Packet Builder Language
=======================
:author: hhaim
:email: <hhaim@cisco.com>
:revnumber: 0.04
:quotes.++:
:numbered:

== change log

[options="header",cols="^1,^h,a"]
|=================
| Version |  name   |  meaning
| 0.01    |  hhaim |
- first version
| 0.02    | hhaim
|
- change the bool fields to properties
- add external/internal  property
- add const property  ( instead cant_change)
- change  TLV property - now learn the prev header
- add choice of next protocol that is not base on a field ( TCP->IP->TCP)
| 0.03    | ybrustin
|
- add MAC address regexp
- add gui_representation class with data_type, form_type, combobox_values, data_type_regexp items to describe GUI view of field
- rename choice attribute to value_based_next_header
- fixed some typos
| 0.04    | ybrustin
|
- change value_based_next_header, combobox_values (to be consistent with value_based_next_header) to dictionary
- added value_based_next_class for options
- move 'help' attribute to gui_representation
- add link to headers.yaml (references at bottom of the page)

|=================


== A file format for GUI packet builder

=== Introduction

We would like a file that will be read by GUI and will give us the ability to build packets using GUI

The format should be *YAML*


=== High Level Requirement

* Define a YAML object format for dynamic building of packets and a program that change various fields
* Ability to *parse* back the same buffer that was created using this tool (reversibility)
** Ability to load packet from a pcap file and parse it
* Ability to save the packet to a pcap file
* Ability to save the packet and program in JSON format (same JSON-RPC format)
* Set a value for any field of any protocol
* Vary packet fields across packets at run time e.g. changing IP/MAC addresses
* Stack protocols in any arbitrary order define in YAML format

=== Header that should be supported (first phase)

==== L2

* Ethernet
* 802.3
* LLC SNAP
* VLAN (with QinQ) stack
* MPLS stack

==== L3

* ARP
* IPv4
* IPv6 (4x header)
* IP-in-IP a.k.a IP Tunnelling (6over4, 4over6, 4over4, 6over6)

==== L4

* TCP
* UDP
* ICMPv4
* ICMPv6
* IGMP

==== L7  anchor:Payload[]

* Any text based protocol (HTTP, SIP, RTSP, NNTP etc.)
** random string
** repeat string

* Pattern Binary
** repeat of value (e.g 0x55)
** random
** seq (1,2,3,3,4)
** User Hex Dump editor


=== YAML Format

==== Header section

.Default Types  anchor:Types[]
[options="header",cols="1,2,3"]
|=================
| Field Name        |   meaning                                        | size in bits
| bit               |  describe the header object e.g tcp              |  1
| uint8             |  describe the header object e.g tcp              |  8
| uint16            |  the name in the GUI                             |  16
| uint32            |  sub fields of this header                       |  32
| uint64            |  sub fields of this header                       |  64
| other class type  | name of other class. for example, "c-mac-addr"; take fields from there, optionally overload them later  | The size taken from that class
| Payload           |     xref:Payload[Payload]                        | total packet size - all header until now
| vlen_t            | in case of varible size header this include the size to the end of varible size header see example xref:IpvOption[Ipv4Option] |total size of the object
|=================


.Default Data_Type anchor:Data_Type[]
[options="header",cols="1,2"]
|=================
| Field Name               | meaning
| none                     |  use Hex Editor as Types
| ipv4_t                   |  4 decimals 0-255 each
| mac_addr_t               |  ([0-9a-fA-F]\{2\}:)\{5\}[0-9a-fA-F]\{2\}
| ipv4_mask_t              |  should match uint32 type
| ipv6_t                   |  should have 16 bytes field size 8x16
| ipv6_mask_t              |  should have 16 bytes field size 8x16
| another header class     |  sub fields of this header
| char_t                   | array of bytes , look into the array_size of cost string
| var_char_t               | array based on a field value look into
| regexp_t                 |  define a Java function that converts a reg exp string to a buffer see here  xref:GenRegExp[RegExp]
|=================

