[RFC PATCH bpf-next 0/5] net/smc: Introduce BPF injection capability

[RFC PATCH bpf-next 0/5] net/smc: Introduce BPF injection capability

[D. Wythe]

From: "D. Wythe" <alibuda@linux.alibaba.com>

This patches attempt to introduce BPF injection capability for SMC,
and add selftest to ensure code stability.

As we all know that the SMC protocol is not suitable for all scenarios,
especially for short-lived. However, for most applications, they cannot
guarantee that there are no such scenarios at all. Therefore, apps
may need some specific strategies to decide shall we need to use SMC
or not, for example, apps can limit the scope of the SMC to a specific
IP address or port.

Based on the consideration of transparent replacement, we hope that apps
can remain transparent even if they need to formulate some specific
strategies for SMC using. That is, do not need to recompile their code.

On the other hand, we need to ensure the scalability of strategies
implementation. Although it is simple to use socket options or sysctl,
it will bring more complexity to subsequent expansion.

Fortunately, BPF can solve these concerns very well, users can write
thire own strategies in eBPF to choose whether to use SMC or not.
And it's quite easy for them to modify their strategies in the future.

This patches implement injection capability for SMC via struct_ops.
In that way, we can add new injection scenarios in the future.

D. Wythe (5):
  net/smc: move smc_sock related structure definition
  net/smc: net/smc: allow smc to negotiate protocols on policies
  net/smc: allow set or get smc negotiator by sockopt
  bpf: add smc negotiator support in BPF struct_ops
  bpf/selftests: add selftest for SMC bpf capability

 include/net/smc.h                                | 268 +++++++++++++++++
 include/uapi/linux/smc.h                         |   1 +
 kernel/bpf/bpf_struct_ops_types.h                |   4 +
 net/Makefile                                     |   1 +
 net/smc/Kconfig                                  |  13 +
 net/smc/af_smc.c                                 | 203 ++++++++++---
 net/smc/bpf_smc.c                                | 359 +++++++++++++++++++++++
 net/smc/smc.h                                    | 224 --------------
 tools/testing/selftests/bpf/prog_tests/bpf_smc.c | 107 +++++++
 tools/testing/selftests/bpf/progs/bpf_smc.c      | 265 +++++++++++++++++
 10 files changed, 1186 insertions(+), 259 deletions(-)
 create mode 100644 net/smc/bpf_smc.c
 create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_smc.c
 create mode 100644 tools/testing/selftests/bpf/progs/bpf_smc.c

-- 
1.8.3.1

[RFC PATCH bpf-next 1/5] net/smc: move smc_sock related structure definition

[D. Wythe]

From: "D. Wythe" <alibuda@linux.alibaba.com>

This patch only try to move the definition of smc_sock and its
related structure, from et/smc/smc.h to include/net/smc/smc.h.
In that way can ebpf generate the BTF ID corresponding to our
structure.

Of course, we can also choose to hide the structure and only to
expose an intermediate structure, but it requires an additional
transformation. If we need to obtain some information frequently, this
may cause some performance problems.

Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
---
 include/net/smc.h | 225 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 net/smc/smc.h     | 224 -----------------------------------------------------
 2 files changed, 225 insertions(+), 224 deletions(-)

diff --git a/include/net/smc.h b/include/net/smc.h
index 597cb93..eccbd37 100644
--- a/include/net/smc.h
+++ b/include/net/smc.h
@@ -11,12 +11,17 @@
 #ifndef _SMC_H
 #define _SMC_H
 
+#include <net/inet_connection_sock.h>
 #include <linux/device.h>
 #include <linux/spinlock.h>
 #include <linux/types.h>
 #include <linux/wait.h>
 #include "linux/ism.h"
 
+#ifdef ATOMIC64_INIT
+#define KERNEL_HAS_ATOMIC64
+#endif
+
 struct sock;
 
 #define SMC_MAX_PNETID_LEN	16	/* Max. length of PNET id */
@@ -90,4 +95,224 @@ struct smcd_dev {
 	u8 going_away : 1;
 };
 
+struct smc_wr_rx_hdr {	/* common prefix part of LLC and CDC to demultiplex */
+	union {
+		u8 type;
+#if defined(__BIG_ENDIAN_BITFIELD)
+		struct {
+			u8 llc_version:4,
+			   llc_type:4;
+		};
+#elif defined(__LITTLE_ENDIAN_BITFIELD)
+		struct {
+			u8 llc_type:4,
+			   llc_version:4;
+		};
+#endif
+	};
+} __aligned(1);
+
+struct smc_cdc_conn_state_flags {
+#if defined(__BIG_ENDIAN_BITFIELD)
+	u8	peer_done_writing : 1;	/* Sending done indicator */
+	u8	peer_conn_closed : 1;	/* Peer connection closed indicator */
+	u8	peer_conn_abort : 1;	/* Abnormal close indicator */
+	u8	reserved : 5;
+#elif defined(__LITTLE_ENDIAN_BITFIELD)
+	u8	reserved : 5;
+	u8	peer_conn_abort : 1;
+	u8	peer_conn_closed : 1;
+	u8	peer_done_writing : 1;
+#endif
+};
+
+struct smc_cdc_producer_flags {
+#if defined(__BIG_ENDIAN_BITFIELD)
+	u8	write_blocked : 1;	/* Writing Blocked, no rx buf space */
+	u8	urg_data_pending : 1;	/* Urgent Data Pending */
+	u8	urg_data_present : 1;	/* Urgent Data Present */
+	u8	cons_curs_upd_req : 1;	/* cursor update requested */
+	u8	failover_validation : 1;/* message replay due to failover */
+	u8	reserved : 3;
+#elif defined(__LITTLE_ENDIAN_BITFIELD)
+	u8	reserved : 3;
+	u8	failover_validation : 1;
+	u8	cons_curs_upd_req : 1;
+	u8	urg_data_present : 1;
+	u8	urg_data_pending : 1;
+	u8	write_blocked : 1;
+#endif
+};
+
+/* in host byte order */
+union smc_host_cursor {	/* SMC cursor - an offset in an RMBE */
+	struct {
+		u16	reserved;
+		u16	wrap;		/* window wrap sequence number */
+		u32	count;		/* cursor (= offset) part */
+	};
+#ifdef KERNEL_HAS_ATOMIC64
+	atomic64_t		acurs;	/* for atomic processing */
+#else
+	u64			acurs;	/* for atomic processing */
+#endif
+} __aligned(8);
+
+/* in host byte order, except for flag bitfields in network byte order */
+struct smc_host_cdc_msg {		/* Connection Data Control message */
+	struct smc_wr_rx_hdr		common; /* .type = 0xFE */
+	u8				len;	/* length = 44 */
+	u16				seqno;	/* connection seq # */
+	u32				token;	/* alert_token */
+	union smc_host_cursor		prod;		/* producer cursor */
+	union smc_host_cursor		cons;		/* consumer cursor,
+							 * piggy backed "ack"
+							 */
+	struct smc_cdc_producer_flags	prod_flags;	/* conn. tx/rx status */
+	struct smc_cdc_conn_state_flags	conn_state_flags; /* peer conn. status*/
+	u8				reserved[18];
+} __aligned(8);
+
+enum smc_urg_state {
+	SMC_URG_VALID	= 1,			/* data present */
+	SMC_URG_NOTYET	= 2,			/* data pending */
+	SMC_URG_READ	= 3,			/* data was already read */
+};
+
+struct smc_connection {
+	struct rb_node		alert_node;
+	struct smc_link_group	*lgr;		/* link group of connection */
+	struct smc_link		*lnk;		/* assigned SMC-R link */
+	u32			alert_token_local; /* unique conn. id */
+	u8			peer_rmbe_idx;	/* from tcp handshake */
+	int			peer_rmbe_size;	/* size of peer rx buffer */
+	atomic_t		peer_rmbe_space;/* remaining free bytes in peer
+						 * rmbe
+						 */
+	int			rtoken_idx;	/* idx to peer RMB rkey/addr */
+
+	struct smc_buf_desc	*sndbuf_desc;	/* send buffer descriptor */
+	struct smc_buf_desc	*rmb_desc;	/* RMBE descriptor */
+	int			rmbe_size_short;/* compressed notation */
+	int			rmbe_update_limit;
+						/* lower limit for consumer
+						 * cursor update
+						 */
+
+	struct smc_host_cdc_msg	local_tx_ctrl;	/* host byte order staging
+						 * buffer for CDC msg send
+						 * .prod cf. TCP snd_nxt
+						 * .cons cf. TCP sends ack
+						 */
+	union smc_host_cursor	local_tx_ctrl_fin;
+						/* prod crsr - confirmed by peer
+						 */
+	union smc_host_cursor	tx_curs_prep;	/* tx - prepared data
+						 * snd_max..wmem_alloc
+						 */
+	union smc_host_cursor	tx_curs_sent;	/* tx - sent data
+						 * snd_nxt ?
+						 */
+	union smc_host_cursor	tx_curs_fin;	/* tx - confirmed by peer
+						 * snd-wnd-begin ?
+						 */
+	atomic_t		sndbuf_space;	/* remaining space in sndbuf */
+	u16			tx_cdc_seq;	/* sequence # for CDC send */
+	u16			tx_cdc_seq_fin;	/* sequence # - tx completed */
+	spinlock_t		send_lock;	/* protect wr_sends */
+	atomic_t		cdc_pend_tx_wr; /* number of pending tx CDC wqe
+						 * - inc when post wqe,
+						 * - dec on polled tx cqe
+						 */
+	wait_queue_head_t	cdc_pend_tx_wq; /* wakeup on no cdc_pend_tx_wr*/
+	atomic_t		tx_pushing;     /* nr_threads trying tx push */
+	struct delayed_work	tx_work;	/* retry of smc_cdc_msg_send */
+	u32			tx_off;		/* base offset in peer rmb */
+
+	struct smc_host_cdc_msg	local_rx_ctrl;	/* filled during event_handl.
+						 * .prod cf. TCP rcv_nxt
+						 * .cons cf. TCP snd_una
+						 */
+	union smc_host_cursor	rx_curs_confirmed; /* confirmed to peer
+						    * source of snd_una ?
+						    */
+	union smc_host_cursor	urg_curs;	/* points at urgent byte */
+	enum smc_urg_state	urg_state;
+	bool			urg_tx_pend;	/* urgent data staged */
+	bool			urg_rx_skip_pend;
+						/* indicate urgent oob data
+						 * read, but previous regular
+						 * data still pending
+						 */
+	char			urg_rx_byte;	/* urgent byte */
+	bool			tx_in_release_sock;
+						/* flush pending tx data in
+						 * sock release_cb()
+						 */
+	atomic_t		bytes_to_rcv;	/* arrived data,
+						 * not yet received
+						 */
+	atomic_t		splice_pending;	/* number of spliced bytes
+						 * pending processing
+						 */
+#ifndef KERNEL_HAS_ATOMIC64
+	spinlock_t		acurs_lock;	/* protect cursors */
+#endif
+	struct work_struct	close_work;	/* peer sent some closing */
+	struct work_struct	abort_work;	/* abort the connection */
+	struct tasklet_struct	rx_tsklet;	/* Receiver tasklet for SMC-D */
+	u8			rx_off;		/* receive offset:
+						 * 0 for SMC-R, 32 for SMC-D
+						 */
+	u64			peer_token;	/* SMC-D token of peer */
+	u8			killed : 1;	/* abnormal termination */
+	u8			freed : 1;	/* normal termiation */
+	u8			out_of_sync : 1; /* out of sync with peer */
+};
+
+struct smc_sock {				/* smc sock container */
+	struct sock		sk;
+	struct socket		*clcsock;	/* internal tcp socket */
+	void			(*clcsk_state_change)(struct sock *sk);
+						/* original stat_change fct. */
+	void			(*clcsk_data_ready)(struct sock *sk);
+						/* original data_ready fct. */
+	void			(*clcsk_write_space)(struct sock *sk);
+						/* original write_space fct. */
+	void			(*clcsk_error_report)(struct sock *sk);
+						/* original error_report fct. */
+	struct smc_connection	conn;		/* smc connection */
+	struct smc_sock		*listen_smc;	/* listen parent */
+	struct work_struct	connect_work;	/* handle non-blocking connect*/
+	struct work_struct	tcp_listen_work;/* handle tcp socket accepts */
+	struct work_struct	smc_listen_work;/* prepare new accept socket */
+	struct list_head	accept_q;	/* sockets to be accepted */
+	spinlock_t		accept_q_lock;	/* protects accept_q */
+	bool			limit_smc_hs;	/* put constraint on handshake */
+	bool			use_fallback;	/* fallback to tcp */
+	int			fallback_rsn;	/* reason for fallback */
+	u32			peer_diagnosis; /* decline reason from peer */
+	atomic_t                queued_smc_hs;  /* queued smc handshakes */
+	struct inet_connection_sock_af_ops		af_ops;
+	const struct inet_connection_sock_af_ops	*ori_af_ops;
+						/* original af ops */
+	int			sockopt_defer_accept;
+						/* sockopt TCP_DEFER_ACCEPT
+						 * value
+						 */
+	u8			wait_close_tx_prepared : 1;
+						/* shutdown wr or close
+						 * started, waiting for unsent
+						 * data to be sent
+						 */
+	u8			connect_nonblock : 1;
+						/* non-blocking connect in
+						 * flight
+						 */
+	struct mutex            clcsock_release_lock;
+						/* protects clcsock of a listen
+						 * socket
+						 */
+};
+
 #endif	/* _SMC_H */
diff --git a/net/smc/smc.h b/net/smc/smc.h
index 5ed765e..6f27f40 100644
--- a/net/smc/smc.h
+++ b/net/smc/smc.h
@@ -34,10 +34,6 @@
 extern struct proto smc_proto;
 extern struct proto smc_proto6;
 
