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IPv4/Single: Update ARP table from gratuitous ARP packets #463

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IPv4/Single: Update ARP table from gratuitous ARP packets #463

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fa608e9
IPv4/Single: Update ARP table from gratuitous ARP packets
May 1, 2022
d346016
Removed an unnecessary test
May 1, 2022
1c8b20b
Added declaration of xHardwareAddress
May 15, 2022
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87 changes: 51 additions & 36 deletions FreeRTOS_ARP.c
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Original file line number Diff line number Diff line change
Expand Up @@ -248,43 +248,58 @@ eFrameProcessingResult_t eARPProcessPacket( ARPPacket_t * const pxARPFrame )
case ipARP_REQUEST:

/* The packet contained an ARP request. Was it for the IP
* address of the node running this code? And does the MAC
* address claim that it is coming from this device itself? */
if( ( ulTargetProtocolAddress == *ipLOCAL_IP_ADDRESS_POINTER ) &&
( memcmp( ( void * ) ipLOCAL_MAC_ADDRESS,
( void * ) ( pxARPHeader->xSenderHardwareAddress.ucBytes ),
ipMAC_ADDRESS_LENGTH_BYTES ) != 0 ) )
* address of the node running this code? */
if( ulTargetProtocolAddress == *ipLOCAL_IP_ADDRESS_POINTER )
{
iptraceSENDING_ARP_REPLY( ulSenderProtocolAddress );

/* The request is for the address of this node. Add the
* entry into the ARP cache, or refresh the entry if it
* already exists. */
vARPRefreshCacheEntry( &( pxARPHeader->xSenderHardwareAddress ), ulSenderProtocolAddress );

/* Generate a reply payload in the same buffer. */
pxARPHeader->usOperation = ( uint16_t ) ipARP_REPLY;

( void ) memcpy( &( pxARPHeader->xTargetHardwareAddress ),
&( pxARPHeader->xSenderHardwareAddress ),
sizeof( MACAddress_t ) );

pxARPHeader->ulTargetProtocolAddress = ulSenderProtocolAddress;

/*
* Use helper variables for memcpy() to remain
* compliant with MISRA Rule 21.15. These should be
* optimized away.
*/
pvCopySource = ipLOCAL_MAC_ADDRESS;
pvCopyDest = pxARPHeader->xSenderHardwareAddress.ucBytes;
( void ) memcpy( pvCopyDest, pvCopySource, sizeof( MACAddress_t ) );

pvCopySource = ipLOCAL_IP_ADDRESS_POINTER;
pvCopyDest = pxARPHeader->ucSenderProtocolAddress;
( void ) memcpy( pvCopyDest, pvCopySource, sizeof( pxARPHeader->ucSenderProtocolAddress ) );

eReturn = eReturnEthernetFrame;
/* Does the MAC address claim that it is coming
* from this device itself? */
if( memcmp( ( void * ) ipLOCAL_MAC_ADDRESS,
( void * ) ( pxARPHeader->xSenderHardwareAddress.ucBytes ),
ipMAC_ADDRESS_LENGTH_BYTES ) != 0 )
{
iptraceSENDING_ARP_REPLY( ulSenderProtocolAddress );

/* The request is for the address of this node. Add the
* entry into the ARP cache, or refresh the entry if it
* already exists. */
vARPRefreshCacheEntry( &( pxARPHeader->xSenderHardwareAddress ), ulSenderProtocolAddress );

/* Generate a reply payload in the same buffer. */
pxARPHeader->usOperation = ( uint16_t ) ipARP_REPLY;

( void ) memcpy( &( pxARPHeader->xTargetHardwareAddress ),
&( pxARPHeader->xSenderHardwareAddress ),
sizeof( MACAddress_t ) );

pxARPHeader->ulTargetProtocolAddress = ulSenderProtocolAddress;

/*
* Use helper variables for memcpy() to remain
* compliant with MISRA Rule 21.15. These should be
* optimized away.
*/
pvCopySource = ipLOCAL_MAC_ADDRESS;
pvCopyDest = pxARPHeader->xSenderHardwareAddress.ucBytes;
( void ) memcpy( pvCopyDest, pvCopySource, sizeof( MACAddress_t ) );

pvCopySource = ipLOCAL_IP_ADDRESS_POINTER;
pvCopyDest = pxARPHeader->ucSenderProtocolAddress;
( void ) memcpy( pvCopyDest, pvCopySource, sizeof( pxARPHeader->ucSenderProtocolAddress ) );

eReturn = eReturnEthernetFrame;
}
}
else if( ulSenderProtocolAddress == ulTargetProtocolAddress ) /* Gratuitous ARP request? */
{
MACAddress_t xHardwareAddress;

/* The request is a Gratuitous ARP message.
* Refresh the entry if it already exists. */
/* Determine the ARP cache status for the requested IP address. */
if( eARPGetCacheEntry( &( ulSenderProtocolAddress ), &( xHardwareAddress ) ) == eARPCacheHit )
{
vARPRefreshCacheEntry( &( pxARPHeader->xSenderHardwareAddress ), ulSenderProtocolAddress );
}
}

break;
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