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-rw-r--r--src/net.cpp59
1 files changed, 51 insertions, 8 deletions
diff --git a/src/net.cpp b/src/net.cpp
index 4cbc43e4d8..eb2c38dd10 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -42,6 +42,9 @@
// Dump addresses to peers.dat and banlist.dat every 15 minutes (900s)
#define DUMP_ADDRESSES_INTERVAL 900
+// We add a random period time (0 to 1 seconds) to feeler connections to prevent synchronization.
+#define FEELER_SLEEP_WINDOW 1
+
#if !defined(HAVE_MSG_NOSIGNAL) && !defined(MSG_NOSIGNAL)
#define MSG_NOSIGNAL 0
#endif
@@ -60,6 +63,7 @@
namespace {
const int MAX_OUTBOUND_CONNECTIONS = 8;
+ const int MAX_FEELER_CONNECTIONS = 1;
struct ListenSocket {
SOCKET socket;
@@ -1016,7 +1020,8 @@ static void AcceptConnection(const ListenSocket& hListenSocket) {
SOCKET hSocket = accept(hListenSocket.socket, (struct sockaddr*)&sockaddr, &len);
CAddress addr;
int nInbound = 0;
- int nMaxInbound = nMaxConnections - MAX_OUTBOUND_CONNECTIONS;
+ int nMaxInbound = nMaxConnections - (MAX_OUTBOUND_CONNECTIONS + MAX_FEELER_CONNECTIONS);
+ assert(nMaxInbound > 0);
if (hSocket != INVALID_SOCKET)
if (!addr.SetSockAddr((const struct sockaddr*)&sockaddr))
@@ -1609,6 +1614,9 @@ void ThreadOpenConnections()
// Initiate network connections
int64_t nStart = GetTime();
+
+ // Minimum time before next feeler connection (in microseconds).
+ int64_t nNextFeeler = PoissonNextSend(nStart*1000*1000, FEELER_INTERVAL);
while (true)
{
ProcessOneShot();
@@ -1646,13 +1654,36 @@ void ThreadOpenConnections()
}
}
}
+ assert(nOutbound <= (MAX_OUTBOUND_CONNECTIONS + MAX_FEELER_CONNECTIONS));
- int64_t nANow = GetAdjustedTime();
+ // Feeler Connections
+ //
+ // Design goals:
+ // * Increase the number of connectable addresses in the tried table.
+ //
+ // Method:
+ // * Choose a random address from new and attempt to connect to it if we can connect
+ // successfully it is added to tried.
+ // * Start attempting feeler connections only after node finishes making outbound
+ // connections.
+ // * Only make a feeler connection once every few minutes.
+ //
+ bool fFeeler = false;
+ if (nOutbound >= MAX_OUTBOUND_CONNECTIONS) {
+ int64_t nTime = GetTimeMicros(); // The current time right now (in microseconds).
+ if (nTime > nNextFeeler) {
+ nNextFeeler = PoissonNextSend(nTime, FEELER_INTERVAL);
+ fFeeler = true;
+ } else {
+ continue;
+ }
+ }
+ int64_t nANow = GetAdjustedTime();
int nTries = 0;
while (true)
{
- CAddrInfo addr = addrman.Select();
+ CAddrInfo addr = addrman.Select(fFeeler);
// if we selected an invalid address, restart
if (!addr.IsValid() || setConnected.count(addr.GetGroup()) || IsLocal(addr))
@@ -1688,8 +1719,17 @@ void ThreadOpenConnections()
break;
}
- if (addrConnect.IsValid())
- OpenNetworkConnection(addrConnect, (int)setConnected.size() >= std::min(nMaxConnections - 1, 2), &grant);
+ if (addrConnect.IsValid()) {
+
+ if (fFeeler) {
+ // Add small amount of random noise before connection to avoid synchronization.
+ int randsleep = GetRandInt(FEELER_SLEEP_WINDOW * 1000);
+ MilliSleep(randsleep);
+ LogPrint("net", "Making feeler connection to %s\n", addrConnect.ToString());
+ }
+
+ OpenNetworkConnection(addrConnect, (int)setConnected.size() >= std::min(nMaxConnections - 1, 2), &grant, NULL, false, fFeeler);
+ }
}
}
@@ -1771,7 +1811,7 @@ void ThreadOpenAddedConnections()
}
// if successful, this moves the passed grant to the constructed node
-bool OpenNetworkConnection(const CAddress& addrConnect, bool fCountFailure, CSemaphoreGrant *grantOutbound, const char *pszDest, bool fOneShot)
+bool OpenNetworkConnection(const CAddress& addrConnect, bool fCountFailure, CSemaphoreGrant *grantOutbound, const char *pszDest, bool fOneShot, bool fFeeler)
{
//
// Initiate outbound network connection
@@ -1795,6 +1835,8 @@ bool OpenNetworkConnection(const CAddress& addrConnect, bool fCountFailure, CSem
pnode->fNetworkNode = true;
if (fOneShot)
pnode->fOneShot = true;
+ if (fFeeler)
+ pnode->fFeeler = true;
return true;
}
@@ -2054,7 +2096,7 @@ void StartNode(boost::thread_group& threadGroup, CScheduler& scheduler)
if (semOutbound == NULL) {
// initialize semaphore
- int nMaxOutbound = std::min(MAX_OUTBOUND_CONNECTIONS, nMaxConnections);
+ int nMaxOutbound = std::min((MAX_OUTBOUND_CONNECTIONS + MAX_FEELER_CONNECTIONS), nMaxConnections);
semOutbound = new CSemaphore(nMaxOutbound);
}
@@ -2096,7 +2138,7 @@ bool StopNode()
LogPrintf("StopNode()\n");
MapPort(false);
if (semOutbound)
- for (int i=0; i<MAX_OUTBOUND_CONNECTIONS; i++)
+ for (int i=0; i<(MAX_OUTBOUND_CONNECTIONS + MAX_FEELER_CONNECTIONS); i++)
semOutbound->post();
if (fAddressesInitialized)
@@ -2437,6 +2479,7 @@ CNode::CNode(SOCKET hSocketIn, const CAddress& addrIn, const std::string& addrNa
fWhitelisted = false;
fOneShot = false;
fClient = false; // set by version message
+ fFeeler = false;
fInbound = fInboundIn;
fNetworkNode = false;
fSuccessfullyConnected = false;