DnsProxyListener.cpp revision e09b20aee85f1dfd8c18c3d8581ac875d939ba70 
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_netid.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 "Fwmark.h"
39#include "DnsProxyListener.h"
40#include "NetdConstants.h"
41#include "NetworkController.h"
42#include "ResponseCode.h"
43
44DnsProxyListener::DnsProxyListener(const NetworkController* netCtrl) :
45        FrameworkListener("dnsproxyd"), mNetCtrl(netCtrl) {
46    registerCmd(new GetAddrInfoCmd(this));
47    registerCmd(new GetHostByAddrCmd(this));
48    registerCmd(new GetHostByNameCmd(this));
49}
50
51uint32_t DnsProxyListener::calcMark(unsigned netId) const {
52    Fwmark fwmark;
53    fwmark.netId = netId;
54    fwmark.protectedFromVpn = true;
55    fwmark.permission = PERMISSION_SYSTEM;
56    return fwmark.intValue;
57}
58
59DnsProxyListener::GetAddrInfoHandler::GetAddrInfoHandler(SocketClient *c,
60                                                         char* host,
61                                                         char* service,
62                                                         struct addrinfo* hints,
63                                                         unsigned netId,
64                                                         uint32_t mark)
65        : mClient(c),
66          mHost(host),
67          mService(service),
68          mHints(hints),
69          mNetId(netId),
70          mMark(mark) {
71}
72
73DnsProxyListener::GetAddrInfoHandler::~GetAddrInfoHandler() {
74    free(mHost);
75    free(mService);
76    free(mHints);
77}
78
79void DnsProxyListener::GetAddrInfoHandler::start() {
80    pthread_t thread;
81    pthread_create(&thread, NULL,
82                   DnsProxyListener::GetAddrInfoHandler::threadStart, this);
83    pthread_detach(thread);
84}
85
86void* DnsProxyListener::GetAddrInfoHandler::threadStart(void* obj) {
87    GetAddrInfoHandler* handler = reinterpret_cast<GetAddrInfoHandler*>(obj);
88    handler->run();
89    delete handler;
90    pthread_exit(NULL);
91    return NULL;
92}
93
94// Sends 4 bytes of big-endian length, followed by the data.
95// Returns true on success.
96static bool sendLenAndData(SocketClient *c, const int len, const void* data) {
97    uint32_t len_be = htonl(len);
98    return c->sendData(&len_be, 4) == 0 &&
99        (len == 0 || c->sendData(data, len) == 0);
100}
101
102// Returns true on success
103static bool sendhostent(SocketClient *c, struct hostent *hp) {
104    bool success = true;
105    int i;
106    if (hp->h_name != NULL) {
107        success &= sendLenAndData(c, strlen(hp->h_name)+1, hp->h_name);
108    } else {
109        success &= sendLenAndData(c, 0, "") == 0;
110    }
111
112    for (i=0; hp->h_aliases[i] != NULL; i++) {
113        success &= sendLenAndData(c, strlen(hp->h_aliases[i])+1, hp->h_aliases[i]);
114    }
115    success &= sendLenAndData(c, 0, ""); // null to indicate we're done
116
117    uint32_t buf = htonl(hp->h_addrtype);
118    success &= c->sendData(&buf, sizeof(buf)) == 0;
119
120    buf = htonl(hp->h_length);
121    success &= c->sendData(&buf, sizeof(buf)) == 0;
122
123    for (i=0; hp->h_addr_list[i] != NULL; i++) {
124        success &= sendLenAndData(c, 16, hp->h_addr_list[i]);
125    }
126    success &= sendLenAndData(c, 0, ""); // null to indicate we're done
127    return success;
128}
129
130void DnsProxyListener::GetAddrInfoHandler::run() {
131    if (DBG) {
132        ALOGD("GetAddrInfoHandler, now for %s / %s / %u / %u", mHost, mService, mNetId, mMark);
133    }
134
135    struct addrinfo* result = NULL;
