Add WakeupController and NFLogListener

These classes work together to parse and dispatch NFLOG messages in
response to inbound packets annotated by the WiFi driver.

Test: as follows
    - built
    - flashed
    - booted
    - netd_unit_test passes

Change-Id: Id26d62858bf4bc4186ae66850f08077adf6fc2ac
diff --git a/server/WakeupController.cpp b/server/WakeupController.cpp
new file mode 100644
index 0000000..b3eae7e
--- /dev/null
+++ b/server/WakeupController.cpp
@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2017 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 "WakeupController"
+
+#include <endian.h>
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nfnetlink_log.h>
+#include <iostream>
+
+#include <android-base/stringprintf.h>
+#include <cutils/log.h>
+#include <netdutils/Netfilter.h>
+#include <netdutils/Netlink.h>
+
+#include "IptablesRestoreController.h"
+#include "NetlinkManager.h"
+#include "WakeupController.h"
+
+namespace android {
+namespace net {
+
+using base::StringPrintf;
+using netdutils::Slice;
+using netdutils::Status;
+
+const char WakeupController::LOCAL_MANGLE_INPUT[] = "wakeupctrl_mangle_INPUT";
+
+WakeupController::~WakeupController() {
+    expectOk(mListener->unsubscribe(NetlinkManager::NFLOG_WAKEUP_GROUP));
+}
+
+netdutils::Status WakeupController::init(NFLogListenerInterface* listener) {
+    mListener = listener;
+    const auto msgHandler = [this](const nlmsghdr&, const nfgenmsg&, const Slice msg) {
+        std::string prefix;
+        uid_t uid = -1;
+        gid_t gid = -1;
+        uint64_t timestampNs = -1;
+        const auto attrHandler = [&prefix, &uid, &gid, &timestampNs](const nlattr attr,
+                                                                     const Slice payload) {
+            switch (attr.nla_type) {
+                case NFULA_TIMESTAMP: {
+                    timespec timespec = {};
+                    extract(payload, timespec);
+                    constexpr uint64_t kNsPerS = 1000000000ULL;
+                    timestampNs = be32toh(timespec.tv_nsec) + (be32toh(timespec.tv_sec) * kNsPerS);
+                    break;
+                }
+                case NFULA_PREFIX:
+                    // Strip trailing '\0'
+                    prefix = toString(take(payload, payload.size() - 1));
+                    break;
+                case NFULA_UID:
+                    extract(payload, uid);
+                    uid = be32toh(uid);
+                    break;
+                case NFULA_GID:
+                    extract(payload, gid);
+                    gid = be32toh(gid);
+                    break;
+                default:
+                    break;
+            }
+        };
+        forEachNetlinkAttribute(msg, attrHandler);
+        mReport(prefix, uid, gid, timestampNs);
+    };
+    return mListener->subscribe(NetlinkManager::NFLOG_WAKEUP_GROUP, msgHandler);
+}
+
+Status WakeupController::addInterface(const std::string& ifName, const std::string& prefix,
+                                    uint32_t mark, uint32_t mask) {
+    return execIptables("-A", ifName, prefix, mark, mask);
+}
+
+Status WakeupController::delInterface(const std::string& ifName, const std::string& prefix,
+                                    uint32_t mark, uint32_t mask) {
+    return execIptables("-D", ifName, prefix, mark, mask);
+}
+
+Status WakeupController::execIptables(const std::string& action, const std::string& ifName,
+                                      const std::string& prefix, uint32_t mark, uint32_t mask) {
+    // NFLOG messages to batch before releasing to userspace
+    constexpr int kBatch = 8;
+    // Max log message rate in packets/second
+    constexpr int kRateLimit = 10;
+    const char kFormat[] =
+        "*mangle\n%s %s -i %s -j NFLOG --nflog-prefix %s --nflog-group %d --nflog-threshold %d"
+        " -m mark --mark 0x%08x/0x%08x -m limit --limit %d/s\nCOMMIT\n";
+    const auto cmd = StringPrintf(
+        kFormat, action.c_str(), WakeupController::LOCAL_MANGLE_INPUT, ifName.c_str(),
+        prefix.c_str(), NetlinkManager::NFLOG_WAKEUP_GROUP, kBatch, mark, mask, kRateLimit);
+
+    std::string out;
+    auto rv = mIptables->execute(V4V6, cmd, &out);
+    if (rv != 0) {
+        auto s = Status(rv, "Failed to execute iptables cmd: " + cmd + ", out: " + out);
+        ALOGE("%s", toString(s).c_str());
+        return s;
+    }
+    return netdutils::status::ok;
+}
+
+}  // namespace net
+}  // namespace android