Merge changes If27bffb5,I945e650b

* changes:
  libbinder: RpcAddress is uint64_t
  libbinder: Session ID implemented directly.
diff --git a/libs/binder/Android.bp b/libs/binder/Android.bp
index fccc9fa..b0d7478 100644
--- a/libs/binder/Android.bp
+++ b/libs/binder/Android.bp
@@ -120,7 +120,6 @@
         "ParcelFileDescriptor.cpp",
         "PersistableBundle.cpp",
         "ProcessState.cpp",
-        "RpcAddress.cpp",
         "RpcSession.cpp",
         "RpcServer.cpp",
         "RpcState.cpp",
diff --git a/libs/binder/BpBinder.cpp b/libs/binder/BpBinder.cpp
index 1100d72..687ee25 100644
--- a/libs/binder/BpBinder.cpp
+++ b/libs/binder/BpBinder.cpp
@@ -156,7 +156,7 @@
     return sp<BpBinder>::make(BinderHandle{handle}, trackedUid);
 }
 
-sp<BpBinder> BpBinder::create(const sp<RpcSession>& session, const RpcAddress& address) {
+sp<BpBinder> BpBinder::create(const sp<RpcSession>& session, uint64_t address) {
     LOG_ALWAYS_FATAL_IF(session == nullptr, "BpBinder::create null session");
 
     // These are not currently tracked, since there is no UID or other
@@ -193,7 +193,7 @@
     return std::holds_alternative<RpcHandle>(mHandle);
 }
 
-const RpcAddress& BpBinder::rpcAddress() const {
+uint64_t BpBinder::rpcAddress() const {
     return std::get<RpcHandle>(mHandle).address;
 }
 
diff --git a/libs/binder/Parcel.cpp b/libs/binder/Parcel.cpp
index b545484..9147e23 100644
--- a/libs/binder/Parcel.cpp
+++ b/libs/binder/Parcel.cpp
@@ -205,11 +205,11 @@
         if (binder) {
             status_t status = writeInt32(1); // non-null
             if (status != OK) return status;
-            RpcAddress address = RpcAddress::zero();
+            uint64_t address;
             // TODO(b/167966510): need to undo this if the Parcel is not sent
             status = mSession->state()->onBinderLeaving(mSession, binder, &address);
             if (status != OK) return status;
-            status = address.writeToParcel(this);
+            status = writeUint64(address);
             if (status != OK) return status;
         } else {
             status_t status = writeInt32(0); // null
@@ -279,15 +279,15 @@
     if (isForRpc()) {
         LOG_ALWAYS_FATAL_IF(mSession == nullptr, "RpcSession required to read from remote parcel");
 
-        int32_t isNull;
-        status_t status = readInt32(&isNull);
+        int32_t isPresent;
+        status_t status = readInt32(&isPresent);
         if (status != OK) return status;
 
         sp<IBinder> binder;
 
-        if (isNull & 1) {
-            auto addr = RpcAddress::zero();
-            if (status_t status = addr.readFromParcel(*this); status != OK) return status;
+        if (isPresent & 1) {
+            uint64_t addr;
+            if (status_t status = readUint64(&addr); status != OK) return status;
             if (status_t status = mSession->state()->onBinderEntering(mSession, addr, &binder);
                 status != OK)
                 return status;
diff --git a/libs/binder/RpcAddress.cpp b/libs/binder/RpcAddress.cpp
deleted file mode 100644
index ffc94b9..0000000
--- a/libs/binder/RpcAddress.cpp
+++ /dev/null
@@ -1,112 +0,0 @@
-/*
- * Copyright (C) 2020 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 <binder/RpcAddress.h>
-
-#include <android-base/hex.h>
-#include <binder/Parcel.h>
-
-#include "Debug.h"
-#include "RpcState.h"
-#include "RpcWireFormat.h"
-
-namespace android {
-
-RpcAddress RpcAddress::zero() {
-    return RpcAddress();
-}
-
-bool RpcAddress::isZero() const {
-    RpcWireAddress ZERO{.options = 0};
-    return memcmp(mRawAddr.get(), &ZERO, sizeof(RpcWireAddress)) == 0;
-}
-
-static void ReadRandomBytes(uint8_t* buf, size_t len) {
-    int fd = TEMP_FAILURE_RETRY(open("/dev/urandom", O_RDONLY | O_CLOEXEC | O_NOFOLLOW));
-    if (fd == -1) {
-        ALOGE("%s: cannot read /dev/urandom", __func__);
-        return;
-    }
-
-    size_t n;
-    while ((n = TEMP_FAILURE_RETRY(read(fd, buf, len))) > 0) {
-        len -= n;
-        buf += n;
-    }
-    if (len > 0) {
-        ALOGW("%s: there are %d bytes skipped", __func__, (int)len);
-    }
-    close(fd);
-}
-
-RpcAddress RpcAddress::random(bool forServer) {
-    // The remainder of this header acts as reserved space for different kinds
-    // of binder objects.
-    uint64_t options = RPC_WIRE_ADDRESS_OPTION_CREATED;
-
-    // servers and clients allocate addresses independently, so this bit can
-    // tell you where an address originates
-    if (forServer) options |= RPC_WIRE_ADDRESS_OPTION_FOR_SERVER;
-
-    RpcAddress ret;
-    RpcWireAddress* raw = ret.mRawAddr.get();
-
-    raw->options = options;
-    ReadRandomBytes(raw->address, sizeof(raw->address));
-
-    LOG_RPC_DETAIL("Creating new address: %s", ret.toString().c_str());
-    return ret;
-}
-
-bool RpcAddress::isForServer() const {
-    return mRawAddr.get()->options & RPC_WIRE_ADDRESS_OPTION_FOR_SERVER;
-}
-
-bool RpcAddress::isRecognizedType() const {
-    uint64_t allKnownOptions = RPC_WIRE_ADDRESS_OPTION_CREATED | RPC_WIRE_ADDRESS_OPTION_FOR_SERVER;
-    return (mRawAddr.get()->options & ~allKnownOptions) == 0;
-}
-
-RpcAddress RpcAddress::fromRawEmbedded(const RpcWireAddress* raw) {
-    RpcAddress addr;
-    memcpy(addr.mRawAddr.get(), raw, sizeof(RpcWireAddress));
-    return addr;
-}
-
-const RpcWireAddress& RpcAddress::viewRawEmbedded() const {
-    return *mRawAddr.get();
-}
-
-bool RpcAddress::operator<(const RpcAddress& rhs) const {
-    return std::memcmp(mRawAddr.get(), rhs.mRawAddr.get(), sizeof(RpcWireAddress)) < 0;
-}
-
-std::string RpcAddress::toString() const {
-    return base::HexString(mRawAddr.get(), sizeof(RpcWireAddress));
-}
-
-status_t RpcAddress::writeToParcel(Parcel* parcel) const {
-    return parcel->write(mRawAddr.get(), sizeof(RpcWireAddress));
-}
-
-status_t RpcAddress::readFromParcel(const Parcel& parcel) {
-    return parcel.read(mRawAddr.get(), sizeof(RpcWireAddress));
-}
-
-RpcAddress::~RpcAddress() {}
-RpcAddress::RpcAddress() : mRawAddr(std::make_shared<RpcWireAddress>()) {}
-
-} // namespace android
diff --git a/libs/binder/RpcServer.cpp b/libs/binder/RpcServer.cpp
index ba723e6..7fa2f57 100644
--- a/libs/binder/RpcServer.cpp
+++ b/libs/binder/RpcServer.cpp
@@ -23,6 +23,8 @@
 #include <thread>
 #include <vector>
 
