crypto: add HMAC algorithms framework

This patch introduce HMAC algorithms framework.

Signed-off-by: Longpeng(Mike) <longpeng2@huawei.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

crypto/hmac.c

@@ -0,0 +1,72 @@
+/*
+ * QEMU Crypto hmac algorithms
+ *
+ * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * (at your option) any later version.  See the COPYING file in the
+ * top-level directory.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "crypto/hmac.h"
+
+static const char hex[] = "0123456789abcdef";
+
+int qcrypto_hmac_bytes(QCryptoHmac *hmac,
+                       const char *buf,
+                       size_t len,
+                       uint8_t **result,
+                       size_t *resultlen,
+                       Error **errp)
+{
+    struct iovec iov = {
+            .iov_base = (char *)buf,
+            .iov_len = len
+    };
+
+    return qcrypto_hmac_bytesv(hmac, &iov, 1, result, resultlen, errp);
+}
+
+int qcrypto_hmac_digestv(QCryptoHmac *hmac,
+                         const struct iovec *iov,
+                         size_t niov,
+                         char **digest,
+                         Error **errp)
+{
+    uint8_t *result = NULL;
+    size_t resultlen = 0;
+    size_t i;
+
+    if (qcrypto_hmac_bytesv(hmac, iov, niov, &result, &resultlen, errp) < 0) {
+        return -1;
+    }
+
+    *digest = g_new0(char, (resultlen * 2) + 1);
+
+    for (i = 0 ; i < resultlen ; i++) {
+        (*digest)[(i * 2)] = hex[(result[i] >> 4) & 0xf];
+        (*digest)[(i * 2) + 1] = hex[result[i] & 0xf];
+    }
+
+    (*digest)[resultlen * 2] = '\0';
+
+    g_free(result);
+    return 0;
+}
+
+int qcrypto_hmac_digest(QCryptoHmac *hmac,
+                        const char *buf,
+                        size_t len,
+                        char **digest,
+                        Error **errp)
+{
+    struct iovec iov = {
+            .iov_base = (char *)buf,
+            .iov_len = len
+    };
+
+    return qcrypto_hmac_digestv(hmac, &iov, 1, digest, errp);
+}