adding icmp data format

data-formats/df-010-icmp.md

@@ -0,0 +1,109 @@
+# ICMP Data Format
+
+This document describes the keys with `test_keys` that all experiments
+using ICMP SHOULD populate, possibly using directly the specific template
+code. See this directory's [README](README.md) for the basic concepts.
+
+| Name       | `icmp` |
+|------------|--------|
+| Version    | 0      |
+
+## Specification
+
+```JSON
+{
+    "messages": []
+}
+```
+
+- `messages` (`[] Message`): list of message objects. See below.
+
+## Message
+
+```Javascript
+{
+    "timeout": "no",
+    "connected": "no",
+    "error": "no",
+    "source_ip": "1.2.3.4",
+    "type": 0,
+    "code": 0,
+    "quote": {},
+    "t0": 1785153856079
+    "t": 1785153856080
+}
+```
+
+- `timeout` (`string`): string describing whether the TTL-limited probe timed out without receiving an ICMP message in response
+
+- `connected` (`string`): string describing whether the TTL-limited probe successfully connected to the destination IP address of the probe
+
+- `error` (`string`): string describing any errors that occur on the socket
+
+- `source_ip` (`string`): the source IP address of the ICMP message
+
+- `type` (`int`): the type of the ICMP message
+
+- `code` (`int`): the code of the ICMP message
+
+- `quote` (`Quote`): object describing the IP header and subsequent 8 bytes of the original packet
+
+- `t0` (`float64`): the time when the TTL-limited probe is sent, represented in terms of the UNIX epoch
+
+- `t` (`float64`): the time when the ICMP message triggered via the TTL-limited probe is received, represented in terms of the UNIX epoch
+
+## Quote
+
+```Javascript
+{
+    "source_ip": "1.2.3.4",
+    "destination_ip": "5.6.7.8",
+    "protocol": "tcp",
+    "source_port": 7342,
+    "destination_port": 80,
+    "tcp_sequence_number": 123456789,
+    "udp_length": null,
+    "udp_checksum": null
+}
+```
+
+- `source_ip` (`string`): the source IP address of the original quoted packet
+
+- `destination_ip` (`string`): the destination IP address of the original quoted packet
+
+- `protocol` (`string`): the protocol of the original quoted packet
+
+- `source_port` (`int`): the source port of the original quoted packet
+
+- `destination_port` (`int`): the destination port of the original quoted packet
+
+- `tcp_sequence_number` (`int`): the TCP sequence number of the original quoted packet, if the protocol is tcp
+
+- `udp_length` (`int`): the length of the original quoted packet, if the protocol is udp
+
+- `udp_checksum` (`int`): the checksum of the original quoted packet, if the protocol is udp
+
+## Example
+
+In the following example we've omitted all the keys that are not relevant to the ICMP data format:
+
+```JSON
+{
+    "timeout": "no",
+    "connected": "",
+    "error": "",
+    "source_ip": "148.113.176.252",
+    "type": 11,
+    "code": 0,
+    "quote": {
+        "protocol": 6,
+        "source_port": 46828,
+        "destination_port": 443,
+        "tcp_sequence_number": 2972880068,
+        "udp_length": 0,
+        "udp_checksum": 0
+    },
+    "t0": 1785236311439,
+    "t": 1785236311439
+}
+```