enode.Node was recently changed to store a cache of endpoint information. The IP address in the cache is a netip.Addr. I chose that type over net.IP because it is just better. netip.Addr is meant to be used as a value type. Copying it does not allocate, it can be compared with ==, and can be used as a map key.
This PR changes most uses of Node.IP() into Node.IPAddr(), which returns the cached value directly without allocating.
While there are still some public APIs left where net.IP is used, I have converted all code used internally by p2p/discover to the new types. So this does change some public Go API, but hopefully not APIs any external code actually uses.
There weren't supposed to be any semantic differences resulting from this refactoring, however it does introduce one: In package p2p/netutil we treated the 0.0.0.0/8 network (addresses 0.x.y.z) as LAN, but netip.Addr.IsPrivate() doesn't. The treatment of this particular IP address range is controversial, with some software supporting it and others not. IANA lists it as special-purpose and invalid as a destination for a long time, so I don't know why I put it into the LAN list. It has now been marked as special in p2p/netutil as well.
Here we clean up internal uses of type discover.node, converting most code to use
enode.Node instead. The discover.node type used to be the canonical representation of
network hosts before ENR was introduced. Most code worked with *node to avoid conversions
when interacting with Table methods. Since *node also contains internal state of Table and
is a mutable type, using *node outside of Table code is prone to data races. It's also
cleaner not having to wrap/unwrap *enode.Node all the time.
discover.node has been renamed to tableNode to clarify its purpose.
While here, we also change most uses of net.UDPAddr into netip.AddrPort. While this is
technically a separate refactoring from the *node -> *enode.Node change, it is more
convenient because *enode.Node handles IP addresses as netip.Addr. The switch to package
netip in discovery would've happened very soon anyway.
The change to netip.AddrPort stops at certain interface points. For example, since package
p2p/netutil has not been converted to use netip.Addr yet, we still have to convert to
net.IP/net.UDPAddr in a few places.
It seems the semantic differences between addFoundNode and addInboundNode were lost in
#29572. My understanding is addFoundNode is for a node you have not contacted directly
(and are unsure if is available) whereas addInboundNode is for adding nodes that have
contacted the local node and we can verify they are active.
handleAddNode seems to be the consolidation of those two methods, yet it bumps the node in
the bucket (updating it's IP addr) even if the node was not an inbound. This PR fixes
this. It wasn't originally caught in tests like TestTable_addSeenNode because the
manipulation of the node object actually modified the node value used by the test.
New logic is added to reject non-inbound updates unless the sequence number of the
(signed) ENR increases. Inbound updates, which are published by the updated node itself,
are always accepted. If an inbound update changes the endpoint, the node will be
revalidated on an expedited schedule.
Co-authored-by: Felix Lange <fjl@twurst.com>
Node discovery periodically revalidates the nodes in its table by sending PING, checking
if they are still alive. I recently noticed some issues with the implementation of this
process, which can cause strange results such as nodes dropping unexpectedly, certain
nodes not getting revalidated often enough, and bad results being returned to incoming
FINDNODE queries.
In this change, the revalidation process is improved with the following logic:
- We maintain two 'revalidation lists' containing the table nodes, named 'fast' and 'slow'.
- The process chooses random nodes from each list on a randomized interval, the interval being
faster for the 'fast' list, and performs revalidation for the chosen node.
- Whenever a node is newly inserted into the table, it goes into the 'fast' list.
Once validation passes, it transfers to the 'slow' list. If a request fails, or the
node changes endpoint, it transfers back into 'fast'.
- livenessChecks is incremented by one for successful checks. Unlike the old implementation,
we will not drop the node on the first failing check. We instead quickly decay the
livenessChecks give it another chance.
- Order of nodes in bucket doesn't matter anymore.
I am also adding a debug API endpoint to dump the node table content.
