summaryrefslogtreecommitdiffstats
path: root/drivers/net/sk98lin/skcsum.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/net/sk98lin/skcsum.c')
-rw-r--r--drivers/net/sk98lin/skcsum.c871
1 files changed, 871 insertions, 0 deletions
diff --git a/drivers/net/sk98lin/skcsum.c b/drivers/net/sk98lin/skcsum.c
new file mode 100644
index 000000000000..38a6e7a631f3
--- /dev/null
+++ b/drivers/net/sk98lin/skcsum.c
@@ -0,0 +1,871 @@
+/******************************************************************************
+ *
+ * Name: skcsum.c
+ * Project: GEnesis, PCI Gigabit Ethernet Adapter
+ * Version: $Revision: 1.12 $
+ * Date: $Date: 2003/08/20 13:55:53 $
+ * Purpose: Store/verify Internet checksum in send/receive packets.
+ *
+ ******************************************************************************/
+
+/******************************************************************************
+ *
+ * (C)Copyright 1998-2003 SysKonnect GmbH.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * The information in this file is provided "AS IS" without warranty.
+ *
+ ******************************************************************************/
+
+#ifdef SK_USE_CSUM /* Check if CSUM is to be used. */
+
+#ifndef lint
+static const char SysKonnectFileId[] =
+ "@(#) $Id: skcsum.c,v 1.12 2003/08/20 13:55:53 mschmid Exp $ (C) SysKonnect.";
+#endif /* !lint */
+
+/******************************************************************************
+ *
+ * Description:
+ *
+ * This is the "GEnesis" common module "CSUM".
+ *
+ * This module contains the code necessary to calculate, store, and verify the
+ * Internet Checksum of IP, TCP, and UDP frames.
+ *
+ * "GEnesis" is an abbreviation of "Gigabit Ethernet Network System in Silicon"
+ * and is the code name of this SysKonnect project.
+ *
+ * Compilation Options:
+ *
+ * SK_USE_CSUM - Define if CSUM is to be used. Otherwise, CSUM will be an
+ * empty module.
+ *
+ * SKCS_OVERWRITE_PROTO - Define to overwrite the default protocol id
+ * definitions. In this case, all SKCS_PROTO_xxx definitions must be made
+ * external.
+ *
+ * SKCS_OVERWRITE_STATUS - Define to overwrite the default return status
+ * definitions. In this case, all SKCS_STATUS_xxx definitions must be made
+ * external.
+ *
+ * Include File Hierarchy:
+ *
+ * "h/skdrv1st.h"
+ * "h/skcsum.h"
+ * "h/sktypes.h"
+ * "h/skqueue.h"
+ * "h/skdrv2nd.h"
+ *
+ ******************************************************************************/
+
+#include "h/skdrv1st.h"
+#include "h/skcsum.h"
+#include "h/skdrv2nd.h"
+
+/* defines ********************************************************************/
+
+/* The size of an Ethernet MAC header. */
+#define SKCS_ETHERNET_MAC_HEADER_SIZE (6+6+2)
+
+/* The size of the used topology's MAC header. */
+#define SKCS_MAC_HEADER_SIZE SKCS_ETHERNET_MAC_HEADER_SIZE
+
+/* The size of the IP header without any option fields. */
+#define SKCS_IP_HEADER_SIZE 20
+
+/*
+ * Field offsets within the IP header.
+ */
+
+/* "Internet Header Version" and "Length". */
+#define SKCS_OFS_IP_HEADER_VERSION_AND_LENGTH 0
+
+/* "Total Length". */
+#define SKCS_OFS_IP_TOTAL_LENGTH 2
+
+/* "Flags" "Fragment Offset". */
+#define SKCS_OFS_IP_FLAGS_AND_FRAGMENT_OFFSET 6
+
+/* "Next Level Protocol" identifier. */
+#define SKCS_OFS_IP_NEXT_LEVEL_PROTOCOL 9
+
+/* Source IP address. */
+#define SKCS_OFS_IP_SOURCE_ADDRESS 12
+
+/* Destination IP address. */
+#define SKCS_OFS_IP_DESTINATION_ADDRESS 16
+
+
+/*
+ * Field offsets within the UDP header.
+ */
+
+/* UDP checksum. */
+#define SKCS_OFS_UDP_CHECKSUM 6
+
+/* IP "Next Level Protocol" identifiers (see RFC 790). */
+#define SKCS_PROTO_ID_TCP 6 /* Transport Control Protocol */
+#define SKCS_PROTO_ID_UDP 17 /* User Datagram Protocol */
+
+/* IP "Don't Fragment" bit. */
+#define SKCS_IP_DONT_FRAGMENT SKCS_HTON16(0x4000)
+
+/* Add a byte offset to a pointer. */
+#define SKCS_IDX(pPtr, Ofs) ((void *) ((char *) (pPtr) + (Ofs)))
+
+/*
+ * Macros that convert host to network representation and vice versa, i.e.
