DnsProxyListener.cpp revision 5c6d6af88f9db03493ef9926e0ceab30c8b132c9 
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
27#define LOG_TAG "DnsProxyListener"
28#define DBG 0
29
30#include <cutils/log.h>
31#include <sysutils/SocketClient.h>
32
33#include "DnsProxyListener.h"
34
35DnsProxyListener::DnsProxyListener() :
36                 FrameworkListener("dnsproxyd") {
37    registerCmd(new GetAddrInfoCmd());
38    registerCmd(new GetHostByAddrCmd());
39}
40
41DnsProxyListener::GetAddrInfoHandler::~GetAddrInfoHandler() {
42    free(mHost);
43    free(mService);
44    free(mHints);
45}
46
47void DnsProxyListener::GetAddrInfoHandler::start() {
48    pthread_create(&mThread, NULL,
49                   DnsProxyListener::GetAddrInfoHandler::threadStart, this);
50}
51
52void* DnsProxyListener::GetAddrInfoHandler::threadStart(void* obj) {
53    GetAddrInfoHandler* handler = reinterpret_cast<GetAddrInfoHandler*>(obj);
54    handler->run();
55    delete handler;
56    pthread_exit(NULL);
57    return NULL;
58}
59
60// Sends 4 bytes of big-endian length, followed by the data.
61// Returns true on success.
62static bool sendLenAndData(SocketClient *c, const int len, const void* data) {
63    uint32_t len_be = htonl(len);
64    return c->sendData(&len_be, 4) == 0 &&
65        (len == 0 || c->sendData(data, len) == 0);
66}
67
68void DnsProxyListener::GetAddrInfoHandler::run() {
69    if (DBG) {
70        LOGD("GetAddrInfoHandler, now for %s / %s", mHost, mService);
71    }
72
73    struct addrinfo* result = NULL;
74    int rv = getaddrinfo(mHost, mService, mHints, &result);
75    bool success = (mClient->sendData(&rv, sizeof(rv)) == 0);
76    if (rv == 0) {
77        struct addrinfo* ai = result;
78        while (ai && success) {
79            success = sendLenAndData(mClient, sizeof(struct addrinfo), ai)
80                && sendLenAndData(mClient, ai->ai_addrlen, ai->ai_addr)
81                && sendLenAndData(mClient,
82                                  ai->ai_canonname ? strlen(ai->ai_canonname) + 1 : 0,
83                                  ai->ai_canonname);
84            ai = ai->ai_next;
85        }
86        success = success && sendLenAndData(mClient, 0, "");
87    }
88    if (result) {
89        freeaddrinfo(result);
90    }
91    if (!success) {
92        LOGW("Error writing DNS result to client");
93    }
94}
95
96DnsProxyListener::GetAddrInfoCmd::GetAddrInfoCmd() :
97    NetdCommand("getaddrinfo") {
98}
99
100int DnsProxyListener::GetAddrInfoCmd::runCommand(SocketClient *cli,
101                                            int argc, char **argv) {
102    if (DBG) {
103        for (int i = 0; i < argc; i++) {
104            LOGD("argv[%i]=%s", i, argv[i]);
105        }
106    }
107    if (argc != 7) {
108        LOGW("Invalid number of arguments to getaddrinfo: %i", argc);
109        sendLenAndData(cli, 0, NULL);
110        return -1;
111    }
112
113    char* name = argv[1];
114    if (strcmp("^", name) == 0) {
115        name = NULL;
116    } else {
117        name = strdup(name);
118    }
119
120    char* service = argv[2];
121    if (strcmp("^", service) == 0) {
122        service = NULL;
123    } else {
124        service = strdup(service);
125    }
126
127    struct addrinfo* hints = NULL;
128    int ai_flags = atoi(argv[3]);
129    int ai_family = atoi(argv[4]);
130    int ai_socktype = atoi(argv[5]);
131    int ai_protocol = atoi(argv[6]);
132    if (ai_flags != -1 || ai_family != -1 ||
133        ai_socktype != -1 || ai_protocol != -1) {
