DnsProxyListener.cpp revision cea2d3455eb7c0d9ad1430607cbe98cc09251c1f 
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
51DnsProxyListener::GetAddrInfoHandler::GetAddrInfoHandler(
52        SocketClient *c, char* host, char* service, struct addrinfo* hints,
53        const struct android_net_context& netcontext)
54        : mClient(c),
55          mHost(host),
56          mService(service),
57          mHints(hints),
58          mNetContext(netcontext) {
59}
60
61DnsProxyListener::GetAddrInfoHandler::~GetAddrInfoHandler() {
62    free(mHost);
63    free(mService);
64    free(mHints);
65}
66
67void DnsProxyListener::GetAddrInfoHandler::start() {
68    pthread_t thread;
69    pthread_create(&thread, NULL,
70                   DnsProxyListener::GetAddrInfoHandler::threadStart, this);
71    pthread_detach(thread);
72}
73
74void* DnsProxyListener::GetAddrInfoHandler::threadStart(void* obj) {
75    GetAddrInfoHandler* handler = reinterpret_cast<GetAddrInfoHandler*>(obj);
76    handler->run();
77    delete handler;
78    pthread_exit(NULL);
79    return NULL;
80}
81
82static bool sendBE32(SocketClient* c, uint32_t data) {
83    uint32_t be_data = htonl(data);
84    return c->sendData(&be_data, sizeof(be_data)) == 0;
85}
86
87// Sends 4 bytes of big-endian length, followed by the data.
88// Returns true on success.
89static bool sendLenAndData(SocketClient* c, const int len, const void* data) {
90    return sendBE32(c, len) && (len == 0 || c->sendData(data, len) == 0);
91}
92
93// Returns true on success
94static bool sendhostent(SocketClient *c, struct hostent *hp) {
95    bool success = true;
96    int i;
97    if (hp->h_name != NULL) {
98        success &= sendLenAndData(c, strlen(hp->h_name)+1, hp->h_name);
99    } else {
100        success &= sendLenAndData(c, 0, "") == 0;
101    }
102
103    for (i=0; hp->h_aliases[i] != NULL; i++) {
104        success &= sendLenAndData(c, strlen(hp->h_aliases[i])+1, hp->h_aliases[i]);
105    }
106    success &= sendLenAndData(c, 0, ""); // null to indicate we're done
107
108    uint32_t buf = htonl(hp->h_addrtype);
109    success &= c->sendData(&buf, sizeof(buf)) == 0;
110
111    buf = htonl(hp->h_length);
112    success &= c->sendData(&buf, sizeof(buf)) == 0;
113
114    for (i=0; hp->h_addr_list[i] != NULL; i++) {
115        success &= sendLenAndData(c, 16, hp->h_addr_list[i]);
116    }
117    success &= sendLenAndData(c, 0, ""); // null to indicate we're done
118    return success;
119}
120
121static bool sendaddrinfo(SocketClient* c, struct addrinfo* ai) {
122    // struct addrinfo {
123    //      int     ai_flags;       /* AI_PASSIVE, AI_CANONNAME, AI_NUMERICHOST */
124    //      int     ai_family;      /* PF_xxx */
125    //      int     ai_socktype;    /* SOCK_xxx */
126    //      int     ai_protocol;    /* 0 or IPPROTO_xxx for IPv4 and IPv6 */
127    //      socklen_t ai_addrlen;   /* length of ai_addr */
128    //      char    *ai_canonname;  /* canonical name for hostname */
129    //      struct  sockaddr *ai_addr;      /* binary address */
130    //      struct  addrinfo *ai_next;      /* next structure in linked list */
131    // };
132
133    // Write the struct piece by piece because we might be a 64-bit netd
134    // talking to a 32-bit process.
135    bool success =
136            sendBE32(c, ai->ai_flags) &&
137            sendBE32(c, ai->ai_family) &&
138            sendBE32(c, ai->ai_socktype) &&
139            sendBE32(c, ai->ai_protocol);
140    if (!success) {
141        return false;
142    }
143
144    // ai_addrlen and ai_addr.
145    if (!sendLenAndData(c, ai->ai_addrlen, ai->ai_addr)) {
146        return false;
147    }
148
149    // strlen(ai_canonname) and ai_canonname.
