Expose crypto_digest_algorithm_get_length from crypto.c

Also, use it in routerparse.c

src/common/crypto.c

@@ -1727,7 +1727,7 @@ crypto_digest_algorithm_parse_name(const char *name)
 }
 
 /** Given an algorithm, return the digest length in bytes. */
-static inline size_t
+size_t
 crypto_digest_algorithm_get_length(digest_algorithm_t alg)
 {
   switch (alg) {

src/common/crypto.h

@@ -233,6 +233,7 @@ void crypto_digest_smartlist(char *digest_out, size_t len_out,
                              const struct smartlist_t *lst, const char *append,
                              digest_algorithm_t alg);
 const char *crypto_digest_algorithm_get_name(digest_algorithm_t alg);
+size_t crypto_digest_algorithm_get_length(digest_algorithm_t alg);
 int crypto_digest_algorithm_parse_name(const char *name);
 crypto_digest_t *crypto_digest_new(void);
 crypto_digest_t *crypto_digest256_new(digest_algorithm_t algorithm);

src/or/routerparse.c

@@ -3531,10 +3531,8 @@ networkstatus_parse_detached_signatures(const char *s, const char *eos)
       continue;
     }
 
-    expected_length =
-      (alg == DIGEST_SHA1) ? HEX_DIGEST_LEN : HEX_DIGEST256_LEN;
-    digest_length =
-      (alg == DIGEST_SHA1) ? DIGEST_LEN : DIGEST256_LEN;
+    digest_length = crypto_digest_algorithm_get_length(alg);
+    expected_length = digest_length * 2; /* hex encoding */
 
     if (strlen(hexdigest) != expected_length) {
       log_warn(LD_DIR, "Wrong length on consensus-digest in detached "