Fall back to oneshot for DNS Seeds which don't support filtering.

This allows us to not have to update the chainparams whenever a
DNS Seed changes its filtering support, as well fixes a bug
introduced in 44407100f where returned nodes will never be
attempted.
This commit is contained in:
Matt Corallo 2017-10-19 17:32:45 -04:00
parent 51ae7660b8
commit 62e764219b
3 changed files with 21 additions and 35 deletions

View File

@ -125,12 +125,12 @@ public:
assert(genesis.hashMerkleRoot == uint256S("0x4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b"));
// Note that of those with the service bits flag, most only support a subset of possible options
vSeeds.emplace_back("seed.bitcoin.sipa.be", true); // Pieter Wuille, only supports x1, x5, x9, and xd
vSeeds.emplace_back("dnsseed.bluematt.me", true); // Matt Corallo, only supports x9
vSeeds.emplace_back("dnsseed.bitcoin.dashjr.org", false); // Luke Dashjr
vSeeds.emplace_back("seed.bitcoinstats.com", true); // Christian Decker, supports x1 - xf
vSeeds.emplace_back("seed.bitcoin.jonasschnelli.ch", true); // Jonas Schnelli, only supports x1, x5, x9, and xd
vSeeds.emplace_back("seed.btc.petertodd.org", true); // Peter Todd, only supports x1, x5, x9, and xd
vSeeds.emplace_back("seed.bitcoin.sipa.be"); // Pieter Wuille, only supports x1, x5, x9, and xd
vSeeds.emplace_back("dnsseed.bluematt.me"); // Matt Corallo, only supports x9
vSeeds.emplace_back("dnsseed.bitcoin.dashjr.org"); // Luke Dashjr
vSeeds.emplace_back("seed.bitcoinstats.com"); // Christian Decker, supports x1 - xf
vSeeds.emplace_back("seed.bitcoin.jonasschnelli.ch"); // Jonas Schnelli, only supports x1, x5, x9, and xd
vSeeds.emplace_back("seed.btc.petertodd.org"); // Peter Todd, only supports x1, x5, x9, and xd
base58Prefixes[PUBKEY_ADDRESS] = std::vector<unsigned char>(1,0);
base58Prefixes[SCRIPT_ADDRESS] = std::vector<unsigned char>(1,5);
@ -229,10 +229,10 @@ public:
vFixedSeeds.clear();
vSeeds.clear();
// nodes with support for servicebits filtering should be at the top
vSeeds.emplace_back("testnet-seed.bitcoin.jonasschnelli.ch", true);
vSeeds.emplace_back("seed.tbtc.petertodd.org", true);
vSeeds.emplace_back("seed.testnet.bitcoin.sprovoost.nl", true);
vSeeds.emplace_back("testnet-seed.bluematt.me", true); // Just a static list of stable node(s), only supports x9
vSeeds.emplace_back("testnet-seed.bitcoin.jonasschnelli.ch");
vSeeds.emplace_back("seed.tbtc.petertodd.org");
vSeeds.emplace_back("seed.testnet.bitcoin.sprovoost.nl");
vSeeds.emplace_back("testnet-seed.bluematt.me"); // Just a static list of stable node(s), only supports x9
base58Prefixes[PUBKEY_ADDRESS] = std::vector<unsigned char>(1,111);
base58Prefixes[SCRIPT_ADDRESS] = std::vector<unsigned char>(1,196);

View File

@ -14,12 +14,6 @@
#include <memory>
#include <vector>
struct CDNSSeedData {
std::string host;
bool supportsServiceBitsFiltering;
CDNSSeedData(const std::string &strHost, bool supportsServiceBitsFilteringIn) : host(strHost), supportsServiceBitsFiltering(supportsServiceBitsFilteringIn) {}
};
struct SeedSpec6 {
uint8_t addr[16];
uint16_t port;
@ -71,7 +65,8 @@ public:
bool MineBlocksOnDemand() const { return fMineBlocksOnDemand; }
/** Return the BIP70 network string (main, test or regtest) */
std::string NetworkIDString() const { return strNetworkID; }
const std::vector<CDNSSeedData>& DNSSeeds() const { return vSeeds; }
/** Return the list of hostnames to look up for DNS seeds */
const std::vector<std::string>& DNSSeeds() const { return vSeeds; }
const std::vector<unsigned char>& Base58Prefix(Base58Type type) const { return base58Prefixes[type]; }
const std::string& Bech32HRP() const { return bech32_hrp; }
const std::vector<SeedSpec6>& FixedSeeds() const { return vFixedSeeds; }
@ -85,7 +80,7 @@ protected:
CMessageHeader::MessageStartChars pchMessageStart;
int nDefaultPort;
uint64_t nPruneAfterHeight;
std::vector<CDNSSeedData> vSeeds;
std::vector<std::string> vSeeds;
std::vector<unsigned char> base58Prefixes[MAX_BASE58_TYPES];
std::string bech32_hrp;
std::string strNetworkID;

View File

@ -1577,19 +1577,6 @@ void MapPort(bool)
static std::string GetDNSHost(const CDNSSeedData& data, ServiceFlags* requiredServiceBits)
{
//use default host for non-filter-capable seeds or if we use the default service bits (NODE_NETWORK)
if (!data.supportsServiceBitsFiltering || *requiredServiceBits == NODE_NETWORK) {
*requiredServiceBits = NODE_NETWORK;
return data.host;
}
// See chainparams.cpp, most dnsseeds only support one or two possible servicebits hostnames
return strprintf("x%x.%s", *requiredServiceBits, data.host);
}
void CConnman::ThreadDNSAddressSeed()
{
// goal: only query DNS seeds if address need is acute
@ -1612,22 +1599,22 @@ void CConnman::ThreadDNSAddressSeed()
}
}
const std::vector<CDNSSeedData> &vSeeds = Params().DNSSeeds();
const std::vector<std::string> &vSeeds = Params().DNSSeeds();
int found = 0;
LogPrintf("Loading addresses from DNS seeds (could take a while)\n");
for (const CDNSSeedData &seed : vSeeds) {
for (const std::string &seed : vSeeds) {
if (interruptNet) {
return;
}
if (HaveNameProxy()) {
AddOneShot(seed.host);
AddOneShot(seed);
} else {
std::vector<CNetAddr> vIPs;
std::vector<CAddress> vAdd;
ServiceFlags requiredServiceBits = GetDesirableServiceFlags(NODE_NONE);
std::string host = GetDNSHost(seed, &requiredServiceBits);
std::string host = strprintf("x%x.%s", requiredServiceBits, seed);
CNetAddr resolveSource;
if (!resolveSource.SetInternal(host)) {
continue;
@ -1643,6 +1630,10 @@ void CConnman::ThreadDNSAddressSeed()
found++;
}
addrman.Add(vAdd, resolveSource);
} else {
// We now avoid directly using results from DNS Seeds which do not support service bit filtering,
// instead using them as a oneshot to get nodes with our desired service bits.
AddOneShot(seed);
}
}
}