Ip4Option.c revision 4fd606d1f5abe38e1f42c38de1d2e895166bd0f4
/** @file
IP4 option support functions.
Copyright (c) 2005 - 2011, Intel Corporation. All rights reserved.<BR>
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
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include "Ip4Impl.h"
/**
Validate the IP4 option format for both the packets we received
and will transmit.
@param[in] Option The first byte of the option
@param[in] OptionLen The length of the whole option
@param[in] Rcvd The option is from the packet we received if TRUE,
otherwise the option we wants to transmit.
@retval TRUE The option is properly formatted
@retval FALSE The option is mal-formated
**/
)
{
Cur = 0;
case IP4_OPTION_NOP:
Cur++;
break;
case IP4_OPTION_EOP:
break;
case IP4_OPTION_LSRR:
case IP4_OPTION_SSRR:
case IP4_OPTION_RR:
//
//
return FALSE;
}
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.
//
return FALSE;
}
break;
default:
return FALSE;
}
break;
}
}
return TRUE;
}
/**
Copy the option from the original option to buffer. It
handles the details such as:
fragments.
2. Pad the options copied over to aligned to 4 bytes.
@param[in] Option The original option to copy from
@param[in] OptionLen The length of the original option
@param[in] FirstFragment Whether it is the first fragment
@param[in, out] Buf The buffer to copy options to. NULL
@param[in, out] BufLen The length of the buffer
@retval EFI_SUCCESS The options are copied over
@retval EFI_BUFFER_TOO_SMALL Buf is NULL or BufLen provided is too small.
**/
)
{
Cur = 0;
Next = 0;
if (Type == IP4_OPTION_NOP) {
//
// Keep the padding, in case that the sender wants to align
// the option, say, to 4 bytes
//
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
//
}
}
}
//
// 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) {
Next++;
}
//
// Head length is in the unit of 4 bytes. Now, Len is the
// acutal option length to appear in the IP header.
//
//
// If the buffer is too small, set the BufLen then return
//
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.
//
return EFI_SUCCESS;
}