = ai->ai_next;
92        }
93        success = success && sendLenAndData(mClient, 0, "");
94        if (!success) {
95            ALOGW("Error writing DNS result to client");
96        }
97    }
98    if (result) {
99        freeaddrinfo(result);
100    }
101    mClient->decRef();
102}
103
104DnsProxyListener::GetAddrInfoCmd::GetAddrInfoCmd() :
105    NetdCommand("getaddrinfo") {
106}
107
108int DnsProxyListener::GetAddrInfoCmd::runCommand(SocketClient *cli,
109                                            int argc, char **argv) {
110    if (DBG) {
111        for (int i = 0; i < argc; i++) {
112            ALOGD("argv[%i]=%s", i, argv[i]);
113        }
114    }
115    if (argc != 7) {
116        char* msg = NULL;
117        asprintf( &msg, "Invalid number of arguments to getaddrinfo: %i", argc);
118        ALOGW("%s", msg);
119        cli->sendMsg(ResponseCode::CommandParameterError, msg, false);
120        free(msg);
121        return -1;
122    }
123
124    char* name = argv[1];
125    if (strcmp("^", name) == 0) {
126        name = NULL;
127    } else {
128        name = strdup(name);
129    }
130
131    char* service = argv[2];
132    if (strcmp("^", service) == 0) {
133        service = NULL;
134    } else {
135        service = strdup(service);
136    }
137
138    struct addrinfo* hints = NULL;
139    int ai_flags = atoi(argv[3]);
140    int ai_family = atoi(argv[4]);
141    int ai_socktype = atoi(argv[5]);
142    int ai_protocol = atoi(argv[6]);
143    if (ai_flags != -1 || ai_family != -1 ||
144        ai_socktype != -1 || ai_protocol != -1) {
145        hints = (struct addrinfo*) calloc(1, sizeof(struct addrinfo));
146        hints->ai_flags = ai_flags;
147        hints->ai_family = ai_family;
148        hints->ai_socktype = ai_socktype;
149        hints->ai_protocol = ai_protocol;
150    }
151
152    if (DBG) {
153        ALOGD("GetAddrInfoHandler for %s / %s",
154             name ? name : "[nullhost]",
155             service ? service : "[nullservice]");
156    }
157
158    cli->incRef();
159    DnsProxyListener::GetAddrInfoHandler* handler =
160        new DnsProxyListener::GetAddrInfoHandler(cli, name, service, hints);
161    handler->start();
162
163    return 0;
164}
165
166/*******************************************************
167 *                  GetHostByAddr                       *
168 *******************************************************/
169DnsProxyListener::GetHostByAddrCmd::GetHostByAddrCmd() :
170        NetdCommand("gethostbyaddr") {
171}
172
173int DnsProxyListener::GetHostByAddrCmd::runCommand(SocketClient *cli,
174                                            int argc, char **argv) {
175    if (DBG) {
176        for (int i = 0; i < argc; i++) {
177            ALOGD("argv[%i]=%s", i, argv[i]);
178        }
179    }
180
181    if (argc != 4) {
182        char* msg = NULL;
183        asprintf(&msg, "Invalid number of arguments to gethostbyaddr: %i", argc);
184        ALOGW("%s", msg);
185        cli->sendMsg(ResponseCode::CommandParameterError, msg, false);
186        free(msg);
187        return -1;
188    }
189
190    char* addrStr = argv[1];
191    int addrLen = atoi(argv[2]);
192    int addrFamily = atoi(argv[3]);
193
194    void* addr = malloc(sizeof(struct in6_addr));
195    errno = 0;
196    int result = inet_pton(addrFamily, addrStr, addr);
197    if (result <= 0) {
198        char* msg = NULL;
199        asprintf(&msg, "inet_pton(\"%s\") failed %s", addrStr, strerror(errno));
200        ALOGW("%s", msg);
201        cli->sendMsg(ResponseCode::OperationFailed, msg, false);
202        free(addr);
203        free(msg);
204        return -1;
205    }
206
207    cli->incRef();
208    DnsProxyListener::GetHostByAddrHandler* handler =
209            new DnsProxyListener::GetHostByAddrHandler(cli, addr, addrLen, addrFamily);
210    handler->start();
211
212    return 0;
213}
214
215DnsProxyListener::GetHostByAddrHandler::~GetHostByAddrHandler() {
216    free(mAddress);
217}
218
219void DnsProxyListener::GetHostByAddrHandler::start() {
220    pthread_create(&mThread, NULL,
221                   DnsProxyListener::GetHostByAddrHandler::threadStart, this);
222}
223
224void* DnsProxyListener::GetHostByAddrHandler::threadStart(void* obj) {
225    GetHostByAddrHandler* handler = reinterpret_cast<GetHostByAddrHandler*>(obj);
226    handler->run();
227    delete handler;
228    pthread_exit(NULL);
229    return NULL;
230}
231
232void DnsProxyListener::GetHostByAddrHandler::run() {
233    if (DBG) {
234        ALOGD("DnsProxyListener::GetHostByAddrHandler::run\n");
235    }
236
237    struct hostent* hp;
238
239    // NOTE gethostbyaddr should take a void* but bionic thinks it should be char*
240    hp = gethostbyaddr((char*)mAddress, mAddressLen, mAddressFamily);
241
242    if (DBG) {
243        ALOGD("GetHostByAddrHandler::run gethostbyaddr errno: %s hp->h_name = %s, name_len = %d\n",
244                hp ? "success" : strerror(errno),
245                (hp && hp->h_name) ? hp->h_name: "null",
246                (hp && hp->h_name) ? strlen(hp->h_name)+ 1 : 0);
247    }
248
249    bool failed = true;
250    if (hp) {
251        failed = mClient->sendBinaryMsg(ResponseCode::DnsProxyQueryResult,
252                                        hp->h_name ? hp->h_name : "",
253                                        hp->h_name ? strlen(hp->h_name)+ 1 : 0);
254    } else {
255        // TODO This is temporary. We think there is another bug exposed when we send data here, so
256        // temporarily setting it to 0.
257        uint32_t error = h_errno;
258        failed = mClient->sendBinaryMsg(ResponseCode::DnsProxyOperationFailed,
259                                        &error, 0);
260    }
261
262    if (failed) {
263        ALOGW("GetHostByAddrHandler: Error writing DNS result to client\n");
264    }
265    mClient->decRef();
266}
267