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* [PATCH bpf-next v6 1/2] bpf: support BPF_PROG_QUERY for progs attached to sockmap
@ 2022-01-19  1:40 Di Zhu
  2022-01-19  1:40 ` [PATCH bpf-next v6 2/2] selftests: bpf: test " Di Zhu
  2022-01-20 18:49 ` [PATCH bpf-next v6 1/2] bpf: support " Jakub Sitnicki
  0 siblings, 2 replies; 6+ messages in thread
From: Di Zhu @ 2022-01-19  1:40 UTC (permalink / raw)
  To: andrii.nakryiko, ast, davem, daniel, andrii, kafai,
	songliubraving, yhs, john.fastabend, kpsingh, jakub
  Cc: bpf, linux-kernel, zhudi2, luzhihao, rose.chen

Right now there is no way to query whether BPF programs are
attached to a sockmap or not.

we can use the standard interface in libbpf to query, such as:
bpf_prog_query(mapFd, BPF_SK_SKB_STREAM_PARSER, 0, NULL, ...);
the mapFd is the fd of sockmap.

Signed-off-by: Di Zhu <zhudi2@huawei.com>
Acked-by: Yonghong Song <yhs@fb.com>
---
 include/linux/bpf.h  |  9 ++++++
 kernel/bpf/syscall.c |  5 +++
 net/core/sock_map.c  | 77 ++++++++++++++++++++++++++++++++++++++++----
 3 files changed, 84 insertions(+), 7 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 6e947cd91152..c4ca14c9f838 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2071,6 +2071,9 @@ int bpf_prog_test_run_syscall(struct bpf_prog *prog,
 int sock_map_get_from_fd(const union bpf_attr *attr, struct bpf_prog *prog);
 int sock_map_prog_detach(const union bpf_attr *attr, enum bpf_prog_type ptype);
 int sock_map_update_elem_sys(struct bpf_map *map, void *key, void *value, u64 flags);
+int sock_map_bpf_prog_query(const union bpf_attr *attr,
+			    union bpf_attr __user *uattr);
+
 void sock_map_unhash(struct sock *sk);
 void sock_map_close(struct sock *sk, long timeout);
 #else
@@ -2124,6 +2127,12 @@ static inline int sock_map_update_elem_sys(struct bpf_map *map, void *key, void
 {
 	return -EOPNOTSUPP;
 }
+
+static inline int sock_map_bpf_prog_query(const union bpf_attr *attr,
+					  union bpf_attr __user *uattr)
+{
+	return -EINVAL;
+}
 #endif /* CONFIG_BPF_SYSCALL */
 #endif /* CONFIG_NET && CONFIG_BPF_SYSCALL */
 
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index fa4505f9b611..9e0631f091a6 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3318,6 +3318,11 @@ static int bpf_prog_query(const union bpf_attr *attr,
 	case BPF_FLOW_DISSECTOR:
 	case BPF_SK_LOOKUP:
 		return netns_bpf_prog_query(attr, uattr);
+	case BPF_SK_SKB_STREAM_PARSER:
+	case BPF_SK_SKB_STREAM_VERDICT:
+	case BPF_SK_MSG_VERDICT:
+	case BPF_SK_SKB_VERDICT:
+		return sock_map_bpf_prog_query(attr, uattr);
 	default:
 		return -EINVAL;
 	}
diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index 1827669eedd6..2d213c4011db 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -1416,38 +1416,50 @@ static struct sk_psock_progs *sock_map_progs(struct bpf_map *map)
 	return NULL;
 }
 
-static int sock_map_prog_update(struct bpf_map *map, struct bpf_prog *prog,
-				struct bpf_prog *old, u32 which)
+static int sock_map_prog_lookup(struct bpf_map *map, struct bpf_prog ***pprog,
+				u32 which)
 {
 	struct sk_psock_progs *progs = sock_map_progs(map);
-	struct bpf_prog **pprog;
 
 	if (!progs)
 		return -EOPNOTSUPP;
 
 	switch (which) {
 	case BPF_SK_MSG_VERDICT:
-		pprog = &progs->msg_parser;
+		*pprog = &progs->msg_parser;
 		break;
 #if IS_ENABLED(CONFIG_BPF_STREAM_PARSER)
 	case BPF_SK_SKB_STREAM_PARSER:
-		pprog = &progs->stream_parser;
+		*pprog = &progs->stream_parser;
 		break;
 #endif
 	case BPF_SK_SKB_STREAM_VERDICT:
 		if (progs->skb_verdict)
 			return -EBUSY;
-		pprog = &progs->stream_verdict;
+		*pprog = &progs->stream_verdict;
 		break;
 	case BPF_SK_SKB_VERDICT:
 		if (progs->stream_verdict)
 			return -EBUSY;
-		pprog = &progs->skb_verdict;
+		*pprog = &progs->skb_verdict;
 		break;
 	default:
 		return -EOPNOTSUPP;
 	}
 
+	return 0;
+}
+
+static int sock_map_prog_update(struct bpf_map *map, struct bpf_prog *prog,
+				struct bpf_prog *old, u32 which)
+{
+	struct bpf_prog **pprog;
+	int ret;
+
+	ret = sock_map_prog_lookup(map, &pprog, which);
+	if (ret)
+		return ret;
+
 	if (old)
 		return psock_replace_prog(pprog, prog, old);
 
@@ -1455,6 +1467,57 @@ static int sock_map_prog_update(struct bpf_map *map, struct bpf_prog *prog,
 	return 0;
 }
 
