#include <cstring>

#include "UdpVpnClient.hpp"
#include "ip_header.hpp"

UdpVpnClient::UdpVpnClient(const struct sockaddr_in6& server) : UdpVpn() {
    memset(&_server_addr, 0, sizeof(_server_addr));
    set_server(server);
}

void UdpVpnClient::set_server(const struct sockaddr_in6& server_addr) {
    if(server_addr.sin6_family != AF_INET6)
        throw UdpVpn::InitializationError("Server address must be IPv6");

    memcpy(&_server_addr, &server_addr, sizeof(_server_addr));
}

void UdpVpnClient::receive_from_tun() {
    VpnPacket packet(_vpn_mtu);
    size_t nread = read_from_tun(packet);
    if(nread == 0)
        return;

    kdebugf("Transmitting %s -> %s, size %d\n",
            format_address(packet.get_ipv6_header().source.s6_addr),
            format_address(packet.get_ipv6_header().dest.s6_addr),
            nread);

    packet.prepare_for_sending();
    write_to_server(packet);
}

void UdpVpnClient::receive_from_udp() {
    VpnPacket packet(_vpn_mtu);
    sockaddr_in6 peer_addr;
    size_t nread = read_from_udp(packet, peer_addr);
    if(nread == 0)
        return;

    // Reinject into tun
    kdebugf("Receiving packet #%u of size %d from %s\n",
            packet.get_seqno(),
            nread,
            format_address(packet.get_ipv6_header().source.s6_addr));
    _tun_dev.write(packet.get_payload(), packet.get_payload_size());
}

size_t UdpVpnClient::write_to_server(const VpnPacket& packet) {
    ssize_t nsent;

    nsent = sendto(_socket, packet.get_data(), packet.get_data_size(),
            MSG_CONFIRM,
            (const struct sockaddr*) &_server_addr, sizeof(_server_addr));
    if(nsent < 0)
        throw NetError("Could not send UDP packet", errno, true);

    return (size_t) nsent;
}