.Default Form_Type anchor:Form_Type[]
[options="header",cols="1,3"]
|=================
| Field Name          |  meaning
| none                |  simple editing field
| combo_with_edit     |  combo box with predefined choices, can edit the field value manually
| combo_without_edit  |  combo box with predefined choices, can [underline]#not# edit the field value manually
| checkbox            |  toggle bits values, if item is array of bits, display several checkboxes per number of bits
|=================


.Default Gui_Representation anchor:Gui_Representation[]
[options="header",cols="1,^1,5,^1,10"]
|=================
| Field Name         | value type      | meaning                                            | Link                      | Additional info
| help               | string          | the name in the GUI                                |                           |
| data_type          | string          | how to represent data                              | xref:Data_Type[Data_Type] | data_type could get data_type_regexp e.g data_type = "ipv4"; data_type = "regexp" data_type_regexp = "string that define regexp and Java function"
| form_type          | string          | which editing form to use                          | xref:Form_Type[Form_Type] | for example for ip address use combobox with option to edit value manually or choose: key "localhost" value "127.0.0.1" etc.
| combobox_values    | dictionary      | pairs of 'key - value' for combo_with/without_edit |                           |
| data_type_regexp   | string          | in case it is reg_exp the name of the function     | xref:GenRegExp[GenRegExp] |
|=================


.Default Properties    anchor:Properties[]
[options="header",cols="1,7"]
|=================
| Field Name             | meaning
| ipv4_checksum          | auto calculates checksum on this header Ipv4 type
| tcp_checksum           | calculate TCP checksum
| udp_checksum           | calculate UDP checksum
| ipv4_total_length      | calculate ipv4 total length this pkt_size = header  + reset of packet
| tlv                    | TLV length of the header (inlcudes the prev field length) example ip-option, tcp-option
| le                     | little endian. deault is big
| const                  | const field for example the 4 version of ipv4 header - this GUI won't give option to change this field
| external               | marks the header as an external header for the GUI. for example IPv4 is external header and mac-addr is internal header ( compose external header)
|=================


.Field_Type  anchor:Field_Type[]
[options="header",cols="1,^1,30,^1,^1,30"]
|=================
| Field Name         | value type      |  meaning                                           | Default Value | Link | Example
| class              | string          | describe the class type                            |   in case class is defined no need to have name and vise versa           |      | class : tcp
| name               | string          | describe the instance name                         |   in case class is defined no need to have name and vise versa          |      | name : tcp
| array_size         | integer         | how many objects of this type, default value is 1  |  1            |      | array_size : 6 in case of mac-addr
| type               | string          | type, see  Types  define the size                  |   "uint8_t"   |  xref:Types[Types]   | type : "uint32_t" type : "mac_addr"
| gui_representation | dictionary      | description of how to view/edit data in GUI        |           | xref:Gui_Representation[Gui_Representation] | xref:Gui_Representation_Example[Gui_Representation_Example]
| default            | array/value     | default value in the packets , you can override value for subfields in parent see example
| [0 ]x header size  |   |    xref:Overide_Subfields_Example[Overide_Subfields_Example]
| properies          | array of string like masks
| properies of this fields             |  []        | xref:Properties[Properties] | ["le","external"] , ["tlv","le","const"]
| value_based_next_header              | dictionary |   define the next protocol based on a field value                    |  none         | xref:Value_Based_Next_Header[Value_Based_Next_Header]  |
| value_based_next_class               | dictionary |   define the next class based on a field value (useful for options)  |  none         | xref:Value_Based_Next_Class[Value_Based_Next_Class]  |
| next_headers       | string or type  |   a name of class that define the next or just an array                           |  "none"       | xref:Next_headers[Next_headers]  |
| fields             | array           | array of Field_Type                                                               |   []          |        | fields : [  ]
| offset             | integer/string  |   offset into the packet in bits, in case of auto add base of prev fields         |   "auto"      |        |
| option             | string          |   a java code that define a way to calculate varible size                         |   "none"      |        |  |
|=================


