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/** @file
Copyright (c) 2005 - 2006, Intel Corporation
All rights reserved. This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
Module Name:
Ip4Option.c
Abstract:
IP4 option support functions
**/
#include "Ip4Impl.h"
/**
Validate the IP4 option format for both the packets we received
and will transmit. It will compute the ICMP error message fields
if the option is mal-formated. But this information isn't used.
@param Option The first byte of the option
@param OptionLen The length of the whole option
@param Rcvd The option is from the packet we received if TRUE,
otherwise the option we wants to transmit.
@return TRUE: The option is properly formated
@return FALSE: The option is mal-formated
**/
BOOLEAN
Ip4OptionIsValid (
IN UINT8 *Option,
IN UINT32 OptionLen,
IN BOOLEAN Rcvd
)
{
UINT32 Cur;
UINT32 Len;
UINT32 Point;
volatile UINT8 IcmpType;
volatile UINT8 IcmpCode;
volatile UINT32 IcmpPoint;
IcmpType = ICMP_PARAMETER_PROBLEM;
IcmpCode = 0;
IcmpPoint = 0;
Cur = 0;
while (Cur < OptionLen) {
switch (Option[Cur]) {
case IP4_OPTION_NOP:
Cur++;
break;
case IP4_OPTION_EOP:
Cur = OptionLen;
break;
case IP4_OPTION_LSRR:
case IP4_OPTION_SSRR:
case IP4_OPTION_RR:
Len = Option[Cur + 1];
Point = Option[Cur + 2];
//
// SRR/RR options are formated as |Type|Len|Point|Ip1|Ip2|...
//
if ((OptionLen - Cur < Len) || (Len < 3) || ((Len - 3) % 4 != 0)) {
IcmpPoint = Cur + 1;
return FALSE;
}
if ((Point > Len + 1) || (Point % 4 != 0)) {
IcmpPoint = Cur + 2;
return FALSE;
}
//
// The Point must point pass the last entry if the packet is received
// by us. It must point to 4 if the packet is to be sent by us for
// source route option.
//
if ((Option[Cur] != IP4_OPTION_RR) &&
((Rcvd && (Point != Len + 1)) || (!Rcvd && (Point != 4)))) {
IcmpType = ICMP_DEST_UNREACHABLE;
IcmpCode = ICMP_SOURCEROUTE_FAILED;
return FALSE;
}
Cur += Len;
break;
default:
Len = Option[Cur + 1];
if ((OptionLen - Cur < Len) || (Len < 2)) {
IcmpPoint = Cur + 1;
return FALSE;
}
Cur = Cur + Len;
break;
}
}
return TRUE;
}
/**
Copy the option from the original option to buffer. It
handles the details such as:
1. whether copy the single IP4 option to the first/non-first
fragments.
2. Pad the options copied over to aligened to 4 bytes.
@param Option The original option to copy from
@param OptionLen The length of the original option
@param FirstFragment Whether it is the first fragment
@param Buf The buffer to copy options to
@param BufLen The length of the buffer
@retval EFI_SUCCESS The options are copied over
@retval EFI_BUFFER_TOO_SMALL The buffer caller provided is too small.
**/
EFI_STATUS
Ip4CopyOption (
IN UINT8 *Option,
IN UINT32 OptionLen,
IN BOOLEAN FirstFragment,
IN UINT8 *Buf, OPTIONAL
IN OUT UINT32 *BufLen
)
{
UINT8 OptBuf[40];
UINT32 Cur;
UINT32 Next;
UINT8 Type;
UINT32 Len;
ASSERT ((BufLen != NULL) && (OptionLen <= 40));
Cur = 0;
Next = 0;
while (Cur < OptionLen) {
Type = Option[Cur];
Len = Option[Cur + 1];
if (Type == IP4_OPTION_NOP) {
//
// Keep the padding, in case that the sender wants to align
// the option, say, to 4 bytes
//
OptBuf[Next] = IP4_OPTION_NOP;
Next++;
Cur++;
} else if (Type == IP4_OPTION_EOP) {
//
// Don't append the EOP to avoid including only a EOP option
//
break;
} else {
//
// don't copy options that is only valid for the first fragment
//
if (FirstFragment || (Type & IP4_OPTION_COPY_MASK)) {
CopyMem (OptBuf + Next, Option + Cur, Len);
Next += Len;
}
Cur += Len;
}
}
//
// Don't append an EOP only option.
//
if (Next == 0) {
*BufLen = 0;
return EFI_SUCCESS;
}
//
// Append an EOP if the end of option doesn't coincide with the
// end of the IP header, that is, isn't aligned to 4 bytes..
//
if ((Next % 4) != 0) {
OptBuf[Next] = IP4_OPTION_EOP;
Next++;
}
//
// Head length is in the unit of 4 bytes. Now, Len is the
// acutal option length to appear in the IP header.
//
Len = ((Next + 3) &~0x03);
//
// If the buffer is too small, set the BufLen then return
//
if ((Buf == NULL) || (*BufLen < Len)) {
*BufLen = Len;
return EFI_BUFFER_TOO_SMALL;
}
//
// Copy the option to the Buf, zero the buffer first to pad
// the options with NOP to align to 4 bytes.
//
ZeroMem (Buf, Len);
CopyMem (Buf, OptBuf, Next);
*BufLen = Len;
return EFI_SUCCESS;
}
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