+ * little/big endian conversion on little endian machines only.
+ */
+#ifdef SK_LITTLE_ENDIAN
+#define SKCS_HTON16(Val16) (((unsigned) (Val16) >> 8) | (((Val16) & 0xff) << 8))
+#endif /* SK_LITTLE_ENDIAN */
+#ifdef SK_BIG_ENDIAN
+#define SKCS_HTON16(Val16) (Val16)
+#endif /* SK_BIG_ENDIAN */
+#define SKCS_NTOH16(Val16) SKCS_HTON16(Val16)
+
+/* typedefs *******************************************************************/
+
+/* function prototypes ********************************************************/
+
+/******************************************************************************
+ *
+ * SkCsGetSendInfo - get checksum information for a send packet
+ *
+ * Description:
+ * Get all checksum information necessary to send a TCP or UDP packet. The
+ * function checks the IP header passed to it. If the high-level protocol
+ * is either TCP or UDP the pseudo header checksum is calculated and
+ * returned.
+ *
+ * The function returns the total length of the IP header (including any
+ * IP option fields), which is the same as the start offset of the IP data
+ * which in turn is the start offset of the TCP or UDP header.
+ *
+ * The function also returns the TCP or UDP pseudo header checksum, which
+ * should be used as the start value for the hardware checksum calculation.
+ * (Note that any actual pseudo header checksum can never calculate to
+ * zero.)
+ *
+ * Note:
+ * There is a bug in the GENESIS ASIC which may lead to wrong checksums.
+ *
+ * Arguments:
+ * pAc - A pointer to the adapter context struct.
+ *
+ * pIpHeader - Pointer to IP header. Must be at least the IP header *not*
+ * including any option fields, i.e. at least 20 bytes.
+ *
+ * Note: This pointer will be used to address 8-, 16-, and 32-bit
+ * variables with the respective alignment offsets relative to the pointer.
+ * Thus, the pointer should point to a 32-bit aligned address. If the
+ * target system cannot address 32-bit variables on non 32-bit aligned
+ * addresses, then the pointer *must* point to a 32-bit aligned address.
+ *
+ * pPacketInfo - A pointer to the packet information structure for this
+ * packet. Before calling this SkCsGetSendInfo(), the following field must
+ * be initialized:
+ *
+ * ProtocolFlags - Initialize with any combination of
+ * SKCS_PROTO_XXX bit flags. SkCsGetSendInfo() will only work on
+ * the protocols specified here. Any protocol(s) not specified
+ * here will be ignored.
+ *
+ * Note: Only one checksum can be calculated in hardware. Thus, if
+ * SKCS_PROTO_IP is specified in the 'ProtocolFlags',
+ * SkCsGetSendInfo() must calculate the IP header checksum in
+ * software. It might be a better idea to have the calling
+ * protocol stack calculate the IP header checksum.
+ *
+ * Returns: N/A
+ * On return, the following fields in 'pPacketInfo' may or may not have
+ * been filled with information, depending on the protocol(s) found in the
+ * packet:
+ *
+ * ProtocolFlags - Returns the SKCS_PROTO_XXX bit flags of the protocol(s)
+ * that were both requested by the caller and actually found in the packet.
+ * Protocol(s) not specified by the caller and/or not found in the packet
+ * will have their respective SKCS_PROTO_XXX bit flags reset.
+ *
+ * Note: For IP fragments, TCP and UDP packet information is ignored.
+ *
+ * IpHeaderLength - The total length in bytes of the complete IP header
+ * including any option fields is returned here. This is the start offset
+ * of the IP data, i.e. the TCP or UDP header if present.
+ *
+ * IpHeaderChecksum - If IP has been specified in the 'ProtocolFlags', the
+ * 16-bit Internet Checksum of the IP header is returned here. This value
+ * is to be stored into the packet's 'IP Header Checksum' field.
+ *
+ * PseudoHeaderChecksum - If this is a TCP or UDP packet and if TCP or UDP
+ * has been specified in the 'ProtocolFlags', the 16-bit Internet Checksum
+ * of the TCP or UDP pseudo header is returned here.