.Field_Type  anchor:ConstHeadesClass[]
[options="header",cols="^1,^10"]
|=================
| Field Name | value type
| "root"     | the root pointer to the start of blocks L2/802.3 etc
| "end"      | end TLV headers
| "payload"   | the rest of the packets as buffer/string etc
|=================


.Next_headers anchor:Next_headers[]
Example of Next_headers
[source,python]
----

 - class : "next-example-t-1"
   gui_representation:
       help : "next-example-t-1"
   next_headers : ["ipv4", "ipv6, "tcp"]

# option 1 define in the header itself
 - class : "tcp"
   gui_representation:
       help : "TCP header"
   properies : ["external"]
   next_headers : ["ipv4", "ipv6, "tcp"]
   fields :
        - name : "ver"

# option 2 define throw a class
 - class : "tcp"
   gui_representation:
       help : "TCP header"
   properies : ["external"]
   next_headers : "next-example-t-1" #
   fields :
        - name : "ver"
----


.Value_Based_Next_Header anchor:Value_Based_Next_Header[]
Example of value_based_next_header
[source,python]
----
        value_based_next_header:
            0x0800: 'ipv4'# name of an external or internal class , the GUI should distinct betwean internal and external
            0x0806: 'arp'
            0x86DD: 'ipv6'
            0x8100: 'vlan'
            0x8847: 'mpls unicast'
            default: 'payload' # if no match for any of above

----


.Generic RegExp Edit Field anchor:GenRegExp[]

This will define a regexp that match for user input and how to converts it to buffer of bytes

[source,python]
----

class MyClass : public RegExpBase {
  public:


  string get_reg_exp_string( ) {
    return ((\d){1-3})[.]((\d){1-3})[.]((\d){1-3})[.]((\d){1-3}))
  }

  # in case of match
  buffer get_buffer(){
     g= [get_group()[1].to_int()*256,get_group()[1].to_int()]
     # return list
     return (g)
  }

}

----



==== Relations between object headers

There would be a root object to point to possible starting headers


[source,python]
----

-  class : "root"
   gui_representation:
       help  : "Root"
   next_headers  : [ "ethernet", "llc", "_802-3"]
----

So in a way you could define a tree like this

[source,python]
----

root -> L2 (  Ethernet   , 802.3 , LLC SNAP  )
                |( by field )
                |
                  ------------------------------------- ( VLAN (with QinQ), MPLS , ipv4, ipv6,     ARP , ICMP )
                                                                                  |   |               |     |
                                                                                  |   ipv4/ipv6       -     -
                                                                                  |     |
                                                                                  |    |
  [Possibility - Ethernet/802.3/LLC SNAP)                                          |    UDP/TCP/Pyload
 Object                                                                            |     |
  for each option there tree of all the option                                      --- -
----


==== Rules

* The size of the header and offset is automatically defined in default by the order of the fields ( inc by type size multiply by array_size)
* It can be overrided by offset field ( put offset in the object ) and then an more advanced field can be shown earlier in the GUI
* The packet size is defined before the headers.  Header Should not be allowed to be added if the size + header size is bigger than packet size
* "Payload" is predefined Fields that take the reset of the packet and user can edit it ( see xref:Payload[Payload] )
* There would be a spare field in the Stream object so GUI could add more metadata for reconstructing the builder types
  for example in this example Ethrenet/IP/TCP/IP/TCP  you can't extrac from buffer alone that Payload is IP/TCP only the builder known that in build time.
* Ip total length need to keep the total_pkt_size - this ip header . this should work for internal header too.
* When GUI add header ("external") the total size of this header should be calculated ( varible size should be given a default - ipv4)


=== Examples


==== TLV (Ip option) anchor:IpvOption[], value_based_next_class anchor:Value_Based_Next_Class[]


IP-option see link:http://tools.ietf.org/html/rfc791[ip_option]

0 : END

1 : Length 1

other : Byte : Length ( +first) |option



[source,python]
----

 - class : "ip_option_131"
   gui_representation:
       help  : "ip_option"
   fields :
         - name : "length"    # tree with leaf of bits
           gui_representation:
               help : "length"
           type : uint8
           properties : ["tlv"] # the length include the prev field size (8 byte)

