Bring main onto the line this project actually ships

main had drifted to a history with no ancestor in common with the tree we
build and deploy. It sat at be63e83 (2026-08-09) with 28 commits; the shipped
line, deploy/soak-2026-08-21, had 383. The two shared nothing -- git
merge-base returns no result at all -- so anyone cloning this repository
landed on a default branch that was neither current nor related to the
running node.

The 28 commits on main were audited before this merge: every one is already
present in the tree by content, including the two that are hardest to see
because they were rewritten afterwards -- the payout reorg-safety work
(PayoutBlockStillOnChain, since evolved to re-check on every retry rather
than once at maturity) and the nostr relay certificate verification
(SSL_set1_host, now with a Windows root-store path). Nothing on main is lost
by this merge.

Recorded as a merge rather than a force-push: main only ever moves forward,
its old history stays reachable as the first parent, and this is revertible.
The tree is taken wholesale from the merged branch, so main's content is now
exactly what was built and tested.

What this brings onto main:

- compactblock: BIP152-style compact block relay ported from upstream 1.2.23,
  primitives and unit test only, with the RAND_bytes failure path closed and
  the reconstruction allocation bounded.
- upstream/main 17741d9: isolated testnet parameters and genesis, optional
  2 MB large pages for RandomX. Mainnet genesis verified byte-identical
  through upstream's BuildGenesisBlock() refactor.
- deploy: every image built on bookworm so binaries run on Debian 12, and the
  container build now honours the RandomX and libsecp256k1 pins it had been
  silently ignoring since before 1.2.15.

Gates at this tree: 15/15 selftests, compactblock's 17 checks, consensus
constants unchanged against e4f898c apart from the pre-existing
MAX_BLOCK_SIZE_GEN, mainnet genesis intact, money-log check ok.

1 files changed, 23 insertions, 2 deletions

diff --git a/src/btftunnel.h b/src/btftunnel.h
index 24a7509..3cc87cd 100644
--- a/src/btftunnel.h
+++ b/src/btftunnel.h
@@ -36,12 +36,33 @@ namespace btf
 // Initialize (sockets + libsodium). Idempotent.
 bool TunnelInit();
 
+// Which stage of BtfClientTunnel failed. INVALID_SOCKET alone says only "no
+// tunnel"; a caller that then guesses at causes in its log line sends whoever
+// reads it to the wrong component (issue #17: "relay unreachable or pool not
+// listening" blamed two healthy parts). The stage is what this side actually
+// knows -- report that.
+enum TunnelFail
+{
+    TUNNEL_FAIL_NONE = 0,
+    TUNNEL_FAIL_INIT,      // local socket/crypto init failed
+    TUNNEL_FAIL_DIAL,      // TCP connect to the meeting node failed
+    TUNNEL_FAIL_REFUSED,   // relay reachable, but no service registered under the pubkey
+    TUNNEL_FAIL_PAIR,      // relay connection died before pairing completed
+    TUNNEL_FAIL_HANDSHAKE, // end-to-end channel handshake failed
+    TUNNEL_FAIL_LOCAL,     // local pump plumbing (socket pair / threads) failed
+};
+
+// Short description of a TunnelFail for log lines.
+const char* TunnelFailText(TunnelFail f);
+
 // Client: dial the service registered under `target_pubkey` at the meeting node
 // (host:port), box to its static x25519 `service_enc_pub`, and return a local
-// plaintext SOCKET tunneled end-to-end to the service. INVALID_SOCKET on error.
+// plaintext SOCKET tunneled end-to-end to the service. INVALID_SOCKET on error
+// -- with `pFail`, if given, naming the stage that failed.
 btf_socket_t BtfClientTunnel(const char* meeting_host, unsigned short port,
                              const unsigned char target_pubkey[32],
-                             const unsigned char service_enc_pub[32]);
+                             const unsigned char service_enc_pub[32],
+                             TunnelFail* pFail = 0);
 
 // Service: wrap an already-paired rendezvous socket (RvServiceRegister followed
 // by RvServiceWaitPaired -- the pairing byte MUST already be consumed) with