1/*
2 * Copyright (C) 2006 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#define LOG_TAG "InetAddress"
18
19#define LOG_DNS 0
20
21#include "JNIHelp.h"
22#include "utils/Log.h"
23#include "jni.h"
24
25#include <stdio.h>
26#include <string.h>
27#include <netdb.h>
28#include <errno.h>
29
30#include <netinet/in.h>
31#include <arpa/inet.h>
32#include <sys/socket.h>
33
34
35static jclass byteArrayClass = NULL;
36
37static jstring InetAddress_gethostname(JNIEnv* env, jobject obj)
38{
39    char name[256];
40    int r = gethostname(name, 256);
41    if (r == 0) {
42        return env->NewStringUTF(name);
43    } else {
44        return NULL;
45    }
46}
47
48#if LOG_DNS
49static void logIpString(struct addrinfo* ai, const char* name)
50{
51    char ipString[INET6_ADDRSTRLEN];
52    int result = getnameinfo(ai->ai_addr, ai->ai_addrlen, ipString,
53                             sizeof(ipString), NULL, 0, NI_NUMERICHOST);
54    if (result == 0) {
55        LOGD("%s: %s (family %d, proto %d)", name, ipString, ai->ai_family,
56             ai->ai_protocol);
57    } else {
58        LOGE("%s: getnameinfo: %s", name, gai_strerror(result));
59    }
60}
61#else
62static inline void logIpString(struct addrinfo* ai, const char* name)
63{
64}
65#endif
66
67static jobjectArray InetAddress_getaddrinfoImpl(JNIEnv* env, const char* name) {
68    struct addrinfo hints, *addressList = NULL, *addrInfo;
69    jobjectArray addressArray = NULL;
70
71    memset(&hints, 0, sizeof(hints));
72    hints.ai_family = AF_UNSPEC;
73    hints.ai_flags = AI_ADDRCONFIG;
74    /*
75     * If we don't specify a socket type, every address will appear twice, once
76     * for SOCK_STREAM and one for SOCK_DGRAM. Since we do not return the family
77     * anyway, just pick one.
78     */
79    hints.ai_socktype = SOCK_STREAM;
80
81    int result = getaddrinfo(name, NULL, &hints, &addressList);
82    if (result == 0 && addressList) {
83        // Count results so we know how to size the output array.
84        int addressCount = 0;
85        for (addrInfo = addressList; addrInfo; addrInfo = addrInfo->ai_next) {
86            if (addrInfo->ai_family == AF_INET ||
87                addrInfo->ai_family == AF_INET6) {
88                addressCount++;
89            }
90        }
91
92        // Prepare output array.
93        addressArray = env->NewObjectArray(addressCount, byteArrayClass, NULL);
94        if (addressArray == NULL) {
95            // Appropriate exception will be thrown.
96            LOGE("getaddrinfo: could not allocate array of size %i", addressCount);
97            freeaddrinfo(addrInfo);
98            return NULL;
99        }
100
101        // Examine returned addresses one by one, save them in the output array.
102        int index = 0;
103        for (addrInfo = addressList; addrInfo; addrInfo = addrInfo->ai_next) {
104            struct sockaddr* address = addrInfo->ai_addr;
105            size_t addressLength = 0;
106            void* rawAddress;
107
108            switch (addrInfo->ai_family) {
109                // Find the raw address length and start pointer.
110                case AF_INET6:
111                    addressLength = 16;
112                    rawAddress =
113                        &((struct sockaddr_in6*) address)->sin6_addr.s6_addr;
114                    logIpString(addrInfo, name);
115                    break;
116                case AF_INET:
117                    addressLength = 4;
118                    rawAddress =
119                        &((struct sockaddr_in*) address)->sin_addr.s_addr;
120                    logIpString(addrInfo, name);
121                    break;
122                default:
123                    // Unknown address family. Skip this address.
124                    LOGE("getaddrinfo: Unknown address family %d",
125                         addrInfo->ai_family);
126                    continue;
127            }
128
129            // Convert each IP address into a Java byte array.
130            jbyteArray bytearray = env->NewByteArray(addressLength);
131            if (bytearray == NULL) {
132                // Out of memory error will be thrown on return.
