A risk exists where a malicious DNS seeder eclipses a node by returning an enormous number of IP addresses. In this commit we mitigate this risk by limiting the number of IP addresses addrman learns to 256 per DNS seeder.
GitHub-Pull: #12626
Rebased-From: 46e7f80
This allows us to not have to update the chainparams whenever a
DNS Seed changes its filtering support, as well fixes a bug
introduced in 44407100f where returned nodes will never be
attempted.
44407100f broke inserting entries into addrman from static seeds
(as well as dnsseeds which did not support service bits). Static
seeds were already being filtered by UA for 0.13.1+ (ie
NODE_WITNESS), so simply changing the default service bits to
include NODE_WITNESS (and updating docs appropriately) is
sufficient.
For DNS Seeds, we will later fix by falling back to oneshot if a
seed does not support filtering.
We use select in ConnectSocketDirectly, so this check needs to happen before
that.
IsSelectableSocket will not be relevant after upcoming changes to remove select.
We should generally avoid writing to debug.log unconditionally for
inbound peers which misbehave (the peer being about to be banned
being an exception, since they cannot do this twice).
To avoid removing logs for outbound peers, a new log is added to
notify users when a new outbound peer is connected which mimics
the version print.
If our tip hasn't updated in a while, that may be because our peers are
not relaying blocks to us that we would consider valid. Allow connection
to an additional outbound peer in that circumstance.
Also, periodically check to see if we are exceeding our target number of
outbound peers, and disconnect the one which has least recently
announced a new block to us (choosing the newest such peer in the case
of tie).
Adds HasAllRelevantServices and GetRelevantServices, which check
for NETWORK|WITNESS.
This changes the following:
* Removes nRelevantServices from CConnman, disconnecting it a bit
more from protocol-level logic.
* Replaces our sometimes-connect-to-!WITNESS-nodes logic with
simply always requiring WITNESS|NETWORK for outbound non-feeler
connections (feelers still only require NETWORK).
* This has the added benefit of removing nServicesExpected from
CNode - instead letting net_processing's VERSION message
handling simply check HasAllRelevantServices.
* This implies we believe WITNESS nodes to continue to be a
significant majority of nodes on the network, but also because
we cannot sync properly from !WITNESS nodes, it is strange to
continue using our valuable outbound slots on them.
* In order to prevent this change from preventing connection to
-connect= nodes which have !WITNESS, -connect nodes are now
given the "addnode" flag. This also allows outbound connections
to !NODE_NETWORK nodes for -connect nodes (which was already true
of addnodes).
* Has the (somewhat unintended) consequence of changing one of the
eviction metrics from the same
sometimes-connect-to-!WITNESS-nodes metric to requiring
HasRelevantServices.
This should make NODE_NETWORK_LIMITED much simpler to implement.
This was added in order to help OpenNetworkConnection avoid creating a
connection that it would end up aborting. It was necessary because resolving
was done as part of the connection process.
Now that resolving is separated from connecting, this case is detected before
the connection is attempted.
ConnectSocketByName handled resolves as necessary, obscuring the connection
process. With them separated, each can be handled asynchronously.
Also, since proxies must be considered now anyway, go ahead and eliminate the
ConnectSocket wrapper and use ConnectSocketDirectly... directly.
There are a few too many edge-cases here to make this a scripted diff.
The following commits will move a few functions into PeerLogicValidation, where
the local connman instance can be used. This change prepares for that usage.
When running test_bitcoin under Valgrind I found the following issue:
```
$ valgrind src/test/test_bitcoin
...
==10465== Use of uninitialised value of size 8
==10465== at 0x6D09B61: ??? (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.21)
==10465== by 0x6D0B1BB: std::ostreambuf_iterator<char, std::char_traits<char> > std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::_M_insert_int<unsigned long>(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, unsigned long) const (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.21)
==10465== by 0x6D0B36C: std::num_put<char, std::ostreambuf_iterator<char, std::char_traits<char> > >::do_put(std::ostreambuf_iterator<char, std::char_traits<char> >, std::ios_base&, char, unsigned long) const (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.21)
==10465== by 0x6D17699: std::ostream& std::ostream::_M_insert<unsigned long>(unsigned long) (in /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.21)
==10465== by 0x4CAAD7: operator<< (ostream:171)
==10465== by 0x4CAAD7: formatValue<ServiceFlags> (tinyformat.h:345)
==10465== by 0x4CAAD7: void tinyformat::detail::FormatArg::formatImpl<ServiceFlags>(std::ostream&, char const*, char const*, int, void const*) (tinyformat.h:523)
==10465== by 0x1924D4: format (tinyformat.h:510)
==10465== by 0x1924D4: tinyformat::detail::formatImpl(std::ostream&, char const*, tinyformat::detail::FormatArg const*, int) (tinyformat.h:803)
==10465== by 0x553A55: vformat (tinyformat.h:947)
==10465== by 0x553A55: format<ServiceFlags> (tinyformat.h:957)
==10465== by 0x553A55: std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > tinyformat::format<ServiceFlags>(char const*, ServiceFlags const&) (tinyformat.h:966)
==10465== by 0x54C952: getnetworkinfo(JSONRPCRequest const&) (net.cpp:462)
==10465== by 0x28EDB5: CallRPC(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >) (rpc_tests.cpp:31)
==10465== by 0x293947: rpc_tests::rpc_togglenetwork::test_method() (rpc_tests.cpp:88)
==10465== by 0x2950E5: rpc_tests::rpc_togglenetwork_invoker() (rpc_tests.cpp:84)
==10465== by 0x182496: invoke<void (*)()> (callback.hpp:56)
==10465== by 0x182496: boost::unit_test::ut_detail::callback0_impl_t<boost::unit_test::ut_detail::unused, void (*)()>::invoke() (callback.hpp:89)
...
```
The read of the uninitialized variable nLocalServices is triggered by g_connman->GetLocalServices()
in getnetworkinfo(const JSONRPCRequest& request) (net.cpp:462):
```c++
UniValue getnetworkinfo(const JSONRPCRequest& request)
{
...
if(g_connman)
obj.push_back(Pair("localservices", strprintf("%016x", g_connman->GetLocalServices())));
...
}
```
The reason for the uninitialized nLocalServices is that CConnman::Start(...) is not called
by the tests, and hence the initialization normally performed by CConnman::Start(...) is
not done.
This commit adds a method Init(const Options& connOptions) which is called by both the
constructor and CConnman::Start(...). This method initializes nLocalServices and the other
relevant values from the supplied Options object.
Identified with `cppcheck --enable=unusedFunction .`.
- GetSendBufferSize()'s last use removed in
991955ee81
- SetPort()'s last use removed in
7e195e8459
- GetfLargeWorkInvalidChainFound() was introduced in
e3ba0ef956 and never used
Part of a series of changes to clean up the instantiation of connman
by decoupling the command line arguments.
We also now abort with an error when explicit binds are set with
-listen=0.
Jianping Wu