/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <arpa/inet.h>
#include <dirent.h>
#include <errno.h>
#include <linux/if.h>
#include <math.h>
#include <netdb.h>
#include <netinet/in.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <string.h>
#include <pthread.h>
#include <resolv_netid.h>
#include <net/if.h>
#define LOG_TAG "DnsProxyListener"
#define DBG 0
#define VDBG 0
#include <chrono>
#include <cutils/log.h>
#include <binder/IServiceManager.h>
#include <utils/String16.h>
#include <sysutils/SocketClient.h>
#include "Fwmark.h"
#include "DnsProxyListener.h"
#include "NetdConstants.h"
#include "NetworkController.h"
#include "ResponseCode.h"
#include "android/net/metrics/IDnsEventListener.h"
using android::String16;
using android::interface_cast;
using android::net::metrics::IDnsEventListener;
DnsProxyListener::DnsProxyListener(const NetworkController* netCtrl) :
FrameworkListener("dnsproxyd"), mNetCtrl(netCtrl) {
registerCmd(new GetAddrInfoCmd(this));
registerCmd(new GetHostByAddrCmd(this));
registerCmd(new GetHostByNameCmd(this));
}
DnsProxyListener::GetAddrInfoHandler::GetAddrInfoHandler(
SocketClient *c, char* host, char* service, struct addrinfo* hints,
const struct android_net_context& netcontext,
const android::sp<android::net::metrics::IDnsEventListener>& dnsEventListener)
: mClient(c),
mHost(host),
mService(service),
mHints(hints),
mNetContext(netcontext),
mDnsEventListener(dnsEventListener) {
}
DnsProxyListener::GetAddrInfoHandler::~GetAddrInfoHandler() {
free(mHost);
free(mService);
free(mHints);
}
void DnsProxyListener::GetAddrInfoHandler::start() {
pthread_t thread;
pthread_create(&thread, NULL,
DnsProxyListener::GetAddrInfoHandler::threadStart, this);
pthread_detach(thread);
}
void* DnsProxyListener::GetAddrInfoHandler::threadStart(void* obj) {
GetAddrInfoHandler* handler = reinterpret_cast<GetAddrInfoHandler*>(obj);
handler->run();
delete handler;
pthread_exit(NULL);
return NULL;
}
android::sp<IDnsEventListener> DnsProxyListener::getDnsEventListener() {
if (mDnsEventListener == nullptr) {
// Use checkService instead of getService because getService waits for 5 seconds for the
// service to become available. The DNS resolver inside netd is started much earlier in the
// boot sequence than the framework DNS listener, and we don't want to delay all DNS lookups
// for 5 seconds until the DNS listener starts up.
android::sp<android::IBinder> b = android::defaultServiceManager()->checkService(
android::String16("dns_listener"));
if (b != nullptr) {
mDnsEventListener = interface_cast<IDnsEventListener>(b);
}
}
// If the DNS listener service is dead, the binder call will just return an error, which should
// be fine because the only impact is that we can't log DNS events. In any case, this should
// only happen if the system server is going down, which means it will shortly be taking us down
// with it.
return mDnsEventListener;
}
static bool sendBE32(SocketClient* c, uint32_t data) {
uint32_t be_data = htonl(data);
return c->sendData(&be_data, sizeof(be_data)) == 0;
}
// Sends 4 bytes of big-endian length, followed by the data.
// Returns true on success.
static bool sendLenAndData(SocketClient* c, const int len, const void* data) {
return sendBE32(c, len) && (len == 0 || c->sendData(data, len) == 0);
}
// Returns true on success
static bool sendhostent(SocketClient *c, struct hostent *hp) {
bool success = true;
int i;
if (hp->h_name != NULL) {
success &= sendLenAndData(c, strlen(hp->h_name)+1, hp->h_name);
} else {
success &= sendLenAndData(c, 0, "") == 0;
}
for (i=0; hp->h_aliases[i] != NULL; i++) {
success &= sendLenAndData(c, strlen(hp->h_aliases[i])+1, hp->h_aliases[i]);
}
success &= sendLenAndData(c, 0, ""); // null to indicate we're done
uint32_t buf = htonl(hp->h_addrtype);
success &= c->sendData(&buf, sizeof(buf)) == 0;
buf = htonl(hp->h_length);
success &= c->sendData(&buf, sizeof(buf)) == 0;
for (i=0; hp->h_addr_list[i] != NULL; i++) {
success &= sendLenAndData(c, 16, hp->h_addr_list[i]);
}
success &= sendLenAndData(c, 0, ""); // null to indicate we're done
return success;
}
static bool sendaddrinfo(SocketClient* c, struct addrinfo* ai) {
// struct addrinfo {
// int ai_flags; /* AI_PASSIVE, AI_CANONNAME, AI_NUMERICHOST */
// int ai_family; /* PF_xxx */
// int ai_socktype; /* SOCK_xxx */
// int ai_protocol; /* 0 or IPPROTO_xxx for IPv4 and IPv6 */
// socklen_t ai_addrlen; /* length of ai_addr */
// char *ai_canonname; /* canonical name for hostname */
// struct sockaddr *ai_addr; /* binary address */
// struct addrinfo *ai_next; /* next structure in linked list */
// };
// Write the struct piece by piece because we might be a 64-bit netd
// talking to a 32-bit process.