136    uint32_t rv = android_getaddrinfofornet(mHost, mService, mHints, mNetId, mMark, &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(const DnsProxyListener* dnsProxyListener) :
163    NetdCommand("getaddrinfo"),
164    mDnsProxyListener(dnsProxyListener) {
165}
166
167int DnsProxyListener::GetAddrInfoCmd::runCommand(SocketClient *cli,
168                                            int argc, char **argv) {
169    if (DBG) {
170        for (int i = 0; i < argc; i++) {
171            ALOGD("argv[%i]=%s", i, argv[i]);
172        }
173    }
174    if (argc != 8) {
175        char* msg = NULL;
176        asprintf( &msg, "Invalid number of arguments to getaddrinfo: %i", argc);
177        ALOGW("%s", msg);
178        cli->sendMsg(ResponseCode::CommandParameterError, msg, false);
179        free(msg);
180        return -1;
181    }
182
183    char* name = argv[1];
184    if (strcmp("^", name) == 0) {
185        name = NULL;
186    } else {
187        name = strdup(name);
188    }
189
190    char* service = argv[2];
191    if (strcmp("^", service) == 0) {
192        service = NULL;
193    } else {
194        service = strdup(service);
195    }
196
197    struct addrinfo* hints = NULL;
198    int ai_flags = atoi(argv[3]);
199    int ai_family = atoi(argv[4]);
200    int ai_socktype = atoi(argv[5]);
201    int ai_protocol = atoi(argv[6]);
202    unsigned netId = strtoul(argv[7], NULL, 10);
203    uid_t uid = cli->getUid();
204
205    netId = mDnsProxyListener->mNetCtrl->getNetworkForUser(uid, netId, true);
206    uint32_t mark = mDnsProxyListener->calcMark(netId);
207
208    if (ai_flags != -1 || ai_family != -1 ||
209        ai_socktype != -1 || ai_protocol != -1) {
210        hints = (struct addrinfo*) calloc(1, sizeof(struct addrinfo));
211        hints->ai_flags = ai_flags;
212        hints->ai_family = ai_family;
213        hints->ai_socktype = ai_socktype;
214        hints->ai_protocol = ai_protocol;
215
216        // Only implement AI_ADDRCONFIG if application is using default network since our
217        // implementation only works on the default network.
218        if ((hints->ai_flags & AI_ADDRCONFIG) &&
219                netId != mDnsProxyListener->mNetCtrl->getDefaultNetwork()) {
220            hints->ai_flags &= ~AI_ADDRCONFIG;
221        }
222    }
223
224    if (DBG) {
225        ALOGD("GetAddrInfoHandler for %s / %s / %u / %d / %u",
226             name ? name : "[nullhost]",
227             service ? service : "[nullservice]",
228             netId, uid, mark);
229    }
230
231    cli->incRef();
232    DnsProxyListener::GetAddrInfoHandler* handler =
233            new DnsProxyListener::GetAddrInfoHandler(cli, name, service, hints, netId, mark);
234    handler->start();
235
236    return 0;
237}
238
239/*******************************************************
240 *                  GetHostByName                      *
241 *******************************************************/
242DnsProxyListener::GetHostByNameCmd::GetHostByNameCmd(const DnsProxyListener* dnsProxyListener) :
243      NetdCommand("gethostbyname"),
244      mDnsProxyListener(dnsProxyListener) {
245}
246
247int DnsProxyListener::GetHostByNameCmd::runCommand(SocketClient *cli,
248                                            int argc, char **argv) {
249    if (DBG) {
250        for (int i = 0; i < argc; i++) {
251            ALOGD("argv[%i]=%s", i, argv[i]);
252        }
253    }
254    if (argc != 4) {
255        char* msg = NULL;
256        asprintf(&msg, "Invalid number of arguments to gethostbyname: %i", argc);
257        ALOGW("%s", msg);
258        cli->sendMsg(ResponseCode::CommandParameterError, msg, false);
