DnsProxyListener.cpp revision 3acdb064d8d5a86b1973fcda1e8dd83e0e12e0b3 
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#include <pthread.h>
28#include <resolv_iface.h>
29#include <net/if.h>
30
31#define LOG_TAG "DnsProxyListener"
32#define DBG 0
33#define VDBG 0
34
35#include <cutils/log.h>
36#include <sysutils/SocketClient.h>
37
38#include "DnsProxyListener.h"
39#include "ResponseCode.h"
40
41DnsProxyListener::DnsProxyListener() :
42                 FrameworkListener("dnsproxyd") {
43    registerCmd(new GetAddrInfoCmd());
44    registerCmd(new GetHostByAddrCmd());
45    registerCmd(new GetHostByNameCmd());
46}
47
48DnsProxyListener::GetAddrInfoHandler::GetAddrInfoHandler(SocketClient *c,
49                                                         char* host,
50                                                         char* service,
51                                                         struct addrinfo* hints,
52                                                         char* iface,
53                                                         pid_t pid,
54                                                         uid_t uid)
55        : mClient(c),
56          mHost(host),
57          mService(service),
58          mHints(hints),
59          mIface(iface),
60          mPid(pid),
61          mUid(uid) {
62}
63
64DnsProxyListener::GetAddrInfoHandler::~GetAddrInfoHandler() {
65    free(mHost);
66    free(mService);
67    free(mHints);
68    free(mIface);
69}
70
71void DnsProxyListener::GetAddrInfoHandler::start() {
72    pthread_t thread;
73    pthread_create(&thread, NULL,
74                   DnsProxyListener::GetAddrInfoHandler::threadStart, this);
75    pthread_detach(thread);
76}
77
78void* DnsProxyListener::GetAddrInfoHandler::threadStart(void* obj) {
79    GetAddrInfoHandler* handler = reinterpret_cast<GetAddrInfoHandler*>(obj);
80    handler->run();
81    delete handler;
82    pthread_exit(NULL);
83    return NULL;
84}
85
86// Sends 4 bytes of big-endian length, followed by the data.
87// Returns true on success.
88static bool sendLenAndData(SocketClient *c, const int len, const void* data) {
89    uint32_t len_be = htonl(len);
90    return c->sendData(&len_be, 4) == 0 &&
91        (len == 0 || c->sendData(data, len) == 0);
92}
93
94// Returns true on success
95static bool sendhostent(SocketClient *c, struct hostent *hp) {
96    bool success = true;
97    int i;
98    if (hp->h_name != NULL) {
99        success &= sendLenAndData(c, strlen(hp->h_name)+1, hp->h_name);
100    } else {
101        success &= sendLenAndData(c, 0, "") == 0;
102    }
103
104    for (i=0; hp->h_aliases[i] != NULL; i++) {
105        success &= sendLenAndData(c, strlen(hp->h_aliases[i])+1, hp->h_aliases[i]);
106    }
107    success &= sendLenAndData(c, 0, ""); // null to indicate we're done
108
109    uint32_t buf = htonl(hp->h_addrtype);
110    success &= c->sendData(&buf, sizeof(buf)) == 0;
111
112    buf = htonl(hp->h_length);
113    success &= c->sendData(&buf, sizeof(buf)) == 0;
114
115    for (i=0; hp->h_addr_list[i] != NULL; i++) {
116        success &= sendLenAndData(c, 16, hp->h_addr_list[i]);
117    }
118    success &= sendLenAndData(c, 0, ""); // null to indicate we're done
119    return success;
120}
121
122void DnsProxyListener::GetAddrInfoHandler::run() {
123    if (DBG) {
124        ALOGD("GetAddrInfoHandler, now for %s / %s / %s", mHost, mService, mIface);
125    }
126
127    char tmp[IF_NAMESIZE + 1];
128    if (mIface == NULL) {
129        //fall back to the per uid interface if no per pid interface exists
130        if(!_resolv_get_pids_associated_interface(mPid, tmp, sizeof(tmp)))
131            _resolv_get_uids_associated_interface(mUid, tmp, sizeof(tmp));
132    }
133
134    struct addrinfo* result = NULL;
135    uint32_t rv = android_getaddrinfoforiface(mHost, mService, mHints, mIface ? mIface : tmp,
136            &result);
137    if (rv) {
138        // getaddrinfo failed
139        mClient->sendBinaryMsg(ResponseCode::DnsProxyOperationFailed, &rv, sizeof(rv));
