This replaces the current benchmarking framework with nanobench [1], an
MIT licensed single-header benchmarking library, of which I am the
autor. This has in my opinion several advantages, especially on Linux:
* fast: Running all benchmarks takes ~6 seconds instead of 4m13s on
an Intel i7-8700 CPU @ 3.20GHz.
* accurate: I ran e.g. the benchmark for SipHash_32b 10 times and
calculate standard deviation / mean = coefficient of variation:
* 0.57% CV for old benchmarking framework
* 0.20% CV for nanobench
So the benchmark results with nanobench seem to vary less than with
the old framework.
* It automatically determines runtime based on clock precision, no need
to specify number of evaluations.
* measure instructions, cycles, branches, instructions per cycle,
branch misses (only Linux, when performance counters are available)
* output in markdown table format.
* Warn about unstable environment (frequency scaling, turbo, ...)
* For better profiling, it is possible to set the environment variable
NANOBENCH_ENDLESS to force endless running of a particular benchmark
without the need to recompile. This makes it to e.g. run "perf top"
and look at hotspots.
Here is an example copy & pasted from the terminal output:
| ns/byte | byte/s | err% | ins/byte | cyc/byte | IPC | bra/byte | miss% | total | benchmark
|--------------------:|--------------------:|--------:|----------------:|----------------:|-------:|---------------:|--------:|----------:|:----------
| 2.52 | 396,529,415.94 | 0.6% | 25.42 | 8.02 | 3.169 | 0.06 | 0.0% | 0.03 | `bench/crypto_hash.cpp RIPEMD160`
| 1.87 | 535,161,444.83 | 0.3% | 21.36 | 5.95 | 3.589 | 0.06 | 0.0% | 0.02 | `bench/crypto_hash.cpp SHA1`
| 3.22 | 310,344,174.79 | 1.1% | 36.80 | 10.22 | 3.601 | 0.09 | 0.0% | 0.04 | `bench/crypto_hash.cpp SHA256`
| 2.01 | 496,375,796.23 | 0.0% | 18.72 | 6.43 | 2.911 | 0.01 | 1.0% | 0.00 | `bench/crypto_hash.cpp SHA256D64_1024`
| 7.23 | 138,263,519.35 | 0.1% | 82.66 | 23.11 | 3.577 | 1.63 | 0.1% | 0.00 | `bench/crypto_hash.cpp SHA256_32b`
| 3.04 | 328,780,166.40 | 0.3% | 35.82 | 9.69 | 3.696 | 0.03 | 0.0% | 0.03 | `bench/crypto_hash.cpp SHA512`
[1] https://github.com/martinus/nanobench
* Adds support for asymptotes
This adds support to calculate asymptotic complexity of a benchmark.
This is similar to #17375, but currently only one asymptote is
supported, and I have added support in the benchmark `ComplexMemPool`
as an example.
Usage is e.g. like this:
```
./bench_bitcoin -filter=ComplexMemPool -asymptote=25,50,100,200,400,600,800
```
This runs the benchmark `ComplexMemPool` several times but with
different complexityN settings. The benchmark can extract that number
and use it accordingly. Here, it's used for `childTxs`. The output is
this:
| complexityN | ns/op | op/s | err% | ins/op | cyc/op | IPC | total | benchmark
|------------:|--------------------:|--------------------:|--------:|----------------:|----------------:|-------:|----------:|:----------
| 25 | 1,064,241.00 | 939.64 | 1.4% | 3,960,279.00 | 2,829,708.00 | 1.400 | 0.01 | `ComplexMemPool`
| 50 | 1,579,530.00 | 633.10 | 1.0% | 6,231,810.00 | 4,412,674.00 | 1.412 | 0.02 | `ComplexMemPool`
| 100 | 4,022,774.00 | 248.58 | 0.6% | 16,544,406.00 | 11,889,535.00 | 1.392 | 0.04 | `ComplexMemPool`
| 200 | 15,390,986.00 | 64.97 | 0.2% | 63,904,254.00 | 47,731,705.00 | 1.339 | 0.17 | `ComplexMemPool`
| 400 | 69,394,711.00 | 14.41 | 0.1% | 272,602,461.00 | 219,014,691.00 | 1.245 | 0.76 | `ComplexMemPool`
| 600 | 168,977,165.00 | 5.92 | 0.1% | 639,108,082.00 | 535,316,887.00 | 1.194 | 1.86 | `ComplexMemPool`
| 800 | 310,109,077.00 | 3.22 | 0.1% |1,149,134,246.00 | 984,620,812.00 | 1.167 | 3.41 | `ComplexMemPool`
| coefficient | err% | complexity
|--------------:|-------:|------------
| 4.78486e-07 | 4.5% | O(n^2)
| 6.38557e-10 | 21.7% | O(n^3)
| 3.42338e-05 | 38.0% | O(n log n)
| 0.000313914 | 46.9% | O(n)
| 0.0129823 | 114.4% | O(log n)
| 0.0815055 | 133.8% | O(1)
The best fitting curve is O(n^2), so the algorithm seems to scale
quadratic with `childTxs` in the range 25 to 800.
