Merge branch 'skb_sk-sk_fullsock-tcp_sock'

Martin KaFai Lau says:

====================
This series adds __sk_buff->sk, "struct bpf_tcp_sock",
BPF_FUNC_sk_fullsock and BPF_FUNC_tcp_sock.  Together, they provide
a common way to expose the members of "struct tcp_sock" and
"struct bpf_sock" for the bpf_prog to access.

The patch series first adds a bpf_sock pointer to __sk_buff
and a new helper BPF_FUNC_sk_fullsock.

It then adds BPF_FUNC_tcp_sock to get a bpf_tcp_sock
pointer from a bpf_sock pointer.

The current use case is to allow a cg_skb_bpf_prog to provide
per cgroup traffic policing/shaping.

Please see individual patch for details.

v2:
- Patch 1 depends on
  commit d623876646be ("bpf: Fix narrow load on a bpf_sock returned from sk_lookup()")
  in the bpf branch.
- Add sk_to_full_sk() to bpf_sk_fullsock() and bpf_tcp_sock()
  such that there is a way to access the listener's sk and tcp_sk
  when __sk_buff->sk is a request_sock.
  The comments in the uapi bpf.h is updated accordingly.
- bpf_ctx_range_till() is used in bpf_sock_common_is_valid_access()
  in patch 1.  Saved a few lines.
- Patch 2 is new in v2 and it adds "state", "dst_ip4", "dst_ip6" and
  "dst_port" to the bpf_sock.  Narrow load is allowed on them.
  The "state" (i.e. sk_state) has already been used in
  INET_DIAG (e.g. ss -t) and getsockopt(TCP_INFO).
- While at it in the new patch 2, also allow narrow load on some
  existing fields of the bpf_sock, which are "family", "type", "protocol"
  and "src_port".  Only allow loading from first byte for now.
  i.e. does not allow narrow load starting from the 2nd byte.
- Add some narrow load tests to the test_verifier's sock.c
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

2 files changed, 107 insertions, 7 deletions

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index bd169a7bcc93..7f58828755fd 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -194,6 +194,7 @@ enum bpf_arg_type {
 	ARG_ANYTHING,		/* any (initialized) argument is ok */
 	ARG_PTR_TO_SOCKET,	/* pointer to bpf_sock */
 	ARG_PTR_TO_SPIN_LOCK,	/* pointer to bpf_spin_lock */
+	ARG_PTR_TO_SOCK_COMMON,	/* pointer to sock_common */
 };
 
 /* type of values returned from helper functions */
@@ -203,6 +204,7 @@ enum bpf_return_type {
 	RET_PTR_TO_MAP_VALUE,		/* returns a pointer to map elem value */
 	RET_PTR_TO_MAP_VALUE_OR_NULL,	/* returns a pointer to map elem value or NULL */
 	RET_PTR_TO_SOCKET_OR_NULL,	/* returns a pointer to a socket or NULL */
+	RET_PTR_TO_TCP_SOCK_OR_NULL,	/* returns a pointer to a tcp_sock or NULL */
 };
 
 /* eBPF function prototype used by verifier to allow BPF_CALLs from eBPF programs
@@ -256,6 +258,10 @@ enum bpf_reg_type {
 	PTR_TO_FLOW_KEYS,	 /* reg points to bpf_flow_keys */
 	PTR_TO_SOCKET,		 /* reg points to struct bpf_sock */
 	PTR_TO_SOCKET_OR_NULL,	 /* reg points to struct bpf_sock or NULL */
+	PTR_TO_SOCK_COMMON,	 /* reg points to sock_common */
+	PTR_TO_SOCK_COMMON_OR_NULL, /* reg points to sock_common or NULL */
+	PTR_TO_TCP_SOCK,	 /* reg points to struct tcp_sock */
+	PTR_TO_TCP_SOCK_OR_NULL, /* reg points to struct tcp_sock or NULL */
 };
 
 /* The information passed from prog-specific *_is_valid_access
@@ -920,6 +926,9 @@ void bpf_user_rnd_init_once(void);
 u64 bpf_user_rnd_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 
 #if defined(CONFIG_NET)
+bool bpf_sock_common_is_valid_access(int off, int size,
+				     enum bpf_access_type type,
+				     struct bpf_insn_access_aux *info);
 bool bpf_sock_is_valid_access(int off, int size, enum bpf_access_type type,
 			      struct bpf_insn_access_aux *info);
 u32 bpf_sock_convert_ctx_access(enum bpf_access_type type,
@@ -928,6 +937,12 @@ u32 bpf_sock_convert_ctx_access(enum bpf_access_type type,
 				struct bpf_prog *prog,
 				u32 *target_size);
 #else
+static inline bool bpf_sock_common_is_valid_access(int off, int size,
+						   enum bpf_access_type type,
+						   struct bpf_insn_access_aux *info)
+{
+	return false;
+}
 static inline bool bpf_sock_is_valid_access(int off, int size,
 					    enum bpf_access_type type,
 					    struct bpf_insn_access_aux *info)
@@ -944,4 +959,31 @@ static inline u32 bpf_sock_convert_ctx_access(enum bpf_access_type type,
 }
 #endif
 
