/*
 * Copyright (C) 2014 Cloudius Systems, Ltd.
 */

#include "native-stack.hh"
#include "native-stack-impl.hh"
#include "net.hh"
#include "ip.hh"
#include "tcp-stack.hh"
#include "udp.hh"
#include "virtio.hh"
#include "xenfront.hh"
#include "proxy.hh"
#include <memory>
#include <queue>
#ifdef HAVE_OSV
#include <osv/firmware.hh>
#include <gnu/libc-version.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

namespace net {

// native_network_stack
class native_network_stack : public network_stack {
    static std::unique_ptr<native_network_stack> _s;
    interface _netif;
    ipv4 _inet;
    udp_v4 _udp;
    using tcp4 = tcp<ipv4_traits>;
public:
    explicit native_network_stack(boost::program_options::variables_map opts);
    virtual server_socket listen(socket_address sa, listen_options opt) override;
    virtual udp_channel make_udp_channel(ipv4_addr addr) override;
    static std::unique_ptr<network_stack> create(boost::program_options::variables_map opts) {
        return std::make_unique<native_network_stack>(opts);
    }
    friend class native_server_socket_impl<tcp4>;
};

udp_channel
native_network_stack::make_udp_channel(ipv4_addr addr) {
    return _udp.make_channel(addr);
}

enum class xen_info {
    nonxen = 0,
    userspace = 1,
    osv = 2,
};

static xen_info is_xen()
{
    struct stat buf;
    if (!stat("/proc/xen", &buf) || !stat("/dev/xen", &buf)) {
        return xen_info::userspace;
    }

#ifdef HAVE_OSV
    const char *str = gnu_get_libc_release();
    if (std::string("OSv") != str) {
        return xen_info::nonxen;
    }
    auto firmware = osv::firmware_vendor();
    if (firmware == "Xen") {
        return xen_info::osv;
    }
#endif

    return xen_info::nonxen;
}

std::unique_ptr<net::device> create_native_net_device(boost::program_options::variables_map opts) {

    if (!smp::main_thread()) {
        return create_proxy_net_device(opts);
    }

    auto xen = is_xen();
    if (xen == xen_info::nonxen) {
        return create_virtio_net_device(opts["tap-device"].as<std::string>(), opts);
    }
    return create_xenfront_net_device(opts, xen == xen_info::userspace);
}

void
add_native_net_options_description(boost::program_options::options_description &opts) {

    auto xen = is_xen();
    if (xen != xen_info::nonxen) {
        opts.add(get_xenfront_net_options_description());
    } else {
        opts.add(get_virtio_net_options_description());
    }
}

native_network_stack::native_network_stack(boost::program_options::variables_map opts)
    : _netif(create_native_net_device(opts))
    , _inet(&_netif)
    , _udp(_inet) {
    _inet.set_host_address(ipv4_address(opts["host-ipv4-addr"].as<std::string>()));
    _inet.set_gw_address(ipv4_address(opts["gw-ipv4-addr"].as<std::string>()));
    _inet.set_netmask_address(ipv4_address(opts["netmask-ipv4-addr"].as<std::string>()));
    _udp.set_queue_size(opts["udpv4-queue-size"].as<int>());
}

server_socket
native_network_stack::listen(socket_address sa, listen_options opts) {
    assert(sa.as_posix_sockaddr().sa_family == AF_INET);
    return tcpv4_listen(_inet.get_tcp(), ntohs(sa.as_posix_sockaddr_in().sin_port), opts);
}

std::unique_ptr<native_network_stack> native_network_stack::_s;

boost::program_options::options_description nns_options() {
    boost::program_options::options_description opts(
            "Native networking stack options");
    opts.add_options()
        ("tap-device",
                boost::program_options::value<std::string>()->default_value("tap0"),
                "tap device to connect to")
        ("host-ipv4-addr",
                boost::program_options::value<std::string>()->default_value("192.168.122.2"),
                "static IPv4 address to use")
        ("gw-ipv4-addr",
                boost::program_options::value<std::string>()->default_value("192.168.122.1"),
                "static IPv4 gateway to use")
        ("netmask-ipv4-addr",
                boost::program_options::value<std::string>()->default_value("255.255.255.0"),
                "static IPv4 netmask to use")
        ("udpv4-queue-size",
                boost::program_options::value<int>()->default_value(udp_v4::default_queue_size),
                "Default size of the UDPv4 per-channel packet queue")
        ;

    add_native_net_options_description(opts);
    return opts;
}

network_stack_registrator nns_registrator{
    "native", nns_options(), native_network_stack::create
};

}