133                LOGE("getaddrinfo: Can't allocate %d-byte array",
134                     addressLength);
135                addressArray = NULL;
136                break;
137            }
138            env->SetByteArrayRegion(bytearray, 0, addressLength,
139                                    (jbyte*) rawAddress);
140            env->SetObjectArrayElement(addressArray, index, bytearray);
141            env->DeleteLocalRef(bytearray);
142            index++;
143        }
144    } else if (result == EAI_SYSTEM && errno == EACCES) {
145        /* No permission to use network */
146        jniThrowException(env, "java/lang/SecurityException",
147            "Permission denied (maybe missing INTERNET permission)");
148    } else {
149        jniThrowException(env, "java/net/UnknownHostException",
150                gai_strerror(result));
151    }
152
153    if (addressList) {
154        freeaddrinfo(addressList);
155    }
156
157    return addressArray;
158}
159
160jobjectArray InetAddress_getaddrinfo(JNIEnv* env, jobject obj, jstring javaName) {
161    if (javaName == NULL) {
162        jniThrowNullPointerException(env, NULL);
163        return NULL;
164    }
165    const char* name = env->GetStringUTFChars(javaName, NULL);
166    jobjectArray out = InetAddress_getaddrinfoImpl(env, name);
167    env->ReleaseStringUTFChars(javaName, name);
168    return out;
169}
170
171
172/**
173 * Looks up the name corresponding to an IP address.
174 *
175 * @param javaAddress: a byte array containing the raw IP address bytes. Must be
176 *         4 or 16 bytes long.
177 * @return the hostname.
178 * @throws UnknownHostException: the IP address has no associated hostname.
179 */
180static jstring InetAddress_getnameinfo(JNIEnv* env, jobject obj,
181                                         jbyteArray javaAddress)
182{
183    if (javaAddress == NULL) {
184        jniThrowNullPointerException(env, NULL);
185        return NULL;
186    }
187
188    // Convert the raw address bytes into a socket address structure.
189    struct sockaddr_storage ss;
190    memset(&ss, 0, sizeof(ss));
191
192    size_t socklen;
193    const size_t addressLength = env->GetArrayLength(javaAddress);
194    if (addressLength == 4) {
195        struct sockaddr_in* sin = reinterpret_cast<sockaddr_in*>(&ss);
196        sin->sin_family = AF_INET;
197        socklen = sizeof(struct sockaddr_in);
198        jbyte* dst = reinterpret_cast<jbyte*>(&sin->sin_addr.s_addr);
199        env->GetByteArrayRegion(javaAddress, 0, 4, dst);
200    } else if (addressLength == 16) {
201        struct sockaddr_in6 *sin6 = reinterpret_cast<sockaddr_in6*>(&ss);
202        sin6->sin6_family = AF_INET6;
203        socklen = sizeof(struct sockaddr_in6);
204        jbyte* dst = reinterpret_cast<jbyte*>(&sin6->sin6_addr.s6_addr);
205        env->GetByteArrayRegion(javaAddress, 0, 16, dst);
206    } else {
207        // The caller already throws an exception in this case. Don't worry
208        // about it here.
209        return NULL;
210    }
211
212    // Look up the host name from the IP address.
213    char name[NI_MAXHOST];
214    int ret = getnameinfo(reinterpret_cast<sockaddr*>(&ss), socklen,
215                          name, sizeof(name), NULL, 0, NI_NAMEREQD);
216    if (ret != 0) {
217        jniThrowException(env, "java/net/UnknownHostException", gai_strerror(ret));
218        return NULL;
219    }
220
221    return env->NewStringUTF(name);
222}
223
224/*
225 * JNI registration
226 */
227static JNINativeMethod gMethods[] = {
228    /* name, signature, funcPtr */
229    { "getaddrinfo", "(Ljava/lang/String;)[[B", (void*) InetAddress_getaddrinfo },
230    { "gethostname", "()Ljava/lang/String;", (void*) InetAddress_gethostname  },
231    { "getnameinfo", "([B)Ljava/lang/String;", (void*) InetAddress_getnameinfo },
232};
233
234extern "C" int register_java_net_InetAddress(JNIEnv* env) {
235    jclass tempClass = env->FindClass("[B");
236    if (tempClass) {
237        byteArrayClass = (jclass) env->NewGlobalRef(tempClass);
238    }
239    if (!byteArrayClass) {
240        LOGE("register_java_net_InetAddress: cannot allocate byte array class");
241        return -1;
242    }
243    return jniRegisterNativeMethods(env, "java/net/InetAddress",
244                gMethods, NELEM(gMethods));
245}
246