diff --git a/libs/binder/RpcState.cpp b/libs/binder/RpcState.cpp
new file mode 100644
index 0000000..64e842e
--- /dev/null
+++ b/libs/binder/RpcState.cpp
@@ -0,0 +1,663 @@
+/*
+ * 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.
+ */
+
+#define LOG_TAG "RpcState"
+
+#include "RpcState.h"
+
+#include <binder/BpBinder.h>
+#include <binder/RpcServer.h>
+
+#include "Debug.h"
+#include "RpcWireFormat.h"
+
+#include <inttypes.h>
+
+namespace android {
+
+RpcState::RpcState() {}
+RpcState::~RpcState() {}
+
+status_t RpcState::onBinderLeaving(const sp<RpcConnection>& connection, const sp<IBinder>& binder,
+                                   RpcAddress* outAddress) {
+    bool isRemote = binder->remoteBinder();
+    bool isRpc = isRemote && binder->remoteBinder()->isRpcBinder();
+
+    if (isRpc && binder->remoteBinder()->getPrivateAccessorForId().rpcConnection() != connection) {
+        // We need to be able to send instructions over the socket for how to
+        // connect to a different server, and we also need to let the host
+        // process know that this is happening.
+        ALOGE("Canot send binder from unrelated binder RPC connection.");
+        return INVALID_OPERATION;
+    }
+
+    if (isRemote && !isRpc) {
+        // Without additional work, this would have the effect of using this
+        // process to proxy calls from the socket over to the other process, and
+        // it would make those calls look like they come from us (not over the
+        // sockets). In order to make this work transparently like binder, we
+        // would instead need to send instructions over the socket for how to
+        // connect to the host process, and we also need to let the host process
+        // know this was happening.
+        ALOGE("Cannot send binder proxy %p over sockets", binder.get());
+        return INVALID_OPERATION;
+    }
+
+    std::lock_guard<std::mutex> _l(mNodeMutex);
+
+    // TODO(b/182939933): maybe move address out of BpBinder, and keep binder->address map
+    // in RpcState
+    for (auto& [addr, node] : mNodeForAddress) {
+        if (binder == node.binder) {
+            if (isRpc) {
+                const RpcAddress& 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");
+            }
+            node.timesSent++;
+            node.sentRef = binder; // might already be set
+            *outAddress = addr;
+            return OK;
+        }
+    }
+    LOG_ALWAYS_FATAL_IF(isRpc, "RPC binder must have known address at this point");
+
+    auto&& [it, inserted] = mNodeForAddress.insert({RpcAddress::unique(),
+                                                    BinderNode{
+                                                            .binder = binder,
+                                                            .timesSent = 1,
+                                                            .sentRef = binder,
+                                                    }});
+    // TODO(b/182939933): better organization could avoid needing this log
+    LOG_ALWAYS_FATAL_IF(!inserted);
+
+    *outAddress = it->first;
+    return OK;
+}
+
+sp<IBinder> RpcState::onBinderEntering(const sp<RpcConnection>& connection,
+                                       const RpcAddress& address) {
+    std::unique_lock<std::mutex> _l(mNodeMutex);
+
+    if (auto it = mNodeForAddress.find(address); it != mNodeForAddress.end()) {
+        sp<IBinder> binder = it->second.binder.promote();
+
+        // implicitly have strong RPC refcount, since we received this binder
+        it->second.timesRecd++;
+
+        _l.unlock();
+
+        // We have timesRecd RPC refcounts, but we only need to hold on to one
+        // when we keep the object. All additional dec strongs are sent
+        // immediately, we wait to send the last one in BpBinder::onLastDecStrong.
+        (void)connection->sendDecStrong(address);
+
+        return binder;
+    }
+
+    auto&& [it, inserted] = mNodeForAddress.insert({address, BinderNode{}});
+    LOG_ALWAYS_FATAL_IF(!inserted, "Failed to insert binder when creating proxy");
+
+    // Currently, all binders are assumed to be part of the same connection (no
+    // device global binders in the RPC world).