134        hints = (struct addrinfo*) calloc(1, sizeof(struct addrinfo));
135        hints->ai_flags = ai_flags;
136        hints->ai_family = ai_family;
137        hints->ai_socktype = ai_socktype;
138        hints->ai_protocol = ai_protocol;
139    }
140
141    if (DBG) {
142        LOGD("GetAddrInfoHandler for %s / %s",
143             name ? name : "[nullhost]",
144             service ? service : "[nullservice]");
145    }
146
147    DnsProxyListener::GetAddrInfoHandler* handler =
148        new DnsProxyListener::GetAddrInfoHandler(cli, name, service, hints);
149    handler->start();
150
151
152    return 0;
153}
154
155/*******************************************************
156 *                  GetHostByAddr                       *
157 *******************************************************/
158DnsProxyListener::GetHostByAddrCmd::GetHostByAddrCmd() :
159        NetdCommand("gethostbyaddr") {
160}
161
162int DnsProxyListener::GetHostByAddrCmd::runCommand(SocketClient *cli,
163                                            int argc, char **argv) {
164    if (DBG) {
165        for (int i = 0; i < argc; i++) {
166            LOGD("argv[%i]=%s", i, argv[i]);
167        }
168    }
169    if (argc != 4) {
170        LOGW("Invalid number of arguments to gethostbyaddr: %i", argc);
171        sendLenAndData(cli, 0, NULL);
172        return -1;
173    }
174
175    char* addrStr = argv[1];
176    int addrLen = atoi(argv[2]);
177    int addrFamily = atoi(argv[3]);
178
179    void* addr = malloc(sizeof(struct in6_addr));
180    errno = 0;
181    int result = inet_pton(addrFamily, addrStr, addr);
182    if (result <= 0) {
183        LOGW("inet_pton(\"%s\") failed %s", addrStr, strerror(errno));
184        free(addr);
185        sendLenAndData(cli, 0, NULL);
186        return -1;
187    }
188
189    DnsProxyListener::GetHostByAddrHandler* handler =
190            new DnsProxyListener::GetHostByAddrHandler(cli, addr, addrLen, addrFamily);
191    handler->start();
192
193    return 0;
194}
195
196DnsProxyListener::GetHostByAddrHandler::~GetHostByAddrHandler() {
197    free(mAddress);
198}
199
200void DnsProxyListener::GetHostByAddrHandler::start() {
201    pthread_create(&mThread, NULL,
202                   DnsProxyListener::GetHostByAddrHandler::threadStart, this);
203}
204
205void* DnsProxyListener::GetHostByAddrHandler::threadStart(void* obj) {
206    GetHostByAddrHandler* handler = reinterpret_cast<GetHostByAddrHandler*>(obj);
207    handler->run();
208    delete handler;
209    pthread_exit(NULL);
210    return NULL;
211}
212
213void DnsProxyListener::GetHostByAddrHandler::run() {
214    if (DBG) {
215        LOGD("DnsProxyListener::GetHostByAddrHandler::run\n");
216    }
217
218    struct hostent* hp;
219
220    // NOTE gethostbyaddr should take a void* but bionic thinks it should be char*
221    hp = gethostbyaddr((char*)mAddress, mAddressLen, mAddressFamily);
222
223    if (DBG) {
224        LOGD("GetHostByAddrHandler::run gethostbyaddr errno: %s hp->h_name = %s, name_len = %d\n",
225                hp ? "success" : strerror(errno),
226                (hp && hp->h_name) ? hp->h_name: "null",
227                (hp && hp->h_name) ? strlen(hp->h_name)+ 1 : 0);
228    }
229
230    bool success = sendLenAndData(mClient, (hp && hp->h_name) ? strlen(hp->h_name)+ 1 : 0,
231            (hp && hp->h_name) ? hp->h_name : "");
232
233    if (!success) {
234        LOGW("GetHostByAddrHandler: Error writing DNS result to client\n");
235    }
236}
237