Record the states of failing OR connections

This code lets us record the state of any outgoing OR connection
that fails before it becomes open, so we can notice if they're all
dying in the same SSL state or the same OR handshake state.

More work is still needed:
  - We need documentation
  - We need to actually call the code that reports the failure when
    we realize that we're having a hard time connecting out or
    making circuits.
  - We need to periodically clear out all this data -- perhaps,
    whenever we build a circuit successfully?
  - We'll eventually want to expose it to controllers, perhaps.

Partial implementation of feature 3116.

2 files changed, 32 insertions, 0 deletions

diff --git a/src/common/tortls.c b/src/common/tortls.c
index 94ca81ba49..8db47a6f21 100644
--- a/src/common/tortls.c
+++ b/src/common/tortls.c
@@ -222,6 +222,37 @@ ssl_state_to_string(int ssl_state)
   return buf;
 }
 
+/** DOCDOC 3116 */
+void
+tor_tls_get_state_description(tor_tls_t *tls, char *buf, size_t sz)
+{
+  const char *ssl_state;
+  const char *tortls_state;
+
+  if (PREDICT_UNLIKELY(!tls || !tls->ssl)) {
+    strlcpy(buf, "(No SSL object)", sz);
+    return;
+  }
+
+  ssl_state = ssl_state_to_string(tls->ssl->state);
+  switch (tls->state) {
+#define CASE(st) case TOR_TLS_ST_##st: tortls_state = #st ; break
+    CASE(HANDSHAKE);
+    CASE(OPEN);
+    CASE(GOTCLOSE);
+    CASE(SENTCLOSE);
+    CASE(CLOSED);
+    CASE(RENEGOTIATE);
+    CASE(BUFFEREVENT);
+#undef CASE
+  default:
+    tortls_state = "unknown";
+    break;
+  }
+
+  tor_snprintf(buf, sz, "%s in %s", ssl_state, tortls_state);
+}
+
 void
 tor_tls_log_one_error(tor_tls_t *tls, unsigned long err,
                   int severity, int domain, const char *doing)
diff --git a/src/common/tortls.h b/src/common/tortls.h
index ecb5bd2fbe..9b8108b42b 100644
--- a/src/common/tortls.h
+++ b/src/common/tortls.h
@@ -48,6 +48,7 @@ typedef struct tor_tls_t tor_tls_t;
 
 #define TOR_TLS_IS_ERROR(rv) ((rv) < TOR_TLS_CLOSE)
 const char *tor_tls_err_to_string(int err);
+void tor_tls_get_state_description(tor_tls_t *tls, char *buf, size_t sz);
 
 void tor_tls_free_all(void);
 int tor_tls_context_init(int is_public_server,