Co-authored-by: Martin HS <martin@swende.se>
* p2p/discover: add liveness check in collectTableNodes
* p2p/discover: fix test
* p2p/discover: rename to appendLiveNodes
* p2p/discover: add dedup logic back
* p2p/discover: simplify
* p2p/discover: fix issue found by test
This change
- Removes interface `log.Format`,
- Removes method `log.FormatFunc`,
- unexports `TerminalHandler.TerminalFormat` formatting methods (renamed to `TerminalHandler.format`)
- removes the notion of `log.Lazy` values
The lazy handler was useful in the old log package, since it
could defer the evaluation of costly attributes until later in the
log pipeline: thus, if the logging was done at 'Trace', we could
skip evaluation if logging only was set to 'Info'.
With the move to slog, this way of deferring evaluation is no longer
needed, since slog introduced 'Enabled': the caller can thus do
the evaluate-or-not decision at the callsite, which is much more
straight-forward than dealing with lazy reflect-based evaluation.
Also, lazy evaluation would not work with 'native' slog, as in, these
two statements would be evaluated differently:
```golang
log.Info("foo", "my lazy", lazyObj)
slog.Info("foo", "my lazy", lazyObj)
```
* p2p/discover: remove ReadRandomNodes
Even though it's public, this method is not callable by code outside of
package p2p/discover because one can't get a valid instance of Table.
* p2p/discover: add Table.Nodes
* p2p/discover: make Table settings configurable
In unit tests and externally developed cmd/devp2p test runs, it can be
useful to tune the timer intervals used by Table.
This improves readability of function 'push'.
sort.Search(N, ...) will at most return N when no match, so ix should be compared
with N. The previous version would compare ix with N+1 in case an additional item
was appended. No bug resulted from this comparison, but it's not easy to understand
why.
Co-authored-by: Felix Lange <fjl@twurst.com>
This change improves discovery behavior in small networks. Very small
networks would often fail to bootstrap because all member nodes were
dropping table content due to findnode failure. The check is now changed
to avoid dropping nodes on findnode failure when their bucket is almost
empty. It also relaxes the liveness check requirement for FINDNODE/v4
response nodes, returning unverified nodes as results when there aren't
any verified nodes yet.
The "findnode failed" log now reports whether the node was dropped
instead of the number of results. The value of the "results" was
always zero by definition.
Co-authored-by: Felix Lange <fjl@twurst.com>
This adds an implementation of the current discovery v5 spec.
There is full integration with cmd/devp2p and enode.Iterator in this
version. In theory we could enable the new protocol as a replacement of
discovery v4 at any time. In practice, there will likely be a few more
changes to the spec and implementation before this can happen.
* p2p/discover: export Ping and RequestENR
These two are useful for checking the status of a node.
* cmd/devp2p: add devp2p debug tool
This is a new tool for debugging p2p issues. It supports a few
basic tasks for now, but many more things can and will be added
in the near future.
devp2p enrdump -- prints ENRs readably
devp2p discv4 ping -- checks if a node is up
devp2p discv4 requestenr -- gets a node's record
devp2p discv4 resolve -- finds a node through the DHT
This change implements EIP-868. The UDPv4 transport announces support
for the extension in ping/pong and handles enrRequest messages.
There are two uses of the extension: If a remote node announces support
for EIP-868 in their pong, node revalidation pulls the node's record.
The Resolve method requests the record unconditionally.
This change restructures the internals of p2p/discover to make room for
the discv5 code which will soon be added to this package.
- packet type names now have a "V4" suffix.
- ListenUDP returns *UDPv4 instead of *Table. This technically breaks
the API but the only caller in go-ethereum is package p2p, which uses
a compatible interface and doesn't need changes.
- The internal transport interface is changed to make Table reusable for v5.
- The 'lookup' code moves from table to transport. This required
updating the lookup unit test to use udpTest instead of a custom transport.
This resolves a minor issue where neighbors responses containing less
than 16 nodes would bump the failure counter, removing the node. One
situation where this can happen is a private deployment where the total
number of extant nodes is less than 16.
Issue found by @jsying.
This change clears up confusion around the two ways in which nodes
can be added to the table.
When a neighbors packet is received as a reply to findnode, the nodes
contained in the reply are added as 'seen' entries if sufficient space
is available.
When a ping is received and the endpoint verification has taken place,
the remote node is added as a 'verified' entry or moved to the front of
the bucket if present. This also updates the node's IP address and port
if they have changed.
