sendme: Move note_cell_digest() to relay_crypto module

Because this function is poking within the relay_crypto_t object, move the
function to the module so we can keep it opaque as much as possible.

Part of #26288

Signed-off-by: David Goulet <dgoulet@torproject.org>

2 files changed, 11 insertions, 0 deletions

diff --git a/src/core/crypto/relay_crypto.c b/src/core/crypto/relay_crypto.c
index eddc4298e2..3a6dad4b1d 100644
--- a/src/core/crypto/relay_crypto.c
+++ b/src/core/crypto/relay_crypto.c
@@ -91,6 +91,15 @@ relay_crypt_one_payload(crypto_cipher_t *cipher, uint8_t *in)
   crypto_cipher_crypt_inplace(cipher, (char*) in, CELL_PAYLOAD_SIZE);
 }
 
+/** Record the b_digest from <b>crypto</b> and put it in the sendme_digest. */
+void
+relay_crypto_record_sendme_digest(relay_crypto_t *crypto)
+{
+  tor_assert(crypto);
+  crypto_digest_get_digest(crypto->b_digest, (char *) crypto->sendme_digest,
+                           sizeof(crypto->sendme_digest));
+}
+
 /** Do the appropriate en/decryptions for <b>cell</b> arriving on
  * <b>circ</b> in direction <b>cell_direction</b>.
  *
diff --git a/src/core/crypto/relay_crypto.h b/src/core/crypto/relay_crypto.h
index 45a21d14ab..1009f1841b 100644
--- a/src/core/crypto/relay_crypto.h
+++ b/src/core/crypto/relay_crypto.h
@@ -27,5 +27,7 @@ void relay_crypto_clear(relay_crypto_t *crypto);
 
 void relay_crypto_assert_ok(const relay_crypto_t *crypto);
 
+void relay_crypto_record_sendme_digest(relay_crypto_t *crypto);
+
 #endif /* !defined(TOR_RELAY_CRYPTO_H) */