2 files changed, 393 insertions, 0 deletions
diff --git a/include/net/psp/functions.h b/include/net/psp/functions.h
new file mode 100644
index 000000000000..ef7743664da3
--- /dev/null
+++ b/include/net/psp/functions.h
@@ -0,0 +1,209 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __NET_PSP_HELPERS_H
+#define __NET_PSP_HELPERS_H
+
+#include <linux/skbuff.h>
+#include <linux/rcupdate.h>
+#include <linux/udp.h>
+#include <net/sock.h>
+#include <net/tcp.h>
+#include <net/psp/types.h>
+
+struct inet_timewait_sock;
+
+/* Driver-facing API */
+struct psp_dev *
+psp_dev_create(struct net_device *netdev, struct psp_dev_ops *psd_ops,
+	       struct psp_dev_caps *psd_caps, void *priv_ptr);
+void psp_dev_unregister(struct psp_dev *psd);
+bool psp_dev_encapsulate(struct net *net, struct sk_buff *skb, __be32 spi,
+			 u8 ver, __be16 sport);
+int psp_dev_rcv(struct sk_buff *skb, u16 dev_id, u8 generation, bool strip_icv);
+
+/* Kernel-facing API */
+void psp_assoc_put(struct psp_assoc *pas);
+
+static inline void *psp_assoc_drv_data(struct psp_assoc *pas)
+{
+	return pas->drv_data;
+}
+
+#if IS_ENABLED(CONFIG_INET_PSP)
+unsigned int psp_key_size(u32 version);
+void psp_sk_assoc_free(struct sock *sk);
+void psp_twsk_init(struct inet_timewait_sock *tw, const struct sock *sk);
+void psp_twsk_assoc_free(struct inet_timewait_sock *tw);
+void psp_reply_set_decrypted(struct sk_buff *skb);
+
+static inline struct psp_assoc *psp_sk_assoc(const struct sock *sk)
+{
+	return rcu_dereference_check(sk->psp_assoc, lockdep_sock_is_held(sk));
+}
+
+static inline void
+psp_enqueue_set_decrypted(struct sock *sk, struct sk_buff *skb)
+{
+	struct psp_assoc *pas;
+
+	pas = psp_sk_assoc(sk);
+	if (pas && pas->tx.spi)
+		skb->decrypted = 1;
+}
+
+static inline unsigned long
+__psp_skb_coalesce_diff(const struct sk_buff *one, const struct sk_buff *two,
+			unsigned long diffs)
+{
+	struct psp_skb_ext *a, *b;
+
+	a = skb_ext_find(one, SKB_EXT_PSP);
+	b = skb_ext_find(two, SKB_EXT_PSP);
+
+	diffs |= (!!a) ^ (!!b);
+	if (!diffs && unlikely(a))
+		diffs |= memcmp(a, b, sizeof(*a));
+	return diffs;
+}
+
+static inline bool
+psp_is_allowed_nondata(struct sk_buff *skb, struct psp_assoc *pas)
+{
+	bool fin = !!(TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN);
+	u32 end_seq = TCP_SKB_CB(skb)->end_seq;
+	u32 seq = TCP_SKB_CB(skb)->seq;
+	bool pure_fin;
+
+	pure_fin = fin && end_seq - seq == 1;
+
+	return seq == end_seq || (pure_fin && seq == pas->upgrade_seq);
+}
+
+static inline bool
+psp_pse_matches_pas(struct psp_skb_ext *pse, struct psp_assoc *pas)
+{
+	return pse && pas->rx.spi == pse->spi &&
+	       pas->generation == pse->generation &&
+	       pas->version == pse->version &&
+	       pas->dev_id == pse->dev_id;
+}
+
+static inline enum skb_drop_reason
+__psp_sk_rx_policy_check(struct sk_buff *skb, struct psp_assoc *pas)
+{
+	struct psp_skb_ext *pse = skb_ext_find(skb, SKB_EXT_PSP);
+
+	if (!pas)
+		return pse ? SKB_DROP_REASON_PSP_INPUT : 0;
+
+	if (likely(psp_pse_matches_pas(pse, pas))) {
+		if (unlikely(!pas->peer_tx))
+			pas->peer_tx = 1;
+
+		return 0;
+	}
+
+	if (!pse) {
+		if (!pas->tx.spi ||
+		    (!pas->peer_tx && psp_is_allowed_nondata(skb, pas)))
+			return 0;
+	}
+
+	return SKB_DROP_REASON_PSP_INPUT;
+}
+
+static inline enum skb_drop_reason
+psp_sk_rx_policy_check(struct sock *sk, struct sk_buff *skb)
+{
+	return __psp_sk_rx_policy_check(skb, psp_sk_assoc(sk));
+}
+
+static inline enum skb_drop_reason
+psp_twsk_rx_policy_check(struct inet_timewait_sock *tw, struct sk_buff *skb)
+{
+	return __psp_sk_rx_policy_check(skb, rcu_dereference(tw->psp_assoc));
+}
+
+static inline struct psp_assoc *psp_sk_get_assoc_rcu(const struct sock *sk)
+{
+	struct psp_assoc *pas;
+	int state;
+
+	state = READ_ONCE(sk->sk_state);
+	if (!sk_is_inet(sk) || state == TCP_NEW_SYN_RECV)
+		return NULL;
+
+	pas = state == TCP_TIME_WAIT ?
