DnsProxyListener.cpp revision 0475ae98cd8f45de815d67d1966edaf5997be9a9 
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
36DnsProxyListener::DnsProxyListener() :
37                 FrameworkListener("dnsproxyd") {
38    registerCmd(new GetAddrInfoCmd());
39    registerCmd(new GetHostByAddrCmd());
40}
41
42DnsProxyListener::GetAddrInfoHandler::~GetAddrInfoHandler() {
43    free(mHost);
44    free(mService);
45    free(mHints);
46}
47
48void DnsProxyListener::GetAddrInfoHandler::start() {
49    pthread_create(&mThread, NULL,
50                   DnsProxyListener::GetAddrInfoHandler::threadStart, this);
51}
52
53void* DnsProxyListener::GetAddrInfoHandler::threadStart(void* obj) {
54    GetAddrInfoHandler* handler = reinterpret_cast<GetAddrInfoHandler*>(obj);
55    handler->run();
56    delete handler;
57    pthread_exit(NULL);
58    return NULL;
59}
60
61// Sends 4 bytes of big-endian length, followed by the data.
62// Returns true on success.
63static bool sendLenAndData(SocketClient *c, const int len, const void* data) {
64    uint32_t len_be = htonl(len);
65    return c->sendData(&len_be, 4) == 0 &&
66        (len == 0 || c->sendData(data, len) == 0);
67}
68
69void DnsProxyListener::GetAddrInfoHandler::run() {
70    if (DBG) {
71        LOGD("GetAddrInfoHandler, now for %s / %s", mHost, mService);
72    }
73
74    struct addrinfo* result = NULL;
75    int rv = getaddrinfo(mHost, mService, mHints, &result);
76    bool success = (mClient->sendData(&rv, sizeof(rv)) == 0);
77    if (rv == 0) {
78        struct addrinfo* ai = result;
79        while (ai && success) {
80            success = sendLenAndData(mClient, sizeof(struct addrinfo), ai)
81                && sendLenAndData(mClient, ai->ai_addrlen, ai->ai_addr)
82                && sendLenAndData(mClient,
83                                  ai->ai_canonname ? strlen(ai->ai_canonname) + 1 : 0,
84                                  ai->ai_canonname);
85            ai = ai->ai_next;
86        }
87        success = success && sendLenAndData(mClient, 0, "");
88    }
89    if (result) {
90        freeaddrinfo(result);
91    }
92    if (!success) {
93        LOGW("Error writing DNS result to client");
94    }
95    mClient->decRef();
96}
97
98DnsProxyListener::GetAddrInfoCmd::GetAddrInfoCmd() :
99    NetdCommand("getaddrinfo") {
100}
101
102int DnsProxyListener::GetAddrInfoCmd::runCommand(SocketClient *cli,
103                                            int argc, char **argv) {
104    if (DBG) {
105        for (int i = 0; i < argc; i++) {
106            LOGD("argv[%i]=%s", i, argv[i]);
107        }
108    }
109    if (argc != 7) {
110        LOGW("Invalid number of arguments to getaddrinfo: %i", argc);
111        sendLenAndData(cli, 0, NULL);
112        return -1;
113    }
114
115    char* name = argv[1];
116    if (strcmp("^", name) == 0) {
117        name = NULL;
118    } else {
119        name = strdup(name);
120    }
121
122    char* service = argv[2];
123    if (strcmp("^", service) == 0) {
124        service = NULL;
125    } else {
126        service = strdup(service);
127    }
128
129    struct addrinfo* hints = NULL;
130    int ai_flags = atoi(argv[3]);
131    int ai_family = atoi(argv[4]);
132    int ai_socktype = atoi(argv[5]);
133    int ai_protocol = atoi(argv[6]);
134    if (ai_flags != -1 || ai_family != -1 ||
135        ai_socktype != -1 || ai_protocol != -1) {
136        hints = (struct addrinfo*) calloc(1, sizeof(struct addrinfo));
