[PATCH net-next 05/10] sctp: use skb_crc32c() instead of __skb_checksum()

Eric Biggers
2025-05-11T00:41:34Z

From: Eric Biggers <ebiggers@google.com>

Make sctp_compute_cksum() just use the new function skb_crc32c(),
instead of calling __skb_checksum() with a skb_checksum_ops struct that
does CRC32C. This is faster and simpler.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
include/net/sctp/checksum.h | 29 +++--------------------------
net/netfilter/Kconfig | 4 ++--
net/netfilter/ipvs/Kconfig | 2 +-
net/openvswitch/Kconfig | 2 +-
net/sched/Kconfig | 2 +-
net/sctp/Kconfig | 1 -
net/sctp/offload.c | 1 -
7 files changed, 8 insertions(+), 33 deletions(-)

diff --git a/include/net/sctp/checksum.h b/include/net/sctp/checksum.h
index 291465c25810..654d37ec0402 100644
--- a/include/net/sctp/checksum.h
+++ b/include/net/sctp/checksum.h
@@ -13,51 +13,28 @@
*
* Written or modified by:
* Dinakaran Joseph
* Jon Grimm <jgrimm@us.ibm.com>
* Sridhar Samudrala <sri@us.ibm.com>
- *
- * Rewritten to use libcrc32c by:
* Vlad Yasevich <vladislav.yasevich@hp.com>
*/

#ifndef __sctp_checksum_h__
#define __sctp_checksum_h__

#include <linux/types.h>
#include <linux/sctp.h>
-#include <linux/crc32c.h>
-#include <linux/crc32.h>
-
-static inline __wsum sctp_csum_update(const void *buff, int len, __wsum sum)
-{
- return (__force __wsum)crc32c((__force __u32)sum, buff, len);
-}
-
-static inline __wsum sctp_csum_combine(__wsum csum, __wsum csum2,
- int offset, int len)
-{
- return (__force __wsum)crc32c_combine((__force __u32)csum,
- (__force __u32)csum2, len);
-}
-
-static const struct skb_checksum_ops sctp_csum_ops = {
- .update = sctp_csum_update,
- .combine = sctp_csum_combine,
-};

static inline __le32 sctp_compute_cksum(const struct sk_buff *skb,
unsigned int offset)
{
struct sctphdr *sh = (struct sctphdr *)(skb->data + offset);
__le32 old = sh->checksum;
- __wsum new;
+ u32 new;

sh->checksum = 0;
- new = ~__skb_checksum(skb, offset, skb->len - offset, ~(__wsum)0,
- &sctp_csum_ops);
+ new = ~skb_crc32c(skb, offset, skb->len - offset, ~0);
sh->checksum = old;
-
- return cpu_to_le32((__force __u32)new);
+ return cpu_to_le32(new);
}

#endif /* __sctp_checksum_h__ */
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index 3b2183fc7e56..2560416218d0 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -210,11 +210,11 @@ config NF_CT_PROTO_GRE

config NF_CT_PROTO_SCTP
bool 'SCTP protocol connection tracking support'
depends on NETFILTER_ADVANCED
default y
- select CRC32
+ select NET_CRC32C
help
With this option enabled, the layer 3 independent connection
tracking code will be able to do state tracking on SCTP connections.

If unsure, say Y.
@@ -473,11 +473,11 @@ config NETFILTER_SYNPROXY

endif # NF_CONNTRACK

config NF_TABLES
select NETFILTER_NETLINK
- select CRC32
+ select NET_CRC32C
tristate "Netfilter nf_tables support"
help
nftables is the new packet classification framework that intends to
replace the existing {ip,ip6,arp,eb}_tables infrastructure. It
provides a pseudo-state machine with an extensible instruction-set
diff --git a/net/netfilter/ipvs/Kconfig b/net/netfilter/ipvs/Kconfig
index 8c5b1fe12d07..c203252e856d 100644
--- a/net/netfilter/ipvs/Kconfig
+++ b/net/netfilter/ipvs/Kconfig
@@ -103,11 +103,11 @@ config IP_VS_PROTO_AH
This option enables support for load balancing AH (Authentication
Header) transport protocol. Say Y if unsure.

config IP_VS_PROTO_SCTP
bool "SCTP load balancing support"
- select CRC32
+ select NET_CRC32C
help
This option enables support for load balancing SCTP transport
protocol. Say Y if unsure.

comment "IPVS scheduler"
diff --git a/net/openvswitch/Kconfig b/net/openvswitch/Kconfig
index 5481bd561eb4..e6aaee92dba4 100644
--- a/net/openvswitch/Kconfig
+++ b/net/openvswitch/Kconfig
@@ -9,12 +9,12 @@ config OPENVSWITCH
depends on !NF_CONNTRACK || \
(NF_CONNTRACK && ((!NF_DEFRAG_IPV6 || NF_DEFRAG_IPV6) && \
(!NF_NAT || NF_NAT) && \
(!NETFILTER_CONNCOUNT || NETFILTER_CONNCOUNT)))
depends on PSAMPLE || !PSAMPLE
- select CRC32
select MPLS
+ select NET_CRC32C
select NET_MPLS_GSO
select DST_CACHE
select NET_NSH
select NF_CONNTRACK_OVS if NF_CONNTRACK
select NF_NAT_OVS if NF_NAT
diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index 9f0b3f943fca..ad914d2b2e22 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -794,11 +794,11 @@ config NET_ACT_SKBEDIT
module will be called act_skbedit.

config NET_ACT_CSUM
tristate "Checksum Updating"
depends on NET_CLS_ACT && INET
- select CRC32
+ select NET_CRC32C
help
Say Y here to update some common checksum after some direct
packet alterations.

To compile this code as a module, choose M here: the
diff --git a/net/sctp/Kconfig b/net/sctp/Kconfig
index 3669ba351856..24d5a35ce894 100644
--- a/net/sctp/Kconfig
+++ b/net/sctp/Kconfig
@@ -5,11 +5,10 @@

menuconfig IP_SCTP
tristate "The SCTP Protocol"
depends on INET
depends on IPV6 || IPV6=n
- select CRC32
select CRYPTO
select CRYPTO_HMAC
select CRYPTO_SHA1
select NET_CRC32C
select NET_UDP_TUNNEL
diff --git a/net/sctp/offload.c b/net/sctp/offload.c
index 502095173d88..e6f863c031b4 100644
--- a/net/sctp/offload.c
+++ b/net/sctp/offload.c
@@ -109,11 +109,10 @@ int __init sctp_offload_init(void)

ret = inet6_add_offload(&sctp6_offload, IPPROTO_SCTP);
if (ret)
goto ipv4;

- crc32c_csum_stub = &sctp_csum_ops;
return ret;

ipv4:
inet_del_offload(&sctp_offload, IPPROTO_SCTP);
out:
--
2.49.0