[PATCH bpf-next v2 1/2] bpf: expose __sk_buff wire_len/gso_segs to BPF_PROG_TEST_RUN

[PATCH bpf-next v2 1/2] bpf: expose __sk_buff wire_len/gso_segs to BPF_PROG_TEST_RUN

[Stanislav Fomichev]

wire_len should not be less than real len and is capped by GSO_MAX_SIZE.
gso_segs is capped by GSO_MAX_SEGS.

v2:
* set wire_len to skb->len when passed wire_len is 0 (Alexei Starovoitov)

Cc: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 net/bpf/test_run.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 85c8cbbada92..f23707075f26 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -263,8 +263,10 @@ static int convert___skb_to_skb(struct sk_buff *skb, struct __sk_buff *__skb)
 		return -EINVAL;
 
 	/* tstamp is allowed */
+	/* wire_len is allowed */
+	/* gso_segs is allowed */
 
-	if (!range_is_zero(__skb, offsetofend(struct __sk_buff, tstamp),
+	if (!range_is_zero(__skb, offsetofend(struct __sk_buff, gso_segs),
 			   sizeof(struct __sk_buff)))
 		return -EINVAL;
 
@@ -272,6 +274,19 @@ static int convert___skb_to_skb(struct sk_buff *skb, struct __sk_buff *__skb)
 	skb->tstamp = __skb->tstamp;
 	memcpy(&cb->data, __skb->cb, QDISC_CB_PRIV_LEN);
 
+	if (__skb->wire_len == 0) {
+		cb->pkt_len = skb->len;
+	} else {
+		if (__skb->wire_len < skb->len ||
+		    __skb->wire_len > GSO_MAX_SIZE)
+			return -EINVAL;
+		cb->pkt_len = __skb->wire_len;
+	}
+
+	if (__skb->gso_segs > GSO_MAX_SEGS)
+		return -EINVAL;
+	skb_shinfo(skb)->gso_segs = __skb->gso_segs;
+
 	return 0;
 }
 
@@ -285,6 +300,8 @@ static void convert_skb_to___skb(struct sk_buff *skb, struct __sk_buff *__skb)
 	__skb->priority = skb->priority;
 	__skb->tstamp = skb->tstamp;
 	memcpy(__skb->cb, &cb->data, QDISC_CB_PRIV_LEN);
+	__skb->wire_len = cb->pkt_len;
+	__skb->gso_segs = skb_shinfo(skb)->gso_segs;
 }
 
 int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
-- 
2.24.1.735.g03f4e72817-goog

[PATCH bpf-next v2 2/2] selftests/bpf: test wire_len/gso_segs in BPF_PROG_TEST_RUN

[Stanislav Fomichev]

Make sure we can pass arbitrary data in wire_len/gso_segs.

Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
---
 tools/testing/selftests/bpf/prog_tests/skb_ctx.c | 2 ++
 tools/testing/selftests/bpf/progs/test_skb_ctx.c | 5 +++++
 2 files changed, 7 insertions(+)

diff --git a/tools/testing/selftests/bpf/prog_tests/skb_ctx.c b/tools/testing/selftests/bpf/prog_tests/skb_ctx.c
index a2eb8db8dafb..edf5e8c7d400 100644
--- a/tools/testing/selftests/bpf/prog_tests/skb_ctx.c
+++ b/tools/testing/selftests/bpf/prog_tests/skb_ctx.c
@@ -11,6 +11,8 @@ void test_skb_ctx(void)
 		.cb[4] = 5,
 		.priority = 6,
 		.tstamp = 7,
+		.wire_len = 100,
+		.gso_segs = 8,
 	};
 	struct bpf_prog_test_run_attr tattr = {
 		.data_in = &pkt_v4,
diff --git a/tools/testing/selftests/bpf/progs/test_skb_ctx.c b/tools/testing/selftests/bpf/progs/test_skb_ctx.c
index 2a9f4c736ebc..534fbf9a7344 100644
--- a/tools/testing/selftests/bpf/progs/test_skb_ctx.c
+++ b/tools/testing/selftests/bpf/progs/test_skb_ctx.c
@@ -18,5 +18,10 @@ int process(struct __sk_buff *skb)
 	skb->priority++;
 	skb->tstamp++;
 
+	if (skb->wire_len != 100)
+		return 1;
+	if (skb->gso_segs != 8)
+		return 1;
+
 	return 0;
 }
-- 
2.24.1.735.g03f4e72817-goog

Re: [PATCH bpf-next v2 1/2] bpf: expose __sk_buff wire_len/gso_segs to BPF_PROG_TEST_RUN

[Alexei Starovoitov]

On Fri, Dec 13, 2019 at 2:30 PM Stanislav Fomichev <sdf@google.com> wrote:
>
> wire_len should not be less than real len and is capped by GSO_MAX_SIZE.
> gso_segs is capped by GSO_MAX_SEGS.
>
> v2:
> * set wire_len to skb->len when passed wire_len is 0 (Alexei Starovoitov)
>
> Cc: Martin KaFai Lau <kafai@fb.com>
> Signed-off-by: Stanislav Fomichev <sdf@google.com>

Now works. Applied.