+ */
+void SkCsGetSendInfo(
+SK_AC *pAc, /* Adapter context struct. */
+void *pIpHeader, /* IP header. */
+SKCS_PACKET_INFO *pPacketInfo, /* Packet information struct. */
+int NetNumber) /* Net number */
+{
+ /* Internet Header Version found in IP header. */
+ unsigned InternetHeaderVersion;
+
+ /* Length of the IP header as found in IP header. */
+ unsigned IpHeaderLength;
+
+ /* Bit field specifiying the desired/found protocols. */
+ unsigned ProtocolFlags;
+
+ /* Next level protocol identifier found in IP header. */
+ unsigned NextLevelProtocol;
+
+ /* Length of IP data portion. */
+ unsigned IpDataLength;
+
+ /* TCP/UDP pseudo header checksum. */
+ unsigned long PseudoHeaderChecksum;
+
+ /* Pointer to next level protocol statistics structure. */
+ SKCS_PROTO_STATS *NextLevelProtoStats;
+
+ /* Temporary variable. */
+ unsigned Tmp;
+
+ Tmp = *(SK_U8 *)
+ SKCS_IDX(pIpHeader, SKCS_OFS_IP_HEADER_VERSION_AND_LENGTH);
+
+ /* Get the Internet Header Version (IHV). */
+ /* Note: The IHV is stored in the upper four bits. */
+
+ InternetHeaderVersion = Tmp >> 4;
+
+ /* Check the Internet Header Version. */
+ /* Note: We currently only support IP version 4. */
+
+ if (InternetHeaderVersion != 4) { /* IPv4? */
+ SK_DBG_MSG(pAc, SK_DBGMOD_CSUM, SK_DBGCAT_ERR | SK_DBGCAT_TX,
+ ("Tx: Unknown Internet Header Version %u.\n",
+ InternetHeaderVersion));
+ pPacketInfo->ProtocolFlags = 0;
+ pAc->Csum.ProtoStats[NetNumber][SKCS_PROTO_STATS_IP].TxUnableCts++;
+ return;
+ }
+
+ /* Get the IP header length (IHL). */
+ /*
+ * Note: The IHL is stored in the lower four bits as the number of
+ * 4-byte words.
+ */
+
+ IpHeaderLength = (Tmp & 0xf) * 4;
+ pPacketInfo->IpHeaderLength = IpHeaderLength;
+
+ /* Check the IP header length. */
+
+ /* 04-Aug-1998 sw - Really check the IHL? Necessary? */
+
+ if (IpHeaderLength < 5*4) {
+ SK_DBG_MSG(pAc, SK_DBGMOD_CSUM, SK_DBGCAT_ERR | SK_DBGCAT_TX,
+ ("Tx: Invalid IP Header Length %u.\n", IpHeaderLength));
+ pPacketInfo->ProtocolFlags = 0;
+ pAc->Csum.ProtoStats[NetNumber][SKCS_PROTO_STATS_IP].TxUnableCts++;
+ return;
+ }
+
+ /* This is an IPv4 frame with a header of valid length. */
+
+ pAc->Csum.ProtoStats[NetNumber][SKCS_PROTO_STATS_IP].TxOkCts++;
+
+ /* Check if we should calculate the IP header checksum. */
+
+ ProtocolFlags = pPacketInfo->ProtocolFlags;
+
+ if (ProtocolFlags & SKCS_PROTO_IP) {
+ pPacketInfo->IpHeaderChecksum =
+ SkCsCalculateChecksum(pIpHeader, IpHeaderLength);
+ }
+
+ /* Get the next level protocol identifier. */
+
+ NextLevelProtocol =
+ *(SK_U8 *) SKCS_IDX(pIpHeader, SKCS_OFS_IP_NEXT_LEVEL_PROTOCOL);
+
+ /*
+ * Check if this is a TCP or UDP frame and if we should calculate the
+ * TCP/UDP pseudo header checksum.
+ *
+ * Also clear all protocol bit flags of protocols not present in the
+ * frame.
+ */
+
+ if ((ProtocolFlags & SKCS_PROTO_TCP) != 0 &&
+ NextLevelProtocol == SKCS_PROTO_ID_TCP) {
+ /* TCP/IP frame. */
+ ProtocolFlags &= SKCS_PROTO_TCP | SKCS_PROTO_IP;
+ NextLevelProtoStats =
+ &pAc->Csum.ProtoStats[NetNumber][SKCS_PROTO_STATS_TCP];
+ }
+ else if ((ProtocolFlags & SKCS_PROTO_UDP) != 0 &&
+ NextLevelProtocol == SKCS_PROTO_ID_UDP) {
+ /* UDP/IP frame. */
+ ProtocolFlags &= SKCS_PROTO_UDP | SKCS_PROTO_IP;
+ NextLevelProtoStats =
+ &pAc->Csum.ProtoStats[NetNumber][SKCS_PROTO_STATS_UDP];
+ }
+ else {
+ /*
+ * Either not a TCP or UDP frame and/or TCP/UDP processing not
+ * specified.