140    } else {
141        bool success = !mClient->sendCode(ResponseCode::DnsProxyQueryResult);
142        struct addrinfo* ai = result;
143        while (ai && success) {
144            success = sendLenAndData(mClient, sizeof(struct addrinfo), ai)
145                && sendLenAndData(mClient, ai->ai_addrlen, ai->ai_addr)
146                && sendLenAndData(mClient,
147                                  ai->ai_canonname ? strlen(ai->ai_canonname) + 1 : 0,
148                                  ai->ai_canonname);
149            ai = ai->ai_next;
150        }
151        success = success && sendLenAndData(mClient, 0, "");
152        if (!success) {
153            ALOGW("Error writing DNS result to client");
154        }
155    }
156    if (result) {
157        freeaddrinfo(result);
158    }
159    mClient->decRef();
160}
161
162DnsProxyListener::GetAddrInfoCmd::GetAddrInfoCmd() :
163    NetdCommand("getaddrinfo") {
164}
165
166int DnsProxyListener::GetAddrInfoCmd::runCommand(SocketClient *cli,
167                                            int argc, char **argv) {
168    if (DBG) {
169        for (int i = 0; i < argc; i++) {
170            ALOGD("argv[%i]=%s", i, argv[i]);
171        }
172    }
173    if (argc != 8) {
174        char* msg = NULL;
175        asprintf( &msg, "Invalid number of arguments to getaddrinfo: %i", argc);
176        ALOGW("%s", msg);
177        cli->sendMsg(ResponseCode::CommandParameterError, msg, false);
178        free(msg);
179        return -1;
180    }
181
182    char* name = argv[1];
183    if (strcmp("^", name) == 0) {
184        name = NULL;
185    } else {
186        name = strdup(name);
187    }
188
189    char* service = argv[2];
190    if (strcmp("^", service) == 0) {
191        service = NULL;
192    } else {
193        service = strdup(service);
194    }
195
196    char* iface = argv[7];
197    if (strcmp(iface, "^") == 0) {
198        iface = NULL;
199    } else {
200        iface = strdup(iface);
201    }
202
203    struct addrinfo* hints = NULL;
204    int ai_flags = atoi(argv[3]);
205    int ai_family = atoi(argv[4]);
206    int ai_socktype = atoi(argv[5]);
207    int ai_protocol = atoi(argv[6]);
208    pid_t pid = cli->getPid();
209    uid_t uid = cli->getUid();
210
211    if (ai_flags != -1 || ai_family != -1 ||
212        ai_socktype != -1 || ai_protocol != -1) {
213        hints = (struct addrinfo*) calloc(1, sizeof(struct addrinfo));
214        hints->ai_flags = ai_flags;
215        hints->ai_family = ai_family;
216        hints->ai_socktype = ai_socktype;
217        hints->ai_protocol = ai_protocol;
218    }
219
220    if (DBG) {
221        ALOGD("GetAddrInfoHandler for %s / %s / %s / %d / %d",
222             name ? name : "[nullhost]",
223             service ? service : "[nullservice]",
224             iface ? iface : "[nulliface]",
225             pid, uid);
226    }
227
228    cli->incRef();
229    DnsProxyListener::GetAddrInfoHandler* handler =
230        new DnsProxyListener::GetAddrInfoHandler(cli, name, service, hints, iface, pid, uid);
231    handler->start();
232
233    return 0;
234}
235
236/*******************************************************
237 *                  GetHostByName                      *
238 *******************************************************/
239DnsProxyListener::GetHostByNameCmd::GetHostByNameCmd() :
240        NetdCommand("gethostbyname") {
241}
242
243int DnsProxyListener::GetHostByNameCmd::runCommand(SocketClient *cli,
244                                            int argc, char **argv) {
245    if (DBG) {
246        for (int i = 0; i < argc; i++) {
247            ALOGD("argv[%i]=%s", i, argv[i]);
248        }
249    }
250    if (argc != 4) {
251        char* msg = NULL;
252        asprintf(&msg, "Invalid number of arguments to gethostbyname: %i", argc);
253        ALOGW("%s", msg);
254        cli->sendMsg(ResponseCode::CommandParameterError, msg, false);
255        free(msg);
256        return -1;
