/*
* --------------------------------------------------------------------------
* FixSegmentHeader
*
* Fix IP length, IP checksum, TCP sequence number and TCP checksum
* in the segment.
* --------------------------------------------------------------------------
*/
static NDIS_STATUS
FixSegmentHeader(PNET_BUFFER nb, UINT16 segmentSize, UINT32 seqNumber)
{
EthHdr *dstEth;
IPHdr *dstIP;
TCPHdr *dstTCP;
PMDL mdl;
PUINT8 bufferStart;
mdl = NET_BUFFER_FIRST_MDL(nb);
bufferStart = (PUINT8)MmGetSystemAddressForMdlSafe(mdl, LowPagePriority);
if (!bufferStart) {
return NDIS_STATUS_RESOURCES;
}
dstEth = (EthHdr *)(bufferStart + NET_BUFFER_CURRENT_MDL_OFFSET(nb));
ASSERT((INT)MmGetMdlByteCount(mdl) - NET_BUFFER_CURRENT_MDL_OFFSET(nb)
>= sizeof(EthHdr) + sizeof(IPHdr) + sizeof(TCPHdr));
dstIP = (IPHdr *)((PCHAR)dstEth + sizeof *dstEth);
dstTCP = (TCPHdr *)((PCHAR)dstIP + dstIP->ihl * 4);
ASSERT((INT)MmGetMdlByteCount(mdl) - NET_BUFFER_CURRENT_MDL_OFFSET(nb)
>= sizeof(EthHdr) + dstIP->ihl * 4 + TCP_HDR_LEN(dstTCP));
/* Fix IP length and checksum */
ASSERT(dstIP->protocol == IPPROTO_TCP);
dstIP->tot_len = htons(segmentSize + dstIP->ihl * 4 + TCP_HDR_LEN(dstTCP));
dstIP->check = 0;
dstIP->check = IPChecksum((UINT8 *)dstIP, dstIP->ihl * 4, 0);
/* Fix TCP checksum */
dstTCP->seq = htonl(seqNumber);
dstTCP->check =
IPPseudoChecksum((UINT32 *)&dstIP->saddr,
(UINT32 *)&dstIP->daddr,
IPPROTO_TCP, segmentSize + TCP_HDR_LEN(dstTCP));
dstTCP->check = CalculateChecksumNB(nb,
(UINT16)(NET_BUFFER_DATA_LENGTH(nb) - sizeof *dstEth - dstIP->ihl * 4),
sizeof *dstEth + dstIP->ihl * 4);
return STATUS_SUCCESS;
}
/*
*----------------------------------------------------------------------------
* OvsCalculateUDPChecksum
* Calculate UDP checksum
*----------------------------------------------------------------------------
*/
static __inline NDIS_STATUS
OvsCalculateUDPChecksum(PNET_BUFFER_LIST curNbl,
PNET_BUFFER curNb,
IPHdr *ipHdr,
UDPHdr *udpHdr,
UINT32 packetLength)
{
NDIS_TCP_IP_CHECKSUM_NET_BUFFER_LIST_INFO csumInfo;
UINT16 checkSum;
csumInfo.Value = NET_BUFFER_LIST_INFO(curNbl, TcpIpChecksumNetBufferListInfo);
/* Next check if UDP checksum has been calculated. */
if (!csumInfo.Receive.UdpChecksumSucceeded) {
UINT32 l4Payload;
checkSum = udpHdr->check;
l4Payload = packetLength - sizeof(EthHdr) - ipHdr->ihl * 4;
udpHdr->check = 0;
udpHdr->check =
IPPseudoChecksum((UINT32 *)&ipHdr->saddr,
(UINT32 *)&ipHdr->daddr,
IPPROTO_UDP, (UINT16)l4Payload);
udpHdr->check = CalculateChecksumNB(curNb, (UINT16)l4Payload,
sizeof(EthHdr) + ipHdr->ihl * 4);
if (checkSum != udpHdr->check) {
OVS_LOG_TRACE("UDP checksum incorrect.");
return NDIS_STATUS_INVALID_PACKET;
}
}
csumInfo.Receive.UdpChecksumSucceeded = 1;
NET_BUFFER_LIST_INFO(curNbl, TcpIpChecksumNetBufferListInfo) = csumInfo.Value;
return NDIS_STATUS_SUCCESS;
}
