Subject: [PATCH net-next 2/5] net: skbuff: hide csum_not_inet when CONFIG_IP_SCTP not set

From: Jakub Kicinski <[email-masked]>
Date: Fri, 14 Apr 2023 09:01:02 -0700

SCTP is not universally deployed, allow hiding its bit
from the skb.

Signed-off-by: Jakub Kicinski <[email-masked]>
---
 include/linux/skbuff.h | 14 ++++++++++++++
 net/core/dev.c         |  3 +--
 net/sched/act_csum.c   |  3 +--
 3 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 7160101edc8a..45c3044e8123 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -983,7 +983,9 @@ struct sk_buff {
 	__u8			decrypted:1;
 #endif
 	__u8			slow_gro:1;
+#if IS_ENABLED(CONFIG_IP_SCTP)
 	__u8			csum_not_inet:1;
+#endif
 
 #ifdef CONFIG_NET_SCHED
 	__u16			tc_index;	/* traffic control index */
@@ -5054,7 +5056,19 @@ static inline void skb_reset_redirect(struct sk_buff *skb)
 
 static inline bool skb_csum_is_sctp(struct sk_buff *skb)
 {
+#if IS_ENABLED(CONFIG_IP_SCTP)
 	return skb->csum_not_inet;
+#else
+	return 0;
+#endif
+}
+
+static inline void skb_reset_csum_not_inet(struct sk_buff *skb)
+{
+	skb->ip_summed = CHECKSUM_NONE;
+#if IS_ENABLED(CONFIG_IP_SCTP)
+	skb->csum_not_inet = 0;
+#endif
 }
 
 static inline void skb_set_kcov_handle(struct sk_buff *skb,
diff --git a/net/core/dev.c b/net/core/dev.c
index c7f13742b56c..177e91819850 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3315,8 +3315,7 @@ int skb_crc32c_csum_help(struct sk_buff *skb)
 						  skb->len - start, ~(__u32)0,
 						  crc32c_csum_stub));
 	*(__le32 *)(skb->data + offset) = crc32c_csum;
-	skb->ip_summed = CHECKSUM_NONE;
-	skb->csum_not_inet = 0;
+	skb_reset_csum_not_inet(skb);
 out:
 	return ret;
 }
diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c
index 95e9304024b7..8ed285023a40 100644
--- a/net/sched/act_csum.c
+++ b/net/sched/act_csum.c
@@ -376,8 +376,7 @@ static int tcf_csum_sctp(struct sk_buff *skb, unsigned int ihl,
 
 	sctph->checksum = sctp_compute_cksum(skb,
 					     skb_network_offset(skb) + ihl);
-	skb->ip_summed = CHECKSUM_NONE;
-	skb->csum_not_inet = 0;
+	skb_reset_csum_not_inet(skb);
 
 	return 1;
 }
-- 
2.39.2