137        hints->ai_flags = ai_flags;
138        hints->ai_family = ai_family;
139        hints->ai_socktype = ai_socktype;
140        hints->ai_protocol = ai_protocol;
141    }
142
143    if (DBG) {
144        LOGD("GetAddrInfoHandler for %s / %s",
145             name ? name : "[nullhost]",
146             service ? service : "[nullservice]");
147    }
148
149    cli->incRef();
150    DnsProxyListener::GetAddrInfoHandler* handler =
151        new DnsProxyListener::GetAddrInfoHandler(cli, name, service, hints);
152    handler->start();
153
154    return 0;
155}
156
157/*******************************************************
158 *                  GetHostByAddr                       *
159 *******************************************************/
160DnsProxyListener::GetHostByAddrCmd::GetHostByAddrCmd() :
161        NetdCommand("gethostbyaddr") {
162}
163
164int DnsProxyListener::GetHostByAddrCmd::runCommand(SocketClient *cli,
165                                            int argc, char **argv) {
166    if (DBG) {
167        for (int i = 0; i < argc; i++) {
168            LOGD("argv[%i]=%s", i, argv[i]);
169        }
170    }
171    if (argc != 4) {
172        LOGW("Invalid number of arguments to gethostbyaddr: %i", argc);
173        sendLenAndData(cli, 0, NULL);
174        return -1;
175    }
176
177    char* addrStr = argv[1];
178    int addrLen = atoi(argv[2]);
179    int addrFamily = atoi(argv[3]);
180
181    void* addr = malloc(sizeof(struct in6_addr));
182    errno = 0;
183    int result = inet_pton(addrFamily, addrStr, addr);
184    if (result <= 0) {
185        LOGW("inet_pton(\"%s\") failed %s", addrStr, strerror(errno));
186        free(addr);
187        sendLenAndData(cli, 0, NULL);
188        return -1;
189    }
190
191    cli->incRef();
192    DnsProxyListener::GetHostByAddrHandler* handler =
193            new DnsProxyListener::GetHostByAddrHandler(cli, addr, addrLen, addrFamily);
194    handler->start();
195
196    return 0;
197}
198
199DnsProxyListener::GetHostByAddrHandler::~GetHostByAddrHandler() {
200    free(mAddress);
201}
202
203void DnsProxyListener::GetHostByAddrHandler::start() {
204    pthread_create(&mThread, NULL,
205                   DnsProxyListener::GetHostByAddrHandler::threadStart, this);
206}
207
208void* DnsProxyListener::GetHostByAddrHandler::threadStart(void* obj) {
209    GetHostByAddrHandler* handler = reinterpret_cast<GetHostByAddrHandler*>(obj);
210    handler->run();
211    delete handler;
212    pthread_exit(NULL);
213    return NULL;
214}
215
216void DnsProxyListener::GetHostByAddrHandler::run() {
217    if (DBG) {
218        LOGD("DnsProxyListener::GetHostByAddrHandler::run\n");
219    }
220
221    struct hostent* hp;
222
223    // NOTE gethostbyaddr should take a void* but bionic thinks it should be char*
224    hp = gethostbyaddr((char*)mAddress, mAddressLen, mAddressFamily);
225
226    if (DBG) {
227        LOGD("GetHostByAddrHandler::run gethostbyaddr errno: %s hp->h_name = %s, name_len = %d\n",
228                hp ? "success" : strerror(errno),
229                (hp && hp->h_name) ? hp->h_name: "null",
230                (hp && hp->h_name) ? strlen(hp->h_name)+ 1 : 0);
231    }
232
233    bool success = sendLenAndData(mClient, (hp && hp->h_name) ? strlen(hp->h_name)+ 1 : 0,
234            (hp && hp->h_name) ? hp->h_name : "");
235
236    if (!success) {
237        LOGW("GetHostByAddrHandler: Error writing DNS result to client\n");
238    }
239    mClient->decRef();
240}
241