Block diagram
Protocol body represents particular payload on transport level (OSI layer 4).
Typically this payload in encapsulated into network level (OSI layer 3) packet, which includes "protocol number" field that would be used to decide what's inside the payload and how to parse it. Thanks to IANA's standardization effort, multiple network level use the same IDs for these payloads named "protocol numbers".
This is effectively a "router" type: it expects to get protocol number as a parameter, and then invokes relevant type parser based on that parameter.
This page hosts a formal specification of protocol_body using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.
meta:
id: protocol_body
license: CC0-1.0
ks-version: 0.8
imports:
- /network/tcp_segment
- /network/icmp_packet
- /network/udp_datagram
- /network/ipv4_packet
- /network/ipv6_packet
doc: |
Protocol body represents particular payload on transport level (OSI
layer 4).
Typically this payload in encapsulated into network level (OSI layer
3) packet, which includes "protocol number" field that would be used
to decide what's inside the payload and how to parse it. Thanks to
IANA's standardization effort, multiple network level use the same
IDs for these payloads named "protocol numbers".
This is effectively a "router" type: it expects to get protocol
number as a parameter, and then invokes relevant type parser based
on that parameter.
doc-ref: https://www.iana.org/assignments/protocol-numbers/protocol-numbers.xhtml
params:
- id: protocol_num
type: u1
doc: Protocol number as an integer.
seq:
- id: body
type:
switch-on: protocol
cases:
'protocol_enum::hopopt': option_hop_by_hop
'protocol_enum::tcp': tcp_segment
'protocol_enum::icmp': icmp_packet
'protocol_enum::udp': udp_datagram
'protocol_enum::ipv4': ipv4_packet
'protocol_enum::ipv6': ipv6_packet
'protocol_enum::ipv6_nonxt': no_next_header
instances:
protocol:
value: protocol_num
enum: protocol_enum
types:
no_next_header:
doc: Dummy type for IPv6 "no next header" type, which signifies end of headers chain.
option_hop_by_hop:
seq:
- id: next_header_type
type: u1
- id: hdr_ext_len
type: u1
- id: body
size: 'hdr_ext_len > 0 ? hdr_ext_len - 1 : 1'
- id: next_header
type: protocol_body(next_header_type)
enums:
protocol_enum:
0: hopopt
1: icmp
2: igmp
3: ggp
4: ipv4
5: st
6: tcp
7: cbt
8: egp
9: igp
10: bbn_rcc_mon
11: nvp_ii
12: pup
13: argus
14: emcon
15: xnet
16: chaos
17: udp
18: mux
19: dcn_meas
20: hmp
21: prm
22: xns_idp
23: trunk_1
24: trunk_2
25: leaf_1
26: leaf_2
27: rdp
28: irtp
29: iso_tp4
30: netblt
31: mfe_nsp
32: merit_inp
33: dccp
34: x_3pc
35: idpr
36: xtp
37: ddp
38: idpr_cmtp
39: tp_plus_plus
40: il
41: ipv6
42: sdrp
43: ipv6_route
44: ipv6_frag
45: idrp
46: rsvp
47: gre
48: dsr
49: bna
50: esp
51: ah
52: i_nlsp
53: swipe
54: narp
55: mobile
56: tlsp
57: skip
58: ipv6_icmp
59: ipv6_nonxt
60: ipv6_opts
61: any_host_internal_protocol
62: cftp
63: any_local_network
64: sat_expak
65: kryptolan
66: rvd
67: ippc
68: any_distributed_file_system
69: sat_mon
70: visa
71: ipcv
72: cpnx
73: cphb
74: wsn
75: pvp
76: br_sat_mon
77: sun_nd
78: wb_mon
79: wb_expak
80: iso_ip
81: vmtp
82: secure_vmtp
83: vines
84: ttp_or_iptm
85: nsfnet_igp
86: dgp
87: tcf
88: eigrp
89: ospfigp
90: sprite_rpc
91: larp
92: mtp
93: ax_25
94: ipip
95: micp
96: scc_sp
97: etherip
98: encap
99: any_private_encryption_scheme
100: gmtp
101: ifmp
102: pnni
103: pim
104: aris
105: scps
106: qnx
107: a_n
108: ipcomp
109: snp
110: compaq_peer
111: ipx_in_ip
112: vrrp
113: pgm
114: any_0_hop
115: l2tp
116: ddx
117: iatp
118: stp
119: srp
120: uti
121: smp
122: sm
123: ptp
124: isis_over_ipv4
125: fire
126: crtp
127: crudp
128: sscopmce
129: iplt
130: sps
131: pipe
132: sctp
133: fc
134: rsvp_e2e_ignore
135: mobility_header
136: udplite
137: mpls_in_ip
138: manet
139: hip
140: shim6
141: wesp
142: rohc
255: reserved_255