--- /dev/null
+/*
+ *------------------------------------------------------------------
+ * Copyright (c) 2019 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *------------------------------------------------------------------
+ */
+
+/*
+ *------------------------------------------------------------------
+ * Copyright(c) 2018, Intel Corporation All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in
+ * the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Intel Corporation nor the names of its
+ * contributors may be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES * LOSS OF USE,
+ * DATA, OR PROFITS * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *------------------------------------------------------------------
+ */
+
+/*
+ * Based on work by: Shay Gueron, Michael E. Kounavis, Erdinc Ozturk,
+ * Vinodh Gopal, James Guilford, Tomasz Kantecki
+ *
+ * References:
+ * [1] Vinodh Gopal et. al. Optimized Galois-Counter-Mode Implementation on
+ * Intel Architecture Processors. August, 2010
+ * [2] Erdinc Ozturk et. al. Enabling High-Performance Galois-Counter-Mode on
+ * Intel Architecture Processors. October, 2012.
+ * [3] intel-ipsec-mb library, https://github.com/01org/intel-ipsec-mb.git
+ *
+ * Definitions:
+ * GF Galois Extension Field GF(2^128) - finite field where elements are
+ * represented as polynomials with coefficients in GF(2) with the
+ * highest degree of 127. Polynomials are represented as 128-bit binary
+ * numbers where each bit represents one coefficient.
+ * e.g. polynomial x^5 + x^3 + x + 1 is represented in binary 101011.
+ * H hash key (128 bit)
+ * POLY irreducible polynomial x^127 + x^7 + x^2 + x + 1
+ * RPOLY irreducible polynomial x^128 + x^127 + x^126 + x^121 + 1
+ * + addition in GF, which equals to XOR operation
+ * * multiplication in GF
+ *
+ * GF multiplication consists of 2 steps:
+ * - carry-less multiplication of two 128-bit operands into 256-bit result
+ * - reduction of 256-bit result into 128-bit with modulo POLY
+ *
+ * GHash is calculated on 128-bit blocks of data according to the following
+ * formula:
+ * GH = (GH + data) * hash_key
+ *
+ * To avoid bit-reflection of data, this code uses GF multipication
+ * with reversed polynomial:
+ * a * b * x^-127 mod RPOLY
+ *
+ * To improve computation speed table Hi is precomputed with powers of H',
+ * where H' is calculated as H<<1 mod RPOLY.
+ * This allows us to improve performance by deferring reduction. For example
+ * to caclulate ghash of 4 128-bit blocks of data (b0, b1, b2, b3), we can do:
+ *
+ * __i128 Hi[4];
+ * ghash_precompute (H, Hi, 4);
+ *
+ * ghash_data_t _gd, *gd = &_gd;
+ * ghash_mul_first (gd, GH ^ b0, Hi[3]);
+ * ghash_mul_next (gd, b1, Hi[2]);
+ * ghash_mul_next (gd, b2, Hi[1]);
+ * ghash_mul_next (gd, b3, Hi[0]);
+ * ghash_reduce (gd);
+ * ghash_reduce2 (gd);
+ * GH = ghash_final (gd);
+ *
+ * Reduction step is split into 3 functions so it can be better interleaved
+ * with other code, (i.e. with AES computation).
