doc: What do dsa, dssu, dsq, dsi, dsf, dss, dsc, inv, and dstx stand for?

[coolaj86]

The ds prefix of each stands for "Dark Send", from the good ol days. If it were renamed, these would all be ps* (Private Send) or cj* (CoinJoin).

See https://docs.dash.org/projects/core/en/stable/docs/guide/dash-features-coinjoin.html#coinjoin-processing

Index + Direction	Message	Meaning
1 ➡️	version	Begin MasterNode Handshake
1 ↩️	version sendaddr2	-
1 ➡️	verack	-
1 ↩️	verack mnauth	Version is acceptable + MN Proof
* ↩️	sendheaders sendcmpct senddsq	Negotiate desired messages & sub-protocols
* ➡️	senddsq	REQUIRED Opt-in to receiving dsq messages
* ↩️	ping	Begin ping/pong keepalive
* ↩️	inv	Inventory (transactions, blocks) either incoming messages, or response to getblocks or mempool
2 ➡️	dsa	DarkSend (Please) Allow
2 ↩️	dssu dsq	DarkSend (Accpeted into) Queue Note: you won't get the dsq reply to your dsa unless you've sent senddsq
3 ➡️	dsi	DarkSend 1 (Ready Bit set to True)
4 ↩️	dssu dsf dssu	DarkSend Final Draft (Unsigned)
5 ➡️	dss	DarkSend Signed Transaction (one from each participant)
6 ↩️	dsc inv	DarkSend Complete dstx inventory
7 🌎	dstx	DarkSend Transaction (the randomly selected tx is broadcast)
-	getdata	Query memory pool for current dstx
* ↩️	dssu + *	DarkSend Status Update

See also:

• https://docs.dash.org/projects/core/en/stable/docs/reference/p2p-network-control-messages.html
• https://docs.dash.org/projects/core/en/stable/docs/guide/dash-features-coinjoin.html#coinjoin-processing
• https://docs.dash.org/projects/core/en/stable/docs/reference/p2p-network-privatesend-messages.html