+ */
+ pPacketInfo->ProtocolFlags = ProtocolFlags & SKCS_PROTO_IP;
+ return;
+ }
+
+ /* Check if this is an IP fragment. */
+
+ /*
+ * Note: An IP fragment has a non-zero "Fragment Offset" field and/or
+ * the "More Fragments" bit set. Thus, if both the "Fragment Offset"
+ * and the "More Fragments" are zero, it is *not* a fragment. We can
+ * easily check both at the same time since they are in the same 16-bit
+ * word.
+ */
+
+ if ((*(SK_U16 *)
+ SKCS_IDX(pIpHeader, SKCS_OFS_IP_FLAGS_AND_FRAGMENT_OFFSET) &
+ ~SKCS_IP_DONT_FRAGMENT) != 0) {
+ /* IP fragment; ignore all other protocols. */
+ pPacketInfo->ProtocolFlags = ProtocolFlags & SKCS_PROTO_IP;
+ NextLevelProtoStats->TxUnableCts++;
+ return;
+ }
+
+ /*
+ * Calculate the TCP/UDP pseudo header checksum.
+ */
+
+ /* Get total length of IP header and data. */
+
+ IpDataLength =
+ *(SK_U16 *) SKCS_IDX(pIpHeader, SKCS_OFS_IP_TOTAL_LENGTH);
+
+ /* Get length of IP data portion. */
+
+ IpDataLength = SKCS_NTOH16(IpDataLength) - IpHeaderLength;
+
+ /* Calculate the sum of all pseudo header fields (16-bit). */
+
+ PseudoHeaderChecksum =
+ (unsigned long) *(SK_U16 *) SKCS_IDX(pIpHeader,
+ SKCS_OFS_IP_SOURCE_ADDRESS + 0) +
+ (unsigned long) *(SK_U16 *) SKCS_IDX(pIpHeader,
+ SKCS_OFS_IP_SOURCE_ADDRESS + 2) +
+ (unsigned long) *(SK_U16 *) SKCS_IDX(pIpHeader,
+ SKCS_OFS_IP_DESTINATION_ADDRESS + 0) +
+ (unsigned long) *(SK_U16 *) SKCS_IDX(pIpHeader,
+ SKCS_OFS_IP_DESTINATION_ADDRESS + 2) +
+ (unsigned long) SKCS_HTON16(NextLevelProtocol) +
+ (unsigned long) SKCS_HTON16(IpDataLength);
+
+ /* Add-in any carries. */
+
+ SKCS_OC_ADD(PseudoHeaderChecksum, PseudoHeaderChecksum, 0);
+
+ /* Add-in any new carry. */
+
+ SKCS_OC_ADD(pPacketInfo->PseudoHeaderChecksum, PseudoHeaderChecksum, 0);
+
+ pPacketInfo->ProtocolFlags = ProtocolFlags;
+ NextLevelProtoStats->TxOkCts++; /* Success. */
+} /* SkCsGetSendInfo */
+
+
+/******************************************************************************
+ *
+ * SkCsGetReceiveInfo - verify checksum information for a received packet
+ *
+ * Description:
+ * Verify a received frame's checksum. The function returns a status code
+ * reflecting the result of the verification.
+ *
+ * Note:
+ * Before calling this function you have to verify that the frame is
+ * not padded and Checksum1 and Checksum2 are bigger than 1.
+ *
+ * Arguments:
+ * pAc - Pointer to adapter context struct.
+ *
+ * pIpHeader - Pointer to IP header. Must be at least the length in bytes
+ * of the received IP header including any option fields. For UDP packets,
+ * 8 additional bytes are needed to access the UDP checksum.
+ *
+ * Note: The actual length of the IP header is stored in the lower four
+ * bits of the first octet of the IP header as the number of 4-byte words,
+ * so it must be multiplied by four to get the length in bytes. Thus, the
+ * maximum IP header length is 15 * 4 = 60 bytes.
+ *
+ * Checksum1 - The first 16-bit Internet Checksum calculated by the
+ * hardware starting at the offset returned by SkCsSetReceiveFlags().
+ *
+ * Checksum2 - The second 16-bit Internet Checksum calculated by the
+ * hardware starting at the offset returned by SkCsSetReceiveFlags().
+ *
+ * Returns:
+ * SKCS_STATUS_UNKNOWN_IP_VERSION - Not an IP v4 frame.
+ * SKCS_STATUS_IP_CSUM_ERROR - IP checksum error.
+ * SKCS_STATUS_IP_CSUM_ERROR_TCP - IP checksum error in TCP frame.
