[Bitcoin-development] Missing fRelayTxes in version message

Turkey Breast turkeybreast at yahoo.com
Wed Jun 19 10:33:13 UTC 2013


It's a problem if you work with iterators to deserialize the byte stream. Even failing that, it's just sloppy programming. What happens in the future when new fields are added to the version message? It's not a big deal to say that this protocol version has X number of fields, that (higher) protocol version message has X + N number of fields. Deterministic number of fields per protocol version is sensical and how Bitcoin has been for a long time.

And yes, it was a problem for me that caused a lot of confusion why this byte didn't exist in many version messages despite the standard saying it should and the code in bitcoind indicating it should. Nowhere was this written. It doesn't help other implementations to have an unclear behaviour that depends on some magic from one implementation.



________________________________
 From: Mike Hearn <mike at plan99.net>
To: Turkey Breast <turkeybreast at yahoo.com> 
Cc: "bitcoin-development at lists.sourceforge.net" <bitcoin-development at lists.sourceforge.net> 
Sent: Wednesday, June 19, 2013 11:39 AM
Subject: Re: [Bitcoin-development] Missing fRelayTxes in version message
 


It has to be optional because old clients don't send it, obviously.

Why is this even an issue? There's no problem with variable length messages in any codebase that I'm aware of. Is this solving some actual problem?



On Wed, Jun 19, 2013 at 12:30 AM, Turkey Breast <turkeybreast at yahoo.com> wrote:

That's me. I never said to make all messages fixed length. I said to make a fixed number of fields per protocol. So given a protocol version number, you know the number of fields in a message. This is not only easier for parsing messages, but just good practice. I don't see why a 1 byte flag needs to be optional anyway.
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>________________________________
> From: Mike Hearn <mike at plan99.net>
>To: Turkey Breast <turkeybreast at yahoo.com> 
>Cc: Bitcoin Dev <bitcoin-development at lists.sourceforge.net> 
>Sent: Tuesday, June 18, 2013 9:48 PM
>Subject: Re: [Bitcoin-development] Missing fRelayTxes in version message
> 
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>It's not a bug (although there was recently a change to make bitcoind/qt always send this field anyway). 
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>I don't know where Amir is going with BIP 60. Version messages have always been variable length. There's nothing inherent in the Bitcoin protocol that says all messages are fixed length, indeed, tx messages are allowed to have arbitrary data appended after them that gets relayed.
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>On Tue, Jun 18, 2013 at 7:45 PM, Turkey Breast <turkeybreast at yahoo.com> wrote:
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>See this BIP. I'm not sure if this is a bug or what, but it would be good if messages always had a fixed number of fields per protocol version.
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>>https://en.bitcoin.it/wiki/BIP_0060#Code_Updates
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>>This BIP details everything that needs to be done and proposes a protocol upgrade.
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