Replace automatic bans with discouragement filter

This patch improves performance and resource usage around IP
addresses that are banned for misbehavior. They're already not
actually banned, as connections from them are still allowed,
but they are preferred for eviction if the inbound connection
slots are full.

Stop treating these like manually banned IP ranges, and instead
just keep them in a rolling Bloom filter of misbehaving nodes,
which isn't persisted to disk or exposed through the ban
framework. The effect remains the same: preferred for eviction,
avoided for outgoing connections, and not relayed to other peers.

Also change the name of this mechanism to better reflect reality;
they're not banned, just discouraged.

Contains release notes and several interface improvements by
John Newbery.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/init.cpp b/src/init.cpp
index 35e211a9d7..37e4c1e77c 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -430,8 +430,8 @@ void SetupServerArgs(NodeContext& node)
 
     gArgs.AddArg("-addnode=<ip>", "Add a node to connect to and attempt to keep the connection open (see the `addnode` RPC command help for more info). This option can be specified multiple times to add multiple nodes.", ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY, OptionsCategory::CONNECTION);
     gArgs.AddArg("-asmap=<file>", strprintf("Specify asn mapping used for bucketing of the peers (default: %s). Relative paths will be prefixed by the net-specific datadir location.", DEFAULT_ASMAP_FILENAME), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
-    gArgs.AddArg("-banscore=<n>", strprintf("Threshold for disconnecting misbehaving peers (default: %u)", DEFAULT_BANSCORE_THRESHOLD), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
-    gArgs.AddArg("-bantime=<n>", strprintf("Number of seconds to keep misbehaving peers from reconnecting (default: %u)", DEFAULT_MISBEHAVING_BANTIME), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
+    gArgs.AddArg("-banscore=<n>", strprintf("Threshold for disconnecting and discouraging misbehaving peers (default: %u)", DEFAULT_BANSCORE_THRESHOLD), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
+    gArgs.AddArg("-bantime=<n>", strprintf("Default duration (in seconds) of manually configured bans (default: %u)", DEFAULT_MISBEHAVING_BANTIME), ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);
     gArgs.AddArg("-bind=<addr>", "Bind to given address and always listen on it. Use [host]:port notation for IPv6", ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY, OptionsCategory::CONNECTION);
     gArgs.AddArg("-connect=<ip>", "Connect only to the specified node; -noconnect disables automatic connections (the rules for this peer are the same as for -addnode). This option can be specified multiple times to connect to multiple nodes.", ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY, OptionsCategory::CONNECTION);
     gArgs.AddArg("-discover", "Discover own IP addresses (default: 1 when listening and no -externalip or -proxy)", ArgsManager::ALLOW_ANY, OptionsCategory::CONNECTION);