[dpdk-dev] [PATCH v5] Add toeplitz hash algorithm used by RSS

[Vladimir Medvedkin <medvedkinv@gmail.com>]

Software implementation of the Toeplitz hash function used by RSS.
Can be used either for packet distribution on single queue NIC
or for simulating of RSS computation on specific NIC (for example
after GRE header decapsulating).

v5 changes
- Fix errors reported by checkpatch.pl

v4 changes
- Fix copyright
- rename bswap_mask constant, add rte_ prefix
- change rte_ipv[46]_tuple struct
- change rte_thash_load_v6_addr prototype

v3 changes
- Rework API to be more generic
- Add sctp_tag into tuple

v2 changes
- Add ipv6 support
- Various style fixes

Signed-off-by: Vladimir Medvedkin <medvedkinv@gmail.com>
---
 lib/librte_hash/Makefile    |   1 +
 lib/librte_hash/rte_thash.h | 207 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 208 insertions(+)
 create mode 100644 lib/librte_hash/rte_thash.h

diff --git a/lib/librte_hash/Makefile b/lib/librte_hash/Makefile
index 3696cb1..981230b 100644
--- a/lib/librte_hash/Makefile
+++ b/lib/librte_hash/Makefile
@@ -49,6 +49,7 @@ SRCS-$(CONFIG_RTE_LIBRTE_HASH) += rte_fbk_hash.c
 SYMLINK-$(CONFIG_RTE_LIBRTE_HASH)-include := rte_hash.h
 SYMLINK-$(CONFIG_RTE_LIBRTE_HASH)-include += rte_hash_crc.h
 SYMLINK-$(CONFIG_RTE_LIBRTE_HASH)-include += rte_jhash.h
+SYMLINK-$(CONFIG_RTE_LIBRTE_HASH)-include += rte_thash.h
 SYMLINK-$(CONFIG_RTE_LIBRTE_HASH)-include += rte_fbk_hash.h
 