-#ifdef ATOMIC64_INIT
-#define KERNEL_HAS_ATOMIC64
-#endif
-
 enum smc_state {		/* possible states of an SMC socket */
 	SMC_ACTIVE	= 1,
 	SMC_INIT	= 2,
@@ -57,232 +53,12 @@ enum smc_state {		/* possible states of an SMC socket */
 
 struct smc_link_group;
 
-struct smc_wr_rx_hdr {	/* common prefix part of LLC and CDC to demultiplex */
-	union {
-		u8 type;
-#if defined(__BIG_ENDIAN_BITFIELD)
-		struct {
-			u8 llc_version:4,
-			   llc_type:4;
-		};
-#elif defined(__LITTLE_ENDIAN_BITFIELD)
-		struct {
-			u8 llc_type:4,
-			   llc_version:4;
-		};
-#endif
-	};
-} __aligned(1);
-
-struct smc_cdc_conn_state_flags {
-#if defined(__BIG_ENDIAN_BITFIELD)
-	u8	peer_done_writing : 1;	/* Sending done indicator */
-	u8	peer_conn_closed : 1;	/* Peer connection closed indicator */
-	u8	peer_conn_abort : 1;	/* Abnormal close indicator */
-	u8	reserved : 5;
-#elif defined(__LITTLE_ENDIAN_BITFIELD)
-	u8	reserved : 5;
-	u8	peer_conn_abort : 1;
-	u8	peer_conn_closed : 1;
-	u8	peer_done_writing : 1;
-#endif
-};
-
-struct smc_cdc_producer_flags {
-#if defined(__BIG_ENDIAN_BITFIELD)
-	u8	write_blocked : 1;	/* Writing Blocked, no rx buf space */
-	u8	urg_data_pending : 1;	/* Urgent Data Pending */
-	u8	urg_data_present : 1;	/* Urgent Data Present */
-	u8	cons_curs_upd_req : 1;	/* cursor update requested */
-	u8	failover_validation : 1;/* message replay due to failover */
-	u8	reserved : 3;
-#elif defined(__LITTLE_ENDIAN_BITFIELD)
-	u8	reserved : 3;
-	u8	failover_validation : 1;
-	u8	cons_curs_upd_req : 1;
-	u8	urg_data_present : 1;
-	u8	urg_data_pending : 1;
-	u8	write_blocked : 1;
-#endif
-};
-
-/* in host byte order */
-union smc_host_cursor {	/* SMC cursor - an offset in an RMBE */
-	struct {
-		u16	reserved;
-		u16	wrap;		/* window wrap sequence number */
-		u32	count;		/* cursor (= offset) part */
-	};
-#ifdef KERNEL_HAS_ATOMIC64
-	atomic64_t		acurs;	/* for atomic processing */
-#else
-	u64			acurs;	/* for atomic processing */
-#endif
-} __aligned(8);
-
-/* in host byte order, except for flag bitfields in network byte order */
-struct smc_host_cdc_msg {		/* Connection Data Control message */
-	struct smc_wr_rx_hdr		common; /* .type = 0xFE */
-	u8				len;	/* length = 44 */
-	u16				seqno;	/* connection seq # */
-	u32				token;	/* alert_token */
-	union smc_host_cursor		prod;		/* producer cursor */
-	union smc_host_cursor		cons;		/* consumer cursor,
-							 * piggy backed "ack"
-							 */
-	struct smc_cdc_producer_flags	prod_flags;	/* conn. tx/rx status */
-	struct smc_cdc_conn_state_flags	conn_state_flags; /* peer conn. status*/
-	u8				reserved[18];
-} __aligned(8);
-
-enum smc_urg_state {
-	SMC_URG_VALID	= 1,			/* data present */
-	SMC_URG_NOTYET	= 2,			/* data pending */
-	SMC_URG_READ	= 3,			/* data was already read */
-};
-
 struct smc_mark_woken {
 	bool woken;
 	void *key;
 	wait_queue_entry_t wait_entry;
 };
 
