1 files changed, 129 insertions, 0 deletions
diff --git a/wifi/netlinkinterceptor/aidl/default/InterceptorRelay.cpp b/wifi/netlinkinterceptor/aidl/default/InterceptorRelay.cpp
new file mode 100644
index 0000000000..ded9122a6f
--- /dev/null
+++ b/wifi/netlinkinterceptor/aidl/default/InterceptorRelay.cpp
@@ -0,0 +1,129 @@
+/*
+ * Copyright (C) 2021 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 "InterceptorRelay.h"
+
+#include <android-base/logging.h>
+#include <libnl++/printer.h>
+#include <poll.h>
+
+#include <chrono>
+
+#include "util.h"
+
+namespace android::nlinterceptor {
+using namespace std::chrono_literals;
+
+static constexpr std::chrono::milliseconds kPollTimeout = 300ms;
+static constexpr bool kSuperVerbose = true;
+
+InterceptorRelay::InterceptorRelay(uint32_t nlFamily, uint32_t clientNlPid,
+                                   const std::string& clientName)
+    : mClientName(clientName),
+      mNlSocket(std::make_optional<nl::Socket>(nlFamily, 0, 0)),
+      mClientNlPid(clientNlPid) {}
+
+InterceptorRelay::~InterceptorRelay() {
+    mRunning = false;
+    if (mRelayThread.joinable()) mRelayThread.join();
+}
+
+uint32_t InterceptorRelay::getPid() {
+    auto pidMaybe = mNlSocket->getPid();
+    CHECK(pidMaybe.has_value()) << "Failed to get pid of nl::Socket!";
+    return *pidMaybe;
+}
+
+void InterceptorRelay::relayMessages() {
+    pollfd fds[] = {
+        mNlSocket->preparePoll(POLLIN),
+    };
+    while (mRunning) {
+        if (poll(fds, countof(fds), kPollTimeout.count()) < 0) {
+            PLOG(FATAL) << "poll failed";
+            return;
+        }
+        const auto nlsockEvents = fds[0].revents;
+
+        if (isSocketBad(nlsockEvents)) {
+            LOG(ERROR) << "Netlink socket is bad";
+            mRunning = false;
+            return;
+        }
+        if (!isSocketReadable(nlsockEvents)) continue;
+
+        const auto [msgMaybe, sa] = mNlSocket->receiveFrom();
+        if (!msgMaybe.has_value()) {
+            LOG(ERROR) << "Failed to receive Netlink data!";
+            mRunning = false;
+            return;
+        }
+        const auto msg = *msgMaybe;
+        if (!msg.firstOk()) {
+            LOG(ERROR) << "Netlink packet is malformed!";
+            // Test messages might be empty, this isn't fatal.
+            continue;
+        }
+        if constexpr (kSuperVerbose) {
+            LOG(VERBOSE) << "[" << mClientName
+                         << "] nlMsg: " << nl::toString(msg, NETLINK_GENERIC);
+        }
+
+        uint32_t destinationPid = 0;
+        if (sa.nl_pid == 0) {
+            destinationPid = mClientNlPid;
+        }
+
+        if (!mNlSocket->send(msg, destinationPid)) {
+            LOG(ERROR) << "Failed to send Netlink message!";
+            mRunning = false;
+            return;
+        }
+    }
+    LOG(VERBOSE) << "[" << mClientName << "] Exiting relay thread!";
+}
+
+bool InterceptorRelay::start() {
+    if (mRunning) {
+        LOG(ERROR)
+            << "Can't relay messages: InterceptorRelay is already running!";
+        return false;
+    }
+    if (mRelayThread.joinable()) {
+        LOG(ERROR) << "relay thread is already running!";
+        return false;
+    }
+    if (!mNlSocket.has_value()) {
+        LOG(ERROR) << "Netlink socket not initialized!";
+        return false;
+    }
+
+    mRunning = true;
+    mRelayThread = std::thread(&InterceptorRelay::relayMessages, this);
+
+    LOG(VERBOSE) << "Relay threads initialized";
+    return true;
+}
+
+bool InterceptorRelay::subscribeGroup(uint32_t nlGroup) {
+    return mNlSocket->addMembership(nlGroup);
+}
+
+bool InterceptorRelay::unsubscribeGroup(uint32_t nlGroup) {
+    return mNlSocket->dropMembership(nlGroup);
+}
+
+}  // namespace android::nlinterceptor