From 2817a336d4d533fb8b68719723cd60ea7dd7c09e Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Wed, 30 Oct 2013 11:50:51 +0100 Subject: 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 Signed-off-by: David S. Miller --- include/linux/skbuff.h | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 2c154976394b..44727b5d4981 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -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) { -- cgit v1.2.3