+ * SKCS_STATUS_IP_CSUM_ERROR_UDP - IP checksum error in UDP frame
+ * SKCS_STATUS_IP_FRAGMENT - IP fragment (IP checksum ok).
+ * SKCS_STATUS_IP_CSUM_OK - IP checksum ok (not a TCP or UDP frame).
+ * SKCS_STATUS_TCP_CSUM_ERROR - TCP checksum error (IP checksum ok).
+ * SKCS_STATUS_UDP_CSUM_ERROR - UDP checksum error (IP checksum ok).
+ * SKCS_STATUS_TCP_CSUM_OK - IP and TCP checksum ok.
+ * SKCS_STATUS_UDP_CSUM_OK - IP and UDP checksum ok.
+ * SKCS_STATUS_IP_CSUM_OK_NO_UDP - IP checksum OK and no UDP checksum.
+ *
+ * Note: If SKCS_OVERWRITE_STATUS is defined, the SKCS_STATUS_XXX values
+ * returned here can be defined in some header file by the module using CSUM.
+ * In this way, the calling module can assign return values for its own needs,
+ * e.g. by assigning bit flags to the individual protocols.
+ */
+SKCS_STATUS SkCsGetReceiveInfo(
+SK_AC *pAc, /* Adapter context struct. */
+void *pIpHeader, /* IP header. */
+unsigned Checksum1, /* Hardware checksum 1. */
+unsigned Checksum2, /* Hardware checksum 2. */
+int NetNumber) /* Net number */
+{
+ /* Internet Header Version found in IP header. */
+ unsigned InternetHeaderVersion;
+
+ /* Length of the IP header as found in IP header. */
+ unsigned IpHeaderLength;
+
+ /* Length of IP data portion. */
+ unsigned IpDataLength;
+
+ /* IP header checksum. */
+ unsigned IpHeaderChecksum;
+
+ /* IP header options checksum, if any. */
+ unsigned IpOptionsChecksum;
+
+ /* IP data checksum, i.e. TCP/UDP checksum. */
+ unsigned IpDataChecksum;
+
+ /* Next level protocol identifier found in IP header. */
+ unsigned NextLevelProtocol;
+
+ /* The checksum of the "next level protocol", i.e. TCP or UDP. */
+ unsigned long NextLevelProtocolChecksum;
+
+ /* Pointer to next level protocol statistics structure. */
+ SKCS_PROTO_STATS *NextLevelProtoStats;
+
+ /* Temporary variable. */
+ unsigned Tmp;
+
+ Tmp = *(SK_U8 *)
+ SKCS_IDX(pIpHeader, SKCS_OFS_IP_HEADER_VERSION_AND_LENGTH);
+
+ /* Get the Internet Header Version (IHV). */
+ /* Note: The IHV is stored in the upper four bits. */
+
+ InternetHeaderVersion = Tmp >> 4;
+
+ /* Check the Internet Header Version. */
+ /* Note: We currently only support IP version 4. */
+
+ if (InternetHeaderVersion != 4) { /* IPv4? */
+ SK_DBG_MSG(pAc, SK_DBGMOD_CSUM, SK_DBGCAT_ERR | SK_DBGCAT_RX,
+ ("Rx: Unknown Internet Header Version %u.\n",
+ InternetHeaderVersion));
+ pAc->Csum.ProtoStats[NetNumber][SKCS_PROTO_STATS_IP].RxUnableCts++;
+ return (SKCS_STATUS_UNKNOWN_IP_VERSION);
+ }
+
+ /* Get the IP header length (IHL). */
+ /*
+ * Note: The IHL is stored in the lower four bits as the number of
+ * 4-byte words.
+ */
+
+ IpHeaderLength = (Tmp & 0xf) * 4;
+
+ /* Check the IP header length. */
+
+ /* 04-Aug-1998 sw - Really check the IHL? Necessary? */
+
+ if (IpHeaderLength < 5*4) {
+ SK_DBG_MSG(pAc, SK_DBGMOD_CSUM, SK_DBGCAT_ERR | SK_DBGCAT_RX,
+ ("Rx: Invalid IP Header Length %u.\n", IpHeaderLength));
+ pAc->Csum.ProtoStats[NetNumber][SKCS_PROTO_STATS_IP].RxErrCts++;
+ return (SKCS_STATUS_IP_CSUM_ERROR);
+ }
+
+ /* This is an IPv4 frame with a header of valid length. */
+
+ /* Get the IP header and data checksum. */
+
+ IpDataChecksum = Checksum2;
+
+ /*
+ * The IP header checksum is calculated as follows:
+ *
+ * IpHeaderChecksum = Checksum1 - Checksum2
+ */
+
+ SKCS_OC_SUB(IpHeaderChecksum, Checksum1, Checksum2);
+
+ /* Check if any IP header options. */
+
+ if (IpHeaderLength > SKCS_IP_HEADER_SIZE) {
+
+ /* Get the IP options checksum. */
+
+ IpOptionsChecksum = SkCsCalculateChecksum(
+ SKCS_IDX(pIpHeader, SKCS_IP_HEADER_SIZE),
+ IpHeaderLength - SKCS_IP_HEADER_SIZE);
+
+ /* Adjust the IP header and IP data checksums. */
+
+ SKCS_OC_ADD(IpHeaderChecksum, IpHeaderChecksum, IpOptionsChecksum);
+
+ SKCS_OC_SUB(IpDataChecksum, IpDataChecksum, IpOptionsChecksum);
+ }
+
+ /*
+ * Check if the IP header checksum is ok.
