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selftests/bpf: Test an incomplete BPF CC

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Test whether a TCP CC implemented in BPF providing neither cong_avoid()
nor cong_control() is correctly rejected. This check solely depends on
tcp_register_congestion_control() now, which is invoked during
bpf_map__attach_struct_ops().

Signed-off-by: Jörn-Thorben Hinz <jthinz@mailbox.tu-berlin.de>
Link: https://lore.kernel.org/r/20220622191227.898118-5-jthinz@mailbox.tu-berlin.de
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Jörn-Thorben Hinz 2022-06-22 21:12:26 +02:00 committed by Alexei Starovoitov
parent 6e945d57cc
commit 0735627d78
2 changed files with 57 additions and 0 deletions
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22
tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
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@ -10,6 +10,7 @@
#include "bpf_tcp_nogpl.skel.h"
#include "bpf_dctcp_release.skel.h"
#include "tcp_ca_write_sk_pacing.skel.h"
#include "tcp_ca_incompl_cong_ops.skel.h"
#ifndef ENOTSUPP
#define ENOTSUPP 524
@ -339,6 +340,25 @@ static void test_write_sk_pacing(void)
tcp_ca_write_sk_pacing__destroy(skel);
}
static void test_incompl_cong_ops(void)
{
struct tcp_ca_incompl_cong_ops *skel;
struct bpf_link *link;
skel = tcp_ca_incompl_cong_ops__open_and_load();
if (!ASSERT_OK_PTR(skel, "open_and_load"))
return;
/* That cong_avoid() and cong_control() are missing is only reported at
* this point:
*/
link = bpf_map__attach_struct_ops(skel->maps.incompl_cong_ops);
ASSERT_ERR_PTR(link, "attach_struct_ops");
bpf_link__destroy(link);
tcp_ca_incompl_cong_ops__destroy(skel);
}
void test_bpf_tcp_ca(void)
{
if (test__start_subtest("dctcp"))
@ -353,4 +373,6 @@ void test_bpf_tcp_ca(void)
test_rel_setsockopt();
if (test__start_subtest("write_sk_pacing"))
test_write_sk_pacing();
if (test__start_subtest("incompl_cong_ops"))
test_incompl_cong_ops();
}

35
tools/testing/selftests/bpf/progs/tcp_ca_incompl_cong_ops.c Normal file
View File

@ -0,0 +1,35 @@
// SPDX-License-Identifier: GPL-2.0
#include "vmlinux.h"
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
char _license[] SEC("license") = "GPL";
static inline struct tcp_sock *tcp_sk(const struct sock *sk)
{
return (struct tcp_sock *)sk;
}
SEC("struct_ops/incompl_cong_ops_ssthresh")
__u32 BPF_PROG(incompl_cong_ops_ssthresh, struct sock *sk)
{
return tcp_sk(sk)->snd_ssthresh;
}
SEC("struct_ops/incompl_cong_ops_undo_cwnd")
__u32 BPF_PROG(incompl_cong_ops_undo_cwnd, struct sock *sk)
{
return tcp_sk(sk)->snd_cwnd;
}
SEC(".struct_ops")
struct tcp_congestion_ops incompl_cong_ops = {
/* Intentionally leaving out any of the required cong_avoid() and
* cong_control() here.
*/
.ssthresh = (void *)incompl_cong_ops_ssthresh,
.undo_cwnd = (void *)incompl_cong_ops_undo_cwnd,
.name = "bpf_incompl_ops",
};