a92485b2c2 addrman: use unordered_map instead of map (Vasil Dimov)
Pull request description:
`CAddrMan` uses `std::map` internally even though it does not require
that the map's elements are sorted. `std::map`'s access time is
`O(log(map size))`. `std::unordered_map` is more suitable as it has a
`O(1)` access time.
This patch lowers the execution times of `CAddrMan`'s methods as follows
(as per `src/bench/addrman.cpp`):
```
AddrMan::Add(): -3.5%
AddrMan::GetAddr(): -76%
AddrMan::Good(): -0.38%
AddrMan::Select(): -45%
```
ACKs for top commit:
jonatack:
ACK a92485b2c2
achow101:
ACK a92485b2c2
hebasto:
re-ACK a92485b2c2, only suggested changes and rebased since my [previous](https://github.com/bitcoin/bitcoin/pull/18722#pullrequestreview-666663681) review.
Tree-SHA512: d82959a00e6bd68a6c4c5a265dd08849e6602ac3231293b7a3a3b7bf82ab1d3ba77f8ca682919c15c5d601b13e468b8836fcf19595248116635f7a50d02ed603
`CAddrMan` uses `std::map` internally even though it does not require
that the map's elements are sorted. `std::map`'s access time is
`O(log(map size))`. `std::unordered_map` is more suitable as it has a
`O(1)` access time.
This patch lowers the execution times of `CAddrMan`'s methods as follows
(as per `src/bench/addrman.cpp`):
```
AddrMan::Add(): -3.5%
AddrMan::GetAddr(): -76%
AddrMan::Good(): -0.38%
AddrMan::Select(): -45%
```
CAddrMan.GetAddr() would previously limit the number and percentage of
addresses returned (to ADDRMAN_GETADDR_MAX (1000) and
ADDRMAN_GETADDR_MAX_PCT (23) respectively). Instead, make it the callers
responsibility to specify the maximum addresses and percentage they want
returned.
For net_processing, the maximums are MAX_ADDR_TO_SEND (1000) and
MAX_PCT_ADDR_TO_SEND (23). For rpc/net, the maximum is specified by the
client.
748977690e Add asmap_direct fuzzer that tests Interpreter directly (Pieter Wuille)
7cf97fda15 Make asmap Interpreter errors fatal and fuzz test it (Pieter Wuille)
c81aefc537 Add additional effiency checks to sanity checker (Pieter Wuille)
fffd8dca2d Add asmap sanity checker (Pieter Wuille)
5feefbe6e7 Improve asmap Interpret checks and document failures (Pieter Wuille)
2b3dbfa5a6 Deal with decoding failures explicitly in asmap Interpret (Pieter Wuille)
1479007a33 Introduce Instruction enum in asmap (Pieter Wuille)
Pull request description:
This improves/documents the failure cases inside the asmap interpreter. None of the changes are bug fixes (they only change behavior for corrupted asmap files), but they may make things easier to follow.
In a second step, a sanity checker is added that effectively executes every potential code path through the asmap file, checking the same failure cases as the interpreter, and more. It takes around 30 ms to run for me for a 1.2 MB asmap file.
I've verified that this accepts asmap files constructed by https://github.com/sipa/asmap/blob/master/buildmap.py with a large dataset, and no longer accepts it with 1 bit changed in it.
ACKs for top commit:
practicalswift:
ACK 748977690e modulo feedback below.
jonatack:
ACK 748977690e code review, regular build/tests/ran bitcoin with -asmap, fuzz build/ran both fuzzers overnight.
fjahr:
ACK 748977690e
Tree-SHA512: d876df3859735795c857c83e7155ba6851ce839bdfa10c18ce2698022cc493ce024b5578c1828e2a94bcdf2552c2f46c392a251ed086691b41959e62a6970821
- move asmap #includes to sorted positions in addrman and init (move-only)
- remove redundant quotes in asmap InitError, update test
- remove full stops from asmap logging to be consistent with debug logging,
update tests
3c1bc40205 Add extra logging of asmap use and bucketing (Gleb Naumenko)
e4658aa8ea Return mapped AS in RPC call getpeerinfo (Gleb Naumenko)
ec45646de9 Integrate ASN bucketing in Addrman and add tests (Gleb Naumenko)
8feb4e4b66 Add asmap utility which queries a mapping (Gleb Naumenko)
Pull request description:
This PR attempts to solve the problem explained in #16599.
