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selftests/bpf: Test a BPF CC writing sk_pacing_*

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Test whether a TCP CC implemented in BPF is allowed to write
sk_pacing_rate and sk_pacing_status in struct sock. This is needed when
cong_control() is implemented and used.

Signed-off-by: Jörn-Thorben Hinz <jthinz@mailbox.tu-berlin.de>
Link: https://lore.kernel.org/r/20220622191227.898118-4-jthinz@mailbox.tu-berlin.de
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Jörn-Thorben Hinz 2022-06-22 21:12:25 +02:00 committed by Alexei Starovoitov
parent 9f0265e921
commit 6e945d57cc
2 changed files with 79 additions and 0 deletions
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19
tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
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@ -9,6 +9,7 @@
#include "bpf_cubic.skel.h"
#include "bpf_tcp_nogpl.skel.h"
#include "bpf_dctcp_release.skel.h"
#include "tcp_ca_write_sk_pacing.skel.h"
#ifndef ENOTSUPP
#define ENOTSUPP 524
@ -322,6 +323,22 @@ static void test_rel_setsockopt(void)
bpf_dctcp_release__destroy(rel_skel);
}
static void test_write_sk_pacing(void)
{
struct tcp_ca_write_sk_pacing *skel;
struct bpf_link *link;
skel = tcp_ca_write_sk_pacing__open_and_load();
if (!ASSERT_OK_PTR(skel, "open_and_load"))
return;
link = bpf_map__attach_struct_ops(skel->maps.write_sk_pacing);
ASSERT_OK_PTR(link, "attach_struct_ops");
bpf_link__destroy(link);
tcp_ca_write_sk_pacing__destroy(skel);
}
void test_bpf_tcp_ca(void)
{
if (test__start_subtest("dctcp"))
@ -334,4 +351,6 @@ void test_bpf_tcp_ca(void)
test_dctcp_fallback();
if (test__start_subtest("rel_setsockopt"))
test_rel_setsockopt();
if (test__start_subtest("write_sk_pacing"))
test_write_sk_pacing();
}

60
tools/testing/selftests/bpf/progs/tcp_ca_write_sk_pacing.c Normal file
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@ -0,0 +1,60 @@
// SPDX-License-Identifier: GPL-2.0
#include "vmlinux.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
char _license[] SEC("license") = "GPL";
#define USEC_PER_SEC 1000000UL
#define min(a, b) ((a) < (b) ? (a) : (b))
static inline struct tcp_sock *tcp_sk(const struct sock *sk)
{
return (struct tcp_sock *)sk;
}
SEC("struct_ops/write_sk_pacing_init")
void BPF_PROG(write_sk_pacing_init, struct sock *sk)
{
#ifdef ENABLE_ATOMICS_TESTS
__sync_bool_compare_and_swap(&sk->sk_pacing_status, SK_PACING_NONE,
SK_PACING_NEEDED);
#else
sk->sk_pacing_status = SK_PACING_NEEDED;
#endif
}
SEC("struct_ops/write_sk_pacing_cong_control")
void BPF_PROG(write_sk_pacing_cong_control, struct sock *sk,
const struct rate_sample *rs)
{
const struct tcp_sock *tp = tcp_sk(sk);
unsigned long rate =
((tp->snd_cwnd * tp->mss_cache * USEC_PER_SEC) << 3) /
(tp->srtt_us ?: 1U << 3);
sk->sk_pacing_rate = min(rate, sk->sk_max_pacing_rate);
}
SEC("struct_ops/write_sk_pacing_ssthresh")
__u32 BPF_PROG(write_sk_pacing_ssthresh, struct sock *sk)
{
return tcp_sk(sk)->snd_ssthresh;
}
SEC("struct_ops/write_sk_pacing_undo_cwnd")
__u32 BPF_PROG(write_sk_pacing_undo_cwnd, struct sock *sk)
{
return tcp_sk(sk)->snd_cwnd;
}
SEC(".struct_ops")
struct tcp_congestion_ops write_sk_pacing = {
.init = (void *)write_sk_pacing_init,
.cong_control = (void *)write_sk_pacing_cong_control,
.ssthresh = (void *)write_sk_pacing_ssthresh,
.undo_cwnd = (void *)write_sk_pacing_undo_cwnd,
.name = "bpf_w_sk_pacing",
};