skbuff: add stub to help computing crc32c on SCTP packets

sctp_compute_checksum requires crc32c symbol (provided by libcrc32c), so
it can't be used in net core. Like it has been done previously with other
symbols (e.g. ipv6_dst_lookup), introduce a stub struct skb_checksum_ops
to allow computation of crc32c checksum in net core after sctp.ko (and thus
libcrc32c) has been loaded.

Signed-off-by: Davide Caratti <dcaratti@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 7c0cb2ce8b01..b1f46a0d18e2 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3076,6 +3076,8 @@ struct skb_checksum_ops {
         __wsum (*combine)(__wsum csum, __wsum csum2, int offset, int len);
 };
 
+extern const struct skb_checksum_ops *crc32c_csum_stub __read_mostly;
+
 __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,