-struct smc_connection {
-	struct rb_node		alert_node;
-	struct smc_link_group	*lgr;		/* link group of connection */
-	struct smc_link		*lnk;		/* assigned SMC-R link */
-	u32			alert_token_local; /* unique conn. id */
-	u8			peer_rmbe_idx;	/* from tcp handshake */
-	int			peer_rmbe_size;	/* size of peer rx buffer */
-	atomic_t		peer_rmbe_space;/* remaining free bytes in peer
-						 * rmbe
-						 */
-	int			rtoken_idx;	/* idx to peer RMB rkey/addr */
-
-	struct smc_buf_desc	*sndbuf_desc;	/* send buffer descriptor */
-	struct smc_buf_desc	*rmb_desc;	/* RMBE descriptor */
-	int			rmbe_size_short;/* compressed notation */
-	int			rmbe_update_limit;
-						/* lower limit for consumer
-						 * cursor update
-						 */
-
-	struct smc_host_cdc_msg	local_tx_ctrl;	/* host byte order staging
-						 * buffer for CDC msg send
-						 * .prod cf. TCP snd_nxt
-						 * .cons cf. TCP sends ack
-						 */
-	union smc_host_cursor	local_tx_ctrl_fin;
-						/* prod crsr - confirmed by peer
-						 */
-	union smc_host_cursor	tx_curs_prep;	/* tx - prepared data
-						 * snd_max..wmem_alloc
-						 */
-	union smc_host_cursor	tx_curs_sent;	/* tx - sent data
-						 * snd_nxt ?
-						 */
-	union smc_host_cursor	tx_curs_fin;	/* tx - confirmed by peer
-						 * snd-wnd-begin ?
-						 */
-	atomic_t		sndbuf_space;	/* remaining space in sndbuf */
-	u16			tx_cdc_seq;	/* sequence # for CDC send */
-	u16			tx_cdc_seq_fin;	/* sequence # - tx completed */
-	spinlock_t		send_lock;	/* protect wr_sends */
-	atomic_t		cdc_pend_tx_wr; /* number of pending tx CDC wqe
-						 * - inc when post wqe,
-						 * - dec on polled tx cqe
-						 */
-	wait_queue_head_t	cdc_pend_tx_wq; /* wakeup on no cdc_pend_tx_wr*/
-	atomic_t		tx_pushing;     /* nr_threads trying tx push */
-	struct delayed_work	tx_work;	/* retry of smc_cdc_msg_send */
-	u32			tx_off;		/* base offset in peer rmb */
-
-	struct smc_host_cdc_msg	local_rx_ctrl;	/* filled during event_handl.
-						 * .prod cf. TCP rcv_nxt
-						 * .cons cf. TCP snd_una
-						 */
-	union smc_host_cursor	rx_curs_confirmed; /* confirmed to peer
-						    * source of snd_una ?
-						    */
-	union smc_host_cursor	urg_curs;	/* points at urgent byte */
-	enum smc_urg_state	urg_state;
-	bool			urg_tx_pend;	/* urgent data staged */
-	bool			urg_rx_skip_pend;
-						/* indicate urgent oob data
-						 * read, but previous regular
-						 * data still pending
-						 */
-	char			urg_rx_byte;	/* urgent byte */
-	bool			tx_in_release_sock;
-						/* flush pending tx data in
-						 * sock release_cb()
-						 */
-	atomic_t		bytes_to_rcv;	/* arrived data,
-						 * not yet received
-						 */
-	atomic_t		splice_pending;	/* number of spliced bytes
-						 * pending processing
-						 */
-#ifndef KERNEL_HAS_ATOMIC64
-	spinlock_t		acurs_lock;	/* protect cursors */
-#endif
-	struct work_struct	close_work;	/* peer sent some closing */
-	struct work_struct	abort_work;	/* abort the connection */
-	struct tasklet_struct	rx_tsklet;	/* Receiver tasklet for SMC-D */
-	u8			rx_off;		/* receive offset:
-						 * 0 for SMC-R, 32 for SMC-D
-						 */
-	u64			peer_token;	/* SMC-D token of peer */
-	u8			killed : 1;	/* abnormal termination */
-	u8			freed : 1;	/* normal termiation */
-	u8			out_of_sync : 1; /* out of sync with peer */
-};
-
-struct smc_sock {				/* smc sock container */
-	struct sock		sk;
-	struct socket		*clcsock;	/* internal tcp socket */
-	void			(*clcsk_state_change)(struct sock *sk);
-						/* original stat_change fct. */
-	void			(*clcsk_data_ready)(struct sock *sk);
-						/* original data_ready fct. */
-	void			(*clcsk_write_space)(struct sock *sk);
-						/* original write_space fct. */
-	void			(*clcsk_error_report)(struct sock *sk);
-						/* original error_report fct. */
-	struct smc_connection	conn;		/* smc connection */
-	struct smc_sock		*listen_smc;	/* listen parent */
-	struct work_struct	connect_work;	/* handle non-blocking connect*/
-	struct work_struct	tcp_listen_work;/* handle tcp socket accepts */
-	struct work_struct	smc_listen_work;/* prepare new accept socket */
-	struct list_head	accept_q;	/* sockets to be accepted */
-	spinlock_t		accept_q_lock;	/* protects accept_q */
-	bool			limit_smc_hs;	/* put constraint on handshake */
-	bool			use_fallback;	/* fallback to tcp */
-	int			fallback_rsn;	/* reason for fallback */
-	u32			peer_diagnosis; /* decline reason from peer */
-	atomic_t                queued_smc_hs;  /* queued smc handshakes */
-	struct inet_connection_sock_af_ops		af_ops;
-	const struct inet_connection_sock_af_ops	*ori_af_ops;
-						/* original af ops */
-	int			sockopt_defer_accept;
-						/* sockopt TCP_DEFER_ACCEPT
-						 * value
-						 */
-	u8			wait_close_tx_prepared : 1;
-						/* shutdown wr or close
-						 * started, waiting for unsent
-						 * data to be sent
-						 */
-	u8			connect_nonblock : 1;
-						/* non-blocking connect in
-						 * flight
-						 */
-	struct mutex            clcsock_release_lock;
-						/* protects clcsock of a listen
-						 * socket
-						 * */
-};
-
 static inline struct smc_sock *smc_sk(const struct sock *sk)
 {
 	return (struct smc_sock *)sk;
-- 
1.8.3.1

[RFC PATCH bpf-next 2/5] net/smc: net/smc: allow smc to negotiate protocols on policies

[D. Wythe]

From: "D. Wythe" <alibuda@linux.alibaba.com>

As we all know, the SMC protocol is not suitable for all scenarios,
especially for short-lived. However, for most applications, they cannot
guarantee that there are no such scenarios at all. Therefore, apps
may need some specific strategies to decide shall we need to use SMC
or not.

Just like the congestion control implementation in TCP, this patch
provides a generic negotiator implementation. If necessary,
we can provide different protocol negotiation strategies for
apps based on this implementation.

But most importantly, this patch provides the possibility of
eBPF injection, allowing users to implement their own protocol
negotiation policy in userspace.

Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
---
 include/net/smc.h |  43 ++++++++++++
 net/Makefile      |   1 +
 net/smc/Kconfig   |  13 ++++
 net/smc/af_smc.c  |  68 ++++++++++++++++++-
 net/smc/bpf_smc.c | 200 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 324 insertions(+), 1 deletion(-)
 create mode 100644 net/smc/bpf_smc.c

diff --git a/include/net/smc.h b/include/net/smc.h
index eccbd37..347050c 100644
--- a/include/net/smc.h
+++ b/include/net/smc.h
@@ -295,6 +295,8 @@ struct smc_sock {				/* smc sock container */
 	atomic_t                queued_smc_hs;  /* queued smc handshakes */
 	struct inet_connection_sock_af_ops		af_ops;
 	const struct inet_connection_sock_af_ops	*ori_af_ops;
+	/* protocol negotiator ops */
+	const struct smc_sock_negotiator_ops *negotiator_ops;
 						/* original af ops */
 	int			sockopt_defer_accept;
 						/* sockopt TCP_DEFER_ACCEPT
@@ -315,4 +317,45 @@ struct smc_sock {				/* smc sock container */
 						 */
 };
 
+#ifdef CONFIG_SMC_BPF
+
+#define SMC_NEGOTIATOR_NAME_MAX	(16)
+#define SMC_SOCK_CLOSED_TIMING	(0)
+
+/* BPF struct ops for smc protocol negotiator */
+struct smc_sock_negotiator_ops {
+
+	struct list_head	list;
+
+	/* ops name */
+	char		name[16];
+	/* key for name */
+	u32			key;
+
+	/* init with sk */
+	void (*init)(struct sock *sk);
+
+	/* release with sk */
+	void (*release)(struct sock *sk);
+
+	/* advice for negotiate */
+	int (*negotiate)(struct sock *sk);
+
+	/* info gathering timing */
+	void (*collect_info)(struct sock *sk, int timing);
+
+	/* module owner */
+	struct module *owner;
+};
+
+int smc_sock_register_negotiator_ops(struct smc_sock_negotiator_ops *ops);
+int smc_sock_update_negotiator_ops(struct smc_sock_negotiator_ops *ops,
+					  struct smc_sock_negotiator_ops *old_ops);
+void smc_sock_unregister_negotiator_ops(struct smc_sock_negotiator_ops *ops);
+int smc_sock_assign_negotiator_ops(struct smc_sock *smc, const char *name);
+void smc_sock_cleanup_negotiator_ops(struct smc_sock *smc, int in_release);
+void smc_sock_clone_negotiator_ops(struct sock *parent, struct sock *child);
+
+#endif
+
 #endif	/* _SMC_H */
diff --git a/net/Makefile b/net/Makefile
index 0914bea..a3b2d7a 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -52,6 +52,7 @@ obj-$(CONFIG_TIPC)		+= tipc/
 obj-$(CONFIG_NETLABEL)		+= netlabel/
 obj-$(CONFIG_IUCV)		+= iucv/
 obj-$(CONFIG_SMC)		+= smc/
+obj-$(CONFIG_SMC_BPF)	+= smc/bpf_smc.o
 obj-$(CONFIG_RFKILL)		+= rfkill/
 obj-$(CONFIG_NET_9P)		+= 9p/
 obj-$(CONFIG_CAIF)		+= caif/
diff --git a/net/smc/Kconfig b/net/smc/Kconfig
index 1ab3c5a..0a584bb 100644
--- a/net/smc/Kconfig
+++ b/net/smc/Kconfig
@@ -19,3 +19,16 @@ config SMC_DIAG
 	  smcss.
 
