[feature]: Don't Check Outgoing Policy for Direct Channels.

[ziggie1984]

Policies are used when forwarding payments but should NOT be checked against for direct local channels in pathfinding.

Use Case Example:

I restrict the Min_HTLC for forwarding but I want to send my direct channel peers keysends when rewarding them for inbound liquidity. (see https://twitter.com/alexbosworth/status/1772277264270446647)

Relevant code part:

we check this function also in the LocalEdge case:

lnd/routing/unified_edges.go

Lines 127 to 155 in b76f733

	func (u *unifiedEdge) amtInRange(amt lnwire.MilliSatoshi) bool {
	// If the capacity is available (non-light clients), skip channels that
	// are too small.
	if u.capacity > 0 &&
	amt > lnwire.NewMSatFromSatoshis(u.capacity) {
	log.Tracef("Not enough capacity: amt=%v, capacity=%v",
	amt, u.capacity)
	return false
	}
	// Skip channels for which this htlc is too large.
	if u.policy.MessageFlags.HasMaxHtlc() &&
	amt > u.policy.MaxHTLC {
	log.Tracef("Exceeds policy's MaxHTLC: amt=%v, MaxHTLC=%v",
	amt, u.policy.MaxHTLC)
	return false
	}
	// Skip channels for which this htlc is too small.
	if amt < u.policy.MinHTLC {
	log.Tracef("below policy's MinHTLC: amt=%v, MinHTLC=%v",
	amt, u.policy.MinHTLC)
	return false
	}
	return true
	}

[bitromortac]

This may not be only solved by ignoring that check, I think one would also need to distinguish the case in the link where for an update_add_htlc the min htlc size is checked?

lnd/lnwallet/channel.go

Line 4077 in b76f733

if entry.Amount < constraints.MinHTLC {

edit: nevermind, those are channel funding constraints