150    if (!sendLenAndData(c, ai->ai_canonname ? strlen(ai->ai_canonname) + 1 : 0, ai->ai_canonname)) {
151        return false;
152    }
153
154    return true;
155}
156
157void DnsProxyListener::GetAddrInfoHandler::run() {
158    if (DBG) {
159        ALOGD("GetAddrInfoHandler, now for %s / %s / {%u,%u,%u,%u,%u}", mHost, mService,
160                mNetContext.app_netid, mNetContext.app_mark,
161                mNetContext.dns_netid, mNetContext.dns_mark,
162                mNetContext.uid);
163    }
164
165    struct addrinfo* result = NULL;
166    uint32_t rv = android_getaddrinfofornetcontext(mHost, mService, mHints, &mNetContext, &result);
167    if (rv) {
168        // getaddrinfo failed
169        mClient->sendBinaryMsg(ResponseCode::DnsProxyOperationFailed, &rv, sizeof(rv));
170    } else {
171        bool success = !mClient->sendCode(ResponseCode::DnsProxyQueryResult);
172        struct addrinfo* ai = result;
173        while (ai && success) {
174            success = sendBE32(mClient, 1) && sendaddrinfo(mClient, ai);
175            ai = ai->ai_next;
176        }
177        success = success && sendBE32(mClient, 0);
178        if (!success) {
179            ALOGW("Error writing DNS result to client");
180        }
181    }
182    if (result) {
183        freeaddrinfo(result);
184    }
185    mClient->decRef();
186}
187
188DnsProxyListener::GetAddrInfoCmd::GetAddrInfoCmd(const DnsProxyListener* dnsProxyListener) :
189    NetdCommand("getaddrinfo"),
190    mDnsProxyListener(dnsProxyListener) {
191}
192
193int DnsProxyListener::GetAddrInfoCmd::runCommand(SocketClient *cli,
194                                            int argc, char **argv) {
195    if (DBG) {
196        for (int i = 0; i < argc; i++) {
197            ALOGD("argv[%i]=%s", i, argv[i]);
198        }
199    }
200    if (argc != 8) {
201        char* msg = NULL;
202        asprintf( &msg, "Invalid number of arguments to getaddrinfo: %i", argc);
203        ALOGW("%s", msg);
204        cli->sendMsg(ResponseCode::CommandParameterError, msg, false);
205        free(msg);
206        return -1;
207    }
208
209    char* name = argv[1];
210    if (strcmp("^", name) == 0) {
211        name = NULL;
212    } else {
213        name = strdup(name);
214    }
215
216    char* service = argv[2];
217    if (strcmp("^", service) == 0) {
218        service = NULL;
219    } else {
220        service = strdup(service);
221    }
222
223    struct addrinfo* hints = NULL;
224    int ai_flags = atoi(argv[3]);
225    int ai_family = atoi(argv[4]);
226    int ai_socktype = atoi(argv[5]);
227    int ai_protocol = atoi(argv[6]);
228    unsigned netId = strtoul(argv[7], NULL, 10);
229    uid_t uid = cli->getUid();
230
231    struct android_net_context netcontext;
232    mDnsProxyListener->mNetCtrl->getNetworkContext(netId, uid, &netcontext);
233
234    if (ai_flags != -1 || ai_family != -1 ||
235        ai_socktype != -1 || ai_protocol != -1) {
236        hints = (struct addrinfo*) calloc(1, sizeof(struct addrinfo));
237        hints->ai_flags = ai_flags;
238        hints->ai_family = ai_family;
239        hints->ai_socktype = ai_socktype;
240        hints->ai_protocol = ai_protocol;
241
242        // Only implement AI_ADDRCONFIG if application is using default network since our
243        // implementation only works on the default network.