+int sock_map_bpf_prog_query(const union bpf_attr *attr,
+			    union bpf_attr __user *uattr)
+{
+	__u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids);
+	u32 prog_cnt = 0, flags = 0, ufd = attr->target_fd;
+	struct bpf_prog **pprog;
+	struct bpf_prog *prog;
+	struct bpf_map *map;
+	struct fd f;
+	u32 id = 0;
+	int ret;
+
+	if (attr->query.query_flags)
+		return -EINVAL;
+
+	f = fdget(ufd);
+	map = __bpf_map_get(f);
+	if (IS_ERR(map))
+		return PTR_ERR(map);
+
+	rcu_read_lock();
+
+	ret = sock_map_prog_lookup(map, &pprog, attr->query.attach_type);
+	if (ret)
+		goto end;
+
+	prog = *pprog;
+	prog_cnt = !prog ? 0 : 1;
+
+	if (!attr->query.prog_cnt || !prog_ids || !prog_cnt)
+		goto end;
+
+	/* we do not hold the refcnt, the bpf prog may be released
+	 * asynchronously and the id would be set to 0.
+	 */
+	id = data_race(prog->aux->id);
+	if (id == 0)
+		prog_cnt = 0;
+
+end:
+	rcu_read_unlock();
+
+	if (copy_to_user(&uattr->query.attach_flags, &flags, sizeof(flags)) ||
+	    (id != 0 && copy_to_user(prog_ids, &id, sizeof(u32))) ||
+	    copy_to_user(&uattr->query.prog_cnt, &prog_cnt, sizeof(prog_cnt)))
+		ret = -EFAULT;
+
+	fdput(f);
+	return ret;
+}
+
 static void sock_map_unlink(struct sock *sk, struct sk_psock_link *link)
 {
 	switch (link->map->map_type) {
-- 
2.27.0


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* Re: [PATCH bpf-next v6 2/2] selftests: bpf: test BPF_PROG_QUERY for progs attached to sockmap
@ 2022-01-21  6:19 zhudi (E)
  0 siblings, 0 replies; 6+ messages in thread
From: zhudi (E) @ 2022-01-21  6:19 UTC (permalink / raw)
  To: Alexei Starovoitov
  Cc: Andrii Nakryiko, Alexei Starovoitov, David S. Miller,
	Daniel Borkmann, Andrii Nakryiko, Martin KaFai Lau, Song Liu,
	Yonghong Song, John Fastabend, KP Singh, Jakub Sitnicki, bpf,
	LKML, Luzhihao (luzhihao, Euler), Chenxiang (EulerOS)

> > Add test for querying progs attached to sockmap. we use an existing
> > libbpf query interface to query prog cnt before and after progs
> > attaching to sockmap and check whether the queried prog id is right.
> >
> > Signed-off-by: Di Zhu <zhudi2@huawei.com>
> > Acked-by: Yonghong Song <yhs@fb.com>
> > ---
> >  .../selftests/bpf/prog_tests/sockmap_basic.c  | 66 +++++++++++++++++++
> >  .../bpf/progs/test_sockmap_progs_query.c      | 24 +++++++
> >  2 files changed, 90 insertions(+)
> >  create mode 100644
> tools/testing/selftests/bpf/progs/test_sockmap_progs_query.c
> >
> > diff --git a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
> b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
> > index 85db0f4cdd95..1ab57cdc4ae4 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
> > @@ -8,6 +8,7 @@
> >  #include "test_sockmap_update.skel.h"
> >  #include "test_sockmap_invalid_update.skel.h"
> >  #include "test_sockmap_skb_verdict_attach.skel.h"
> > +#include "test_sockmap_progs_query.skel.h"
> >  #include "bpf_iter_sockmap.skel.h"
> >
> >  #define TCP_REPAIR             19      /* TCP sock is under repair
> right now */
> > @@ -315,6 +316,63 @@ static void test_sockmap_skb_verdict_attach(enum
> bpf_attach_type first,
> >         test_sockmap_skb_verdict_attach__destroy(skel);
> >  }
> >
> > +static __u32 query_prog_id(int prog_fd)
> > +{
> > +       struct bpf_prog_info info = {};
> > +       __u32 info_len = sizeof(info);
> > +       int err;
> > +
> > +       err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
> > +       if (!ASSERT_OK(err, "bpf_obj_get_info_by_fd") ||
> > +           !ASSERT_EQ(info_len, sizeof(info), "bpf_obj_get_info_by_fd"))
> > +               return 0;
> > +
> > +       return info.id;
> > +}
> > +
> > +static void test_sockmap_progs_query(enum bpf_attach_type attach_type)
> > +{
> > +       struct test_sockmap_progs_query *skel;
> > +       int err, map_fd, verdict_fd, duration = 0;
> 
> The 'duration' is unused.
> You should have seen a warning while compiling the selftests?
> 
> Anyway. I've fixed it while applying.

Thank you. I'll be more careful next time.


^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-01-21  6:19 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2022-01-19  1:40 [PATCH bpf-next v6 1/2] bpf: support BPF_PROG_QUERY for progs attached to sockmap Di Zhu
2022-01-19  1:40 ` [PATCH bpf-next v6 2/2] selftests: bpf: test " Di Zhu
2022-01-20 18:49   ` Jakub Sitnicki
2022-01-21  5:36   ` Alexei Starovoitov
2022-01-20 18:49 ` [PATCH bpf-next v6 1/2] bpf: support " Jakub Sitnicki
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2022-01-21  6:19 [PATCH bpf-next v6 2/2] selftests: bpf: test " zhudi (E)

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