From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lawrence Brakmo Subject: [RFC PATCH net-next 12/15] bpf: Adds support for setting initial cwnd Date: Tue, 13 Jun 2017 11:00:01 -0700 Message-ID: <20170613180004.3008403-13-brakmo@fb.com> References: <20170613180004.3008403-1-brakmo@fb.com> Mime-Version: 1.0 Content-Type: text/plain Cc: Kernel Team , Blake Matheny , "Alexei Starovoitov" , Daniel Borkmann , David Ahern To: netdev Return-path: Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:44268 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753342AbdFMSAM (ORCPT ); Tue, 13 Jun 2017 14:00:12 -0400 Received: from pps.filterd (m0001255.ppops.net [127.0.0.1]) by mx0b-00082601.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v5DHvBH9000951 for ; Tue, 13 Jun 2017 11:00:11 -0700 Received: from mail.thefacebook.com ([199.201.64.23]) by mx0b-00082601.pphosted.com with ESMTP id 2b29g4bt3a-9 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Tue, 13 Jun 2017 11:00:11 -0700 Received: from facebook.com (2401:db00:11:d025:face:0:13:0) by mx-out.facebook.com (10.102.107.97) with ESMTP id 2375416c506211e79a800002c99331b0-78d3a8f0 for ; Tue, 13 Jun 2017 11:00:08 -0700 In-Reply-To: <20170613180004.3008403-1-brakmo@fb.com> Sender: netdev-owner@vger.kernel.org List-ID: Adds a new bpf_setsockopt for TCP sockets, TCP_BPF_IW, which sets the initial congestion window. This can be used when the hosts are far apart (large RTTs) and it is safe to start with a large inital cwnd. Signed-off-by: Lawrence Brakmo --- include/uapi/linux/bpf.h | 2 ++ net/core/filter.c | 14 +++++++++++++- 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index b86aacc..9895672 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -734,4 +734,6 @@ enum { */ }; +#define TCP_BPF_IW 1001 /* Set TCP initial congestion window */ + #endif /* _UAPI__LINUX_BPF_H__ */ diff --git a/net/core/filter.c b/net/core/filter.c index 5e0cb4e..7b4458d 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2705,7 +2705,19 @@ BPF_CALL_5(bpf_setsockopt, struct bpf_socket_ops_kern *, bpf_socket, tcp_reinit_congestion_control(sk, inet_csk(sk)->icsk_ca_ops); } else { - ret = -EINVAL; + struct tcp_sock *tp = tcp_sk(sk); + + val = *((int *)optval); + switch (optname) { + case TCP_BPF_IW: + if (val <= 0 || tp->data_segs_out > 0) + ret = -EINVAL; + else + tp->snd_cwnd = val; + break; + default: + ret = -EINVAL; + } } } else { ret = -EINVAL; -- 2.9.3