 	  if unsure, say Y.
+
+if SMC
+config SMC_BPF
+	bool "SMC: support eBPF" if SMC
+	depends on BPF_SYSCALL
+	default n
+	help
+	  Supports eBPF to allows user mode participation in SMC's protocol process
+	  via ebpf programs. Alternatively, obtain information about the SMC socks
+	  through the ebpf program.
+
+	  If unsure, say N.
+endif
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index a4cccdf..567feef 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -68,6 +68,49 @@
 static void smc_tcp_listen_work(struct work_struct *);
 static void smc_connect_work(struct work_struct *);
 
+static int smc_sock_should_select_smc(const struct smc_sock *smc)
+{
+#ifdef CONFIG_SMC_BPF
+	const struct smc_sock_negotiator_ops *ops;
+	int ret;
+
+	rcu_read_lock();
+	ops = READ_ONCE(smc->negotiator_ops);
+
+	/* No negotiator_ops supply or no negotiate func set,
+	 * always pass it.
+	 */
+	if (!ops || !ops->negotiate) {
+		rcu_read_unlock();
+		return SK_PASS;
+	}
+
+	ret = ops->negotiate((struct sock *)&smc->sk);
+	rcu_read_unlock();
+	return ret;
+#else
+	return SK_PASS;
+#endif
+}
+
+#ifdef CONFIG_SMC_BPF
+static void smc_sock_perform_collecting_info(const struct smc_sock *smc, int timing)
+{
+	const struct smc_sock_negotiator_ops *ops;
+
+	rcu_read_lock();
+	ops = READ_ONCE(smc->negotiator_ops);
+
+	if (!ops || !ops->collect_info) {
+		rcu_read_unlock();
+		return;
+	}
+
+	ops->collect_info((struct sock *)&smc->sk, timing);
+	rcu_read_unlock();
+}
+#endif
+
 int smc_nl_dump_hs_limitation(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	struct smc_nl_dmp_ctx *cb_ctx = smc_nl_dmp_ctx(cb);
@@ -166,6 +209,9 @@ static bool smc_hs_congested(const struct sock *sk)
 	if (workqueue_congested(WORK_CPU_UNBOUND, smc_hs_wq))
 		return true;
 
+	if (!smc_sock_should_select_smc(smc))
+		return true;
+
 	return false;
 }
 
@@ -320,6 +366,11 @@ static int smc_release(struct socket *sock)
 	sock_hold(sk); /* sock_put below */
 	smc = smc_sk(sk);
 
+#ifdef CONFIG_SMC_BPF
+	/* trigger info gathering if needed.*/
+	smc_sock_perform_collecting_info(smc, SMC_SOCK_CLOSED_TIMING);
+#endif
+
 	old_state = sk->sk_state;
 
 	/* cleanup for a dangling non-blocking connect */
@@ -360,6 +411,10 @@ static void smc_destruct(struct sock *sk)
 		return;
 	if (!sock_flag(sk, SOCK_DEAD))
 		return;
+#ifdef CONFIG_SMC_BPF
+	/* cleanup negotiator_ops if set */
+	smc_sock_cleanup_negotiator_ops(smc_sk(sk), /* in release */ 1);
+#endif
 }
 
 static struct sock *smc_sock_alloc(struct net *net, struct socket *sock,
@@ -1627,7 +1682,14 @@ static int smc_connect(struct socket *sock, struct sockaddr *addr,
 	}
 
 	smc_copy_sock_settings_to_clc(smc);
-	tcp_sk(smc->clcsock->sk)->syn_smc = 1;
+	/* accept out connection as SMC connection */
+	if (smc_sock_should_select_smc(smc) == SK_PASS) {
+		tcp_sk(smc->clcsock->sk)->syn_smc = 1;
+	} else {
+		tcp_sk(smc->clcsock->sk)->syn_smc = 0;
+		smc_switch_to_fallback(smc, /* active fallback */ 0);
+	}
+
 	if (smc->connect_nonblock) {
 		rc = -EALREADY;
 		goto out;
@@ -1679,6 +1741,10 @@ static int smc_clcsock_accept(struct smc_sock *lsmc, struct smc_sock **new_smc)
 	}
 	*new_smc = smc_sk(new_sk);
 
+#ifdef CONFIG_SMC_BPF
+	smc_sock_clone_negotiator_ops(lsk, new_sk);
+#endif
+
 	mutex_lock(&lsmc->clcsock_release_lock);
 	if (lsmc->clcsock)
 		rc = kernel_accept(lsmc->clcsock, &new_clcsock, SOCK_NONBLOCK);
diff --git a/net/smc/bpf_smc.c b/net/smc/bpf_smc.c
new file mode 100644
index 0000000..e41c238
--- /dev/null
+++ b/net/smc/bpf_smc.c
@@ -0,0 +1,200 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  Support eBPF for Shared Memory Communications over RDMA (SMC-R) and RoCE
+ *
+ *  Copyright IBM Corp. 2016, 2018
+ *
+ *  Author(s):  D. Wythe <alibuda@linux.alibaba.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/bpf.h>
+#include <linux/smc.h>
+#include <net/sock.h>
+#include "smc.h"
+
+static DEFINE_SPINLOCK(smc_sock_negotiator_list_lock);
+static LIST_HEAD(smc_sock_negotiator_list);
+
+/* required smc_sock_negotiator_list_lock locked */
+static struct smc_sock_negotiator_ops *smc_negotiator_ops_get_by_key(u32 key)
+{
+	struct smc_sock_negotiator_ops *ops;
+
+	list_for_each_entry_rcu(ops, &smc_sock_negotiator_list, list) {
+		if (ops->key == key)
+			return ops;
+	}
+
+	return NULL;
+}
+
+/* required smc_sock_negotiator_list_lock locked */
+struct smc_sock_negotiator_ops *smc_negotiator_ops_get_by_name(const char *name)
+{
+	struct smc_sock_negotiator_ops *ops;
+
+	list_for_each_entry_rcu(ops, &smc_sock_negotiator_list, list) {
+		if (strcmp(ops->name, name) == 0)
+			return ops;
+	}
+
+	return NULL;
+}
+
+static int smc_sock_validate_negotiator_ops(struct smc_sock_negotiator_ops *ops)
+{
+	/* not required yet */
+	return 0;
+}
+
+/* register ops */
+int smc_sock_register_negotiator_ops(struct smc_sock_negotiator_ops *ops)
+{
+	int ret;
+
+	ret = smc_sock_validate_negotiator_ops(ops);
+	if (ret)
+		return ret;
+
+	/* calt key by name hash */
+	ops->key = jhash(ops->name, sizeof(ops->name), strlen(ops->name));
+
+	spin_lock(&smc_sock_negotiator_list_lock);
+	if (smc_negotiator_ops_get_by_key(ops->key)) {
+		pr_notice("smc: %s negotiator already registered\n", ops->name);
+		ret = -EEXIST;
+	} else {
+		list_add_tail_rcu(&ops->list, &smc_sock_negotiator_list);
+	}
+	spin_unlock(&smc_sock_negotiator_list_lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(smc_sock_register_negotiator_ops);
+
+/* unregister ops */
+void smc_sock_unregister_negotiator_ops(struct smc_sock_negotiator_ops *ops)
+{
+	spin_lock(&smc_sock_negotiator_list_lock);
+	list_del_rcu(&ops->list);
+	spin_unlock(&smc_sock_negotiator_list_lock);
+
+	/* Wait for outstanding readers to complete before the
+	 * ops gets removed entirely.
+	 */
+	synchronize_rcu();
+}
+EXPORT_SYMBOL_GPL(smc_sock_unregister_negotiator_ops);
+
+int smc_sock_update_negotiator_ops(struct smc_sock_negotiator_ops *ops,
+				   struct smc_sock_negotiator_ops *old_ops)
+{
+	struct smc_sock_negotiator_ops *existing;
+	int ret;
+
+	ret = smc_sock_validate_negotiator_ops(ops);
+	if (ret)
+		return ret;
+
+	ops->key = jhash(ops->name, sizeof(ops->name), strlen(ops->name));
+	if (unlikely(!ops->key))
+		return -EINVAL;
+
+	spin_lock(&smc_sock_negotiator_list_lock);
+	existing = smc_negotiator_ops_get_by_key(old_ops->key);
+	if (!existing || strcmp(existing->name, ops->name)) {
+		ret = -EINVAL;
+	} else if (existing != old_ops) {
+		pr_notice("invalid old negotiator to replace\n");
+		ret = -EINVAL;
+	} else {
+		list_add_tail_rcu(&ops->list, &smc_sock_negotiator_list);
+		list_del_rcu(&existing->list);
+	}
+
+	spin_unlock(&smc_sock_negotiator_list_lock);
+	if (ret)
+		return ret;
+
+	synchronize_rcu();
+	return 0;
+}
+EXPORT_SYMBOL_GPL(smc_sock_update_negotiator_ops);
+
+/* assign ops to sock */
+int smc_sock_assign_negotiator_ops(struct smc_sock *smc, const char *name)
+{
+	struct smc_sock_negotiator_ops *ops;
+	int ret = -EINVAL;
+
+	/* already set */
+	if (READ_ONCE(smc->negotiator_ops))
+		smc_sock_cleanup_negotiator_ops(smc, /* in release */ 0);
+
+	/* Just for clear negotiator_ops */
+	if (!name || !strlen(name))
+		return 0;
+
+	rcu_read_lock();
+	ops = smc_negotiator_ops_get_by_name(name);
+	if (likely(ops)) {
+		if (unlikely(!bpf_try_module_get(ops, ops->owner))) {
+			ret = -EACCES;
+		} else {
+			WRITE_ONCE(smc->negotiator_ops, ops);
+			/* make sure ops can be seen */
+			smp_wmb();
+			if (ops->init)
+				ops->init(&smc->sk);
+			ret = 0;
+		}
+	}
+	rcu_read_unlock();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(smc_sock_assign_negotiator_ops);
+
+/* reset ops to sock */
+void smc_sock_cleanup_negotiator_ops(struct smc_sock *smc, int in_release)
+{
+	const struct smc_sock_negotiator_ops *ops;
+
+	ops = READ_ONCE(smc->negotiator_ops);
+
+	/* not all smc sock has negotiator_ops */
+	if (!ops)
+		return;
+
+	might_sleep();
+
+	/* Just ensure data integrity */
+	WRITE_ONCE(smc->negotiator_ops, NULL);
+	/* make sure NULL can be seen */
+	smp_wmb();
+	/* If the cleanup was not caused by the release of the sock,
+	 * it means that we may need to wait for the readers of ops
+	 * to complete.
+	 */
+	if (unlikely(!in_release))
+		synchronize_rcu();
+	if (ops->release)
+		ops->release(&smc->sk);
+	bpf_module_put(ops, ops->owner);
+}
+EXPORT_SYMBOL_GPL(smc_sock_cleanup_negotiator_ops);
+
+void smc_sock_clone_negotiator_ops(struct sock *parent, struct sock *child)
+{
+	const struct smc_sock_negotiator_ops *ops;
+
+	rcu_read_lock();
+	ops = READ_ONCE(smc_sk(parent)->negotiator_ops);
+	if (ops && bpf_try_module_get(ops, ops->owner)) {
+		smc_sk(child)->negotiator_ops = ops;
+		if (ops->init)
+			ops->init(child);
+	}
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(smc_sock_clone_negotiator_ops);
+
-- 
1.8.3.1

