Commit 3411c5b6 authored by Martin KaFai Lau's avatar Martin KaFai Lau Committed by Alexei Starovoitov
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selftests/bpf: Check -EBUSY for the recurred bpf_setsockopt(TCP_CONGESTION) 



This patch changes the bpf_dctcp test to ensure the recurred
bpf_setsockopt(TCP_CONGESTION) returns -EBUSY.

Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220929070407.965581-6-martin.lau@linux.dev


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 061ff040

tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c

+4 −0
Original line number Diff line number Diff line
@@ -290,6 +290,10 @@ static void test_dctcp_fallback(void) 
		goto done;

	ASSERT_STREQ(dctcp_skel->bss->cc_res, "cubic", "cc_res");

	ASSERT_EQ(dctcp_skel->bss->tcp_cdg_res, -ENOTSUPP, "tcp_cdg_res");

	/* All setsockopt(TCP_CONGESTION) in the recurred

	 * bpf_dctcp->init() should fail with -EBUSY.

	 */

	ASSERT_EQ(dctcp_skel->bss->ebusy_cnt, 3, "ebusy_cnt");



	err = getsockopt(srv_fd, SOL_TCP, TCP_CONGESTION, srv_cc, &cc_len);

	if (!ASSERT_OK(err, "getsockopt(srv_fd, TCP_CONGESTION)"))

tools/testing/selftests/bpf/progs/bpf_dctcp.c

+17 −8
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
#include <linux/types.h>

#include <linux/stddef.h>

#include <linux/tcp.h>

#include <errno.h>

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>

#include "bpf_tcp_helpers.h"
@@ -23,6 +24,7 @@ const char tcp_cdg[] = "cdg"; 
char cc_res[TCP_CA_NAME_MAX];

int tcp_cdg_res = 0;

int stg_result = 0;

int ebusy_cnt = 0;



struct {

	__uint(type, BPF_MAP_TYPE_SK_STORAGE);
@@ -64,16 +66,23 @@ void BPF_PROG(dctcp_init, struct sock *sk) 


	if (!(tp->ecn_flags & TCP_ECN_OK) && fallback[0]) {

		/* Switch to fallback */

		bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION,

			       (void *)fallback, sizeof(fallback));

		/* Switch back to myself which the bpf trampoline

		 * stopped calling dctcp_init recursively.

		if (bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION,

				   (void *)fallback, sizeof(fallback)) == -EBUSY)

			ebusy_cnt++;



		/* Switch back to myself and the recurred dctcp_init()

		 * will get -EBUSY for all bpf_setsockopt(TCP_CONGESTION),

		 * except the last "cdg" one.

		 */

		bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION,

			       (void *)bpf_dctcp, sizeof(bpf_dctcp));

		if (bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION,

				   (void *)bpf_dctcp, sizeof(bpf_dctcp)) == -EBUSY)

			ebusy_cnt++;



		/* Switch back to fallback */

		bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION,

			       (void *)fallback, sizeof(fallback));

		if (bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION,

				   (void *)fallback, sizeof(fallback)) == -EBUSY)

			ebusy_cnt++;



		/* Expecting -ENOTSUPP for tcp_cdg_res */

		tcp_cdg_res = bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION,

					     (void *)tcp_cdg, sizeof(tcp_cdg));