/*********************************************************************
*
* PIC IP Module for Microchip TCP/IP Stack
*
*********************************************************************
* FileName: IP.C
* Dependencies: string.h
* StackTsk.h
* Helpers.h
* IP.h
* Processor: PIC18, PIC24F, PIC24H, dsPIC30F, dsPIC33F
* Complier: Microchip C18 v3.02 or higher
* Microchip C30 v2.01 or higher
* Company: Microchip Technology, Inc.
*
* Software License Agreement
*
* This software is owned by Microchip Technology Inc. ("Microchip")
* and is supplied to you for use exclusively as described in the
* associated software agreement. This software is protected by
* software and other intellectual property laws. Any use in
* violation of the software license may subject the user to criminal
* sanctions as well as civil liability. Copyright 2006 Microchip
* Technology Inc. All rights reserved.
*
* This software is provided "AS IS." MICROCHIP DISCLAIMS ALL
* WARRANTIES, EXPRESS, IMPLIED, STATUTORY OR OTHERWISE, NOT LIMITED
* TO MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND
* INFRINGEMENT. Microchip shall in no event be liable for special,
* incidental, or consequential damages.
*
*
* Author Date Comment
*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
* Nilesh Rajbharti 4/27/01 Original (Rev 1.0)
* Nilesh Rajbharti 2/9/02 Cleanup
* Nilesh Rajbharti 5/22/02 Rev 2.0 (See version.log for detail)
* Howard Schlunder 8/31/04 Beta Rev 0.9 (See version.log for detail)
* Howard Schlunder 1/5/06 Improved DMA checksum efficiency
********************************************************************/
#include <string.h>
#include "..\Include\StackTsk.h"
#include "..\Include\Helpers.h"
#include "..\Include\MAC.h"
#include "..\Include\IP.h"
// This is left shifted by 4. Actual value is 0x04.
#define IPv4 (0x40u)
#define IP_VERSION IPv4
// IHL (Internet Header Length) is # of DWORDs in a header.
// Since, we do not support options, our IP header length will be
// minimum i.e. 20 bytes : IHL = 20 / 4 = 5.
#define IP_IHL (0x05)
#define IP_SERVICE_NW_CTRL (0x07)
#define IP_SERVICE_IN_CTRL (0x06)
#define IP_SERVICE_ECP (0x05)
#define IP_SERVICE_OVR (0x04)
#define IP_SERVICE_FLASH (0x03)
#define IP_SERVICE_IMM (0x02)
#define IP_SERVICE_PRIOR (0x01)
#define IP_SERVICE_ROUTINE (0x00)
#define IP_SERVICE_N_DELAY (0x00)
#define IP_SERCICE_L_DELAY (0x08)
#define IP_SERVICE_N_THRPT (0x00)
#define IP_SERVICE_H_THRPT (0x10)
#define IP_SERVICE_N_RELIB (0x00)
#define IP_SERVICE_H_RELIB (0x20)
#define IP_SERVICE (IP_SERVICE_ROUTINE | IP_SERVICE_N_DELAY)
#define MY_IP_TTL (100) // Time-To-Live in Seconds
static WORD _Identifier = 0;
static BYTE IPHeaderLen;
static void SwapIPHeader(IP_HEADER* h);
/*********************************************************************
* Function: BOOL IPGetHeader( IP_ADDR *localIP,
* NODE_INFO *remote,
* BYTE *Protocol,
* WORD *len)
*
* PreCondition: MACGetHeader() == TRUE
*
* Input: localIP - Local node IP Address as received
* in current IP header.
* If this information is not required
* caller may pass NULL value.
* remote - Remote node info
* Protocol - Current packet protocol
* len - Current packet data length
*
* Output: TRUE, if valid packet was received
* FALSE otherwise
*
* Side Effects: None
*
* Note: Only one IP message can be received.
* Caller may not transmit and receive a message
* at the same time.
*
********************************************************************/
BOOL IPGetHeader(IP_ADDR *localIP,
NODE_INFO *remote,
BYTE *protocol,
WORD *len)
{
WORD_VAL CalcChecksum;
IP_HEADER header;
#if defined(NON_MCHP_MAC)
WORD_VAL ReceivedChecksum;
WORD checksums[2];
BYTE optionsLen;
#define MAX_OPTIONS_LEN (40) // As per RFC 791.
BYTE options[MAX_OPTIONS_LEN];
#endif
// Read IP header.
MACGetArray((BYTE*)&header, sizeof(header));
// Make sure that this is an IPv4 packet.
if ( (header.VersionIHL & 0xf0) != IP_VERSION )
return FALSE;
#if !defined(NON_MCHP_MAC)
IPHeaderLen = (header.VersionIHL & 0x0f) << 2;
// Validate the IP header. If it is correct, the checksum
// will come out to 0x0000 (because the header contains a
// precomputed checksum). A corrupt header will have a
// nonzero checksum.