+    sp<IBinder> binder = BpBinder::create(connection, it->first);
+    it->second.binder = binder;
+    it->second.timesRecd = 1;
+    return binder;
+}
+
+size_t RpcState::countBinders() {
+    std::lock_guard<std::mutex> _l(mNodeMutex);
+    return mNodeForAddress.size();
+}
+
+void RpcState::dump() {
+    std::lock_guard<std::mutex> _l(mNodeMutex);
+    ALOGE("DUMP OF RpcState %p", this);
+    ALOGE("DUMP OF RpcState (%zu nodes)", mNodeForAddress.size());
+    for (const auto& [address, node] : mNodeForAddress) {
+        sp<IBinder> binder = node.binder.promote();
+
+        const char* desc;
+        if (binder) {
+            if (binder->remoteBinder()) {
+                if (binder->remoteBinder()->isRpcBinder()) {
+                    desc = "(rpc binder proxy)";
+                } else {
+                    desc = "(binder proxy)";
+                }
+            } else {
+                desc = "(local binder)";
+            }
+        } else {
+            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("END DUMP OF RpcState");
+}
+
+void RpcState::terminate() {
+    if (SHOULD_LOG_RPC_DETAIL) {
+        ALOGE("RpcState::terminate()");
+        dump();
+    }
+
+    // if the destructor of a binder object makes another RPC call, then calling
+    // decStrong could deadlock. So, we must hold onto these binders until
+    // mNodeMutex is no longer taken.
+    std::vector<sp<IBinder>> tempHoldBinder;
+
+    {
+        std::lock_guard<std::mutex> _l(mNodeMutex);
+        mTerminated = true;
+        for (auto& [address, node] : mNodeForAddress) {
+            sp<IBinder> binder = node.binder.promote();
+            LOG_ALWAYS_FATAL_IF(binder == nullptr, "Binder %p expected to be owned.", binder.get());
+
+            if (node.sentRef != nullptr) {
+                tempHoldBinder.push_back(node.sentRef);
+            }
+        }
+
+        mNodeForAddress.clear();
+    }
+}
+
+bool RpcState::rpcSend(const base::unique_fd& fd, const char* what, const void* data, size_t size) {
+    LOG_RPC_DETAIL("Sending %s on fd %d: %s", what, fd.get(), hexString(data, size).c_str());
+
+    if (size > std::numeric_limits<ssize_t>::max()) {
+        ALOGE("Cannot send %s at size %zu (too big)", what, size);
+        terminate();
+        return false;
+    }
+
+    ssize_t sent = TEMP_FAILURE_RETRY(send(fd.get(), data, size, 0));
+
+    if (sent < 0 || sent != static_cast<ssize_t>(size)) {
+        ALOGE("Failed to send %s (sent %zd of %zu bytes) on fd %d, error: %s", what, sent, size,
+              fd.get(), strerror(errno));
+
+        terminate();
+        return false;
+    }
+
+    return true;
+}
+
+bool RpcState::rpcRec(const base::unique_fd& fd, const char* what, void* data, size_t size) {
+    if (size > std::numeric_limits<ssize_t>::max()) {
+        ALOGE("Cannot rec %s at size %zu (too big)", what, size);
+        terminate();
+        return false;
+    }
+
+    ssize_t recd = TEMP_FAILURE_RETRY(recv(fd.get(), data, size, MSG_WAITALL));
+
+    if (recd < 0 || recd != static_cast<ssize_t>(size)) {
+        terminate();
+
+        if (recd == 0 && errno == 0) {
+            LOG_RPC_DETAIL("No more data when trying to read %s on fd %d", what, fd.get());
+            return false;
+        }
+
+        ALOGE("Failed to read %s (received %zd of %zu bytes) on fd %d, error: %s", what, recd, size,
+              fd.get(), strerror(errno));
+        return false;
+    } else {
+        LOG_RPC_DETAIL("Received %s on fd %d: %s", what, fd.get(), hexString(data, size).c_str());
+    }
+
+    return true;
+}
+
+sp<IBinder> RpcState::getRootObject(const base::unique_fd& fd,
+                                    const sp<RpcConnection>& connection) {
+    Parcel data;
+    data.markForRpc(connection);
+    Parcel reply;
+
+    status_t status = transact(fd, RpcAddress::zero(), RPC_SPECIAL_TRANSACT_GET_ROOT, data,
