icmp.c

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/*! \file icmp.c \brief ICMP Protocol Library. */
//*****************************************************************************
//
// File Name    : 'icmp.c'
// Title        : ICMP (Internet Control Message Protocol) Protocol Library
// Author       : Pascal Stang
// Created      : 9/10/2004
// Revised      : 7/3/2005
// Version      : 0.1
// Target MCU   : Atmel AVR series
// Editor Tabs  : 4
//
//*****************************************************************************

#include "global.h"
#include "net.h"
#include "nic.h"
#include "arp.h"
#include "icmp.h"

#include "rprintf.h"
#include "debug.h"

// global variables


// functions
void icmpInit(void)
{
}

void icmpIpIn(icmpip_hdr* packet)
{
    // check ICMP type
    switch(packet->icmp.type)
    {
    case ICMP_TYPE_ECHOREQUEST:
        // echo request
        icmpEchoRequest(packet);
        break;
    default:
        break;
    }
}

void icmpEchoRequest(icmpip_hdr* packet)
{
    uint32_t tempIp;

    #if NET_DEBUG >= 3
        icmpPrintHeader(packet);
        //debugPrintHexTable(htons(packet->ip.len), (u08*)packet);
    #endif
    
    // change type to reply
    packet->icmp.type = ICMP_TYPE_ECHOREPLY;
    // recalculate checksum
    packet->icmp.icmpchksum = 0;
    packet->icmp.icmpchksum = netChecksum((u08*)&packet->icmp, htons(packet->ip.len)-IP_HEADER_LEN);
    // return to sender
    tempIp = packet->ip.destipaddr;
    packet->ip.destipaddr = packet->ip.srcipaddr;
    packet->ip.srcipaddr = tempIp;
    // add ethernet routing
    arpIpOut((struct netEthIpHeader*)(((u08*)packet)-ETH_HEADER_LEN), 0);
    
    // debugging
    #if NET_DEBUG >= 2
        icmpPrintHeader(packet);
        //debugPrintHexTable(htons(packet->ip.len), (u08*)packet);
    #endif
    
    // send it (packet->ip.len+ETH_HEADER_LEN
    nicSend(htons(packet->ip.len)+ETH_HEADER_LEN, (((u08*)packet)-ETH_HEADER_LEN));
}

#ifdef ICMP_DEBUG_PRINT
void icmpPrintHeader(icmpip_hdr* packet)
{
    rprintfProgStrM("ICMP Packet:\r\n");
    // print source IP address
    rprintfProgStrM("SrcIpAddr: "); netPrintIPAddr(htonl(packet->ip.srcipaddr));    rprintfCRLF();
    // print dest IP address
    rprintfProgStrM("DstIpAddr: "); netPrintIPAddr(htonl(packet->ip.destipaddr));   rprintfCRLF();
    // print type
    rprintfProgStrM("Type   : ");
    switch(packet->icmp.type)
    {
    case ICMP_TYPE_ECHOREQUEST:     rprintfProgStrM("ECHO REQUEST"); break;
    case ICMP_TYPE_ECHOREPLY:       rprintfProgStrM("ECHO REPLY"); break;
    default:                        rprintfProgStrM("UNKNOWN"); break;
    }
    rprintfCRLF();
    // print code
    rprintfProgStrM("Code   : 0x"); rprintfu08(packet->icmp.icode);         rprintfCRLF();
}
#endif

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