+		      rcu_dereference(inet_twsk(sk)->psp_assoc) :
+		      rcu_dereference(sk->psp_assoc);
+	return pas;
+}
+
+static inline struct psp_assoc *psp_skb_get_assoc_rcu(struct sk_buff *skb)
+{
+	if (!skb->decrypted || !skb->sk)
+		return NULL;
+
+	return psp_sk_get_assoc_rcu(skb->sk);
+}
+
+static inline unsigned int psp_sk_overhead(const struct sock *sk)
+{
+	int psp_encap = sizeof(struct udphdr) + PSP_HDR_SIZE + PSP_TRL_SIZE;
+	bool has_psp = rcu_access_pointer(sk->psp_assoc);
+
+	return has_psp ? psp_encap : 0;
+}
+#else
+static inline void psp_sk_assoc_free(struct sock *sk) { }
+static inline void
+psp_twsk_init(struct inet_timewait_sock *tw, const struct sock *sk) { }
+static inline void psp_twsk_assoc_free(struct inet_timewait_sock *tw) { }
+static inline void
+psp_reply_set_decrypted(struct sk_buff *skb) { }
+
+static inline struct psp_assoc *psp_sk_assoc(const struct sock *sk)
+{
+	return NULL;
+}
+
+static inline void
+psp_enqueue_set_decrypted(struct sock *sk, struct sk_buff *skb) { }
+
+static inline unsigned long
+__psp_skb_coalesce_diff(const struct sk_buff *one, const struct sk_buff *two,
+			unsigned long diffs)
+{
+	return diffs;
+}
+
+static inline enum skb_drop_reason
+psp_sk_rx_policy_check(struct sock *sk, struct sk_buff *skb)
+{
+	return 0;
+}
+
+static inline enum skb_drop_reason
+psp_twsk_rx_policy_check(struct inet_timewait_sock *tw, struct sk_buff *skb)
+{
+	return 0;
+}
+
+static inline struct psp_assoc *psp_skb_get_assoc_rcu(struct sk_buff *skb)
+{
+	return NULL;
+}
+
+static inline unsigned int psp_sk_overhead(const struct sock *sk)
+{
+	return 0;
+}
+#endif
+
+static inline unsigned long
+psp_skb_coalesce_diff(const struct sk_buff *one, const struct sk_buff *two)
+{
+	return __psp_skb_coalesce_diff(one, two, 0);
+}
+
+#endif /* __NET_PSP_HELPERS_H */
diff --git a/include/net/psp/types.h b/include/net/psp/types.h
new file mode 100644
index 000000000000..31cee64b7c86
--- /dev/null
+++ b/include/net/psp/types.h
@@ -0,0 +1,184 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef __NET_PSP_H
+#define __NET_PSP_H
+
+#include <linux/mutex.h>
+#include <linux/refcount.h>
+
+struct netlink_ext_ack;
+
+#define PSP_DEFAULT_UDP_PORT	1000
+
+struct psphdr {
+	u8	nexthdr;
+	u8	hdrlen;
+	u8	crypt_offset;
+	u8	verfl;
+	__be32	spi;
+	__be64	iv;
+	__be64	vc[]; /* optional */
+};
+
+#define PSP_ENCAP_HLEN (sizeof(struct udphdr) + sizeof(struct psphdr))
+
+#define PSP_SPI_KEY_ID		GENMASK(30, 0)
+#define PSP_SPI_KEY_PHASE	BIT(31)
+
+#define PSPHDR_CRYPT_OFFSET	GENMASK(5, 0)
+
+#define PSPHDR_VERFL_SAMPLE	BIT(7)
+#define PSPHDR_VERFL_DROP	BIT(6)
+#define PSPHDR_VERFL_VERSION	GENMASK(5, 2)
+#define PSPHDR_VERFL_VIRT	BIT(1)
+#define PSPHDR_VERFL_ONE	BIT(0)
+
+#define PSP_HDRLEN_NOOPT	((sizeof(struct psphdr) - 8) / 8)
+
+/**
+ * struct psp_dev_config - PSP device configuration
+ * @versions: PSP versions enabled on the device
+ */
+struct psp_dev_config {
+	u32 versions;
+};
+
+/**
+ * struct psp_dev - PSP device struct
+ * @main_netdev: original netdevice of this PSP device
+ * @ops:	driver callbacks
+ * @caps:	device capabilities
+ * @drv_priv:	driver priv pointer
+ * @lock:	instance lock, protects all fields