This change resolves multiple issues around handling of endpoint proofs.
The proof is now done separately for each IP and completing the proof
requires a matching ping hash.
Also remove waitping because it's equivalent to sleep. waitping was
slightly more efficient, but that may cause issues with findnode if
packets are reordered and the remote end sees findnode before pong.
Logging of received packets was hitherto done after handling the packet,
which meant that sent replies were logged before the packet that
generated them. This change splits up packet handling into 'preverify'
and 'handle'. The error from 'preverify' is logged, but 'handle' happens
after the message is logged. This fixes the order. Packet logs now
contain the node ID.
This PR adds enode.LocalNode and integrates it into the p2p
subsystem. This new object is the keeper of the local node
record. For now, a new version of the record is produced every
time the client restarts. We'll make it smarter to avoid that in
the future.
There are a couple of other changes in this commit: discovery now
waits for all of its goroutines at shutdown and the p2p server
now closes the node database after discovery has shut down. This
fixes a leveldb crash in tests. p2p server startup is faster
because it doesn't need to wait for the external IP query
anymore.
Package p2p/enode provides a generalized representation of p2p nodes
which can contain arbitrary information in key/value pairs. It is also
the new home for the node database. The "v4" identity scheme is also
moved here from p2p/enr to remove the dependency on Ethereum crypto from
that package.
Record signature handling is changed significantly. The identity scheme
registry is removed and acceptable schemes must be passed to any method
that needs identity. This means records must now be validated explicitly
after decoding.
The enode API is designed to make signature handling easy and safe: most
APIs around the codebase work with enode.Node, which is a wrapper around
a valid record. Going from enr.Record to enode.Node requires a valid
signature.
* p2p/discover: port to p2p/enode
This ports the discovery code to the new node representation in
p2p/enode. The wire protocol is unchanged, this can be considered a
refactoring change. The Kademlia table can now deal with nodes using an
arbitrary identity scheme. This requires a few incompatible API changes:
- Table.Lookup is not available anymore. It used to take a public key
as argument because v4 protocol requires one. Its replacement is
LookupRandom.
- Table.Resolve takes *enode.Node instead of NodeID. This is also for
v4 protocol compatibility because nodes cannot be looked up by ID
alone.
- Types Node and NodeID are gone. Further commits in the series will be
fixes all over the the codebase to deal with those removals.
* p2p: port to p2p/enode and discovery changes
This adapts package p2p to the changes in p2p/discover. All uses of
discover.Node and discover.NodeID are replaced by their equivalents from
p2p/enode.
New API is added to retrieve the enode.Node instance of a peer. The
behavior of Server.Self with discovery disabled is improved. It now
tries much harder to report a working IP address, falling back to
127.0.0.1 if no suitable address can be determined through other means.
These changes were needed for tests of other packages later in the
series.
* p2p/simulations, p2p/testing: port to p2p/enode
No surprises here, mostly replacements of discover.Node, discover.NodeID
with their new equivalents. The 'interesting' API changes are:
- testing.ProtocolSession tracks complete nodes, not just their IDs.
- adapters.NodeConfig has a new method to create a complete node.
These changes were needed to make swarm tests work.
Note that the NodeID change makes the code incompatible with old
simulation snapshots.
* whisper/whisperv5, whisper/whisperv6: port to p2p/enode
This port was easy because whisper uses []byte for node IDs and
URL strings in the API.
* eth: port to p2p/enode
Again, easy to port because eth uses strings for node IDs and doesn't
care about node information in any way.
* les: port to p2p/enode
Apart from replacing discover.NodeID with enode.ID, most changes are in
the server pool code. It now deals with complete nodes instead
of (Pubkey, IP, Port) triples. The database format is unchanged for now,
but we should probably change it to use the node database later.
* node: port to p2p/enode
This change simply replaces discover.Node and discover.NodeID with their
new equivalents.
* swarm/network: port to p2p/enode
Swarm has its own node address representation, BzzAddr, containing both
an overlay address (the hash of a secp256k1 public key) and an underlay
address (enode:// URL).
There are no changes to the BzzAddr format in this commit, but certain
operations such as creating a BzzAddr from a node ID are now impossible
because node IDs aren't public keys anymore.
