+ uint32_t bit, bucket;
+
+ /* replay not enabled */
+ if (sa->replay.win_sz == 0)
+ return 0;
+
+ /* seq is larger than lastseq */
+ if (sqn > rsn->sqn)
+ return 0;
+
+ /* seq is outside window */
+ if (sqn == 0 || sqn + sa->replay.win_sz < rsn->sqn)
+ return -EINVAL;
+
+ /* seq is inside the window */
+ bit = sqn & WINDOW_BIT_LOC_MASK;
+ bucket = (sqn >> WINDOW_BUCKET_BITS) & sa->replay.bucket_index_mask;
+
+ /* already seen packet */
+ if (rsn->window[bucket] & ((uint64_t)1 << bit))
+ return -EINVAL;
+
+ return 0;
+}
+
+/**
+ * For outbound SA perform the sequence number update.
+ */
+static inline uint64_t
+esn_outb_update_sqn(struct rte_ipsec_sa *sa, uint32_t *num)
+{
+ uint64_t n, s, sqn;
+
+ n = *num;
+ if (SQN_ATOMIC(sa))
+ sqn = (uint64_t)rte_atomic64_add_return(&sa->sqn.outb.atom, n);
+ else {
+ sqn = sa->sqn.outb.raw + n;
+ sa->sqn.outb.raw = sqn;
+ }
+
+ /* overflow */
+ if (sqn > sa->sqn_mask) {
+ s = sqn - sa->sqn_mask;
+ *num = (s < n) ? n - s : 0;
+ }
+
+ return sqn - n;
+}
+
+/**
+ * For inbound SA perform the sequence number and replay window update.
+ */
+static inline int32_t
+esn_inb_update_sqn(struct replay_sqn *rsn, const struct rte_ipsec_sa *sa,
+ uint64_t sqn)
+{
+ uint32_t bit, bucket, last_bucket, new_bucket, diff, i;
+
+ /* handle ESN */
+ if (IS_ESN(sa))
+ sqn = reconstruct_esn(rsn->sqn, sqn, sa->replay.win_sz);
+
+ /* seq is outside window*/
+ if (sqn == 0 || sqn + sa->replay.win_sz < rsn->sqn)
+ return -EINVAL;
+
+ /* update the bit */
+ bucket = (sqn >> WINDOW_BUCKET_BITS);
+
+ /* check if the seq is within the range */
+ if (sqn > rsn->sqn) {
+ last_bucket = rsn->sqn >> WINDOW_BUCKET_BITS;
+ diff = bucket - last_bucket;
+ /* seq is way after the range of WINDOW_SIZE */
+ if (diff > sa->replay.nb_bucket)
+ diff = sa->replay.nb_bucket;
+
+ for (i = 0; i != diff; i++) {
+ new_bucket = (i + last_bucket + 1) &
+ sa->replay.bucket_index_mask;
+ rsn->window[new_bucket] = 0;
+ }
+ rsn->sqn = sqn;
+ }
+
+ bucket &= sa->replay.bucket_index_mask;
+ bit = (uint64_t)1 << (sqn & WINDOW_BIT_LOC_MASK);
+
+ /* already seen packet */
+ if (rsn->window[bucket] & bit)
+ return -EINVAL;
+
+ rsn->window[bucket] |= bit;
+ return 0;
+}
+
+/**
+ * To achieve ability to do multiple readers single writer for
+ * SA replay window information and sequence number (RSN)
+ * basic RCU schema is used:
+ * SA have 2 copies of RSN (one for readers, another for writers).
+ * Each RSN contains a rwlock that has to be grabbed (for read/write)
+ * to avoid races between readers and writer.
+ * Writer is responsible to make a copy or reader RSN, update it
+ * and mark newly updated RSN as readers one.
+ * That approach is intended to minimize contention and cache sharing
+ * between writer and readers.
+ */
+
+/**
+ * Copy replay window and SQN.
+ */
+static inline void
+rsn_copy(const struct rte_ipsec_sa *sa, uint32_t dst, uint32_t src)
+{
+ uint32_t i, n;
+ struct replay_sqn *d;
+ const struct replay_sqn *s;
+
+ d = sa->sqn.inb.rsn[dst];
+ s = sa->sqn.inb.rsn[src];
+
+ n = sa->replay.nb_bucket;
+
+ d->sqn = s->sqn;
+ for (i = 0; i != n; i++)
+ d->window[i] = s->window[i];
+}
+
+/**
+ * Get RSN for read-only access.
+ */
+static inline struct replay_sqn *
+rsn_acquire(struct rte_ipsec_sa *sa)
+{
+ uint32_t n;
+ struct replay_sqn *rsn;
+
+ n = sa->sqn.inb.rdidx;
+ rsn = sa->sqn.inb.rsn[n];
+
+ if (!SQN_ATOMIC(sa))
+ return rsn;
+
+ /* check there are no writers */
+ while (rte_rwlock_read_trylock(&rsn->rwl) < 0) {
+ rte_pause();
+ n = sa->sqn.inb.rdidx;
+ rsn = sa->sqn.inb.rsn[n];
+ rte_compiler_barrier();
+ }
+
+ return rsn;
+}
+
+/**
+ * Release read-only access for RSN.
+ */
+static inline void
+rsn_release(struct rte_ipsec_sa *sa, struct replay_sqn *rsn)
+{
+ if (SQN_ATOMIC(sa))
+ rte_rwlock_read_unlock(&rsn->rwl);
+}
+
+/**
+ * Start RSN update.
+ */
+static inline struct replay_sqn *
+rsn_update_start(struct rte_ipsec_sa *sa)
+{
+ uint32_t k, n;