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authorHerbert Xu <herbert@gondor.apana.org.au>2008-07-25 02:55:33 -0700
committerDavid S. Miller <davem@davemloft.net>2008-07-25 02:55:33 -0700
commit7d7e5a60c62e88cb8782760bb6c4d3bd1577a6c6 (patch)
treec6bedd62097698466d7dc0b5166e4ed29e1b6ee5 /net/xfrm/xfrm_ipcomp.c
parent6fccab671f2f0a24b799f29a4ec878f62d34656c (diff)
downloadlinux-2.6.38-lt-ux500-7d7e5a60c62e88cb8782760bb6c4d3bd1577a6c6.tar.gz
ipsec: ipcomp - Decompress into frags if necessary
When decompressing extremely large packets allocating them through kmalloc is prone to failure. Therefore it's better to use page frags instead. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/xfrm/xfrm_ipcomp.c')
-rw-r--r--net/xfrm/xfrm_ipcomp.c48
1 files changed, 42 insertions, 6 deletions
diff --git a/net/xfrm/xfrm_ipcomp.c b/net/xfrm/xfrm_ipcomp.c
index b51e804fbba..800f669083f 100644
--- a/net/xfrm/xfrm_ipcomp.c
+++ b/net/xfrm/xfrm_ipcomp.c
@@ -17,6 +17,7 @@
#include <linux/crypto.h>
#include <linux/err.h>
+#include <linux/gfp.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
@@ -49,6 +50,7 @@ static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb)
u8 *scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
struct crypto_comp *tfm = *per_cpu_ptr(ipcd->tfms, cpu);
int err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
+ int len;
if (err)
goto out;
@@ -58,13 +60,47 @@ static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb)
goto out;
}
- err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC);
- if (err)
- goto out;
+ len = dlen - plen;
+ if (len > skb_tailroom(skb))
+ len = skb_tailroom(skb);
+
+ skb->truesize += len;
+ __skb_put(skb, len);
+
+ len += plen;
+ skb_copy_to_linear_data(skb, scratch, len);
+
+ while ((scratch += len, dlen -= len) > 0) {
+ skb_frag_t *frag;
+
+ err = -EMSGSIZE;
+ if (WARN_ON(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS))
+ goto out;
+
+ frag = skb_shinfo(skb)->frags + skb_shinfo(skb)->nr_frags;
+ frag->page = alloc_page(GFP_ATOMIC);
+
+ err = -ENOMEM;
+ if (!frag->page)
+ goto out;
+
+ len = PAGE_SIZE;
+ if (dlen < len)
+ len = dlen;
+
+ memcpy(page_address(frag->page), scratch, len);
+
+ frag->page_offset = 0;
+ frag->size = len;
+ skb->truesize += len;
+ skb->data_len += len;
+ skb->len += len;
+
+ skb_shinfo(skb)->nr_frags++;
+ }
+
+ err = 0;
- skb->truesize += dlen - plen;
- __skb_put(skb, dlen - plen);
- skb_copy_to_linear_data(skb, scratch, dlen);
out:
put_cpu();
return err;