259        free(msg);
260        return -1;
261    }
262
263    uid_t uid = cli->getUid();
264    unsigned netId = strtoul(argv[1], NULL, 10);
265    char* name = argv[2];
266    int af = atoi(argv[3]);
267
268    if (strcmp(name, "^") == 0) {
269        name = NULL;
270    } else {
271        name = strdup(name);
272    }
273
274    netId = mDnsProxyListener->mNetCtrl->getNetworkForUser(uid, netId, true);
275    uint32_t mark = mDnsProxyListener->calcMark(netId);
276
277    cli->incRef();
278    DnsProxyListener::GetHostByNameHandler* handler =
279            new DnsProxyListener::GetHostByNameHandler(cli, name, af, netId, mark);
280    handler->start();
281
282    return 0;
283}
284
285DnsProxyListener::GetHostByNameHandler::GetHostByNameHandler(SocketClient* c,
286                                                             char* name,
287                                                             int af,
288                                                             unsigned netId,
289                                                             uint32_t mark)
290        : mClient(c),
291          mName(name),
292          mAf(af),
293          mNetId(netId),
294          mMark(mark) {
295}
296
297DnsProxyListener::GetHostByNameHandler::~GetHostByNameHandler() {
298    free(mName);
299}
300
301void DnsProxyListener::GetHostByNameHandler::start() {
302    pthread_t thread;
303    pthread_create(&thread, NULL,
304            DnsProxyListener::GetHostByNameHandler::threadStart, this);
305    pthread_detach(thread);
306}
307
308void* DnsProxyListener::GetHostByNameHandler::threadStart(void* obj) {
309    GetHostByNameHandler* handler = reinterpret_cast<GetHostByNameHandler*>(obj);
310    handler->run();
311    delete handler;
312    pthread_exit(NULL);
313    return NULL;
314}
315
316void DnsProxyListener::GetHostByNameHandler::run() {
317    if (DBG) {
318        ALOGD("DnsProxyListener::GetHostByNameHandler::run\n");
319    }
320
321    struct hostent* hp;
322
323    hp = android_gethostbynamefornet(mName, mAf, mNetId, mMark);
324
325    if (DBG) {
326        ALOGD("GetHostByNameHandler::run gethostbyname errno: %s hp->h_name = %s, name_len = %zu\n",
327                hp ? "success" : strerror(errno),
328                (hp && hp->h_name) ? hp->h_name : "null",
329                (hp && hp->h_name) ? strlen(hp->h_name) + 1 : 0);
330    }
331
332    bool success = true;
333    if (hp) {
334        success = mClient->sendCode(ResponseCode::DnsProxyQueryResult) == 0;
335        success &= sendhostent(mClient, hp);
336    } else {
337        success = mClient->sendBinaryMsg(ResponseCode::DnsProxyOperationFailed, NULL, 0) == 0;
338    }
339
340    if (!success) {
341        ALOGW("GetHostByNameHandler: Error writing DNS result to client\n");
342    }
343    mClient->decRef();
344}
345
346
347/*******************************************************
348 *                  GetHostByAddr                      *
349 *******************************************************/
350DnsProxyListener::GetHostByAddrCmd::GetHostByAddrCmd(const DnsProxyListener* dnsProxyListener) :
351        NetdCommand("gethostbyaddr"),
352        mDnsProxyListener(dnsProxyListener) {
353}
354
355int DnsProxyListener::GetHostByAddrCmd::runCommand(SocketClient *cli,
356                                            int argc, char **argv) {
357    if (DBG) {
358        for (int i = 0; i < argc; i++) {
359            ALOGD("argv[%i]=%s", i, argv[i]);
360        }
361    }
362    if (argc != 5) {
363        char* msg = NULL;
364        asprintf(&msg, "Invalid number of arguments to gethostbyaddr: %i", argc);
