MdeModulePkg: Replace BSD License with BSD+Patent License

[mirror_edk2.git] / MdeModulePkg / Universal / Network / Ip4Dxe / Ip4Option.c

/** @file\r
  IP4 option support functions.\r
\r
Copyright (c) 2005 - 2018, Intel Corporation. All rights reserved.<BR>\r
SPDX-License-Identifier: BSD-2-Clause-Patent\r
\r
**/\r
\r
#include "Ip4Impl.h"\r
\r
\r
/**\r
  Validate the IP4 option format for both the packets we received\r
  and will transmit.\r
\r
  @param[in]  Option            The first byte of the option\r
  @param[in]  OptionLen         The length of the whole option\r
  @param[in]  Rcvd              The option is from the packet we received if TRUE,\r
                                otherwise the option we wants to transmit.\r
\r
  @retval TRUE     The option is properly formatted\r
  @retval FALSE    The option is mal-formated\r
\r
**/\r
BOOLEAN\r
Ip4OptionIsValid (\r
  IN UINT8                  *Option,\r
  IN UINT32                 OptionLen,\r
  IN BOOLEAN                Rcvd\r
  )\r
{\r
  UINT32                    Cur;\r
  UINT32                    Len;\r
  UINT32                    Point;\r
\r
  Cur       = 0;\r
\r
  while (Cur < OptionLen) {\r
    switch (Option[Cur]) {\r
    case IP4_OPTION_NOP:\r
      Cur++;\r
      break;\r
\r
    case IP4_OPTION_EOP:\r
      Cur = OptionLen;\r
      break;\r
\r
    case IP4_OPTION_LSRR:\r
    case IP4_OPTION_SSRR:\r
    case IP4_OPTION_RR:\r
      Len   = Option[Cur + 1];\r
      Point = Option[Cur + 2];\r
\r
      //\r
      // SRR/RR options are formatted as |Type|Len|Point|Ip1|Ip2|...\r
      //\r
      if ((OptionLen - Cur < Len) || (Len < 3) || ((Len - 3) % 4 != 0)) {\r
        return FALSE;\r
      }\r
\r
      if ((Point > Len + 1) || (Point % 4 != 0)) {\r
        return FALSE;\r
      }\r
\r
      //\r
      // The Point must point pass the last entry if the packet is received\r
      // by us. It must point to 4 if the packet is to be sent by us for\r
      // source route option.\r
      //\r
      if ((Option[Cur] != IP4_OPTION_RR) &&\r
          ((Rcvd && (Point != Len + 1)) || (!Rcvd && (Point != 4)))) {\r
\r
        return FALSE;\r
      }\r
\r
      Cur += Len;\r
      break;\r
\r
    default:\r
      Len = Option[Cur + 1];\r
\r
      if ((OptionLen - Cur < Len) || (Len < 2)) {\r
        return FALSE;\r
      }\r
\r
      Cur = Cur + Len;\r
      break;\r
    }\r
\r
  }\r
\r
  return TRUE;\r
}\r
\r
\r
/**\r
  Copy the option from the original option to buffer. It\r
  handles the details such as:\r
  1. whether copy the single IP4 option to the first/non-first\r
     fragments.\r
  2. Pad the options copied over to aligned to 4 bytes.\r
\r
  @param[in]       Option            The original option to copy from\r
  @param[in]       OptionLen         The length of the original option\r
  @param[in]       FirstFragment     Whether it is the first fragment\r
  @param[in, out]  Buf               The buffer to copy options to. NULL\r
  @param[in, out]  BufLen            The length of the buffer\r
\r
  @retval EFI_SUCCESS           The options are copied over\r
  @retval EFI_BUFFER_TOO_SMALL  Buf is NULL or BufLen provided is too small.\r
\r
**/\r
EFI_STATUS\r
Ip4CopyOption (\r
  IN     UINT8              *Option,\r
  IN     UINT32             OptionLen,\r
  IN     BOOLEAN            FirstFragment,\r
  IN OUT UINT8              *Buf,           OPTIONAL\r
  IN OUT UINT32             *BufLen\r
  )\r
{\r
  UINT8                     OptBuf[40];\r
  UINT32                    Cur;\r
  UINT32                    Next;\r
  UINT8                     Type;\r
  UINT32                    Len;\r
\r
  ASSERT ((BufLen != NULL) && (OptionLen <= 40));\r
\r
  Cur   = 0;\r
  Next  = 0;\r
\r
  while (Cur < OptionLen) {\r
    Type  = Option[Cur];\r
    Len   = Option[Cur + 1];\r
\r
    if (Type == IP4_OPTION_NOP) {\r
      //\r
      // Keep the padding, in case that the sender wants to align\r
      // the option, say, to 4 bytes\r
      //\r
      OptBuf[Next] = IP4_OPTION_NOP;\r
      Next++;\r
      Cur++;\r
\r
    } else if (Type == IP4_OPTION_EOP) {\r
      //\r
      // Don't append the EOP to avoid including only a EOP option\r
      //\r
      break;\r
\r
    } else {\r
      //\r
      // don't copy options that is only valid for the first fragment\r
      //\r
      if (FirstFragment || (Type & IP4_OPTION_COPY_MASK) != 0) {\r
        CopyMem (OptBuf + Next, Option + Cur, Len);\r
        Next += Len;\r
      }\r
\r
      Cur += Len;\r
    }\r
  }\r
\r
  //\r
  // Don't append an EOP only option.\r
  //\r
  if (Next == 0) {\r
    *BufLen = 0;\r
    return EFI_SUCCESS;\r
  }\r
\r
  //\r
  // Append an EOP if the end of option doesn't coincide with the\r
  // end of the IP header, that is, isn't aligned to 4 bytes..\r
  //\r
  if ((Next % 4) != 0) {\r
    OptBuf[Next] = IP4_OPTION_EOP;\r
    Next++;\r
  }\r
\r
  //\r
  // Head length is in the unit of 4 bytes. Now, Len is the\r
  // acutal option length to appear in the IP header.\r
  //\r
  Len = ((Next + 3) &~0x03);\r
\r
  //\r
  // If the buffer is too small, set the BufLen then return\r
  //\r
  if ((Buf == NULL) || (*BufLen < Len)) {\r
    *BufLen = Len;\r
    return EFI_BUFFER_TOO_SMALL;\r
  }\r
\r
  //\r
  // Copy the option to the Buf, zero the buffer first to pad\r
  // the options with NOP to align to 4 bytes.\r
  //\r
  ZeroMem (Buf, Len);\r
  CopyMem (Buf, OptBuf, Next);\r
  *BufLen = Len;\r
  return EFI_SUCCESS;\r
}\r