257    }
258
259    pid_t pid = cli->getPid();
260    uid_t uid = cli->getUid();
261    char* iface = argv[1];
262    char* name = argv[2];
263    int af = atoi(argv[3]);
264
265    if (strcmp(iface, "^") == 0) {
266        iface = NULL;
267    } else {
268        iface = strdup(iface);
269    }
270
271    if (strcmp(name, "^") == 0) {
272        name = NULL;
273    } else {
274        name = strdup(name);
275    }
276
277    cli->incRef();
278    DnsProxyListener::GetHostByNameHandler* handler =
279            new DnsProxyListener::GetHostByNameHandler(cli, pid, uid, iface, name, af);
280    handler->start();
281
282    return 0;
283}
284
285DnsProxyListener::GetHostByNameHandler::GetHostByNameHandler(SocketClient* c,
286                                                             pid_t pid,
287                                                             uid_t uid,
288                                                             char* iface,
289                                                             char* name,
290                                                             int af)
291        : mClient(c),
292          mPid(pid),
293          mUid(uid),
294          mIface(iface),
295          mName(name),
296          mAf(af) {
297}
298
299DnsProxyListener::GetHostByNameHandler::~GetHostByNameHandler() {
300    free(mIface);
301    free(mName);
302}
303
304void DnsProxyListener::GetHostByNameHandler::start() {
305    pthread_t thread;
306    pthread_create(&thread, NULL,
307            DnsProxyListener::GetHostByNameHandler::threadStart, this);
308    pthread_detach(thread);
309}
310
311void* DnsProxyListener::GetHostByNameHandler::threadStart(void* obj) {
312    GetHostByNameHandler* handler = reinterpret_cast<GetHostByNameHandler*>(obj);
313    handler->run();
314    delete handler;
315    pthread_exit(NULL);
316    return NULL;
317}
318
319void DnsProxyListener::GetHostByNameHandler::run() {
320    if (DBG) {
321        ALOGD("DnsProxyListener::GetHostByNameHandler::run\n");
322    }
323
324    char iface[IF_NAMESIZE + 1];
325    if (mIface == NULL) {
326        //fall back to the per uid interface if no per pid interface exists
327        if(!_resolv_get_pids_associated_interface(mPid, iface, sizeof(iface)))
328            _resolv_get_uids_associated_interface(mUid, iface, sizeof(iface));
329    }
330
331    struct hostent* hp;
332
333    hp = android_gethostbynameforiface(mName, mAf, mIface ? mIface : iface);
334
335    if (DBG) {
336        ALOGD("GetHostByNameHandler::run gethostbyname errno: %s hp->h_name = %s, name_len = %d\n",
337                hp ? "success" : strerror(errno),
338                (hp && hp->h_name) ? hp->h_name: "null",
339                (hp && hp->h_name) ? strlen(hp->h_name)+ 1 : 0);
340    }
341
342    bool success = true;
343    if (hp) {
344        success = mClient->sendCode(ResponseCode::DnsProxyQueryResult) == 0;
345        success &= sendhostent(mClient, hp);
346    } else {
347        success = mClient->sendBinaryMsg(ResponseCode::DnsProxyOperationFailed, NULL, 0) == 0;
348    }
349
350    if (!success) {
351        ALOGW("GetHostByNameHandler: Error writing DNS result to client\n");
352    }
353    mClient->decRef();
354}
355
356
357/*******************************************************
358 *                  GetHostByAddr                      *
359 *******************************************************/
360DnsProxyListener::GetHostByAddrCmd::GetHostByAddrCmd() :
361        NetdCommand("gethostbyaddr") {
362}
363
364int DnsProxyListener::GetHostByAddrCmd::runCommand(SocketClient *cli,
365                                            int argc, char **argv) {
366    if (DBG) {
367        for (int i = 0; i < argc; i++) {
368            ALOGD("argv[%i]=%s", i, argv[i]);
369        }
370    }
371    if (argc != 5) {
372        char* msg = NULL;
373        asprintf(&msg, "Invalid number of arguments to gethostbyaddr: %i", argc);
374        ALOGW("%s", msg);
