[dpdk-dev] [PATCH v2 14/28] common/cnxk: support anti-replay check in SW for cn9k

[Nithin Dabilpuram <ndabilpuram@marvell.com>]

From: Srujana Challa <schalla@marvell.com>

Adds anti replay SW implementation for cn9k platform.

Signed-off-by: Srujana Challa <schalla@marvell.com>
---
 drivers/common/cnxk/cnxk_security_ar.h | 184 +++++++++++++++++++++++++++++++++
 1 file changed, 184 insertions(+)
 create mode 100644 drivers/common/cnxk/cnxk_security_ar.h

diff --git a/drivers/common/cnxk/cnxk_security_ar.h b/drivers/common/cnxk/cnxk_security_ar.h
new file mode 100644
index 0000000..6bc517c
--- /dev/null
+++ b/drivers/common/cnxk/cnxk_security_ar.h
@@ -0,0 +1,184 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(C) 2021 Marvell.
+ */
+
+#ifndef __CNXK_SECURITY_AR_H__
+#define __CNXK_SECURITY_AR_H__
+
+#include <rte_mbuf.h>
+
+#include "cnxk_security.h"
+
+#define CNXK_ON_AR_WIN_SIZE_MAX 1024
+
+/* u64 array size to fit anti replay window bits */
+#define AR_WIN_ARR_SZ                                                          \
+	(PLT_ALIGN_CEIL(CNXK_ON_AR_WIN_SIZE_MAX, BITS_PER_LONG_LONG) /        \
+	 BITS_PER_LONG_LONG)
+
+#define WORD_SHIFT 6
+#define WORD_SIZE  (1 << WORD_SHIFT)
+#define WORD_MASK  (WORD_SIZE - 1)
+
+#define IPSEC_ANTI_REPLAY_FAILED (-1)
+
+struct cnxk_on_ipsec_ar {
+	rte_spinlock_t lock;
+	uint32_t winb;
+	uint32_t wint;
+	uint64_t base;			/**< base of the anti-replay window */
+	uint64_t window[AR_WIN_ARR_SZ]; /**< anti-replay window */
+};
+
+static inline int
+cnxk_on_anti_replay_check(uint64_t seq, struct cnxk_on_ipsec_ar *ar,
+			  uint32_t winsz)
+{
+	uint64_t ex_winsz = winsz + WORD_SIZE;
+	uint64_t *window = &ar->window[0];
+	uint64_t seqword, shiftwords;
+	uint64_t base = ar->base;
+	uint32_t winb = ar->winb;
+	uint32_t wint = ar->wint;
+	uint64_t winwords;
+	uint64_t bit_pos;
+	uint64_t shift;
+	uint64_t *wptr;
+	uint64_t tmp;
+
+	winwords = ex_winsz >> WORD_SHIFT;
+	if (winsz > 64)
+		goto slow_shift;
+	/* Check if the seq is the biggest one yet */
+	if (likely(seq > base)) {
+		shift = seq - base;
+		if (shift < winsz) { /* In window */
+			/*
+			 * If more than 64-bit anti-replay window,
+			 * use slow shift routine
+			 */
+			wptr = window + (shift >> WORD_SHIFT);
+			*wptr <<= shift;
+			*wptr |= 1ull;
+		} else {
+			/* No special handling of window size > 64 */
+			wptr = window + ((winsz - 1) >> WORD_SHIFT);
+			/*
+			 * Zero out the whole window (especially for
+			 * bigger than 64b window) till the last 64b word
+			 * as the incoming sequence number minus
+			 * base sequence is more than the window size.
+			 */
+			while (window != wptr)
+				*window++ = 0ull;
+			/*
+			 * Set the last bit (of the window) to 1
+			 * as that corresponds to the base sequence number.
+			 * Now any incoming sequence number which is
+			 * (base - window size - 1) will pass anti-replay check
+			 */
+			*wptr = 1ull;
+		}
+		/*
+		 * Set the base to incoming sequence number as
+		 * that is the biggest sequence number seen yet
+		 */
+		ar->base = seq;
+		return 0;
+	}
+
+	bit_pos = base - seq;
+
+	/* If seq falls behind the window, return failure */
+	if (bit_pos >= winsz)
+		return IPSEC_ANTI_REPLAY_FAILED;
+
+	/* seq is within anti-replay window */
+	wptr = window + ((winsz - bit_pos - 1) >> WORD_SHIFT);
+	bit_pos &= WORD_MASK;
+
+	/* Check if this is a replayed packet */
+	if (*wptr & ((1ull) << bit_pos))
+		return IPSEC_ANTI_REPLAY_FAILED;
+
+	/* mark as seen */
+	*wptr |= ((1ull) << bit_pos);
+	return 0;
+
+slow_shift:
+	if (likely(seq > base)) {
+		uint32_t i;
+
+		shift = seq - base;
+		if (unlikely(shift >= winsz)) {
+			/*
+			 * shift is bigger than the window,
+			 * so just zero out everything
+			 */
+			for (i = 0; i < winwords; i++)
+				window[i] = 0;
+winupdate:
+			/* Find out the word */
+			seqword = ((seq - 1) % ex_winsz) >> WORD_SHIFT;
+
+			/* Find out the bit in the word */
+			bit_pos = (seq - 1) & WORD_MASK;
+
+			/*
+			 * Set the bit corresponding to sequence number
+			 * in window to mark it as received
+			 */
+			window[seqword] |= (1ull << (63 - bit_pos));
+
+			/* wint and winb range from 1 to ex_winsz */
+			ar->wint = ((wint + shift - 1) % ex_winsz) + 1;
+			ar->winb = ((winb + shift - 1) % ex_winsz) + 1;
+
+			ar->base = seq;
+			return 0;
+		}
+
+		/*
+		 * New sequence number is bigger than the base but
+		 * it's not bigger than base + window size
+		 */
+
+		shiftwords = ((wint + shift - 1) >> WORD_SHIFT) -
+			     ((wint - 1) >> WORD_SHIFT);
+		if (unlikely(shiftwords)) {
+			tmp = (wint + WORD_SIZE - 1) / WORD_SIZE;
+			for (i = 0; i < shiftwords; i++) {
+				tmp %= winwords;
+				window[tmp++] = 0;
+			}
+		}
+
+		goto winupdate;
+	}
+
+	/* Sequence number is before the window */
+	if (unlikely((seq + winsz) <= base))
+		return IPSEC_ANTI_REPLAY_FAILED;
+
+	/* Sequence number is within the window */
+
+	/* Find out the word */
+	seqword = ((seq - 1) % ex_winsz) >> WORD_SHIFT;
+
+	/* Find out the bit in the word */
+	bit_pos = (seq - 1) & WORD_MASK;
+
+	/* Check if this is a replayed packet */
+	if (window[seqword] & (1ull << (63 - bit_pos)))
+		return IPSEC_ANTI_REPLAY_FAILED;
+
+	/*
+	 * Set the bit corresponding to sequence number
+	 * in window to mark it as received
+	 */
+	window[seqword] |= (1ull << (63 - bit_pos));
+
+	return 0;
+}
+
+#endif /* __CNXK_SECURITY_AR_H__ */
-- 
2.8.4