net: introduce block tracker to retry to download blocks after failure #35113

pull optout21 wants to merge 6 commits into bitcoin:master from optout21:block-dl changing 8 files +330 −10

optout21 commented at 9:01 AM on April 19, 2026: contributor

Revival of closed/stale #27837, authored by @furszy . The change is taken (as of b18c72cfcd6f27070928bc0ba16db6897960f211) and rebased to current master. Original description follows.

Coming from #27652, part of #29183.

The general idea is to keep track of the user requested blocks so, in case of a bad behaving peer or a network disconnection, they can be fetched from another one automatically without any further user interaction.

This was requested by users because the getblockfrompeer RPC command lacks the functionality to notify them about block request failures or peer disconnections (which is expected due to the asynchronous nature of the block requests).

Currently, this new functionality is limited to blocks requested by the user via the 'getblockfrompeer' RPC command.

In the future, this class could expand its scope and be utilized in the regular chain synchronization process. Or, even could be employed in special procedures like a prune node rescan that uses BIP158 block filters, or even into BIP157 itself.

net: FetchBlock, disallow requesting blocks from network limited peers

This is in preparation for block tracker.

Co-authored-by: furszy <matiasfurszyfer@protonmail.com>

5d3852f01c

net: FetchBlock, disallow requesting block to the same peer multiple times
Co-authored-by: furszy <matiasfurszyfer@protonmail.com>
20b842729f

net: introduce BlockRequestTracker

Co-authored-by: furszy <matiasfurszyfer@protonmail.com>

691cb0426a

rpc: getblockfrompeer, connect block tracking mechanism and add coverage

If the initial block fetching process fails, the p2p layer will be in
charge of fetching the block from 'any' connected peer.
Re-trying to download the block from different peers until it is
received.

Co-authored-by: furszy <matiasfurszyfer@protonmail.com>

2cedb97b93

rpc: getblockfrompeer, introduce fetch from "any" peer functionality

If no 'peer_id' is provided, 'getblockfrompeer' will delegate
the peer selection to the internal block downloading logic.

Co-authored-by: furszy <matiasfurszyfer@protonmail.com>

e7d0aac60a

rpc: getblockfrompeer, add one-shot block requests capability

Allowing what we had before, a single block request with no automatic
retry nor tracking mechanism.

Co-authored-by: furszy <matiasfurszyfer@protonmail.com>

d3951af263

DrahtBot added the label P2P on Apr 19, 2026
DrahtBot commented at 9:01 AM on April 19, 2026: contributor



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#27652 Allow getblockfrompeer to use any peer #27837 net: introduce block tracker to retry to download blocks after failure #29183 Prune Node Rescan Project Tracking

net: introduce block tracker to retry to download blocks after failure #35113

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