375        cli->sendMsg(ResponseCode::CommandParameterError, msg, false);
376        free(msg);
377        return -1;
378    }
379
380    char* addrStr = argv[1];
381    int addrLen = atoi(argv[2]);
382    int addrFamily = atoi(argv[3]);
383    pid_t pid = cli->getPid();
384    uid_t uid = cli->getUid();
385    char* iface = argv[4];
386
387    if (strcmp(iface, "^") == 0) {
388        iface = NULL;
389    } else {
390        iface = strdup(iface);
391    }
392
393    void* addr = malloc(sizeof(struct in6_addr));
394    errno = 0;
395    int result = inet_pton(addrFamily, addrStr, addr);
396    if (result <= 0) {
397        char* msg = NULL;
398        asprintf(&msg, "inet_pton(\"%s\") failed %s", addrStr, strerror(errno));
399        ALOGW("%s", msg);
400        cli->sendMsg(ResponseCode::OperationFailed, msg, false);
401        free(addr);
402        free(msg);
403        return -1;
404    }
405
406    cli->incRef();
407    DnsProxyListener::GetHostByAddrHandler* handler =
408            new DnsProxyListener::GetHostByAddrHandler(cli, addr, addrLen, addrFamily, iface, pid, uid);
409    handler->start();
410
411    return 0;
412}
413
414DnsProxyListener::GetHostByAddrHandler::GetHostByAddrHandler(SocketClient* c,
415                                                             void* address,
416                                                             int   addressLen,
417                                                             int   addressFamily,
418                                                             char* iface,
419                                                             pid_t pid,
420                                                             uid_t uid)
421        : mClient(c),
422          mAddress(address),
423          mAddressLen(addressLen),
424          mAddressFamily(addressFamily),
425          mIface(iface),
426          mPid(pid),
427          mUid(uid) {
428}
429
430DnsProxyListener::GetHostByAddrHandler::~GetHostByAddrHandler() {
431    free(mAddress);
432    free(mIface);
433}
434
435void DnsProxyListener::GetHostByAddrHandler::start() {
436    pthread_t thread;
437    pthread_create(&thread, NULL,
438                   DnsProxyListener::GetHostByAddrHandler::threadStart, this);
439    pthread_detach(thread);
440}
441
442void* DnsProxyListener::GetHostByAddrHandler::threadStart(void* obj) {
443    GetHostByAddrHandler* handler = reinterpret_cast<GetHostByAddrHandler*>(obj);
444    handler->run();
445    delete handler;
446    pthread_exit(NULL);
447    return NULL;
448}
449
450void DnsProxyListener::GetHostByAddrHandler::run() {
451    if (DBG) {
452        ALOGD("DnsProxyListener::GetHostByAddrHandler::run\n");
453    }
454
455    char tmp[IF_NAMESIZE + 1];
456    if (mIface == NULL) {
457        //fall back to the per uid interface if no per pid interface exists
458        if(!_resolv_get_pids_associated_interface(mPid, tmp, sizeof(tmp)))
459            _resolv_get_uids_associated_interface(mUid, tmp, sizeof(tmp));
460    }
461    struct hostent* hp;
462
463    // NOTE gethostbyaddr should take a void* but bionic thinks it should be char*
464    hp = android_gethostbyaddrforiface((char*)mAddress, mAddressLen, mAddressFamily,
465            mIface ? mIface : tmp);
466
467    if (DBG) {
468        ALOGD("GetHostByAddrHandler::run gethostbyaddr errno: %s hp->h_name = %s, name_len = %d\n",
469                hp ? "success" : strerror(errno),
470                (hp && hp->h_name) ? hp->h_name: "null",
471                (hp && hp->h_name) ? strlen(hp->h_name)+ 1 : 0);
472    }
473
474    bool success = true;
475    if (hp) {
476        success = mClient->sendCode(ResponseCode::DnsProxyQueryResult) == 0;
477        success &= sendhostent(mClient, hp);
478    } else {
479        success = mClient->sendBinaryMsg(ResponseCode::DnsProxyOperationFailed, NULL, 0) == 0;
480    }
481
482    if (!success) {
483        ALOGW("GetHostByAddrHandler: Error writing DNS result to client\n");
484    }
485    mClient->decRef();
486}
487