net: Automatically create hidden service, listen on Tor

Starting with Tor version 0.2.7.1 it is possible, through Tor's control socket
API, to create and destroy 'ephemeral' hidden services programmatically.
https://stem.torproject.org/api/control.html#stem.control.Controller.create_ephemeral_hidden_service

This means that if Tor is running (and proper authorization is available),
bitcoin automatically creates a hidden service to listen on, without user
manual configuration. This will positively affect the number of available
.onion nodes.

- When the node is started, connect to Tor through control socket
- Send `ADD_ONION` command
- First time:
    - Make it create a hidden service key
    - Save the key in the data directory for later usage
- Make it redirect port 8333 to the local port 8333 (or whatever port we're listening on).
- Keep control socket connection open for as long node is running. The hidden service will
  (by default) automatically go away when the connection is closed.

1 files changed, 1 insertions, 4 deletions

diff --git a/src/netbase.cpp b/src/netbase.cpp
index f5316965ce..83cedfb620 100644
--- a/src/netbase.cpp
+++ b/src/netbase.cpp
@@ -227,10 +227,7 @@ bool LookupNumeric(const char *pszName, CService& addr, int portDefault)
     return Lookup(pszName, addr, portDefault, false);
 }
 
-/**
- * Convert milliseconds to a struct timeval for select.
- */
-struct timeval static MillisToTimeval(int64_t nTimeout)
+struct timeval MillisToTimeval(int64_t nTimeout)
 {
     struct timeval timeout;
     timeout.tv_sec  = nTimeout / 1000;