DnsProxyListener.cpp revision 007e987fee7e815e0c4bc820f434a632b7a69a9d 
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}
39
40DnsProxyListener::GetAddrInfoHandler::~GetAddrInfoHandler() {
41    free(mHost);
42    free(mService);
43    free(mHints);
44}
45
46void DnsProxyListener::GetAddrInfoHandler::start() {
47    pthread_create(&mThread, NULL,
48                   DnsProxyListener::GetAddrInfoHandler::threadStart, this);
49}
50
51void* DnsProxyListener::GetAddrInfoHandler::threadStart(void* obj) {
52    GetAddrInfoHandler* handler = reinterpret_cast<GetAddrInfoHandler*>(obj);
53    handler->run();
54    delete handler;
55    pthread_exit(NULL);
56    return NULL;
57}
58
59// Sends 4 bytes of big-endian length, followed by the data.
60// Returns true on success.
61static bool sendLenAndData(SocketClient *c, const int len, const void* data) {
62    uint32_t len_be = htonl(len);
63    return c->sendData(&len_be, 4) == 0 && c->sendData(data, len) == 0;
64}
65
66void DnsProxyListener::GetAddrInfoHandler::run() {
67    if (DBG) {
68        LOGD("GetAddrInfoHandler, now for %s / %s", mHost, mService);
69    }
70
71    struct addrinfo* result = NULL;
72    int rv = getaddrinfo(mHost, mService, mHints, &result);
73    bool success = mClient->sendData(&rv, sizeof(rv));
74    if (rv == 0) {
75        struct addrinfo* ai = result;
76        while (ai && success) {
77            success = sendLenAndData(mClient, sizeof(struct addrinfo), ai)
78                && sendLenAndData(mClient, ai->ai_addrlen, ai->ai_addr)
79                && sendLenAndData(mClient,
80                                  ai->ai_canonname ? strlen(ai->ai_canonname) + 1 : 0,
81                                  ai->ai_canonname);
82            ai = ai->ai_next;
83        }
84        success = success && sendLenAndData(mClient, 0, "");
85    }
86    if (result) {
87        freeaddrinfo(result);
88    }
89    if (!success) {
90        LOGW("Error writing DNS result to client");
91    }
92}
93
94DnsProxyListener::GetAddrInfoCmd::GetAddrInfoCmd() :
95    NetdCommand("getaddrinfo") {
96}
97
98int DnsProxyListener::GetAddrInfoCmd::runCommand(SocketClient *cli,
99                                            int argc, char **argv) {
100    if (argc != 7) {
101        LOGW("Invalid number of arguments to getaddrinfo");
102        return 0;
103    }
104
105    char* name = argv[1];
106    if (strcmp("^", name) == 0) {
107        name = NULL;
108    } else {
109        name = strdup(name);
110    }
111
112    char* service = argv[2];
113    if (strcmp("^", service) == 0) {
114        service = NULL;
115    } else {
116        service = strdup(service);
117    }
118
119    struct addrinfo* hints = NULL;
120    int ai_flags = atoi(argv[3]);
121    int ai_family = atoi(argv[4]);
122    int ai_socktype = atoi(argv[5]);
123    int ai_protocol = atoi(argv[6]);
124    if (ai_flags != -1 || ai_family != -1 ||
125        ai_socktype != -1 || ai_protocol != -1) {
126        hints = (struct addrinfo*) calloc(1, sizeof(struct addrinfo));
127        hints->ai_flags = ai_flags;
128        hints->ai_family = ai_family;
129        hints->ai_socktype = ai_socktype;
130        hints->ai_protocol = ai_protocol;
131    }
132
133    if (DBG) {
134        LOGD("GetAddrInfoHandler for %s / %s",
135             name ? name : "[nullhost]",
136             service ? service : "[nullservice]");
137    }
138
139    DnsProxyListener::GetAddrInfoHandler* handler =
140        new DnsProxyListener::GetAddrInfoHandler(cli, name, service, hints);
141    handler->start();
142
143
144    return 0;
145}
146