+ * @refcnt:	reference count for the instance
+ * @id:		instance id
+ * @generation:	current generation of the device key
+ * @config:	current device configuration
+ * @active_assocs:	list of registered associations
+ * @prev_assocs:	associations which use old (but still usable)
+ *			device key
+ * @stale_assocs:	associations which use a rotated out key
+ *
+ * @rcu:	RCU head for freeing the structure
+ */
+struct psp_dev {
+	struct net_device *main_netdev;
+
+	struct psp_dev_ops *ops;
+	struct psp_dev_caps *caps;
+	void *drv_priv;
+
+	struct mutex lock;
+	refcount_t refcnt;
+
+	u32 id;
+
+	u8 generation;
+
+	struct psp_dev_config config;
+
+	struct list_head active_assocs;
+	struct list_head prev_assocs;
+	struct list_head stale_assocs;
+
+	struct rcu_head rcu;
+};
+
+#define PSP_GEN_VALID_MASK	0x7f
+
+/**
+ * struct psp_dev_caps - PSP device capabilities
+ */
+struct psp_dev_caps {
+	/**
+	 * @versions: mask of supported PSP versions
+	 * Set this field to 0 to indicate PSP is not supported at all.
+	 */
+	u32 versions;
+
+	/**
+	 * @assoc_drv_spc: size of driver-specific state in Tx assoc
+	 * Determines the size of struct psp_assoc::drv_data
+	 */
+	u32 assoc_drv_spc;
+};
+
+#define PSP_MAX_KEY	32
+
+#define PSP_HDR_SIZE	16	/* We don't support optional fields, yet */
+#define PSP_TRL_SIZE	16	/* AES-GCM/GMAC trailer size */
+
+struct psp_skb_ext {
+	__be32 spi;
+	u16 dev_id;
+	u8 generation;
+	u8 version;
+};
+
+struct psp_key_parsed {
+	__be32 spi;
+	u8 key[PSP_MAX_KEY];
+};
+
+struct psp_assoc {
+	struct psp_dev *psd;
+
+	u16 dev_id;
+	u8 generation;
+	u8 version;
+	u8 peer_tx;
+
+	u32 upgrade_seq;
+
+	struct psp_key_parsed tx;
+	struct psp_key_parsed rx;
+
+	refcount_t refcnt;
+	struct rcu_head rcu;
+	struct work_struct work;
+	struct list_head assocs_list;
+
+	u8 drv_data[] __aligned(8);
+};
+
+/**
+ * struct psp_dev_ops - netdev driver facing PSP callbacks
+ */
+struct psp_dev_ops {
+	/**
+	 * @set_config: set configuration of a PSP device
+	 * Driver can inspect @psd->config for the previous configuration.
+	 * Core will update @psd->config with @config on success.
+	 */
+	int (*set_config)(struct psp_dev *psd, struct psp_dev_config *conf,
+			  struct netlink_ext_ack *extack);
+
+	/**
+	 * @key_rotate: rotate the device key
+	 */
+	int (*key_rotate)(struct psp_dev *psd, struct netlink_ext_ack *extack);
+
+	/**
+	 * @rx_spi_alloc: allocate an Rx SPI+key pair
+	 * Allocate an Rx SPI and resulting derived key.
+	 * This key should remain valid until key rotation.
+	 */
+	int (*rx_spi_alloc)(struct psp_dev *psd, u32 version,
+			    struct psp_key_parsed *assoc,
+			    struct netlink_ext_ack *extack);
+
+	/**
+	 * @tx_key_add: add a Tx key to the device
+	 * Install an association in the device. Core will allocate space
+	 * for the driver to use at drv_data.
+	 */
+	int (*tx_key_add)(struct psp_dev *psd, struct psp_assoc *pas,
+			  struct netlink_ext_ack *extack);
+	/**
+	 * @tx_key_del: remove a Tx key from the device
+	 * Remove an association from the device.
+	 */
+	void (*tx_key_del)(struct psp_dev *psd, struct psp_assoc *pas);
+};
+
+#endif /* __NET_PSP_H */