Merge branch 'bpf-more-sock_ops-callbacks'

Lawrence Brakmo says:

====================
This patchset adds support for:

- direct R or R/W access to many tcp_sock fields
- passing up to 4 arguments to sock_ops BPF functions
- tcp_sock field bpf_sock_ops_cb_flags for controlling callbacks
- optionally calling sock_ops BPF program when RTO fires
- optionally calling sock_ops BPF program when packet is retransmitted
- optionally calling sock_ops BPF program when TCP state changes
- access to tclass and sk_txhash
- new selftest

v2: Fixed commit message 0/11. The commit is to "bpf-next" but the patch
    below used "bpf" and Patchwork didn't work correctly.
v3: Cleaned RTO callback as per  Yuchung's comment
    Added BPF enum for TCP states as per  Alexei's comment
v4: Fixed compile warnings related to detecting changes between TCP
    internal states and the BPF defined states.
v5: Fixed comment issues in some selftest files
    Fixed accesss issue with u64 fields in bpf_sock_ops struct
v6: Made fixes based on comments form Eric Dumazet:
    The field bpf_sock_ops_cb_flags was addded in a hole on 64bit kernels
    Field bpf_sock_ops_cb_flags is now set through a helper function
    which returns an error when a BPF program tries to set bits for
    callbacks that are not supported in the current kernel.
    Added a comment indicating that when adding fields to bpf_sock_ops_kern
    they should be added before the field named "temp" if they need to be
    cleared before calling the BPF function.
v7: Enfornced fields "op" and "replylong[1] .. replylong[3]" not be writable
    based on comments form Eric Dumazet and Alexei Starovoitov.
    Filled 32 bit hole in bpf_sock_ops struct with sk_txhash based on
    comments from Daniel Borkmann.
    Removed unused functions (tcp_call_bpf_1arg, tcp_call_bpf_4arg) based
    on comments from Daniel Borkmann.
v8: Add commit message 00/12
    Add Acked-by as appropriate
v9: Moved the bug fix to the front of the patchset
    Changed RETRANS_CB so it is always called (before it was only called if
    the retransmit succeeded). It is now called with an extra argument, the
    return value of tcp_transmit_skb (0 => success). Based on comments
    from Yuchung Cheng.
    Added support for reading 2 new fields, sacked_out and lost_out, based on
    comments from Yuchung Cheng.
v10: Moved the callback flags from include/uapi/linux/tcp.h to
     include/uapi/linux/bpf.h
     Cleaned up the test in selftest. Added a timeout so it always completes,
     even if the client is not communicating with the server. Made it faster
     by removing the sleeps. Made sure it works even when called back-to-back
     20 times.

Consists of the following patches:
[PATCH bpf-next v10 01/12] bpf: Only reply field should be writeable
[PATCH bpf-next v10 02/12] bpf: Make SOCK_OPS_GET_TCP size
[PATCH bpf-next v10 03/12] bpf: Make SOCK_OPS_GET_TCP struct
[PATCH bpf-next v10 04/12] bpf: Add write access to tcp_sock and sock
[PATCH bpf-next v10 05/12] bpf: Support passing args to sock_ops bpf
[PATCH bpf-next v10 06/12] bpf: Adds field bpf_sock_ops_cb_flags to
[PATCH bpf-next v10 07/12] bpf: Add sock_ops RTO callback
[PATCH bpf-next v10 08/12] bpf: Add support for reading sk_state and
[PATCH bpf-next v10 09/12] bpf: Add sock_ops R/W access to tclass
[PATCH bpf-next v10 10/12] bpf: Add BPF_SOCK_OPS_RETRANS_CB
[PATCH bpf-next v10 11/12] bpf: Add BPF_SOCK_OPS_STATE_CB
[PATCH bpf-next v10 12/12] bpf: add selftest for tcpbpf
====================

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

1 files changed, 81 insertions, 3 deletions

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 406c19d6016b..db6bdc375126 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -642,6 +642,14 @@ union bpf_attr {
  *     @optlen: length of optval in bytes
  *     Return: 0 or negative error
  *
+ * int bpf_sock_ops_cb_flags_set(bpf_sock_ops, flags)
+ *     Set callback flags for sock_ops
+ *     @bpf_sock_ops: pointer to bpf_sock_ops_kern struct
+ *     @flags: flags value
+ *     Return: 0 for no error
+ *             -EINVAL if there is no full tcp socket
+ *             bits in flags that are not supported by current kernel
+ *
  * int bpf_skb_adjust_room(skb, len_diff, mode, flags)
  *     Grow or shrink room in sk_buff.
  *     @skb: pointer to skb
@@ -748,7 +756,8 @@ union bpf_attr {
 	FN(perf_event_read_value),	\
 	FN(perf_prog_read_value),	\
 	FN(getsockopt),			\
-	FN(override_return),
+	FN(override_return),		\
+	FN(sock_ops_cb_flags_set),
 
