net: preserve IP control block during GSO segmentation

[mirror_ubuntu-bionic-kernel.git] / include / linux / skbuff.h

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 6b6bd42d6134a3bfccb36f0bad4447c8c35ab3ff..11f935c1a090419d6cda938aa925bfa79de3616b 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2805,6 +2805,23 @@ static inline void skb_postpull_rcsum(struct sk_buff *skb,
 
 unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len);
 
+static inline void skb_postpush_rcsum(struct sk_buff *skb,
+                                     const void *start, unsigned int len)
+{
+       /* For performing the reverse operation to skb_postpull_rcsum(),
+        * we can instead of ...
+        *
+        *   skb->csum = csum_add(skb->csum, csum_partial(start, len, 0));
+        *
+        * ... just use this equivalent version here to save a few
+        * instructions. Feeding csum of 0 in csum_partial() and later
+        * on adding skb->csum is equivalent to feed skb->csum in the
+        * first place.
+        */
+       if (skb->ip_summed == CHECKSUM_COMPLETE)
+               skb->csum = csum_partial(start, len, skb->csum);
+}
+
 /**
  *     pskb_trim_rcsum - trim received skb and update checksum
  *     @skb: buffer to trim
@@ -3534,7 +3551,8 @@ struct skb_gso_cb {
        int     encap_level;
        __u16   csum_start;
 };
-#define SKB_GSO_CB(skb) ((struct skb_gso_cb *)(skb)->cb)
+#define SKB_SGO_CB_OFFSET      32
+#define SKB_GSO_CB(skb) ((struct skb_gso_cb *)((skb)->cb + SKB_SGO_CB_OFFSET))
 
 static inline int skb_tnl_header_len(const struct sk_buff *inner_skb)
 {