244        if ((hints->ai_flags & AI_ADDRCONFIG) &&
245                netcontext.dns_netid != mDnsProxyListener->mNetCtrl->getDefaultNetwork()) {
246            hints->ai_flags &= ~AI_ADDRCONFIG;
247        }
248    }
249
250    if (DBG) {
251        ALOGD("GetAddrInfoHandler for %s / %s / {%u,%u,%u,%u,%u}",
252             name ? name : "[nullhost]",
253             service ? service : "[nullservice]",
254             netcontext.app_netid, netcontext.app_mark,
255             netcontext.dns_netid, netcontext.dns_mark,
256             netcontext.uid);
257    }
258
259    cli->incRef();
260    DnsProxyListener::GetAddrInfoHandler* handler =
261            new DnsProxyListener::GetAddrInfoHandler(cli, name, service, hints, netcontext);
262    handler->start();
263
264    return 0;
265}
266
267/*******************************************************
268 *                  GetHostByName                      *
269 *******************************************************/
270DnsProxyListener::GetHostByNameCmd::GetHostByNameCmd(const DnsProxyListener* dnsProxyListener) :
271      NetdCommand("gethostbyname"),
272      mDnsProxyListener(dnsProxyListener) {
273}
274
275int DnsProxyListener::GetHostByNameCmd::runCommand(SocketClient *cli,
276                                            int argc, char **argv) {
277    if (DBG) {
278        for (int i = 0; i < argc; i++) {
279            ALOGD("argv[%i]=%s", i, argv[i]);
280        }
281    }
282    if (argc != 4) {
283        char* msg = NULL;
284        asprintf(&msg, "Invalid number of arguments to gethostbyname: %i", argc);
285        ALOGW("%s", msg);
286        cli->sendMsg(ResponseCode::CommandParameterError, msg, false);
287        free(msg);
288        return -1;
289    }
290
291    uid_t uid = cli->getUid();
292    unsigned netId = strtoul(argv[1], NULL, 10);
293    char* name = argv[2];
294    int af = atoi(argv[3]);
295
296    if (strcmp(name, "^") == 0) {
297        name = NULL;
298    } else {
299        name = strdup(name);
300    }
301
302    uint32_t mark = mDnsProxyListener->mNetCtrl->getNetworkForDns(&netId, uid);
303
304    cli->incRef();
305    DnsProxyListener::GetHostByNameHandler* handler =
306            new DnsProxyListener::GetHostByNameHandler(cli, name, af, netId, mark);
307    handler->start();
308
309    return 0;
310}
311
312DnsProxyListener::GetHostByNameHandler::GetHostByNameHandler(SocketClient* c,
313                                                             char* name,
314                                                             int af,
315                                                             unsigned netId,
316                                                             uint32_t mark)
317        : mClient(c),
318          mName(name),
319          mAf(af),
320          mNetId(netId),
321          mMark(mark) {
322}
323
324DnsProxyListener::GetHostByNameHandler::~GetHostByNameHandler() {
325    free(mName);
326}
327
328void DnsProxyListener::GetHostByNameHandler::start() {
329    pthread_t thread;
330    pthread_create(&thread, NULL,
331            DnsProxyListener::GetHostByNameHandler::threadStart, this);
332    pthread_detach(thread);
333}
334
335void* DnsProxyListener::GetHostByNameHandler::threadStart(void* obj) {
336    GetHostByNameHandler* handler = reinterpret_cast<GetHostByNameHandler*>(obj);
337    handler->run();
338    delete handler;
339    pthread_exit(NULL);
340    return NULL;
341}
342
343void DnsProxyListener::GetHostByNameHandler::run() {
344    if (DBG) {
345        ALOGD("DnsProxyListener::GetHostByNameHandler::run\n");
346    }
347
348    struct hostent* hp;
349
350    hp = android_gethostbynamefornet(mName, mAf, mNetId, mMark);
351
352    if (DBG) {
353        ALOGD("GetHostByNameHandler::run gethostbyname errno: %s hp->h_name = %s, name_len = %zu\n",
354                hp ? "success" : strerror(errno),
355                (hp && hp->h_name) ? hp->h_name : "null",
356                (hp && hp->h_name) ? strlen(hp->h_name) + 1 : 0);
357    }
358
359    bool success = true;
360    if (hp) {
361        success = mClient->sendCode(ResponseCode::DnsProxyQueryResult) == 0;
362        success &= sendhostent(mClient, hp);
363    } else {
364        success = mClient->sendBinaryMsg(ResponseCode::DnsProxyOperationFailed, NULL, 0) == 0;
365    }
366
367    if (!success) {
368        ALOGW("GetHostByNameHandler: Error writing DNS result to client\n");