[RFC PATCH bpf-next 3/5] net/smc: allow set or get smc negotiator by sockopt

[D. Wythe]

From: "D. Wythe" <alibuda@linux.alibaba.com>

Allow applications to set specific protocol negotiation rules for SMC
Socks. Typically, applications need to know the name of the negotiator
and then set it through the syscall setsockopt, for examples:

const char name[] = "apps";
setsockopt(fd, SOL_SMC, SMC_NEGOTIATOR, name, sizeof(name) - 1);

Noted that there is no default negotiator in SMC implementation,
the application needs to inject the specific implementation through
eBPF before setting it up. Although no default negotiator implementation
is provided,

Note that SMC does not provide a default negotiator in SMC
implementation,
and the application needs to inject the specific implementation through
eBPF before setting it up. Although no default negotiator implementation
is provided, logically it can be seen as an implementation that
always return SK_PASS.

Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
---
 include/uapi/linux/smc.h |   1 +
 net/smc/af_smc.c         | 135 +++++++++++++++++++++++++++++++++++------------
 2 files changed, 102 insertions(+), 34 deletions(-)

diff --git a/include/uapi/linux/smc.h b/include/uapi/linux/smc.h
index bb4dacc..1887ed5 100644
--- a/include/uapi/linux/smc.h
+++ b/include/uapi/linux/smc.h
@@ -299,5 +299,6 @@ enum {
 
 /* SMC socket options */
 #define SMC_LIMIT_HS 1	/* constraint on smc handshake */
+#define SMC_NEGOTIATOR 2 /* SMC protocol negotiator */
 
 #endif /* _UAPI_LINUX_SMC_H */
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index 567feef..05e5aaf 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -2932,48 +2932,41 @@ static int smc_shutdown(struct socket *sock, int how)
 	return rc ? rc : rc1;
 }
 
-static int __smc_getsockopt(struct socket *sock, int level, int optname,
-			    char __user *optval, int __user *optlen)
+/* set smc negotoiatior by name */
+static int smc_setsockopt_negotiator(struct sock *sk, sockptr_t optval,
+				     unsigned int optlen)
 {
-	struct smc_sock *smc;
-	int val, len;
-
-	smc = smc_sk(sock->sk);
-
-	if (get_user(len, optlen))
-		return -EFAULT;
-
-	len = min_t(int, len, sizeof(int));
+#ifdef CONFIG_SMC_BPF
+	char name[SMC_NEGOTIATOR_NAME_MAX];
+	struct smc_sock *smc = smc_sk(sk);
+	int val, rc;
 
-	if (len < 0)
+	if (optlen < 1)
 		return -EINVAL;
 
-	switch (optname) {
-	case SMC_LIMIT_HS:
-		val = smc->limit_smc_hs;
-		break;
-	default:
-		return -EOPNOTSUPP;
-	}
-
-	if (put_user(len, optlen))
-		return -EFAULT;
-	if (copy_to_user(optval, &val, len))
+	val = strncpy_from_sockptr(name, optval,
+				   min_t(long, SMC_NEGOTIATOR_NAME_MAX - 1, optlen));
+	if (val < 0)
 		return -EFAULT;
 
-	return 0;
+	/* typical c str */
+	name[val] = 0;
+
+	sockopt_lock_sock(sk);
+	rc = smc_sock_assign_negotiator_ops(smc, name);
+	sockopt_release_sock(sk);
+	return rc;
+#else
+	return -EOPNOTSUPP;
+#endif
 }
 
-static int __smc_setsockopt(struct socket *sock, int level, int optname,
+static int __smc_setsockopt(struct sock *sk, int level, int optname,
 			    sockptr_t optval, unsigned int optlen)
 {
-	struct sock *sk = sock->sk;
-	struct smc_sock *smc;
+	struct smc_sock *smc = smc_sk(sk);
 	int val, rc;
 
-	smc = smc_sk(sk);
-
-	lock_sock(sk);
 	switch (optname) {
 	case SMC_LIMIT_HS:
 		if (optlen < sizeof(int)) {
@@ -2984,15 +2977,17 @@ static int __smc_setsockopt(struct socket *sock, int level, int optname,
 			rc = -EFAULT;
 			break;
 		}
-
+		sockopt_lock_sock(sk);
 		smc->limit_smc_hs = !!val;
+		sockopt_release_sock(sk);
 		rc = 0;
 		break;
+	case SMC_NEGOTIATOR:
+		return smc_setsockopt_negotiator(sk, optval, optlen);
 	default:
 		rc = -EOPNOTSUPP;
 		break;
 	}
-	release_sock(sk);
 
 	return rc;
 }
@@ -3007,7 +3002,7 @@ static int smc_setsockopt(struct socket *sock, int level, int optname,
 	if (level == SOL_TCP && optname == TCP_ULP)
 		return -EOPNOTSUPP;
 	else if (level == SOL_SMC)
-		return __smc_setsockopt(sock, level, optname, optval, optlen);
+		return __smc_setsockopt(sk, level, optname, optval, optlen);
 
 	smc = smc_sk(sk);
 
@@ -3084,6 +3079,77 @@ static int smc_setsockopt(struct socket *sock, int level, int optname,
 	return rc;
 }
 
+/* get current negotoiatior sock used */
+static int smc_getsockopt_negotiator(struct sock *sk, sockptr_t optval,
+				     sockptr_t optlen)
+{
+#ifdef CONFIG_SMC_BPF
+	const struct smc_sock_negotiator_ops *ops;
+	struct smc_sock *smc = smc_sk(sk);
+	int len;
+
+	if (copy_from_sockptr(&len, optlen, sizeof(int)))
+		return -EFAULT;
+
+	len = min_t(unsigned int, len, sizeof(int));
+
+	if (len < 0)
+		return -EINVAL;
+
+	rcu_read_lock();
+	ops = READ_ONCE(smc->negotiator_ops);
+	if (ops) {
+		len = min_t(unsigned int, len, SMC_NEGOTIATOR_NAME_MAX);
+		if (copy_to_sockptr(optval, ops->name, len)) {
+			rcu_read_unlock();
+			return -EFAULT;
+		}
+	} else {
+		len = 0;
+	}
+	rcu_read_unlock();
+
+	if (copy_to_sockptr(optlen, &len, sizeof(int)))
+		return -EFAULT;
+
+	return 0;
+#else
+	return -EOPNOTSUPP;
+#endif
+}
+
+static int __smc_getsockopt(struct sock *sk, int level, int optname,
+			    sockptr_t optval, sockptr_t optlen)
+{
+	struct smc_sock *smc = smc_sk(sk);
+	int val, len;
+
+	if (copy_from_sockptr(&len, optlen, sizeof(int)))
+		return -EFAULT;
+
+	len = min_t(unsigned int, len, sizeof(int));
+
+	if (len < 0)
+		return -EINVAL;
+
+	switch (optname) {
+	case SMC_LIMIT_HS:
+		val = smc->limit_smc_hs;
+		break;
+	case SMC_NEGOTIATOR:
+		return smc_getsockopt_negotiator(sk, optval, optlen);
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	if (copy_to_sockptr(optval, &val, len))
+		return -EFAULT;
+	if (copy_to_sockptr(optlen, &len, sizeof(int)))
+		return -EFAULT;
+
+	return 0;
+}
+
 static int smc_getsockopt(struct socket *sock, int level, int optname,
 			  char __user *optval, int __user *optlen)
 {
@@ -3091,7 +3157,8 @@ static int smc_getsockopt(struct socket *sock, int level, int optname,
 	int rc;
 
