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authorKaFai Wan <kafai.wan@linux.dev>2026-04-21 18:58:04 +0300
committerMartin KaFai Lau <martin.lau@kernel.org>2026-04-22 22:59:49 +0300
commit2c7e33f1fc2e75fcfb4aa5d840bcd2e8b53c1847 (patch)
treea34a7ef5dbb92baf3780719fb96fc4dca9db02f1
parent52b6b5334924d8f083a2abe8edeface9206e13ee (diff)
downloadlinux-2c7e33f1fc2e75fcfb4aa5d840bcd2e8b53c1847.tar.xz
selftests/bpf: Verify bpf-tcp-cc rejects TCP_NODELAY
Add a bpf_tcp_ca selftest for the TCP_NODELAY restriction in bpf-tcp-cc. Update bpf_cubic to exercise init() and cwnd_event_tx_start(), and check that both callbacks reject bpf_setsockopt(TCP_NODELAY) with -EOPNOTSUPP. Signed-off-by: KaFai Wan <kafai.wan@linux.dev> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://patch.msgid.link/20260421155804.135786-5-kafai.wan@linux.dev
-rw-r--r--tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c4
-rw-r--r--tools/testing/selftests/bpf/progs/bpf_cubic.c14
2 files changed, 18 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
index f829b6f09bc9..fe30181e6336 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
@@ -112,6 +112,10 @@ static void test_cubic(void)
ASSERT_EQ(cubic_skel->bss->bpf_cubic_acked_called, 1, "pkts_acked called");
+ ASSERT_TRUE(cubic_skel->bss->nodelay_init_reject, "init reject nodelay option");
+ ASSERT_TRUE(cubic_skel->bss->nodelay_cwnd_event_tx_start_reject,
+ "cwnd_event_tx_start reject nodelay option");
+
bpf_link__destroy(link);
bpf_cubic__destroy(cubic_skel);
}
diff --git a/tools/testing/selftests/bpf/progs/bpf_cubic.c b/tools/testing/selftests/bpf/progs/bpf_cubic.c
index ce18a4db813f..ebd5a1e69f56 100644
--- a/tools/testing/selftests/bpf/progs/bpf_cubic.c
+++ b/tools/testing/selftests/bpf/progs/bpf_cubic.c
@@ -16,6 +16,7 @@
#include "bpf_tracing_net.h"
#include <bpf/bpf_tracing.h>
+#include <errno.h>
char _license[] SEC("license") = "GPL";
@@ -170,10 +171,18 @@ static void bictcp_hystart_reset(struct sock *sk)
ca->sample_cnt = 0;
}
+bool nodelay_init_reject = false;
+bool nodelay_cwnd_event_tx_start_reject = false;
+
SEC("struct_ops")
void BPF_PROG(bpf_cubic_init, struct sock *sk)
{
struct bpf_bictcp *ca = inet_csk_ca(sk);
+ int true_val = 1, ret;
+
+ ret = bpf_setsockopt(sk, SOL_TCP, TCP_NODELAY, &true_val, sizeof(true_val));
+ if (ret == -EOPNOTSUPP)
+ nodelay_init_reject = true;
bictcp_reset(ca);
@@ -189,8 +198,13 @@ void BPF_PROG(bpf_cubic_cwnd_event_tx_start, struct sock *sk)
{
struct bpf_bictcp *ca = inet_csk_ca(sk);
__u32 now = tcp_jiffies32;
+ int true_val = 1, ret;
__s32 delta;
+ ret = bpf_setsockopt(sk, SOL_TCP, TCP_NODELAY, &true_val, sizeof(true_val));
+ if (ret == -EOPNOTSUPP)
+ nodelay_cwnd_event_tx_start_reject = true;
+
delta = now - tcp_sk(sk)->lsndtime;
/* We were application limited (idle) for a while.