+                               connection, &reply, 0);
+    if (status != OK) {
+        ALOGE("Error getting root object: %s", statusToString(status).c_str());
+        return nullptr;
+    }
+
+    return reply.readStrongBinder();
+}
+
+status_t RpcState::transact(const base::unique_fd& fd, const RpcAddress& address, uint32_t code,
+                            const Parcel& data, const sp<RpcConnection>& connection, Parcel* reply,
+                            uint32_t flags) {
+    uint64_t asyncNumber = 0;
+
+    if (!address.isZero()) {
+        std::lock_guard<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());
+
+        if (flags & IBinder::FLAG_ONEWAY) {
+            asyncNumber = it->second.asyncNumber++;
+        }
+    }
+
+    if (!data.isForRpc()) {
+        ALOGE("Refusing to send RPC with parcel not crafted for RPC");
+        return BAD_TYPE;
+    }
+
+    if (data.objectsCount() != 0) {
+        ALOGE("Parcel at %p has attached objects but is being used in an RPC call", &data);
+        return BAD_TYPE;
+    }
+
+    RpcWireTransaction transaction{
+            .address = address.viewRawEmbedded(),
+            .code = code,
+            .flags = flags,
+            .asyncNumber = asyncNumber,
+    };
+
+    std::vector<uint8_t> transactionData(sizeof(RpcWireTransaction) + data.dataSize());
+    memcpy(transactionData.data() + 0, &transaction, sizeof(RpcWireTransaction));
+    memcpy(transactionData.data() + sizeof(RpcWireTransaction), data.data(), data.dataSize());
+
+    if (transactionData.size() > std::numeric_limits<uint32_t>::max()) {
+        ALOGE("Transaction size too big %zu", transactionData.size());
+        return BAD_VALUE;
+    }
+
+    RpcWireHeader command{
+            .command = RPC_COMMAND_TRANSACT,
+            .bodySize = static_cast<uint32_t>(transactionData.size()),
+    };
+
+    if (!rpcSend(fd, "transact header", &command, sizeof(command))) {
+        return DEAD_OBJECT;
+    }
+    if (!rpcSend(fd, "command body", transactionData.data(), transactionData.size())) {
+        return DEAD_OBJECT;
+    }
+
+    if (flags & IBinder::FLAG_ONEWAY) {
+        return OK; // do not wait for result
+    }
+
+    LOG_ALWAYS_FATAL_IF(reply == nullptr, "Reply parcel must be used for synchronous transaction.");
+
+    return waitForReply(fd, connection, reply);
+}
+
+static void cleanup_data(Parcel* p, const uint8_t* data, size_t dataSize,
+                         const binder_size_t* objects, size_t objectsCount) {
+    (void)p;
+    delete[] const_cast<uint8_t*>(data - offsetof(RpcWireReply, data));
+    (void)dataSize;
+    LOG_ALWAYS_FATAL_IF(objects != nullptr);
+    LOG_ALWAYS_FATAL_IF(objectsCount, 0);
+}
+
+status_t RpcState::waitForReply(const base::unique_fd& fd, const sp<RpcConnection>& connection,
+                                Parcel* reply) {
+    RpcWireHeader command;
+    while (true) {
+        if (!rpcRec(fd, "command header", &command, sizeof(command))) {
+            return DEAD_OBJECT;
+        }
+
+        if (command.command == RPC_COMMAND_REPLY) break;
+
+        status_t status = processServerCommand(fd, connection, command);
+        if (status != OK) return status;
+    }
+
+    uint8_t* data = new uint8_t[command.bodySize];
+
+    if (!rpcRec(fd, "reply body", data, command.bodySize)) {
+        return DEAD_OBJECT;
+    }
+
+    if (command.bodySize < sizeof(RpcWireReply)) {
+        ALOGE("Expecting %zu but got %" PRId32 " bytes for RpcWireReply. Terminating!",
+              sizeof(RpcWireReply), command.bodySize);
+        terminate();
+        return BAD_VALUE;
+    }
+    RpcWireReply* rpcReply = reinterpret_cast<RpcWireReply*>(data);
+    if (rpcReply->status != OK) return rpcReply->status;
+
+    reply->ipcSetDataReference(rpcReply->data, command.bodySize - offsetof(RpcWireReply, data),
+                               nullptr, 0, cleanup_data);
