Merge #17164: p2p: Avoid allocating memory for addrKnown where we don't need it

b6d2183858975abc961207c125c15791e531edcc Minor refactoring to remove implied m_addr_relay_peer. (User)
a552e8477c5bcd22a5457f4f73a2fd6db8acd2c2 added asserts to check m_addr_known when it's used (User)
090b75c14be6b9ba2efe38a17d141c6e6af575cb p2p: Avoid allocating memory for addrKnown where we don't need it (User)

Pull request description:

  We should allocate memory for addrKnown filter only for those peers which are expected to participate in address relay.

  Currently, we do it for all peers (including SPV and block-relay-only),  which results in extra RAM where it's not needed.

  Upd:
  In future, we would still allow SPVs to ask for addrs, so allocation still will be done by default.
  However, they will be able to opt-out via [this proposal](https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2019-October/017428.html) and then we could save some more memory.
  This PR still saves memory for block-relay-only peers immediately after merging.

Top commit has no ACKs.

Tree-SHA512: e84d93b2615556d466f5ca0e543580fde763911a3bfea3127c493ddfaba8f05c8605cb94ff795d165af542b594400995a2c51338185c298581408687e7812463

1 files changed, 6 insertions, 5 deletions

diff --git a/src/net.h b/src/net.h
index 1bbcc89478..1e5f1c3f09 100644
--- a/src/net.h
+++ b/src/net.h
@@ -776,13 +776,12 @@ public:
 
     // flood relay
     std::vector<CAddress> vAddrToSend;
-    CRollingBloomFilter addrKnown;
+    const std::unique_ptr<CRollingBloomFilter> m_addr_known;
     bool fGetAddr{false};
     int64_t nNextAddrSend GUARDED_BY(cs_sendProcessing){0};
     int64_t nNextLocalAddrSend GUARDED_BY(cs_sendProcessing){0};
 
-    const bool m_addr_relay_peer;
-    bool IsAddrRelayPeer() const { return m_addr_relay_peer; }
+    bool IsAddrRelayPeer() const { return m_addr_known != nullptr; }
 
     // List of block ids we still have announce.
     // There is no final sorting before sending, as they are always sent immediately
@@ -931,7 +930,8 @@ public:
 
     void AddAddressKnown(const CAddress& _addr)
     {
-        addrKnown.insert(_addr.GetKey());
+        assert(m_addr_known);
+        m_addr_known->insert(_addr.GetKey());
     }
 
     void PushAddress(const CAddress& _addr, FastRandomContext &insecure_rand)
@@ -939,7 +939,8 @@ public:
         // Known checking here is only to save space from duplicates.
         // SendMessages will filter it again for knowns that were added
         // after addresses were pushed.
-        if (_addr.IsValid() && !addrKnown.contains(_addr.GetKey())) {
+        assert(m_addr_known);
+        if (_addr.IsValid() && !m_addr_known->contains(_addr.GetKey())) {
             if (vAddrToSend.size() >= MAX_ADDR_TO_SEND) {
                 vAddrToSend[insecure_rand.randrange(vAddrToSend.size())] = _addr;
             } else {