Re: [RFC PATCH bpf-next v7 3/3] selftests/bpf: Handle forwarding of UDP CLOCK_TAI packets
From: Martin KaFai Lau
Date: Thu May 09 2024 - 15:19:15 EST
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@xxxxxxxxx/
Signed-off-by: Abhishek Chauhan <quic_abchauha@xxxxxxxxxxx>
---
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@xxxxxxxxxx>
inc_dtimes(EGRESS_ENDHOST);
else