+#include <android-base/file.h>
+#include <android-base/hex.h>
 #include <android-base/scopeguard.h>
 #include <binder/Parcel.h>
 #include <binder/RpcServer.h>
@@ -281,17 +283,29 @@
         }
     }
 
+    std::vector<uint8_t> sessionId;
+    if (status == OK) {
+        if (header.sessionIdSize > 0) {
+            sessionId.resize(header.sessionIdSize);
+            status = client->interruptableReadFully(server->mShutdownTrigger.get(),
+                                                    sessionId.data(), sessionId.size());
+            if (status != OK) {
+                ALOGE("Failed to read session ID for client connecting to RPC server: %s",
+                      statusToString(status).c_str());
+                // still need to cleanup before we can return
+            }
+        }
+    }
+
     bool incoming = false;
     uint32_t protocolVersion = 0;
-    RpcAddress sessionId = RpcAddress::zero();
     bool requestingNewSession = false;
 
     if (status == OK) {
         incoming = header.options & RPC_CONNECTION_OPTION_INCOMING;
         protocolVersion = std::min(header.version,
                                    server->mProtocolVersion.value_or(RPC_WIRE_PROTOCOL_VERSION));
-        sessionId = RpcAddress::fromRawEmbedded(&header.sessionId);
-        requestingNewSession = sessionId.isZero();
+        requestingNewSession = sessionId.empty();
 
         if (requestingNewSession) {
             RpcNewSessionResponse response{
@@ -333,15 +347,26 @@
                 return;
             }
 
+            // Uniquely identify session at the application layer. Even if a
+            // client/server use the same certificates, if they create multiple
+            // sessions, we still want to distinguish between them.
+            constexpr size_t kSessionIdSize = 32;
+            sessionId.resize(kSessionIdSize);
             size_t tries = 0;
             do {
                 // don't block if there is some entropy issue
                 if (tries++ > 5) {
-                    ALOGE("Cannot find new address: %s", sessionId.toString().c_str());
+                    ALOGE("Cannot find new address: %s",
+                          base::HexString(sessionId.data(), sessionId.size()).c_str());
                     return;
                 }
 
-                sessionId = RpcAddress::random(true /*forServer*/);
+                base::unique_fd fd(TEMP_FAILURE_RETRY(
+                        open("/dev/urandom", O_RDONLY | O_CLOEXEC | O_NOFOLLOW)));
+                if (!base::ReadFully(fd, sessionId.data(), sessionId.size())) {
+                    ALOGE("Could not read from /dev/urandom to create session ID");
+                    return;
+                }
             } while (server->mSessions.end() != server->mSessions.find(sessionId));
 
             session = RpcSession::make();
@@ -361,7 +386,7 @@
             auto it = server->mSessions.find(sessionId);
             if (it == server->mSessions.end()) {
                 ALOGE("Cannot add thread, no record of session with ID %s",
-                      sessionId.toString().c_str());
+                      base::HexString(sessionId.data(), sessionId.size()).c_str());
                 return;
             }
             session = it->second;
@@ -423,16 +448,17 @@
 }
 
 void RpcServer::onSessionAllIncomingThreadsEnded(const sp<RpcSession>& session) {
-    auto id = session->mId;
-    LOG_ALWAYS_FATAL_IF(id == std::nullopt, "Server sessions must be initialized with ID");
-    LOG_RPC_DETAIL("Dropping session with address %s", id->toString().c_str());
+    const std::vector<uint8_t>& id = session->mId;
+    LOG_ALWAYS_FATAL_IF(id.empty(), "Server sessions must be initialized with ID");
+    LOG_RPC_DETAIL("Dropping session with address %s",
+                   base::HexString(id.data(), id.size()).c_str());
 
     std::lock_guard<std::mutex> _l(mLock);
-    auto it = mSessions.find(*id);
+    auto it = mSessions.find(id);
     LOG_ALWAYS_FATAL_IF(it == mSessions.end(), "Bad state, unknown session id %s",
-                        id->toString().c_str());
+                        base::HexString(id.data(), id.size()).c_str());
     LOG_ALWAYS_FATAL_IF(it->second != session, "Bad state, session has id mismatch %s",
-                        id->toString().c_str());
+                        base::HexString(id.data(), id.size()).c_str());
     (void)mSessions.erase(it);
 }
 
diff --git a/libs/binder/RpcSession.cpp b/libs/binder/RpcSession.cpp
index 8da3fa3..c5a8dd1 100644
--- a/libs/binder/RpcSession.cpp
+++ b/libs/binder/RpcSession.cpp
@@ -26,6 +26,7 @@
 
 #include <string_view>
 
+#include <android-base/hex.h>
 #include <android-base/macros.h>
 #include <android_runtime/vm.h>
 #include <binder/Parcel.h>
@@ -132,7 +133,7 @@
 }
 
 status_t RpcSession::setupPreconnectedClient(unique_fd fd, std::function<unique_fd()>&& request) {
-    return setupClient([&](const RpcAddress& sessionId, bool incoming) -> status_t {
+    return setupClient([&](const std::vector<uint8_t>& sessionId, bool incoming) -> status_t {
         // std::move'd from fd becomes -1 (!ok())
         if (!fd.ok()) {
             fd = request();
@@ -214,7 +215,7 @@
                              sp<RpcSession>::fromExisting(this), reply, flags);
 }
 
