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Message-ID: <c929dced-e70e-4f49-b812-026b2677bfd9@linux.dev>
Date: Thu, 9 May 2024 12:17:40 -0700
From: Martin KaFai Lau <martin.lau@...ux.dev>
To: Abhishek Chauhan <quic_abchauha@...cinc.com>
Cc: "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org, Andrew Halaney <ahalaney@...hat.com>,
Willem de Bruijn <willemdebruijn.kernel@...il.com>,
Martin KaFai Lau <martin.lau@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>, bpf <bpf@...r.kernel.org>,
kernel@...cinc.com
Subject: Re: [RFC PATCH bpf-next v7 3/3] selftests/bpf: Handle forwarding of
UDP CLOCK_TAI packets
On 5/8/24 2:58 PM, Abhishek Chauhan wrote:
> With changes in the design to forward CLOCK_TAI in the skbuff
> framework, existing selftest framework needs modification
> to handle forwarding of UDP packets with CLOCK_TAI as clockid.
The set lgtm. I have a few final nits on the test.
>
> Link: https://lore.kernel.org/netdev/bc037db4-58bb-4861-ac31-a361a93841d3@linux.dev/
> Signed-off-by: Abhishek Chauhan <quic_abchauha@...cinc.com>
> ---
> Changes since v7
> - Fixed issues in the ctx_rewrite.c
> with respect to dissembly in both
> .read and .write
>
> Changes since v6
> - Moved all the selftest to another patch
>
> Changes since v1 - v5
> - Patch was not present
>
> tools/include/uapi/linux/bpf.h | 15 ++++---
> .../selftests/bpf/prog_tests/ctx_rewrite.c | 10 +++--
> .../selftests/bpf/prog_tests/tc_redirect.c | 3 --
> .../selftests/bpf/progs/test_tc_dtime.c | 39 +++++++++----------
> 4 files changed, 34 insertions(+), 33 deletions(-)
>
> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index 90706a47f6ff..25ea393cf084 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
nit. Please move this bpf.h sync changes to patch 2 where the uapi changes happen.
> @@ -6207,12 +6207,17 @@ union { \
> __u64 :64; \
> } __attribute__((aligned(8)))
>
> +/* The enum used in skb->tstamp_type. It specifies the clock type
> + * of the time stored in the skb->tstamp.
> + */
> enum {
> - BPF_SKB_TSTAMP_UNSPEC,
> - BPF_SKB_TSTAMP_DELIVERY_MONO, /* tstamp has mono delivery time */
> - /* For any BPF_SKB_TSTAMP_* that the bpf prog cannot handle,
> - * the bpf prog should handle it like BPF_SKB_TSTAMP_UNSPEC
> - * and try to deduce it by ingress, egress or skb->sk->sk_clockid.
> + BPF_SKB_TSTAMP_UNSPEC = 0, /* DEPRECATED */
> + BPF_SKB_TSTAMP_DELIVERY_MONO = 1, /* DEPRECATED */
> + BPF_SKB_CLOCK_REALTIME = 0,
> + BPF_SKB_CLOCK_MONOTONIC = 1,
> + BPF_SKB_CLOCK_TAI = 2,
> + /* For any future BPF_SKB_CLOCK_* that the bpf prog cannot handle,
> + * the bpf prog can try to deduce it by ingress/egress/skb->sk->sk_clockid.
