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authorHerbert Xu <herbert@gondor.apana.org.au>2008-07-25 05:55:33 -0400
committerDavid S. Miller <davem@davemloft.net>2008-07-25 05:55:33 -0400
commit7d7e5a60c62e88cb8782760bb6c4d3bd1577a6c6 (patch)
treec6bedd62097698466d7dc0b5166e4ed29e1b6ee5 /net/xfrm/xfrm_ipcomp.c
parent6fccab671f2f0a24b799f29a4ec878f62d34656c (diff)
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 @@
17 17
18#include <linux/crypto.h> 18#include <linux/crypto.h>
19#include <linux/err.h> 19#include <linux/err.h>
20#include <linux/gfp.h>
20#include <linux/list.h> 21#include <linux/list.h>
21#include <linux/module.h> 22#include <linux/module.h>
22#include <linux/mutex.h> 23#include <linux/mutex.h>
@@ -49,6 +50,7 @@ static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb)
49 u8 *scratch = *per_cpu_ptr(ipcomp_scratches, cpu); 50 u8 *scratch = *per_cpu_ptr(ipcomp_scratches, cpu);
50 struct crypto_comp *tfm = *per_cpu_ptr(ipcd->tfms, cpu); 51 struct crypto_comp *tfm = *per_cpu_ptr(ipcd->tfms, cpu);
51 int err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen); 52 int err = crypto_comp_decompress(tfm, start, plen, scratch, &dlen);
53 int len;
52 54
53 if (err) 55 if (err)
54 goto out; 56 goto out;
@@ -58,13 +60,47 @@ static int ipcomp_decompress(struct xfrm_state *x, struct sk_buff *skb)
58 goto out; 60 goto out;
59 } 61 }
60 62
61 err = pskb_expand_head(skb, 0, dlen - plen, GFP_ATOMIC); 63 len = dlen - plen;
62 if (err) 64 if (len > skb_tailroom(skb))
63 goto out; 65 len = skb_tailroom(skb);
66
67 skb->truesize += len;
68 __skb_put(skb, len);
69
70 len += plen;
71 skb_copy_to_linear_data(skb, scratch, len);
72
73 while ((scratch += len, dlen -= len) > 0) {
74 skb_frag_t *frag;
75
76 err = -EMSGSIZE;
77 if (WARN_ON(skb_shinfo(skb)->nr_frags >= MAX_SKB_FRAGS))
78 goto out;
79
80 frag = skb_shinfo(skb)->frags + skb_shinfo(skb)->nr_frags;
81 frag->page = alloc_page(GFP_ATOMIC);
82
83 err = -ENOMEM;
84 if (!frag->page)
85 goto out;
86
87 len = PAGE_SIZE;
88 if (dlen < len)
89 len = dlen;
90
91 memcpy(page_address(frag->page), scratch, len);
92
93 frag->page_offset = 0;
94 frag->size = len;
95 skb->truesize += len;
96 skb->data_len += len;
97 skb->len += len;
98
99 skb_shinfo(skb)->nr_frags++;
100 }
101
102 err = 0;
64 103
65 skb->truesize += dlen - plen;
66 __skb_put(skb, dlen - plen);
67 skb_copy_to_linear_data(skb, scratch, dlen);
68out: 104out:
69 put_cpu(); 105 put_cpu();
70 return err; 106 return err;