+
+    reply->markForRpc(connection);
+
+    return OK;
+}
+
+status_t RpcState::sendDecStrong(const base::unique_fd& fd, const RpcAddress& 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());
+
+        it->second.timesRecd--;
+        if (it->second.timesRecd == 0 && it->second.timesSent == 0) {
+            mNodeForAddress.erase(it);
+        }
+    }
+
+    RpcWireHeader cmd = {
+            .command = RPC_COMMAND_DEC_STRONG,
+            .bodySize = sizeof(RpcWireAddress),
+    };
+    if (!rpcSend(fd, "dec ref header", &cmd, sizeof(cmd))) return DEAD_OBJECT;
+    if (!rpcSend(fd, "dec ref body", &addr.viewRawEmbedded(), sizeof(RpcWireAddress)))
+        return DEAD_OBJECT;
+    return OK;
+}
+
+status_t RpcState::getAndExecuteCommand(const base::unique_fd& fd,
+                                        const sp<RpcConnection>& connection) {
+    LOG_RPC_DETAIL("getAndExecuteCommand on fd %d", fd.get());
+
+    RpcWireHeader command;
+    if (!rpcRec(fd, "command header", &command, sizeof(command))) {
+        return DEAD_OBJECT;
+    }
+
+    return processServerCommand(fd, connection, command);
+}
+
+status_t RpcState::processServerCommand(const base::unique_fd& fd,
+                                        const sp<RpcConnection>& connection,
+                                        const RpcWireHeader& command) {
+    switch (command.command) {
+        case RPC_COMMAND_TRANSACT:
+            return processTransact(fd, connection, command);
+        case RPC_COMMAND_DEC_STRONG:
+            return processDecStrong(fd, command);
+    }
+
+    // We should always know the version of the opposing side, and since the
+    // RPC-binder-level wire protocol is not self synchronizing, we have no way
+    // to understand where the current command ends and the next one begins. We
+    // also can't consider it a fatal error because this would allow any client
+    // to kill us, so ending the connection for misbehaving client.
+    ALOGE("Unknown RPC command %d - terminating connection", command.command);
+    terminate();
+    return DEAD_OBJECT;
+}
+status_t RpcState::processTransact(const base::unique_fd& fd, const sp<RpcConnection>& connection,
+                                   const RpcWireHeader& command) {
+    LOG_ALWAYS_FATAL_IF(command.command != RPC_COMMAND_TRANSACT, "command: %d", command.command);
+
+    std::vector<uint8_t> transactionData(command.bodySize);
+    if (!rpcRec(fd, "transaction body", transactionData.data(), transactionData.size())) {
+        return DEAD_OBJECT;
+    }
+
+    return processTransactInternal(fd, connection, std::move(transactionData));
+}
+
+status_t RpcState::processTransactInternal(const base::unique_fd& fd,
+                                           const sp<RpcConnection>& connection,
+                                           std::vector<uint8_t>&& transactionData) {
+    if (transactionData.size() < sizeof(RpcWireTransaction)) {
+        ALOGE("Expecting %zu but got %zu bytes for RpcWireTransaction. Terminating!",
+              sizeof(RpcWireTransaction), transactionData.size());
+        terminate();
+        return BAD_VALUE;
+    }
+    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);
+
+    status_t replyStatus = OK;
+    sp<IBinder> target;
+    if (!addr.isZero()) {
+        std::lock_guard<std::mutex> _l(mNodeMutex);
+
+        auto it = mNodeForAddress.find(addr);
+        if (it == mNodeForAddress.end()) {
+            ALOGE("Unknown binder address %s.", addr.toString().c_str());
+            dump();
+            replyStatus = BAD_VALUE;
+        } else {
+            target = it->second.binder.promote();
+            if (target == nullptr) {
+                // This can happen if the binder is remote in this process, and
+                // another thread has called the last decStrong on this binder.
