- stop putting inbound addresses in the address book
- drop address book entries that can't be used for outbound connections
- distinguish between temporary inbound and permanent outbound peer
addresses
- also create variants to handle proxy connections
(but don't use them yet)
- avoid tracking connection state for isolated connections
- document security constraints for the address book and peer set
* Allow use listen address in config without port
* update comments
* remove not used alias
* use Network::default_port
* Move tests and use toml instead json
* change error message
* Make match more readable
Co-authored-by: teor <teor@riseup.net>
* Stop ignoring inbound message errors and handshake timeouts
To avoid hangs, Zebra needs to maintain the following invariants in the
handshake and heartbeat code:
- each handshake should run in a separate spawned task
(not yet implemented)
- every message, error, timeout, and shutdown must update the peer address state
- every await that depends on the network must have a timeout
Once the Connection is created, it should handle timeouts.
But we need to handle timeouts during handshake setup.
* Avoid hangs by adding a timeout to the candidate set update
Also increase the fanout from 1 to 2, to increase address diversity.
But only return permanent errors from `CandidateSet::update`, because
the crawler task exits if `update` returns an error.
Also log Peers response errors in the CandidateSet.
* Use the select macro in the crawler to reduce hangs
The `select` function is biased towards its first argument, risking
starvation.
As a side-benefit, this change also makes the code a lot easier to read
and maintain.
* Split CrawlerAction::Demand into separate actions
This refactor makes the code a bit easier to read, at the cost of
sometimes blocking the crawler on `candidates.next()`.
That's ok, because `next` only has a short (< 100 ms) delay. And we're
just about to spawn a separate task for each handshake.
* Spawn a separate task for each handshake
This change avoids deadlocks by letting each handshake make progress
independently.
* Move the dial task into a separate function
This refactor improves readability.
* Fix buggy future::select function usage
And document the correctness of the new code.
Log a "Trying..." message before each listener opens, to see if the
delay is inside Zebra, or in the test harness or OS.
Also report the configured and actual ports where possible, for better
diagnostics.
Design:
- Add a `PeerAddrState` to each `MetaAddr`
- Use a single peer set for all peers, regardless of state
- Implement time-based liveness as an `AddressBook` method, rather than
a `PeerAddrState` variant
- Delete `AddressBook.by_state`
Implementation:
- Simplify `AddressBook` changes using `update` and `take` modifier
methods
- Simplify the `AddressBook` iterator implementation, replacing it with
methods that are more obviously correct
- Consistently collect peer set metrics
Documentation:
- Expand and update the peer set documentation
We can optimise later, but for now we want simple code that is more
obviously correct.
* replace to_socket_addrs
* refactor `resolve()` into `resolve_host()`
* use `resolve_host()` to resolve config peers
* add DNS_LOOKUP_TIMEOUT constant
* don't block the main thread in initialize
* add hint for port error
* add issue filter for port panic
* add lock file hint
* add metrics endpoint port conflict hint
* add hint for tracing endpoint port conflict
* add acceptance test for resource conflics
* Split out common conflict test code into a function
* Add state, metrics, and tracing conflict tests
* Add a full set of stderr acceptance test functions
This change makes the stdout and stderr acceptance test interfaces
identical.
* move Zcash listener opening
* add todo about hint for disk full
* add constant for lock file
* match path in state cache
* don't match windows cache path
* Use Display for state path logs
Avoids weird escaping on Windows when using Debug
* Add Windows conflict error messages
* Turn PORT_IN_USE_ERROR into a regex
And add another alternative Windows-specific port error
Co-authored-by: teor <teor@riseup.net>
Co-authored-by: Jane Lusby <jane@zfnd.org>
## Motivation
This PR is motivated by the regression identified in https://github.com/ZcashFoundation/zebra/issues/1349. That PR notes that the metrics stopped working for most of the crates other than `zebrad`.
## Solution
This PR resolves the regression by deduplicating the `metrics` crate dependency. During a recent change we upgraded the metrics version in `zebrad` and a couple other of our crates, but we never updated the dependencies in `zebra-state`, `zebra-consensus`, or `zebra-network`. This caused the metrics macros to attempt to retrieve the current metrics exporter through the wrong function. We would install the metrics exporter in `0.13`, but then attempt to look it up through the `0.12` crate, which contains a different instance of the metrics exporter static variable which is unset. Doing this causes the metrics macros to return `None` for the current exporter after which they just silently give up.
## Related Issues
closes https://github.com/ZcashFoundation/zebra/issues/1349
## Follow Up Work
I noticed we have quite a few duplicate dependencies in our tree. We might be able to save some compilation time by auditing those and deduplicating them as much as possible.
- https://github.com/ZcashFoundation/zebra/issues/1582
Co-authored-by: teor <teor@riseup.net>
* warn: if there are no peers at all
* info: if there are no ready peers
* trace: the number of ready and unready peers for every request
Log at most one warn or info log per minute, to avoid flooding the
terminal with log lines. Suppress warn and info logs for the first
minute, while the peer set is starting up.
Closes#1183.
The peer set maintains a preselected ready service that it can use to
perform power-of-two-choices (p2c) routing of requests. Ready services
are stored by key (socket address) in an `IndexMap`, and the preselected
service is represented by an `Option<usize>` indexing that map. This
means that whenever the set of ready services changes (e.g., a service
is removed from the peer set, or a service is taken to be used to
process a request), the preselected index is invalidated. The original
P2C-only implementation maintained this invariant but did not document
it.
