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[CLATJ#21] ClatCoordinator: start clatd

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launch clatd with the given cli arguments.

Bug: 212345928
Test: flash and boot
- run "atest ClatCoordinatorTest" in a follow commit.
- manual test
  1. Connect to ipv6-only wifi.
  2. Try IPv4 traffic.
     $ ping 8.8.8.8

Change-Id: Ie57a7c7a9d3d77396e91fa9f94c02f1ad05487c1
This commit is contained in:
Hungming Chen
2021-12-25 21:43:19 +08:00
parent eead25d263
commit 9625caa8e5
2 changed files with 139 additions and 15 deletions
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134
service/jni/com_android_server_connectivity_ClatCoordinator.cpp
View File

@@ -13,6 +13,7 @@
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#define LOG_TAG "jniClatCoordinator"
#include <arpa/inet.h>
#include <errno.h>
@@ -22,6 +23,7 @@
#include <log/log.h>
#include <nativehelper/JNIHelp.h>
#include <net/if.h>
#include <spawn.h>
#include <string>
#include <netjniutils/netjniutils.h>
@@ -33,9 +35,16 @@
// Sync from system/netd/include/netid_client.h
#define MARK_UNSET 0u
// Sync from system/netd/server/NetdConstants.h
#define __INT_STRLEN(i) sizeof(#i)
#define _INT_STRLEN(i) __INT_STRLEN(i)
#define INT32_STRLEN _INT_STRLEN(INT32_MIN)
#define DEVICEPREFIX "v4-"
namespace android {
static const char* kClatdPath = "/apex/com.android.tethering/bin/for-system/clatd";
static void throwIOException(JNIEnv* env, const char* msg, int error) {
jniThrowExceptionFmt(env, "java/io/IOException", "%s: %s", msg, strerror(error));
}
@@ -282,8 +291,7 @@ int initTracker(const std::string& iface, const std::string& pfx96, const std::s
return 0;
}
// TODO: fork clatd and rename to .._startClatd.
static jint com_android_server_connectivity_ClatCoordinator_maybeStartBpf(
static jint com_android_server_connectivity_ClatCoordinator_startClatd(
JNIEnv* env, jobject clazz, jobject tunJavaFd, jobject readSockJavaFd,
jobject writeSockJavaFd, jstring iface, jstring pfx96, jstring v4, jstring v6) {
ScopedUtfChars ifaceStr(env, iface);
@@ -291,7 +299,121 @@ static jint com_android_server_connectivity_ClatCoordinator_maybeStartBpf(
ScopedUtfChars v4Str(env, v4);
ScopedUtfChars v6Str(env, v6);
// Start BPF if any
int tunFd = netjniutils::GetNativeFileDescriptor(env, tunJavaFd);
if (tunFd < 0) {
jniThrowExceptionFmt(env, "java/io/IOException", "Invalid tun file descriptor");
return -1;
}
int readSock = netjniutils::GetNativeFileDescriptor(env, readSockJavaFd);
if (readSock < 0) {
jniThrowExceptionFmt(env, "java/io/IOException", "Invalid read socket");
return -1;
}
int writeSock = netjniutils::GetNativeFileDescriptor(env, writeSockJavaFd);
if (writeSock < 0) {
jniThrowExceptionFmt(env, "java/io/IOException", "Invalid write socket");
return -1;
}
// 1. create a throwaway socket to reserve a file descriptor number
int passedTunFd = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, 0);
if (passedTunFd == -1) {
throwIOException(env, "socket(ipv6/udp) for tun fd failed", errno);
return -1;
}
int passedSockRead = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, 0);
if (passedSockRead == -1) {
throwIOException(env, "socket(ipv6/udp) for read socket failed", errno);
return -1;
}
int passedSockWrite = socket(AF_INET6, SOCK_DGRAM | SOCK_CLOEXEC, 0);
if (passedSockWrite == -1) {
throwIOException(env, "socket(ipv6/udp) for write socket failed", errno);
return -1;
}
// these are the FD we'll pass to clatd on the cli, so need it as a string
char passedTunFdStr[INT32_STRLEN];
char passedSockReadStr[INT32_STRLEN];
char passedSockWriteStr[INT32_STRLEN];
snprintf(passedTunFdStr, sizeof(passedTunFdStr), "%d", passedTunFd);
snprintf(passedSockReadStr, sizeof(passedSockReadStr), "%d", passedSockRead);
snprintf(passedSockWriteStr, sizeof(passedSockWriteStr), "%d", passedSockWrite);
// 2. we're going to use this as argv[0] to clatd to make ps output more useful
std::string progname("clatd-");
progname += ifaceStr.c_str();
// clang-format off
const char* args[] = {progname.c_str(),
"-i", ifaceStr.c_str(),
"-p", pfx96Str.c_str(),
"-4", v4Str.c_str(),
"-6", v6Str.c_str(),
"-t", passedTunFdStr,
"-r", passedSockReadStr,
"-w", passedSockWriteStr,
nullptr};
// clang-format on
// 3. register vfork requirement
posix_spawnattr_t attr;
if (int ret = posix_spawnattr_init(&attr)) {
throwIOException(env, "posix_spawnattr_init failed", ret);
return -1;
}
// TODO: use android::base::ScopeGuard.
if (int ret = posix_spawnattr_setflags(&attr, POSIX_SPAWN_USEVFORK)) {
posix_spawnattr_destroy(&attr);
throwIOException(env, "posix_spawnattr_setflags failed", ret);
return -1;
}
// 4. register dup2() action: this is what 'clears' the CLOEXEC flag
// on the tun fd that we want the child clatd process to inherit
// (this will happen after the vfork, and before the execve)
posix_spawn_file_actions_t fa;
if (int ret = posix_spawn_file_actions_init(&fa)) {
posix_spawnattr_destroy(&attr);
throwIOException(env, "posix_spawn_file_actions_init failed", ret);
return -1;
}
if (int ret = posix_spawn_file_actions_adddup2(&fa, tunFd, passedTunFd)) {
posix_spawnattr_destroy(&attr);
posix_spawn_file_actions_destroy(&fa);
throwIOException(env, "posix_spawn_file_actions_adddup2 for tun fd failed", ret);
return -1;
}
if (int ret = posix_spawn_file_actions_adddup2(&fa, readSock, passedSockRead)) {
posix_spawnattr_destroy(&attr);
posix_spawn_file_actions_destroy(&fa);
throwIOException(env, "posix_spawn_file_actions_adddup2 for read socket failed", ret);
return -1;
}
if (int ret = posix_spawn_file_actions_adddup2(&fa, writeSock, passedSockWrite)) {
posix_spawnattr_destroy(&attr);
posix_spawn_file_actions_destroy(&fa);
throwIOException(env, "posix_spawn_file_actions_adddup2 for write socket failed", ret);
return -1;
}
// 5. actually perform vfork/dup2/execve
pid_t pid;
if (int ret = posix_spawn(&pid, kClatdPath, &fa, &attr, (char* const*)args, nullptr)) {
posix_spawnattr_destroy(&attr);
posix_spawn_file_actions_destroy(&fa);
throwIOException(env, "posix_spawn failed", ret);
return -1;
}
posix_spawnattr_destroy(&attr);
posix_spawn_file_actions_destroy(&fa);
// 5. Start BPF if any
if (!net::clat::initMaps()) {
net::clat::ClatdTracker tracker = {};
if (!initTracker(ifaceStr.c_str(), pfx96Str.c_str(), v4Str.c_str(), v6Str.c_str(),
@@ -300,7 +422,7 @@ static jint com_android_server_connectivity_ClatCoordinator_maybeStartBpf(
}
}
return 0; // TODO: return forked clatd pid.
return pid;
}
// TODO: stop clatd and rename to .._stopClatd.
@@ -344,10 +466,10 @@ static const JNINativeMethod gMethods[] = {
(void*)com_android_server_connectivity_ClatCoordinator_addAnycastSetsockopt},
{"native_configurePacketSocket", "(Ljava/io/FileDescriptor;Ljava/lang/String;I)V",
(void*)com_android_server_connectivity_ClatCoordinator_configurePacketSocket},
{"native_maybeStartBpf",
{"native_startClatd",
"(Ljava/io/FileDescriptor;Ljava/io/FileDescriptor;Ljava/io/FileDescriptor;Ljava/lang/"
"String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)I",
(void*)com_android_server_connectivity_ClatCoordinator_maybeStartBpf},
(void*)com_android_server_connectivity_ClatCoordinator_startClatd},
{"native_maybeStopBpf",
"(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;I)V",
(void*)com_android_server_connectivity_ClatCoordinator_maybeStopBpf},