> */
> };
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/ctx_rewrite.c b/tools/testing/selftests/bpf/prog_tests/ctx_rewrite.c
> index 3b7c57fe55a5..08b6391f2f56 100644
> --- a/tools/testing/selftests/bpf/prog_tests/ctx_rewrite.c
> +++ b/tools/testing/selftests/bpf/prog_tests/ctx_rewrite.c
> @@ -69,15 +69,17 @@ static struct test_case test_cases[] = {
> {
> N(SCHED_CLS, struct __sk_buff, tstamp),
> .read = "r11 = *(u8 *)($ctx + sk_buff::__mono_tc_offset);"
> - "w11 &= 3;"
> - "if w11 != 0x3 goto pc+2;"
> + "if w11 & 0x4 goto pc+1;"
> + "goto pc+4;"
> + "if w11 & 0x3 goto pc+1;"
> + "goto pc+2;"
> "$dst = 0;"
> "goto pc+1;"
> "$dst = *(u64 *)($ctx + sk_buff::tstamp);",
> .write = "r11 = *(u8 *)($ctx + sk_buff::__mono_tc_offset);"
> - "if w11 & 0x2 goto pc+1;"
> + "if w11 & 0x4 goto pc+1;"
> "goto pc+2;"
> - "w11 &= -2;"
> + "w11 &= -4;"
> "*(u8 *)($ctx + sk_buff::__mono_tc_offset) = r11;"
> "*(u64 *)($ctx + sk_buff::tstamp) = $src;",
> },
> diff --git a/tools/testing/selftests/bpf/prog_tests/tc_redirect.c b/tools/testing/selftests/bpf/prog_tests/tc_redirect.c
> index b1073d36d77a..327d51f59142 100644
> --- a/tools/testing/selftests/bpf/prog_tests/tc_redirect.c
> +++ b/tools/testing/selftests/bpf/prog_tests/tc_redirect.c
> @@ -890,9 +890,6 @@ static void test_udp_dtime(struct test_tc_dtime *skel, int family, bool bpf_fwd)
>
> ASSERT_EQ(dtimes[INGRESS_FWDNS_P100], 0,
> dtime_cnt_str(t, INGRESS_FWDNS_P100));
> - /* non mono delivery time is not forwarded */
> - ASSERT_EQ(dtimes[INGRESS_FWDNS_P101], 0,
> - dtime_cnt_str(t, INGRESS_FWDNS_P101));
> for (i = EGRESS_FWDNS_P100; i < SET_DTIME; i++)
> ASSERT_GT(dtimes[i], 0, dtime_cnt_str(t, i));
>
> diff --git a/tools/testing/selftests/bpf/progs/test_tc_dtime.c b/tools/testing/selftests/bpf/progs/test_tc_dtime.c
> index 74ec09f040b7..21f5be202e4b 100644
> --- a/tools/testing/selftests/bpf/progs/test_tc_dtime.c
> +++ b/tools/testing/selftests/bpf/progs/test_tc_dtime.c
> @@ -222,13 +222,19 @@ int egress_host(struct __sk_buff *skb)
> return TC_ACT_OK;
>
> if (skb_proto(skb_type) == IPPROTO_TCP) {
> - if (skb->tstamp_type == BPF_SKB_TSTAMP_DELIVERY_MONO &&
> + if (skb->tstamp_type == BPF_SKB_CLOCK_MONOTONIC &&
> + skb->tstamp)
> + inc_dtimes(EGRESS_ENDHOST);
> + else
> + inc_errs(EGRESS_ENDHOST);
> + } else if (skb_proto(skb_type) == IPPROTO_UDP) {
> + if (skb->tstamp_type == BPF_SKB_CLOCK_TAI &&
> skb->tstamp)
> inc_dtimes(EGRESS_ENDHOST);
> else
> inc_errs(EGRESS_ENDHOST);
> } else {
> - if (skb->tstamp_type == BPF_SKB_TSTAMP_UNSPEC &&
> + if (skb->tstamp_type == BPF_SKB_CLOCK_REALTIME &&
> skb->tstamp)
Since the UDP+TAI can be handled properly in the above "else if" case now, I
would like to further tighten the bolt on detecting the non-zero REALTIME
skb->tstamp here since it should not happen at egress. Something like:
} else {
if (skb->tstamp_type == BPF_SKB_CLOCK_REALTIME &&
skb->tstamp)
inc_errs(EGRESS_ENDHOST);
}
I ran the test (w or w/o the above inc_errs changes) in a loop and it
consistently passes now.
Other than the above small nits, in the next re-spin, please remove the RFC tag
and you can carry my reviewed-by to all 3 patches. Thanks.
Reviewed-by: Martin KaFai Lau <martin.lau@...nel.org>
> inc_dtimes(EGRESS_ENDHOST);
> else
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