CalcChecksum.Val = MACCalcRxChecksum(0, IPHeaderLen);
// Seek to the end of the IP header
MACSetRxBuffer(IPHeaderLen);
if(CalcChecksum.Val)
#else
// Calculate options length in this header, if there is any.
// IHL is in terms of numbers of 32-bit DWORDs; i.e. actual
// length is 4 times IHL.
optionsLen = ((header.VersionIHL & 0x0f) << 2) - sizeof(header);
// If there is any option(s), read it so that we can include them
// in checksum calculation.
if ( optionsLen > MAX_OPTIONS_LEN )
return FALSE;
if ( optionsLen > 0 )
MACGetArray(options, optionsLen);
// Save header checksum; clear it and recalculate it ourselves.
ReceivedChecksum.Val = header.HeaderChecksum;
header.HeaderChecksum = 0;
// Calculate checksum of header including options bytes.
checksums[0] = ~CalcIPChecksum((BYTE*)&header, sizeof(header));
// Calculate Options checksum too, if they are present.
if ( optionsLen > 0 )
checksums[1] = ~CalcIPChecksum((BYTE*)options, optionsLen);
else
checksums[1] = 0;
CalcChecksum.Val = CalcIPChecksum((BYTE*)checksums,
2 * sizeof(WORD));
// Make sure that checksum is correct
if ( ReceivedChecksum.Val != CalcChecksum.Val )
#endif
{
// Bad packet. The function caller will be notified by means of the FALSE
// return value and it should discard the packet.
return FALSE;
}
// Network to host conversion.
SwapIPHeader(&header);
// If caller is intrested, return destination IP address
// as seen in this IP header.
if ( localIP )
localIP->Val = header.DestAddress.Val;
remote->IPAddr.Val = header.SourceAddress.Val;
*protocol = header.Protocol;
#if !defined(NON_MCHP_MAC)
*len = header.TotalLength - IPHeaderLen;
#else
*len = header.TotalLength - optionsLen -
sizeof(header);
#endif
return TRUE;
}
/*********************************************************************
* Function: WORD IPPutHeader(NODE_INFO *remote,
* BYTE protocol,
* WORD len)
*
* PreCondition: IPIsTxReady() == TRUE
*
* Input: *remote - Destination node address
* protocol - Current packet protocol
* len - Current packet data length
*
* Output: (WORD)0
*
* Side Effects: None
*
* Note: Only one IP message can be transmitted at any
* time.
********************************************************************/
WORD IPPutHeader(NODE_INFO *remote,
BYTE protocol,
WORD len)
{
IP_HEADER header;
IPHeaderLen = sizeof(IP_HEADER);
header.VersionIHL = IP_VERSION | IP_IHL;
header.TypeOfService = IP_SERVICE;
header.TotalLength = sizeof(header) + len;
header.Identification = ++_Identifier;
header.FragmentInfo = 0;
header.TimeToLive = MY_IP_TTL;
header.Protocol = protocol;
header.HeaderChecksum = 0;
header.SourceAddress = AppConfig.MyIPAddr;
header.DestAddress.Val = remote->IPAddr.Val;
SwapIPHeader(&header);
#if defined(NON_MCHP_MAC)
header.HeaderChecksum = CalcIPChecksum((BYTE*)&header,
sizeof(header));
#endif
MACPutHeader(&remote->MACAddr, MAC_IP, (sizeof(header)+len));
MACPutArray((BYTE*)&header, sizeof(header));
#if !defined(NON_MCHP_MAC)
header.HeaderChecksum = MACCalcTxChecksum(0, sizeof(header));
MACSetTxBuffer(CurrentTxBuffer, 10); // 10 is the offset in header to the HeaderChecksum member
MACPutArray((BYTE*)&header.HeaderChecksum, 2);
MACSetTxBuffer(CurrentTxBuffer, sizeof(header)); // Seek back to the end of the packet
#endif
return 0x0;
}
/*********************************************************************
* Function: IPSetRxBuffer(WORD Offset)
*
* PreCondition: IPHeaderLen must have been intialized by
* IPGetHeader() or IPPutHeader()
*
* Input: Offset from beginning of IP data field
*
* Output: Next Read/Write access to receive buffer is
* set to Offset
*
* Side Effects: None
*
* Note: None
*
********************************************************************/
void IPSetRxBuffer(WORD Offset)
{
MACSetRxBuffer(Offset+IPHeaderLen);
}
static void SwapIPHeader(IP_HEADER* h)
{
h->TotalLength = swaps(h->TotalLength);
h->Identification = swaps(h->Identification);
h->HeaderChecksum = swaps(h->HeaderChecksum);
}