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-rw-r--r--src/main.cpp28
-rw-r--r--src/version.h3
2 files changed, 28 insertions, 3 deletions
diff --git a/src/main.cpp b/src/main.cpp
index b9c9db7a62..fbe9232ac0 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -2652,6 +2652,23 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
else if (strCommand == "ping")
{
+ if (pfrom->nVersion > BIP0031_VERSION)
+ {
+ uint64 nonce = 0;
+ vRecv >> nonce;
+ // Echo the message back with the nonce. This allows for two useful features:
+ //
+ // 1) A remote node can quickly check if the connection is operational
+ // 2) Remote nodes can measure the latency of the network thread. If this node
+ // is overloaded it won't respond to pings quickly and the remote node can
+ // avoid sending us more work, like chain download requests.
+ //
+ // The nonce stops the remote getting confused between different pings: without
+ // it, if the remote node sends a ping once per second and this node takes 5
+ // seconds to respond to each, the 5th ping the remote sends would appear to
+ // return very quickly.
+ pfrom->PushMessage("pong", nonce);
+ }
}
@@ -2814,9 +2831,14 @@ bool SendMessages(CNode* pto, bool fSendTrickle)
if (pto->nVersion == 0)
return true;
- // Keep-alive ping
- if (pto->nLastSend && GetTime() - pto->nLastSend > 30 * 60 && pto->vSend.empty())
- pto->PushMessage("ping");
+ // Keep-alive ping. We send a nonce of zero because we don't use it anywhere
+ // right now.
+ if (pto->nLastSend && GetTime() - pto->nLastSend > 30 * 60 && pto->vSend.empty()) {
+ if (pto->nVersion > BIP0031_VERSION)
+ pto->PushMessage("ping", 0);
+ else
+ pto->PushMessage("ping");
+ }
// Resend wallet transactions that haven't gotten in a block yet
ResendWalletTransactions();
diff --git a/src/version.h b/src/version.h
index c93b28fb7d..e0e216aad4 100644
--- a/src/version.h
+++ b/src/version.h
@@ -11,4 +11,7 @@ extern const std::string CLIENT_BUILD;
extern const std::string CLIENT_DATE;
extern const int CLIENT_VERSION;
+// BIP 0031, pong message, is enabled for all versions AFTER this one
+const int BIP0031_VERSION = 60000;
+
#endif