-status_t RpcSession::sendDecStrong(const RpcAddress& address) {
+status_t RpcSession::sendDecStrong(uint64_t address) {
     ExclusiveConnection connection;
     status_t status = ExclusiveConnection::find(sp<RpcSession>::fromExisting(this),
                                                 ConnectionUse::CLIENT_REFCOUNT, &connection);
@@ -233,12 +234,11 @@
                                                 ConnectionUse::CLIENT, &connection);
     if (status != OK) return status;
 
-    mId = RpcAddress::zero();
-    status = state()->getSessionId(connection.get(), sp<RpcSession>::fromExisting(this),
-                                   &mId.value());
+    status = state()->getSessionId(connection.get(), sp<RpcSession>::fromExisting(this), &mId);
     if (status != OK) return status;
 
-    LOG_RPC_DETAIL("RpcSession %p has id %s", this, mId->toString().c_str());
+    LOG_RPC_DETAIL("RpcSession %p has id %s", this,
+                   base::HexString(mId.data(), mId.size()).c_str());
     return OK;
 }
 
@@ -397,8 +397,8 @@
     return server;
 }
 
-status_t RpcSession::setupClient(
-        const std::function<status_t(const RpcAddress& sessionId, bool incoming)>& connectAndInit) {
+status_t RpcSession::setupClient(const std::function<status_t(const std::vector<uint8_t>& sessionId,
+                                                              bool incoming)>& connectAndInit) {
     {
         std::lock_guard<std::mutex> _l(mMutex);
         LOG_ALWAYS_FATAL_IF(mOutgoingConnections.size() != 0,
@@ -407,8 +407,7 @@
     }
     if (auto status = initShutdownTrigger(); status != OK) return status;
 
-    if (status_t status = connectAndInit(RpcAddress::zero(), false /*incoming*/); status != OK)
-        return status;
+    if (status_t status = connectAndInit({}, false /*incoming*/); status != OK) return status;
 
     {
         ExclusiveConnection connection;
@@ -449,26 +448,25 @@
 
     // we've already setup one client
     for (size_t i = 0; i + 1 < numThreadsAvailable; i++) {
-        if (status_t status = connectAndInit(mId.value(), false /*incoming*/); status != OK)
-            return status;
+        if (status_t status = connectAndInit(mId, false /*incoming*/); status != OK) return status;
     }
 
     for (size_t i = 0; i < mMaxThreads; i++) {
-        if (status_t status = connectAndInit(mId.value(), true /*incoming*/); status != OK)
-            return status;
+        if (status_t status = connectAndInit(mId, true /*incoming*/); status != OK) return status;
     }
 
     return OK;
 }
 
 status_t RpcSession::setupSocketClient(const RpcSocketAddress& addr) {
-    return setupClient([&](const RpcAddress& sessionId, bool incoming) {
+    return setupClient([&](const std::vector<uint8_t>& sessionId, bool incoming) {
         return setupOneSocketConnection(addr, sessionId, incoming);
     });
 }
 
 status_t RpcSession::setupOneSocketConnection(const RpcSocketAddress& addr,
-                                              const RpcAddress& sessionId, bool incoming) {
+                                              const std::vector<uint8_t>& sessionId,
+                                              bool incoming) {
     for (size_t tries = 0; tries < 5; tries++) {
         if (tries > 0) usleep(10000);
 
@@ -526,7 +524,7 @@
     return UNKNOWN_ERROR;
 }
 
-status_t RpcSession::initAndAddConnection(unique_fd fd, const RpcAddress& sessionId,
+status_t RpcSession::initAndAddConnection(unique_fd fd, const std::vector<uint8_t>& sessionId,
                                           bool incoming) {
     LOG_ALWAYS_FATAL_IF(mShutdownTrigger == nullptr);
     auto server = mCtx->newTransport(std::move(fd), mShutdownTrigger.get());
@@ -537,13 +535,20 @@
 
     LOG_RPC_DETAIL("Socket at client with RpcTransport %p", server.get());
 
+    if (sessionId.size() > std::numeric_limits<uint16_t>::max()) {
+        ALOGE("Session ID too big %zu", sessionId.size());
+        return BAD_VALUE;
+    }
+
     RpcConnectionHeader header{
             .version = mProtocolVersion.value_or(RPC_WIRE_PROTOCOL_VERSION),
             .options = 0,
+            .sessionIdSize = static_cast<uint16_t>(sessionId.size()),
     };
-    memcpy(&header.sessionId, &sessionId.viewRawEmbedded(), sizeof(RpcWireAddress));
 
-    if (incoming) header.options |= RPC_CONNECTION_OPTION_INCOMING;
+    if (incoming) {
+        header.options |= RPC_CONNECTION_OPTION_INCOMING;
+    }
 
     auto sendHeaderStatus =
             server->interruptableWriteFully(mShutdownTrigger.get(), &header, sizeof(header));
@@ -553,6 +558,18 @@
         return sendHeaderStatus;
     }
 
+    if (sessionId.size() > 0) {
+        auto sendSessionIdStatus =
+                server->interruptableWriteFully(mShutdownTrigger.get(), sessionId.data(),
+                                                sessionId.size());
+        if (sendSessionIdStatus != OK) {
+            ALOGE("Could not write session ID ('%s') to socket: %s",
+                  base::HexString(sessionId.data(), sessionId.size()).c_str(),
+                  statusToString(sendSessionIdStatus).c_str());
+            return sendSessionIdStatus;
+        }
+    }
+
     LOG_RPC_DETAIL("Socket at client: header sent");
 
     if (incoming) {
@@ -625,7 +642,7 @@
 }
 
 bool RpcSession::setForServer(const wp<RpcServer>& server, const wp<EventListener>& eventListener,
-                              const RpcAddress& sessionId) {
+                              const std::vector<uint8_t>& sessionId) {
     LOG_ALWAYS_FATAL_IF(mForServer != nullptr);
     LOG_ALWAYS_FATAL_IF(server == nullptr);
     LOG_ALWAYS_FATAL_IF(mEventListener != nullptr);
diff --git a/libs/binder/RpcState.cpp b/libs/binder/RpcState.cpp
index b58f1b3..59643ba 100644
--- a/libs/binder/RpcState.cpp
+++ b/libs/binder/RpcState.cpp
@@ -52,7 +52,7 @@
 RpcState::~RpcState() {}
 
 status_t RpcState::onBinderLeaving(const sp<RpcSession>& session, const sp<IBinder>& binder,
-                                   RpcAddress* outAddress) {
+                                   uint64_t* outAddress) {
     bool isRemote = binder->remoteBinder();
     bool isRpc = isRemote && binder->remoteBinder()->isRpcBinder();
 
