/** @file To validate, parse and process the DHCP options. Copyright (c) 2006 - 2016, 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. **/ #ifndef __EFI_DHCP4_OPTION_H__ #define __EFI_DHCP4_OPTION_H__ /// /// DHCP option tags (types) /// #define DHCP_OPTION_MAGIC 0x63538263 // Network byte order #define DHCP_MAX_OPTIONS 256 // // DHCP option types, this is used to validate the DHCP options. // #define DHCP_OPTION_SWITCH 1 #define DHCP_OPTION_INT8 2 #define DHCP_OPTION_INT16 3 #define DHCP_OPTION_INT32 4 #define DHCP_OPTION_IP 5 #define DHCP_OPTION_IPPAIR 6 // // Value of DHCP overload option // #define DHCP_OVERLOAD_FILENAME 1 #define DHCP_OVERLOAD_SVRNAME 2 #define DHCP_OVERLOAD_BOTH 3 /// /// The DHCP option structure. This structure extends the EFI_DHCP_OPTION /// structure to support options longer than 255 bytes, such as classless route. /// typedef struct { UINT8 Tag; UINT16 Len; UINT8 *Data; } DHCP_OPTION; /// /// Structures used to parse the DHCP options with RFC3396 support. /// typedef struct { UINT8 Index; UINT16 Offset; } DHCP_OPTION_COUNT; typedef struct { DHCP_OPTION_COUNT *OpCount; DHCP_OPTION *Options; UINT8 *Buf; } DHCP_OPTION_CONTEXT; /// /// The options that matters to DHCP driver itself. The user of /// DHCP clients may be interested in other options, such as /// classless route, who can parse the DHCP offer to get them. /// typedef struct { IP4_ADDR NetMask; // DHCP4_TAG_NETMASK IP4_ADDR Router; // DHCP4_TAG_ROUTER, only the first router is used // // DHCP specific options // UINT8 DhcpType; // DHCP4_TAG_MSG_TYPE UINT8 Overload; // DHCP4_TAG_OVERLOAD IP4_ADDR ServerId; // DHCP4_TAG_SERVER_ID UINT32 Lease; // DHCP4_TAG_LEASE UINT32 T1; // DHCP4_TAG_T1 UINT32 T2; // DHCP4_TAG_T2 } DHCP_PARAMETER; /// /// Structure used to describe and validate the format of DHCP options. /// Type is the options' data type, such as DHCP_OPTION_INT8. MinOccur /// is the minium occurance of this data type. MaxOccur is defined /// similarly. If MaxOccur is -1, it means that there is no limit on the /// maximum occurance. Alert tells whether DHCP client should further /// inspect the option to parse DHCP_PARAMETER. /// typedef struct { UINT8 Tag; INTN Type; INTN MinOccur; INTN MaxOccur; BOOLEAN Alert; } DHCP_OPTION_FORMAT; typedef EFI_STATUS (*DHCP_CHECK_OPTION) ( IN UINT8 Tag, IN UINT8 Len, IN UINT8 *Data, IN VOID *Context ); /** Iterate through a DHCP message to visit each option. First inspect all the options in the OPTION field. Then if overloaded, inspect the options in FILENAME and SERVERNAME fields. One option may be encoded in several places. See RFC 3396 Encoding Long Options in DHCP @param[in] Packet The DHCP packet to check the options for @param[in] Check The callback function to be called for each option found @param[in] Context The opaque parameter for Check @retval EFI_SUCCESS The DHCP packet's options are well formated @retval EFI_INVALID_PARAMETER The DHCP packet's options are not well formated **/ EFI_STATUS DhcpIterateOptions ( IN EFI_DHCP4_PACKET *Packet, IN DHCP_CHECK_OPTION Check OPTIONAL, IN VOID *Context ); /** Validate the packet's options. If necessary, allocate and fill in the interested parameters. @param[in] Packet The packet to validate the options @param[out] Para The variable to save the DHCP parameters. @retval EFI_OUT_OF_RESOURCES Failed to allocate memory to validate the packet. @retval EFI_INVALID_PARAMETER The options are mal-formated @retval EFI_SUCCESS The options are parsed into OptionPoint **/ EFI_STATUS DhcpValidateOptions ( IN EFI_DHCP4_PACKET *Packet, OUT DHCP_PARAMETER **Para OPTIONAL ); /** Parse the options of a DHCP packet. It supports RFC 3396: Encoding Long Options in DHCP. That is, it will combine all the option value of all the occurances of each option. A little bit of implemenation: It adopts the "Key indexed counting" algorithm. First, it allocates an array of 256 DHCP_OPTION_COUNTs because DHCP option tag is encoded as a UINT8. It then iterates the DHCP packet to get data length of each option by calling DhcpIterOptions with DhcpGetOptionLen. Now, it knows the number of present options and their length. It allocates a array of DHCP_OPTION and a continuous buffer after the array to put all the options' data. Each option's data is pointed to by the Data field in DHCP_OPTION structure. At last, it call DhcpIterateOptions with DhcpFillOption to fill each option's data to its position in the buffer. @param[in] Packet The DHCP packet to parse the options @param[out] Count The number of valid dhcp options present in the packet @param[out] OptionPoint The array that contains the DHCP options. Caller should free it. @retval EFI_NOT_FOUND Cannot find any option. @retval EFI_OUT_OF_RESOURCES Failed to allocate memory to parse the packet. @retval EFI_INVALID_PARAMETER The options are mal-formated @retval EFI_SUCCESS The options are parsed into OptionPoint **/ EFI_STATUS DhcpParseOption ( IN EFI_DHCP4_PACKET *Packet, OUT INTN *Count, OUT DHCP_OPTION **OptionPoint ); /** Append an option to the memory, if the option is longer than 255 bytes, splits it into several options. @param[out] Buf The buffer to append the option to @param[in] Tag The option's tag @param[in] DataLen The length of the option's data @param[in] Data The option's data @return The position to append the next option **/ UINT8 * DhcpAppendOption ( OUT UINT8 *Buf, IN UINT8 Tag, IN UINT16 DataLen, IN UINT8 *Data ); /** Build a new DHCP packet from a seed packet. Options may be deleted or appended. The caller should free the NewPacket when finished using it. @param[in] SeedPacket The seed packet to start with @param[in] DeleteCount The number of options to delete @param[in] DeleteList The options to delete from the packet @param[in] AppendCount The number of options to append @param[in] AppendList The options to append to the packet @param[out] NewPacket The new packet, allocated and built by this function. @retval EFI_OUT_OF_RESOURCES Failed to allocate memory @retval EFI_INVALID_PARAMETER The options in SeekPacket are mal-formated @retval EFI_SUCCESS The packet is build. **/ EFI_STATUS DhcpBuild ( IN EFI_DHCP4_PACKET *SeedPacket, IN UINT32 DeleteCount, IN UINT8 *DeleteList OPTIONAL, IN UINT32 AppendCount, IN EFI_DHCP4_PACKET_OPTION *AppendList[] OPTIONAL, OUT EFI_DHCP4_PACKET **NewPacket ); #endif