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, 18 deletions

diff --git a/src/main_gui.cpp b/src/main_gui.cpp
index edc772d..842b0d5 100644
--- a/src/main_gui.cpp
+++ b/src/main_gui.cpp
@@ -58,7 +58,6 @@ static void PrintUsage()
     printf("  /connectbtf=PEER_BTF_ADDRESS\n");
     printf("  /rvrelay=HOST:PORT\n");
     printf("  /announcerelay=HOST:PORT\n");
-    printf("  /port=N                  (P2P listen port, default 8433)\n");
     printf("\n");
     printf("Each option also accepts '-' instead of '/'.\n");
 }
@@ -114,23 +113,6 @@ static void ParseStartupArguments(int argc, char* argv[])
     string announceRelay = argval2(argc, argv, "/announcerelay", "-announcerelay");
     if (!announceRelay.empty())
         strBtfAnnounceRelay = announceRelay;
-
-    // net.cpp has claimed nListenPort was "tunable via /port" since it was
-    // written, but nothing ever read the option. Without it a second node
-    // cannot start on a machine that already runs one -- which is exactly what
-    // testing peer exchange needs.
-    string strPort = argval2(argc, argv, "/port", "-port");
-    if (!strPort.empty())
-    {
-        int nPort = atoi(strPort.c_str());
-        if (nPort <= 0 || nPort > 65535)
-            fprintf(stderr, "Ignoring /port=%s: not a port number\n", strPort.c_str());
-        else
-        {
-            nListenPort = htons((unsigned short)nPort);
-            addrLocalHost.port = nListenPort;  // or we advertise a port we never bound
-        }
-    }
 }
 
 int main(int argc, char* argv[])