#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() {
    char buffer[1500];
    size_t nread = read_from_tun(buffer, 1500);
    if(nread == 0)
        return;

    // Parse inner packet header -- assume IPv6 for now [FIXME]
    IPv6Header inner_header;
    if(!parse_ipv6_header(buffer, nread, inner_header)) {
        // Not a valid header -- ignore the packet
        debugf("Ignoring outgoing packet with invalid header\n");
        return;
    }

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

    write_to_server(buffer, nread);
}

void UdpVpnClient::receive_from_udp() {
    char buffer[1500];
    sockaddr_in6 peer_addr;
    size_t nread = read_from_udp(buffer, 1500, peer_addr);

    // Parse inner packet header -- assume IPv6 for now [FIXME]
    IPv6Header inner_header;
    if(!parse_ipv6_header(buffer, nread, inner_header)) {
        // Not a valid header -- ignore the packet
        debugf("Ignoring packet with invalid header\n");
        return;
    }

    // Reinject into tun
    kdebugf("Receiving packet of size %d from peer\n", nread);
    _tun_dev.write(buffer, nread);
}

size_t UdpVpnClient::write_to_server(const char* data, size_t len) {
    ssize_t nsent;

    nsent = sendto(_socket, data, len, 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;
}