@@ -84,12 +84,11 @@
     for (auto& [addr, node] : mNodeForAddress) {
         if (binder == node.binder) {
             if (isRpc) {
-                const RpcAddress& actualAddr =
+                // check integrity of data structure
+                uint64_t actualAddr =
                         binder->remoteBinder()->getPrivateAccessorForId().rpcAddress();
-                // TODO(b/182939933): this is only checking integrity of data structure
-                // a different data structure doesn't need this
-                LOG_ALWAYS_FATAL_IF(addr < actualAddr, "Address mismatch");
-                LOG_ALWAYS_FATAL_IF(actualAddr < addr, "Address mismatch");
+                LOG_ALWAYS_FATAL_IF(addr != actualAddr, "Address mismatch %" PRIu64 " vs %" PRIu64,
+                                    addr, actualAddr);
             }
             node.timesSent++;
             node.sentRef = binder; // might already be set
@@ -101,8 +100,29 @@
 
     bool forServer = session->server() != nullptr;
 
-    for (size_t tries = 0; tries < 5; tries++) {
-        auto&& [it, inserted] = mNodeForAddress.insert({RpcAddress::random(forServer),
+    // arbitrary limit for maximum number of nodes in a process (otherwise we
+    // might run out of addresses)
+    if (mNodeForAddress.size() > 100000) {
+        return NO_MEMORY;
+    }
+
+    while (true) {
+        RpcWireAddress address{
+                .options = RPC_WIRE_ADDRESS_OPTION_CREATED,
+                .address = mNextId,
+        };
+        if (forServer) {
+            address.options |= RPC_WIRE_ADDRESS_OPTION_FOR_SERVER;
+        }
+
+        // avoid ubsan abort
+        if (mNextId >= std::numeric_limits<uint32_t>::max()) {
+            mNextId = 0;
+        } else {
+            mNextId++;
+        }
+
+        auto&& [it, inserted] = mNodeForAddress.insert({RpcWireAddress::toRaw(address),
                                                         BinderNode{
                                                                 .binder = binder,
                                                                 .timesSent = 1,
@@ -112,18 +132,10 @@
             *outAddress = it->first;
             return OK;
         }
-
-        // well, we don't have visibility into the header here, but still
-        static_assert(sizeof(RpcWireAddress) == 40, "this log needs updating");
-        ALOGW("2**256 is 1e77. If you see this log, you probably have some entropy issue, or maybe "
-              "you witness something incredible!");
     }
-
-    ALOGE("Unable to create an address in order to send out %p", binder.get());
-    return WOULD_BLOCK;
 }
 
-status_t RpcState::onBinderEntering(const sp<RpcSession>& session, const RpcAddress& address,
+status_t RpcState::onBinderEntering(const sp<RpcSession>& session, uint64_t address,
                                     sp<IBinder>* out) {
     // ensure that: if we want to use addresses for something else in the future (for
     //   instance, allowing transitive binder sends), that we don't accidentally
@@ -133,8 +145,11 @@
     //   if we communicate with a binder, it could always be proxying
     //   information. However, we want to make sure that isn't done on accident
     //   by a client.
-    if (!address.isRecognizedType()) {
-        ALOGE("Address is of an unknown type, rejecting: %s", address.toString().c_str());
+    RpcWireAddress addr = RpcWireAddress::fromRaw(address);
+    constexpr uint32_t kKnownOptions =
+            RPC_WIRE_ADDRESS_OPTION_CREATED | RPC_WIRE_ADDRESS_OPTION_FOR_SERVER;
+    if (addr.options & ~kKnownOptions) {
+        ALOGE("Address is of an unknown type, rejecting: %" PRIu64, address);
         return BAD_VALUE;
     }
 
@@ -159,9 +174,9 @@
 
     // we don't know about this binder, so the other side of the connection
     // should have created it.
-    if (address.isForServer() == !!session->server()) {
-        ALOGE("Server received unrecognized address which we should own the creation of %s.",
-              address.toString().c_str());
+    if ((addr.options & RPC_WIRE_ADDRESS_OPTION_FOR_SERVER) == !!session->server()) {
+        ALOGE("Server received unrecognized address which we should own the creation of %" PRIu64,
+              address);
         return BAD_VALUE;
     }
 
@@ -241,9 +256,8 @@
             desc = "(null)";
         }
 
-        ALOGE("- BINDER NODE: %p times sent:%zu times recd: %zu a:%s type:%s",
-              node.binder.unsafe_get(), node.timesSent, node.timesRecd, address.toString().c_str(),
-              desc);
+        ALOGE("- BINDER NODE: %p times sent:%zu times recd: %zu a: %" PRIu64 " type: %s",
+              node.binder.unsafe_get(), node.timesSent, node.timesRecd, address, desc);
     }
     ALOGE("END DUMP OF RpcState");
 }
@@ -360,8 +374,8 @@
     data.markForRpc(session);
     Parcel reply;
 
-    status_t status = transactAddress(connection, RpcAddress::zero(), RPC_SPECIAL_TRANSACT_GET_ROOT,
-                                      data, session, &reply, 0);
+    status_t status =
+            transactAddress(connection, 0, RPC_SPECIAL_TRANSACT_GET_ROOT, data, session, &reply, 0);
     if (status != OK) {
         ALOGE("Error getting root object: %s", statusToString(status).c_str());
         return nullptr;
@@ -376,9 +390,8 @@
     data.markForRpc(session);
     Parcel reply;
 
-    status_t status =
-            transactAddress(connection, RpcAddress::zero(), RPC_SPECIAL_TRANSACT_GET_MAX_THREADS,
-                            data, session, &reply, 0);
+    status_t status = transactAddress(connection, 0, RPC_SPECIAL_TRANSACT_GET_MAX_THREADS, data,
+                                      session, &reply, 0);
     if (status != OK) {
         ALOGE("Error getting max threads: %s", statusToString(status).c_str());
         return status;
@@ -397,20 +410,19 @@
 }
 
 status_t RpcState::getSessionId(const sp<RpcSession::RpcConnection>& connection,
-                                const sp<RpcSession>& session, RpcAddress* sessionIdOut) {
+                                const sp<RpcSession>& session, std::vector<uint8_t>* sessionIdOut) {
     Parcel data;
     data.markForRpc(session);
     Parcel reply;
 