365        ALOGW("%s", msg);
366        cli->sendMsg(ResponseCode::CommandParameterError, msg, false);
367        free(msg);
368        return -1;
369    }
370
371    char* addrStr = argv[1];
372    int addrLen = atoi(argv[2]);
373    int addrFamily = atoi(argv[3]);
374    uid_t uid = cli->getUid();
375    unsigned netId = strtoul(argv[4], NULL, 10);
376
377    void* addr = malloc(sizeof(struct in6_addr));
378    errno = 0;
379    int result = inet_pton(addrFamily, addrStr, addr);
380    if (result <= 0) {
381        char* msg = NULL;
382        asprintf(&msg, "inet_pton(\"%s\") failed %s", addrStr, strerror(errno));
383        ALOGW("%s", msg);
384        cli->sendMsg(ResponseCode::OperationFailed, msg, false);
385        free(addr);
386        free(msg);
387        return -1;
388    }
389
390    netId = mDnsProxyListener->mNetCtrl->getNetworkForUser(uid, netId, true);
391    uint32_t mark = mDnsProxyListener->calcMark(netId);
392
393    cli->incRef();
394    DnsProxyListener::GetHostByAddrHandler* handler =
395            new DnsProxyListener::GetHostByAddrHandler(cli, addr, addrLen, addrFamily, netId, mark);
396    handler->start();
397
398    return 0;
399}
400
401DnsProxyListener::GetHostByAddrHandler::GetHostByAddrHandler(SocketClient* c,
402                                                             void* address,
403                                                             int   addressLen,
404                                                             int   addressFamily,
405                                                             unsigned netId,
406                                                             uint32_t mark)
407        : mClient(c),
408          mAddress(address),
409          mAddressLen(addressLen),
410          mAddressFamily(addressFamily),
411          mNetId(netId),
412          mMark(mark) {
413}
414
415DnsProxyListener::GetHostByAddrHandler::~GetHostByAddrHandler() {
416    free(mAddress);
417}
418
419void DnsProxyListener::GetHostByAddrHandler::start() {
420    pthread_t thread;
421    pthread_create(&thread, NULL,
422                   DnsProxyListener::GetHostByAddrHandler::threadStart, this);
423    pthread_detach(thread);
424}
425
426void* DnsProxyListener::GetHostByAddrHandler::threadStart(void* obj) {
427    GetHostByAddrHandler* handler = reinterpret_cast<GetHostByAddrHandler*>(obj);
428    handler->run();
429    delete handler;
430    pthread_exit(NULL);
431    return NULL;
432}
433
434void DnsProxyListener::GetHostByAddrHandler::run() {
435    if (DBG) {
436        ALOGD("DnsProxyListener::GetHostByAddrHandler::run\n");
437    }
438    struct hostent* hp;
439
440    // NOTE gethostbyaddr should take a void* but bionic thinks it should be char*
441    hp = android_gethostbyaddrfornet((char*)mAddress, mAddressLen, mAddressFamily, mNetId, mMark);
442
443    if (DBG) {
444        ALOGD("GetHostByAddrHandler::run gethostbyaddr errno: %s hp->h_name = %s, name_len = %zu\n",
445                hp ? "success" : strerror(errno),
446                (hp && hp->h_name) ? hp->h_name : "null",
447                (hp && hp->h_name) ? strlen(hp->h_name) + 1 : 0);
448    }
449
450    bool success = true;
451    if (hp) {
452        success = mClient->sendCode(ResponseCode::DnsProxyQueryResult) == 0;
453        success &= sendhostent(mClient, hp);
454    } else {
455        success = mClient->sendBinaryMsg(ResponseCode::DnsProxyOperationFailed, NULL, 0) == 0;
456    }
457
458    if (!success) {
459        ALOGW("GetHostByAddrHandler: Error writing DNS result to client\n");
460    }
461    mClient->decRef();
462}
463