Backport release/v6.6: fix(p2p): make the inbound accept rate configurable and raise its default

[bdchatham]

Backport of #3899 to release/v6.6. Done by hand — see below.

Why this is manual

The UCI backport action refused it:

Backport failed because this pull request contains merge commits.

#3899 was updated by merging main in to resolve conflicts, and the action cherry-picks a PR's commits individually. Configuring merge_commits: skip would have been the wrong fix, since that merge commit is where the conflict resolution lives.

Cherry-picking the squash (d17806f6c) directly also does not work cleanly: it mis-aligns createRouter, splicing main's signature and return shape into this branch's body while marking only part of the damage. So the three affected files were reconstructed from the release/v6.6 side instead of patched out of a bad merge. config.go, toml.go, and the three config test files applied cleanly and are unmodified from the source commit.

The resolution is the inverse of the one on main

#3922 — which unwraps MaxDialRate/MaxAcceptRate from Option[rate.Limit] to plain rate.Limit — is on main only. So this branch keeps the Option form:

	main	here
field	MaxAcceptRate rate.Limit	MaxAcceptRate utils.Option[rate.Limit]
setup.go	MaxAcceptRate: acceptRate	MaxAcceptRate: utils.Some(acceptRate)
routeroptions_test.go	Validate-based rewrite	#3899's original fallback test

pacingRate and p2pRouterOptions are introduced by #3899 itself rather than pre-existing main drift, so both come across. createRouter here keeps its own signature — p2pMetrics first, three return values — and just calls p2pRouterOptions.

One difference that is load-bearing

On main, dropping #3899's raised package-level fallback was safe because #3922 added a Validate() guard rejecting a zero rate, so a construction site that forgets the field fails loudly.

This branch has no such guard. So maxAcceptRate() keeps .Or(rate.Every(10 * time.Millisecond)). Without it, an unset field silently inherits the old 1/s and the backport ships no behaviour change at all.

Verification

• gofmt -s and go vet clean
• ./sei-tendermint/config/... and ./sei-tendermint/internal/p2p/ green
• TestP2PRouterOptions_PacingAndBudgetWiring (7 subtests) and TestRouterOptionsPacingDefaults pass
• ./sei-tendermint/node/ has 3 failures — TestNodeStartStop, TestNodeRestartEventAllowsRecreate, TestNodeSetPrivValTCP — which I confirmed are identical on pristine release/v6.6, not introduced here

Why it matters for v6.6

The seeds run v6.6.0. Their inbound accept limiter is pinned at 1/s with no way to reach it from config, so the kernel completes handshakes into the listen backlog faster than the loop drains it and arriving peers time out — a node that accepts TCP and then says nothing. That is the observed state of all three prod-cell seeds.

Paired with sei-config v0.0.26, which carries the accept-interval key through the config schema.

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Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Aug 17, 2026, 4:28 PM

[codecov]

Codecov Report

❌ Patch coverage is 79.41176% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 58.13%. Comparing base (bb738bc) to head (36705fa).

Files with missing lines	Patch %	Lines
sei-tendermint/node/setup.go	73.07%	3 Missing and 4 partials ⚠️

Additional details and impacted files

@@               Coverage Diff                @@
##           release/v6.6    #3939      +/-   ##
================================================
- Coverage         59.00%   58.13%   -0.88%     
================================================
  Files              2225     2151      -74     
  Lines            183577   175032    -8545     
================================================
- Hits             108320   101749    -6571     
+ Misses            65511    64238    -1273     
+ Partials           9746     9045     -701     

Flag	Coverage Δ
sei-chain-pr	72.01% <79.41%> (?)
sei-db	70.41% <ø> (ø)
sei-db-state-db	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
sei-tendermint/config/config.go	74.94% <100.00%> (+0.35%)	⬆️
sei-tendermint/config/toml.go	55.00% <ø> (ø)
sei-tendermint/internal/p2p/routeroptions.go	81.25% <100.00%> (ø)
sei-tendermint/node/setup.go	70.03% <73.07%> (+0.89%)	⬆️

... and 74 files with indirect coverage changes

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[cursor]

PR Summary

Medium Risk
Touches core P2P connection acceptance pacing and defaults; mis-tuned accept-interval can still starve inbound peers, but changes are narrowly scoped with validation and tests.

Overview
Fixes inbound peer acquisition by making the P2P accept-loop rate operator-tunable and raising the effective default from ~1/s to ~100/s (default accept-interval 10ms).

Adds accept-interval to [p2p] (documented in config.toml; dial-interval stays parse-only, not in the template). Config.ValidateBasic now validates [p2p], including non-negative dial-interval / accept-interval; 0 disables the accept limiter (rate.Inf). Node startup maps both intervals into RouterOptions via new pacingRate / p2pRouterOptions (including MaxAcceptRate), with errors on negative values even when validation was skipped on deploy.

maxAcceptRate() fallback when unset is 10ms (load-bearing on this branch without main’s zero-rate guard). Tests cover template presence, viper compat for older configs, and router wiring.

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