+                // However, for local binders, it indicates a misbehaving client
+                // (any binder which is being transacted on should be holding a
+                // strong ref count), so in either case, terminating the
+                // connection.
+                ALOGE("While transacting, binder has been deleted at address %s. Terminating!",
+                      addr.toString().c_str());
+                terminate();
+                replyStatus = BAD_VALUE;
+            } else if (target->localBinder() == nullptr) {
+                ALOGE("Transactions can only go to local binders, not address %s. Terminating!",
+                      addr.toString().c_str());
+                terminate();
+                replyStatus = BAD_VALUE;
+            } else if (transaction->flags & IBinder::FLAG_ONEWAY) {
+                if (transaction->asyncNumber != it->second.asyncNumber) {
+                    // we need to process some other asynchronous transaction
+                    // first
+                    // TODO(b/183140903): limit enqueues/detect overfill for bad client
+                    // TODO(b/183140903): detect when an object is deleted when it still has
+                    //        pending async transactions
+                    it->second.asyncTodo.push(BinderNode::AsyncTodo{
+                            .data = std::move(transactionData),
+                            .asyncNumber = transaction->asyncNumber,
+                    });
+                    LOG_RPC_DETAIL("Enqueuing %" PRId64 " on %s", transaction->asyncNumber,
+                                   addr.toString().c_str());
+                    return OK;
+                }
+            }
+        }
+    }
+
+    Parcel data;
+    data.setData(transaction->data, transactionData.size() - offsetof(RpcWireTransaction, data));
+    data.markForRpc(connection);
+
+    Parcel reply;
+    reply.markForRpc(connection);
+
+    if (replyStatus == OK) {
+        if (target) {
+            replyStatus = target->transact(transaction->code, data, &reply, transaction->flags);
+        } else {
+            LOG_RPC_DETAIL("Got special transaction %u", transaction->code);
+            // special case for 'zero' address (special server commands)
+            switch (transaction->code) {
+                case RPC_SPECIAL_TRANSACT_GET_ROOT: {
+                    sp<IBinder> root;
+                    sp<RpcServer> server = connection->server().promote();
+                    if (server) {
+                        root = server->getRootObject();
+                    } else {
+                        ALOGE("Root object requested, but no server attached.");
+                    }
+
+                    replyStatus = reply.writeStrongBinder(root);
+                    break;
+                }
+                default: {
+                    replyStatus = UNKNOWN_TRANSACTION;
+                }
+            }
+        }
+    }
+
+    if (transaction->flags & IBinder::FLAG_ONEWAY) {
+        if (replyStatus != OK) {
+            ALOGW("Oneway call failed with error: %d", replyStatus);
+        }
+
+        LOG_RPC_DETAIL("Processed async transaction %" PRId64 " on %s", transaction->asyncNumber,
+                       addr.toString().c_str());
+
+        // Check to see if there is another asynchronous transaction to process.
+        // This behavior differs from binder behavior, since in the binder
+        // driver, asynchronous transactions will be processed after existing
+        // pending binder transactions on the queue. The downside of this is
+        // that asynchronous transactions can be drowned out by synchronous
+        // transactions. However, we have no easy way to queue these
+        // transactions after the synchronous transactions we may want to read
+        // from the wire. So, in socket binder here, we have the opposite
+        // downside: asynchronous transactions may drown out synchronous
+        // transactions.