The change to inventory-based routing introduced a bug by failing to
maintain this invariant and appropriately invalidate the preselected
index. However, this was only noticeable approximately 1/N of the time
on the next request after an inventory-directed request, so the bug
occurred infrequently. Luckily, the use of `.expect` caused the bug to
be an immediate panic, making it possible to identify by inspecting all
uses of the ready service map.
This change is mostly mechanical, with the exception of the changes to the
`tower-batch` middleware. This middleware was adapted from `tower::buffer`,
and the `tower::buffer` code was changed to implement its own bounded queue,
because Tokio 0.3 removed the `mpsc::Sender::poll_send` method. See
ddc64e8d4d
for more context on the Tower changes. To match Tower as closely as possible
in order to be able to upstream `tower-batch`, those changes are copied from
`tower::Buffer` to `tower-batch`.
This addresses at least three pain points:
- we were affected by bugs that were already fixed in git, but not in
the released crate;
- we can use service combinators to transform requests and responses;
- we can use the hedge middleware.
The version in git is still marked as 0.3.1 but these changes will be
part of tower 0.4: https://github.com/tower-rs/tower/issues/431
The GetPeers requests sent while crawling the network are randomly
load-balanced over available peers. But at the very beginning, they may
be both routed to the same peer, causing network initialization to be
delayed while the second one times out (since zcashd only ever responds
to the first addr message).
Only sending one GetPeers request per candidate set update means we
crawl the network a little more slowly, but avoids hanging on start.
This commit makes several related changes to the network code:
- adds a `TransactionsByHash(HashSet<transaction::Hash>)` request and
`Transactions(Vec<Arc<Transaction>>)` response pair that allows
fetching transactions from a remote peer;
- adds a `PushTransaction(Arc<Transaction>)` request that pushes an
unsolicited transaction to a remote peer;
- adds an `AdvertiseTransactions(HashSet<transaction::Hash>)` request
that advertises transactions by hash to a remote peer;
- adds an `AdvertiseBlock(block::Hash)` request that advertises a block
by hash to a remote peer;
Then, it modifies the connection state machine so that outbound
requests to remote peers are handled properly:
- `TransactionsByHash` generates a `getdata` message and collects the
results, like the existing `BlocksByHash` request.
- `PushTransaction` generates a `tx` message, and returns `Nil` immediately.
- `AdvertiseTransactions` and `AdvertiseBlock` generate an `inv`
message, and return `Nil` immediately.
Next, it modifies the connection state machine so that messages
from remote peers generate requests to the inbound service:
- `getdata` messages generate `BlocksByHash` or `TransactionsByHash`
requests, depending on the content of the message;
- `tx` messages generate `PushTransaction` requests;
- `inv` messages generate `AdvertiseBlock` or `AdvertiseTransactions`
requests.
Finally, it refactors the request routing logic for the peer set to
handle advertisement messages, providing three routing methods:
- `route_p2c`, which uses p2c as normal (default);
- `route_inv`, which uses the inventory registry and falls back to p2c
(used for `BlocksByHash` or `TransactionsByHash`);
- `route_all`, which broadcasts a request to all ready peers (used for
`AdvertiseBlock` and `AdvertiseTransactions`).
* network: fix bug in inventory advertisement handling
The RFC https://zebra.zfnd.org/dev/rfcs/0003-inventory-tracking.html described
the use of a `broadcast` channel in place of an `mpsc` channel to get
ring-buffer behavior, keeping a bound on the size of the channel but dropping
old entries when the channel is full.
However, it didn't explicitly describe how this works (the `broadcast` channel
returns a `RecvError::Lagged(u64)` to inform receivers that they lost
messages), so the lag-handling wasn't implemented and I didn't notice in
review.
Instead, the ? operator bubbled the lag error all the way up from
`InventoryRegistry::poll_inventory` through `<PeerSet as Service>::poll_ready`
through various Tower wrappers to users of the peer set. The error propagation
is bad enough, because it caused client errors that shouldn't have happened,
but there's a worse interaction.
The `Service` contract distinguishes between request errors (from
`Service::call`, scoped to the request) and service errors (from
`Service::poll_ready`, scoped to the service). The `Service` contract
specifies that once a service returns an error from `poll_ready`, the service
can be assumed to be failed permanently.
I believe (but haven't tested or carefully worked through the details) that
this caused various tower middleware to report the entire peer set service as
permanently failed due to a transient inventory "error" (more of an indicator),
and I suspect that this is the cause of #1003, where all of the sync
component's requests end up failing because the peer set reported that it
failed permanently. I am able to reproduce #1003 locally before this change
and unable to reproduce it locally after this change, though I have not tested
exhaustively.
* network: add metric for dropped inventory advertisements
Co-authored-by: teor <teor@riseup.net>
Co-authored-by: teor <teor@riseup.net>
The relay flag in the version message is used in conjunction with BIP37 to
receive bloom-filtered transactions. When it is set to false, transactions are
not relayed until a bloom filter is set. Since we don't implement BIP37 (it's
not useful for shielded transactions), this means we'll never receive
transactions.
teor
Kirill Fomichev
Jack Grigg
Jane Lusby
Alfredo Garcia
Henry de Valence
Deirdre Connolly
Jane Lusby