A particular attack which encouraged us to work on this issue is explained here [[Erebus Attack against Bitcoin Peer-to-Peer Network](https://erebus-attack.comp.nus.edu.sg/)] (by @muoitranduc)
Instead of relying on /16 prefix to diversify the connections every node creates, we would instead rely on the (ip -> ASN) mapping, if this mapping is provided.
A .map file can be created by every user independently based on a router dump, or provided along with the Bitcoin release. Currently we use the python scripts written by @sipa to create a .map file, which is no larger than 2MB (awesome!).
Here I suggest adding a field to peers.dat which would represent a hash of asmap file used while serializing addrman (or 0 for /16 prefix legacy approach).
In this case, every time the file is updated (or grouping method changed), all buckets will be re-computed.
I believe that alternative selective re-bucketing for only updated ranges would require substantial changes.
TODO:
- ~~more unit tests~~
- ~~find a way to test the code without including >1 MB mapping file in the repo.~~
- find a way to check that mapping file is not corrupted (checksum?)
- comments and separate tests for asmap.cpp
- make python code for .map generation public
- figure out asmap distribution (?)
~Interesting corner case: I’m using std::hash to compute a fingerprint of asmap, and std::hash returns size_t. I guess if a user updates the OS to 64-bit, then the hash of asap will change? Does it even matter?~
ACKs for top commit:
laanwj:
re-ACK 3c1bc40205
jamesob:
ACK 3c1bc40205 ([`jamesob/ackr/16702.3.naumenkogs.p2p_supplying_and_using`](https://github.com/jamesob/bitcoin/tree/ackr/16702.3.naumenkogs.p2p_supplying_and_using))
jonatack:
ACK 3c1bc40205
Tree-SHA512: e2dc6171188d5cdc2ab2c022fa49ed73a14a0acb8ae4c5ffa970172a0365942a249ad3d57e5fb134bc156a3492662c983f74bd21e78d316629dcadf71576800c
Instead of using /16 netgroups to bucket nodes in Addrman for connection
diversification, ASN, which better represents an actor in terms
of network-layer infrastructure, is used.
For testing, asmap.raw is used. It represents a minimal
asmap needed for testing purposes.
After 40 minutes, time out a test-before-evict entry and just evict without
testing. Otherwise, if we were unable to test an entry for some reason, we
might break using feelers altogether.
Changes addrman to use the test-before-evict discipline in which an
address is to be evicted from the tried table is first tested and if
it is still online it is not evicted.
Adds tests to provide test coverage for this change.
This change was suggested as Countermeasure 3 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.
6eddd43 Fix warnings when building with DEBUG_ADDRMAN (practicalswift)
Pull request description:
Fix warnings when building with `DEBUG_ADDRMAN`.
Warnings prior to this commit:
```
addrman.cpp:390:24: warning: comparison of integers of different signs: 'size_type' (aka 'unsigned long') and 'int' [-Wsign-compare]
if (vRandom.size() != nTried + nNew)
~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~
addrman.cpp:411:52: warning: comparison of integers of different signs: 'int' and 'size_type' (aka 'unsigned long') [-Wsign-compare]
if (info.nRandomPos < 0 || info.nRandomPos >= vRandom.size() || vRandom[info.nRandomPos] != n)
~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~
addrman.cpp:419:25: warning: comparison of integers of different signs: 'size_type' (aka 'unsigned long') and 'int' [-Wsign-compare]
if (setTried.size() != nTried)
~~~~~~~~~~~~~~~ ^ ~~~~~~
addrman.cpp:421:23: warning: comparison of integers of different signs: 'size_type' (aka 'unsigned long') and 'int' [-Wsign-compare]
if (mapNew.size() != nNew)
~~~~~~~~~~~~~ ^ ~~~~
4 warnings generated.