 	if (level == SOL_SMC)
-		return __smc_getsockopt(sock, level, optname, optval, optlen);
+		return __smc_getsockopt(sock->sk, level, optname,
+					USER_SOCKPTR(optval), USER_SOCKPTR(optlen));
 
 	smc = smc_sk(sock->sk);
 	mutex_lock(&smc->clcsock_release_lock);
-- 
1.8.3.1

[RFC PATCH bpf-next 4/5] bpf: add smc negotiator support in BPF struct_ops

[D. Wythe]

From: "D. Wythe" <alibuda@linux.alibaba.com>

This PATCH attempts to introduce BPF injection capability for SMC.
Considering that the SMC protocol is not suitable for all scenarios,
especially for short-lived. However, for most applications, they cannot
guarantee that there are no such scenarios at all. Therefore, apps
may need some specific strategies to decide shall we need to use SMC
or not, for example, apps can limit the scope of the SMC to a specific
IP address or port.

Based on the consideration of transparent replacement, we hope that apps
can remain transparent even if they need to formulate some specific
strategies for SMC using. That is, do not need to recompile their code.

On the other hand, we need to ensure the scalability of strategies
implementation. Although it is simple to use socket options or sysctl,
it will bring more complexity to subsequent expansion.

Fortunately, BPF can solve these concerns very well, users can write
thire own strategies in eBPF to choose whether to use SMC or not.
And it's quite easy for them to modify their strategies in the future.

This PATCH implement injection capability for SMC via struct_ops.
In that way, we can add new injection scenarios in the future.

Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
---
 kernel/bpf/bpf_struct_ops_types.h |   4 +
 net/smc/bpf_smc.c                 | 159 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 163 insertions(+)

diff --git a/kernel/bpf/bpf_struct_ops_types.h b/kernel/bpf/bpf_struct_ops_types.h
index 5678a9d..35cdd15 100644
--- a/kernel/bpf/bpf_struct_ops_types.h
+++ b/kernel/bpf/bpf_struct_ops_types.h
@@ -9,4 +9,8 @@
 #include <net/tcp.h>
 BPF_STRUCT_OPS_TYPE(tcp_congestion_ops)
 #endif
+#if IS_ENABLED(CONFIG_SMC)
+#include <net/smc.h>
+BPF_STRUCT_OPS_TYPE(smc_sock_negotiator_ops)
+#endif
 #endif
diff --git a/net/smc/bpf_smc.c b/net/smc/bpf_smc.c
index e41c238..c245862 100644
--- a/net/smc/bpf_smc.c
+++ b/net/smc/bpf_smc.c
@@ -7,14 +7,20 @@
  *  Author(s):  D. Wythe <alibuda@linux.alibaba.com>
  */
 
+#include <linux/bpf_verifier.h>
+#include <linux/btf_ids.h>
 #include <linux/kernel.h>
 #include <linux/bpf.h>
+#include <linux/btf.h>
 #include <linux/smc.h>
 #include <net/sock.h>
 #include "smc.h"
 
+struct bpf_struct_ops bpf_smc_sock_negotiator_ops;
+
 static DEFINE_SPINLOCK(smc_sock_negotiator_list_lock);
 static LIST_HEAD(smc_sock_negotiator_list);
+static u32 smc_sock_id, sock_id;
 
 /* required smc_sock_negotiator_list_lock locked */
 static struct smc_sock_negotiator_ops *smc_negotiator_ops_get_by_key(u32 key)
@@ -198,3 +204,156 @@ void smc_sock_clone_negotiator_ops(struct sock *parent, struct sock *child)
 }
 EXPORT_SYMBOL_GPL(smc_sock_clone_negotiator_ops);
 
+static int bpf_smc_negotiator_init(struct btf *btf)
+{
+	s32 type_id;
+
+	type_id = btf_find_by_name_kind(btf, "sock", BTF_KIND_STRUCT);
+	if (type_id < 0)
+		return -EINVAL;
+	sock_id = type_id;
+
+	type_id = btf_find_by_name_kind(btf, "smc_sock", BTF_KIND_STRUCT);
+	if (type_id < 0)
+		return -EINVAL;
+	smc_sock_id = type_id;
+
+	return 0;
+}
+
+/* register ops */
+static int bpf_smc_negotiator_reg(void *kdata)
+{
+	return smc_sock_register_negotiator_ops(kdata);
+}
+
+/* unregister ops */
+static void bpf_smc_negotiator_unreg(void *kdata)
+{
+	smc_sock_unregister_negotiator_ops(kdata);
+}
+
+/* unregister ops */
+static int bpf_smc_negotiator_update(void *kdata, void *old_kdata)
+{
+	return smc_sock_update_negotiator_ops(kdata, old_kdata);
+}
+
+static int bpf_smc_negotiator_validate(void *kdata)
+{
+	return smc_sock_validate_negotiator_ops(kdata);
+}
+
+static int bpf_smc_negotiator_check_member(const struct btf_type *t,
+					   const struct btf_member *member,
+					   const struct bpf_prog *prog)
+{
+	return 0;
+}
+
+static int bpf_smc_negotiator_init_member(const struct btf_type *t,
+					  const struct btf_member *member,
+					  void *kdata, const void *udata)
+{
+	const struct smc_sock_negotiator_ops *uops;
+	struct smc_sock_negotiator_ops *ops;
+	u32 moff;
+
+	uops = (const struct smc_sock_negotiator_ops *)udata;
+	ops = (struct smc_sock_negotiator_ops *)kdata;
+
+	moff = __btf_member_bit_offset(t, member) / 8;
+
+	/* init name */
+	if (moff ==  offsetof(struct smc_sock_negotiator_ops, name)) {
+		if (bpf_obj_name_cpy(ops->name, uops->name,
+				     sizeof(uops->name)) <= 0)
+			return -EINVAL;
+		return 1;
+	}
+
+	return 0;
+}
+
+BPF_CALL_1(bpf_smc_skc_to_tcp_sock, struct sock *, sk)
+{
+	if (sk && sk_fullsock(sk) && sk->sk_family == AF_SMC)
+		return (unsigned long)((struct smc_sock *)(sk))->clcsock->sk;
+
+	return (unsigned long)NULL;
+}
+
+const struct bpf_func_proto bpf_smc_skc_to_tcp_sock_proto = {
+	.func			= bpf_smc_skc_to_tcp_sock,
+	.gpl_only		= false,
+	.ret_type		= RET_PTR_TO_BTF_ID_OR_NULL,
+	.arg1_type		= ARG_PTR_TO_BTF_ID_SOCK_COMMON,
+	.ret_btf_id		= &btf_sock_ids[BTF_SOCK_TYPE_TCP],
+};
+
+static const struct bpf_func_proto *
+smc_negotiator_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
+{
+	const struct btf_member *m;
+	const struct btf_type *t;
+	u32 midx, moff;
+
+	midx = prog->expected_attach_type;
+	t = bpf_smc_sock_negotiator_ops.type;
+	m = &btf_type_member(t)[midx];
+
+	moff = __btf_member_bit_offset(t, m) / 8;
+
+	switch (func_id) {
+	case BPF_FUNC_setsockopt:
+		switch (moff) {
+		/* Avoid potential deadloop risk */
+		case offsetof(struct smc_sock_negotiator_ops, init):
+			fallthrough;
+		/* Avoid potential leak risk */
+		case offsetof(struct smc_sock_negotiator_ops, release):
+			return NULL;
+		}
+		return &bpf_sk_setsockopt_proto;
+	case BPF_FUNC_getsockopt:
+		return &bpf_sk_getsockopt_proto;
+	case BPF_FUNC_skc_to_tcp_sock:
+		return &bpf_smc_skc_to_tcp_sock_proto;
+	default:
+		return bpf_base_func_proto(func_id);
+	}
+}
+
+static bool smc_negotiator_prog_is_valid_access(int off, int size, enum bpf_access_type type,
+						const struct bpf_prog *prog,
+						struct bpf_insn_access_aux *info)
+{
+	if (!bpf_tracing_btf_ctx_access(off, size, type, prog, info))
+		return false;
+
+	/* promote it to smc_sock */
+	if (base_type(info->reg_type) == PTR_TO_BTF_ID &&
+	    !bpf_type_has_unsafe_modifiers(info->reg_type) &&
+	    info->btf_id == sock_id)
+		info->btf_id = smc_sock_id;
+
+	return true;
+}
+
+static const struct bpf_verifier_ops bpf_smc_negotiator_verifier_ops = {
+	.get_func_proto  = smc_negotiator_prog_func_proto,
+	.is_valid_access = smc_negotiator_prog_is_valid_access,
+};
+
+struct bpf_struct_ops bpf_smc_sock_negotiator_ops = {
+	.verifier_ops = &bpf_smc_negotiator_verifier_ops,
+	.init = bpf_smc_negotiator_init,
+	.check_member = bpf_smc_negotiator_check_member,
+	.init_member = bpf_smc_negotiator_init_member,
+	.reg = bpf_smc_negotiator_reg,
+	.update = bpf_smc_negotiator_update,
+	.unreg = bpf_smc_negotiator_unreg,
+	.validate = bpf_smc_negotiator_validate,
+	.name = "smc_sock_negotiator_ops",
+};
+
-- 
1.8.3.1

[RFC PATCH bpf-next 5/5] bpf/selftests: add selftest for SMC bpf capability

[D. Wythe]

From: "D. Wythe" <alibuda@linux.alibaba.com>

This PATCH adds a tiny selftest for SMC bpf capability,
making decisions on whether to use SMC by collecting
certain information from kernel smc sock.

