xdp: factor out common program/flags handling from drivers

Basic operations drivers perform during xdp setup and query can
be moved to helpers in the core.  Encapsulate program and flags
into a structure and add helpers.  Note that the structure is
intended as the "main" program information source in the driver.
Most drivers will additionally place the program pointer in their
fast path or ring structures.

The helpers don't have a huge impact now, but they will
decrease the code duplication when programs can be installed
in HW and driver at the same time.  Encapsulating the basic
operations in helpers will hopefully also reduce the number
of changes to drivers which adopt them.

Helpers could really be static inline, but they depend on
definition of struct netdev_bpf which means they'd have
to be placed in netdevice.h, an already 4500 line header.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

1 files changed, 34 insertions, 0 deletions

diff --git a/net/core/xdp.c b/net/core/xdp.c
index 31c58719b5a9..57285383ed00 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -3,8 +3,11 @@
  * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
  * Released under terms in GPL version 2.  See COPYING.
  */
+#include <linux/bpf.h>
+#include <linux/filter.h>
 #include <linux/types.h>
 #include <linux/mm.h>
+#include <linux/netdevice.h>
 #include <linux/slab.h>
 #include <linux/idr.h>
 #include <linux/rhashtable.h>
@@ -370,3 +373,34 @@ void xdp_return_buff(struct xdp_buff *xdp)
 	__xdp_return(xdp->data, &xdp->rxq->mem, true, xdp->handle);
 }
 EXPORT_SYMBOL_GPL(xdp_return_buff);
+
+int xdp_attachment_query(struct xdp_attachment_info *info,
+			 struct netdev_bpf *bpf)
+{
+	bpf->prog_id = info->prog ? info->prog->aux->id : 0;
+	bpf->prog_flags = info->prog ? info->flags : 0;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(xdp_attachment_query);
+
+bool xdp_attachment_flags_ok(struct xdp_attachment_info *info,
+			     struct netdev_bpf *bpf)
+{
+	if (info->prog && (bpf->flags ^ info->flags) & XDP_FLAGS_MODES) {
+		NL_SET_ERR_MSG(bpf->extack,
+			       "program loaded with different flags");
+		return false;
+	}
+	return true;
+}
+EXPORT_SYMBOL_GPL(xdp_attachment_flags_ok);
+
+void xdp_attachment_setup(struct xdp_attachment_info *info,
+			  struct netdev_bpf *bpf)
+{
+	if (info->prog)
+		bpf_prog_put(info->prog);
+	info->prog = bpf->prog;
+	info->flags = bpf->flags;
+}
+EXPORT_SYMBOL_GPL(xdp_attachment_setup);