 /* integer value in 'imm' field of BPF_CALL instruction selects which helper
  * function eBPF program intends to call
@@ -952,8 +961,9 @@ struct bpf_map_info {
 struct bpf_sock_ops {
 	__u32 op;
 	union {
-		__u32 reply;
-		__u32 replylong[4];
+		__u32 args[4];		/* Optionally passed to bpf program */
+		__u32 reply;		/* Returned by bpf program	    */
+		__u32 replylong[4];	/* Optionally returned by bpf prog  */
 	};
 	__u32 family;
 	__u32 remote_ip4;	/* Stored in network byte order */
@@ -968,8 +978,39 @@ struct bpf_sock_ops {
 				 */
 	__u32 snd_cwnd;
 	__u32 srtt_us;		/* Averaged RTT << 3 in usecs */
+	__u32 bpf_sock_ops_cb_flags; /* flags defined in uapi/linux/tcp.h */
+	__u32 state;
+	__u32 rtt_min;
+	__u32 snd_ssthresh;
+	__u32 rcv_nxt;
+	__u32 snd_nxt;
+	__u32 snd_una;
+	__u32 mss_cache;
+	__u32 ecn_flags;
+	__u32 rate_delivered;
+	__u32 rate_interval_us;
+	__u32 packets_out;
+	__u32 retrans_out;
+	__u32 total_retrans;
+	__u32 segs_in;
+	__u32 data_segs_in;
+	__u32 segs_out;
+	__u32 data_segs_out;
+	__u32 lost_out;
+	__u32 sacked_out;
+	__u32 sk_txhash;
+	__u64 bytes_received;
+	__u64 bytes_acked;
 };
 
+/* Definitions for bpf_sock_ops_cb_flags */
+#define BPF_SOCK_OPS_RTO_CB_FLAG	(1<<0)
+#define BPF_SOCK_OPS_RETRANS_CB_FLAG	(1<<1)
+#define BPF_SOCK_OPS_STATE_CB_FLAG	(1<<2)
+#define BPF_SOCK_OPS_ALL_CB_FLAGS       0x7		/* Mask of all currently
+							 * supported cb flags
+							 */
+
 /* List of known BPF sock_ops operators.
  * New entries can only be added at the end
  */
@@ -1003,6 +1044,43 @@ enum {
 					 * a congestion threshold. RTTs above
 					 * this indicate congestion
 					 */
+	BPF_SOCK_OPS_RTO_CB,		/* Called when an RTO has triggered.
+					 * Arg1: value of icsk_retransmits
+					 * Arg2: value of icsk_rto
+					 * Arg3: whether RTO has expired
+					 */
+	BPF_SOCK_OPS_RETRANS_CB,	/* Called when skb is retransmitted.
+					 * Arg1: sequence number of 1st byte
+					 * Arg2: # segments
+					 * Arg3: return value of
+					 *       tcp_transmit_skb (0 => success)
+					 */
+	BPF_SOCK_OPS_STATE_CB,		/* Called when TCP changes state.
+					 * Arg1: old_state
+					 * Arg2: new_state
+					 */
+};
+
+/* List of TCP states. There is a build check in net/ipv4/tcp.c to detect
+ * changes between the TCP and BPF versions. Ideally this should never happen.
+ * If it does, we need to add code to convert them before calling
+ * the BPF sock_ops function.
+ */
+enum {
+	BPF_TCP_ESTABLISHED = 1,
+	BPF_TCP_SYN_SENT,
+	BPF_TCP_SYN_RECV,
+	BPF_TCP_FIN_WAIT1,
+	BPF_TCP_FIN_WAIT2,
+	BPF_TCP_TIME_WAIT,
+	BPF_TCP_CLOSE,
+	BPF_TCP_CLOSE_WAIT,
+	BPF_TCP_LAST_ACK,
+	BPF_TCP_LISTEN,
+	BPF_TCP_CLOSING,	/* Now a valid state */
+	BPF_TCP_NEW_SYN_RECV,
+
+	BPF_TCP_MAX_STATES	/* Leave at the end! */
 };
 
 #define TCP_BPF_IW		1001	/* Set TCP initial congestion window */