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
38e49ded8b tests: Add fuzzing harness for MessageSign, MessageVerify and other functions in util/message.h (practicalswift)
Pull request description:
Add fuzzing harness for `MessageSign`, `MessageVerify` and other functions in `util/message.h`.
See [`doc/fuzzing.md`](https://github.com/bitcoin/bitcoin/blob/master/doc/fuzzing.md) for information on how to fuzz Bitcoin Core. Don't forget to contribute any coverage increasing inputs you find to the [Bitcoin Core fuzzing corpus repo](https://github.com/bitcoin-core/qa-assets).
Happy fuzzing :)
ACKs for top commit:
vasild:
utACK 38e49ded8b
Tree-SHA512: 4f83718365d9c7e772a4ccecb31817bf17117efae2bfaf6e9618ff17908def0c8b97b5fa2504d51ab38b2e6f82c046178dd751495cc37ab4779c0b1ac1a4d211
48973402d8 wallet: Avoid use of Chain::Lock in CWallet::GetKeyBirthTimes (Russell Yanofsky)
e958ff9ab5 wallet: Avoid use of Chain::Lock in CWallet::CreateTransaction (Russell Yanofsky)
c0d07dc4cb wallet: Avoid use of Chain::Lock in CWallet::ScanForWalletTransactions (Russell Yanofsky)
1be8ff280c wallet: Avoid use of Chain::Lock in rescanblockchain (Russell Yanofsky)
3cb85ac594 wallet refactor: Avoid use of Chain::Lock in CWallet::RescanFromTime (Russell Yanofsky)
f7ba881bc6 wallet: Avoid use of Chain::Lock in listsinceblock (Russell Yanofsky)
bc96a9bfc6 wallet: Avoid use of Chain::Lock in importmulti (Russell Yanofsky)
25a9fcf9e5 wallet: Avoid use of Chain::Lock in importwallet and dumpwallet (Russell Yanofsky)
c1694ce6bb wallet: Avoid use of Chain::Lock in importprunedfunds (Russell Yanofsky)
ade5f87971 wallet refactor: Avoid use of Chain::Lock in qt wallettests (Russell Yanofsky)
f6da44ccce wallet: Avoid use of Chain::Lock in tryGetTxStatus and tryGetBalances (Russell Yanofsky)
bf30cd4922 refactor: Add interfaces::FoundBlock class to selectively return block data (Russell Yanofsky)
Pull request description:
This is a set of changes updating wallet code to make fewer calls to `Chain::Lock` methods, so the `Chain::Lock` class will be easier to remove in #16426 with fewer code changes and small changes to behavior.
ACKs for top commit:
MarcoFalke:
re-ACK 48973402d8, only change is fixing bug 📀
fjahr:
re-ACK 48973402d8, reviewed rebase and changes since last review, built and ran tests locally
ariard:
Coce Review ACK 4897340, only changes are one suggested by last review on more accurate variable naming, human-readable output, args comments in `findCommonAncestor`
Tree-SHA512: cfd2f559f976b6faaa032794c40c9659191d5597b013abcb6c7968d36b2abb2b14d4e596f8ed8b9a077e96522365261299a241a939b3111eaf729ba0c3ef519b
c9017ce3bc protect g_chainman with cs_main (James O'Beirne)
2b081c4568 test: add basic tests for ChainstateManager (James O'Beirne)
4ae29f5f0c use ChainstateManager to initialize chainstate (James O'Beirne)
5b690f0aae refactor: move RewindBlockIndex to CChainState (James O'Beirne)
89cdf4d569 validation: introduce unused ChainstateManager (James O'Beirne)
8e2ecfe249 validation: add CChainState.m_from_snapshot_blockhash (James O'Beirne)
Pull request description:
This is part of the [assumeutxo project](https://github.com/bitcoin/bitcoin/projects/11):
Parent PR: #15606
Issue: #15605
Specification: https://github.com/jamesob/assumeutxo-docs/tree/master/proposal
---
This changeset introduces `ChainstateManager`, which is responsible for creating and managing access to multiple chainstates. Until we allow chainstate creation from UTXO snapshots (next assumeutxo PR?) it's basically unnecessary, but it is a prerequisite for background IBD support.
