How do I use SSDP?

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I need a way for my application to find someone with the same application on a local network.

But can't find the docs to use a protocol like SSPD. It says its UDP on port 1900 and the ip 239.255.255.250.

It also says it can use NOTIFY and M-SEARCH.

But that is it. I've hit a wall. And I need some guidence.

OVERVIEW

Trying to make my apps automatically find each other and exchange ip/names on a local network so they can talk to each other p2p-style without a connection broker.

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p2pssdplocal-network
Seriously, first result when you use google with SSPD protocol. – Marcus Müller
What do you mean first result? I get a wikipage. – guestedForAnwser
yes, indeed, and that gives you plenty of links, pointers, words to google for, including the IETF draft defining that protocol. – Marcus Müller
I know this isn't easy, really! But still, it's a complex standard, and you will have to read the draft to understand the draft to know what you're doing; I don't think anyone can offer you a shortcut for that. – Marcus Müller
I did not ask for shortcuts nor anwsers. But guidance. Like "read this article" or "lookup this (term)" or "try these apps out, it might not be the experience you're looking for" or "SSDP is wildy insecure, look into (w/e) instead". – guestedForAnwser

1 Answers

2
votes

The UPnP Device Architecture reference contains the de-facto SSDP reference: it's very similar to the IETF spec and has dozens of well tested implementations already. Chapter 1 contains everything needed to implement SSDP, assuming you know how to send and receive multicast and unicast UDP messages.

My advice on implementing SSDP: Don't. It may look simple but there are a lot of gotchas on the way. Find a library or service that does SSDP for you. If you are on linux I suggest GSSDP (reference, code) (but I'm a bit biased having worked on it). I would assume other platforms have similar libraries.