bool success =
sendBE32(c, ai->ai_flags) &&
sendBE32(c, ai->ai_family) &&
sendBE32(c, ai->ai_socktype) &&
sendBE32(c, ai->ai_protocol);
if (!success) {
return false;
}
// ai_addrlen and ai_addr.
if (!sendLenAndData(c, ai->ai_addrlen, ai->ai_addr)) {
return false;
}
// strlen(ai_canonname) and ai_canonname.
if (!sendLenAndData(c, ai->ai_canonname ? strlen(ai->ai_canonname) + 1 : 0, ai->ai_canonname)) {
return false;
}
return true;
}
void DnsProxyListener::GetAddrInfoHandler::run() {
if (DBG) {
ALOGD("GetAddrInfoHandler, now for %s / %s / {%u,%u,%u,%u,%u}", mHost, mService,
mNetContext.app_netid, mNetContext.app_mark,
mNetContext.dns_netid, mNetContext.dns_mark,
mNetContext.uid);
}
struct addrinfo* result = NULL;
Stopwatch s;
uint32_t rv = android_getaddrinfofornetcontext(mHost, mService, mHints, &mNetContext, &result);
const int latencyMs = lround(s.timeTaken());
if (rv) {
// getaddrinfo failed
mClient->sendBinaryMsg(ResponseCode::DnsProxyOperationFailed, &rv, sizeof(rv));
} else {
bool success = !mClient->sendCode(ResponseCode::DnsProxyQueryResult);
struct addrinfo* ai = result;
while (ai && success) {
success = sendBE32(mClient, 1) && sendaddrinfo(mClient, ai);
ai = ai->ai_next;
}
success = success && sendBE32(mClient, 0);
if (!success) {
ALOGW("Error writing DNS result to client");
}
}
if (result) {
freeaddrinfo(result);
}
mClient->decRef();
if (mDnsEventListener != nullptr) {
mDnsEventListener->onDnsEvent(mNetContext.dns_netid, IDnsEventListener::EVENT_GETADDRINFO,
(int32_t) rv, latencyMs);
}
}
DnsProxyListener::GetAddrInfoCmd::GetAddrInfoCmd(DnsProxyListener* dnsProxyListener) :
NetdCommand("getaddrinfo"),
mDnsProxyListener(dnsProxyListener) {
}
int DnsProxyListener::GetAddrInfoCmd::runCommand(SocketClient *cli,
int argc, char **argv) {
if (DBG) {
for (int i = 0; i < argc; i++) {
ALOGD("argv[%i]=%s", i, argv[i]);
}
}
if (argc != 8) {
char* msg = NULL;
asprintf( &msg, "Invalid number of arguments to getaddrinfo: %i", argc);
ALOGW("%s", msg);
cli->sendMsg(ResponseCode::CommandParameterError, msg, false);
free(msg);
return -1;
}
char* name = argv[1];
if (strcmp("^", name) == 0) {
name = NULL;
} else {
name = strdup(name);
}
char* service = argv[2];
if (strcmp("^", service) == 0) {
service = NULL;
} else {
service = strdup(service);
}
struct addrinfo* hints = NULL;
int ai_flags = atoi(argv[3]);
int ai_family = atoi(argv[4]);
int ai_socktype = atoi(argv[5]);
int ai_protocol = atoi(argv[6]);
unsigned netId = strtoul(argv[7], NULL, 10);
uid_t uid = cli->getUid();
struct android_net_context netcontext;
mDnsProxyListener->mNetCtrl->getNetworkContext(netId, uid, &netcontext);
if (ai_flags != -1 || ai_family != -1 ||
ai_socktype != -1 || ai_protocol != -1) {
hints = (struct addrinfo*) calloc(1, sizeof(struct addrinfo));
hints->ai_flags = ai_flags;
hints->ai_family = ai_family;
hints->ai_socktype = ai_socktype;
hints->ai_protocol = ai_protocol;
}
if (DBG) {
ALOGD("GetAddrInfoHandler for %s / %s / {%u,%u,%u,%u,%u}",
name ? name : "[nullhost]",
service ? service : "[nullservice]",
netcontext.app_netid, netcontext.app_mark,
netcontext.dns_netid, netcontext.dns_mark,
netcontext.uid);
