net: Deserialize hardcoded seeds from BIP155 blob

Switch from IPv6 slot-based format to more compact and flexible BIP155
format.

src/chainparams.cpp

@@ -134,7 +134,7 @@ public:
 
         bech32_hrp = "bc";
 
-        vFixedSeeds = std::vector<SeedSpec6>(std::begin(pnSeed6_main), std::end(pnSeed6_main));
+        vFixedSeeds = std::vector<uint8_t>(std::begin(chainparams_seed_main), std::end(chainparams_seed_main));
 
         fDefaultConsistencyChecks = false;
         fRequireStandard = true;
@@ -239,7 +239,7 @@ public:
 
         bech32_hrp = "tb";
 
-        vFixedSeeds = std::vector<SeedSpec6>(std::begin(pnSeed6_test), std::end(pnSeed6_test));
+        vFixedSeeds = std::vector<uint8_t>(std::begin(chainparams_seed_test), std::end(chainparams_seed_test));
 
         fDefaultConsistencyChecks = false;
         fRequireStandard = false;

src/chainparams.h

@@ -14,11 +14,6 @@
 #include <memory>
 #include <vector>
 
-struct SeedSpec6 {
-    uint8_t addr[16];
-    uint16_t port;
-};
-
 typedef std::map<int, uint256> MapCheckpoints;
 
 struct CCheckpointData {
@@ -108,7 +103,7 @@ public:
     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; }
+    const std::vector<uint8_t>& FixedSeeds() const { return vFixedSeeds; }
     const CCheckpointData& Checkpoints() const { return checkpointData; }
 
     //! Get allowed assumeutxo configuration.
@@ -130,7 +125,7 @@ protected:
     std::string bech32_hrp;
     std::string strNetworkID;
     CBlock genesis;
-    std::vector<SeedSpec6> vFixedSeeds;
+    std::vector<uint8_t> vFixedSeeds;
     bool fDefaultConsistencyChecks;
     bool fRequireStandard;
     bool m_is_test_chain;

src/net.cpp

@@ -141,8 +141,8 @@ bool GetLocal(CService& addr, const CNetAddr *paddrPeer)
     return nBestScore >= 0;
 }
 
-//! Convert the pnSeed6 array into usable address objects.
-static std::vector<CAddress> convertSeed6(const std::vector<SeedSpec6> &vSeedsIn)
+//! Convert the serialized seeds into usable address objects.
+static std::vector<CAddress> ConvertSeeds(const std::vector<uint8_t> &vSeedsIn)
 {
     // It'll only connect to one or two seed nodes because once it connects,
     // it'll get a pile of addresses with newer timestamps.
@@ -150,13 +150,14 @@ static std::vector<CAddress> convertSeed6(const std::vector<SeedSpec6> &vSeedsIn
     // weeks ago.
     const int64_t nOneWeek = 7*24*60*60;
     std::vector<CAddress> vSeedsOut;
-    vSeedsOut.reserve(vSeedsIn.size());
     FastRandomContext rng;
-    for (const auto& seed_in : vSeedsIn) {
-        struct in6_addr ip;
-        memcpy(&ip, seed_in.addr, sizeof(ip));
-        CAddress addr(CService(ip, seed_in.port), GetDesirableServiceFlags(NODE_NONE));
+    CDataStream s(vSeedsIn, SER_NETWORK, PROTOCOL_VERSION | ADDRV2_FORMAT);
+    while (!s.eof()) {
+        CService endpoint;
+        s >> endpoint;
+        CAddress addr{endpoint, GetDesirableServiceFlags(NODE_NONE)};
         addr.nTime = GetTime() - rng.randrange(nOneWeek) - nOneWeek;
+        LogPrint(BCLog::NET, "Added hardcoded seed: %s\n", addr.ToString());
         vSeedsOut.push_back(addr);
     }
     return vSeedsOut;
@@ -1840,7 +1841,7 @@ void CConnman::ThreadOpenConnections(const std::vector<std::string> connect)
             if (add_fixed_seeds_now) {
                 CNetAddr local;
                 local.SetInternal("fixedseeds");
-                addrman.Add(convertSeed6(Params().FixedSeeds()), local);
+                addrman.Add(ConvertSeeds(Params().FixedSeeds()), local);
                 add_fixed_seeds = false;
             }
         }