+ */
+
+#ifndef __ghash_h__
+#define __ghash_h__
+
+/* on AVX-512 systems we can save a clock cycle by using ternary logic
+ instruction to calculate a XOR b XOR c */
+static_always_inline __m128i
+ghash_xor3 (__m128i a, __m128i b, __m128i c)
+{
+#if defined (__AVX512F__)
+ return _mm_ternarylogic_epi32 (a, b, c, 0x96);
+#endif
+ return a ^ b ^ c;
+}
+
+typedef struct
+{
+ __m128i mid, hi, lo, tmp_lo, tmp_hi;
+ int pending;
+} ghash_data_t;
+
+static const __m128i ghash_poly = { 1, 0xC200000000000000 };
+static const __m128i ghash_poly2 = { 0x1C2000000, 0xC200000000000000 };
+
+static_always_inline void
+ghash_mul_first (ghash_data_t * gd, __m128i a, __m128i b)
+{
+ /* a1 * b1 */
+ gd->hi = _mm_clmulepi64_si128 (a, b, 0x11);
+ /* a0 * b0 */
+ gd->lo = _mm_clmulepi64_si128 (a, b, 0x00);
+ /* a0 * b1 ^ a1 * b0 */
+ gd->mid = (_mm_clmulepi64_si128 (a, b, 0x01) ^
+ _mm_clmulepi64_si128 (a, b, 0x10));
+
+ /* set gd->pending to 0 so next invocation of ghash_mul_next(...) knows that
+ there is no pending data in tmp_lo and tmp_hi */
+ gd->pending = 0;
+}
+
+static_always_inline void
+ghash_mul_next (ghash_data_t * gd, __m128i a, __m128i b)
+{
+ /* a1 * b1 */
+ __m128i hi = _mm_clmulepi64_si128 (a, b, 0x11);
+ /* a0 * b0 */
+ __m128i lo = _mm_clmulepi64_si128 (a, b, 0x00);
+
+ /* this branch will be optimized out by the compiler, and it allows us to
+ reduce number of XOR operations by using ternary logic */
+ if (gd->pending)
+ {
+ /* there is peding data from previous invocation so we can XOR */
+ gd->hi = ghash_xor3 (gd->hi, gd->tmp_hi, hi);
+ gd->lo = ghash_xor3 (gd->lo, gd->tmp_lo, lo);
+ gd->pending = 0;
+ }
+ else
+ {
+ /* there is no peding data from previous invocation so we postpone XOR */
+ gd->tmp_hi = hi;
+ gd->tmp_lo = lo;
+ gd->pending = 1;
+ }
+
+ /* gd->mid ^= a0 * b1 ^ a1 * b0 */
+ gd->mid = ghash_xor3 (gd->mid,
+ _mm_clmulepi64_si128 (a, b, 0x01),
+ _mm_clmulepi64_si128 (a, b, 0x10));
+}
+
+static_always_inline void
+ghash_reduce (ghash_data_t * gd)
+{
+ __m128i r;
+
+ /* Final combination:
+ gd->lo ^= gd->mid << 64
+ gd->hi ^= gd->mid >> 64 */
+ __m128i midl = _mm_slli_si128 (gd->mid, 8);
+ __m128i midr = _mm_srli_si128 (gd->mid, 8);
+
+ if (gd->pending)
+ {
+ gd->lo = ghash_xor3 (gd->lo, gd->tmp_lo, midl);
+ gd->hi = ghash_xor3 (gd->hi, gd->tmp_hi, midr);
+ }
+ else
+ {
+ gd->lo ^= midl;
+ gd->hi ^= midr;
+ }
+
+ r = _mm_clmulepi64_si128 (ghash_poly2, gd->lo, 0x01);
+ gd->lo ^= _mm_slli_si128 (r, 8);
+}
+
+static_always_inline void
+ghash_reduce2 (ghash_data_t * gd)
+{
+ gd->tmp_lo = _mm_clmulepi64_si128 (ghash_poly2, gd->lo, 0x00);
+ gd->tmp_hi = _mm_clmulepi64_si128 (ghash_poly2, gd->lo, 0x10);
+}
+
+static_always_inline __m128i
+ghash_final (ghash_data_t * gd)
+{
+ return ghash_xor3 (gd->hi, _mm_srli_si128 (gd->tmp_lo, 4),
+ _mm_slli_si128 (gd->tmp_hi, 4));
+}
+
+static_always_inline __m128i
+ghash_mul (__m128i a, __m128i b)
+{
+ ghash_data_t _gd, *gd = &_gd;
+ ghash_mul_first (gd, a, b);
+ ghash_reduce (gd);
+ ghash_reduce2 (gd);
+ return ghash_final (gd);
+}
+
+static_always_inline void
+ghash_precompute (__m128i H, __m128i * Hi, int count)
+{
+ __m128i r;
+ /* calcullate H<<1 mod poly from the hash key */
+ r = _mm_srli_epi64 (H, 63);
+ H = _mm_slli_epi64 (H, 1);
+ H |= _mm_slli_si128 (r, 8);
+ r = _mm_srli_si128 (r, 8);
+ r = _mm_shuffle_epi32 (r, 0x24);
+ /* *INDENT-OFF* */
+ r = _mm_cmpeq_epi32 (r, (__m128i) (u32x4) {1, 0, 0, 1});
+ /* *INDENT-ON* */
+ Hi[0] = H ^ (r & ghash_poly);
+
+ /* calculate H^(i + 1) */
+ for (int i = 1; i < count; i++)
+ Hi[i] = ghash_mul (Hi[0], Hi[i - 1]);
+}
+
+#endif /* __ghash_h__ */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
Code Review / vpp.git / blobdiff