diff options
author | Herbert Xu <herbert@gondor.apana.org.au> | 2008-12-16 07:26:06 (GMT) |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2008-12-16 07:26:06 (GMT) |
commit | 89319d3801d1d3ac29c7df1f067038986f267d29 (patch) | |
tree | a717482d5cdfe9d50bed14a2114ece905b5e88d7 /net | |
parent | eb14f019597cd86c21a6c601d7e900f40030c2e7 (diff) | |
download | linux-89319d3801d1d3ac29c7df1f067038986f267d29.tar.xz |
net: Add frag_list support to skb_segment
This patch adds limited support for handling frag_list packets in
skb_segment. The intention is to support GRO (Generic Receive Offload)
packets which will be constructed by chaining normal packets using
frag_list.
As such we require all frag_list members terminate on exact MSS
boundaries. This is checked using BUG_ON.
As there should only be one producer in the kernel of such packets,
namely GRO, this requirement should not be difficult to maintain.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r-- | net/core/skbuff.c | 73 |
1 files changed, 59 insertions, 14 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index b1f6287..18e224a 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2428,6 +2428,7 @@ struct sk_buff *skb_segment(struct sk_buff *skb, int features) { struct sk_buff *segs = NULL; struct sk_buff *tail = NULL; + struct sk_buff *fskb = skb_shinfo(skb)->frag_list; unsigned int mss = skb_shinfo(skb)->gso_size; unsigned int doffset = skb->data - skb_mac_header(skb); unsigned int offset = doffset; @@ -2447,7 +2448,6 @@ struct sk_buff *skb_segment(struct sk_buff *skb, int features) struct sk_buff *nskb; skb_frag_t *frag; int hsize; - int k; int size; len = skb->len - offset; @@ -2460,9 +2460,36 @@ struct sk_buff *skb_segment(struct sk_buff *skb, int features) if (hsize > len || !sg) hsize = len; - nskb = alloc_skb(hsize + doffset + headroom, GFP_ATOMIC); - if (unlikely(!nskb)) - goto err; + if (!hsize && i >= nfrags) { + BUG_ON(fskb->len != len); + + pos += len; + nskb = skb_clone(fskb, GFP_ATOMIC); + fskb = fskb->next; + + if (unlikely(!nskb)) + goto err; + + hsize = skb_end_pointer(nskb) - nskb->head; + if (skb_cow_head(nskb, doffset + headroom)) { + kfree_skb(nskb); + goto err; + } + + nskb->truesize += skb_end_pointer(nskb) - nskb->head - + hsize; + skb_release_head_state(nskb); + __skb_push(nskb, doffset); + } else { + nskb = alloc_skb(hsize + doffset + headroom, + GFP_ATOMIC); + + if (unlikely(!nskb)) + goto err; + + skb_reserve(nskb, headroom); + __skb_put(nskb, doffset); + } if (segs) tail->next = nskb; @@ -2473,13 +2500,15 @@ struct sk_buff *skb_segment(struct sk_buff *skb, int features) __copy_skb_header(nskb, skb); nskb->mac_len = skb->mac_len; - skb_reserve(nskb, headroom); skb_reset_mac_header(nskb); skb_set_network_header(nskb, skb->mac_len); nskb->transport_header = (nskb->network_header + skb_network_header_len(skb)); - skb_copy_from_linear_data(skb, skb_put(nskb, doffset), - doffset); + skb_copy_from_linear_data(skb, nskb->data, doffset); + + if (pos >= offset + len) + continue; + if (!sg) { nskb->ip_summed = CHECKSUM_NONE; nskb->csum = skb_copy_and_csum_bits(skb, offset, @@ -2489,14 +2518,11 @@ struct sk_buff *skb_segment(struct sk_buff *skb, int features) } frag = skb_shinfo(nskb)->frags; - k = 0; skb_copy_from_linear_data_offset(skb, offset, skb_put(nskb, hsize), hsize); - while (pos < offset + len) { - BUG_ON(i >= nfrags); - + while (pos < offset + len && i < nfrags) { *frag = skb_shinfo(skb)->frags[i]; get_page(frag->page); size = frag->size; @@ -2506,20 +2532,39 @@ struct sk_buff *skb_segment(struct sk_buff *skb, int features) frag->size -= offset - pos; } - k++; + skb_shinfo(nskb)->nr_frags++; if (pos + size <= offset + len) { i++; pos += size; } else { frag->size -= pos + size - (offset + len); - break; + goto skip_fraglist; } frag++; } - skb_shinfo(nskb)->nr_frags = k; + if (pos < offset + len) { + struct sk_buff *fskb2 = fskb; + + BUG_ON(pos + fskb->len != offset + len); + + pos += fskb->len; + fskb = fskb->next; + + if (fskb2->next) { + fskb2 = skb_clone(fskb2, GFP_ATOMIC); + if (!fskb2) + goto err; + } else + skb_get(fskb2); + + BUG_ON(skb_shinfo(nskb)->frag_list); + skb_shinfo(nskb)->frag_list = fskb2; + } + +skip_fraglist: nskb->data_len = len - hsize; nskb->len += nskb->data_len; nskb->truesize += nskb->data_len; |