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linux-next/samples/bpf/tcp_rwnd_kern.c

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bpf: Sample bpf program to set initial window 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> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-01 11:02:45 +08:00
/* 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 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).
*
samples: bpf: remove load_sock_ops in favour of bpftool bpftool can do all the things load_sock_ops used to do, and more. Point users to bpftool instead of maintaining this sample utility. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-02-28 11:04:11 +08:00
* Use "bpftool cgroup attach $cg sock_ops $prog" to load this BPF program.
bpf: Sample bpf program to set initial window 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> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-01 11:02:45 +08:00
*/
#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>
samples/bpf: Use consistent include paths for libbpf Fix all files in samples/bpf to include libbpf header files with the bpf/ prefix, to be consistent with external users of the library. Also ensure that all includes of exported libbpf header files (those that are exported on 'make install' of the library) use bracketed includes instead of quoted. To make sure no new files are introduced that doesn't include the bpf/ prefix in its include, remove tools/lib/bpf from the include path entirely, and use tools/lib instead. Fixes: 6910d7d3867a ("selftests/bpf: Ensure bpf_helper_defs.h are taken from selftests dir") Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/157952560911.1683545.8795966751309534150.stgit@toke.dk
2020-01-20 21:06:49 +08:00
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_endian.h>
bpf: Sample bpf program to set initial window 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> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-01 11:02:45 +08:00
#define DEBUG 1
SEC("sockops")
int bpf_rwnd(struct bpf_sock_ops *skops)
{
int rv = -1;
int op;
/* For testing purposes, only execute rest of BPF program
* if neither port numberis 55601
*/
if (bpf_ntohl(skops->remote_port) !=
bpf: Fix tcp_rwnd_kern.c sample program The program was returning -1 in some cases which is not allowed by the verifier any longer. Fixes: 390ee7e29fc8 ("bpf: enforce return code for cgroup-bpf programs") Signed-off-by: Lawrence Brakmo <brakmo@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-11 14:19:51 +08:00
55601 && skops->local_port != 55601) {
skops->reply = -1;
return 1;
}
bpf: Sample bpf program to set initial window 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> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-01 11:02:45 +08:00
op = (int) skops->op;
#ifdef DEBUG
bpf_printk("BPF command: %d\n", op);
#endif
/* Check for RWND_INIT operation and IPv6 addresses */
if (op == BPF_SOCK_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] ||
(bpf_ntohl(skops->local_ip6[1]) & 0xfffff000) !=
(bpf_ntohl(skops->remote_ip6[1]) & 0xfffff000))
rv = 40;
}
#ifdef DEBUG
bpf_printk("Returning %d\n", rv);
#endif
skops->reply = rv;
return 1;
}
char _license[] SEC("license") = "GPL";
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