Remove peer exchange from main; it was merged unreviewed (#27)

PR #25 was opened, reviewed and approved as a single-file change to net.cpp:
the .btf peer cache, +169/-0. I then pushed peer exchange and a /port option
onto that same branch while the PR was open, which silently widened it to six
files. The merge carried all of it in.

Nothing about the peer exchange had been validated. Its two-node test never
completed -- node B could not dial node A at all -- so what landed on main is
unproven network protocol code that no one agreed to take.

This restores main to what #25 actually described. The peer cache stays, with
its runtime numbers (36.3s to 2.1s to first peer). #26 stays. What comes out:

- the "btfpeers" message, both directions
- BtfPexCollect / BtfPexAccept and the per-message caps
- CNode::nLastPexRecv
- the `desc` field on the cached peer record
- BtfLocalDescriptor / BtfSecpContext
- /port

Peer exchange returns as its own pull request once its test passes. The /port
option is worth having on its own -- two nodes cannot share a machine without
it, which is what blocked the test -- and should go up separately rather than
ride along again.

Release v1.2.2 is unaffected: it was built from ba2de82, before either merge.

1 files changed, 0 insertions, 31 deletions

diff --git a/src/main.cpp b/src/main.cpp
index bb317d2..a75bf54 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1877,14 +1877,6 @@ bool ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
             pfrom->PushMessage("getblocks", CBlockLocator(pindexBest), uint256(0));
         }
 
-        // Introduce ourselves and hand over the .btf peers that answered us.
-        // Everything in here is self-certifying, so this is safe to send to a
-        // node we know nothing about, and safe for it to act on.
-        vector<string> vPexOut;
-        BtfPexCollect(vPexOut);
-        if (!vPexOut.empty())
-            pfrom->PushMessage("btfpeers", vPexOut);
-
         if (LogAcceptsCategory("net")) printf("version addrMe = %s\n", addrMe.ToString().c_str());
     }
 
@@ -1896,29 +1888,6 @@ bool ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv)
     }
 
 
-    else if (strCommand == "btfpeers")
-    {
-        // Peer exchange. Nothing here is taken on trust: BtfPexAccept checks
-        // every descriptor's signature against the key its .btf address
-        // decodes to, and drops the rest.
-        int64 nNow = GetTime();
-        if (nNow - pfrom->nLastPexRecv < PEX_MIN_INTERVAL)
-        {
-            if (LogAcceptsCategory("net"))
-                printf("btfpeers: ignoring, %s is sending them too fast\n",
-                       pfrom->addr.ToString().c_str());
-            return true;
-        }
-        pfrom->nLastPexRecv = nNow;
-
-        vector<string> vDesc;
-        vRecv >> vDesc;
-        int nKept = BtfPexAccept(vDesc);
-        LogPrint("net", "btfpeers: kept %d of %zu descriptor(s) from %s\n",
-                 nKept, vDesc.size(), pfrom->addr.ToString().c_str());
-    }
-
-
     else if (strCommand == "inv")
     {
         vector<CInv> vInv;