From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-177.mta1.migadu.com (out-177.mta1.migadu.com [95.215.58.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 40DA0278E63 for ; Wed, 12 Nov 2025 23:24:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.177 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762989854; cv=none; b=r7QI+J0Xve1C4D6Na4cX/PhAuGqsozVWyrgJYIUwHxLfZ0MwAQTssClHMHRU8zi/SCFC5Jz8JbiTDfMQJCzi6bl9noBs7lKEXpVbeG/4kus/iQs2U1c1mudBhwjczpOZdzk3C1PG4Zflu8xeTDoH0/gikCZB6vtTi8Zsx63iGS8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762989854; c=relaxed/simple; bh=l9lN7lp0++mmIOFkRAkbNQ9oR6dF0BER0pTD69UpuSg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OztVC88+tfutz7+A63ve6hBWVXstp9CwefXZ//PdUjaGeihPdBIVGbpQGk8Niiv22nygp7M7q56fVmbBqwa8tTtwLfYgMFsz9FhtNiRZbxBAncbFAbJwdAx6xMv7sJiTUSco5qkOJ0RvruQR8K2oOiNnOPJCm2tez8bLucolmfE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=pcZguUuC; arc=none smtp.client-ip=95.215.58.177 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="pcZguUuC" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1762989849; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xer3eO9KF7g9JfEkIncqpMpp6r9qiuGWx5sYuf4J0mk=; b=pcZguUuCmnCo9sjcj2nSUeqCeMGgrRSNMfGk2qc9M34V9qRimzdwQpcYYZeyuln5yVeOjK gPHyjbM5PWWOs04G6LrRCKkcgsB4QV/LCk0PluLcg4n6UFePml5z+WJvTqCXcaurttmE2Q lIff3nWb9j56yIwm0XnQqsMjoWS7M7E= From: Martin KaFai Lau To: bpf@vger.kernel.org Cc: 'Alexei Starovoitov ' , 'Andrii Nakryiko ' , 'Daniel Borkmann ' , netdev@vger.kernel.org Subject: [PATCH bpf-next 2/2] selftests/bpf: Test bpf_skb_check_mtu(BPF_MTU_CHK_SEGS) when transport_header is not set Date: Wed, 12 Nov 2025 15:23:31 -0800 Message-ID: <20251112232331.1566074-2-martin.lau@linux.dev> In-Reply-To: <20251112232331.1566074-1-martin.lau@linux.dev> References: <20251112232331.1566074-1-martin.lau@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT From: Martin KaFai Lau Add a test to check that bpf_skb_check_mtu(BPF_MTU_CHK_SEGS) is rejected (-EINVAL) if skb->transport_header is not set. The test needs to lower the MTU of the loopback device. Thus, take this opportunity to run the test in a netns by adding "ns_" to the test name. The "serial_" prefix can then be removed. Signed-off-by: Martin KaFai Lau --- .../selftests/bpf/prog_tests/check_mtu.c | 23 ++++++++++++++++++- .../selftests/bpf/progs/test_check_mtu.c | 12 ++++++++++ 2 files changed, 34 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/prog_tests/check_mtu.c b/tools/testing/selftests/bpf/prog_tests/check_mtu.c index 2a9a30650350..65b4512967e7 100644 --- a/tools/testing/selftests/bpf/prog_tests/check_mtu.c +++ b/tools/testing/selftests/bpf/prog_tests/check_mtu.c @@ -153,6 +153,26 @@ static void test_check_mtu_run_tc(struct test_check_mtu *skel, ASSERT_EQ(mtu_result, mtu_expect, "MTU-compare-user"); } +static void test_chk_segs_flag(struct test_check_mtu *skel, __u32 mtu) +{ + int err, prog_fd = bpf_program__fd(skel->progs.tc_chk_segs_flag); + struct __sk_buff skb = { + .gso_size = 10, + }; + LIBBPF_OPTS(bpf_test_run_opts, topts, + .data_in = &pkt_v4, + .data_size_in = sizeof(pkt_v4), + .ctx_in = &skb, + .ctx_size_in = sizeof(skb), + ); + + /* Lower the mtu to test the BPF_MTU_CHK_SEGS */ + SYS_NOFAIL("ip link set dev lo mtu 10"); + err = bpf_prog_test_run_opts(prog_fd, &topts); + SYS_NOFAIL("ip link set dev lo mtu %u", mtu); + ASSERT_OK(err, "test_run"); + ASSERT_EQ(topts.retval, BPF_OK, "retval"); +} static void test_check_mtu_tc(__u32 mtu, __u32 ifindex) { @@ -177,11 +197,12 @@ static void test_check_mtu_tc(__u32 mtu, __u32 ifindex) test_check_mtu_run_tc(skel, skel->progs.tc_minus_delta, mtu); test_check_mtu_run_tc(skel, skel->progs.tc_input_len, mtu); test_check_mtu_run_tc(skel, skel->progs.tc_input_len_exceed, mtu); + test_chk_segs_flag(skel, mtu); cleanup: test_check_mtu__destroy(skel); } -void serial_test_check_mtu(void) +void test_ns_check_mtu(void) { int mtu_lo; diff --git a/tools/testing/selftests/bpf/progs/test_check_mtu.c b/tools/testing/selftests/bpf/progs/test_check_mtu.c index 2ec1de11a3ae..7b6b2b342c1d 100644 --- a/tools/testing/selftests/bpf/progs/test_check_mtu.c +++ b/tools/testing/selftests/bpf/progs/test_check_mtu.c @@ -7,6 +7,7 @@ #include #include +#include char _license[] SEC("license") = "GPL"; @@ -288,3 +289,14 @@ int tc_input_len_exceed(struct __sk_buff *ctx) global_bpf_mtu_xdp = mtu_len; return retval; } + +SEC("tc") +int tc_chk_segs_flag(struct __sk_buff *ctx) +{ + __u32 mtu_len = 0; + int err; + + err = bpf_check_mtu(ctx, GLOBAL_USER_IFINDEX, &mtu_len, 0, BPF_MTU_CHK_SEGS); + + return err == -EINVAL ? BPF_OK : BPF_DROP; +} -- 2.47.3