DnsProxyListener.cpp revision 40e0c13d6b77a9260b6da4c9e11cca8a5f994ea2 
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        mClient->sendBinaryMsg(ResponseCode::DnsProxyOperationFailed, &rv, sizeof(rv));
80    } else {
81        bool success = !mClient->sendCode(ResponseCode::DnsProxyQueryResult);
82        struct addrinfo* ai = result;
83        while (ai && success) {
84            success = sendLenAndData(mClient, sizeof(struct addrinfo), ai)
85                && sendLenAndData(mClient, ai->ai_addrlen, ai->ai_addr)
86                && sendLenAndData(mClient,
87                                  ai->ai_canonname ? strlen(ai->ai_canonname) + 1 : 0,
88                                  ai->ai_canonname);
89            ai = ai->ai_next;
90        }
91        success = success && sendLenAndData(mClient, 0, "");
92        if (!success) {
93            ALOGW("Error writing DNS result to client");
94        }
95    }
96    if (result) {
97        freeaddrinfo(result);
98    }
99    mClient->decRef();
100}
101
102DnsProxyListener::GetAddrInfoCmd::GetAddrInfoCmd() :
103    NetdCommand("getaddrinfo") {
104}
105
106int DnsProxyListener::GetAddrInfoCmd::runCommand(SocketClient *cli,
107                                            int argc, char **argv) {
108    if (DBG) {
109        for (int i = 0; i < argc; i++) {
110            ALOGD("argv[%i]=%s", i, argv[i]);
111        }
112    }
113    if (argc != 7) {
114        char* msg = NULL;
115        asprintf( &msg, "Invalid number of arguments to getaddrinfo: %i", argc);
116        ALOGW("%s", msg);
117        cli->sendMsg(ResponseCode::CommandParameterError, msg, false);
118        free(msg);
119        return -1;
120    }
121
122    char* name = argv[1];
123    if (strcmp("^", name) == 0) {
124        name = NULL;
125    } else {
126        name = strdup(name);
127    }
128
129    char* service = argv[2];
130    if (strcmp("^", service) == 0) {
131        service = NULL;
132    } else {
133        service = strdup(service);
134    }
135
136    struct addrinfo* hints = NULL;
137    int ai_flags = atoi(argv[3]);
138    int ai_family = atoi(argv[4]);
139    int ai_socktype = atoi(argv[5]);
140    int ai_protocol = atoi(argv[6]);
141    if (ai_flags != -1 || ai_family != -1 ||
142        ai_socktype != -1 || ai_protocol != -1) {
143        hints = (struct addrinfo*) calloc(1, sizeof(struct addrinfo));
144        hints->ai_flags = ai_flags;
145        hints->ai_family = ai_family;
146        hints->ai_socktype = ai_socktype;
147        hints->ai_protocol = ai_protocol;
148    }
149
150    if (DBG) {
151        ALOGD("GetAddrInfoHandler for %s / %s",
152             name ? name : "[nullhost]",
153             service ? service : "[nullservice]");
154    }
155
156    cli->incRef();
157    DnsProxyListener::GetAddrInfoHandler* handler =
158        new DnsProxyListener::GetAddrInfoHandler(cli, name, service, hints);
159    handler->start();
160
161    return 0;
162}
163
164/*******************************************************
165 *                  GetHostByAddr                       *
166 *******************************************************/
167DnsProxyListener::GetHostByAddrCmd::GetHostByAddrCmd() :
168        NetdCommand("gethostbyaddr") {
169}
170
171int DnsProxyListener::GetHostByAddrCmd::runCommand(SocketClient *cli,
172                                            int argc, char **argv) {
173    if (DBG) {
174        for (int i = 0; i < argc; i++) {
175            ALOGD("argv[%i]=%s", i, argv[i]);
176        }
177    }
178
179    if (argc != 4) {
180        char* msg = NULL;
181        asprintf(&msg, "Invalid number of arguments to gethostbyaddr: %i", argc);
182        ALOGW("%s", msg);
183        cli->sendMsg(ResponseCode::CommandParameterError, msg, false);
184        free(msg);
185        return -1;
186    }
187
188    char* addrStr = argv[1];
189    int addrLen = atoi(argv[2]);
190    int addrFamily = atoi(argv[3]);
191
192    void* addr = malloc(sizeof(struct in6_addr));
193    errno = 0;
194    int result = inet_pton(addrFamily, addrStr, addr);
195    if (result <= 0) {
196        char* msg = NULL;
197        asprintf(&msg, "inet_pton(\"%s\") failed %s", addrStr, strerror(errno));
198        ALOGW("%s", msg);
199        cli->sendMsg(ResponseCode::OperationFailed, msg, false);
200        free(addr);
201        free(msg);
202        return -1;
203    }
204
205    cli->incRef();
206    DnsProxyListener::GetHostByAddrHandler* handler =
207            new DnsProxyListener::GetHostByAddrHandler(cli, addr, addrLen, addrFamily);
208    handler->start();
209
210    return 0;
211}
212
213DnsProxyListener::GetHostByAddrHandler::~GetHostByAddrHandler() {
214    free(mAddress);
215}
216
217void DnsProxyListener::GetHostByAddrHandler::start() {
218    pthread_create(&mThread, NULL,
219                   DnsProxyListener::GetHostByAddrHandler::threadStart, this);
220}
221
222void* DnsProxyListener::GetHostByAddrHandler::threadStart(void* obj) {
223    GetHostByAddrHandler* handler = reinterpret_cast<GetHostByAddrHandler*>(obj);
224    handler->run();
225    delete handler;
226    pthread_exit(NULL);
227    return NULL;
228}
229
230void DnsProxyListener::GetHostByAddrHandler::run() {
231    if (DBG) {
232        ALOGD("DnsProxyListener::GetHostByAddrHandler::run\n");
233    }
234
235    struct hostent* hp;
236
237    // NOTE gethostbyaddr should take a void* but bionic thinks it should be char*
238    hp = gethostbyaddr((char*)mAddress, mAddressLen, mAddressFamily);
239
240    if (DBG) {
241        ALOGD("GetHostByAddrHandler::run gethostbyaddr errno: %s hp->h_name = %s, name_len = %d\n",
242                hp ? "success" : strerror(errno),
243                (hp && hp->h_name) ? hp->h_name: "null",
244                (hp && hp->h_name) ? strlen(hp->h_name)+ 1 : 0);
245    }
246
247    bool failed = true;
248    if (hp) {
249        failed = mClient->sendBinaryMsg(ResponseCode::DnsProxyQueryResult,
250                                        hp->h_name ? hp->h_name : "",
251                                        hp->h_name ? strlen(hp->h_name)+ 1 : 0);
252    } else {
253        uint32_t error = h_errno;
254        failed = mClient->sendBinaryMsg(ResponseCode::DnsProxyOperationFailed,
255                                        &error, sizeof(error));
256    }
257
258    if (failed) {
259        ALOGW("GetHostByAddrHandler: Error writing DNS result to client\n");
260    }
261    mClient->decRef();
262}
263