-    status_t status =
-            transactAddress(connection, RpcAddress::zero(), RPC_SPECIAL_TRANSACT_GET_SESSION_ID,
-                            data, session, &reply, 0);
+    status_t status = transactAddress(connection, 0, RPC_SPECIAL_TRANSACT_GET_SESSION_ID, data,
+                                      session, &reply, 0);
     if (status != OK) {
         ALOGE("Error getting session ID: %s", statusToString(status).c_str());
         return status;
     }
 
-    return sessionIdOut->readFromParcel(reply);
+    return reply.readByteVector(sessionIdOut);
 }
 
 status_t RpcState::transact(const sp<RpcSession::RpcConnection>& connection,
@@ -426,26 +438,26 @@
         return BAD_TYPE;
     }
 
-    RpcAddress address = RpcAddress::zero();
+    uint64_t address;
     if (status_t status = onBinderLeaving(session, binder, &address); status != OK) return status;
 
     return transactAddress(connection, address, code, data, session, reply, flags);
 }
 
 status_t RpcState::transactAddress(const sp<RpcSession::RpcConnection>& connection,
-                                   const RpcAddress& address, uint32_t code, const Parcel& data,
+                                   uint64_t address, uint32_t code, const Parcel& data,
                                    const sp<RpcSession>& session, Parcel* reply, uint32_t flags) {
     LOG_ALWAYS_FATAL_IF(!data.isForRpc());
     LOG_ALWAYS_FATAL_IF(data.objectsCount() != 0);
 
     uint64_t asyncNumber = 0;
 
-    if (!address.isZero()) {
+    if (address != 0) {
         std::unique_lock<std::mutex> _l(mNodeMutex);
         if (mTerminated) return DEAD_OBJECT; // avoid fatal only, otherwise races
         auto it = mNodeForAddress.find(address);
-        LOG_ALWAYS_FATAL_IF(it == mNodeForAddress.end(), "Sending transact on unknown address %s",
-                            address.toString().c_str());
+        LOG_ALWAYS_FATAL_IF(it == mNodeForAddress.end(),
+                            "Sending transact on unknown address %" PRIu64, address);
 
         if (flags & IBinder::FLAG_ONEWAY) {
             asyncNumber = it->second.asyncNumber;
@@ -466,8 +478,9 @@
             .command = RPC_COMMAND_TRANSACT,
             .bodySize = static_cast<uint32_t>(sizeof(RpcWireTransaction) + data.dataSize()),
     };
+
     RpcWireTransaction transaction{
-            .address = address.viewRawEmbedded(),
+            .address = RpcWireAddress::fromRaw(address),
             .code = code,
             .flags = flags,
             .asyncNumber = asyncNumber,
@@ -557,15 +570,14 @@
 }
 
 status_t RpcState::sendDecStrong(const sp<RpcSession::RpcConnection>& connection,
-                                 const sp<RpcSession>& session, const RpcAddress& addr) {
+                                 const sp<RpcSession>& session, uint64_t addr) {
     {
         std::lock_guard<std::mutex> _l(mNodeMutex);
         if (mTerminated) return DEAD_OBJECT; // avoid fatal only, otherwise races
         auto it = mNodeForAddress.find(addr);
-        LOG_ALWAYS_FATAL_IF(it == mNodeForAddress.end(), "Sending dec strong on unknown address %s",
-                            addr.toString().c_str());
-        LOG_ALWAYS_FATAL_IF(it->second.timesRecd <= 0, "Bad dec strong %s",
-                            addr.toString().c_str());
+        LOG_ALWAYS_FATAL_IF(it == mNodeForAddress.end(),
+                            "Sending dec strong on unknown address %" PRIu64, addr);
+        LOG_ALWAYS_FATAL_IF(it->second.timesRecd <= 0, "Bad dec strong %" PRIu64, addr);
 
         it->second.timesRecd--;
         LOG_ALWAYS_FATAL_IF(nullptr != tryEraseNode(it),
@@ -579,8 +591,7 @@
     if (status_t status = rpcSend(connection, session, "dec ref header", &cmd, sizeof(cmd));
         status != OK)
         return status;
-    if (status_t status = rpcSend(connection, session, "dec ref body", &addr.viewRawEmbedded(),
-                                  sizeof(RpcWireAddress));
+    if (status_t status = rpcSend(connection, session, "dec ref body", &addr, sizeof(addr));
         status != OK)
         return status;
     return OK;
@@ -685,14 +696,12 @@
     }
     RpcWireTransaction* transaction = reinterpret_cast<RpcWireTransaction*>(transactionData.data());
 
-    // TODO(b/182939933): heap allocation just for lookup in mNodeForAddress,
-    // maybe add an RpcAddress 'view' if the type remains 'heavy'
-    auto addr = RpcAddress::fromRawEmbedded(&transaction->address);
+    uint64_t addr = RpcWireAddress::toRaw(transaction->address);
     bool oneway = transaction->flags & IBinder::FLAG_ONEWAY;
 
     status_t replyStatus = OK;
     sp<IBinder> target;
-    if (!addr.isZero()) {
+    if (addr != 0) {
         if (!targetRef) {
             replyStatus = onBinderEntering(session, addr, &target);
         } else {
@@ -708,21 +717,21 @@
             // (any binder which is being transacted on should be holding a
             // strong ref count), so in either case, terminating the
             // session.
-            ALOGE("While transacting, binder has been deleted at address %s. Terminating!",
-                  addr.toString().c_str());
+            ALOGE("While transacting, binder has been deleted at address %" PRIu64 ". Terminating!",
+                  addr);
             (void)session->shutdownAndWait(false);
             replyStatus = BAD_VALUE;
         } else if (target->localBinder() == nullptr) {
-            ALOGE("Unknown binder address or non-local binder, not address %s. Terminating!",
-                  addr.toString().c_str());
+            ALOGE("Unknown binder address or non-local binder, not address %" PRIu64
+                  ". Terminating!",
+                  addr);
             (void)session->shutdownAndWait(false);
             replyStatus = BAD_VALUE;
         } else if (oneway) {
             std::unique_lock<std::mutex> _l(mNodeMutex);
             auto it = mNodeForAddress.find(addr);
             if (it->second.binder.promote() != target) {
-                ALOGE("Binder became invalid during transaction. Bad client? %s",
-                      addr.toString().c_str());
+                ALOGE("Binder became invalid during transaction. Bad client? %" PRIu64, addr);
                 replyStatus = BAD_VALUE;
             } else if (transaction->asyncNumber != it->second.asyncNumber) {
                 // we need to process some other asynchronous transaction
@@ -734,8 +743,8 @@
                 });
 
