feat(protocol): add bridge rate limiter for ETH and ERC20s

[dantaik]

Following open zeppelin's suggestion, this PR introduces a feature to manage cross-chain quota. For each token, we can config the daily quota.

Note that the quota is only consumed and checked on the destination chain (process message and retry message) and on the source chain (recall message but NOT send message). So if I set 1000 ether daily quota on L1, on L2, people can still withdraw more than 1000 ether, but on L1, they can NOT withdraw more than 1000 ether per day, so bridge and UI doesn't need to add new features to check available quota when messages are sent.

The relayer backend does need to check the quota before processing messages, otherwise, the relayer will not get paid.

Lets vote on this. I'm ok with or without this PR to be merged.

• thumb up for yes
• thumb down for no

[openzeppelin-code[bot]]

feat(protocol): add bridge rate limiter for ETH and ERC20s

Generated at commit: 36d6573b0aa2a3f343c3b1000c7e6f1b978ecf5b

🚨 Report Summary

	Severity Level	Results
Contracts	Critical High Medium Low Note Total	2 2 0 5 41 50
Dependencies	Critical High Medium Low Note Total	0 0 0 0 0 0

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[dantaik]

Need to add some tests later

[cyberhorsey]

@dantaik given the relayer sends multiple messages at a time (ie: it has multiple pending transactions simultaneously), what would be the best way to ensure we don't waste gas on reverted transactions, given this new rate limit cap?

Is there also a method or parameter we can add to get when the issuance is reset, so the relayer knows how long to wait? It could be calculated now using off chain code duplication now, but maybe easier to just add a member onchain to call.

[Brechtpd]

@dantaik given the relayer sends multiple messages at a time (ie: it has multiple pending transactions simultaneously), what would be the best way to ensure we don't waste gas on reverted transactions, given this new rate limit cap?

Not specifically for this but in general the relayer will have the same problem as people proposing blocks in a based rollup: So I will again shill hooking into PBS also for this like with https://docs.flashbots.net/flashbots-protect/overview (though I don't know what the best service is to do this in practice). There is no other way (except maybe some of the account abstraction stuff for revert protection but I don't think that's directly usable now and maybe also not sufficient) to prevent both other parties stealing transactions and also ensuring no money is wasted on failed/reverted transactions.

Based rollups can't exist without hooking into PBS for the same reason. The problem here where messages can be processed by anyone is the same, though here keeping the transaction private is less of a concern but you still need to have protection against failed transactions so have to make the L1 tx fee payment conditional on the successful execution somehow. Otherwise as soon as there are multiple relayers processing messages there will be (as vitalik called it) total anarchy and everybody losing money on failed transactions.

[cyberhorsey]

@dantaik given the relayer sends multiple messages at a time (ie: it has multiple pending transactions simultaneously), what would be the best way to ensure we don't waste gas on reverted transactions, given this new rate limit cap?

Not specifically for this but in general the relayer will have the same problem as people proposing blocks in a based rollup: So I will again shill hooking into PBS also for this like with https://docs.flashbots.net/flashbots-protect/overview (though I don't know what the best service is to do this in practice). There is no other way (except maybe some of the account abstraction stuff for revert protection but I don't think that's directly usable now and maybe also not sufficient) to prevent both other parties stealing transactions and also ensuring no money is wasted on failed/reverted transactions.

Based rollups can't exist without hooking into PBS for the same reason. The problem here where messages can be processed by anyone is the same, though here keeping the transaction private is less of a concern but you still need to have protection against failed transactions so have to make the L1 tx fee payment conditional on the successful execution somehow. Otherwise as soon as there are multiple relayers processing messages there will be (as vitalik called it) total anarchy and everybody losing money on failed transactions.

:|

[dantaik]

• There is a QuotaUpdated event, it will be emitted when the quota changed by the admin.
• availableQuota can be used to query the currently available quota, one additional parameter is added so you can query the available quota at current timestamp + x seconds

[dantaik]

BTW, we'll deploy a QuotaManager on only L1 for Ether and USDC/USDT initially.

[cyberhorsey]

BTW, we'll deploy a QuotaManager on only L1 for Ether and USDC/USDT initially.

so Quota manager should be optional in the relayer. Got it, will update my PR accordingly.