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| author | Daniel Borkmann <dborkman@redhat.com> | 2013-10-30 11:50:51 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-11-03 23:04:57 -0500 |
| commit | 2817a336d4d533fb8b68719723cd60ea7dd7c09e (patch) | |
| tree | 71aac3aa2a48588fd0b5372cca9499bd1cbe2a5f /net/core | |
| parent | efba721f636ee016859d86d15748650119402b10 (diff) | |
| download | linux-2817a336d4d533fb8b68719723cd60ea7dd7c09e.tar.gz linux-2817a336d4d533fb8b68719723cd60ea7dd7c09e.tar.bz2 linux-2817a336d4d533fb8b68719723cd60ea7dd7c09e.zip | |
net: skb_checksum: allow custom update/combine for walking skb
Currently, skb_checksum walks over 1) linearized, 2) frags[], and
3) frag_list data and calculats the one's complement, a 32 bit
result suitable for feeding into itself or csum_tcpudp_magic(),
but unsuitable for SCTP as we're calculating CRC32c there.
Hence, in order to not re-implement the very same function in
SCTP (and maybe other protocols) over and over again, use an
update() + combine() callback internally to allow for walking
over the skb with different algorithms.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/skbuff.c | 31 |
1 files changed, 21 insertions, 10 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 0ab32faa520f..31aab5376cb4 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1928,9 +1928,8 @@ fault: EXPORT_SYMBOL(skb_store_bits); /* Checksum skb data. */ - -__wsum skb_checksum(const struct sk_buff *skb, int offset, - int len, __wsum csum) +__wsum __skb_checksum(const struct sk_buff *skb, int offset, int len, + __wsum csum, const struct skb_checksum_ops *ops) { int start = skb_headlen(skb); int i, copy = start - offset; @@ -1941,7 +1940,7 @@ __wsum skb_checksum(const struct sk_buff *skb, int offset, if (copy > 0) { if (copy > len) copy = len; - csum = csum_partial(skb->data + offset, copy, csum); + csum = ops->update(skb->data + offset, copy, csum); if ((len -= copy) == 0) return csum; offset += copy; @@ -1962,10 +1961,10 @@ __wsum skb_checksum(const struct sk_buff *skb, int offset, if (copy > len) copy = len; vaddr = kmap_atomic(skb_frag_page(frag)); - csum2 = csum_partial(vaddr + frag->page_offset + - offset - start, copy, 0); + csum2 = ops->update(vaddr + frag->page_offset + + offset - start, copy, 0); kunmap_atomic(vaddr); - csum = csum_block_add(csum, csum2, pos); + csum = ops->combine(csum, csum2, pos, copy); if (!(len -= copy)) return csum; offset += copy; @@ -1984,9 +1983,9 @@ __wsum skb_checksum(const struct sk_buff *skb, int offset, __wsum csum2; if (copy > len) copy = len; - csum2 = skb_checksum(frag_iter, offset - start, - copy, 0); - csum = csum_block_add(csum, csum2, pos); + csum2 = __skb_checksum(frag_iter, offset - start, + copy, 0, ops); + csum = ops->combine(csum, csum2, pos, copy); if ((len -= copy) == 0) return csum; offset += copy; @@ -1998,6 +1997,18 @@ __wsum skb_checksum(const struct sk_buff *skb, int offset, return csum; } +EXPORT_SYMBOL(__skb_checksum); + +__wsum skb_checksum(const struct sk_buff *skb, int offset, + int len, __wsum csum) +{ + const struct skb_checksum_ops ops = { + .update = csum_partial, + .combine = csum_block_add_ext, + }; + + return __skb_checksum(skb, offset, len, csum, &ops); +} EXPORT_SYMBOL(skb_checksum); /* Both of above in one bottle. */ |