[PATCH net-next 01/10] net: introduce CONFIG_NET_CRC32C

Eric Biggers
2025-05-11T00:41:29Z

From: Eric Biggers <ebiggers@google.com>

Add a hidden kconfig symbol NET_CRC32C that will group together the
functions that calculate CRC32C checksums of packets, so that these
don't have to be built into NET-enabled kernels that don't need them.

Make skb_crc32c_csum_help() (which is called only when IP_SCTP is
enabled) conditional on this symbol, and make IP_SCTP select it.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
net/Kconfig | 4 ++++
net/core/dev.c | 2 ++
net/sctp/Kconfig | 1 +
3 files changed, 7 insertions(+)

diff --git a/net/Kconfig b/net/Kconfig
index 202cc595e5e6..5b71a52987d3 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -73,10 +73,14 @@ config NET_DEVMEM
depends on PAGE_POOL

config NET_SHAPER
bool

+config NET_CRC32C
+ bool
+ select CRC32
+
menu "Networking options"

source "net/packet/Kconfig"
source "net/unix/Kconfig"
source "net/tls/Kconfig"
diff --git a/net/core/dev.c b/net/core/dev.c
index c9013632296f..51606b2d17bb 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3592,10 +3592,11 @@ int skb_checksum_help(struct sk_buff *skb)
out:
return ret;
}
EXPORT_SYMBOL(skb_checksum_help);

+#ifdef CONFIG_NET_CRC32C
int skb_crc32c_csum_help(struct sk_buff *skb)
{
__le32 crc32c_csum;
int ret = 0, offset, start;

@@ -3631,10 +3632,11 @@ int skb_crc32c_csum_help(struct sk_buff *skb)
skb_reset_csum_not_inet(skb);
out:
return ret;
}
EXPORT_SYMBOL(skb_crc32c_csum_help);
+#endif /* CONFIG_NET_CRC32C */

__be16 skb_network_protocol(struct sk_buff *skb, int *depth)
{
__be16 type = skb->protocol;

diff --git a/net/sctp/Kconfig b/net/sctp/Kconfig
index d18a72df3654..3669ba351856 100644
--- a/net/sctp/Kconfig
+++ b/net/sctp/Kconfig
@@ -9,10 +9,11 @@ menuconfig IP_SCTP
depends on IPV6 || IPV6=n
select CRC32
select CRYPTO
select CRYPTO_HMAC
select CRYPTO_SHA1
+ select NET_CRC32C
select NET_UDP_TUNNEL
help
Stream Control Transmission Protocol

From RFC 2960 <http://www.ietf.org/rfc/rfc2960.txt>.

base-commit: 0b28182c73a3d013bcabbb890dc1070a8388f55a
--
2.49.0