diff options
author | Martin Zumsande <mzumsande@gmail.com> | 2021-07-28 23:48:34 +0200 |
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committer | Martin Zumsande <mzumsande@gmail.com> | 2021-08-02 21:24:12 +0200 |
commit | 318176aff1ded36d1fbc5977f288ac3bac1d8712 (patch) | |
tree | 01a2acbf57d404a868a01afcb9ba62ae8fbed106 /src/addrman.h | |
parent | 4b1fb50def0dea0cd320bc43c12d9a12edde0390 (diff) |
doc: Update high-level addrman description
Diffstat (limited to 'src/addrman.h')
-rw-r--r-- | src/addrman.h | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/src/addrman.h b/src/addrman.h index 1fc64ac07f..7e87457a9f 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) |