}
cli->incRef();
DnsProxyListener::GetAddrInfoHandler* handler =
new DnsProxyListener::GetAddrInfoHandler(cli, name, service, hints, netcontext,
mDnsProxyListener->getDnsEventListener());
handler->start();
return 0;
}
/*******************************************************
* GetHostByName *
*******************************************************/
DnsProxyListener::GetHostByNameCmd::GetHostByNameCmd(DnsProxyListener* dnsProxyListener) :
NetdCommand("gethostbyname"),
mDnsProxyListener(dnsProxyListener) {
}
int DnsProxyListener::GetHostByNameCmd::runCommand(SocketClient *cli,
int argc, char **argv) {
if (DBG) {
for (int i = 0; i < argc; i++) {
ALOGD("argv[%i]=%s", i, argv[i]);
}
}
if (argc != 4) {
char* msg = NULL;
asprintf(&msg, "Invalid number of arguments to gethostbyname: %i", argc);
ALOGW("%s", msg);
cli->sendMsg(ResponseCode::CommandParameterError, msg, false);
free(msg);
return -1;
}
uid_t uid = cli->getUid();
unsigned netId = strtoul(argv[1], NULL, 10);
char* name = argv[2];
int af = atoi(argv[3]);
if (strcmp(name, "^") == 0) {
name = NULL;
} else {
name = strdup(name);
}
uint32_t mark = mDnsProxyListener->mNetCtrl->getNetworkForDns(&netId, uid);
cli->incRef();
DnsProxyListener::GetHostByNameHandler* handler =
new DnsProxyListener::GetHostByNameHandler(cli, name, af, netId, mark,
mDnsProxyListener->getDnsEventListener());
handler->start();
return 0;
}
DnsProxyListener::GetHostByNameHandler::GetHostByNameHandler(
SocketClient* c, char* name, int af, unsigned netId, uint32_t mark,
const android::sp<android::net::metrics::IDnsEventListener>& dnsEventListener)
: mClient(c),
mName(name),
mAf(af),
mNetId(netId),
mMark(mark),
mDnsEventListener(dnsEventListener) {
}
DnsProxyListener::GetHostByNameHandler::~GetHostByNameHandler() {
free(mName);
}
void DnsProxyListener::GetHostByNameHandler::start() {
pthread_t thread;
pthread_create(&thread, NULL,
DnsProxyListener::GetHostByNameHandler::threadStart, this);
pthread_detach(thread);
}
void* DnsProxyListener::GetHostByNameHandler::threadStart(void* obj) {
GetHostByNameHandler* handler = reinterpret_cast<GetHostByNameHandler*>(obj);
handler->run();
delete handler;
pthread_exit(NULL);
return NULL;
}
void DnsProxyListener::GetHostByNameHandler::run() {
if (DBG) {
ALOGD("DnsProxyListener::GetHostByNameHandler::run\n");
}
Stopwatch s;
struct hostent* hp = android_gethostbynamefornet(mName, mAf, mNetId, mMark);
const int latencyMs = lround(s.timeTaken());
if (DBG) {
ALOGD("GetHostByNameHandler::run gethostbyname errno: %s hp->h_name = %s, name_len = %zu\n",
hp ? "success" : strerror(errno),
(hp && hp->h_name) ? hp->h_name : "null",
(hp && hp->h_name) ? strlen(hp->h_name) + 1 : 0);
}
bool success = true;
if (hp) {
success = mClient->sendCode(ResponseCode::DnsProxyQueryResult) == 0;
success &= sendhostent(mClient, hp);
} else {
success = mClient->sendBinaryMsg(ResponseCode::DnsProxyOperationFailed, NULL, 0) == 0;
}
if (!success) {
ALOGW("GetHostByNameHandler: Error writing DNS result to client\n");
}
mClient->decRef();
if (mDnsEventListener != nullptr) {
mDnsEventListener->onDnsEvent(mNetId, IDnsEventListener::EVENT_GETHOSTBYNAME,
