@@ -2360,8 +2360,6 @@ int skb_copy_datagram_const_iovec(const struct sk_buff *from, int offset,
void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb);
int skb_kill_datagram(struct sock *sk, struct sk_buff *skb, unsigned int flags);
-__wsum skb_checksum(const struct sk_buff *skb, int offset, int len,
- __wsum csum);
int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);
int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len);
__wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to,
@@ -2373,9 +2371,18 @@ void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
void skb_split(struct sk_buff *skb, struct sk_buff *skb1, const u32 len);
int skb_shift(struct sk_buff *tgt, struct sk_buff *skb, int shiftlen);
void skb_scrub_packet(struct sk_buff *skb, bool xnet);
-
struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features);
+struct skb_checksum_ops {
+ __wsum (*update)(const void *mem, int len, __wsum wsum);
+ __wsum (*combine)(__wsum csum, __wsum csum2, int offset, int len);
+};
+
+__wsum __skb_checksum(const struct sk_buff *skb, int offset, int len,
+ __wsum csum, const struct skb_checksum_ops *ops);
+__wsum skb_checksum(const struct sk_buff *skb, int offset, int len,
+ __wsum csum);
+
static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
int len, void *buffer)
{
@@ -79,6 +79,12 @@ csum_block_add(__wsum csum, __wsum csum2, int offset)
}
static inline __wsum
+csum_block_add_ext(__wsum csum, __wsum csum2, int offset, int len)
+{
+ return csum_block_add(csum, csum2, offset);
+}
+
+static inline __wsum
csum_block_sub(__wsum csum, __wsum csum2, int offset)
{
u32 sum = (__force u32)csum2;
@@ -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. */
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> --- include/linux/skbuff.h | 13 ++++++++++--- include/net/checksum.h | 6 ++++++ net/core/skbuff.c | 31 +++++++++++++++++++++---------- 3 files changed, 37 insertions(+), 13 deletions(-)