1 files changed, 145 insertions, 0 deletions
diff --git a/drivers/net/ovpn/crypto.h b/drivers/net/ovpn/crypto.h
new file mode 100644
index 000000000000..0e284fec3a75
--- /dev/null
+++ b/drivers/net/ovpn/crypto.h
@@ -0,0 +1,145 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*  OpenVPN data channel offload
+ *
+ *  Copyright (C) 2020-2025 OpenVPN, Inc.
+ *
+ *  Author:	James Yonan <james@openvpn.net>
+ *		Antonio Quartulli <antonio@openvpn.net>
+ */
+
+#ifndef _NET_OVPN_OVPNCRYPTO_H_
+#define _NET_OVPN_OVPNCRYPTO_H_
+
+#include "pktid.h"
+#include "proto.h"
+
+/* info needed for both encrypt and decrypt directions */
+struct ovpn_key_direction {
+	const u8 *cipher_key;
+	size_t cipher_key_size;
+	const u8 *nonce_tail; /* only needed for GCM modes */
+	size_t nonce_tail_size; /* only needed for GCM modes */
+};
+
+/* all info for a particular symmetric key (primary or secondary) */
+struct ovpn_key_config {
+	enum ovpn_cipher_alg cipher_alg;
+	u8 key_id;
+	struct ovpn_key_direction encrypt;
+	struct ovpn_key_direction decrypt;
+};
+
+/* used to pass settings from netlink to the crypto engine */
+struct ovpn_peer_key_reset {
+	enum ovpn_key_slot slot;
+	struct ovpn_key_config key;
+};
+
+struct ovpn_crypto_key_slot {
+	u8 key_id;
+
+	struct crypto_aead *encrypt;
+	struct crypto_aead *decrypt;
+	u8 nonce_tail_xmit[OVPN_NONCE_TAIL_SIZE];
+	u8 nonce_tail_recv[OVPN_NONCE_TAIL_SIZE];
+
+	struct ovpn_pktid_recv pid_recv ____cacheline_aligned_in_smp;
+	struct ovpn_pktid_xmit pid_xmit ____cacheline_aligned_in_smp;
+	struct kref refcount;
+	struct rcu_head rcu;
+};
+
+struct ovpn_crypto_state {
+	struct ovpn_crypto_key_slot __rcu *slots[2];
+	u8 primary_idx;
+
+	/* protects primary and secondary slots */
+	spinlock_t lock;
+};
+
+static inline bool ovpn_crypto_key_slot_hold(struct ovpn_crypto_key_slot *ks)
+{
+	return kref_get_unless_zero(&ks->refcount);
+}
+
+static inline void ovpn_crypto_state_init(struct ovpn_crypto_state *cs)
+{
+	RCU_INIT_POINTER(cs->slots[0], NULL);
+	RCU_INIT_POINTER(cs->slots[1], NULL);
+	cs->primary_idx = 0;
+	spin_lock_init(&cs->lock);
+}
+
+static inline struct ovpn_crypto_key_slot *
+ovpn_crypto_key_id_to_slot(const struct ovpn_crypto_state *cs, u8 key_id)
+{
+	struct ovpn_crypto_key_slot *ks;
+	u8 idx;
+
+	if (unlikely(!cs))
+		return NULL;
+
+	rcu_read_lock();
+	idx = READ_ONCE(cs->primary_idx);
+	ks = rcu_dereference(cs->slots[idx]);
+	if (ks && ks->key_id == key_id) {
+		if (unlikely(!ovpn_crypto_key_slot_hold(ks)))
+			ks = NULL;
+		goto out;
+	}
+
+	ks = rcu_dereference(cs->slots[!idx]);
+	if (ks && ks->key_id == key_id) {
+		if (unlikely(!ovpn_crypto_key_slot_hold(ks)))
+			ks = NULL;
+		goto out;
+	}
+
+	/* when both key slots are occupied but no matching key ID is found, ks
+	 * has to be reset to NULL to avoid carrying a stale pointer
+	 */
+	ks = NULL;
+out:
+	rcu_read_unlock();
+
+	return ks;
+}
+
+static inline struct ovpn_crypto_key_slot *
+ovpn_crypto_key_slot_primary(const struct ovpn_crypto_state *cs)
+{
+	struct ovpn_crypto_key_slot *ks;
+
+	rcu_read_lock();
+	ks = rcu_dereference(cs->slots[cs->primary_idx]);
+	if (unlikely(ks && !ovpn_crypto_key_slot_hold(ks)))
+		ks = NULL;
+	rcu_read_unlock();
+
+	return ks;
+}
+
+void ovpn_crypto_key_slot_release(struct kref *kref);
+
+static inline void ovpn_crypto_key_slot_put(struct ovpn_crypto_key_slot *ks)
+{
+	kref_put(&ks->refcount, ovpn_crypto_key_slot_release);
+}
+
+int ovpn_crypto_state_reset(struct ovpn_crypto_state *cs,
+			    const struct ovpn_peer_key_reset *pkr);
+
+void ovpn_crypto_key_slot_delete(struct ovpn_crypto_state *cs,
+				 enum ovpn_key_slot slot);
+
+void ovpn_crypto_state_release(struct ovpn_crypto_state *cs);
+
+void ovpn_crypto_key_slots_swap(struct ovpn_crypto_state *cs);
+
+int ovpn_crypto_config_get(struct ovpn_crypto_state *cs,
+			   enum ovpn_key_slot slot,
+			   struct ovpn_key_config *keyconf);
+
+bool ovpn_crypto_kill_key(struct ovpn_crypto_state *cs, u8 key_id);
+
+#endif /* _NET_OVPN_OVPNCRYPTO_H_ */