From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lawrence Brakmo Subject: [PATCH bpf-next v10 10/12] bpf: Add BPF_SOCK_OPS_RETRANS_CB Date: Thu, 25 Jan 2018 16:14:14 -0800 Message-ID: <20180126001416.1118158-11-brakmo@fb.com> References: <20180126001416.1118158-1-brakmo@fb.com> Mime-Version: 1.0 Content-Type: text/plain Cc: Kernel Team , Blake Matheny , Alexei Starovoitov , Daniel Borkmann , Eric Dumazet , Neal Cardwell , Yuchung Cheng To: netdev Return-path: Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:50466 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751782AbeAZAOY (ORCPT ); Thu, 25 Jan 2018 19:14:24 -0500 Received: from pps.filterd (m0044008.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w0Q0EKbI027330 for ; Thu, 25 Jan 2018 16:14:24 -0800 Received: from mail.thefacebook.com ([199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2fqng78pwb-11 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Thu, 25 Jan 2018 16:14:24 -0800 In-Reply-To: <20180126001416.1118158-1-brakmo@fb.com> Sender: netdev-owner@vger.kernel.org List-ID: Adds support for calling sock_ops BPF program when there is a retransmission. Three arguments are used; one for the sequence number, another for the number of segments retransmitted, and the last one for the return value of tcp_transmit_skb (0 => success). Does not include syn-ack retransmissions. New op: BPF_SOCK_OPS_RETRANS_CB. Signed-off-by: Lawrence Brakmo --- include/uapi/linux/bpf.h | 9 ++++++++- net/ipv4/tcp_output.c | 4 ++++ 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 46520ea..31c93a0b 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -1005,7 +1005,8 @@ struct bpf_sock_ops { /* Definitions for bpf_sock_ops_cb_flags */ #define BPF_SOCK_OPS_RTO_CB_FLAG (1<<0) -#define BPF_SOCK_OPS_ALL_CB_FLAGS 0x1 /* Mask of all currently +#define BPF_SOCK_OPS_RETRANS_CB_FLAG (1<<1) +#define BPF_SOCK_OPS_ALL_CB_FLAGS 0x3 /* Mask of all currently * supported cb flags */ @@ -1047,6 +1048,12 @@ 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 + * Arg3: return value of + * tcp_transmit_skb (0 => success) + */ }; #define TCP_BPF_IW 1001 /* Set TCP initial congestion window */ diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index d12f7f7..e9f985e 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2905,6 +2905,10 @@ int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs) err = tcp_transmit_skb(sk, skb, 1, GFP_ATOMIC); } + if (BPF_SOCK_OPS_TEST_FLAG(tp, BPF_SOCK_OPS_RETRANS_CB_FLAG)) + tcp_call_bpf_3arg(sk, BPF_SOCK_OPS_RETRANS_CB, + TCP_SKB_CB(skb)->seq, segs, err); + if (likely(!err)) { TCP_SKB_CB(skb)->sacked |= TCPCB_EVER_RETRANS; trace_tcp_retransmit_skb(sk, skb); -- 2.9.5