+ *
+ * NOTE: We must check the IP header checksum even if the caller just wants
+ * us to check upper-layer checksums, because we cannot do any further
+ * processing of the packet without a valid IP checksum.
+ */
+
+ /* Get the next level protocol identifier. */
+
+ NextLevelProtocol = *(SK_U8 *)
+ SKCS_IDX(pIpHeader, SKCS_OFS_IP_NEXT_LEVEL_PROTOCOL);
+
+ if (IpHeaderChecksum != 0xffff) {
+ pAc->Csum.ProtoStats[NetNumber][SKCS_PROTO_STATS_IP].RxErrCts++;
+ /* the NDIS tester wants to know the upper level protocol too */
+ if (NextLevelProtocol == SKCS_PROTO_ID_TCP) {
+ return(SKCS_STATUS_IP_CSUM_ERROR_TCP);
+ }
+ else if (NextLevelProtocol == SKCS_PROTO_ID_UDP) {
+ return(SKCS_STATUS_IP_CSUM_ERROR_UDP);
+ }
+ return (SKCS_STATUS_IP_CSUM_ERROR);
+ }
+
+ /*
+ * Check if this is a TCP or UDP frame and if we should calculate the
+ * TCP/UDP pseudo header checksum.
+ *
+ * Also clear all protocol bit flags of protocols not present in the
+ * frame.
+ */
+
+ if ((pAc->Csum.ReceiveFlags[NetNumber] & SKCS_PROTO_TCP) != 0 &&
+ NextLevelProtocol == SKCS_PROTO_ID_TCP) {
+ /* TCP/IP frame. */
+ NextLevelProtoStats =
+ &pAc->Csum.ProtoStats[NetNumber][SKCS_PROTO_STATS_TCP];
+ }
+ else if ((pAc->Csum.ReceiveFlags[NetNumber] & SKCS_PROTO_UDP) != 0 &&
+ NextLevelProtocol == SKCS_PROTO_ID_UDP) {
+ /* UDP/IP frame. */
+ NextLevelProtoStats =
+ &pAc->Csum.ProtoStats[NetNumber][SKCS_PROTO_STATS_UDP];
+ }
+ else {
+ /*
+ * Either not a TCP or UDP frame and/or TCP/UDP processing not
+ * specified.
+ */
+ return (SKCS_STATUS_IP_CSUM_OK);
+ }
+
+ /* Check if this is an IP fragment. */
+
+ /*
+ * Note: An IP fragment has a non-zero "Fragment Offset" field and/or
+ * the "More Fragments" bit set. Thus, if both the "Fragment Offset"
+ * and the "More Fragments" are zero, it is *not* a fragment. We can
+ * easily check both at the same time since they are in the same 16-bit
+ * word.
+ */
+
+ if ((*(SK_U16 *)
+ SKCS_IDX(pIpHeader, SKCS_OFS_IP_FLAGS_AND_FRAGMENT_OFFSET) &
+ ~SKCS_IP_DONT_FRAGMENT) != 0) {
+ /* IP fragment; ignore all other protocols. */
+ NextLevelProtoStats->RxUnableCts++;
+ return (SKCS_STATUS_IP_FRAGMENT);
+ }
+
+ /*
+ * 08-May-2000 ra
+ *
+ * From RFC 768 (UDP)
+ * If the computed checksum is zero, it is transmitted as all ones (the
+ * equivalent in one's complement arithmetic). An all zero transmitted
+ * checksum value means that the transmitter generated no checksum (for
+ * debugging or for higher level protocols that don't care).
