diff options
| -rw-r--r-- | src/net.cpp | 61 |
1 files changed, 34 insertions, 27 deletions
diff --git a/src/net.cpp b/src/net.cpp index 7d6eb31a7c..35a85fad7a 100644 --- a/src/net.cpp +++ b/src/net.cpp @@ -49,6 +49,9 @@ static_assert(MINIUPNPC_API_VERSION >= 10, "miniUPnPc API version >= 10 assumed" // Dump addresses to peers.dat every 15 minutes (900s) static constexpr int DUMP_PEERS_INTERVAL = 15 * 60; +/** Number of DNS seeds to query when the number of connections is low. */ +static constexpr int DNSSEEDS_TO_QUERY_AT_ONCE = 3; + // We add a random period time (0 to 1 seconds) to feeler connections to prevent synchronization. #define FEELER_SLEEP_WINDOW 1 @@ -1508,35 +1511,41 @@ void StopMapPort() void CConnman::ThreadDNSAddressSeed() { - // goal: only query DNS seeds 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) && - (!gArgs.GetBoolArg("-forcednsseed", DEFAULT_FORCEDNSSEED))) { - if (!interruptNet.sleep_for(std::chrono::seconds(11))) - return; + FastRandomContext rng; + std::vector<std::string> seeds = Params().DNSSeeds(); + Shuffle(seeds.begin(), seeds.end(), rng); + int seeds_right_now = 0; // Number of seeds left before testing if we have enough connections + int found = 0; - 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 (gArgs.GetBoolArg("-forcednsseed", DEFAULT_FORCEDNSSEED)) { + // When -forcednsseed is provided, query all. + seeds_right_now = seeds.size(); } - const std::vector<std::string> &vSeeds = Params().DNSSeeds(); - int found = 0; + 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; - LogPrintf("Loading addresses from DNS seeds (could take a while)\n"); + 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; + } + seeds_right_now += DNSSEEDS_TO_QUERY_AT_ONCE; + } - for (const std::string &seed : vSeeds) { if (interruptNet) { return; } + LogPrintf("Loading addresses from DNS seed %s\n", seed); if (HaveNameProxy()) { AddOneShot(seed); } else { @@ -1549,13 +1558,11 @@ void CConnman::ThreadDNSAddressSeed() continue; } unsigned int nMaxIPs = 256; // Limits number of IPs learned from a DNS seed - if (LookupHost(host.c_str(), vIPs, nMaxIPs, true)) - { - for (const CNetAddr& ip : vIPs) - { + if (LookupHost(host.c_str(), vIPs, nMaxIPs, true)) { + for (const CNetAddr& ip : vIPs) { int nOneDay = 24*3600; CAddress addr = CAddress(CService(ip, Params().GetDefaultPort()), requiredServiceBits); - addr.nTime = GetTime() - 3*nOneDay - GetRand(4*nOneDay); // use a random age between 3 and 7 days old + addr.nTime = GetTime() - 3*nOneDay - rng.randrange(4*nOneDay); // use a random age between 3 and 7 days old vAdd.push_back(addr); found++; } @@ -1566,8 +1573,8 @@ void CConnman::ThreadDNSAddressSeed() AddOneShot(seed); } } + --seeds_right_now; } - LogPrintf("%d addresses found from DNS seeds\n", found); } |