diff options
author | Herbert Xu <herbert@gondor.apana.org.au> | 2006-06-22 14:02:40 +0400 |
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committer | David S. Miller <davem@sunset.davemloft.net> | 2006-06-23 13:07:33 +0400 |
commit | f4c50d990dcf11a296679dc05de3873783236711 (patch) | |
tree | f4daf1c80fe591d45631e998b0b5d31d6fe76d85 /net/core/skbuff.c | |
parent | f6a78bfcb141f963187464bac838d46a81c3882a (diff) | |
download | linux-f4c50d990dcf11a296679dc05de3873783236711.tar.xz |
[NET]: Add software TSOv4
This patch adds the GSO implementation for IPv4 TCP.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/skbuff.c')
-rw-r--r-- | net/core/skbuff.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 368d98578c14..8e5044ba3ab6 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1842,6 +1842,132 @@ unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len) EXPORT_SYMBOL_GPL(skb_pull_rcsum); +/** + * skb_segment - Perform protocol segmentation on skb. + * @skb: buffer to segment + * @sg: whether scatter-gather can be used for generated segments + * + * This function performs segmentation on the given skb. It returns + * the segment at the given position. It returns NULL if there are + * no more segments to generate, or when an error is encountered. + */ +struct sk_buff *skb_segment(struct sk_buff *skb, int sg) +{ + struct sk_buff *segs = NULL; + struct sk_buff *tail = NULL; + unsigned int mss = skb_shinfo(skb)->gso_size; + unsigned int doffset = skb->data - skb->mac.raw; + unsigned int offset = doffset; + unsigned int headroom; + unsigned int len; + int nfrags = skb_shinfo(skb)->nr_frags; + int err = -ENOMEM; + int i = 0; + int pos; + + __skb_push(skb, doffset); + headroom = skb_headroom(skb); + pos = skb_headlen(skb); + + do { + struct sk_buff *nskb; + skb_frag_t *frag; + int hsize, nsize; + int k; + int size; + + len = skb->len - offset; + if (len > mss) + len = mss; + + hsize = skb_headlen(skb) - offset; + if (hsize < 0) + hsize = 0; + nsize = hsize + doffset; + if (nsize > len + doffset || !sg) + nsize = len + doffset; + + nskb = alloc_skb(nsize + headroom, GFP_ATOMIC); + if (unlikely(!nskb)) + goto err; + + if (segs) + tail->next = nskb; + else + segs = nskb; + tail = nskb; + + nskb->dev = skb->dev; + nskb->priority = skb->priority; + nskb->protocol = skb->protocol; + nskb->dst = dst_clone(skb->dst); + memcpy(nskb->cb, skb->cb, sizeof(skb->cb)); + nskb->pkt_type = skb->pkt_type; + nskb->mac_len = skb->mac_len; + + skb_reserve(nskb, headroom); + nskb->mac.raw = nskb->data; + nskb->nh.raw = nskb->data + skb->mac_len; + nskb->h.raw = nskb->nh.raw + (skb->h.raw - skb->nh.raw); + memcpy(skb_put(nskb, doffset), skb->data, doffset); + + if (!sg) { + nskb->csum = skb_copy_and_csum_bits(skb, offset, + skb_put(nskb, len), + len, 0); + continue; + } + + frag = skb_shinfo(nskb)->frags; + k = 0; + + nskb->ip_summed = CHECKSUM_HW; + nskb->csum = skb->csum; + memcpy(skb_put(nskb, hsize), skb->data + offset, hsize); + + while (pos < offset + len) { + BUG_ON(i >= nfrags); + + *frag = skb_shinfo(skb)->frags[i]; + get_page(frag->page); + size = frag->size; + + if (pos < offset) { + frag->page_offset += offset - pos; + frag->size -= offset - pos; + } + + k++; + + if (pos + size <= offset + len) { + i++; + pos += size; + } else { + frag->size -= pos + size - (offset + len); + break; + } + + frag++; + } + + skb_shinfo(nskb)->nr_frags = k; + nskb->data_len = len - hsize; + nskb->len += nskb->data_len; + nskb->truesize += nskb->data_len; + } while ((offset += len) < skb->len); + + return segs; + +err: + while ((skb = segs)) { + segs = skb->next; + kfree(skb); + } + return ERR_PTR(err); +} + +EXPORT_SYMBOL_GPL(skb_segment); + void __init skb_init(void) { skbuff_head_cache = kmem_cache_create("skbuff_head_cache", |