mirror of
https://github.com/bitcoin/bips.git
synced 2024-11-19 01:40:05 +01:00
159 lines
4.6 KiB
Plaintext
159 lines
4.6 KiB
Plaintext
<pre>
|
|
BIP: 61
|
|
Layer: Peer Services
|
|
Title: Reject P2P message
|
|
Author: Gavin Andresen <gavinandresen@gmail.com>
|
|
Comments-Summary: Controversial; some recommendation, and some discouragement
|
|
Comments-URI: https://github.com/bitcoin/bips/wiki/Comments:BIP-0061
|
|
Status: Final
|
|
Type: Standards Track
|
|
Created: 2014-06-18
|
|
</pre>
|
|
|
|
==Abstract==
|
|
|
|
This BIP describes a new message type for the Bitcoin peer-to-peer network.
|
|
|
|
==Motivation==
|
|
|
|
Giving peers feedback about why their blocks or transactions are rejected, or
|
|
why they are being banned for not following the protocol helps
|
|
interoperability between different implementations.
|
|
|
|
It also gives SPV (simplified payment verification) clients a hint that something
|
|
may be wrong when their transactions are rejected due to insufficient priority
|
|
or fees.
|
|
|
|
==Specification==
|
|
|
|
Data types in this specification are as described at https://en.bitcoin.it/wiki/Protocol_specification
|
|
|
|
===reject===
|
|
|
|
One new message type "reject" is introduced. It is sent directly to a peer in response to a "version", "tx" or "block" message.
|
|
|
|
For example, the message flow between two peers for a relayed transaction that is rejected for some reason would be:
|
|
|
|
--> inv
|
|
<-- getdata
|
|
--> tx
|
|
<-- reject
|
|
|
|
All implementations of the P2P protocol version 70,002 and later should support the reject message.
|
|
|
|
====common payload====
|
|
|
|
|
|
Every reject message begins with the following fields. Some messages append extra, message-specific data.
|
|
|
|
{|
|
|
| Field Size || Name || Data type || Comments
|
|
|-
|
|
| variable || response-to-msg || var_str || Message that triggered the reject
|
|
|-
|
|
| 1 || reject-code || uint8_t || 0x01 through 0x4f (see below)
|
|
|-
|
|
| variable || reason || var_string || Human-readable message for debugging
|
|
|}
|
|
|
|
The human-readable string is intended only for debugging purposes; in particular, different implementations may
|
|
use different strings. The string should not be shown to users or used for anthing besides diagnosing
|
|
interoperability problems.
|
|
|
|
The following reject code categories are used; in the descriptions below, "server" is the peer generating
|
|
the reject message, "client" is the peer that will receive the message.
|
|
|
|
{|
|
|
| Range || Category
|
|
|-
|
|
| 0x01-0x0f || Protocol syntax errors
|
|
|-
|
|
| 0x10-0x1f || Protocol semantic errors
|
|
|-
|
|
| 0x40-0x4f || Server policy rule
|
|
|}
|
|
|
|
==== rejection codes common to all message types ====
|
|
|
|
{|
|
|
| Code || Description
|
|
|-
|
|
| 0x01 || Message could not be decoded
|
|
|}
|
|
|
|
==== reject version codes ====
|
|
|
|
Codes generated during the initial connection process in response to a "version" message:
|
|
|
|
{|
|
|
| Code || Description
|
|
|-
|
|
| 0x11 || Client is an obsolete, unsupported version
|
|
|-
|
|
| 0x12 || Duplicate version message received
|
|
|}
|
|
|
|
==== reject tx payload, codes ====
|
|
|
|
Transaction rejection messages extend the basic message with the transaction id hash:
|
|
|
|
{|
|
|
| Field Size || Name || Data type || Comments
|
|
|-
|
|
| 32 || hash || char[32] || transaction that is rejected
|
|
|}
|
|
|
|
The following codes are used:
|
|
|
|
{|
|
|
| Code || Description
|
|
|-
|
|
| 0x10 || Transaction is invalid for some reason (invalid signature, output value greater than input, etc.)
|
|
|-
|
|
| 0x12 || An input is already spent
|
|
|-
|
|
| 0x40 || Not mined/relayed because it is "non-standard" (type or version unknown by the server)
|
|
|-
|
|
| 0x41 || One or more output amounts are below the 'dust' threshold
|
|
|-
|
|
| 0x42 || Transaction does not have enough fee/priority to be relayed or mined
|
|
|}
|
|
|
|
==== payload, reject block ====
|
|
|
|
Block rejection messages extend the basic message with the block header hash:
|
|
|
|
{|
|
|
| Field Size || Name || Data type || Comments
|
|
|-
|
|
| 32 || hash || char[32] || block (hash of block header) that is rejected
|
|
|}
|
|
|
|
Rejection codes:
|
|
|
|
{|
|
|
| code || description
|
|
|-
|
|
| 0x10 || Block is invalid for some reason (invalid proof-of-work, invalid signature, etc)
|
|
|-
|
|
| 0x11 || Block's version is no longer supported
|
|
|-
|
|
| 0x43 || Inconsistent with a compiled-in checkpoint
|
|
|}
|
|
|
|
Note: blocks that are not part of the server's idea of the current best chain, but are otherwise valid, should not trigger reject messages.
|
|
|
|
== Compatibility ==
|
|
|
|
The reject message is backwards-compatible; older peers that do not recognize the reject message will ignore it.
|
|
|
|
== Implementation notes ==
|
|
|
|
Implementors must consider what happens if an attacker either sends them
|
|
reject messages for valid transactions/blocks or sends them random
|
|
reject messages, and should beware of possible denial-of-service attacks.
|
|
For example, notifying the user of every reject message received
|
|
would make it trivial for an attacker to mount an annoy-the-user attack.
|
|
Even merely writing every reject message to a debugging log could make
|
|
an implementation vulnerable to a fill-up-the-users-disk attack.
|