From: Lawrence Brakmo <brakmo@fb•com>
To: netdev <netdev@vger•kernel.org>
Cc: Kernel Team <kernel-team@fb•com>, Alexei Starovoitov <ast@fb•com>,
"Daniel Borkmann" <daniel@iogearbox•net>,
Blake Matheny <bmatheny@fb•com>,
"Lawrence Brakmo" <brakmo@fb•com>
Subject: [PATCH net-next 4/5] bpf: sample BPF_SOCKET_OPS_BASE_RTT program
Date: Fri, 20 Oct 2017 11:05:42 -0700 [thread overview]
Message-ID: <20171020180543.4156833-5-brakmo@fb.com> (raw)
In-Reply-To: <20171020180543.4156833-1-brakmo@fb.com>
Sample socket_ops BPF program to test the BPF helper function
bpf_getsocketops and the new socket_ops op BPF_SOCKET_OPS_BASE_RTT.
The program provides a base RTT of 80us when the calling flow is
within a DC (as determined by the IPV6 prefix) and the congestion
algorithm is "nv".
Signed-off-by: Lawrence Brakmo <brakmo@fb•com>
Acked-by: Daniel Borkmann <daniel@iogearbox•net>
Acked_by: Alexei Starovoitov <ast@fb•com>
---
samples/bpf/Makefile | 1 +
samples/bpf/tcp_basertt_kern.c | 78 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 79 insertions(+)
create mode 100644 samples/bpf/tcp_basertt_kern.c
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 3534ccf..ea2b9e6 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -129,6 +129,7 @@ always += tcp_bufs_kern.o
always += tcp_cong_kern.o
always += tcp_iw_kern.o
always += tcp_clamp_kern.o
+always += tcp_basertt_kern.o
always += xdp_redirect_kern.o
always += xdp_redirect_map_kern.o
always += xdp_redirect_cpu_kern.o
diff --git a/samples/bpf/tcp_basertt_kern.c b/samples/bpf/tcp_basertt_kern.c
new file mode 100644
index 0000000..4bf4fc5
--- /dev/null
+++ b/samples/bpf/tcp_basertt_kern.c
@@ -0,0 +1,78 @@
+/* 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 base_rtt to 80us when host is running TCP-NV and
+ * both hosts are in the same datacenter (as determined by IPv6 prefix).
+ *
+ * Use load_sock_ops to load this BPF program.
+ */
+
+#include <uapi/linux/bpf.h>
+#include <uapi/linux/tcp.h>
+#include <uapi/linux/if_ether.h>
+#include <uapi/linux/if_packet.h>
+#include <uapi/linux/ip.h>
+#include <linux/socket.h>
+#include "bpf_helpers.h"
+#include "bpf_endian.h"
+
+#define DEBUG 1
+
+#define bpf_printk(fmt, ...) \
+({ \
+ char ____fmt[] = fmt; \
+ bpf_trace_printk(____fmt, sizeof(____fmt), \
+ ##__VA_ARGS__); \
+})
+
+SEC("sockops")
+int bpf_basertt(struct bpf_sock_ops *skops)
+{
+ char cong[20];
+ char nv[] = "nv";
+ int rv = 0, n;
+ int op;
+
+ op = (int) skops->op;
+
+#ifdef DEBUG
+ bpf_printk("BPF command: %d\n", op);
+#endif
+
+ /* Check if both hosts are in the same datacenter. For this
+ * example they are if the 1st 5.5 bytes in the IPv6 address
+ * are the same.
+ */
+ if (skops->family == AF_INET6 &&
+ skops->local_ip6[0] == skops->remote_ip6[0] &&
+ (bpf_ntohl(skops->local_ip6[1]) & 0xfff00000) ==
+ (bpf_ntohl(skops->remote_ip6[1]) & 0xfff00000)) {
+ switch (op) {
+ case BPF_SOCK_OPS_BASE_RTT:
+ n = bpf_getsockopt(skops, SOL_TCP, TCP_CONGESTION,
+ cong, sizeof(cong));
+ if (!n && !__builtin_memcmp(cong, nv, sizeof(nv)+1)) {
+ /* Set base_rtt to 80us */
+ rv = 80;
+ } else if (n) {
+ rv = n;
+ } else {
+ rv = -1;
+ }
+ break;
+ default:
+ rv = -1;
+ }
+ } else {
+ rv = -1;
+ }
+#ifdef DEBUG
+ bpf_printk("Returning %d\n", rv);
+#endif
+ skops->reply = rv;
+ return 1;
+}
+char _license[] SEC("license") = "GPL";
--
2.9.5
next prev parent reply other threads:[~2017-10-20 18:06 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-20 18:05 [PATCH net-next 0/5] bpf: add support for BASE_RTT Lawrence Brakmo
2017-10-20 18:05 ` [PATCH net-next 1/5] bpf: add support for BPF_SOCK_OPS_BASE_RTT Lawrence Brakmo
2017-10-20 18:05 ` [PATCH net-next 2/5] bpf: Adding helper function bpf_getsockops Lawrence Brakmo
2017-10-20 18:05 ` [PATCH net-next 3/5] bpf: Add BPF_SOCKET_OPS_BASE_RTT support to tcp_nv Lawrence Brakmo
2017-10-21 19:37 ` Alexei Starovoitov
2017-10-20 18:05 ` Lawrence Brakmo [this message]
2017-10-20 18:05 ` [PATCH net-next 5/5] bpf: create samples/bpf/tcp_bpf.readme Lawrence Brakmo
2017-10-22 2:12 ` [PATCH net-next 0/5] bpf: add support for BASE_RTT David Miller
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