+        {
+            std::unique_lock<std::mutex> _l(mNodeMutex);
+            auto it = mNodeForAddress.find(addr);
+            // last refcount dropped after this transaction happened
+            if (it == mNodeForAddress.end()) return OK;
+
+            // note - only updated now, instead of later, so that other threads
+            // will queue any later transactions
+
+            // TODO(b/183140903): support > 2**64 async transactions
+            //     (we can do this by allowing asyncNumber to wrap, since we
+            //     don't expect more than 2**64 simultaneous transactions)
+            it->second.asyncNumber++;
+
+            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());
+
+                // justification for const_cast (consider avoiding priority_queue):
+                // - AsyncTodo operator< doesn't depend on 'data' object
+                // - gotta go fast
+                std::vector<uint8_t> data = std::move(
+                        const_cast<BinderNode::AsyncTodo&>(it->second.asyncTodo.top()).data);
+                it->second.asyncTodo.pop();
+                _l.unlock();
+                return processTransactInternal(fd, connection, std::move(data));
+            }
+        }
+        return OK;
+    }
+
+    RpcWireReply rpcReply{
+            .status = replyStatus,
+    };
+
+    std::vector<uint8_t> replyData(sizeof(RpcWireReply) + reply.dataSize());
+    memcpy(replyData.data() + 0, &rpcReply, sizeof(RpcWireReply));
+    memcpy(replyData.data() + sizeof(RpcWireReply), reply.data(), reply.dataSize());
+
+    if (replyData.size() > std::numeric_limits<uint32_t>::max()) {
+        ALOGE("Reply size too big %zu", transactionData.size());
+        terminate();
+        return BAD_VALUE;
+    }
+
+    RpcWireHeader cmdReply{
+            .command = RPC_COMMAND_REPLY,
+            .bodySize = static_cast<uint32_t>(replyData.size()),
+    };
+
+    if (!rpcSend(fd, "reply header", &cmdReply, sizeof(RpcWireHeader))) {
+        return DEAD_OBJECT;
+    }
+    if (!rpcSend(fd, "reply body", replyData.data(), replyData.size())) {
+        return DEAD_OBJECT;
+    }
+    return OK;
+}
+
+status_t RpcState::processDecStrong(const base::unique_fd& fd, const RpcWireHeader& command) {
+    LOG_ALWAYS_FATAL_IF(command.command != RPC_COMMAND_DEC_STRONG, "command: %d", command.command);
+
+    std::vector<uint8_t> commandData(command.bodySize);
+    if (!rpcRec(fd, "dec ref body", commandData.data(), commandData.size())) {
+        return DEAD_OBJECT;
+    }
+
+    if (command.bodySize < sizeof(RpcWireAddress)) {
+        ALOGE("Expecting %zu but got %" PRId32 " bytes for RpcWireAddress. Terminating!",
+              sizeof(RpcWireAddress), command.bodySize);
+        terminate();
+        return BAD_VALUE;
+    }
+    RpcWireAddress* address = reinterpret_cast<RpcWireAddress*>(commandData.data());
+
+    // TODO(b/182939933): heap allocation just for lookup
+    auto addr = RpcAddress::fromRawEmbedded(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());
+        dump();
+        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());
+        terminate();
+        return BAD_VALUE;
+    }
+
+    if (it->second.timesSent == 0) {
+        ALOGE("No record of sending binder, but requested decStrong: %s", addr.toString().c_str());
+        return OK;
+    }
+
+    LOG_ALWAYS_FATAL_IF(it->second.sentRef == nullptr, "Inconsistent state, lost ref for %s",
+                        addr.toString().c_str());
+
+    sp<IBinder> tempHold;
+
+    it->second.timesSent--;
+    if (it->second.timesSent == 0) {
+        tempHold = it->second.sentRef;
+        it->second.sentRef = nullptr;
+
+        if (it->second.timesRecd == 0) {
+            mNodeForAddress.erase(it);
+        }
+    }
+
+    _l.unlock();
+    tempHold = nullptr; // destructor may make binder calls on this connection
+
+    return OK;
+}
+
+} // namespace android