+#ifdef CONFIG_INET
+bool bpf_tcp_sock_is_valid_access(int off, int size, enum bpf_access_type type,
+				  struct bpf_insn_access_aux *info);
+
+u32 bpf_tcp_sock_convert_ctx_access(enum bpf_access_type type,
+				    const struct bpf_insn *si,
+				    struct bpf_insn *insn_buf,
+				    struct bpf_prog *prog,
+				    u32 *target_size);
+#else
+static inline bool bpf_tcp_sock_is_valid_access(int off, int size,
+						enum bpf_access_type type,
+						struct bpf_insn_access_aux *info)
+{
+	return false;
+}
+
+static inline u32 bpf_tcp_sock_convert_ctx_access(enum bpf_access_type type,
+						  const struct bpf_insn *si,
+						  struct bpf_insn *insn_buf,
+						  struct bpf_prog *prog,
+						  u32 *target_size)
+{
+	return 0;
+}
+#endif /* CONFIG_INET */
+
 #endif /* _LINUX_BPF_H */
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 1777fa0c61e4..25c8c0e62ecf 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -2329,6 +2329,23 @@ union bpf_attr {
  *		"**y**".
  *	Return
  *		0
+ *
+ * struct bpf_sock *bpf_sk_fullsock(struct bpf_sock *sk)
+ *	Description
+ *		This helper gets a **struct bpf_sock** pointer such
+ *		that all the fields in bpf_sock can be accessed.
+ *	Return
+ *		A **struct bpf_sock** pointer on success, or NULL in
+ *		case of failure.
+ *
+ * struct bpf_tcp_sock *bpf_tcp_sock(struct bpf_sock *sk)
+ *	Description
+ *		This helper gets a **struct bpf_tcp_sock** pointer from a
+ *		**struct bpf_sock** pointer.
+ *
+ *	Return
+ *		A **struct bpf_tcp_sock** pointer on success, or NULL in
+ *		case of failure.
  */
 #define __BPF_FUNC_MAPPER(FN)		\
 	FN(unspec),			\
@@ -2425,7 +2442,9 @@ union bpf_attr {
 	FN(msg_pop_data),		\
 	FN(rc_pointer_rel),		\
 	FN(spin_lock),			\
-	FN(spin_unlock),
+	FN(spin_unlock),		\
+	FN(sk_fullsock),		\
+	FN(tcp_sock),
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
  * function eBPF program intends to call
@@ -2545,6 +2564,7 @@ struct __sk_buff {
 	__u64 tstamp;
 	__u32 wire_len;
 	__u32 gso_segs;
+	__bpf_md_ptr(struct bpf_sock *, sk);
 };
 
 struct bpf_tunnel_key {
@@ -2596,14 +2616,52 @@ struct bpf_sock {
 	__u32 protocol;
 	__u32 mark;
 	__u32 priority;
-	__u32 src_ip4;		/* Allows 1,2,4-byte read.
-				 * Stored in network byte order.
+	/* IP address also allows 1 and 2 bytes access */
+	__u32 src_ip4;
+	__u32 src_ip6[4];
+	__u32 src_port;		/* host byte order */
+	__u32 dst_port;		/* network byte order */
+	__u32 dst_ip4;
+	__u32 dst_ip6[4];
+	__u32 state;
+};
+
+struct bpf_tcp_sock {
+	__u32 snd_cwnd;		/* Sending congestion window		*/
+	__u32 srtt_us;		/* smoothed round trip time << 3 in usecs */
+	__u32 rtt_min;
+	__u32 snd_ssthresh;	/* Slow start size threshold		*/
+	__u32 rcv_nxt;		/* What we want to receive next		*/
+	__u32 snd_nxt;		/* Next sequence we send		*/
+	__u32 snd_una;		/* First byte we want an ack for	*/
+	__u32 mss_cache;	/* Cached effective mss, not including SACKS */
+	__u32 ecn_flags;	/* ECN status bits.			*/
+	__u32 rate_delivered;	/* saved rate sample: packets delivered */
+	__u32 rate_interval_us;	/* saved rate sample: time elapsed */
+	__u32 packets_out;	/* Packets which are "in flight"	*/
+	__u32 retrans_out;	/* Retransmitted packets out		*/
+	__u32 total_retrans;	/* Total retransmits for entire connection */
+	__u32 segs_in;		/* RFC4898 tcpEStatsPerfSegsIn
+				 * total number of segments in.
 				 */
-	__u32 src_ip6[4];	/* Allows 1,2,4-byte read.
-				 * Stored in network byte order.
+	__u32 data_segs_in;	/* RFC4898 tcpEStatsPerfDataSegsIn
+				 * total number of data segments in.
+				 */
+	__u32 segs_out;		/* RFC4898 tcpEStatsPerfSegsOut
+				 * The total number of segments sent.
+				 */
+	__u32 data_segs_out;	/* RFC4898 tcpEStatsPerfDataSegsOut
+				 * total number of data segments sent.
+				 */
+	__u32 lost_out;		/* Lost packets			*/
+	__u32 sacked_out;	/* SACK'd packets			*/
+	__u64 bytes_received;	/* RFC4898 tcpEStatsAppHCThruOctetsReceived
+				 * sum(delta(rcv_nxt)), or how many bytes
+				 * were acked.
 				 */
-	__u32 src_port;		/* Allows 4-byte read.
-				 * Stored in host byte order
+	__u64 bytes_acked;	/* RFC4898 tcpEStatsAppHCThruOctetsAcked
+				 * sum(delta(snd_una)), or how many bytes
+				 * were acked.
 				 */
 };