+/**
+ * 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;
+ struct replay_sqn *rsn;
+
+ n = sa->sqn.inb.wridx;
+
+ /* no active writers */
+ RTE_ASSERT(n == sa->sqn.inb.rdidx);
+
+ if (!SQN_ATOMIC(sa))
+ return sa->sqn.inb.rsn[n];
+
+ k = REPLAY_SQN_NEXT(n);
+ sa->sqn.inb.wridx = k;
+
+ rsn = sa->sqn.inb.rsn[k];
+ rte_rwlock_write_lock(&rsn->rwl);
+ rsn_copy(sa, k, n);
+
+ return rsn;
+}
+
+/**
+ * Finish RSN update.
+ */
+static inline void
+rsn_update_finish(struct rte_ipsec_sa *sa, struct replay_sqn *rsn)
+{
+ uint32_t n;
+
+ if (!SQN_ATOMIC(sa))
+ return;
+
+ n = sa->sqn.inb.wridx;
+ RTE_ASSERT(n != sa->sqn.inb.rdidx);
+ RTE_ASSERT(rsn - sa->sqn.inb.rsn == n);
+
+ rte_rwlock_write_unlock(&rsn->rwl);
+ sa->sqn.inb.rdidx = n;
+}
+
+