                 size_t numPending = it->second.asyncTodo.size();
-                LOG_RPC_DETAIL("Enqueuing %" PRId64 " on %s (%zu pending)",
-                               transaction->asyncNumber, addr.toString().c_str(), numPending);
+                LOG_RPC_DETAIL("Enqueuing %" PRIu64 " on %" PRIu64 " (%zu pending)",
+                               transaction->asyncNumber, addr, numPending);
 
                 constexpr size_t kArbitraryOnewayCallTerminateLevel = 10000;
                 constexpr size_t kArbitraryOnewayCallWarnLevel = 1000;
@@ -792,7 +801,7 @@
                     // for client connections, this should always report the value
                     // originally returned from the server, so this is asserting
                     // that it exists
-                    replyStatus = session->mId.value().writeToParcel(&reply);
+                    replyStatus = reply.writeByteVector(session->mId);
                     break;
                 }
                 default: {
@@ -820,8 +829,8 @@
             ALOGW("Oneway call failed with error: %d", replyStatus);
         }
 
-        LOG_RPC_DETAIL("Processed async transaction %" PRId64 " on %s", transaction->asyncNumber,
-                       addr.toString().c_str());
+        LOG_RPC_DETAIL("Processed async transaction %" PRIu64 " on %" PRIu64,
+                       transaction->asyncNumber, addr);
 
         // Check to see if there is another asynchronous transaction to process.
         // This behavior differs from binder behavior, since in the binder
@@ -847,8 +856,8 @@
 
             if (it->second.asyncTodo.size() == 0) return OK;
             if (it->second.asyncTodo.top().asyncNumber == it->second.asyncNumber) {
-                LOG_RPC_DETAIL("Found next async transaction %" PRId64 " on %s",
-                               it->second.asyncNumber, addr.toString().c_str());
+                LOG_RPC_DETAIL("Found next async transaction %" PRIu64 " on %" PRIu64,
+                               it->second.asyncNumber, addr);
 
                 // justification for const_cast (consider avoiding priority_queue):
                 // - AsyncTodo operator< doesn't depend on 'data' or 'ref' objects
@@ -904,7 +913,7 @@
         status != OK)
         return status;
 
-    if (command.bodySize < sizeof(RpcWireAddress)) {
+    if (command.bodySize != sizeof(RpcWireAddress)) {
         ALOGE("Expecting %zu but got %" PRId32 " bytes for RpcWireAddress. Terminating!",
               sizeof(RpcWireAddress), command.bodySize);
         (void)session->shutdownAndWait(false);
@@ -912,31 +921,32 @@
     }
     RpcWireAddress* address = reinterpret_cast<RpcWireAddress*>(commandData.data());
 
-    // TODO(b/182939933): heap allocation just for lookup
-    auto addr = RpcAddress::fromRawEmbedded(address);
+    uint64_t addr = RpcWireAddress::toRaw(*address);
+
     std::unique_lock<std::mutex> _l(mNodeMutex);
     auto it = mNodeForAddress.find(addr);
     if (it == mNodeForAddress.end()) {
-        ALOGE("Unknown binder address %s for dec strong.", addr.toString().c_str());
+        ALOGE("Unknown binder address %" PRIu64 " for dec strong.", addr);
         return OK;
     }
 
     sp<IBinder> target = it->second.binder.promote();
     if (target == nullptr) {
-        ALOGE("While requesting dec strong, binder has been deleted at address %s. Terminating!",
-              addr.toString().c_str());
+        ALOGE("While requesting dec strong, binder has been deleted at address %" PRIu64
+              ". Terminating!",
+              addr);
         _l.unlock();
         (void)session->shutdownAndWait(false);
         return BAD_VALUE;
     }
 
     if (it->second.timesSent == 0) {
-        ALOGE("No record of sending binder, but requested decStrong: %s", addr.toString().c_str());
+        ALOGE("No record of sending binder, but requested decStrong: %" PRIu64, addr);
         return OK;
     }
 
-    LOG_ALWAYS_FATAL_IF(it->second.sentRef == nullptr, "Inconsistent state, lost ref for %s",
-                        addr.toString().c_str());
+    LOG_ALWAYS_FATAL_IF(it->second.sentRef == nullptr, "Inconsistent state, lost ref for %" PRIu64,
+                        addr);
 
     it->second.timesSent--;
     sp<IBinder> tempHold = tryEraseNode(it);
@@ -946,7 +956,7 @@
     return OK;
 }
 
-sp<IBinder> RpcState::tryEraseNode(std::map<RpcAddress, BinderNode>::iterator& it) {
+sp<IBinder> RpcState::tryEraseNode(std::map<uint64_t, BinderNode>::iterator& it) {
     sp<IBinder> ref;
 
     if (it->second.timesSent == 0) {
diff --git a/libs/binder/RpcState.h b/libs/binder/RpcState.h
index 1446eec..dcfb569 100644
--- a/libs/binder/RpcState.h
+++ b/libs/binder/RpcState.h
@@ -73,17 +73,17 @@
     status_t getMaxThreads(const sp<RpcSession::RpcConnection>& connection,
                            const sp<RpcSession>& session, size_t* maxThreadsOut);
     status_t getSessionId(const sp<RpcSession::RpcConnection>& connection,
-                          const sp<RpcSession>& session, RpcAddress* sessionIdOut);
+                          const sp<RpcSession>& session, std::vector<uint8_t>* sessionIdOut);
 
