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Commit 9617813d authored by Davide Caratti's avatar Davide Caratti Committed by David S. Miller
Browse files

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: default avatarDavide Caratti <dcaratti@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6f5b24ee

include/linux/skbuff.h

+2 −0
Original line number Diff line number Diff line
@@ -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,

net/core/skbuff.c

+26 −0
Original line number Diff line number Diff line
@@ -2243,6 +2243,32 @@ __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, 
}

EXPORT_SYMBOL(skb_copy_and_csum_bits);



static __wsum warn_crc32c_csum_update(const void *buff, int len, __wsum sum)

{

	net_warn_ratelimited(

		"%s: attempt to compute crc32c without libcrc32c.ko\n",

		__func__);

	return 0;

}



static __wsum warn_crc32c_csum_combine(__wsum csum, __wsum csum2,

				       int offset, int len)

{

	net_warn_ratelimited(

		"%s: attempt to compute crc32c without libcrc32c.ko\n",

		__func__);

	return 0;

}



static const struct skb_checksum_ops default_crc32c_ops = {

	.update  = warn_crc32c_csum_update,

	.combine = warn_crc32c_csum_combine,

};



const struct skb_checksum_ops *crc32c_csum_stub __read_mostly =

	&default_crc32c_ops;

EXPORT_SYMBOL(crc32c_csum_stub);



 /**

 *	skb_zerocopy_headlen - Calculate headroom needed for skb_zerocopy()

 *	@from: source buffer

net/sctp/offload.c

+6 −0
Original line number Diff line number Diff line
@@ -98,6 +98,11 @@ static const struct net_offload sctp6_offload = { 
	},

};



static const struct skb_checksum_ops crc32c_csum_ops = {

	.update  = sctp_csum_update,

	.combine = sctp_csum_combine,

};



int __init sctp_offload_init(void)

{

	int ret;
@@ -110,6 +115,7 @@ int __init sctp_offload_init(void) 
	if (ret)

		goto ipv4;



	crc32c_csum_stub = &crc32c_csum_ops;

	return ret;



ipv4: