Commit b72b5bf6 authored by Davide Caratti's avatar Davide Caratti Committed by David S. Miller
Browse files

net: introduce skb_crc32c_csum_help 



skb_crc32c_csum_help is like skb_checksum_help, but it is designed for
checksumming SCTP packets using crc32c (see RFC3309), provided that
libcrc32c.ko has been loaded before. In case libcrc32c is not loaded,
invoking skb_crc32c_csum_help on a skb results in one the following
printouts:

warn_crc32c_csum_update: attempt to compute crc32c without libcrc32c.ko
warn_crc32c_csum_combine: attempt to compute crc32c without libcrc32c.ko

Signed-off-by: default avatarDavide Caratti <dcaratti@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9617813d

include/linux/netdevice.h

+1 −0
Original line number Diff line number Diff line
@@ -3931,6 +3931,7 @@ void netdev_rss_key_fill(void *buffer, size_t len); 


int dev_get_nest_level(struct net_device *dev);

int skb_checksum_help(struct sk_buff *skb);

int skb_crc32c_csum_help(struct sk_buff *skb);

struct sk_buff *__skb_gso_segment(struct sk_buff *skb,

				  netdev_features_t features, bool tx_path);

struct sk_buff *skb_mac_gso_segment(struct sk_buff *skb,

include/linux/skbuff.h

+2 −1
Original line number Diff line number Diff line
@@ -193,7 +193,8 @@ 
 *     accordingly. Note the there is no indication in the skbuff that the

 *     CHECKSUM_PARTIAL refers to an SCTP checksum, a driver that supports

 *     both IP checksum offload and SCTP CRC offload must verify which offload

 *     is configured for a packet presumably by inspecting packet headers.

 *     is configured for a packet presumably by inspecting packet headers; in

 *     case, skb_crc32c_csum_help is provided to compute CRC on SCTP packets.

 *

 *   NETIF_F_FCOE_CRC - This feature indicates that a device is capable of

 *     offloading the FCOE CRC in a packet. To perform this offload the stack

net/core/dev.c

+41 −0
Original line number Diff line number Diff line
@@ -143,6 +143,7 @@ 
#include <linux/hrtimer.h>

#include <linux/netfilter_ingress.h>

#include <linux/crash_dump.h>

#include <linux/sctp.h>



#include "net-sysfs.h"
@@ -2612,6 +2613,46 @@ out: 
}

EXPORT_SYMBOL(skb_checksum_help);



int skb_crc32c_csum_help(struct sk_buff *skb)

{

	__le32 crc32c_csum;

	int ret = 0, offset, start;



	if (skb->ip_summed != CHECKSUM_PARTIAL)

		goto out;



	if (unlikely(skb_is_gso(skb)))

		goto out;



	/* Before computing a checksum, we should make sure no frag could

	 * be modified by an external entity : checksum could be wrong.

	 */

	if (unlikely(skb_has_shared_frag(skb))) {

		ret = __skb_linearize(skb);

		if (ret)

			goto out;

	}

	start = skb_checksum_start_offset(skb);

	offset = start + offsetof(struct sctphdr, checksum);

	if (WARN_ON_ONCE(offset >= skb_headlen(skb))) {

		ret = -EINVAL;

		goto out;

	}

	if (skb_cloned(skb) &&

	    !skb_clone_writable(skb, offset + sizeof(__le32))) {

		ret = pskb_expand_head(skb, 0, 0, GFP_ATOMIC);

		if (ret)

			goto out;

	}

	crc32c_csum = cpu_to_le32(~__skb_checksum(skb, start,

						  skb->len - start, ~(__u32)0,

						  crc32c_csum_stub));

	*(__le32 *)(skb->data + offset) = crc32c_csum;

	skb->ip_summed = CHECKSUM_NONE;

out:

	return ret;

}



__be16 skb_network_protocol(struct sk_buff *skb, int *depth)

{

	__be16 type = skb->protocol;

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