diff mbox

[net-next,v2,1/7] skbuff: add stub to help computing crc32c on SCTP packets

Message ID 970ffbc429b9297c3038f12f4b9cad1afbdbc375.1494946940.git.dcaratti@redhat.com
State Changes Requested, archived
Delegated to: David Miller
Headers show

Commit Message

Davide Caratti May 16, 2017, 4:27 p.m. UTC 
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.

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Davide Caratti <dcaratti@redhat.com>
---
 include/linux/skbuff.h |  2 ++
 net/core/skbuff.c      | 24 ++++++++++++++++++++++++
 net/sctp/offload.c     |  7 +++++++
 3 files changed, 33 insertions(+)

Comments

David Miller May 17, 2017, 4:08 p.m. UTC | #1 
From: Davide Caratti <dcaratti@redhat.com>
Date: Tue, 16 May 2017 18:27:45 +0200

> @@ -2243,6 +2243,30 @@ __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;
> +}
> +
> +const struct skb_checksum_ops *crc32c_csum_stub __read_mostly =
> +	&(struct skb_checksum_ops) {
> +	.update  = warn_crc32c_csum_update,
> +	.combine = warn_crc32c_csum_combine,
> +};
> +EXPORT_SYMBOL(crc32c_csum_stub);

Please, if you are going to do this, declare things in a more
traditional and canonical way:

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;

> +static const struct skb_checksum_ops *crc32c_csum_ops __read_mostly =
> +	&(struct skb_checksum_ops) {
> +	.update  = sctp_csum_update,
> +	.combine = sctp_csum_combine,
> +};

Likewise.
diff mbox

Patch

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index a098d95..884a197 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3129,6 +3129,8 @@  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,
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 346d3e8..12e3cb7 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -2243,6 +2243,30 @@  __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;
+}
+
+const struct skb_checksum_ops *crc32c_csum_stub __read_mostly =
+	&(struct skb_checksum_ops) {
+	.update  = warn_crc32c_csum_update,
+	.combine = warn_crc32c_csum_combine,
+};
+EXPORT_SYMBOL(crc32c_csum_stub);
+
  /**
  *	skb_zerocopy_headlen - Calculate headroom needed for skb_zerocopy()
  *	@from: source buffer
diff --git a/net/sctp/offload.c b/net/sctp/offload.c
index 4f5a2b5..378f462 100644
--- a/net/sctp/offload.c
+++ b/net/sctp/offload.c
@@ -98,6 +98,12 @@  static const struct net_offload sctp6_offload = {
 	},
 };
 
+static const struct skb_checksum_ops *crc32c_csum_ops __read_mostly =
+	&(struct skb_checksum_ops) {
+	.update  = sctp_csum_update,
+	.combine = sctp_csum_combine,
+};
+
 int __init sctp_offload_init(void)
 {
 	int ret;
@@ -110,6 +116,7 @@  int __init sctp_offload_init(void)
 	if (ret)
 		goto ipv4;
 
+	crc32c_csum_stub = crc32c_csum_ops;
 	return ret;
 
 ipv4: