Net: Fixed a race condition when disabling the network.

This change addresses a race condition where setnetworkactive=false wouldn't always disconnect all peers.

Before this change, the following could happen:
1. Thread A -- Begins connecting to a node.
2. Thread B -- Sets kNetworkActive=false and disconnects connected nodes.
3. Thread A -- Finishes connecting and adds node to list of connected nodes.

The node that was connected from Thread A remains connected and active,
even though kNetworkActive=false.

To fix the race, disconnections when kNetworkActive=false are now handled in the main network loop.

fixes #13038
This commit is contained in:
lmanners 2018-05-10 18:23:22 +02:00
parent 1c58250350
commit 793290f940

View file

@ -1163,6 +1163,17 @@ void CConnman::ThreadSocketHandler()
//
{
LOCK(cs_vNodes);
if (!fNetworkActive) {
// Disconnect any connected nodes
for (CNode* pnode : vNodes) {
if (!pnode->fDisconnect) {
LogPrint(BCLog::NET, "Network not active, dropping peer=%d\n", pnode->GetId());
pnode->fDisconnect = true;
}
}
}
// Disconnect unused nodes
std::vector<CNode*> vNodesCopy = vNodes;
for (CNode* pnode : vNodesCopy)
@ -2198,14 +2209,6 @@ void CConnman::SetNetworkActive(bool active)
fNetworkActive = active;
if (!fNetworkActive) {
LOCK(cs_vNodes);
// Close sockets to all nodes
for (CNode* pnode : vNodes) {
pnode->CloseSocketDisconnect();
}
}
uiInterface.NotifyNetworkActiveChanged(fNetworkActive);
}