SDP support for <proto> udp

[vanrein]

• As per RFC 8866, without rtpmap and possibly with fmtp
• This example shows [unregistered] media type application/vnd.wireguard
• Wireshark does not like the fmtp: line -- that would be a bug there

v=0
o=- 3280287138 1947228850 IN IP6 2001:db8:12::34
s=-
c=IN IP6 2001:db8:12::34
t=0 0
m=application 9638 udp vnd.wireguard
a=fmtp:vnd.wireguard pubkey=z7otO6+NKCOM/I7gq6mvcVqYyX3u27Z0WVKMY/juel8=
a=sendrecv

[vanrein]

Style consistency makes sense, I agree. Very difficult to do when the fingers think they know what to type :)

[vanrein]

The re approach of standards compliance really pays off, I think. Thank you. I needed only this small change to do something that takes the standards to a rare corner, namely to negotatiate Wireguard tunnels. SDP support for UDP can exchange its endpoints, but also its keying material. Works like a charm. Not finished, but the code, config and man-page are already quite decent.

[sreimers]

Thanks!