Most swarm-related changes in the series remove uses of
NewAddrFromNodeID, replacing it with NewAddr which takes a complete node
as argument. ToOverlayAddr is removed because we can just use the node
ID directly.
* p2p/discover: move bond logic from table to transport
This commit moves node endpoint verification (bonding) from the table to
the UDP transport implementation. Previously, adding a node to the table
entailed pinging the node if needed. With this change, the ping-back
logic is embedded in the packet handler at a lower level.
It is easy to verify that the basic protocol is unchanged: we still
require a valid pong reply from the node before findnode is accepted.
The node database tracked the time of last ping sent to the node and
time of last valid pong received from the node. Node endpoints are
considered verified when a valid pong is received and the time of last
pong was called 'bond time'. The time of last ping sent was unused. In
this commit, the last ping database entry is repurposed to mean last
ping _received_. This entry is now used to track whether the node needs
to be pinged back.
The other big change is how nodes are added to the table. We used to add
nodes in Table.bond, which ran when a remote node pinged us or when we
encountered the node in a neighbors reply. The transport now adds to the
table directly after the endpoint is verified through ping. To ensure
that the Table can't be filled just by pinging the node repeatedly, we
retain the isInitDone check. During init, only nodes from neighbors
replies are added.
* p2p/discover: reduce findnode failure counter on success
* p2p/discover: remove unused parameter of loadSeedNodes
* p2p/discover: improve ping-back check and comments
* p2p/discover: add neighbors reply nodes always, not just during init
This commit adds all changes needed for the merge of swarm-network-rewrite.
The changes:
- build: increase linter timeout
- contracts/ens: export ensNode
- log: add Output method and enable fractional seconds in format
- metrics: relax test timeout
- p2p: reduced some log levels, updates to simulation packages
- rpc: increased maxClientSubscriptionBuffer to 20000
I forgot to change the check in udp.go when I changed Table.bond to be
based on lastPong instead of node presence in db. Rename lastPong to
bondTime and add hasBond so it's clearer what this DB key is used for
now.
* p2p: add DialRatio for configuration of inbound vs. dialed connections
* p2p: add connection flags to PeerInfo
* p2p/netutil: add SameNet, DistinctNetSet
* p2p/discover: improve revalidation and seeding
This changes node revalidation to be periodic instead of on-demand. This
should prevent issues where dead nodes get stuck in closer buckets
because no other node will ever come along to replace them.
Every 5 seconds (on average), the last node in a random bucket is
checked and moved to the front of the bucket if it is still responding.
If revalidation fails, the last node is replaced by an entry of the
'replacement list' containing recently-seen nodes.
Most close buckets are removed because it's very unlikely we'll ever
encounter a node that would fall into any of those buckets.
Table seeding is also improved: we now require a few minutes of table
membership before considering a node as a potential seed node. This
should make it less likely to store short-lived nodes as potential
seeds.
* p2p/discover: fix nits in UDP transport
We would skip sending neighbors replies if there were fewer than
maxNeighbors results and CheckRelayIP returned an error for the last
one. While here, also resolve a TODO about pong reply tokens.
nodeDB.querySeeds was not safe for concurrent use but could be called
concurrenty on multiple goroutines in the following case:
- the table was empty
- a timed refresh started
- a lookup was started and initiated refresh
These conditions are unlikely to coincide during normal use, but are
much more likely to occur all at once when the user's machine just woke
from sleep. The root cause of the issue is that querySeeds reused the
same leveldb iterator until it was exhausted.
This commit moves the refresh scheduling logic into its own goroutine
(so only one refresh is ever active) and changes querySeeds to not use
a persistent iterator. The seed node selection is now more random and
ignores nodes that have not been contacted in the last 5 days.
PR #1621 changed Table locking so the mutex is not held while a
contested node is being pinged. If multiple nodes ping the local node
during this time window, multiple ping packets will be sent to the
contested node. The changes in this commit prevent multiple packets by
tracking whether the node is being replaced.
Table.mutex was being held while waiting for a reply packet, which
effectively made many parts of the whole stack block on that packet,
including the net_peerCount RPC call.
