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author | fanquake <fanquake@gmail.com> | 2021-08-04 10:52:48 +0800 |
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committer | fanquake <fanquake@gmail.com> | 2021-08-04 10:53:08 +0800 |
commit | 3308c61091b6b7cb22569f3abadea6d001295c90 (patch) | |
tree | 7b742a311bb8eceecf1f5bce182b85b5ff4ca69e /src | |
parent | eaf09bda4ab21f79f89822d2c6fa3d7a3ce57b0d (diff) | |
parent | 036d7eadf5dd0e06e0734a5d78dbe28f4bfaa07f (diff) |
Merge bitcoin/bitcoin#22576: doc: Update high-level addrman description
036d7eadf5dd0e06e0734a5d78dbe28f4bfaa07f doc: Correct description of CAddrMan::Create() (Amiti Uttarwar)
318176aff1ded36d1fbc5977f288ac3bac1d8712 doc: Update high-level addrman description (Martin Zumsande)
Pull request description:
The high-level description of `addrman` has outdated information with respect to the eviction behavior, both for the New and Tried tables (at least since #5941) - this has confused me in the past.
This PR corrects this and also adds basic info about the bucket size and position.
ACKs for top commit:
amitiuttarwar:
reACK 036d7eadf5dd0e06e0734a5d78dbe28f4bfaa07f
jnewbery:
ACK 036d7eadf5dd0e06e0734a5d78dbe28f4bfaa07f
Tree-SHA512: 3f0635d765f5e580a1fae31187742a833cef66ef2286d40eeb28f2253521260038e16e5f1a65741464a2ddfdbeb5c0f1bc38bf73841e600639033d59c3c534e4
Diffstat (limited to 'src')
-rw-r--r-- | src/addrman.h | 21 |
1 files changed, 12 insertions, 9 deletions
diff --git a/src/addrman.h b/src/addrman.h index 4d8d05a99a..736d9783e6 100644 --- a/src/addrman.h +++ b/src/addrman.h @@ -104,19 +104,23 @@ public: * * Make sure no (localized) attacker can fill the entire table with his nodes/addresses. * * To that end: - * * Addresses are organized into buckets. - * * Addresses that have not yet been tried go into 1024 "new" buckets. - * * Based on the address range (/16 for IPv4) of the source of information, 64 buckets are selected at random. + * * Addresses are organized into buckets that can each store up to 64 entries. + * * Addresses to which our node has not successfully connected go into 1024 "new" buckets. + * * Based on the address range (/16 for IPv4) of the source of information, or if an asmap is provided, + * the AS it belongs to (for IPv4/IPv6), 64 buckets are selected at random. * * The actual bucket is chosen from one of these, based on the range in which the address itself is located. + * * The position in the bucket is chosen based on the full address. * * One single address can occur in up to 8 different buckets to increase selection chances for addresses that * are seen frequently. The chance for increasing this multiplicity decreases exponentially. - * * When adding a new address to a full bucket, a randomly chosen entry (with a bias favoring less recently seen - * ones) is removed from it first. + * * When adding a new address to an occupied position of a bucket, it will not replace the existing entry + * unless that address is also stored in another bucket or it doesn't meet one of several quality criteria + * (see IsTerrible for exact criteria). * * Addresses of nodes that are known to be accessible go into 256 "tried" buckets. * * Each address range selects at random 8 of these buckets. * * The actual bucket is chosen from one of these, based on the full address. - * * When adding a new good address to a full bucket, a randomly chosen entry (with a bias favoring less recently - * tried ones) is evicted from it, back to the "new" buckets. + * * When adding a new good address to an occupied position of a bucket, a FEELER connection to the + * old address is attempted. The old entry is only replaced and moved back to the "new" buckets if this + * attempt was unsuccessful. * * Bucket selection is based on cryptographic hashing, using a randomly-generated 256-bit key, which should not * be observable by adversaries. * * Several indexes are kept for high performance. Defining DEBUG_ADDRMAN will introduce frequent (and expensive) @@ -696,8 +700,7 @@ private: //! Find an entry. CAddrInfo* Find(const CNetAddr& addr, int *pnId = nullptr) EXCLUSIVE_LOCKS_REQUIRED(cs); - //! find an entry, creating it if necessary. - //! nTime and nServices of the found node are updated, if necessary. + //! Create a new entry and add it to the internal data structures mapInfo, mapAddr and vRandom. CAddrInfo* Create(const CAddress &addr, const CNetAddr &addrSource, int *pnId = nullptr) EXCLUSIVE_LOCKS_REQUIRED(cs); //! Swap two elements in vRandom. |