[PATCH 4.6 071/203] net_sched: fix mirrored packets checksum

Greg Kroah-Hartman
2016-07-25T22:14:09Z

From: WANG Cong <xiyou.wangcong@gmail.com>

[ Upstream commit 82a31b9231f02d9c1b7b290a46999d517b0d312a ]

Similar to commit 9b368814b336 ("net: fix bridge multicast packet checksum validation")
we need to fixup the checksum for CHECKSUM_COMPLETE when
pushing skb on RX path. Otherwise we get similar splats.

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Tom Herbert <tom@herbertland.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/linux/skbuff.h | 19 +++++++++++++++++++
net/core/skbuff.c | 18 ------------------
net/sched/act_mirred.c | 2 +-
3 files changed, 20 insertions(+), 19 deletions(-)

--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2861,6 +2861,25 @@ static inline void skb_postpush_rcsum(st
}

/**
+ * skb_push_rcsum - push skb and update receive checksum
+ * @skb: buffer to update
+ * @len: length of data pulled
+ *
+ * This function performs an skb_push on the packet and updates
+ * the CHECKSUM_COMPLETE checksum. It should be used on
+ * receive path processing instead of skb_push unless you know
+ * that the checksum difference is zero (e.g., a valid IP header)
+ * or you are setting ip_summed to CHECKSUM_NONE.
+ */
+static inline unsigned char *skb_push_rcsum(struct sk_buff *skb,
+ unsigned int len)
+{
+ skb_push(skb, len);
+ skb_postpush_rcsum(skb, skb->data, len);
+ return skb->data;
+}
+
+/**
* pskb_trim_rcsum - trim received skb and update checksum
* @skb: buffer to trim
* @len: new length
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3016,24 +3016,6 @@ int skb_append_pagefrags(struct sk_buff
EXPORT_SYMBOL_GPL(skb_append_pagefrags);

/**
- * skb_push_rcsum - push skb and update receive checksum
- * @skb: buffer to update
- * @len: length of data pulled
- *
- * This function performs an skb_push on the packet and updates
- * the CHECKSUM_COMPLETE checksum. It should be used on
- * receive path processing instead of skb_push unless you know
- * that the checksum difference is zero (e.g., a valid IP header)
- * or you are setting ip_summed to CHECKSUM_NONE.
- */
-static unsigned char *skb_push_rcsum(struct sk_buff *skb, unsigned len)
-{
- skb_push(skb, len);
- skb_postpush_rcsum(skb, skb->data, len);
- return skb->data;
-}
-
-/**
* skb_pull_rcsum - pull skb and update receive checksum
* @skb: buffer to update
* @len: length of data pulled
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -180,7 +180,7 @@ static int tcf_mirred(struct sk_buff *sk

if (!(at & AT_EGRESS)) {
if (m->tcfm_ok_push)
- skb_push(skb2, skb->mac_len);
+ skb_push_rcsum(skb2, skb->mac_len);
}

/* mirror is always swallowed */