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>,
David Ahern <dsa@cumulusnetworks•com>
Subject: [RFC PATCH net-next v2 06/15] bpf: Sample bpf program to set initial window
Date: Thu, 15 Jun 2017 13:08:35 -0700 [thread overview]
Message-ID: <20170615200844.2752485-7-brakmo@fb.com> (raw)
In-Reply-To: <20170615200844.2752485-1-brakmo@fb.com>
The sample bpf program, tcp_rwnd_kern.c, sets the initial
advertized window to 40 packets in an environment where
distinct IPv6 prefixes indicate that both hosts are not
in the same data center.
Signed-off-by: Lawrence Brakmo <brakmo@fb•com>
---
samples/bpf/Makefile | 1 +
samples/bpf/tcp_rwnd_kern.c | 55 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 56 insertions(+)
create mode 100644 samples/bpf/tcp_rwnd_kern.c
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 21cb016..9aca209 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -114,6 +114,7 @@ always += xdp_tx_iptunnel_kern.o
always += test_map_in_map_kern.o
always += cookie_uid_helper_example.o
always += tcp_synrto_kern.o
+always += tcp_rwnd_kern.o
HOSTCFLAGS += -I$(objtree)/usr/include
HOSTCFLAGS += -I$(srctree)/tools/lib/
diff --git a/samples/bpf/tcp_rwnd_kern.c b/samples/bpf/tcp_rwnd_kern.c
new file mode 100644
index 0000000..f01b6d4
--- /dev/null
+++ b/samples/bpf/tcp_rwnd_kern.c
@@ -0,0 +1,55 @@
+/*
+ * BPF program to set initial receive window to 40 packets when using IPv6
+ * and the first 5.5 bytes of the IPv6 addresses are not the same (in this
+ * example that means both hosts are not the same datacenter.
+ */
+
+#include <uapi/linux/bpf.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"
+
+#define DEBUG 1
+
+SEC("sockops")
+int bpf_rwnd(struct bpf_socket_ops *skops)
+{
+ char fmt1[] = "BPF command: %d\n";
+ char fmt2[] = " Returning %d\n";
+ int rv = -1;
+ 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
+
+ /* Check for RWND_INIT operation and IPv6 addresses */
+ if (op == BPF_SOCKET_OPS_RWND_INIT &&
+ skops->family == AF_INET6) {
+
+ /* If the first 5.5 bytes of the IPv6 address are not the same
+ * then both hosts are not in the same datacenter
+ * so use a larger initial advertized window (40 packets)
+ */
+ if (skops->local_ip6[0] != skops->remote_ip6[0] ||
+ (skops->local_ip6[1] & 0xfffff000) !=
+ (skops->remote_ip6[1] & 0xfffff000))
+ bpf_trace_printk(fmt2, sizeof(fmt2), -1);
+ rv = 40;
+ }
+#ifdef DEBUG
+ bpf_trace_printk(fmt2, sizeof(fmt2), rv);
+#endif
+ return rv;
+}
+char _license[] SEC("license") = "GPL";
--
2.9.3
next prev parent reply other threads:[~2017-06-15 20:08 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-15 20:08 [RFC PATCH net-next v2 00/15] bpf: BPF support for socket ops Lawrence Brakmo
2017-06-15 20:08 ` [RFC PATCH net-next v2 01/15] " Lawrence Brakmo
2017-06-16 12:07 ` Daniel Borkmann
2017-06-16 23:41 ` Lawrence Brakmo
2017-06-19 18:44 ` Daniel Borkmann
2017-06-19 20:49 ` Lawrence Brakmo
2017-06-17 21:48 ` Lawrence Brakmo
2017-06-19 18:52 ` Daniel Borkmann
2017-06-19 20:49 ` Lawrence Brakmo
2017-06-15 20:08 ` [RFC PATCH net-next v2 02/15] bpf: program to load socketops BPF programs Lawrence Brakmo
2017-06-15 20:08 ` [RFC PATCH net-next v2 03/15] bpf: Support for per connection SYN/SYN-ACK RTOs Lawrence Brakmo
2017-06-15 20:08 ` [RFC PATCH net-next v2 04/15] bpf: Sample bpf program to set " Lawrence Brakmo
2017-06-15 20:08 ` [RFC PATCH net-next v2 05/15] bpf: Support for setting initial receive window Lawrence Brakmo
2017-06-15 20:08 ` Lawrence Brakmo [this message]
2017-06-15 20:08 ` [RFC PATCH net-next v2 07/15] bpf: Add setsockopt helper function to bpf Lawrence Brakmo
2017-06-16 13:27 ` Daniel Borkmann
2017-06-17 23:17 ` Lawrence Brakmo
2017-06-15 20:08 ` [RFC PATCH net-next v2 08/15] bpf: Add TCP connection BPF callbacks Lawrence Brakmo
2017-06-15 20:08 ` [RFC PATCH net-next v2 09/15] bpf: Sample BPF program to set buffer sizes Lawrence Brakmo
2017-06-15 20:08 ` [RFC PATCH net-next v2 10/15] bpf: Add support for changing congestion control Lawrence Brakmo
2017-06-16 13:58 ` Daniel Borkmann
2017-06-18 2:39 ` Lawrence Brakmo
2017-06-19 22:34 ` Daniel Borkmann
2017-06-20 0:35 ` Lawrence Brakmo
2017-06-15 20:08 ` [RFC PATCH net-next v2 11/15] bpf: Sample BPF program to set " Lawrence Brakmo
2017-06-15 20:08 ` [RFC PATCH net-next v2 12/15] bpf: Adds support for setting initial cwnd Lawrence Brakmo
2017-06-15 20:08 ` [RFC PATCH net-next v2 13/15] bpf: Sample BPF program to set " Lawrence Brakmo
2017-06-15 20:08 ` [RFC PATCH net-next v2 14/15] bpf: Adds support for setting sndcwnd clamp Lawrence Brakmo
2017-06-15 20:08 ` [RFC PATCH net-next v2 15/15] bpf: Sample bpf program to set " Lawrence Brakmo
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