/*
 * This file is open source software, licensed to you under the terms
 * of the Apache License, Version 2.0 (the "License").  See the NOTICE file
 * distributed with this work for additional information regarding copyright
 * ownership.  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.
 */
/*
 * Copyright (C) 2014 Cloudius Systems, Ltd.
 *
 */

#include <seastar/net/virtio.hh>
#include <seastar/net/dpdk.hh>
#include <seastar/core/reactor.hh>
#include <seastar/net/ip.hh>
#include <iostream>
#include <utility>
#include <algorithm>

using namespace seastar;
using namespace net;

void dump_packet(const packet& p) {
    std::cout << "rx:";
    auto f = p.frag(0);
    for (unsigned i = 0; i < std::min(f.size, size_t(30)); ++i) {
        char x[4];
        std::sprintf(x, " %02x", uint8_t(f.base[i]));
        std::cout << x;
    }
    std::cout << "\n";
}

future<> echo_packet(net::qp& netif, packet p) {
    auto f = p.frag(0);
    if (f.size < sizeof(eth_hdr)) {
        return make_ready_future<>();
    }
    auto pos = 0;
    auto eh = reinterpret_cast<eth_hdr*>(f.base + pos);
    pos += sizeof(*eh);
    *eh = ntoh(*eh);
    if (eh->eth_proto != 0x0800) {
        return make_ready_future<>();
    }
    auto iph = reinterpret_cast<ip_hdr*>(f.base + pos);
    *iph = ntoh(*iph);
    pos += iph->ihl * 4;
    if (iph->ver != 4 || iph->ihl < 5 || iph->ip_proto != 1) {
        return make_ready_future<>();
    }
    auto ip_len = iph->len;
    auto icmph = reinterpret_cast<icmp_hdr*>(f.base + pos);
    if (icmph->type != icmp_hdr::msg_type::echo_request) {
        return make_ready_future<>();
    }
    auto icmp_len = ip_len - iph->ihl * 4;
    std::swap(eh->src_mac, eh->dst_mac);
    std::swap(iph->src_ip, iph->dst_ip);
    icmph->type = icmp_hdr::msg_type::echo_reply;
    icmph->csum = 0;
    *iph = hton(*iph);
    *eh = hton(*eh);
    icmph->csum = ip_checksum(icmph, icmp_len);
    iph->csum = 0;
    iph->csum = ip_checksum(iph, iph->ihl * 4);
    return netif.send(std::move(p));
}

#ifdef SEASTAR_HAVE_DPDK
void usage()
{
    std::cout<<"Usage: echotest [-virtio|-dpdk]"<<std::endl;
    std::cout<<"   -virtio - use virtio backend (default)"<<std::endl;
    std::cout<<"   -dpdk   - use dpdk-pmd backend"<<std::endl;
}
#endif

int main(int ac, char** av) {
    std::unique_ptr<net::device> dnet;
    net::qp* vnet;

    boost::program_options::variables_map opts;
    opts.insert(std::make_pair("tap-device", boost::program_options::variable_value(std::string("tap0"), false)));

#ifdef SEASTAR_HAVE_DPDK
    if (ac > 2) {
        usage();
        return -1;
    }

    if ((ac == 1) || !std::strcmp(av[1], "-virtio")) {
        dnet = create_virtio_net_device(opts);
    } else if (!std::strcmp(av[1], "-dpdk")) {
        dnet = create_dpdk_net_device();
    } else {
        usage();
        return -1;
    }
#else
    dnet = create_virtio_net_device(opts);
#endif // SEASTAR_HAVE_DPDK

    auto qp = dnet->init_local_queue(opts, 0);
    vnet = qp.get();
    dnet->set_local_queue(std::move(qp));
    subscription<packet> rx =
        dnet->receive([vnet] (packet p) {
            return echo_packet(*vnet, std::move(p));
        });
    engine().run();
    return 0;
}