On hosts that had spent some time with a failed internet connection their
nAttempts penalty was going through the roof (e.g. thousands for all peers)
and as a result the connect search was pegging the CPU and failing to get
more than a 4 connections after days of running (because it was taking so
long per try).
This change was suggested as Countermeasure 2 in
Eclipse Attacks on Bitcoin’s Peer-to-Peer Network, Ethan Heilman,
Alison Kendler, Aviv Zohar, Sharon Goldberg. ePrint Archive Report
2015/263. March 2015.
This change was suggested as Countermeasure 2 in
Eclipse Attacks on Bitcoin’s Peer-to-Peer Network, Ethan Heilman,
Alison Kendler, Aviv Zohar, Sharon Goldberg. ePrint Archive Report
2015/263. March 2015.
Give each address a single fixed location in the new and tried tables,
which become simple fixed-size arrays instead of sets and vectors.
This prevents attackers from having an advantages by inserting an
address multiple times.
This change was suggested as Countermeasure 1 in
Eclipse Attacks on Bitcoin’s Peer-to-Peer Network, Ethan Heilman,
Alison Kendler, Aviv Zohar, Sharon Goldberg. ePrint Archive Report
2015/263. March 2015.
It is also more efficient.
After the tinyformat switch sprintf() family functions support passing
actual std::string objects.
Remove unnecessary c_str calls (236 of them) in logging and formatting.
The function Get64(.) has a bug in case the width is not divisible by 64.
Since it is only ever used as Get64(0) this simply changes it to this
special case. Additionally, an assert is added, and a cast to prevent
a compiler error.
Use misc methods of avoiding unnecesary header includes.
Replace int typedefs with int##_t from stdint.h.
Replace PRI64[xdu] with PRI[xdu]64 from inttypes.h.
Normalize QT_VERSION ifs where possible.
Resolve some indirect dependencies as direct ones.
Remove extern declarations from .cpp files.
A function returned the element to remove from a bucket, instead of its
position in that bucket. This function was only called when a tried
bucket overflowed, which only happens after many outgoing connections
have been made.
Closes: #1065, #1156
This commit removes the dependency of serialize.h on PROTOCOL_VERSION,
and makes this parameter required instead of implicit. This is much saner,
as it makes the places where changing a version number can have an
influence obvious.
Design goals:
* Only keep a limited number of addresses around, so that addr.dat does not grow without bound.
* Keep the address tables in-memory, and occasionally write the table to addr.dat.
* Make sure no (localized) attacker can fill the entire table with his nodes/addresses.
See comments in addrman.h for more detailed information.
EthanHeilman