h_errno, latencyMs);
}
}
/*******************************************************
* GetHostByAddr *
*******************************************************/
DnsProxyListener::GetHostByAddrCmd::GetHostByAddrCmd(const DnsProxyListener* dnsProxyListener) :
NetdCommand("gethostbyaddr"),
mDnsProxyListener(dnsProxyListener) {
}
int DnsProxyListener::GetHostByAddrCmd::runCommand(SocketClient *cli,
int argc, char **argv) {
if (DBG) {
for (int i = 0; i < argc; i++) {
ALOGD("argv[%i]=%s", i, argv[i]);
}
}
if (argc != 5) {
char* msg = NULL;
asprintf(&msg, "Invalid number of arguments to gethostbyaddr: %i", argc);
ALOGW("%s", msg);
cli->sendMsg(ResponseCode::CommandParameterError, msg, false);
free(msg);
return -1;
}
char* addrStr = argv[1];
int addrLen = atoi(argv[2]);
int addrFamily = atoi(argv[3]);
uid_t uid = cli->getUid();
unsigned netId = strtoul(argv[4], NULL, 10);
void* addr = malloc(sizeof(struct in6_addr));
errno = 0;
int result = inet_pton(addrFamily, addrStr, addr);
if (result <= 0) {
char* msg = NULL;
asprintf(&msg, "inet_pton(\"%s\") failed %s", addrStr, strerror(errno));
ALOGW("%s", msg);
cli->sendMsg(ResponseCode::OperationFailed, msg, false);
free(addr);
free(msg);
return -1;
}
uint32_t mark = mDnsProxyListener->mNetCtrl->getNetworkForDns(&netId, uid);
cli->incRef();
DnsProxyListener::GetHostByAddrHandler* handler =
new DnsProxyListener::GetHostByAddrHandler(cli, addr, addrLen, addrFamily, netId, mark);
handler->start();
return 0;
}
DnsProxyListener::GetHostByAddrHandler::GetHostByAddrHandler(SocketClient* c,
void* address,
int addressLen,
int addressFamily,
unsigned netId,
uint32_t mark)
: mClient(c),
mAddress(address),
mAddressLen(addressLen),
mAddressFamily(addressFamily),
mNetId(netId),
mMark(mark) {
}
DnsProxyListener::GetHostByAddrHandler::~GetHostByAddrHandler() {
free(mAddress);
}
void DnsProxyListener::GetHostByAddrHandler::start() {
pthread_t thread;
pthread_create(&thread, NULL,
DnsProxyListener::GetHostByAddrHandler::threadStart, this);
pthread_detach(thread);
}
void* DnsProxyListener::GetHostByAddrHandler::threadStart(void* obj) {
GetHostByAddrHandler* handler = reinterpret_cast<GetHostByAddrHandler*>(obj);
handler->run();
delete handler;
pthread_exit(NULL);
return NULL;
}
void DnsProxyListener::GetHostByAddrHandler::run() {
if (DBG) {
ALOGD("DnsProxyListener::GetHostByAddrHandler::run\n");
}
struct hostent* hp;
// NOTE gethostbyaddr should take a void* but bionic thinks it should be char*
hp = android_gethostbyaddrfornet((char*)mAddress, mAddressLen, mAddressFamily, mNetId, mMark);
if (DBG) {
ALOGD("GetHostByAddrHandler::run gethostbyaddr errno: %s hp->h_name = %s, name_len = %zu\n",
hp ? "success" : strerror(errno),
(hp && hp->h_name) ? hp->h_name : "null",
(hp && hp->h_name) ? strlen(hp->h_name) + 1 : 0);
}
bool success = true;
if (hp) {
success = mClient->sendCode(ResponseCode::DnsProxyQueryResult) == 0;
success &= sendhostent(mClient, hp);
} else {
success = mClient->sendBinaryMsg(ResponseCode::DnsProxyOperationFailed, NULL, 0) == 0;
}
if (!success) {
ALOGW("GetHostByAddrHandler: Error writing DNS result to client\n");
}
mClient->decRef();
}