Follow the steps below to run this test.

make -C tools/testing/selftests/bpf
cd tools/testing/selftests/bpf
sudo ./test_progs -t smc

Results shows:
18/1    bpf_smc/load:OK
18/2    bpf_smc/update:OK
18/3    bpf_smc/ref:OK
18      bpf_smc:OK
Summary: 1/3 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
---
 tools/testing/selftests/bpf/prog_tests/bpf_smc.c | 107 +++++++++
 tools/testing/selftests/bpf/progs/bpf_smc.c      | 265 +++++++++++++++++++++++
 2 files changed, 372 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_smc.c
 create mode 100644 tools/testing/selftests/bpf/progs/bpf_smc.c

diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_smc.c b/tools/testing/selftests/bpf/prog_tests/bpf_smc.c
new file mode 100644
index 0000000..e668857
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_smc.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/err.h>
+#include <netinet/tcp.h>
+#include <test_progs.h>
+#include "network_helpers.h"
+#include "bpf_smc.skel.h"
+
+#define SOL_SMC 286
+#define SMC_NEGOTIATOR 2
+static const char name[] = "apps";
+
+void run_smc(void)
+{
+	int fd, err;
+
+	fd = socket(AF_SMC, SOCK_STREAM, 0);
+	ASSERT_GT(fd, 0, "create smc socket");
+
+	err = setsockopt(fd, SOL_SMC, SMC_NEGOTIATOR, name, sizeof(name) / sizeof(char));
+	ASSERT_EQ(err, 0, "setsockopt");
+
+	close(fd);
+}
+
+void test_load(void)
+{
+	struct bpf_smc *smc_skel;
+	struct bpf_link *link;
+
+	smc_skel = bpf_smc__open_and_load();
+	if (!ASSERT_OK_PTR(smc_skel, "skel_open"))
+		return;
+
+	link = bpf_map__attach_struct_ops(smc_skel->maps.ops);
+	if (!ASSERT_OK_PTR(link, "bpf_map__attach_struct_ops"))
+		goto error;
+
+	bpf_link__destroy(link);
+error:
+	bpf_smc__destroy(smc_skel);
+}
+
+void test_update(void)
+{
+	struct bpf_smc *smc_skel;
+	struct bpf_link *link;
+	int err;
+
+	smc_skel = bpf_smc__open_and_load();
+	if (!ASSERT_OK_PTR(smc_skel, "skel_open"))
+		return;
+
+	link = bpf_map__attach_struct_ops(smc_skel->maps.accept);
+	if (!ASSERT_OK_PTR(link, "bpf_map__attach_struct_ops"))
+		goto error;
+
+	run_smc();
+	ASSERT_EQ(smc_skel->bss->accept_cnt, 1, "accept_cnt");
+
+	err = bpf_link__update_map(link, smc_skel->maps.drop);
+	ASSERT_OK(err, "update_map");
+
+	run_smc();
+	ASSERT_EQ(smc_skel->bss->accept_cnt, 1, "accept_cnt");
+	ASSERT_EQ(smc_skel->bss->drop_cnt, 1, "drop_cnt");
+
+	bpf_link__destroy(link);
+error:
+	bpf_smc__destroy(smc_skel);
+}
+
+void test_ref(void)
+{
+	struct bpf_smc *smc_skel;
+	struct bpf_link *link;
+	int fd = 0, err;
+
+	smc_skel = bpf_smc__open_and_load();
+	if (!ASSERT_OK_PTR(smc_skel, "skel_open"))
+		return;
+
+	link = bpf_map__attach_struct_ops(smc_skel->maps.accept);
+	if (!ASSERT_OK_PTR(link, "bpf_map__attach_struct_ops"))
+		goto error;
+
+	fd = socket(AF_SMC, SOCK_STREAM, 0);
+	ASSERT_GT(fd, 0, "create smc socket");
+	err = setsockopt(fd, SOL_SMC, SMC_NEGOTIATOR, name, sizeof(name) / sizeof(char));
+	ASSERT_EQ(err, 0, "setsockopt");
+	bpf_link__destroy(link);
+	if (fd > 0)
+		close(fd);
+	ASSERT_EQ(smc_skel->bss->accept_release_cnt, 1, "accept_release_cnt");
+error:
+	bpf_smc__destroy(smc_skel);
+}
+
+void test_bpf_smc(void)
+{
+	if (test__start_subtest("load"))
+		test_load();
+	if (test__start_subtest("update"))
+		test_update();
+	if (test__start_subtest("ref"))
+		test_ref();
+}
diff --git a/tools/testing/selftests/bpf/progs/bpf_smc.c b/tools/testing/selftests/bpf/progs/bpf_smc.c
new file mode 100644
index 0000000..8ff70af
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/bpf_smc.c
@@ -0,0 +1,265 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_core_read.h>
+#include <bpf/bpf_tracing.h>
+
+#define AF_SMC			(43)
+#define SMC_LISTEN		(10)
+#define SMC_SOCK_CLOSED_TIMING	(0)
+extern unsigned long CONFIG_HZ __kconfig;
+#define HZ CONFIG_HZ
+
+char _license[] SEC("license") = "GPL";
+#define max(a, b) ((a) > (b) ? (a) : (b))
+
+static __always_inline struct smc_sock *smc_sk(struct sock *sk)
+{
+	return (struct smc_sock *)sk;
+}
+
+struct smc_prediction {
+	/* protection for smc_prediction */
+	struct bpf_spin_lock lock;
+	/* start of time slice */
+	__u64	start_tstamp;
+	/* delta of pacing */
+	__u64	pacing_delta;
+	/* N of closed connections determined as long connections
+	 * in current time slice
+	 */
+	__u32	closed_long_cc;
+	/* N of closed connections in this time slice */
+	__u32	closed_total_cc;
+	/* N of incoming connections determined as long connections
+	 * in current time slice
+	 */
+	__u32	incoming_long_cc;
+	/* last splice rate of long cc */
+	__u32	last_rate_of_lcc;
+};
+
+#define SMC_PREDICTION_MIN_PACING_DELTA                (1llu)
+#define SMC_PREDICTION_MAX_PACING_DELTA                (HZ << 3)
+#define SMC_PREDICTION_MAX_LONGCC_PER_SPLICE           (8)
+#define SMC_PREDICTION_MAX_PORT                        (64)
+#define SMC_PREDICTION_MAX_SPLICE_GAP                  (1)
+#define SMC_PREDICTION_LONGCC_RATE_THRESHOLD           (13189)
+#define SMC_PREDICTION_LONGCC_PACKETS_THRESHOLD        (100)
+#define SMC_PREDICTION_LONGCC_BYTES_THRESHOLD	\
+		(SMC_PREDICTION_LONGCC_PACKETS_THRESHOLD * 1024)
+
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__uint(max_entries, SMC_PREDICTION_MAX_PORT);
+	__type(key, __u16);
+	__type(value, struct smc_prediction);
+} negotiator_map SEC(".maps");
+
+
+static inline __u32 smc_prediction_calt_rate(struct smc_prediction *smc_predictor)
+{
+	if (!smc_predictor->closed_total_cc)
+		return smc_predictor->last_rate_of_lcc;
+
+	return (smc_predictor->closed_long_cc << 14) / smc_predictor->closed_total_cc;
+}
+
+static inline struct smc_prediction *smc_prediction_get(__u16 key, __u64 tstamp)
+{
+	struct smc_prediction zero = {}, *smc_predictor;
+	__u32 gap;
+	int err;
+
+	smc_predictor = bpf_map_lookup_elem(&negotiator_map, &key);
+	if (!smc_predictor) {
+		zero.start_tstamp = bpf_jiffies64();
+		zero.pacing_delta = SMC_PREDICTION_MIN_PACING_DELTA;
+		err = bpf_map_update_elem(&negotiator_map, &key, &zero, 0);
+		if (err)
+			return NULL;
+		smc_predictor =  bpf_map_lookup_elem(&negotiator_map, &key);
+		if (!smc_predictor)
+			return NULL;
+	}
+
+	if (tstamp) {
+		bpf_spin_lock(&smc_predictor->lock);
+		gap = (tstamp - smc_predictor->start_tstamp) / smc_predictor->pacing_delta;
+		/* new splice */
+		if (gap > 0) {
+			smc_predictor->start_tstamp = tstamp;
+			smc_predictor->last_rate_of_lcc =
+				(smc_prediction_calt_rate(smc_predictor) * 7) >> (2 + gap);
+			smc_predictor->closed_long_cc = 0;
+			smc_predictor->closed_total_cc = 0;
+			smc_predictor->incoming_long_cc = 0;
+		}
+		bpf_spin_unlock(&smc_predictor->lock);
+	}
+	return smc_predictor;
+}
+
+int SEC("struct_ops/bpf_smc_negotiate")
+BPF_PROG(bpf_smc_negotiate, struct sock *sk)
+{
+	struct smc_prediction *smc_predictor;
+	struct smc_sock *smc = smc_sk(sk);
+	struct tcp_sock *tp;
+	__u32 rate = 0;
+	__u16 key;
+
+	/* client side */
+	if (smc == NULL || smc->sk.__sk_common.skc_state != SMC_LISTEN) {
+		/* use Global smc_predictor */
+		key = 0;
+	} else {	/* server side */
+		tp = bpf_skc_to_tcp_sock(sk);
+		if (!tp)
+			goto error;
+		key = tp->inet_conn.icsk_inet.sk.__sk_common.skc_num;
+	}
+
+	smc_predictor = smc_prediction_get(key, bpf_jiffies64());
+	if (!smc_predictor)
+		return SK_PASS;
+
+	bpf_spin_lock(&smc_predictor->lock);
+
+	if (smc_predictor->incoming_long_cc == 0)
+		goto out_locked_pass;
+
+	if (smc_predictor->incoming_long_cc > SMC_PREDICTION_MAX_LONGCC_PER_SPLICE)
+		goto out_locked_drop;
+
+	rate = smc_prediction_calt_rate(smc_predictor);
+	if (rate < SMC_PREDICTION_LONGCC_RATE_THRESHOLD)
+		goto out_locked_drop;
+
+out_locked_pass:
+	smc_predictor->incoming_long_cc++;
+	bpf_spin_unlock(&smc_predictor->lock);
+	return SK_PASS;
+out_locked_drop:
+	bpf_spin_unlock(&smc_predictor->lock);
+error:
+	return SK_DROP;
+}
+
+void SEC("struct_ops/bpf_smc_collect_info")
+BPF_PROG(bpf_smc_collect_info, struct sock *sk, int timing)
+{
+	struct smc_prediction *smc_predictor;
+	int use_fallback, sndbuf;
+	struct smc_sock *smc;
+	struct tcp_sock *tp;
+	bool match = false;
+	__u16 wrap, count;
+	__u16 key;
+
+	/* no info can collect */
+	if (sk == NULL)
+		return;
+
+	/* only fouces on closed */
+	if (timing != SMC_SOCK_CLOSED_TIMING)
+		return;
+
+	/* every full smc sock should contains a tcp sock */
+	tp = bpf_skc_to_tcp_sock(sk);
+	if (!tp)
+		return;
+
+	smc = smc_sk(sk);
+	if (smc->use_fallback) {
+		use_fallback = 1;
+		match = tp->delivered > SMC_PREDICTION_LONGCC_PACKETS_THRESHOLD;
+	} else {
+		wrap = smc->conn.tx_curs_sent.wrap;
+		count = smc->conn.tx_curs_sent.count;
+		sndbuf = tp->inet_conn.icsk_inet.sk.sk_sndbuf;
+		match = (count + wrap * sndbuf) > SMC_PREDICTION_LONGCC_BYTES_THRESHOLD;
+	}
+
+	key = tp->inet_conn.icsk_inet.sk.__sk_common.skc_num;
+
+	smc_predictor = smc_prediction_get(key, 0);
+	if (!smc_predictor)
+		goto error;
+
+	bpf_spin_lock(&smc_predictor->lock);
+	smc_predictor->closed_total_cc++;
+	if (match) {
+		/* increase stats */
+		smc_predictor->closed_long_cc++;
+		/* try more aggressive */
+		if (smc_predictor->pacing_delta > SMC_PREDICTION_MIN_PACING_DELTA) {
+			if (use_fallback) {
+				smc_predictor->pacing_delta = max(SMC_PREDICTION_MIN_PACING_DELTA,
+						(smc_predictor->pacing_delta * 3) >> 2);
+			}
+		}
+	} else if (!use_fallback) {
+		smc_predictor->pacing_delta <<= 1;
+	}
+	bpf_spin_unlock(&smc_predictor->lock);
+error:
+	return;
+}
+
+SEC(".struct_ops.link")
+struct smc_sock_negotiator_ops ops = {
+	.name = "apps",
+	.negotiate	= (void *)bpf_smc_negotiate,
+	.collect_info	= (void *)bpf_smc_collect_info,
+};
+
+int accept_cnt = 0;
+int drop_cnt = 0;
+int accept_release_cnt = 0;
+
+int SEC("struct_ops/bpf_smc_accept")
+BPF_PROG(bpf_smc_accept, struct sock *sk)
+{
+	return SK_PASS;
+}
+
+void SEC("struct_ops/bpf_smc_accept_init")
+BPF_PROG(bpf_smc_accept_init, struct sock *sk)
+{
+	accept_cnt++;
+}
+
+void SEC("struct_ops/bpf_smc_accept_release")
+BPF_PROG(bpf_smc_accept_release, struct sock *sk)
+{
+	accept_release_cnt++;
+}
+
+int SEC("struct_ops/bpf_smc_drop")
+BPF_PROG(bpf_smc_drop, struct sock *sk)
+{
+	return SK_DROP;
+}
+
+void SEC("struct_ops/bpf_smc_drop_init")
+BPF_PROG(bpf_smc_drop_init, struct sock *sk)
+{
+	drop_cnt++;
+}
+
+SEC(".struct_ops.link")
+struct smc_sock_negotiator_ops accept = {
+	.name = "apps",
+	.init = (void *) bpf_smc_accept_init,
+	.release = (void *) bpf_smc_accept_release,
+	.negotiate = (void *) bpf_smc_accept,
+};
+
+SEC(".struct_ops.link")
+struct smc_sock_negotiator_ops drop = {
+	.name = "apps",
+	.init = (void *) bpf_smc_drop_init,
+	.negotiate = (void *) bpf_smc_drop,
+};
-- 
1.8.3.1

