This commit introduces a network simulation framework which
can be used to run simulated networks of devp2p nodes. The
intention is to use this for testing protocols, performing
benchmarks and visualising emergent network behaviour.
Using a Timer over Ticker seems to be a lot better, though I cannot fully
account for why that it behaves so (since Ticker should be more bursty, but not
necessarily more active over time, but that may depend on how long window it
uses to decide on when to tick next)
* p2p/discover, p2p/discv5: add marshaling methods to Node
* p2p/netutil: make Netlist decodable from TOML
* common/math: encode nil HexOrDecimal256 as 0x0
* cmd/geth: add --config file flag
* cmd/geth: add missing license header
* eth: prettify Config again, fix tests
* eth: use gasprice.Config instead of duplicating its fields
* eth/gasprice: hide nil default from dumpconfig output
* cmd/geth: hide genesis block in dumpconfig output
* node: make tests compile
* console: fix tests
* cmd/geth: make TOML keys look exactly like Go struct fields
* p2p: use discovery by default
This makes the zero Config slightly more useful. It also fixes package
node tests because Node detects reuse of the datadir through the
NodeDatabase.
* cmd/geth: make ethstats URL settable through config file
* cmd/faucet: fix configuration
* cmd/geth: dedup attach tests
* eth: add comment for DefaultConfig
* eth: pass downloader.SyncMode in Config
This removes the FastSync, LightSync flags in favour of a more
general SyncMode flag.
* cmd/utils: remove jitvm flags
* cmd/utils: make mutually exclusive flag error prettier
It now reads:
Fatal: flags --dev, --testnet can't be used at the same time
* p2p: fix typo
* node: add DefaultConfig, use it for geth
* mobile: add missing NoDiscovery option
* cmd/utils: drop MakeNode
This exposed a couple of places that needed to be updated to use
node.DefaultConfig.
* node: fix typo
* eth: make fast sync the default mode
* cmd/utils: remove IPCApiFlag (unused)
* node: remove default IPC path
Set it in the frontends instead.
* cmd/geth: add --syncmode
* cmd/utils: make --ipcdisable and --ipcpath mutually exclusive
* cmd/utils: don't enable WS, HTTP when setting addr
* cmd/utils: fix --identity
The p2p packages can now be configured to restrict all communication to
a certain subset of IP networks. This feature is meant to be used for
private networks.
The discovery DHT contains a number of hosts with LAN and loopback IPs.
These get relayed because some implementations do not perform any checks
on the IP.
go-ethereum already prevented relay in most cases because it verifies
that the host actually exists before adding it to the local table. But
this verification causes other issues. We have received several reports
where people's VPSs got shut down by hosting providers because sending
packets to random LAN hosts is indistinguishable from a slow port scan.
The new check prevents sending random packets to LAN by discarding LAN
IPs sent by Internet hosts (and loopback IPs from LAN and Internet
hosts). The new check also blacklists almost all currently registered
special-purpose networks assigned by IANA to avoid inciting random
responses from services in the LAN.
As another precaution against abuse of the DHT, ports below 1024 are now
considered invalid.
The new package contains three things for now:
- IP network list parsing and matching
- The WSAEMSGSIZE workaround, which is duplicated in p2p/discover and
p2p/discv5.
Port mapper auto discovery used to run immediately after parsing the
--nat flag, giving it a slight performance boost. But this is becoming
inconvenient because we create node.Node for all geth operations
including account management and bare chain interaction. Delay
autodiscovery until the first use instead, which avoids any network
interaction until the node is actually started.
On Windows, UDPConn.ReadFrom returns an error for packets larger
than the receive buffer. The error is not marked temporary, causing
our loop to exit when the first oversized packet arrived. The fix
is to treat this particular error as temporary.
Fixes: #1579, #2087
Updates: #2082
This change makes it possible to add peers without providing their IP
address. The endpoint of the target node is resolved using the discovery
protocol.
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.
If the timeout fired (even just nanoseconds) before the deadline of the
next pending reply, the timer was not rescheduled. The timer would've
been rescheduled anyway once the next packet was sent, but there were
cases where no next packet could ever be sent due to the locking issue
fixed in the previous commit.
As timing-related bugs go, this issue had been present for a long time
and I could never reproduce it. The test added in this commit did
reproduce the issue on about one out of 15 runs.
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.
Lookup calls would spin out of control when network connectivity was
lost. The throttling that was in place only took effect when the table
returned zero results, which doesn't happen very often.
The new throttling should not have a negative impact when the host is
online. Lookups against the network take some time and dials for all
results must complete or hit the cache before a new one is started. This
usually takes longer than four seconds, leaving online lookups
unaffected.
Fixes#1296
As of this commit, we no longer rely on the protocol handler to report
write errors in a timely fashion. When a write fails, shutdown is
initiated immediately and no new writes can start. This will also
prevent new writes from starting after Server.Stop has been called.