     [[nodiscard]] status_t transact(const sp<RpcSession::RpcConnection>& connection,
                                     const sp<IBinder>& address, uint32_t code, const Parcel& data,
                                     const sp<RpcSession>& session, Parcel* reply, uint32_t flags);
     [[nodiscard]] status_t transactAddress(const sp<RpcSession::RpcConnection>& connection,
-                                           const RpcAddress& address, uint32_t code,
-                                           const Parcel& data, const sp<RpcSession>& session,
-                                           Parcel* reply, uint32_t flags);
+                                           uint64_t address, uint32_t code, const Parcel& data,
+                                           const sp<RpcSession>& session, Parcel* reply,
+                                           uint32_t flags);
     [[nodiscard]] status_t sendDecStrong(const sp<RpcSession::RpcConnection>& connection,
-                                         const sp<RpcSession>& session, const RpcAddress& address);
+                                         const sp<RpcSession>& session, uint64_t address);
 
     enum class CommandType {
         ANY,
@@ -99,15 +99,15 @@
      * ownership to the outgoing binder.
      */
     [[nodiscard]] status_t onBinderLeaving(const sp<RpcSession>& session, const sp<IBinder>& binder,
-                                           RpcAddress* outAddress);
+                                           uint64_t* outAddress);
 
     /**
      * Called by Parcel for incoming binders. This either returns the refcount
      * to the process, if this process already has one, or it takes ownership of
      * that refcount
      */
-    [[nodiscard]] status_t onBinderEntering(const sp<RpcSession>& session,
-                                            const RpcAddress& address, sp<IBinder>* out);
+    [[nodiscard]] status_t onBinderEntering(const sp<RpcSession>& session, uint64_t address,
+                                            sp<IBinder>* out);
 
     size_t countBinders();
     void dump();
@@ -221,15 +221,16 @@
     // happens, and there is a strong reference to the binder kept by
     // binderNode, this returns that strong reference, so that it can be
     // dropped after any locks are removed.
-    sp<IBinder> tryEraseNode(std::map<RpcAddress, BinderNode>::iterator& it);
+    sp<IBinder> tryEraseNode(std::map<uint64_t, BinderNode>::iterator& it);
     // true - success
     // false - session shutdown, halt
     [[nodiscard]] bool nodeProgressAsyncNumber(BinderNode* node);
 
     std::mutex mNodeMutex;
     bool mTerminated = false;
+    uint32_t mNextId = 0;
     // binders known by both sides of a session
-    std::map<RpcAddress, BinderNode> mNodeForAddress;
+    std::map<uint64_t, BinderNode> mNodeForAddress;
 };
 
 } // namespace android
diff --git a/libs/binder/RpcWireFormat.h b/libs/binder/RpcWireFormat.h
index 067c4ad..a87aa07 100644
--- a/libs/binder/RpcWireFormat.h
+++ b/libs/binder/RpcWireFormat.h
@@ -20,18 +20,23 @@
 #pragma clang diagnostic push
 #pragma clang diagnostic error "-Wpadded"
 
-enum : uint8_t {
-    RPC_CONNECTION_OPTION_INCOMING = 0x1, // default is outgoing
-};
+constexpr uint8_t RPC_CONNECTION_OPTION_INCOMING = 0x1; // default is outgoing
 
-constexpr uint64_t RPC_WIRE_ADDRESS_OPTION_CREATED = 1 << 0; // distinguish from '0' address
-constexpr uint64_t RPC_WIRE_ADDRESS_OPTION_FOR_SERVER = 1 << 1;
+constexpr uint32_t RPC_WIRE_ADDRESS_OPTION_CREATED = 1 << 0; // distinguish from '0' address
+constexpr uint32_t RPC_WIRE_ADDRESS_OPTION_FOR_SERVER = 1 << 1;
 
 struct RpcWireAddress {
-    uint64_t options;
-    uint8_t address[32];
+    uint32_t options;
+    uint32_t address;
+
+    static inline RpcWireAddress fromRaw(uint64_t raw) {
+        return *reinterpret_cast<RpcWireAddress*>(&raw);
+    }
+    static inline uint64_t toRaw(RpcWireAddress addr) {
+        return *reinterpret_cast<uint64_t*>(&addr);
+    }
 };
-static_assert(sizeof(RpcWireAddress) == 40);
+static_assert(sizeof(RpcWireAddress) == sizeof(uint64_t));
 
 /**
  * This is sent to an RpcServer in order to request a new connection is created,
@@ -39,12 +44,13 @@
  */
 struct RpcConnectionHeader {
     uint32_t version; // maximum supported by caller
-    uint8_t reserver0[4];
-    RpcWireAddress sessionId;
     uint8_t options;
-    uint8_t reserved1[7];
+    uint8_t reservered[9];
+    // Follows is sessionIdSize bytes.
+    // if size is 0, this is requesting a new session.
+    uint16_t sessionIdSize;
 };
-static_assert(sizeof(RpcConnectionHeader) == 56);
+static_assert(sizeof(RpcConnectionHeader) == 16);
 
 /**
  * In response to an RpcConnectionHeader which corresponds to a new session,
@@ -122,7 +128,7 @@
 
     uint8_t data[];
 };
-static_assert(sizeof(RpcWireTransaction) == 72);
+static_assert(sizeof(RpcWireTransaction) == 40);
 
 struct RpcWireReply {
     int32_t status; // transact return
diff --git a/libs/binder/include/binder/BpBinder.h b/libs/binder/include/binder/BpBinder.h
index b58cb7e..9f2ce1e 100644
--- a/libs/binder/include/binder/BpBinder.h
+++ b/libs/binder/include/binder/BpBinder.h
@@ -17,7 +17,6 @@
 #pragma once
 
 #include <binder/IBinder.h>
-#include <binder/RpcAddress.h>
 #include <utils/KeyedVector.h>
 #include <utils/Mutex.h>
 #include <utils/threads.h>
@@ -41,7 +40,7 @@
 {
 public:
     static sp<BpBinder> create(int32_t handle);
-    static sp<BpBinder> create(const sp<RpcSession>& session, const RpcAddress& address);
+    static sp<BpBinder> create(const sp<RpcSession>& session, uint64_t address);
 
     /**
      * Return value:
@@ -129,7 +128,7 @@
         int32_t binderHandle() const { return mBinder->binderHandle(); }
 