20
service/src/com/android/server/connectivity/ClatCoordinator.java
View File

@@ -170,12 +170,12 @@ public class ClatCoordinator {
}
/**
* Maybe start bpf.
* Start clatd.
*/
public int maybeStartBpf(@NonNull FileDescriptor tunfd, @NonNull FileDescriptor readsock6,
public int startClatd(@NonNull FileDescriptor tunfd, @NonNull FileDescriptor readsock6,
@NonNull FileDescriptor writesock6, @NonNull String iface, @NonNull String pfx96,
@NonNull String v4, @NonNull String v6) throws IOException {
return native_maybeStartBpf(tunfd, readsock6, writesock6, iface, pfx96, v4, v6);
return native_startClatd(tunfd, readsock6, writesock6, iface, pfx96, v4, v6);
}
/**
@@ -219,6 +219,9 @@ public class ClatCoordinator {
public String clatStart(final String iface, final int netId,
@NonNull final IpPrefix nat64Prefix)
throws IOException {
if (mIface != null || mPid != INVALID_PID) {
throw new IOException("Clatd has started on " + mIface + " (pid " + mPid + ")");
}
if (nat64Prefix.getPrefixLength() != 96) {
throw new IOException("Prefix must be 96 bits long: " + nat64Prefix);
}
@@ -327,20 +330,19 @@ public class ClatCoordinator {
throw new IOException("configure packet socket failed: " + e);
}
// [5] Maybe start bpf.
// [5] Start clatd.
try {
mDeps.maybeStartBpf(tunFd.getFileDescriptor(), readSock6.getFileDescriptor(),
mPid = mDeps.startClatd(tunFd.getFileDescriptor(), readSock6.getFileDescriptor(),
writeSock6.getFileDescriptor(), iface, pfx96, v4, v6);
mIface = iface;
mNat64Prefix = pfx96;
mXlatLocalAddress4 = v4;
mXlatLocalAddress6 = v6;
} catch (IOException e) {
throw new IOException("Error start bpf on " + iface + ": " + e);
throw new IOException("Error start clatd on " + iface + ": " + e);
}
// TODO: start clatd and returns local xlat464 v6 address.
return null;
return v6;
}
/**
@@ -372,7 +374,7 @@ public class ClatCoordinator {
int ifindex) throws IOException;
private static native void native_configurePacketSocket(FileDescriptor sock, String v6,
int ifindex) throws IOException;
private static native int native_maybeStartBpf(FileDescriptor tunfd, FileDescriptor readsock6,
private static native int native_startClatd(FileDescriptor tunfd, FileDescriptor readsock6,
FileDescriptor writesock6, String iface, String pfx96, String v4, String v6)
throws IOException;
private static native void native_maybeStopBpf(String iface, String pfx96, String v4,