Changes are also made to the initialization process to make use of `g_chainman` and thus clear the way for multiple chainstates being loaded on startup.
One immediate benefit of this change is that we no longer have the `g_blockman` global, but instead have the ChainstateManager inject a reference of its shared BlockManager into any chainstate it creates.
Another immediate benefit is that uses of `ChainActive()` and `ChainstateActive()` are now covered by lock annotations. Because use of `g_chainman` is annotated to require cs_main, these two functions subsequently follow.
Because of whitespace changes, this diff looks bigger than it is. E.g., 4813167d98 is most easily reviewed with
```sh
git show --color-moved=dimmed_zebra -w 4813167d98
```
ACKs for top commit:
MarcoFalke:
re-ACK c9017ce3bc📙
fjahr:
Code Review Re-ACK c9017ce3bc
ariard:
Code Review ACK c9017ce
ryanofsky:
Code review ACK c9017ce3bc. No changes since last review other than a straight rebase
Tree-SHA512: 3f250d0dc95d4bfd70852ef1e39e081a4a9b71a4453f276e6d474c2ae06ad6ae6a32b4173084fe499e1e9af72dd9007f4a8a375c63ce9ac472ffeaada41ab508
b1d24d1d03 Reorder the test instructions by number (Pieter Wuille)
c2ccadc26a Merge and generalize case 3 and case 6 (Pieter Wuille)
402ad5aaca Only run sanity check once at the end (Pieter Wuille)
eda8309bfc Assert immediately rather than caching failure (Pieter Wuille)
55608455cb Make a fuzzer-based copy of the prevector randomized test (Pieter Wuille)
Pull request description:
The current prevector test effectively randomly generates a number of operations to perform on a prevector and a normal vector, and checks consistency between the two.
By converting this into a fuzzer the operations can be targetted rather than random.
ACKs for top commit:
MarcoFalke:
ACK b1d24d1d03🍬
Tree-SHA512: 2b5c62abcd5fee94f42db03400531484d98c59e7f4308e0e683c61aabcd9ce42f85c5d058d2d5e7f8221124f71d2112b6a5f3c80e5d0fdae265a70647747e92f
cdfb8e7afa tests: Add fuzzing harness for HTTPRequest, libevent's evhttp and related functions (practicalswift)
Pull request description:
Add fuzzing harness for `HTTPRequest`, `libevent`'s `evhttp` and related functions.
ACKs for top commit:
laanwj:
ACK cdfb8e7afa
Tree-SHA512: da481afed5eb3232d3f3d0583094e56050e6234223dfcb356d8567fe0616336eb1b78c5e6821325fc9767e385e5dfaf3c96f0d35ffdb67f18d74f9a9a9464e24
283bd72156 tests: Add coverage of {,Incremental}DynamicUsage(const std::set<X, Y>& s) to existing fuzzer (practicalswift)
bf76000493 tests: Add fuzzing harness for classes/functions in cuckoocache.h (practicalswift)
57890b2555 tests: Add fuzzing harness for classes/functions in checkqueue.h (practicalswift)
2df5701e90 tests: Add coverage of GetVirtualTransactionSize(...) to existing fuzzer (practicalswift)
7b9a2dc864 tests: Add fuzzing harness for AdditionOverflow(...) (practicalswift)
44fb2a596b tests: Add fuzzing harness for FeeFilterRounder (practicalswift)
Pull request description:
Includes:
```
tests: Add fuzzing harness for FeeFilterRounder
tests: Add fuzzing harness for classes/functions in checkqueue.h
tests: Add fuzzing harness for classes/functions in cuckoocache.h
tests: Add coverage of {,Incremental}DynamicUsage(const std::set<X, Y>& s) to existing fuzzer
tests: Add coverage of GetVirtualTransactionSize(...) to existing fuzzer
tests: Add fuzzing harness for AdditionOverflow(...)
```
See [`doc/fuzzing.md`](https://github.com/bitcoin/bitcoin/blob/master/doc/fuzzing.md) for information on how to fuzz Bitcoin Core.