369    }
370    mClient->decRef();
371}
372
373
374/*******************************************************
375 *                  GetHostByAddr                      *
376 *******************************************************/
377DnsProxyListener::GetHostByAddrCmd::GetHostByAddrCmd(const DnsProxyListener* dnsProxyListener) :
378        NetdCommand("gethostbyaddr"),
379        mDnsProxyListener(dnsProxyListener) {
380}
381
382int DnsProxyListener::GetHostByAddrCmd::runCommand(SocketClient *cli,
383                                            int argc, char **argv) {
384    if (DBG) {
385        for (int i = 0; i < argc; i++) {
386            ALOGD("argv[%i]=%s", i, argv[i]);
387        }
388    }
389    if (argc != 5) {
390        char* msg = NULL;
391        asprintf(&msg, "Invalid number of arguments to gethostbyaddr: %i", argc);
392        ALOGW("%s", msg);
393        cli->sendMsg(ResponseCode::CommandParameterError, msg, false);
394        free(msg);
395        return -1;
396    }
397
398    char* addrStr = argv[1];
399    int addrLen = atoi(argv[2]);
400    int addrFamily = atoi(argv[3]);
401    uid_t uid = cli->getUid();
402    unsigned netId = strtoul(argv[4], NULL, 10);
403
404    void* addr = malloc(sizeof(struct in6_addr));
405    errno = 0;
406    int result = inet_pton(addrFamily, addrStr, addr);
407    if (result <= 0) {
408        char* msg = NULL;
409        asprintf(&msg, "inet_pton(\"%s\") failed %s", addrStr, strerror(errno));
410        ALOGW("%s", msg);
411        cli->sendMsg(ResponseCode::OperationFailed, msg, false);
412        free(addr);
413        free(msg);
414        return -1;
415    }
416
417    uint32_t mark = mDnsProxyListener->mNetCtrl->getNetworkForDns(&netId, uid);
418
419    cli->incRef();
420    DnsProxyListener::GetHostByAddrHandler* handler =
421            new DnsProxyListener::GetHostByAddrHandler(cli, addr, addrLen, addrFamily, netId, mark);
422    handler->start();
423
424    return 0;
425}
426
427DnsProxyListener::GetHostByAddrHandler::GetHostByAddrHandler(SocketClient* c,
428                                                             void* address,
429                                                             int   addressLen,
430                                                             int   addressFamily,
431                                                             unsigned netId,
432                                                             uint32_t mark)
433        : mClient(c),
434          mAddress(address),
435          mAddressLen(addressLen),
436          mAddressFamily(addressFamily),
437          mNetId(netId),
438          mMark(mark) {
439}
440
441DnsProxyListener::GetHostByAddrHandler::~GetHostByAddrHandler() {
442    free(mAddress);
443}
444
445void DnsProxyListener::GetHostByAddrHandler::start() {
446    pthread_t thread;
447    pthread_create(&thread, NULL,
448                   DnsProxyListener::GetHostByAddrHandler::threadStart, this);
449    pthread_detach(thread);
450}
451
452void* DnsProxyListener::GetHostByAddrHandler::threadStart(void* obj) {
453    GetHostByAddrHandler* handler = reinterpret_cast<GetHostByAddrHandler*>(obj);
454    handler->run();
455    delete handler;
456    pthread_exit(NULL);
457    return NULL;
458}
459
460void DnsProxyListener::GetHostByAddrHandler::run() {
461    if (DBG) {
462        ALOGD("DnsProxyListener::GetHostByAddrHandler::run\n");
463    }
464    struct hostent* hp;
465
466    // NOTE gethostbyaddr should take a void* but bionic thinks it should be char*
467    hp = android_gethostbyaddrfornet((char*)mAddress, mAddressLen, mAddressFamily, mNetId, mMark);
468
469    if (DBG) {
470        ALOGD("GetHostByAddrHandler::run gethostbyaddr errno: %s hp->h_name = %s, name_len = %zu\n",
471                hp ? "success" : strerror(errno),
472                (hp && hp->h_name) ? hp->h_name : "null",
473                (hp && hp->h_name) ? strlen(hp->h_name) + 1 : 0);
474    }
475
476    bool success = true;
477    if (hp) {
478        success = mClient->sendCode(ResponseCode::DnsProxyQueryResult) == 0;
479        success &= sendhostent(mClient, hp);
480    } else {
481        success = mClient->sendBinaryMsg(ResponseCode::DnsProxyOperationFailed, NULL, 0) == 0;
482    }
483
484    if (!success) {
485        ALOGW("GetHostByAddrHandler: Error writing DNS result to client\n");
486    }
487    mClient->decRef();
488}
489