+static void inline skb_split_inside_header(struct sk_buff *skb,
+ struct sk_buff* skb1,
+ const u32 len, const int pos)
+{
+ int i;
+
+ memcpy(skb_put(skb1, pos - len), skb->data + len, pos - len);
+
+ /* And move data appendix as is. */
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++)
+ skb_shinfo(skb1)->frags[i] = skb_shinfo(skb)->frags[i];
+
+ skb_shinfo(skb1)->nr_frags = skb_shinfo(skb)->nr_frags;
+ skb_shinfo(skb)->nr_frags = 0;
+ skb1->data_len = skb->data_len;
+ skb1->len += skb1->data_len;
+ skb->data_len = 0;
+ skb->len = len;
+ skb->tail = skb->data + len;
+}
+
+static void inline skb_split_no_header(struct sk_buff *skb,
+ struct sk_buff* skb1,
+ const u32 len, int pos)
+{
+ int i, k = 0;
+ const int nfrags = skb_shinfo(skb)->nr_frags;
+
+ skb_shinfo(skb)->nr_frags = 0;
+ skb1->len = skb1->data_len = skb->len - len;
+ skb->len = len;
+ skb->data_len = len - pos;
+
+ for (i = 0; i < nfrags; i++) {
+ int size = skb_shinfo(skb)->frags[i].size;
+
+ if (pos + size > len) {
+ skb_shinfo(skb1)->frags[k] = skb_shinfo(skb)->frags[i];
+
+ if (pos < len) {
+ /* Split frag.
+ * We have to variants in this case:
+ * 1. Move all the frag to the second
+ * part, if it is possible. F.e.
+ * this approach is mandatory for TUX,
+ * where splitting is expensive.
+ * 2. Split is accurately. We make this.
+ */
+ get_page(skb_shinfo(skb)->frags[i].page);
+ skb_shinfo(skb1)->frags[0].page_offset += len - pos;
+ skb_shinfo(skb1)->frags[0].size -= len - pos;
+ skb_shinfo(skb)->frags[i].size = len - pos;
+ skb_shinfo(skb)->nr_frags++;
+ }
+ k++;
+ } else
+ skb_shinfo(skb)->nr_frags++;
+ pos += size;
+ }
+ skb_shinfo(skb1)->nr_frags = k;
+}
+
+/**
+ * skb_split - Split fragmented skb to two parts at length len.
+ */
+void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len)
+{
+ int pos = skb_headlen(skb);
+
+ if (len < pos) /* Split line is inside header. */
+ skb_split_inside_header(skb, skb1, len, pos);
+ else /* Second chunk has no header, nothing to copy. */
+ skb_split_no_header(skb, skb1, len, pos);
+}
+