…rMan

8765179 fuzz: check that ser+unser produces the same AddrMan (Vasil Dimov)
6408b24 fuzz: move init code to the CAddrManDeterministic constructor (Vasil Dimov)

Pull request description:

  Add a fuzz test that fills addrman with a pile of randomly generated addresses, serializes it to a stream, unserializes the stream to another addrman object and compares the two.

  Some discussion of this already happened at jnewbery#18.

ACKs for top commit:
  practicalswift:
    cr ACK 8765179
  jonatack:
    ACK 8765179 rebased to current master, reviewed, fuzz build, ran `FUZZ=addrman_serdeser src/test/fuzz/fuzz`

Tree-SHA512: 7eda79279f14f2649840bf752e575d7b02cbaad541f74f7254855ebd4a32da988f042d78aa9228983350283bb74dd0c71f51f04c0846889c3ba2f19f01a0c303

The new test was added in bitcoin/bitcoin#21129.

57ce203 fuzz: allow lower number of sources (Martin Zumsande)
acf656d fuzz: Use public interface to fill addrman tried tables (Martin Zumsande)
eb2e113 addrman: Improve performance of Good (Martin Zumsande)

Pull request description:

  Currently, `CAddrman::Good()` is rather slow because the process of moving an addr from new to tried involves looping over the new tables twice:
  1) In `Good_()`, there is a loop searching for a new bucket the addr is currently in, but this information is never used except for aborting if it is not found anywhere (since [this commit](e6b343d#diff-49d1faa58beca1ee1509a247e0331bb91f8604e30a483a7b2dea813e6cea02e2R263) it is no longer passed to `MakeTried`)
  This is unnecessary because in a non-corrupted addrman, an address that is not in New must be either in Tried or not at all in addrman, both cases in which we'd return early in `Good_()` and never get to this point.
  I removed this loop (and left a check for `nRefCount` as a belt-and-suspenders check).

  2) In `MakeTried()`, which is called from `Good_()`, another loop removes all instances of this address from new. This can be spedup by stopping the search at  `nRefCount==0`. Further reductions in `nRefCount` would only lead to an assert anyway.
  Moreover, the search can be started at the bucket determined by the source of the addr for which `Good` was called, so that if it is present just once in New, no further buckets need to be checked.

  While calls to `Good()` are not that frequent normally, the performance gain is clearly seen in the fuzz target `addman_serdeser`, where, because of the slowness in creating a decently filled addrman, a shortcut was created that would directly populate the tried tables by reaching into addrman's internals, bypassing `Good()` (#21129).
  I removed this workaround in the second commit: Using `Good()` is still slower by a factor of 2 (down from a factor of ~60 before), but I think that this compensated by the advantages of not having to reach into the internal structures of addrman  (see jnewbery#18 (comment)).

  [Edit]: For benchmark results see #22974 (comment) and #22974 (comment) - the benchmark `AddrManGood` shows a significant speedup by a factor >100.

ACKs for top commit:
  naumenkogs:
    ACK 57ce203
  jnewbery:
    ACK 57ce203
  laanwj:
    Code review ACK 57ce203
  theStack:
    ACK 57ce203
  vasild:
    ACK 57ce203

Tree-SHA512: fb6dfc198f2e28bdbb41cef9709828f22d83b4be0e640a3155ca42e771b6f58466de1468f54d773e794f780a79113f9f7d522032e87fdd75bdc4d99330445198

57ce203 fuzz: allow lower number of sources (Martin Zumsande)
acf656d fuzz: Use public interface to fill addrman tried tables (Martin Zumsande)
eb2e113 addrman: Improve performance of Good (Martin Zumsande)

Pull request description:

  Currently, `CAddrman::Good()` is rather slow because the process of moving an addr from new to tried involves looping over the new tables twice:
  1) In `Good_()`, there is a loop searching for a new bucket the addr is currently in, but this information is never used except for aborting if it is not found anywhere (since [this commit](bitcoin@e6b343d#diff-49d1faa58beca1ee1509a247e0331bb91f8604e30a483a7b2dea813e6cea02e2R263) it is no longer passed to `MakeTried`)
  This is unnecessary because in a non-corrupted addrman, an address that is not in New must be either in Tried or not at all in addrman, both cases in which we'd return early in `Good_()` and never get to this point.
  I removed this loop (and left a check for `nRefCount` as a belt-and-suspenders check).

  2) In `MakeTried()`, which is called from `Good_()`, another loop removes all instances of this address from new. This can be spedup by stopping the search at  `nRefCount==0`. Further reductions in `nRefCount` would only lead to an assert anyway.
  Moreover, the search can be started at the bucket determined by the source of the addr for which `Good` was called, so that if it is present just once in New, no further buckets need to be checked.

  While calls to `Good()` are not that frequent normally, the performance gain is clearly seen in the fuzz target `addman_serdeser`, where, because of the slowness in creating a decently filled addrman, a shortcut was created that would directly populate the tried tables by reaching into addrman's internals, bypassing `Good()` (bitcoin#21129).
  I removed this workaround in the second commit: Using `Good()` is still slower by a factor of 2 (down from a factor of ~60 before), but I think that this compensated by the advantages of not having to reach into the internal structures of addrman  (see jnewbery#18 (comment)).

  [Edit]: For benchmark results see bitcoin#22974 (comment) and bitcoin#22974 (comment) - the benchmark `AddrManGood` shows a significant speedup by a factor >100.

ACKs for top commit:
  naumenkogs:
    ACK 57ce203
  jnewbery:
    ACK 57ce203
  laanwj:
    Code review ACK 57ce203
  theStack:
    ACK 57ce203
  vasild:
    ACK 57ce203

Tree-SHA512: fb6dfc198f2e28bdbb41cef9709828f22d83b4be0e640a3155ca42e771b6f58466de1468f54d773e794f780a79113f9f7d522032e87fdd75bdc4d99330445198