From 71d93b39e52e92aea35f1058d957cf12250d0b75 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Mon, 15 Dec 2008 23:42:33 -0800 Subject: [PATCH] net: Add skb_gro_receive This patch adds the helper skb_gro_receive to merge packets for GRO. The current method is to allocate a new header skb and then chain the original packets to its frag_list. This is done to make it easier to integrate into the existing GSO framework. In future as GSO is moved into the drivers, we can undo this and simply chain the original packets together. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- include/linux/skbuff.h | 2 ++ net/core/skbuff.c | 59 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 61 insertions(+) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index acf17af45af..cf2cb50f77d 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1687,6 +1687,8 @@ extern int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen); extern struct sk_buff *skb_segment(struct sk_buff *skb, int features); +extern int skb_gro_receive(struct sk_buff **head, + struct sk_buff *skb); static inline void *skb_header_pointer(const struct sk_buff *skb, int offset, int len, void *buffer) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 18e224af05a..b8d0abb2643 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2582,6 +2582,65 @@ err: EXPORT_SYMBOL_GPL(skb_segment); +int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb) +{ + struct sk_buff *p = *head; + struct sk_buff *nskb; + unsigned int headroom; + unsigned int hlen = p->data - skb_mac_header(p); + + if (hlen + p->len + skb->len >= 65536) + return -E2BIG; + + if (skb_shinfo(p)->frag_list) + goto merge; + + headroom = skb_headroom(p); + nskb = netdev_alloc_skb(p->dev, headroom); + if (unlikely(!nskb)) + return -ENOMEM; + + __copy_skb_header(nskb, p); + nskb->mac_len = p->mac_len; + + skb_reserve(nskb, headroom); + + skb_set_mac_header(nskb, -hlen); + skb_set_network_header(nskb, skb_network_offset(p)); + skb_set_transport_header(nskb, skb_transport_offset(p)); + + memcpy(skb_mac_header(nskb), skb_mac_header(p), hlen); + + *NAPI_GRO_CB(nskb) = *NAPI_GRO_CB(p); + skb_shinfo(nskb)->frag_list = p; + skb_header_release(p); + nskb->prev = p; + + nskb->data_len += p->len; + nskb->truesize += p->len; + nskb->len += p->len; + + *head = nskb; + nskb->next = p->next; + p->next = NULL; + + p = nskb; + +merge: + NAPI_GRO_CB(p)->count++; + p->prev->next = skb; + p->prev = skb; + skb_header_release(skb); + + p->data_len += skb->len; + p->truesize += skb->len; + p->len += skb->len; + + NAPI_GRO_CB(skb)->same_flow = 1; + return 0; +} +EXPORT_SYMBOL_GPL(skb_gro_receive); + void __init skb_init(void) { skbuff_head_cache = kmem_cache_create("skbuff_head_cache", -- 2.20.1