netdev - [PATCH v20 bpf-next 23/23] xdp: disable XDP

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Date:   Fri, 10 Dec 2021 20:14:30 +0100
From:   Lorenzo Bianconi <lorenzo@...nel.org>
To:     bpf@...r.kernel.org, netdev@...r.kernel.org
Cc:     lorenzo.bianconi@...hat.com, davem@...emloft.net, kuba@...nel.org,
        ast@...nel.org, daniel@...earbox.net, shayagr@...zon.com,
        john.fastabend@...il.com, dsahern@...nel.org, brouer@...hat.com,
        echaudro@...hat.com, jasowang@...hat.com,
        alexander.duyck@...il.com, saeed@...nel.org,
        maciej.fijalkowski@...el.com, magnus.karlsson@...el.com,
        tirthendu.sarkar@...el.com, toke@...hat.com
Subject: [PATCH v20 bpf-next 23/23] xdp: disable XDP_REDIRECT for xdp multi-buff

XDP_REDIRECT is not fully supported yet for xdp multi-buff since not
all XDP capable drivers can map non-linear xdp_frame in ndo_xdp_xmit
so disable it for the moment.

Signed-off-by: Lorenzo Bianconi <lorenzo@...nel.org>
---
 net/core/filter.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/net/core/filter.c b/net/core/filter.c
index 14860931733d..def6e9f451a7 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4186,6 +4186,13 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp,
 	struct bpf_map *map;
 	int err;
 
+	/* XDP_REDIRECT is not fully supported yet for xdp multi-buff since
+	 * not all XDP capable drivers can map non-linear xdp_frame in
+	 * ndo_xdp_xmit.
+	 */
+	if (unlikely(xdp_buff_is_mb(xdp) && map_type != BPF_MAP_TYPE_CPUMAP))
+		return -EOPNOTSUPP;
+
 	ri->map_id = 0; /* Valid map id idr range: [1,INT_MAX[ */
 	ri->map_type = BPF_MAP_TYPE_UNSPEC;
 
-- 
2.33.1