// Processes an ICMP packet and generates an echo reply, if requested
// Note: the srcAdd parameter could be detected from the pNetIf
// However, when support for multiple IP addresses per interface is implemented
// passing the source address explicitely is better
void TCPIP_ICMP_Process(TCPIP_NET_IF* pNetIf, TCPIP_MAC_PACKET* pRxPkt, uint32_t destAdd, uint32_t srcAdd)
{
ICMP_HEADER *pRxHdr;
TCPIP_MAC_DATA_SEGMENT *pSeg;
TCPIP_UINT16_VAL checksum;
TCPIP_MAC_PKT_ACK_RES ackRes;
pRxHdr = (ICMP_HEADER*)pRxPkt->pTransportLayer;
ackRes = TCPIP_MAC_PKT_ACK_RX_OK;
while(true)
{
if(pRxPkt->totTransportLen < sizeof(*pRxHdr))
{
ackRes = TCPIP_MAC_PKT_ACK_STRUCT_ERR;
break;
}
// Validate the checksum
// The checksum data includes the precomputed checksum in the header
// so a valid packet will always have a checksum of 0x0000
// 1st segment
checksum.Val = ~TCPIP_Helper_CalcIPChecksum(pRxPkt->pTransportLayer, pRxPkt->pDSeg->segLen, 0);
// add the other possible data segments
for(pSeg = pRxPkt->pDSeg->next; pSeg != 0; pSeg = pSeg->next)
{
checksum.Val = ~TCPIP_Helper_CalcIPChecksum(pSeg->segLoad, pSeg->segLen, checksum.Val);
}
if((uint16_t)~checksum.Val != 0)
{
ackRes = TCPIP_MAC_PKT_ACK_CHKSUM_ERR;
break;
}
if(pRxHdr->vType == ICMP_TYPE_ECHO_REQUEST && pRxHdr->vCode == ICMP_CODE_ECHO_REQUEST)
{ // echo request
ackRes = _ICMPProcessEchoRequest(pNetIf, pRxPkt, destAdd, srcAdd);
break;
}
#if defined(TCPIP_STACK_USE_ICMP_CLIENT)
if(pRxHdr->vType == ICMP_TYPE_ECHO_REPLY && pRxHdr->vCode == ICMP_CODE_ECHO_REPLY)
{ // echo reply; check if our own
// Get the sequence number and identifier fields
TCPIP_UINT32_VAL userData;
IPV4_ADDR remoteIPAddr;
userData.w[0] = pRxHdr->wIdentifier;
userData.w[1] = pRxHdr->wSequenceNumber;
remoteIPAddr.Val = srcAdd;
// Send a message to the application-level Ping driver that we've received an Echo Reply
_ICMPNotifyClients(pNetIf, &remoteIPAddr, (void *)userData.v);
ackRes = TCPIP_MAC_PKT_ACK_RX_OK;
}
#endif
break;
}
TCPIP_PKT_PacketAcknowledge(pRxPkt, ackRes);
return;
}
// Processes an ICMP packet and generates an echo reply, if requested
static void TCPIP_ICMP_Process(void)
{
TCPIP_NET_IF* pNetIf;
TCPIP_MAC_PACKET* pRxPkt;
IPV4_HEADER* pIpv4Header;
uint32_t destAdd;
uint32_t srcAdd;
ICMP_HEADER* pRxHdr;
uint16_t icmpTotLength;
uint16_t checksum;
TCPIP_MAC_PKT_ACK_RES ackRes;
// extract queued ICMP packets
while((pRxPkt = _TCPIPStackModuleRxExtract(TCPIP_THIS_MODULE_ID)) != 0)
{
pNetIf = (TCPIP_NET_IF*)pRxPkt->pktIf;
pRxHdr = (ICMP_HEADER*)pRxPkt->pTransportLayer;
ackRes = TCPIP_MAC_PKT_ACK_RX_OK;
pIpv4Header = (IPV4_HEADER*)pRxPkt->pNetLayer;
destAdd = pIpv4Header->DestAddress.Val;
srcAdd = pIpv4Header->SourceAddress.Val;
while(true)
{
icmpTotLength = pRxPkt->totTransportLen;
if(icmpTotLength < sizeof(*pRxHdr))
{
ackRes = TCPIP_MAC_PKT_ACK_STRUCT_ERR;
break;
}
// Validate the checksum
// The checksum data includes the precomputed checksum in the header
// so a valid packet will always have a checksum of 0x0000
// 1st segment
if((pRxPkt->pktFlags & TCPIP_MAC_PKT_FLAG_SPLIT) != 0)
{
checksum = TCPIP_Helper_PacketChecksum(pRxPkt, (uint8_t*)pRxHdr, icmpTotLength, 0);
}
else
{
checksum = TCPIP_Helper_CalcIPChecksum((uint8_t*)pRxHdr, icmpTotLength, 0);
}
if(checksum != 0)
{
ackRes = TCPIP_MAC_PKT_ACK_CHKSUM_ERR;
break;
}
if(pRxHdr->vType == ICMP_TYPE_ECHO_REQUEST && pRxHdr->vCode == ICMP_CODE_ECHO_REQUEST)
{ // echo request
ackRes = _ICMPProcessEchoRequest(pNetIf, pRxPkt, destAdd, srcAdd);
break;
}
#if defined(TCPIP_STACK_USE_ICMP_CLIENT)
if(pRxHdr->vType == ICMP_TYPE_ECHO_REPLY && pRxHdr->vCode == ICMP_CODE_ECHO_REPLY)
{ // echo reply; check if our own
// Get the sequence number and identifier fields
#if (TCPIP_ICMP_CLIENT_USER_NOTIFICATION != 0)
TCPIP_UINT32_VAL userData;
IPV4_ADDR remoteIPAddr;
userData.w[0] = pRxHdr->wIdentifier;
userData.w[1] = pRxHdr->wSequenceNumber;
remoteIPAddr.Val = srcAdd;
// Send a message to the application-level Ping driver that we've received an Echo Reply
_ICMPNotifyClients(pNetIf, &remoteIPAddr, (void *)userData.v);
#endif // (TCPIP_ICMP_CLIENT_USER_NOTIFICATION != 0)
ackRes = TCPIP_MAC_PKT_ACK_RX_OK;
break;
}
#endif
// unknown type
ackRes = TCPIP_MAC_PKT_ACK_TYPE_ERR;
break;
}
TCPIP_PKT_FlightLog(pRxPkt, TCPIP_THIS_MODULE_ID, ackRes, 0);
TCPIP_PKT_PacketAcknowledge(pRxPkt, ackRes);
}
}
