Add some more OpenSSL 1.1.0 compat functions

Summary: Adds functions for DH length to the compat library.

Reviewed By: yfeldblum

Differential Revision: D13584117

fbshipit-source-id: ef753d58ee400fbaf8d47f59b7d39e17380ed417

folly/portability/OpenSSL.cpp

@@ -272,6 +272,19 @@ void DH_get0_key(
   }
 }
 
+long DH_get_length(const DH* dh) {
+  return dh->length;
+}
+
+int DH_set_length(DH* dh, long length) {
+  if (dh != nullptr) {
+    dh->length = length;
+    return 1;
+  } else {
+    return 0;
+  }
+}
+
 void DSA_get0_pqg(
     const DSA* dsa,
     const BIGNUM** p,

folly/portability/OpenSSL.h

@@ -160,6 +160,8 @@ void DH_get0_pqg(
     const BIGNUM** q,
     const BIGNUM** g);
 void DH_get0_key(const DH* dh, const BIGNUM** pub_key, const BIGNUM** priv_key);
+long DH_get_length(const DH* dh);
+int DH_set_length(DH* dh, long length);
 
 void DSA_get0_pqg(
     const DSA* dsa,