[PATCH 4.19 142/247] RDMA/rxe: Correct skb on loopback path

[Greg Kroah-Hartman]

From: Bob Pearson <rpearsonhpe@xxxxxxxxx>

[ Upstream commit 5120bf0a5fc15dec210a0fe0f39e4a256bb6e349 ]

rxe_net.c sends packets at the IP layer with skb->data pointing at the IP
header but receives packets from a UDP tunnel with skb->data pointing at
the UDP header.  On the loopback path this was not correctly accounted
for.  This patch corrects for this by using sbk_pull() to strip the IP
header from the skb on received packets.

Fixes: 8700e3e7c485 ("Soft RoCE driver")
Link: https://lore.kernel.org/r/20210128182301.16859-1-rpearson@xxxxxxx
Signed-off-by: Bob Pearson <rpearson@xxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/infiniband/sw/rxe/rxe_net.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/infiniband/sw/rxe/rxe_net.c b/drivers/infiniband/sw/rxe/rxe_net.c
index 7903bd5c639ea..04bfc36cc8d76 100644
--- a/drivers/infiniband/sw/rxe/rxe_net.c
+++ b/drivers/infiniband/sw/rxe/rxe_net.c
@@ -500,6 +500,11 @@ int rxe_send(struct rxe_pkt_info *pkt, struct sk_buff *skb)
 
 void rxe_loopback(struct sk_buff *skb)
 {
+	if (skb->protocol == htons(ETH_P_IP))
+		skb_pull(skb, sizeof(struct iphdr));
+	else
+		skb_pull(skb, sizeof(struct ipv6hdr));
+
 	rxe_rcv(skb);
 }
 
-- 
2.27.0