[RFC PATCH 14/17] libbpf: Add support for querying dequeue programs

[Toke Høiland-Jørgensen <toke@xxxxxxxxxx>]

Add support to libbpf for reading the dequeue program ID from netlink when
querying for installed XDP programs. No additional support is needed to
install dequeue programs, as they are just using a new mode flag for the
regular XDP program installation mechanism.

Signed-off-by: Toke Høiland-Jørgensen <toke@xxxxxxxxxx>
---
 tools/lib/bpf/libbpf.h  | 1 +
 tools/lib/bpf/netlink.c | 8 ++++++++
 2 files changed, 9 insertions(+)

diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index e4d5353f757b..b15ff90279cb 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -906,6 +906,7 @@ struct bpf_xdp_query_opts {
 	__u32 drv_prog_id;	/* output */
 	__u32 hw_prog_id;	/* output */
 	__u32 skb_prog_id;	/* output */
+	__u32 dequeue_prog_id;	/* output */
 	__u8 attach_mode;	/* output */
 	size_t :0;
 };
diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c
index 6c013168032d..64a9aceb9c9c 100644
--- a/tools/lib/bpf/netlink.c
+++ b/tools/lib/bpf/netlink.c
@@ -32,6 +32,7 @@ struct xdp_link_info {
 	__u32 drv_prog_id;
 	__u32 hw_prog_id;
 	__u32 skb_prog_id;
+	__u32 dequeue_prog_id;
 	__u8 attach_mode;
 };
 
@@ -354,6 +355,10 @@ static int get_xdp_info(void *cookie, void *msg, struct nlattr **tb)
 		xdp_id->info.hw_prog_id = libbpf_nla_getattr_u32(
 			xdp_tb[IFLA_XDP_HW_PROG_ID]);
 
+	if (xdp_tb[IFLA_XDP_DEQUEUE_PROG_ID])
+		xdp_id->info.dequeue_prog_id = libbpf_nla_getattr_u32(
+			xdp_tb[IFLA_XDP_DEQUEUE_PROG_ID]);
+
 	return 0;
 }
 
@@ -391,6 +396,7 @@ int bpf_xdp_query(int ifindex, int xdp_flags, struct bpf_xdp_query_opts *opts)
 	OPTS_SET(opts, drv_prog_id, xdp_id.info.drv_prog_id);
 	OPTS_SET(opts, hw_prog_id, xdp_id.info.hw_prog_id);
 	OPTS_SET(opts, skb_prog_id, xdp_id.info.skb_prog_id);
+	OPTS_SET(opts, dequeue_prog_id, xdp_id.info.dequeue_prog_id);
 	OPTS_SET(opts, attach_mode, xdp_id.info.attach_mode);
 
 	return 0;
@@ -415,6 +421,8 @@ int bpf_xdp_query_id(int ifindex, int flags, __u32 *prog_id)
 		*prog_id = opts.hw_prog_id;
 	else if (flags & XDP_FLAGS_SKB_MODE)
 		*prog_id = opts.skb_prog_id;
+	else if (flags & XDP_FLAGS_DEQUEUE_MODE)
+		*prog_id = opts.dequeue_prog_id;
 	else
 		*prog_id = 0;
 
-- 
2.37.0