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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Bob Pearson <rpearson@hpe.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 181/340] RDMA/rxe: Correct skb on loopback path
Date:   Mon,  1 Mar 2021 17:12:05 +0100
Message-Id: <20210301161057.220115420@linuxfoundation.org>
In-Reply-To: <20210301161048.294656001@linuxfoundation.org>
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From: Bob Pearson <rpearsonhpe@gmail.com>

[ 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@hpe.com
Signed-off-by: Bob Pearson <rpearson@hpe.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 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 312c2fc961c00..d411356828911 100644
--- a/drivers/infiniband/sw/rxe/rxe_net.c
+++ b/drivers/infiniband/sw/rxe/rxe_net.c
@@ -453,6 +453,11 @@ 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