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-rw-r--r--src/net.cpp87
1 files changed, 65 insertions, 22 deletions
diff --git a/src/net.cpp b/src/net.cpp
index 97b80b50e2..707412bb32 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -16,6 +16,7 @@
#include <crypto/sha256.h>
#include <netbase.h>
#include <net_permissions.h>
+#include <protocol.h>
#include <random.h>
#include <scheduler.h>
#include <ui_interface.h>
@@ -51,6 +52,12 @@ static constexpr std::chrono::minutes DUMP_PEERS_INTERVAL{15};
/** Number of DNS seeds to query when the number of connections is low. */
static constexpr int DNSSEEDS_TO_QUERY_AT_ONCE = 3;
+/** How long to delay before querying DNS seeds
+ */
+static constexpr std::chrono::seconds DNSSEEDS_DELAY_FEW_PEERS{11}; // 11sec
+static constexpr std::chrono::seconds DNSSEEDS_DELAY_MANY_PEERS{300}; // 5min
+static constexpr int DNSSEEDS_DELAY_PEER_THRESHOLD = 1000; // "many" vs "few" peers -- you should only get this many if you've been on the live network
+
// We add a random period time (0 to 1 seconds) to feeler connections to prevent synchronization.
#define FEELER_SLEEP_WINDOW 1
@@ -631,14 +638,14 @@ int CNode::GetSendVersion() const
int V1TransportDeserializer::readHeader(const char *pch, unsigned int nBytes)
{
// copy data to temporary parsing buffer
- unsigned int nRemaining = 24 - nHdrPos;
+ unsigned int nRemaining = CMessageHeader::HEADER_SIZE - nHdrPos;
unsigned int nCopy = std::min(nRemaining, nBytes);
memcpy(&hdrbuf[nHdrPos], pch, nCopy);
nHdrPos += nCopy;
// if header incomplete, exit
- if (nHdrPos < 24)
+ if (nHdrPos < CMessageHeader::HEADER_SIZE)
return nCopy;
// deserialize to CMessageHeader
@@ -1454,7 +1461,7 @@ void CConnman::ThreadSocketHandler()
void CConnman::WakeMessageHandler()
{
{
- std::lock_guard<std::mutex> lock(mutexMsgProc);
+ LOCK(mutexMsgProc);
fMsgProcWake = true;
}
condMsgProc.notify_one();
@@ -1586,31 +1593,67 @@ void CConnman::ThreadDNSAddressSeed()
if (gArgs.GetBoolArg("-forcednsseed", DEFAULT_FORCEDNSSEED)) {
// When -forcednsseed is provided, query all.
seeds_right_now = seeds.size();
+ } else if (addrman.size() == 0) {
+ // If we have no known peers, query all.
+ seeds_right_now = seeds.size();
}
+ // goal: only query DNS seed if address need is acute
+ // * If we have a reasonable number of peers in addrman, spend
+ // some time trying them first. This improves user privacy by
+ // creating fewer identifying DNS requests, reduces trust by
+ // giving seeds less influence on the network topology, and
+ // reduces traffic to the seeds.
+ // * When querying DNS seeds query a few at once, this ensures
+ // that we don't give DNS seeds the ability to eclipse nodes
+ // that query them.
+ // * If we continue having problems, eventually query all the
+ // DNS seeds, and if that fails too, also try the fixed seeds.
+ // (done in ThreadOpenConnections)
+ const std::chrono::seconds seeds_wait_time = (addrman.size() >= DNSSEEDS_DELAY_PEER_THRESHOLD ? DNSSEEDS_DELAY_MANY_PEERS : DNSSEEDS_DELAY_FEW_PEERS);
+
for (const std::string& seed : seeds) {
- // goal: only query DNS seed if address need is acute
- // Avoiding DNS seeds when we don't need them improves user privacy by
- // creating fewer identifying DNS requests, reduces trust by giving seeds
- // less influence on the network topology, and reduces traffic to the seeds.
- if (addrman.size() > 0 && seeds_right_now == 0) {
- if (!interruptNet.sleep_for(std::chrono::seconds(11))) return;
+ if (seeds_right_now == 0) {
+ seeds_right_now += DNSSEEDS_TO_QUERY_AT_ONCE;
- LOCK(cs_vNodes);
- int nRelevant = 0;
- for (const CNode* pnode : vNodes) {
- nRelevant += pnode->fSuccessfullyConnected && !pnode->fFeeler && !pnode->fOneShot && !pnode->m_manual_connection && !pnode->fInbound;
- }
- if (nRelevant >= 2) {
- LogPrintf("P2P peers available. Skipped DNS seeding.\n");
- return;
+ if (addrman.size() > 0) {
+ LogPrintf("Waiting %d seconds before querying DNS seeds.\n", seeds_wait_time.count());
+ std::chrono::seconds to_wait = seeds_wait_time;
+ while (to_wait.count() > 0) {
+ std::chrono::seconds w = std::min(DNSSEEDS_DELAY_FEW_PEERS, to_wait);
+ if (!interruptNet.sleep_for(w)) return;
+ to_wait -= w;
+
+ int nRelevant = 0;
+ {
+ LOCK(cs_vNodes);
+ for (const CNode* pnode : vNodes) {
+ nRelevant += pnode->fSuccessfullyConnected && !pnode->fFeeler && !pnode->fOneShot && !pnode->m_manual_connection && !pnode->fInbound;
+ }
+ }
+ if (nRelevant >= 2) {
+ if (found > 0) {
+ LogPrintf("%d addresses found from DNS seeds\n", found);
+ LogPrintf("P2P peers available. Finished DNS seeding.\n");
+ } else {
+ LogPrintf("P2P peers available. Skipped DNS seeding.\n");
+ }
+ return;
+ }
+ }
}
- seeds_right_now += DNSSEEDS_TO_QUERY_AT_ONCE;
}
- if (interruptNet) {
- return;
+ if (interruptNet) return;
+
+ // hold off on querying seeds if p2p network deactivated
+ if (!fNetworkActive) {
+ LogPrintf("Waiting for network to be reactivated before querying DNS seeds.\n");
+ do {
+ if (!interruptNet.sleep_for(std::chrono::seconds{1})) return;
+ } while (!fNetworkActive);
}
+
LogPrintf("Loading addresses from DNS seed %s\n", seed);
if (HaveNameProxy()) {
AddOneShot(seed);
@@ -2057,7 +2100,7 @@ void CConnman::ThreadMessageHandler()
WAIT_LOCK(mutexMsgProc, lock);
if (!fMoreWork) {
- condMsgProc.wait_until(lock, std::chrono::steady_clock::now() + std::chrono::milliseconds(100), [this] { return fMsgProcWake; });
+ condMsgProc.wait_until(lock, std::chrono::steady_clock::now() + std::chrono::milliseconds(100), [this]() EXCLUSIVE_LOCKS_REQUIRED(mutexMsgProc) { return fMsgProcWake; });
}
fMsgProcWake = false;
}
@@ -2365,7 +2408,7 @@ static CNetCleanup instance_of_cnetcleanup;
void CConnman::Interrupt()
{
{
- std::lock_guard<std::mutex> lock(mutexMsgProc);
+ LOCK(mutexMsgProc);
flagInterruptMsgProc = true;
}
condMsgProc.notify_all();