         - name : "pointer"    # tree with leaf of bits
           type : uint8

         - name : "buffer"    # tree with leaf of bits
           type : "tlv_reset"

 - class : "default_ip4_option_tlv"
   gui_representation:
       help  : "ip_option"
   fields :
         - name : "length"    # tree with leaf of bits
           gui_representation:
               help : "length"
           type : uint8
           properties : "tlv" # the length include the prev field size (8 byte)

         - name : "buffer"    # tree with leaf of bits
           type : "vlen_t"


 - class : "ip_option"
   gui_representation:
       help  : "ip_option"
   type : uint8
   default : [0x01]
   value_based_next_class :
       0x00  : "end"   # reserve name for ending the loop
       0x01  : "ip_option"   # back to this header
       0x131 : "ip_option_131"
       0x0812: "gre"
       default : "default_ip4_option_tlv"


----

* case of varible length field ip_option example



==== Example TCP/IP


[source,python]
----

 - class : "c-mac-addr"
   type : "uint8"
   array_size : 6
   default : [0x00, 0x00, 0x01, 0x00, 0x00, 0x00]
   gui_representation:
      data_type  : "mac-addr_t" # format ([0-9a-fA-F]{2}:){5}[0-9a-fA-F]{2}
      help  : "Mac addrees"


 - class : "ethernet"
   gui_representation:
       help : "Ethernet-L2"
   properties: ['external']
   fields :
        - name : "Dst"
          gui_representation:
              help : "destination mac"
          type : "c-mac-addr"

        - name : "Src"
          gui_representation:
              help : "source mac"
          type : "c-mac-addr"

        - name: "Ethertype"
          gui_representation:
              help: "Ethertype"
          type: "uint16"
          default: [0x0800]
          value_based_next_header :
                0x0800  : "ipv4"
                0x86DD  : "ipv6"
                0x8100  : "vlan"
                0x8847  : "mpls" #unicast
                default : "payload"


 - class : "ipv4"
   gui_representation:
       help : "Ipv4"
   fields :
        - name : "ver"
          gui_representation:
              help : "Version"
          type : "bit"
          array_size : 4
          default : [0, 1, 0, 0]
          properties : ["const"]

         - name : "ihl"
          type : "bit"
          array_size : 4
          default : [0, 1, 1, 1]
          properties : ["ipv4_ihl"]
          gui_representation:
              help : "IHL"
              form_type: "checkbox"

          ..

         - name : "hdr_chsum"
          gui_representation:
              help : "Header Checksum"
          default : [0x00,0x00]
          properties : ["ipv4_check_sum", "const"]

         - name : "total_len"
          gui_representation:
              help : "Total Length"
          default : [0x00,0x00]
          properties : ["ipv4_total_len", "const"] # auto calculate total_size-offset_header

         - name : "protocol"
          type : uint8
          default : 0x06
          value_based_next_header : &ipv4_next_header
               0x06  : "tcp"
               0x11  : "udp"
               0x29  : "ipv6"
               0x2F  : "gre"
               default : "payload"
          gui_representation:
              help : "IPv4 next Protocol"
              form_type: "combo_without_edit"
              combobox_values:
                <<: *ipv4_next_header # take same choices as value_based_next_header

         - name : "src_addr"
          type : uint32
          default : [16, 0, 0, 0]
          gui_representation:
              help : "Source Address"
              data_type  : "ipv4" # reserve

         - name : "dst_addr"
          default : [48, 0, 0, 0]
          type : uint32
          gui_representation:
              help : "Destination Address"
              data_type  : "ipv4" # reserve
              form_type : "combo_with_edit"
              combobox_values:
                    [127, 0, 0, 1]: 'localhost'
                    [255, 255, 255, 255]: 'broadcast'


 - class : "tcp"
   gui_representation:
       help : "TCP"
   properties : ["external"]
   fields :
         - name : "src_port"
          gui_representation:
              help : "Source Port"
          default : [0x30,0x00]
          type : uint16

         - name : "dest_port"
          gui_representation:
              help : "Source Port"
          default : [0x30,0x00]
          type : uint16

         - name : "seq"
          gui_representation:
              help : "Seq Number"
          type : uint32
          default : [0x30,0x00,00,00]

         - name : "ack"
          gui_representation:
              help : "Ack Number"
          type : uint32
          default : [0x30,0x00,00,00]

        ...