 # this lib needs eal
diff --git a/lib/librte_hash/rte_thash.h b/lib/librte_hash/rte_thash.h
new file mode 100644
index 0000000..877bd50
--- /dev/null
+++ b/lib/librte_hash/rte_thash.h
@@ -0,0 +1,207 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2015 Vladimir Medvedkin <medvedkinv@gmail.com>
+ *   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.
+ */
+
+#ifndef _RTE_THASH_H
+#define _RTE_THASH_H
+
+/**
+ * @file
+ *
+ * toeplitz hash functions.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Software implementation of the Toeplitz hash function used by RSS.
+ * Can be used either for packet distribution on single queue NIC
+ * or for simulating of RSS computation on specific NIC (for example
+ * after GRE header decapsulating)
+ */
+
+#include <stdint.h>
+#include <rte_byteorder.h>
+#include <rte_vect.h>
+#include <rte_ip.h>
+
+/* Byte swap mask used for converting IPv6 address
+ * 4-byte chunks to CPU byte order
+ */
+static const __m128i rte_thash_ipv6_bswap_mask = {
+		0x0405060700010203, 0x0C0D0E0F08090A0B};
+
+#define RTE_THASH_V4_L3	 2	/*calculate hash of ipv4 header only*/
+#define RTE_THASH_V4_L4	 3	/*calculate hash of ipv4 + transport headers*/
+#define RTE_THASH_V6_L3	 8	/*calculate hash of ipv6 header only */
+#define RTE_THASH_V6_L4	 9	/*calculate hash of ipv6 + transport headers */
+
+/**
+ * IPv4 tuple
+ * addreses and ports/sctp_tag have to be CPU byte order
+ */
+struct rte_ipv4_tuple {
+	uint32_t	src_addr;
+	uint32_t	dst_addr;
+	union {
+		struct {
+			uint16_t dport;
+			uint16_t sport;
+		};
+		uint32_t        sctp_tag;
+	};
+};
+
+/**
+ * IPv6 tuple
+ * Addresses have to be filled by rte_thash_load_v6_addr()
+ * ports/sctp_tag have to be CPU byte order
+ */
+struct rte_ipv6_tuple {
+	uint8_t		src_addr[16];
+	uint8_t		dst_addr[16];
+	union {
+		struct {
+			uint16_t dport;
+			uint16_t sport;
+		};
+		uint32_t        sctp_tag;
+	};
+};
+
+union rte_thash_tuple {
+	struct rte_ipv4_tuple	v4;
+	struct rte_ipv6_tuple	v6;
+} __aligned(size);
+
+/**
+ * Prepare special converted key to use with rte_softrss_be()
+ * @param orig
+ *   pointer to original RSS key
+ * @param targ
+ *   pointer to target RSS key
+ * @param len
+ *   RSS key length
+ */
+static inline void
+rte_convert_rss_key(const uint32_t *orig, uint32_t *targ, int len)
+{
+	int i;
+
+	for (i = 0; i < (len >> 2); i++)
+		targ[i] = rte_be_to_cpu_32(orig[i]);
+}
+
+/**
+ * Prepare and load IPv6 address
+ * @param orig
+ *   Pointer to ipv6 header of the original packet
+ * @param targ
+ *   Pointer to rte_ipv6_tuple structure
+ */
+static inline void
+rte_thash_load_v6_addr(const struct ipv6_hdr *orig, union rte_thash_tuple *targ)
+{
+	__m128i ipv6 = _mm_loadu_si128((const __m128i *)orig->src_addr);
+	*(__m128i *)targ->v6.src_addr =
+			_mm_shuffle_epi8(ipv6, rte_thash_ipv6_bswap_mask);
+	ipv6 = _mm_loadu_si128((const __m128i *)orig->dst_addr);
+	*(__m128i *)targ->v6.dst_addr =
+			_mm_shuffle_epi8(ipv6, rte_thash_ipv6_bswap_mask);
+}
+
+/**
+ * Generic implementation. Can be used with original rss_key
+ * @param input_tuple
+ *   Pointer to input tuple
+ * @param input_len
+ *   Length of input_tuple in 4-bytes chunks
+ * @param rss_key
+ *   Pointer to RSS hash key.
+ * @return
+ *   Calculated hash value.
+ */
+static inline uint32_t
+rte_softrss(uint32_t *input_tuple, uint32_t input_len,
+		const uint8_t *rss_key)
+{
+	uint32_t i, j, ret = 0;
+
+	for (j = 0; j < input_len; j++) {
+		for (i = 0; i < 32; i++) {
+			if (input_tuple[j] & (1 << (31 - i))) {
+				ret ^= rte_cpu_to_be_32(((const uint32_t *)rss_key)[j]) << i |
+					(uint32_t)((uint64_t)(rte_cpu_to_be_32(((const uint32_t *)rss_key)[j + 1])) >>
+					(32 - i));
+			}
+		}
+	}
+	return ret;
+}
+
+/**
+ * Optimized implementation.
+ * If you want the calculated hash value matches NIC RSS value
+ * you have to use special converted key with rte_convert_rss_key() fn.
+ * @param input_tuple
+ *   Pointer to input tuple
+ * @param input_len
+ *   Length of input_tuple in 4-bytes chunks
+ * @param *rss_key
+ *   Pointer to RSS hash key.
+ * @return
+ *   Calculated hash value.
+ */
+static inline uint32_t
+rte_softrss_be(uint32_t *input_tuple, uint32_t input_len,
+		const uint8_t *rss_key)
+{
+	uint32_t i, j, ret = 0;
+
+	for (j = 0; j < input_len; j++) {
+		for (i = 0; i < 32; i++) {
+			if (input_tuple[j] & (1 << (31 - i))) {
+				ret ^= ((const uint32_t *)rss_key)[j] << i |
+					(uint32_t)((uint64_t)(((const uint32_t *)rss_key)[j + 1]) >> (32 - i));
+			}
+		}
+	}
+	return ret;
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_THASH_H */
-- 
1.8.3.2