ACKs for top commit:
MarcoFalke:
ACK 283bd72156
Tree-SHA512: 2361edfb5c47741b22d9fb996836c5250c5a26bc5e956039ea6a0c55ba2d36c78f241d66f85bc02f5b85b9b83d5fde56a5c4702b9d1b7ac4a9a3ae391ca79eaa
9e071b0089 test: remove rapidcheck integration and tests (fanquake)
Pull request description:
Whilst the property tests are interesting, ultimately [rapidcheck](https://github.com/emil-e/rapidcheck) integration in this repository has not gained much traction. We have a limited number of tests, and they are rarely (if ever) run. Have discussed this with Chris Stewart.
ACKs for top commit:
practicalswift:
ACK 9e071b0089
Tree-SHA512: d0c12af3163382eee8413da420c63e39265a7b700709a05d518445832d45e049aed9508e32524db5228fe3ac114609a00b7bb890be047c07032e44a5ef4611e9
FoundBlock class allows interfaces::Chain::findBlock to return more block
information without having lots of optional output parameters. FoundBlock class
is also used by other chain methods in upcoming commits.
There is mostly no change in behavior. Only exception is
CWallet::RescanFromTime now throwing NonFatalCheckError instead of
std::logic_error.
9220a0fdd0 tests: Add one specialized ProcessMessage(...) fuzzing binary per message type for optimal results when using coverage-guided fuzzing (practicalswift)
fd1dae10b4 tests: Add fuzzing harness for ProcessMessage(...) (practicalswift)
Pull request description:
Add fuzzing harness for `ProcessMessage(...)`. Enables high-level fuzzing of the P2P layer.
All code paths reachable from this fuzzer can be assumed to be reachable for an untrusted peer.
Seeded from thin air (an empty corpus) this fuzzer reaches roughly 20 000 lines of code.
To test this PR:
```
$ make distclean
$ ./autogen.sh
$ CC=clang CXX=clang++ ./configure --enable-fuzz \
--with-sanitizers=address,fuzzer,undefined
$ make
$ src/test/fuzz/process_message
…
```
Worth noting about this fuzzing harness:
* To achieve a reasonable number of executions per seconds the state of the fuzzer is unfortunately not entirely reset between `test_one_input` calls. The set-up (`FuzzingSetup` ctor) and tear-down (`~FuzzingSetup`) work is simply too costly to be run on every iteration. There is a trade-off to handle here between a.) achieving high executions/second and b.) giving the fuzzer a totally blank slate for each call. Please let me know if you have any suggestion on how to improve this situation while maintaining >1000 executions/second.
* To achieve optimal results when using coverage-guided fuzzing I've chosen to create one specialised fuzzing binary per message type (`process_message_addr`, `process_message_block`, `process_message_blocktxn `, etc.) and one general fuzzing binary (`process_message`) which handles all messages types. The latter general fuzzer can be seeded with inputs generated by the former specialised fuzzers.
Happy fuzzing friends!
ACKs for top commit:
MarcoFalke:
ACK 9220a0fdd0🏊
Tree-SHA512: c314ef12b0db17b53cbf3abfb9ecc10ce420fb45b17c1db0b34cabe7c30e453947b3ae462020b0c9f30e2c67a7ef1df68826238687dc2479cd816f0addb530e5
9ff41f6419 tests: Add float to FUZZERS_MISSING_CORPORA (temporarily) (practicalswift)
8f6fb0a85a tests: Add serialization/deserialization fuzzing for integral types (practicalswift)
3c82b92d2e tests: Add fuzzing harness for functions taking floating-point types as input (practicalswift)
c2bd588860 Add missing includes (practicalswift)
Pull request description:
Add simple fuzzing harness for functions with floating-point parameters (such as `ser_double_to_uint64(double)`, etc.).
Add serialization/deserialization fuzzing for integral types.
Add missing includes.
To test this PR:
```
$ make distclean
$ ./autogen.sh
$ CC=clang CXX=clang++ ./configure --enable-fuzz \
--with-sanitizers=address,fuzzer,undefined
$ make
$ src/test/fuzz/float
…
```
Top commit has no ACKs.
