test: Crypto groundwork for e2e circuit unittests.

- Move some crypto structures so that they are visible by tests.

- Introduce a func to count number of hops in cpath which will be used
  by the tests.

- Mark a function as mockable.

src/common/crypto.c

@@ -1839,21 +1839,6 @@ crypto_digest_algorithm_get_length(digest_algorithm_t alg)
   }
 }
 
-/** Intermediate information about the digest of a stream of data. */
-struct crypto_digest_t {
-  digest_algorithm_t algorithm; /**< Which algorithm is in use? */
-   /** State for the digest we're using.  Only one member of the
-    * union is usable, depending on the value of <b>algorithm</b>. Note also
-    * that space for other members might not even be allocated!
-    */
-  union {
-    SHA_CTX sha1; /**< state for SHA1 */
-    SHA256_CTX sha2; /**< state for SHA256 */
-    SHA512_CTX sha512; /**< state for SHA512 */
-    keccak_state sha3; /**< state for SHA3-[256,512] */
-  } d;
-};
-
 /**
  * Return the number of bytes we need to malloc in order to get a
  * crypto_digest_t for <b>alg</b>, or the number of bytes we need to wipe

src/common/crypto.h

@@ -20,6 +20,9 @@
 #include "testsupport.h"
 #include "compat.h"
 
+#include <openssl/engine.h>
+#include "keccak-tiny/keccak-tiny.h"
+
 /*
   Macro to create an arbitrary OpenSSL version number as used by
   OPENSSL_VERSION_NUMBER or SSLeay(), since the actual numbers are a bit hard
@@ -335,6 +338,22 @@ struct dh_st *crypto_dh_get_dh_(crypto_dh_t *dh);
 void crypto_add_spaces_to_fp(char *out, size_t outlen, const char *in);
 
 #ifdef CRYPTO_PRIVATE
+
+/** Intermediate information about the digest of a stream of data. */
+struct crypto_digest_t {
+  digest_algorithm_t algorithm; /**< Which algorithm is in use? */
+   /** State for the digest we're using.  Only one member of the
+    * union is usable, depending on the value of <b>algorithm</b>. Note also
+    * that space for other members might not even be allocated!
+    */
+  union {
+    SHA_CTX sha1; /**< state for SHA1 */
+    SHA256_CTX sha2; /**< state for SHA256 */
+    SHA512_CTX sha512; /**< state for SHA512 */
+    keccak_state sha3; /**< state for SHA3-[256,512] */
+  } d;
+};
+
 STATIC int crypto_force_rand_ssleay(void);
 STATIC int crypto_strongest_rand_raw(uint8_t *out, size_t out_len);
 

src/or/circuitbuild.c

@@ -2338,6 +2338,30 @@ onion_append_to_cpath(crypt_path_t **head_ptr, crypt_path_t *new_hop)
   }
 }
 
+#ifdef TOR_UNIT_TESTS
+
+/** Unittest helper function: Count number of hops in cpath linked list. */
+unsigned int
+cpath_get_n_hops(crypt_path_t **head_ptr)
+{
+  unsigned int n_hops = 0;
+  crypt_path_t *tmp;
+
+  if (!*head_ptr) {
+    return 0;
+  }
+
+  tmp = *head_ptr;
+  if (tmp) {
+    n_hops++;
+    tmp = (*head_ptr)->next;
+  }
+
+  return n_hops;
+}
+
+#endif
+
 /** A helper function used by onion_extend_cpath(). Use <b>purpose</b>
  * and <b>state</b> and the cpath <b>head</b> (currently populated only
  * to length <b>cur_len</b> to decide a suitable middle hop for a

src/or/circuitbuild.h

@@ -83,6 +83,8 @@ MOCK_DECL(STATIC int, count_acceptable_nodes, (smartlist_t *nodes));
 #if defined(ENABLE_TOR2WEB_MODE) || defined(TOR_UNIT_TESTS)
 STATIC const node_t *pick_tor2web_rendezvous_node(router_crn_flags_t flags,
                                                   const or_options_t *options);
+unsigned int cpath_get_n_hops(crypt_path_t **head_ptr);
+
 #endif
 
 #endif

src/or/connection_edge.c

@@ -2455,8 +2455,8 @@ connection_ap_get_begincell_flags(entry_connection_t *ap_conn)
  *
  * If ap_conn is broken, mark it for close and return -1. Else return 0.
  */
-int
-connection_ap_handshake_send_begin(entry_connection_t *ap_conn)
+MOCK_IMPL(int,
+connection_ap_handshake_send_begin,(entry_connection_t *ap_conn))
 {
   char payload[CELL_PAYLOAD_SIZE];
   int payload_len;

src/or/connection_edge.h

@@ -33,7 +33,8 @@ int connection_edge_finished_connecting(edge_connection_t *conn);
 void connection_ap_about_to_close(entry_connection_t *edge_conn);
 void connection_exit_about_to_close(edge_connection_t *edge_conn);
 
-int connection_ap_handshake_send_begin(entry_connection_t *ap_conn);
+MOCK_DECL(int,
+          connection_ap_handshake_send_begin,(entry_connection_t *ap_conn));
 int connection_ap_handshake_send_resolve(entry_connection_t *ap_conn);
 
 entry_connection_t  *connection_ap_make_link(connection_t *partner,