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1 files changed, 49 insertions, 0 deletions

diff --git a/src/btftunnel.h b/src/btftunnel.h
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+// Copyright (c) 2026 Bitflash developers
+// Distributed under the MIT/X11 software license.
+//
+// Transparent anonymous tunnel. Gives the existing CNode a plain local socket
+// while, behind it, a pair of pump threads bridge plaintext <-> echan <->
+// rendezvous. CNode reads/writes normally and never knows its bytes travel
+// end-to-end encrypted through a meeting node (the Itzal `wrap()` pattern).
+//
+// Client side: resolve a `.btf` -> meeting node + service enc key (done by the
+// caller), then BtfClientTunnel connects through the relay, runs the echan
+// handshake, and returns a local SOCKET to hand a new outbound CNode.
+//
+// Service side: after RvServiceRegister pairs us with a client, BtfServiceWrap
+// completes the echan handshake and returns a local SOCKET for an inbound CNode.
+
+#ifndef BITFLASH_BTFTUNNEL_H
+#define BITFLASH_BTFTUNNEL_H
+
+#include "btfrv.h"
+
+#ifdef _WIN32
+#include <winsock2.h>
+typedef SOCKET btf_socket_t;
+#else
+typedef int btf_socket_t;
+#define INVALID_SOCKET (-1)
+#endif
+
+namespace btf
+{
+
+// Initialize (sockets + libsodium). Idempotent.
+bool TunnelInit();
+
+// 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.
+btf_socket_t BtfClientTunnel(const char* meeting_host, unsigned short port,
+                             const unsigned char target_pubkey[32],
+                             const unsigned char service_enc_pub[32]);
+
+// Service: wrap an already-paired rendezvous socket (from RvServiceRegister)
+// with echan using my static x25519 secret, returning a local plaintext SOCKET
+// for an inbound CNode. Consumes `rv` (closed when the tunnel tears down).
+btf_socket_t BtfServiceWrap(RvSocket rv, const unsigned char my_enc_sk[32]);
+
+} // namespace btf
+
+#endif