From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lawrence Brakmo Subject: [PATCH net-next v4 13/16] bpf: Sample BPF program to set initial cwnd Date: Wed, 28 Jun 2017 10:31:21 -0700 Message-ID: <20170628173124.3299500-14-brakmo@fb.com> References: <20170628173124.3299500-1-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 mx0a-00082601.pphosted.com ([67.231.145.42]:41135 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751928AbdF1Rbe (ORCPT ); Wed, 28 Jun 2017 13:31:34 -0400 Received: from pps.filterd (m0044008.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v5SHSwDo032419 for ; Wed, 28 Jun 2017 10:31:34 -0700 Received: from mail.thefacebook.com ([199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2bcf508g2g-3 (version=TLSv1 cipher=ECDHE-RSA-AES256-SHA bits=256 verify=NOT) for ; Wed, 28 Jun 2017 10:31:34 -0700 Received: from facebook.com (2401:db00:11:d025:face:0:13:0) by mx-out.facebook.com (10.212.236.87) with ESMTP id a0e49ece5c2711e7ba3f0002c9521c9e-f26ac150 for ; Wed, 28 Jun 2017 10:31:33 -0700 In-Reply-To: <20170628173124.3299500-1-brakmo@fb.com> Sender: netdev-owner@vger.kernel.org List-ID: Sample BPF program that assumes hosts are far away (i.e. large RTTs) and sets initial cwnd and initial receive window to 40 packets, send and receive buffers to 1.5MB. In practice there would be a test to insure the hosts are actually far enough away. Signed-off-by: Lawrence Brakmo --- samples/bpf/Makefile | 1 + samples/bpf/tcp_iw_kern.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 80 insertions(+) create mode 100644 samples/bpf/tcp_iw_kern.c diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 6fdf32d..242d76e 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -117,6 +117,7 @@ always += tcp_synrto_kern.o always += tcp_rwnd_kern.o always += tcp_bufs_kern.o always += tcp_cong_kern.o +always += tcp_iw_kern.o HOSTCFLAGS += -I$(objtree)/usr/include HOSTCFLAGS += -I$(srctree)/tools/lib/ diff --git a/samples/bpf/tcp_iw_kern.c b/samples/bpf/tcp_iw_kern.c new file mode 100644 index 0000000..28626f9 --- /dev/null +++ b/samples/bpf/tcp_iw_kern.c @@ -0,0 +1,79 @@ +/* Copyright (c) 2017 Facebook + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + * + * BPF program to set initial congestion window and initial receive + * window to 40 packets and send and receive buffers to 1.5MB. This + * would usually be done after doing appropriate checks that indicate + * the hosts are far enough away (i.e. large RTT). + */ + +#include +#include +#include +#include +#include +#include "bpf_helpers.h" + +#define DEBUG 1 + +SEC("sockops") +int bpf_iw(struct bpf_sock_ops *skops) +{ + char fmt1[] = "BPF command: %d\n"; + char fmt2[] = " Returning %d\n"; + int bufsize = 1500000; + int rwnd_init = 40; + int iw = 40; + int rv = 0; + int op; + + /* For testing purposes, only execute rest of BPF program + * if neither port numberis 55601 + */ + if (skops->remote_port != 55601 && skops->local_port != 55601) + return -1; + + op = (int) skops->op; + +#ifdef DEBUG + bpf_trace_printk(fmt1, sizeof(fmt1), op); +#endif + + /* Usually there would be a check to insure the hosts are far + * from each other so it makes sense to increase buffer sizes + */ + switch (op) { + case BPF_SOCK_OPS_RWND_INIT: + rv = rwnd_init; + break; + case BPF_SOCK_OPS_TCP_CONNECT_CB: + /* Set sndbuf and rcvbuf of active connections */ + rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize, + sizeof(bufsize)); + rv = rv*100 + bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF, + &bufsize, sizeof(bufsize)); + break; + case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB: + rv = bpf_setsockopt(skops, SOL_TCP, TCP_BPF_IW, &iw, + sizeof(iw)); + break; + case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: + /* Set sndbuf and rcvbuf of passive connections */ + rv = bpf_setsockopt(skops, SOL_SOCKET, SO_SNDBUF, &bufsize, + sizeof(bufsize)); + rv = rv*100 + bpf_setsockopt(skops, SOL_SOCKET, SO_RCVBUF, + &bufsize, sizeof(bufsize)); + break; + default: + rv = -1; + } +#ifdef DEBUG + bpf_trace_printk(fmt2, sizeof(fmt2), rv); +#endif + skops->reply = rv; + return 1; +} +char _license[] SEC("license") = "GPL"; -- 2.9.3