编写连接业务层的代码。

platform/src/ssl_utils.cpp

@@ -4,6 +4,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <limits.h>
+#include <assert.h>
 
 #include <openssl/crypto.h>
 #include <openssl/engine.h>
@@ -150,6 +151,45 @@ void ssl_openssl_version(void)
 #endif /* !SSL_OP_TLS_ROLLBACK_BUG */
 	fprintf(stderr, "\n");
 }
+int sslver_str2num(const char * version_str)
+{
+	int sslversion = -1;
+
+	assert(OPENSSL_VERSION_NUMBER >= 0x10100000L);
+
+	/*
+	 * Support for SSLv2 and the corresponding SSLv2_method(),
+	 * SSLv2_server_method() and SSLv2_client_method() functions were
+	 * removed in OpenSSL 1.1.0.
+	 */
+	if (!strcmp(version_str, "ssl3"))
+	{
+		sslversion = SSL3_VERSION;
+	}
+	else if (!strcmp(version_str, "tls10") || !strcmp(version_str, "tls1"))
+	{
+		sslversion = TLS1_VERSION;
+	}
+	else if (!strcmp(version_str, "tls11"))
+	{
+		sslversion = TLS1_1_VERSION;
+	}
+	else if (!strcmp(version_str, "tls12"))
+	{
+		sslversion = TLS1_2_VERSION;
+	}
+	else if (!strcmp(version_str, "tls13"))
+	{
+		sslversion = TLS1_3_VERSION;
+	}
+
+	else
+	{
+		sslversion = -1;
+	}
+
+	return sslversion;
+}
 
 /*
  * 1 if OpenSSL has been initialized, 0 if not.  When calling a _load()