* [PATCH bpf 1/2] libbpf: Fix bpf_get_link_xdp_id flags handling
2020-04-07 5:09 [PATCH bpf 0/2] libbpf: Fix bpf_get_link_xdp_id flags handling Andrey Ignatov
@ 2020-04-07 5:09 ` Andrey Ignatov
2020-04-07 9:04 ` Toke Høiland-Jørgensen
2020-04-07 5:09 ` [PATCH bpf 2/2] selftests/bpf: Add test for bpf_get_link_xdp_id Andrey Ignatov
2020-04-07 23:44 ` [PATCH bpf 0/2] libbpf: Fix bpf_get_link_xdp_id flags handling Daniel Borkmann
2 siblings, 1 reply; 5+ messages in thread
From: Andrey Ignatov @ 2020-04-07 5:09 UTC (permalink / raw)
To: bpf; +Cc: Andrey Ignatov, ast, daniel, kernel-team, toke
Currently if one of XDP_FLAGS_{DRV,HW,SKB}_MODE flags is passed to
bpf_get_link_xdp_id() and there is a single XDP program attached to
ifindex, that program's id will be returned by bpf_get_link_xdp_id() in
prog_id argument no matter what mode the program is attached in, i.e.
flags argument is not taken into account.
For example, if there is a single program attached with
XDP_FLAGS_SKB_MODE but user calls bpf_get_link_xdp_id() with flags =
XDP_FLAGS_DRV_MODE, that skb program will be returned.
Fix it by returning info->prog_id only if user didn't specify flags. If
flags is specified then return corresponding mode-specific-field from
struct xdp_link_info.
The initial error was introduced in commit 50db9f073188 ("libbpf: Add a
support for getting xdp prog id on ifindex") and then refactored in
473f4e133a12 so 473f4e133a12 is used in the Fixes tag.
Fixes: 473f4e133a12 ("libbpf: Add bpf_get_link_xdp_info() function to get more XDP information")
Signed-off-by: Andrey Ignatov <rdna@fb.com>
---
tools/lib/bpf/netlink.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c
index 18b5319025e1..f5732d35930d 100644
--- a/tools/lib/bpf/netlink.c
+++ b/tools/lib/bpf/netlink.c
@@ -321,7 +321,7 @@ int bpf_get_link_xdp_info(int ifindex, struct xdp_link_info *info,
static __u32 get_xdp_id(struct xdp_link_info *info, __u32 flags)
{
- if (info->attach_mode != XDP_ATTACHED_MULTI)
+ if (info->attach_mode != XDP_ATTACHED_MULTI && !flags)
return info->prog_id;
if (flags & XDP_FLAGS_DRV_MODE)
return info->drv_prog_id;
--
2.24.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH bpf 2/2] selftests/bpf: Add test for bpf_get_link_xdp_id
2020-04-07 5:09 [PATCH bpf 0/2] libbpf: Fix bpf_get_link_xdp_id flags handling Andrey Ignatov
2020-04-07 5:09 ` [PATCH bpf 1/2] " Andrey Ignatov
@ 2020-04-07 5:09 ` Andrey Ignatov
2020-04-07 23:44 ` [PATCH bpf 0/2] libbpf: Fix bpf_get_link_xdp_id flags handling Daniel Borkmann
2 siblings, 0 replies; 5+ messages in thread
From: Andrey Ignatov @ 2020-04-07 5:09 UTC (permalink / raw)
To: bpf; +Cc: Andrey Ignatov, ast, daniel, kernel-team, toke
Add xdp_info selftest that makes sure that bpf_get_link_xdp_id returns
valid prog_id for different input modes:
* w/ and w/o flags when no program is attached;
* w/ and w/o flags when one program is attached.
Signed-off-by: Andrey Ignatov <rdna@fb.com>
---
.../selftests/bpf/prog_tests/xdp_info.c | 68 +++++++++++++++++++
1 file changed, 68 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_info.c
diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_info.c b/tools/testing/selftests/bpf/prog_tests/xdp_info.c
new file mode 100644
index 000000000000..d2d7a283d72f
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_info.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/if_link.h>
+#include <test_progs.h>
+
+#define IFINDEX_LO 1
+
+void test_xdp_info(void)
+{
+ __u32 len = sizeof(struct bpf_prog_info), duration = 0, prog_id;
+ const char *file = "./xdp_dummy.o";
+ struct bpf_prog_info info = {};
+ struct bpf_object *obj;
+ int err, prog_fd;
+
+ /* Get prog_id for XDP_ATTACHED_NONE mode */
+
+ err = bpf_get_link_xdp_id(IFINDEX_LO, &prog_id, 0);
+ if (CHECK(err, "get_xdp_none", "errno=%d\n", errno))
+ return;
+ if (CHECK(prog_id, "prog_id_none", "unexpected prog_id=%u\n", prog_id))
+ return;
+
+ err = bpf_get_link_xdp_id(IFINDEX_LO, &prog_id, XDP_FLAGS_SKB_MODE);
+ if (CHECK(err, "get_xdp_none_skb", "errno=%d\n", errno))
+ return;
+ if (CHECK(prog_id, "prog_id_none_skb", "unexpected prog_id=%u\n",
+ prog_id))
+ return;
+
+ /* Setup prog */
+
+ err = bpf_prog_load(file, BPF_PROG_TYPE_XDP, &obj, &prog_fd);
+ if (CHECK_FAIL(err))
+ return;
+
+ err = bpf_obj_get_info_by_fd(prog_fd, &info, &len);
+ if (CHECK(err, "get_prog_info", "errno=%d\n", errno))
+ goto out_close;
+
+ err = bpf_set_link_xdp_fd(IFINDEX_LO, prog_fd, XDP_FLAGS_SKB_MODE);
+ if (CHECK(err, "set_xdp_skb", "errno=%d\n", errno))
+ goto out_close;
+
+ /* Get prog_id for single prog mode */
+
+ err = bpf_get_link_xdp_id(IFINDEX_LO, &prog_id, 0);
+ if (CHECK(err, "get_xdp", "errno=%d\n", errno))
+ goto out;
+ if (CHECK(prog_id != info.id, "prog_id", "prog_id not available\n"))
+ goto out;
+
+ err = bpf_get_link_xdp_id(IFINDEX_LO, &prog_id, XDP_FLAGS_SKB_MODE);
+ if (CHECK(err, "get_xdp_skb", "errno=%d\n", errno))
+ goto out;
+ if (CHECK(prog_id != info.id, "prog_id_skb", "prog_id not available\n"))
+ goto out;
+
+ err = bpf_get_link_xdp_id(IFINDEX_LO, &prog_id, XDP_FLAGS_DRV_MODE);
+ if (CHECK(err, "get_xdp_drv", "errno=%d\n", errno))
+ goto out;
+ if (CHECK(prog_id, "prog_id_drv", "unexpected prog_id=%u\n", prog_id))
+ goto out;
+
+out:
+ bpf_set_link_xdp_fd(IFINDEX_LO, -1, 0);
+out_close:
+ bpf_object__close(obj);
+}
--
2.24.1
^ permalink raw reply related [flat|nested] 5+ messages in thread