[IPv4/IPv6]: UFO Scatter-gather approach

[net-next-2.6.git] / net / core / skbuff.c

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index ef9d46b91eb9200fa3eaf9fbc428808fcf1663c4..95501e40100e72f986ca5208cdabe9be01feeb68 100644 (file)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -176,6 +176,8 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask,
        skb_shinfo(skb)->tso_size = 0;
        skb_shinfo(skb)->tso_segs = 0;
        skb_shinfo(skb)->frag_list = NULL;
+       skb_shinfo(skb)->ufo_size = 0;
+       skb_shinfo(skb)->ip6_frag_id = 0;
 out:
        return skb;
 nodata:
@@ -1696,6 +1698,78 @@ unsigned int skb_find_text(struct sk_buff *skb, unsigned int from,
        return textsearch_find(config, state);
 }
 
+/**
+ * skb_append_datato_frags: - append the user data to a skb
+ * @sk: sock  structure
+ * @skb: skb structure to be appened with user data.
+ * @getfrag: call back function to be used for getting the user data
+ * @from: pointer to user message iov
+ * @length: length of the iov message
+ *
+ * Description: This procedure append the user data in the fragment part
+ * of the skb if any page alloc fails user this procedure returns  -ENOMEM
+ */
+int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
+                       int getfrag(void *from, char *to, int offset,
+                                       int len, int odd, struct sk_buff *skb),
+                       void *from, int length)
+{
+       int frg_cnt = 0;
+       skb_frag_t *frag = NULL;
+       struct page *page = NULL;
+       int copy, left;
+       int offset = 0;
+       int ret;
+
+       do {
+               /* Return error if we don't have space for new frag */
+               frg_cnt = skb_shinfo(skb)->nr_frags;
+               if (frg_cnt >= MAX_SKB_FRAGS)
+                       return -EFAULT;
+
+               /* allocate a new page for next frag */
+               page = alloc_pages(sk->sk_allocation, 0);
+
+               /* If alloc_page fails just return failure and caller will
+                * free previous allocated pages by doing kfree_skb()
+                */
+               if (page == NULL)
+                       return -ENOMEM;
+
+               /* initialize the next frag */
+               sk->sk_sndmsg_page = page;
+               sk->sk_sndmsg_off = 0;
+               skb_fill_page_desc(skb, frg_cnt, page, 0, 0);
+               skb->truesize += PAGE_SIZE;
+               atomic_add(PAGE_SIZE, &sk->sk_wmem_alloc);
+
+               /* get the new initialized frag */
+               frg_cnt = skb_shinfo(skb)->nr_frags;
+               frag = &skb_shinfo(skb)->frags[frg_cnt - 1];
+
+               /* copy the user data to page */
+               left = PAGE_SIZE - frag->page_offset;
+               copy = (length > left)? left : length;
+
+               ret = getfrag(from, (page_address(frag->page) +
+                           frag->page_offset + frag->size),
+                           offset, copy, 0, skb);
+               if (ret < 0)
+                       return -EFAULT;
+
+               /* copy was successful so update the size parameters */
+               sk->sk_sndmsg_off += copy;
+               frag->size += copy;
+               skb->len += copy;
+               skb->data_len += copy;
+               offset += copy;
+               length -= copy;
+
+       } while (length > 0);
+
+       return 0;
+}
+
 void __init skb_init(void)
 {
        skbuff_head_cache = kmem_cache_create("skbuff_head_cache",
@@ -1747,3 +1821,4 @@ EXPORT_SYMBOL(skb_prepare_seq_read);
 EXPORT_SYMBOL(skb_seq_read);
 EXPORT_SYMBOL(skb_abort_seq_read);
 EXPORT_SYMBOL(skb_find_text);
+EXPORT_SYMBOL(skb_append_datato_frags);