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From: Lawrence Brakmo <brakmo@fb.com>
To: netdev <netdev@vger.kernel.org>
Cc: Kernel Team <kernel-team@fb.com>, Blake Matheny <bmatheny@fb.com>,
	Alexei Starovoitov <ast@fb.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	Neal Cardwell <ncardwell@google.com>,
	Yuchung Cheng <ycheng@google.com>
Subject: [PATCH bpf-next v4 09/11] bpf: Add BPF_SOCK_OPS_RETRANS_CB
Date: Thu, 4 Jan 2018 15:55:31 -0800	[thread overview]
Message-ID: <20180104235533.3672006-10-brakmo@fb.com> (raw)
In-Reply-To: <20180104235533.3672006-1-brakmo@fb.com>

Adds support for calling sock_ops BPF program when there is a
retransmission. Two arguments are used; one for the sequence number and
other for the number of segments retransmitted. Does not include syn-ack
retransmissions.

New op: BPF_SOCK_OPS_RETRANS_CB.

Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
---
 include/uapi/linux/bpf.h | 4 ++++
 include/uapi/linux/tcp.h | 1 +
 net/ipv4/tcp_output.c    | 3 +++
 3 files changed, 8 insertions(+)

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index df1e73e..f6ab1da 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1023,6 +1023,10 @@ enum {
 					 * 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
+					 */
 };
 
 #define TCP_BPF_IW		1001	/* Set TCP initial congestion window */
diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h
index 089c19e..dc36d3c 100644
--- a/include/uapi/linux/tcp.h
+++ b/include/uapi/linux/tcp.h
@@ -261,6 +261,7 @@ struct tcp_md5sig {
 
 /* Definitions for bpf_sock_ops_flags */
 #define BPF_SOCK_OPS_RTO_CB_FLAG	(1<<0)
+#define BPF_SOCK_OPS_RETRANS_CB_FLAG	(1<<1)
 
 /* INET_DIAG_MD5SIG */
 struct tcp_diag_md5sig {
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index b093985..8109675 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2907,6 +2907,9 @@ int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs)
 	if (likely(!err)) {
 		TCP_SKB_CB(skb)->sacked |= TCPCB_EVER_RETRANS;
 		trace_tcp_retransmit_skb(sk, skb);
+		if (BPF_SOCK_OPS_TEST_FLAG(tp, BPF_SOCK_OPS_RETRANS_CB_FLAG))
+			tcp_call_bpf_2arg(sk, BPF_SOCK_OPS_RETRANS_CB,
+					  TCP_SKB_CB(skb)->seq, segs);
 	} else if (err != -EBUSY) {
 		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRETRANSFAIL);
 	}
-- 
2.9.5

  parent reply	other threads:[~2018-01-04 23:55 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-04 23:55 [PATCH bpf-next v4 00/11] bpf: More sock_ops callbacks Lawrence Brakmo
2018-01-04 23:55 ` [PATCH bpf-next v4 01/11] bpf: Make SOCK_OPS_GET_TCP size independent Lawrence Brakmo
2018-01-04 23:55 ` [PATCH bpf-next v4 02/11] bpf: Make SOCK_OPS_GET_TCP struct independent Lawrence Brakmo
2018-01-04 23:55 ` [PATCH bpf-next v4 03/11] bpf: Add write access to tcp_sock and sock fields Lawrence Brakmo
2018-01-04 23:55 ` [PATCH bpf-next v4 04/11] bpf: Support passing args to sock_ops bpf function Lawrence Brakmo
2018-01-04 23:55 ` [PATCH bpf-next v4 05/11] bpf: Adds field bpf_sock_ops_flags to tcp_sock Lawrence Brakmo
2018-01-04 23:55 ` [PATCH bpf-next v4 06/11] bpf: Add sock_ops RTO callback Lawrence Brakmo
2018-01-04 23:55 ` [PATCH bpf-next v4 07/11] bpf: Add support for reading sk_state and more Lawrence Brakmo
2018-01-06  1:46   ` Daniel Borkmann
2018-01-04 23:55 ` [PATCH bpf-next v4 08/11] bpf: Add sock_ops R/W access to tclass & sk_txhash Lawrence Brakmo
2018-01-04 23:55 ` Lawrence Brakmo [this message]
2018-01-04 23:55 ` [PATCH bpf-next v4 10/11] bpf: Add BPF_SOCK_OPS_STATE_CB Lawrence Brakmo
2018-01-04 23:55 ` [PATCH bpf-next v4 11/11] bpf: add selftest for tcpbpf Lawrence Brakmo

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