[PATCH v9 6/7] crypto: add curve25519 params and expose them

[Meng Yu]

1. Add curve 25519 parameters in 'crypto/ecc_curve_defs.h';
2. Add curve25519 interface 'ecc_get_curve25519_param' in
   'include/crypto/ecc_curve.h', to make its parameters be
   exposed to everyone in kernel tree.

Signed-off-by: Meng Yu <yumeng18@xxxxxxxxxx>
Reviewed-by: Zaibo Xu <xuzaibo@xxxxxxxxxx>
---
 crypto/ecc.c               |  6 ++++++
 crypto/ecc_curve_defs.h    | 17 +++++++++++++++++
 include/crypto/ecc_curve.h |  7 +++++++
 3 files changed, 30 insertions(+)

diff --git a/crypto/ecc.c b/crypto/ecc.c
index 4b55ad0..0798a18 100644
--- a/crypto/ecc.c
+++ b/crypto/ecc.c
@@ -43,6 +43,12 @@ typedef struct {
 	u64 m_high;
 } uint128_t;
 
+/* Returns curv25519 curve param */
+const struct ecc_curve *ecc_get_curve25519(void)
+{
+	return &ecc_25519;
+}
+EXPORT_SYMBOL(ecc_get_curve25519);
 
 const struct ecc_curve *ecc_get_curve(unsigned int curve_id)
 {
diff --git a/crypto/ecc_curve_defs.h b/crypto/ecc_curve_defs.h
index 69be6c7..d7769cc 100644
--- a/crypto/ecc_curve_defs.h
+++ b/crypto/ecc_curve_defs.h
@@ -54,4 +54,21 @@ static struct ecc_curve nist_p256 = {
 	.b = nist_p256_b
 };
 
+/* curve25519 */
+static u64 curve25519_g_x[] = { 0x0000000000000009, 0x0000000000000000,
+				0x0000000000000000, 0x0000000000000000 };
+static u64 curve25519_p[] = { 0xffffffffffffffed, 0xffffffffffffffff,
+				0xffffffffffffffff, 0x7fffffffffffffff };
+static u64 curve25519_a[] = { 0x000000000001DB41, 0x0000000000000000,
+				0x0000000000000000, 0x0000000000000000 };
+static const struct ecc_curve ecc_25519 = {
+	.name = "curve25519",
+	.g = {
+		.x = curve25519_g_x,
+		.ndigits = 4,
+	},
+	.p = curve25519_p,
+	.a = curve25519_a,
+};
+
 #endif
diff --git a/include/crypto/ecc_curve.h b/include/crypto/ecc_curve.h
index 19a35da..7096478 100644
--- a/include/crypto/ecc_curve.h
+++ b/include/crypto/ecc_curve.h
@@ -50,4 +50,11 @@ struct ecc_curve {
  */
 const struct ecc_curve *ecc_get_curve(unsigned int curve_id);
 
+/**
+ * ecc_get_curve25519() - get curve25519 curve;
+ *
+ * Returns curve25519
+ */
+const struct ecc_curve *ecc_get_curve25519(void);
+
 #endif
-- 
2.8.1