+ */
+
+ if (NextLevelProtocol == SKCS_PROTO_ID_UDP &&
+ *(SK_U16*)SKCS_IDX(pIpHeader, IpHeaderLength + 6) == 0x0000) {
+
+ NextLevelProtoStats->RxOkCts++;
+
+ return (SKCS_STATUS_IP_CSUM_OK_NO_UDP);
+ }
+
+ /*
+ * Calculate the TCP/UDP checksum.
+ */
+
+ /* Get total length of IP header and data. */
+
+ IpDataLength =
+ *(SK_U16 *) SKCS_IDX(pIpHeader, SKCS_OFS_IP_TOTAL_LENGTH);
+
+ /* Get length of IP data portion. */
+
+ IpDataLength = SKCS_NTOH16(IpDataLength) - IpHeaderLength;
+
+ NextLevelProtocolChecksum =
+
+ /* Calculate the pseudo header checksum. */
+
+ (unsigned long) *(SK_U16 *) SKCS_IDX(pIpHeader,
+ SKCS_OFS_IP_SOURCE_ADDRESS + 0) +
+ (unsigned long) *(SK_U16 *) SKCS_IDX(pIpHeader,
+ SKCS_OFS_IP_SOURCE_ADDRESS + 2) +
+ (unsigned long) *(SK_U16 *) SKCS_IDX(pIpHeader,
+ SKCS_OFS_IP_DESTINATION_ADDRESS + 0) +
+ (unsigned long) *(SK_U16 *) SKCS_IDX(pIpHeader,
+ SKCS_OFS_IP_DESTINATION_ADDRESS + 2) +
+ (unsigned long) SKCS_HTON16(NextLevelProtocol) +
+ (unsigned long) SKCS_HTON16(IpDataLength) +
+
+ /* Add the TCP/UDP header checksum. */
+
+ (unsigned long) IpDataChecksum;
+
+ /* Add-in any carries. */
+
+ SKCS_OC_ADD(NextLevelProtocolChecksum, NextLevelProtocolChecksum, 0);
+
+ /* Add-in any new carry. */
+
+ SKCS_OC_ADD(NextLevelProtocolChecksum, NextLevelProtocolChecksum, 0);
+
+ /* Check if the TCP/UDP checksum is ok. */
+
+ if ((unsigned) NextLevelProtocolChecksum == 0xffff) {
+
+ /* TCP/UDP checksum ok. */
+
+ NextLevelProtoStats->RxOkCts++;
+
+ return (NextLevelProtocol == SKCS_PROTO_ID_TCP ?
+ SKCS_STATUS_TCP_CSUM_OK : SKCS_STATUS_UDP_CSUM_OK);
+ }
+
+ /* TCP/UDP checksum error. */
+
+ NextLevelProtoStats->RxErrCts++;
+
+ return (NextLevelProtocol == SKCS_PROTO_ID_TCP ?
+ SKCS_STATUS_TCP_CSUM_ERROR : SKCS_STATUS_UDP_CSUM_ERROR);
+} /* SkCsGetReceiveInfo */
+
+
+/******************************************************************************
+ *
+ * SkCsSetReceiveFlags - set checksum receive flags
+ *
+ * Description:
+ * Use this function to set the various receive flags. According to the
+ * protocol flags set by the caller, the start offsets within received
+ * packets of the two hardware checksums are returned. These offsets must
+ * be stored in all receive descriptors.
+ *
+ * Arguments:
+ * pAc - Pointer to adapter context struct.
+ *
+ * ReceiveFlags - Any combination of SK_PROTO_XXX flags of the protocols
+ * for which the caller wants checksum information on received frames.
+ *
+ * pChecksum1Offset - The start offset of the first receive descriptor
+ * hardware checksum to be calculated for received frames is returned
+ * here.
+ *
+ * pChecksum2Offset - The start offset of the second receive descriptor
+ * hardware checksum to be calculated for received frames is returned
+ * here.
+ *
+ * Returns: N/A
+ * Returns the two hardware checksum start offsets.
+ */
+void SkCsSetReceiveFlags(
+SK_AC *pAc, /* Adapter context struct. */
+unsigned ReceiveFlags, /* New receive flags. */
+unsigned *pChecksum1Offset, /* Offset for hardware checksum 1. */
+unsigned *pChecksum2Offset, /* Offset for hardware checksum 2. */
+int NetNumber)
+{
+ /* Save the receive flags. */
+
+ pAc->Csum.ReceiveFlags[NetNumber] = ReceiveFlags;
+
+ /* First checksum start offset is the IP header. */
+ *pChecksum1Offset = SKCS_MAC_HEADER_SIZE;
+
+ /*
+ * Second checksum start offset is the IP data. Note that this may vary
+ * if there are any IP header options in the actual packet.