```
Tree-SHA512: 0316faecfe95066d2c9a0b6b3960086e43824f21a67086a895ea45fbce1327f8d6df5945fe923c2dbe4efce430bc1384d515d317c3930d97d24965e507cf734d
680bc2cbb Use range-based for loops (C++11) when looping over map elements (practicalswift)
Pull request description:
Before this commit:
```c++
for (std::map<T1, T2>::iterator x = y.begin(); x != y.end(); ++x) {
T1 z = (*x).first;
…
}
```
After this commit:
```c++
for (auto& x : y) {
T1 z = x.first;
…
}
```
Tree-SHA512: 954b136b7f5e6df09f39248a6b530fd9baa9ab59d7c2c7eb369fd4afbb591b7a52c92ee25f87f1745f47b41d6828b7abfd395b43daf84a55b4e6a3d45015e3a0
Warnings prior to this commit:
```
addrman.cpp:390:24: warning: comparison of integers of different signs: 'size_type' (aka 'unsigned long') and 'int' [-Wsign-compare]
if (vRandom.size() != nTried + nNew)
~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~
addrman.cpp:411:52: warning: comparison of integers of different signs: 'int' and 'size_type' (aka 'unsigned long') [-Wsign-compare]
if (info.nRandomPos < 0 || info.nRandomPos >= vRandom.size() || vRandom[info.nRandomPos] != n)
~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~
addrman.cpp:419:25: warning: comparison of integers of different signs: 'size_type' (aka 'unsigned long') and 'int' [-Wsign-compare]
if (setTried.size() != nTried)
~~~~~~~~~~~~~~~ ^ ~~~~~~
addrman.cpp:421:23: warning: comparison of integers of different signs: 'size_type' (aka 'unsigned long') and 'int' [-Wsign-compare]
if (mapNew.size() != nNew)
~~~~~~~~~~~~~ ^ ~~~~
4 warnings generated.
```
This changes the logging categories to boolean flags instead of strings.
This simplifies the acceptance testing by avoiding accessing a scoped
static thread local pointer to a thread local set of strings. It
eliminates the only use of boost::thread_specific_ptr outside of
lockorder debugging.
This change allows log entries to be directed to multiple categories
and makes it easy to change the logging flags at runtime (e.g. via
an RPC, though that isn't done by this commit.)
It also eliminates the fDebug global.
Configuration of unknown logging categories now produces a warning.
There are only a few uses of `insecure_random` outside the tests.
This PR replaces uses of insecure_random (and its accompanying global
state) in the core code with an FastRandomContext that is automatically
seeded on creation.
This is meant to be used for inner loops. The FastRandomContext
can be in the outer scope, or the class itself, then rand32() is used
inside the loop. Useful e.g. for pushing addresses in CNode or the fee
rounding, or randomization for coin selection.
As a context is created per purpose, thus it gets rid of
cross-thread unprotected shared usage of a single set of globals, this
should also get rid of the potential race conditions.
- I'd say TxMempool::check is not called enough to warrant using a special
fast random context, this is switched to GetRand() (open for
discussion...)
- The use of `insecure_rand` in ConnectThroughProxy has been replaced by
an atomic integer counter. The only goal here is to have a different
credentials pair for each connection to go on a different Tor circuit,
it does not need to be random nor unpredictable.
- To avoid having a FastRandomContext on every CNode, the context is
passed into PushAddress as appropriate.
There remains an insecure_random for test usage in `test_random.h`.
If a node is offline failed outbound connection attempts will crank up
the addrman counter and effectively blow away our state.
This change reduces the problem by only counting attempts made while
the node believes it has outbound connections to at least two
netgroups.
Connect and addnode connections are also not counted, as there is no
reason to unequally penalize them for their more frequent
connections -- though there should be no real effect from this
unless their addnode configureation is later removed.
Wasteful repeated connection attempts while only a few connections are
up are avoided via nLastTry.
This is still somewhat incomplete protection because our outbound
peers could be down but not timed out or might all be on 'local'
networks (although the requirement for multiple netgroups helps).
Adds several unittests for CAddrMan and CAddrInfo.
Increases the accuracy of addrman tests.
Removes non-determinism in tests by overriding the random number generator.
Extracts testing code from addrman class to test class.
