6eecba475e net_processing: make MaybePunishNodeFor{Block,Tx} return void (Pieter Wuille)
ae60d485da net_processing: remove Misbehavior score and increments (Pieter Wuille)
6457c31197 net_processing: make all Misbehaving increments = 100 (Pieter Wuille)
5120ab1478 net_processing: drop 8 headers threshold for incoming BIP130 (Pieter Wuille)
944c54290d net_processing: drop Misbehavior for unconnecting headers (Pieter Wuille)
9f66ac7cf1 net_processing: do not treat non-connecting headers as response (Pieter Wuille)
Pull request description:
So far, discouragement of peers triggers when their misbehavior score exceeds 100 points. Most types of misbehavior increment the score by 100, triggering immediate discouragement, but some types do not. This PR makes all increments equal to either 100 (meaning any misbehavior will immediately cause disconnection and discouragement) or 0 (making the behavior effectively unconditionally allowed), and then removes the logic for score accumulation.
This simplifies the code a bit, but also makes protocol expectations clearer: if a peer misbehaves, they get disconnected. There is no good reason why certain types of protocol violations should be permitted 4 times (howmuch=20) or 9 times (howmuch=10), while many others are never allowed. Furthermore, the distinction between these looks arbitrary.
The specific types of misbehavior that are changed to 100 are:
* Sending us a `block` which does not connect to our header tree (which necessarily must have been unsollicited). [used to be score 10]
* Sending us a `headers` with a non-continuous headers sequence. [used to be score 20]
* Sending us more than 1000 addresses in a single `addr` or `addrv2` message [used to be score 20]
* Sending us more than 50000 invs in a single `inv` message [used to be score 20]
* Sending us more than 2000 headers in a single `headers` message [used to be score 20]
The specific types of misbehavior that are changed to 0 are:
* Sending us 10 (*) separate BIP130 headers announcements that do not connect to our block tree [used to be score 20]
* Sending us more than 8 headers in a single `headers` message (which thus does not get treated as a BIP130 announcement) that does not connect to our block tree. [used to be score 10]
I believe that none of these behaviors are unavoidable, except for the one marked (*) which can in theory happen still due to interaction between BIP130 and variations in system clocks (the max 2 hour in the future rule). This one has been removed entirely. In order to remove the impact of the bug it was designed to deal with, without relying on misbehavior, a separate improvement is included that makes `getheaders`-tracking more accurate.
In another unrelated improvement, this also gets rid of the 8 header limit heuristic to determine whether an incoming non-connecting `headers` is a potential BIP130 announcement, as this rule is no longer needed to prevent spurious Misbehavior. Instead, any non-connecting `headers` is now treated as a potential announcement.
ACKs for top commit:
sr-gi:
ACK [6eecba4](6eecba475e)
achow101:
ACK 6eecba475e
mzumsande:
Code Review ACK 6eecba475e
glozow:
light code review / concept ACK 6eecba475e
Tree-SHA512: e11e8a652c4ec048d8961086110a3594feefbb821e13f45c14ef81016377be0db44b5311751ef635d6e026def1960aff33f644e78ece11cfb54f2b7daa96f946
In order to ensure that the change of nVersion to a uint32_t in the
previous commit has no effect, rename nVersion to version in this commit
so that reviewers can easily spot if a spot was missed or if there is a
check somewhere whose semantics have changed.
This removes the need to actually track misbehavior score (see further commit), because any
Misbehaving node will immediately hit the discouragement threshold.
