Subject: [PATCH v1 net-next 09/14] udp: Don't pass proto to udp[46]_csum_init().

From: Kuniyuki Iwashima <[email-masked]>
Date: Mon, 29 May 2023 18:03:43 -0700

We passed IPPROTO_UDPLITE as proto to __udp[46]_lib_rcv(), which passes
it to udp[46]_csum_init().

However, we no longer call __udp[46]_lib_rcv() with IPPROTO_UDPLITE, so
proto is always IPPROTO_UDP in udp[46]_csum_init(), and we can hard-code
it.

Also, udp6_csum_init() is not called from other functions, so we move it
to net/ipv6/udp.c as a static function.

Signed-off-by: Kuniyuki Iwashima <[email-masked]>
---
 include/net/ip6_checksum.h |  1 -
 net/ipv4/udp.c             |  7 +++----
 net/ipv6/ip6_checksum.c    | 33 ---------------------------------
 net/ipv6/udp.c             | 34 +++++++++++++++++++++++++++++++++-
 4 files changed, 36 insertions(+), 39 deletions(-)

diff --git a/include/net/ip6_checksum.h b/include/net/ip6_checksum.h
index c8a96b888277..f9e03cc7a19c 100644
--- a/include/net/ip6_checksum.h
+++ b/include/net/ip6_checksum.h
@@ -83,5 +83,4 @@ void udp6_set_csum(bool nocheck, struct sk_buff *skb,
 		   const struct in6_addr *saddr,
 		   const struct in6_addr *daddr, int len);
 
-int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh, int proto);
 #endif
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index aee075fb5f4f..f8a545c6e3e7 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2247,15 +2247,14 @@ static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
  * Otherwise, csum completion requires checksumming packet body,
  * including udp header and folding it to skb->csum.
  */
-static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh,
-				 int proto)
+static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh)
 {
 	int err;
 
 	/* Note, we are only interested in != 0 or == 0, thus the
 	 * force to int.
 	 */
-	err = (__force int)skb_checksum_init_zero_check(skb, proto, uh->check,
+	err = (__force int)skb_checksum_init_zero_check(skb, IPPROTO_UDP, uh->check,
 							inet_compute_pseudo);
 	if (err)
 		return err;
@@ -2335,7 +2334,7 @@ static int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 		uh = udp_hdr(skb);
 	}
 
-	if (udp4_csum_init(skb, uh, proto))
+	if (udp4_csum_init(skb, uh))
 		goto csum_error;
 
 	sk = skb_steal_sock(skb, &refcounted);
diff --git a/net/ipv6/ip6_checksum.c b/net/ipv6/ip6_checksum.c
index 1362db7a3660..e1a594873675 100644
--- a/net/ipv6/ip6_checksum.c
+++ b/net/ipv6/ip6_checksum.c
@@ -62,39 +62,6 @@ __sum16 csum_ipv6_magic(const struct in6_addr *saddr,
 EXPORT_SYMBOL(csum_ipv6_magic);
 #endif
 
-int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh, int proto)
-{
-	int err;
-
-	/* To support RFC 6936 (allow zero checksum in UDP/IPV6 for tunnels)
-	 * we accept a checksum of zero here. When we find the socket
-	 * for the UDP packet we'll check if that socket allows zero checksum
-	 * for IPv6 (set by socket option).
-	 *
-	 * Note, we are only interested in != 0 or == 0, thus the
-	 * force to int.
-	 */
-	err = (__force int)skb_checksum_init_zero_check(skb, proto, uh->check,
-							ip6_compute_pseudo);
-	if (err)
-		return err;
-
-	if (skb->ip_summed == CHECKSUM_COMPLETE && !skb->csum_valid) {
-		/* If SW calculated the value, we know it's bad */
-		if (skb->csum_complete_sw)
-			return 1;
-
-		/* HW says the value is bad. Let's validate that.
-		 * skb->csum is no longer the full packet checksum,
-		 * so don't treat is as such.
-		 */
-		skb_checksum_complete_unset(skb);
-	}
-
-	return 0;
-}
-EXPORT_SYMBOL(udp6_csum_init);
-
 /* Function to set UDP checksum for an IPv6 UDP packet. This is intended
  * for the simple case like when setting the checksum for a UDP tunnel.
  */
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 21d48f8803d0..170bbaa4a9d4 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -896,6 +896,38 @@ static void udp6_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst)
 	}
 }
 
+static int udp6_csum_init(struct sk_buff *skb, struct udphdr *uh)
+{
+	int err;
+
+	/* To support RFC 6936 (allow zero checksum in UDP/IPV6 for tunnels)
+	 * we accept a checksum of zero here. When we find the socket
+	 * for the UDP packet we'll check if that socket allows zero checksum
+	 * for IPv6 (set by socket option).
+	 *
+	 * Note, we are only interested in != 0 or == 0, thus the
+	 * force to int.
+	 */
+	err = (__force int)skb_checksum_init_zero_check(skb, IPPROTO_UDP, uh->check,
+							ip6_compute_pseudo);
+	if (err)
+		return err;
+
+	if (skb->ip_summed == CHECKSUM_COMPLETE && !skb->csum_valid) {
+		/* If SW calculated the value, we know it's bad */
+		if (skb->csum_complete_sw)
+			return 1;
+
+		/* HW says the value is bad. Let's validate that.
+		 * skb->csum is no longer the full packet checksum,
+		 * so don't treat is as such.
+		 */
+		skb_checksum_complete_unset(skb);
+	}
+
+	return 0;
+}
+
 /* wrapper for udp_queue_rcv_skb tacking care of csum conversion and
  * return code conversion for ip layer consumption
  */
@@ -956,7 +988,7 @@ static int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
 		}
 	}
 
-	if (udp6_csum_init(skb, uh, proto))
+	if (udp6_csum_init(skb, uh))
 		goto csum_error;
 
 	/* Check if the socket is already available, e.g. due to early demux */
-- 
2.30.2