DnsProxyListener.cpp revision 6c798fbf4e89c4058f046a65ee4f9aa5647e43e1 
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 &&
64        (len == 0 || c->sendData(data, len) == 0);
65}
66
67void DnsProxyListener::GetAddrInfoHandler::run() {
68    if (DBG) {
69        LOGD("GetAddrInfoHandler, now for %s / %s", mHost, mService);
70    }
71
72    struct addrinfo* result = NULL;
73    int rv = getaddrinfo(mHost, mService, mHints, &result);
74    bool success = (mClient->sendData(&rv, sizeof(rv)) == 0);
75    if (rv == 0) {
76        struct addrinfo* ai = result;
77        while (ai && success) {
78            success = sendLenAndData(mClient, sizeof(struct addrinfo), ai)
79                && sendLenAndData(mClient, ai->ai_addrlen, ai->ai_addr)
80                && sendLenAndData(mClient,
81                                  ai->ai_canonname ? strlen(ai->ai_canonname) + 1 : 0,
82                                  ai->ai_canonname);
83            ai = ai->ai_next;
84        }
85        success = success && sendLenAndData(mClient, 0, "");
86    }
87    if (result) {
88        freeaddrinfo(result);
89    }
90    if (!success) {
91        LOGW("Error writing DNS result to client");
92    }
93}
94
95DnsProxyListener::GetAddrInfoCmd::GetAddrInfoCmd() :
96    NetdCommand("getaddrinfo") {
97}
98
99int DnsProxyListener::GetAddrInfoCmd::runCommand(SocketClient *cli,
100                                            int argc, char **argv) {
101    if (argc != 7) {
102        LOGW("Invalid number of arguments to getaddrinfo");
103        return 0;
104    }
105
106    char* name = argv[1];
107    if (strcmp("^", name) == 0) {
108        name = NULL;
109    } else {
110        name = strdup(name);
111    }
112
113    char* service = argv[2];
114    if (strcmp("^", service) == 0) {
115        service = NULL;
116    } else {
117        service = strdup(service);
118    }
119
120    struct addrinfo* hints = NULL;
121    int ai_flags = atoi(argv[3]);
122    int ai_family = atoi(argv[4]);
123    int ai_socktype = atoi(argv[5]);
124    int ai_protocol = atoi(argv[6]);
125    if (ai_flags != -1 || ai_family != -1 ||
126        ai_socktype != -1 || ai_protocol != -1) {
127        hints = (struct addrinfo*) calloc(1, sizeof(struct addrinfo));
128        hints->ai_flags = ai_flags;
129        hints->ai_family = ai_family;
130        hints->ai_socktype = ai_socktype;
131        hints->ai_protocol = ai_protocol;
132    }
133
134    if (DBG) {
135        LOGD("GetAddrInfoHandler for %s / %s",
136             name ? name : "[nullhost]",
137             service ? service : "[nullservice]");
138    }
139
140    DnsProxyListener::GetAddrInfoHandler* handler =
141        new DnsProxyListener::GetAddrInfoHandler(cli, name, service, hints);
142    handler->start();
143
144
145    return 0;
146}
147