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From: Kuniyuki Iwashima <kuniyu@amazon•com>
To: "David S. Miller" <davem@davemloft•net>,
	Eric Dumazet <edumazet@google•com>,
	Jakub Kicinski <kuba@kernel•org>, Paolo Abeni <pabeni@redhat•com>,
	David Ahern <dsahern@kernel•org>,
	Willem de Bruijn <willemdebruijn.kernel@gmail•com>
Cc: Kuniyuki Iwashima <kuniyu@amazon•com>,
	Kuniyuki Iwashima <kuni1840@gmail•com>, <netdev@vger•kernel.org>
Subject: [PATCH v1 net-next 11/14] udp: Optimise ulen tests in __udp[46]_lib_rcv().
Date: Mon, 29 May 2023 18:03:45 -0700	[thread overview]
Message-ID: <20230530010348.21425-12-kuniyu@amazon.com> (raw)
In-Reply-To: <20230530010348.21425-1-kuniyu@amazon.com>

In __udp4_lib_rcv(), we need not call udp_hdr() unless we call
pskb_trim_rcsum().

In __udp6_lib_rcv(), we can save two unneeded conditions for every
jumbo payload that never be true.

	if (ulen > skb->len)
		goto short_packet;
	if (ulen == 0)
		ulen = skb->len;
	if (ulen < skb->len)

Note the number of tests for non-jumbo IPv6 payload is not changed.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon•com>
---
 net/ipv4/udp.c |  8 +++++---
 net/ipv6/udp.c | 30 +++++++++++++++++-------------
 2 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 23ebea2b84e4..eb968d20d5a8 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2325,10 +2325,12 @@ static int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable)
 	if (ulen > skb->len)
 		goto short_packet;
 
-	if (ulen < sizeof(*uh) || pskb_trim_rcsum(skb, ulen))
-		goto short_packet;
+	if (ulen < sizeof(*uh)) {
+		if (pskb_trim_rcsum(skb, ulen))
+			goto short_packet;
 
-	uh = udp_hdr(skb);
+		uh = udp_hdr(skb);
+	}
 
 	if (udp4_csum_init(skb, uh))
 		goto csum_error;
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index ee859679427a..6f5c29af4157 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -966,23 +966,27 @@ static int __udp6_lib_rcv(struct sk_buff *skb, struct udp_table *udptable)
 	uh = udp_hdr(skb);
 
 	ulen = ntohs(uh->len);
-	if (ulen > skb->len)
-		goto short_packet;
+	if (ulen) {
+		if (ulen > skb->len)
+			goto short_packet;
 
-	/* Check for jumbo payload */
-	if (ulen == 0)
-		ulen = skb->len;
+		if (ulen < sizeof(*uh))
+			goto short_packet;
 
-	if (ulen < sizeof(*uh))
-		goto short_packet;
+		if (ulen < skb->len) {
+			if (pskb_trim_rcsum(skb, ulen))
+				goto short_packet;
 
-	if (ulen < skb->len) {
-		if (pskb_trim_rcsum(skb, ulen))
-			goto short_packet;
+			saddr = &ipv6_hdr(skb)->saddr;
+			daddr = &ipv6_hdr(skb)->daddr;
+			uh = udp_hdr(skb);
+		}
+	} else {
+		/* jumbo payload */
+		ulen = skb->len;
 
-		saddr = &ipv6_hdr(skb)->saddr;
-		daddr = &ipv6_hdr(skb)->daddr;
-		uh = udp_hdr(skb);
+		if (ulen < sizeof(*uh))
+			goto short_packet;
 	}
 
 	if (udp6_csum_init(skb, uh))
-- 
2.30.2


  parent reply	other threads:[~2023-05-30  1:09 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-30  1:03 [PATCH v1 net-next 00/14] udp: Farewell to UDP-Lite Kuniyuki Iwashima
2023-05-30  1:03 ` [PATCH v1 net-next 01/14] udp: Random clenaup Kuniyuki Iwashima
2023-05-30 12:56   ` Simon Horman
2023-05-30  1:03 ` [PATCH v1 net-next 02/14] udplite: Retire UDP-Lite for IPv6 Kuniyuki Iwashima
2023-05-30 13:01   ` Simon Horman
2023-05-30 17:49     ` Kuniyuki Iwashima
2023-05-30  1:03 ` [PATCH v1 net-next 03/14] ipv6: Remove IPV6_ADDRFORM support for IPPROTO_UDPLITE Kuniyuki Iwashima
2023-05-30 14:22   ` Simon Horman
2023-05-30  1:03 ` [PATCH v1 net-next 04/14] udplite: Retire UDP-Lite for IPv4 Kuniyuki Iwashima
2023-05-30  1:03 ` [PATCH v1 net-next 05/14] udp: Remove UDP-Lite SNMP stats Kuniyuki Iwashima
2023-05-30 14:24   ` Simon Horman
2023-05-30  1:03 ` [PATCH v1 net-next 06/14] udp: Remove UDPLITE_SEND_CSCOV and UDPLITE_RECV_CSCOV Kuniyuki Iwashima
2023-05-30  1:03 ` [PATCH v1 net-next 07/14] udp: Remove pcslen, pcrlen, and pcflag in struct udp_sock Kuniyuki Iwashima
2023-05-30  1:03 ` [PATCH v1 net-next 08/14] udp: Remove csum branch for UDP-Lite Kuniyuki Iwashima
2023-05-30  1:03 ` [PATCH v1 net-next 09/14] udp: Don't pass proto to udp[46]_csum_init() Kuniyuki Iwashima
2023-05-30  1:03 ` [PATCH v1 net-next 10/14] udp: Don't pass proto to __udp[46]_lib_rcv() Kuniyuki Iwashima
2023-05-30  1:03 ` Kuniyuki Iwashima [this message]
2023-05-30  1:03 ` [PATCH v1 net-next 12/14] udp: Remove udp_table in struct proto Kuniyuki Iwashima
2023-05-30  1:03 ` [PATCH v1 net-next 13/14] udp: Remove udp_table in struct udp_seq_afinfo Kuniyuki Iwashima
2023-05-30  1:03 ` [PATCH v1 net-next 14/14] udp: Don't pass udp_table to __udp[46]_lib_lookup() Kuniyuki Iwashima
2023-05-30  2:15 ` [PATCH v1 net-next 00/14] udp: Farewell to UDP-Lite Willem de Bruijn
2023-05-30 17:34   ` Kuniyuki Iwashima
2023-05-30 20:16     ` Willem de Bruijn
2023-05-30 22:14       ` Jakub Kicinski
2023-05-31  1:01         ` Kuniyuki Iwashima
2023-05-31  4:25           ` Eric Dumazet
2023-05-31  5:10             ` Jakub Kicinski
2023-05-31  6:24               ` Paolo Abeni
2023-05-31  6:44                 ` Jakub Kicinski

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