+ */
+ *pChecksum2Offset = SKCS_MAC_HEADER_SIZE + SKCS_IP_HEADER_SIZE;
+} /* SkCsSetReceiveFlags */
+
+#ifndef SK_CS_CALCULATE_CHECKSUM
+
+/******************************************************************************
+ *
+ * SkCsCalculateChecksum - calculate checksum for specified data
+ *
+ * Description:
+ * Calculate and return the 16-bit Internet Checksum for the specified
+ * data.
+ *
+ * Arguments:
+ * pData - Pointer to data for which the checksum shall be calculated.
+ * Note: The pointer should be aligned on a 16-bit boundary.
+ *
+ * Length - Length in bytes of data to checksum.
+ *
+ * Returns:
+ * The 16-bit Internet Checksum for the specified data.
+ *
+ * Note: The checksum is calculated in the machine's natural byte order,
+ * i.e. little vs. big endian. Thus, the resulting checksum is different
+ * for the same input data on little and big endian machines.
+ *
+ * However, when written back to the network packet, the byte order is
+ * always in correct network order.
+ */
+unsigned SkCsCalculateChecksum(
+void *pData, /* Data to checksum. */
+unsigned Length) /* Length of data. */
+{
+ SK_U16 *pU16; /* Pointer to the data as 16-bit words. */
+ unsigned long Checksum; /* Checksum; must be at least 32 bits. */
+
+ /* Sum up all 16-bit words. */
+
+ pU16 = (SK_U16 *) pData;
+ for (Checksum = 0; Length > 1; Length -= 2) {
+ Checksum += *pU16++;
+ }
+
+ /* If this is an odd number of bytes, add-in the last byte. */
+
+ if (Length > 0) {
+#ifdef SK_BIG_ENDIAN
+ /* Add the last byte as the high byte. */
+ Checksum += ((unsigned) *(SK_U8 *) pU16) << 8;
+#else /* !SK_BIG_ENDIAN */
+ /* Add the last byte as the low byte. */
+ Checksum += *(SK_U8 *) pU16;
+#endif /* !SK_BIG_ENDIAN */
+ }
+
+ /* Add-in any carries. */
+
+ SKCS_OC_ADD(Checksum, Checksum, 0);
+
+ /* Add-in any new carry. */
+
+ SKCS_OC_ADD(Checksum, Checksum, 0);
+
+ /* Note: All bits beyond the 16-bit limit are now zero. */
+
+ return ((unsigned) Checksum);
+} /* SkCsCalculateChecksum */
+
+#endif /* SK_CS_CALCULATE_CHECKSUM */
+
+/******************************************************************************
+ *
+ * SkCsEvent - the CSUM event dispatcher
+ *
+ * Description:
+ * This is the event handler for the CSUM module.
+ *
+ * Arguments:
+ * pAc - Pointer to adapter context.
+ *
+ * Ioc - I/O context.
+ *
+ * Event - Event id.
+ *
+ * Param - Event dependent parameter.
+ *
+ * Returns:
+ * The 16-bit Internet Checksum for the specified data.
+ *
+ * Note: The checksum is calculated in the machine's natural byte order,
+ * i.e. little vs. big endian. Thus, the resulting checksum is different
+ * for the same input data on little and big endian machines.
+ *
+ * However, when written back to the network packet, the byte order is
+ * always in correct network order.
+ */
+int SkCsEvent(
+SK_AC *pAc, /* Pointer to adapter context. */
+SK_IOC Ioc, /* I/O context. */
+SK_U32 Event, /* Event id. */
+SK_EVPARA Param) /* Event dependent parameter. */
+{
+ int ProtoIndex;
+ int NetNumber;
+
+ switch (Event) {
+ /*
+ * Clear protocol statistics.
+ *
+ * Param - Protocol index, or -1 for all protocols.
+ * - Net number.
+ */
+ case SK_CSUM_EVENT_CLEAR_PROTO_STATS:
+
+ ProtoIndex = (int)Param.Para32[1];
+ NetNumber = (int)Param.Para32[0];
+ if (ProtoIndex < 0) { /* Clear for all protocols. */
+ if (NetNumber >= 0) {
+ SK_MEMSET(&pAc->Csum.ProtoStats[NetNumber][0], 0,
+ sizeof(pAc->Csum.ProtoStats[NetNumber]));
+ }
+ }
+ else { /* Clear for individual protocol. */
+ SK_MEMSET(&pAc->Csum.ProtoStats[NetNumber][ProtoIndex], 0,
+ sizeof(pAc->Csum.ProtoStats[NetNumber][ProtoIndex]));
+ }
+ break;
+ default:
+ break;
+ }
+ return (0); /* Success. */
+} /* SkCsEvent */
+
+#endif /* SK_USE_CSUM */