/*
 * Copyright (C) 2008 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 <errno.h>
#include <stdio.h>
#include <string.h>

#include <sys/socket.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/un.h>

#include <linux/netlink.h>
#include <linux/rtnetlink.h>

#define LOG_TAG "Netd"

#include <log/log.h>

#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_log.h>
#include <linux/netfilter/nfnetlink_compat.h>

#include <arpa/inet.h>

#include "NetlinkManager.h"
#include "NetlinkHandler.h"

#include "pcap-netfilter-linux-android.h"

namespace android {
namespace net {

const int NetlinkManager::NFLOG_QUOTA_GROUP = 1;
const int NetlinkManager::NETFILTER_STRICT_GROUP = 2;
const int NetlinkManager::NFLOG_WAKEUP_GROUP = 3;

NetlinkManager *NetlinkManager::sInstance = nullptr;

NetlinkManager *NetlinkManager::Instance() {
    if (!sInstance)
        sInstance = new NetlinkManager();
    return sInstance;
}

NetlinkManager::NetlinkManager() {
    mBroadcaster = nullptr;
}

NetlinkManager::~NetlinkManager() {
}

NetlinkHandler *NetlinkManager::setupSocket(int *sock, int netlinkFamily,
    int groups, int format, bool configNflog) {

    struct sockaddr_nl nladdr;
    int sz = 64 * 1024;
    int on = 1;

    memset(&nladdr, 0, sizeof(nladdr));
    nladdr.nl_family = AF_NETLINK;
    // Kernel will assign a unique nl_pid if set to zero.
    nladdr.nl_pid = 0;
    nladdr.nl_groups = groups;

    if ((*sock = socket(PF_NETLINK, SOCK_DGRAM | SOCK_CLOEXEC, netlinkFamily)) < 0) {
        ALOGE("Unable to create netlink socket for family %d: %s", netlinkFamily, strerror(errno));
        return nullptr;
    }

    // When running in a net/user namespace, SO_RCVBUFFORCE will fail because
    // it will check for the CAP_NET_ADMIN capability in the root namespace.
    // Try using SO_RCVBUF if that fails.
    if (setsockopt(*sock, SOL_SOCKET, SO_RCVBUFFORCE, &sz, sizeof(sz)) < 0 &&
        setsockopt(*sock, SOL_SOCKET, SO_RCVBUF, &sz, sizeof(sz)) < 0) {
        ALOGE("Unable to set uevent socket SO_RCVBUF option: %s", strerror(errno));
        close(*sock);
        return nullptr;
    }

    if (setsockopt(*sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on)) < 0) {
        SLOGE("Unable to set uevent socket SO_PASSCRED option: %s", strerror(errno));
        close(*sock);
        return nullptr;
    }

    if (bind(*sock, (struct sockaddr *) &nladdr, sizeof(nladdr)) < 0) {
        ALOGE("Unable to bind netlink socket: %s", strerror(errno));
        close(*sock);
        return nullptr;
    }

    if (configNflog) {
        if (android_nflog_send_config_cmd(*sock, 0, NFULNL_CFG_CMD_PF_UNBIND, AF_INET) < 0) {
            ALOGE("Failed NFULNL_CFG_CMD_PF_UNBIND: %s", strerror(errno));
            return nullptr;
        }
        if (android_nflog_send_config_cmd(*sock, 0, NFULNL_CFG_CMD_PF_BIND, AF_INET) < 0) {
            ALOGE("Failed NFULNL_CFG_CMD_PF_BIND: %s", strerror(errno));
            return nullptr;
        }
        if (android_nflog_send_config_cmd(*sock, 0, NFULNL_CFG_CMD_BIND, AF_UNSPEC) < 0) {
            ALOGE("Failed NFULNL_CFG_CMD_BIND: %s", strerror(errno));
            return nullptr;
        }
    }

    NetlinkHandler *handler = new NetlinkHandler(this, *sock, format);
    if (handler->start()) {
        ALOGE("Unable to start NetlinkHandler: %s", strerror(errno));
        close(*sock);
        return nullptr;
    }

    return handler;
}

int NetlinkManager::start() {
    if ((mUeventHandler = setupSocket(&mUeventSock, NETLINK_KOBJECT_UEVENT,
         0xffffffff, NetlinkListener::NETLINK_FORMAT_ASCII, false)) == nullptr) {
        return -1;
    }

    if ((mRouteHandler = setupSocket(&mRouteSock, NETLINK_ROUTE,
                                     RTMGRP_LINK |
                                     RTMGRP_IPV4_IFADDR |
                                     RTMGRP_IPV6_IFADDR |
                                     RTMGRP_IPV6_ROUTE |
                                     (1 << (RTNLGRP_ND_USEROPT - 1)),
         NetlinkListener::NETLINK_FORMAT_BINARY, false)) == nullptr) {
        return -1;
    }

    if ((mQuotaHandler = setupSocket(&mQuotaSock, NETLINK_NFLOG,
            NFLOG_QUOTA_GROUP, NetlinkListener::NETLINK_FORMAT_BINARY, false)) == nullptr) {
        ALOGW("Unable to open qlog quota socket, check if xt_quota2 can send via UeventHandler");
        // TODO: return -1 once the emulator gets a new kernel.
    }

    if ((mStrictHandler = setupSocket(&mStrictSock, NETLINK_NETFILTER,
            0, NetlinkListener::NETLINK_FORMAT_BINARY_UNICAST, true)) == nullptr) {
        ALOGE("Unable to open strict socket");
        // TODO: return -1 once the emulator gets a new kernel.
    }

    return 0;
}

int NetlinkManager::stop() {
    int status = 0;

    if (mUeventHandler->stop()) {
        ALOGE("Unable to stop uevent NetlinkHandler: %s", strerror(errno));
        status = -1;
    }

    delete mUeventHandler;
    mUeventHandler = nullptr;

    close(mUeventSock);
    mUeventSock = -1;

    if (mRouteHandler->stop()) {
        ALOGE("Unable to stop route NetlinkHandler: %s", strerror(errno));
        status = -1;
    }

    delete mRouteHandler;
    mRouteHandler = nullptr;

    close(mRouteSock);
    mRouteSock = -1;

    if (mQuotaHandler) {
        if (mQuotaHandler->stop()) {
            ALOGE("Unable to stop quota NetlinkHandler: %s", strerror(errno));
            status = -1;
        }

        delete mQuotaHandler;
        mQuotaHandler = nullptr;

        close(mQuotaSock);
        mQuotaSock = -1;
    }

    if (mStrictHandler) {
        if (mStrictHandler->stop()) {
            ALOGE("Unable to stop strict NetlinkHandler: %s", strerror(errno));
            status = -1;
        }

        delete mStrictHandler;
        mStrictHandler = nullptr;

        close(mStrictSock);
        mStrictSock = -1;
    }

    return status;
}

}  // namespace net
}  // namespace android