fix noise 2

[Fi3]

• Remove 2 bytes header from hanshake messages
• Split noise payload in 65Kb chunks

[Sjors]

Thanks, I'll wait for your second todo item.

[Sjors]

I'm not sure if you already rebased, but try the following to get rid of my commits in the PR:

# assuming 1 commit from you
git rebase HEAD~1 --onto Sjors/2023/11/sv2-poll

[Sjors]

I changed a few things before merging:

• std::span -> Span (see src/span.h, though this might change again with the move to c++20)
• added a constant INITIATOR_EXPECTED_HANDSHAKE_MESSAGE_LENGTH = 170

I tested against your stratum branch stratum-mining/stratum@dev...Fi3:stratum-1:UpdateNoise though only on my custom signet, which generally doesn't have long messages.

I'll test on mainnet later.

I guess I should run an inscription tool to get >65KB messages on signet :-)

I also plan to add some more length check asserts, and rename SendMsg in noise.h to WriteMsg, to prevent confusion between creating the message and actually sending it.

[Sjors]

Changes squashed into 945838fca264c8469e24d629a4552741dbbd4dda and 945838fca264c8469e24d629a4552741dbbd4dda.

Can you take a look at key_tests.cpp, as this now fails with memory access violation at address: 0x1: no mapping at fault address around line 35. Not sure if that's because of the changes here or because of my rebase. I'll also take a look later.

[Fi3]

To tested it on testnet, with jdc you get pretty long messages. Also to test it I change the max noise chunk size to smaller value like 120 bytes and it worked.