Re: [RFC PATCH bpf-next 0/5] net/smc: Introduce BPF injection capability

[D. Wythe]

Hi everyone,

It's seems the RFC patch been hanging for some time.  I would like to 
politely inquire if there are any suggestions or criticisms.
Compared to previous patches, this patch has several main features:

1. Allow registration of multiple negotiators, each SMC negotiator has a 
name and can be indexed that name
2. no read/write lock anymore
3. support bpf update

If you have any suggestions or criticisms, please let me know.

Thanks
D. Wythe

On 4/6/23 11:30 PM, D. Wythe wrote:
> From: "D. Wythe" <alibuda@linux.alibaba.com>
>
> This patches attempt to introduce BPF injection capability for SMC,
> and add selftest to ensure code stability.
>
> As we all know that the SMC protocol is not suitable for all scenarios,
> especially for short-lived. However, for most applications, they cannot
> guarantee that there are no such scenarios at all. Therefore, apps
> may need some specific strategies to decide shall we need to use SMC
> or not, for example, apps can limit the scope of the SMC to a specific
> IP address or port.
>
> Based on the consideration of transparent replacement, we hope that apps
> can remain transparent even if they need to formulate some specific
> strategies for SMC using. That is, do not need to recompile their code.
>
> On the other hand, we need to ensure the scalability of strategies
> implementation. Although it is simple to use socket options or sysctl,
> it will bring more complexity to subsequent expansion.
>
> Fortunately, BPF can solve these concerns very well, users can write
> thire own strategies in eBPF to choose whether to use SMC or not.
> And it's quite easy for them to modify their strategies in the future.
>
> This patches implement injection capability for SMC via struct_ops.
> In that way, we can add new injection scenarios in the future.
>
> D. Wythe (5):
>    net/smc: move smc_sock related structure definition
>    net/smc: net/smc: allow smc to negotiate protocols on policies
>    net/smc: allow set or get smc negotiator by sockopt
>    bpf: add smc negotiator support in BPF struct_ops
>    bpf/selftests: add selftest for SMC bpf capability
>
>   include/net/smc.h                                | 268 +++++++++++++++++
>   include/uapi/linux/smc.h                         |   1 +
>   kernel/bpf/bpf_struct_ops_types.h                |   4 +
>   net/Makefile                                     |   1 +
>   net/smc/Kconfig                                  |  13 +
>   net/smc/af_smc.c                                 | 203 ++++++++++---
>   net/smc/bpf_smc.c                                | 359 +++++++++++++++++++++++
>   net/smc/smc.h                                    | 224 --------------
>   tools/testing/selftests/bpf/prog_tests/bpf_smc.c | 107 +++++++
>   tools/testing/selftests/bpf/progs/bpf_smc.c      | 265 +++++++++++++++++
>   10 files changed, 1186 insertions(+), 259 deletions(-)
>   create mode 100644 net/smc/bpf_smc.c
>   create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_smc.c
>   create mode 100644 tools/testing/selftests/bpf/progs/bpf_smc.c
>