Tree-SHA512: 9b5a0c4838ad18d715c7398e557d2a6d0fcc03aa842f76d7a8ed716170a28f17f249eaede4256998aa3417afe2935e0ffdfaa883727d71ae2d2d18a41ced24b5
fac52dafa0 test: Set catch_system_errors=no on boost unit tests (MarcoFalke)
Pull request description:
Closes#16700
Can be tested by adding an `assert(0)` and then running either `make check` or `./src/test/test_bitcoin -t bla_tests --catch_system_errors=no/yes`
ACKs for top commit:
practicalswift:
ACK fac52dafa0
Empact:
Tested ACK fac52dafa0
Tree-SHA512: ec00636951b2c1137aaf43610739d78d16f823f7da76a726d47f93b8b089766fb66b21504b3c5413bcf8b6b5c3db0ad74027d677db24a44487d6d79a6bdee2e0
Make LegacyScriptPubKeyMan::CanProvide method able to recognize p2sh scripts
when the redeem script is present in the mapScripts map without the p2sh script
also having to be added to the mapScripts map. This restores behavior prior to
https://github.com/bitcoin/bitcoin/pull/17261, which I think broke backwards
compatibility with old wallet files by no longer treating addresses created by
`addmultisigaddress` calls before #17261 as solvable.
The reason why tests didn't fail with the CanProvide implementation in #17261
is because of a workaround added in 4a7e43e846
"Store p2sh scripts in AddAndGetDestinationForScript", which masked the problem
for new `addmultisigaddress` RPC calls without fixing it for multisig addresses
already created in old wallet files.
This change adds a lot of comments and allows reverting commit
4a7e43e846 "Store p2sh scripts in
AddAndGetDestinationForScript", so the AddAndGetDestinationForScript() function,
CanProvide() method, and mapScripts map should all be more comprehensible
cc668d06fb tests: Add fuzzing harness for strprintf(...) (practicalswift)
ccc3c76e2b tests: Add fuzzer strprintf to FUZZERS_MISSING_CORPORA (temporarily) (practicalswift)
6ef04912af tests: Update FuzzedDataProvider.h from upstream (LLVM) (practicalswift)
Pull request description:
Add fuzzing harness for `strprintf(…)`.
Update `FuzzedDataProvider.h`.
Avoid hitting some issues in tinyformat (reported upstreams in https://github.com/c42f/tinyformat/issues/70).
---
Found issues in tinyformat:
**Issue 1.** The following causes a signed integer overflow followed by an allocation of 9 GB of RAM (or an OOM in memory constrained environments):
```
strprintf("%.777777700000000$", 1.0);
```
**Issue 2.** The following causes a stack overflow:
```
strprintf("%987654321000000:", 1);
```
**Issue 3.** The following causes a stack overflow:
```
strprintf("%1$*1$*", -11111111);
```
**Issue 4.** The following causes a `NULL` pointer dereference:
```
strprintf("%.1s", (char *)nullptr);
```
**Issue 5.** The following causes a float cast overflow:
```
strprintf("%c", -1000.0);
```
**Issue 6.** The following causes a float cast overflow followed by an invalid integer negation:
```
strprintf("%*", std::numeric_limits<double>::lowest());
```
Top commit has no ACKs.
Tree-SHA512: 9b765559281470f4983eb5aeca94bab1b15ec9837c0ee01a20f4348e9335e4ee4e4fecbd7a1a5a8ac96aabe0f9eeb597b8fc9a2c8faf1bab386e8225d5cdbc18
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
02b9511d6b tests: add tests for GetCoinsCacheSizeState (James O'Beirne)
b17e91d842 refactoring: introduce CChainState::GetCoinsCacheSizeState (James O'Beirne)
Pull request description:
This is part of the [assumeutxo project](https://github.com/bitcoin/bitcoin/projects/11):
Parent PR: #15606
Issue: #15605
Specification: https://github.com/jamesob/assumeutxo-docs/tree/master/proposal
---
This pulls out the routine for detection of how full the coins cache is from
FlushStateToDisk. We use this logic independently when deciding when to flush
the coins cache during UTXO snapshot activation ([see here](231fb5f17e (diff-24efdb00bfbe56b140fb006b562cc70bR5275))).
ACKs for top commit:
ariard:
Code review ACK 02b9511.
ryanofsky:
Code review ACK 02b9511d6b. Just rebase, new COIN_SIZE comment, and new test message since last review
Tree-SHA512: 8bdd78bf68a4a5d33a776e73fcc2857f050d6d102caa4997ed19ca25468c1358e6e728199d61b423033c02e6bc8f00a1d9da52cf17a2d37d70860fca9237ea7c
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.
