NetNbns.cpp

//------------------------------------------------------------------------------
//This file is part of embKernel. 
//See license.txt for the full license governing this code.
//------------------------------------------------------------------------------

#include "Net.hpp"
#include "NetUdp.hpp"
#include "NetNbns.hpp"
#include "LibEndian.hpp"
#include <string.h>
#include <ctype.h>

void NetNbns::processFrame(NetDefs::FRAME& frame, NetDefs::NBNS_HEADER& header, int len) {
    uint8_t* questionEntry = ((uint8_t*) &header) + sizeof(NetDefs::NBNS_HEADER);

    for (int i = LibEndian::hwToBe(header.questions); i > 0; i--) {
        unsigned int labelLen = *questionEntry;

        uint16_t nbType = LibEndian::hwToBe(((uint16_t*) (&questionEntry[labelLen + 2]))[0]);
        uint16_t nbClass = LibEndian::hwToBe(((uint16_t*) (&questionEntry[labelLen + 2]))[1]);

        //Check the type and class
        if ((nbType == NetDefs::NBNS_TYPE_NB) && (nbClass == NetDefs::NBNS_CLASS_IN)) {
            bool result = true;
            uint8_t* data = &questionEntry[1];

            for (unsigned int j = 0; j < (labelLen >> 1); j++) {
                char c;

                c = (((*data++) - 'A') << 4);
                c |= ((*data++) - 'A');
                if (c == 0x20) {
                    c = 0;
                }
                c = toupper(c);
                if (c != toupper(Net::sConfig.deviceName[j]) || (j >= sizeof(Net::sConfig.deviceName))) {
                    result = false;
                    break;
                }
            }

            if (!result) {
                questionEntry += labelLen + 6;
                continue;
            }

            NetDefs::FRAME * sendFrame = Net::allocFrame(sizeof(NetDefs::MAC_HEADER) + sizeof(NetDefs::IP_HEADER) + sizeof(NetDefs::UDP_HEADER) + 128);

            if (!sendFrame) {
                questionEntry += labelLen + 6;
                continue;
            }

            sendFrame->types.nbns.nbnsHeader.id = header.id;
            sendFrame->types.nbns.nbnsHeader.flags = LibEndian::hwToBe((uint16_t) 0x8400);
            sendFrame->types.nbns.nbnsHeader.questions = 0;
            sendFrame->types.nbns.nbnsHeader.answers = LibEndian::hwToBe((uint16_t) 0x0001);
            sendFrame->types.nbns.nbnsHeader.authorities = 0;
            sendFrame->types.nbns.nbnsHeader.additionals = 0;

            memcpy(&sendFrame->types.nbns.data[0], questionEntry, labelLen + 2);
            const uint8_t trailer[] = {
                    0x00, 0x20, 0x00, 0x01, 0x00, 0x03, 0xF4, 0x80, 0x00, 0x06, 0x60, 0x00 };
            memcpy(&sendFrame->types.nbns.data[labelLen + 2], trailer, sizeof(trailer));
            memcpy(&sendFrame->types.nbns.data[labelLen + 2 + sizeof(trailer)], &Net::sConfig.ipAddr, sizeof(NetDefs::IP_ADDR));

            NetUdp::putHeader(*sendFrame, frame.types.mac.macHeader.srcAddr, frame.types.ip.ipHeader.srcAddr, frame.types.udp.udpHeader.srcPort,
                    NetDefs::UDP_PORT_NBNS, sizeof(NetDefs::NBNS_HEADER) + labelLen + 2 + sizeof(trailer) + sizeof(NetDefs::IP_ADDR));

            NetUdp::flush(*sendFrame, sizeof(NetDefs::NBNS_HEADER) + labelLen + 2 + sizeof(trailer) + sizeof(NetDefs::IP_ADDR), true);
            questionEntry += labelLen + 6;
        }
    }
    Net::freeFrame(frame);
}