         - name : "flags"    # tree with leaf of bits
          gui_representation:
              help : "Ack Number"
          type : uint8
          default : [0x30]
          fields :
                 - name : "urg"
                  help : "URG"
                  type  : bit
                  default : [0x0]

                 - name : "ack"
                  help : "ACK"
                  type  : bit
                  default : [0x1]
                  ..

         - name : "checksum"
          gui_representation:
              help : "TCP Checksum"
          type : uint16
          default : [0x00,0x00]
          properties : ["tcp_checksum"] # auto calculate total_size-offset_header


-  class : "root" # reserve
   gui_representation:
       help  : "Root"
   next_headers : [ "ethrenet" ,"llc","_802-3"]
---------------------------


==== Overide subfields example anchor:Overide_Subfields_Example[]

In this example parent class default value overrides default values of sub-fields ( 2 different mac-addr)

[source,python]
----

 - class : "c-mac-addr"
   type : "uint8"
   array_size : 6
   gui_representation:
      help  : "Mac addrees"
      data_type  : "mac-addr_t" # format ([0-9a-fA-F]{2}:){5}[0-9a-fA-F]{2}
   default : [0x00,0x00,0x01,0x00,0x00,0x00]


 - class : "ethernet"
   gui_representation:
       help : "Ethernet-L2"
   properties : ["external"]
   default : [0x00,0x01,0x01,0x00,0x00,0x00, 0x00,0x02,0x02,0x00,0x00,0x00 ,0x08,00] # change the default of sub-fields . it is const size
   fields :
        - name : "Dst"
          gui_representation:
              help : "destination mac"
          type : "c-mac-addr"

        - name : "Src"
          gui_representation:
              help : "source mac"
          type : "c-mac-addr"

        - name : "ip_protocol"
          type : "uint16_t"
          default : [0x08,0x00]
          value_based_next_header :
                0x0800  : "ipv4"
                0x86DD  : "ipv6"
                0x8100  : "vlan"
                0x8847  : "mpls unicast"
                default : "payload"
----

==== Gui Representation example anchor:Gui_Representation_Example[]
[underline]#In YAML:#
[source,python]
----
  - name: 'Flags'
    type: 'bit'
    array_size: 3
    gui_representation:
        help: 'IPv4 Flags'
        form_type: 'checkbox' # can check each bit


  - name: 'dst_addr'
    default: [48, 0, 0, 0]
    type: uint32
    gui_representation:
        help: 'IPv4 Destination Address'
        data_type: 'ipv4_t' # special representation case, show as 4 decimal numbers
        form_type: 'combo_with_edit' # can choose from pre-defined values or edit manually
        combobox_values:
            [127, 0, 0, 1]: 'localhost'
            [255, 255, 255, 255]: 'broadcast'


  - name: 'protocol'
    type: uint8
    default: 0x06
    value_based_next_header: &ipv4_next_header
        0x06: 'tcp'
        0x11: 'udp'
        default : "payload"
    gui_representation:
        help: 'IPv4 Protocol Field'
        form_type: 'combo_without_edit' # choose from supported protocols, no manual edit
        combobox_values:
            <<: *ipv4_next_header # take same choices as value_based_next_header
----

[underline]#In GUI:#

checkbox for bits:

image:images/checkbox.jpg[]

editing in combo-box:

image:images/combo_button_editing.jpg[]

choosing from predefined values:

image:images/combo_button_choosing.jpg[]

==== Union base

TBD



=== Resource
*  link:yaml/headers.yaml[headers.yaml]
*  link:https://wireedit.com/[WireEdit]
*  link:http://ostinato.org/[ostinato]
*  link:http://www.slideshare.net/nlekh/ixiaexplorer[IxExplorer]