         // valid if isRpcBinder
-        const RpcAddress& rpcAddress() const { return mBinder->rpcAddress(); }
+        uint64_t rpcAddress() const { return mBinder->rpcAddress(); }
         const sp<RpcSession>& rpcSession() const { return mBinder->rpcSession(); }
 
         const BpBinder* mBinder;
@@ -147,12 +146,12 @@
     };
     struct RpcHandle {
         sp<RpcSession> session;
-        RpcAddress address;
+        uint64_t address;
     };
     using Handle = std::variant<BinderHandle, RpcHandle>;
 
     int32_t binderHandle() const;
-    const RpcAddress& rpcAddress() const;
+    uint64_t rpcAddress() const;
     const sp<RpcSession>& rpcSession() const;
 
     explicit BpBinder(Handle&& handle);
diff --git a/libs/binder/include/binder/RpcAddress.h b/libs/binder/include/binder/RpcAddress.h
deleted file mode 100644
index e428908..0000000
--- a/libs/binder/include/binder/RpcAddress.h
+++ /dev/null
@@ -1,80 +0,0 @@
-/*
- * Copyright (C) 2020 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.
- */
-#pragma once
-
-#include <memory>
-
-#include <utils/Errors.h>
-
-// WARNING: This is a feature which is still in development, and it is subject
-// to radical change. Any production use of this may subject your code to any
-// number of problems.
-
-namespace android {
-
-class Parcel;
-struct RpcWireAddress;
-
-/**
- * This class represents an identifier across an RPC boundary.
- */
-class RpcAddress {
-public:
-    /**
-     * The zero address is used for special RPC transactions, but it might also
-     * be used in conjunction with readFromParcel.
-     */
-    static RpcAddress zero();
-
-    bool isZero() const;
-
-    /**
-     * Create a new random address.
-     */
-    static RpcAddress random(bool forServer);
-
-    /**
-     * Whether this address was created with 'bool forServer' true
-     */
-    bool isForServer() const;
-
-    /**
-     * Whether this address is one that could be created with this version of
-     * libbinder.
-     */
-    bool isRecognizedType() const;
-
-    /**
-     * Creates a new address as a copy of an embedded object.
-     */
-    static RpcAddress fromRawEmbedded(const RpcWireAddress* raw);
-    const RpcWireAddress& viewRawEmbedded() const;
-
-    bool operator<(const RpcAddress& rhs) const;
-    std::string toString() const;
-
-    status_t writeToParcel(Parcel* parcel) const;
-    status_t readFromParcel(const Parcel& parcel);
-
-    ~RpcAddress();
-
-private:
-    RpcAddress();
-
-    std::shared_ptr<RpcWireAddress> mRawAddr;
-};
-
-} // namespace android
diff --git a/libs/binder/include/binder/RpcServer.h b/libs/binder/include/binder/RpcServer.h
index da1f79b..5229cfe 100644
--- a/libs/binder/include/binder/RpcServer.h
+++ b/libs/binder/include/binder/RpcServer.h
@@ -17,7 +17,6 @@
 
 #include <android-base/unique_fd.h>
 #include <binder/IBinder.h>
-#include <binder/RpcAddress.h>
 #include <binder/RpcSession.h>
 #include <binder/RpcTransport.h>
 #include <utils/Errors.h>
@@ -195,7 +194,7 @@
     std::map<std::thread::id, std::thread> mConnectingThreads;
     sp<IBinder> mRootObject;
     wp<IBinder> mRootObjectWeak;
-    std::map<RpcAddress, sp<RpcSession>> mSessions;
+    std::map<std::vector<uint8_t>, sp<RpcSession>> mSessions;
     std::unique_ptr<FdTrigger> mShutdownTrigger;
     std::condition_variable mShutdownCv;
 };
diff --git a/libs/binder/include/binder/RpcSession.h b/libs/binder/include/binder/RpcSession.h
index a40116f..91db637 100644
--- a/libs/binder/include/binder/RpcSession.h
+++ b/libs/binder/include/binder/RpcSession.h
@@ -17,7 +17,6 @@
 
 #include <android-base/unique_fd.h>
 #include <binder/IBinder.h>
-#include <binder/RpcAddress.h>
 #include <binder/RpcTransport.h>
 #include <utils/Errors.h>
 #include <utils/RefBase.h>
@@ -152,7 +151,7 @@
 
     [[nodiscard]] status_t transact(const sp<IBinder>& binder, uint32_t code, const Parcel& data,
                                     Parcel* reply, uint32_t flags);
-    [[nodiscard]] status_t sendDecStrong(const RpcAddress& address);
+    [[nodiscard]] status_t sendDecStrong(uint64_t address);
 
     ~RpcSession();
 
@@ -220,19 +219,21 @@
     static void join(sp<RpcSession>&& session, PreJoinSetupResult&& result);
 
     [[nodiscard]] status_t setupClient(
-            const std::function<status_t(const RpcAddress& sessionId, bool incoming)>&
+            const std::function<status_t(const std::vector<uint8_t>& sessionId, bool incoming)>&
                     connectAndInit);
     [[nodiscard]] status_t setupSocketClient(const RpcSocketAddress& address);
     [[nodiscard]] status_t setupOneSocketConnection(const RpcSocketAddress& address,
-                                                    const RpcAddress& sessionId, bool incoming);
-    [[nodiscard]] status_t initAndAddConnection(base::unique_fd fd, const RpcAddress& sessionId,
+                                                    const std::vector<uint8_t>& sessionId,
+                                                    bool incoming);
+    [[nodiscard]] status_t initAndAddConnection(base::unique_fd fd,
+                                                const std::vector<uint8_t>& sessionId,
                                                 bool incoming);
     [[nodiscard]] status_t addIncomingConnection(std::unique_ptr<RpcTransport> rpcTransport);
     [[nodiscard]] status_t addOutgoingConnection(std::unique_ptr<RpcTransport> rpcTransport,
                                                  bool init);
     [[nodiscard]] bool setForServer(const wp<RpcServer>& server,
                                     const wp<RpcSession::EventListener>& eventListener,
-                                    const RpcAddress& sessionId);
+                                    const std::vector<uint8_t>& sessionId);
     sp<RpcConnection> assignIncomingConnectionToThisThread(
             std::unique_ptr<RpcTransport> rpcTransport);
     [[nodiscard]] bool removeIncomingConnection(const sp<RpcConnection>& connection);
@@ -289,7 +290,7 @@
     sp<WaitForShutdownListener> mShutdownListener; // used for client sessions
     wp<EventListener> mEventListener; // mForServer if server, mShutdownListener if client
 
-    std::optional<RpcAddress> mId;
+    std::vector<uint8_t> mId;
 
     std::unique_ptr<FdTrigger> mShutdownTrigger;