commit 7b58e63e744cbcdeafe0a52423014fd9c9f7e346
author Eric Dumazet <edumazet@google.com> Mon Nov 09 15:13:49 2020 -0800
committer Jakub Kicinski <kuba@kernel.org> Tue Nov 10 17:57:14 2020 -0800
tree 9f9b4e2c1bc9dac9e1053805d90e1baf5ce09339
parent d6bb2d1e86903d3fbf895752ac2c0c2465534579

inet: udp{4|6}_lib_lookup_skb() skb argument is const

The skb is needed only to fetch the keys for the lookup.

Both functions are used from GRO stack, we do not want
accidental modification of the skb.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Alexander Lobakin <alobakin@pm.me>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/udp.h

diff --git a/include/net/udp.h b/include/net/udp.h
index 295d52a..877832b 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -164,7 +164,7 @@ static inline void udp_csum_pull_header(struct sk_buff *skb)
 	UDP_SKB_CB(skb)->cscov -= sizeof(struct udphdr);
 }
 
-typedef struct sock *(*udp_lookup_t)(struct sk_buff *skb, __be16 sport,
+typedef struct sock *(*udp_lookup_t)(const struct sk_buff *skb, __be16 sport,
 				     __be16 dport);
 
 INDIRECT_CALLABLE_DECLARE(struct sk_buff *udp4_gro_receive(struct list_head *,
@@ -313,7 +313,7 @@ struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
 			       __be32 daddr, __be16 dport, int dif, int sdif,
 			       struct udp_table *tbl, struct sk_buff *skb);
-struct sock *udp4_lib_lookup_skb(struct sk_buff *skb,
+struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb,
 				 __be16 sport, __be16 dport);
 struct sock *udp6_lib_lookup(struct net *net,
 			     const struct in6_addr *saddr, __be16 sport,
@@ -324,7 +324,7 @@ struct sock *__udp6_lib_lookup(struct net *net,
 			       const struct in6_addr *daddr, __be16 dport,
 			       int dif, int sdif, struct udp_table *tbl,
 			       struct sk_buff *skb);
-struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
+struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb,
 				 __be16 sport, __be16 dport);
 
 /* UDP uses skb->dev_scratch to cache as much information as possible and avoid

net/ipv4/udp.c

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 0d5cd69..c732f5a 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -541,7 +541,7 @@ static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
 				 inet_sdif(skb), udptable, skb);
 }
 
-struct sock *udp4_lib_lookup_skb(struct sk_buff *skb,
+struct sock *udp4_lib_lookup_skb(const struct sk_buff *skb,
 				 __be16 sport, __be16 dport)
 {
 	const struct iphdr *iph = ip_hdr(skb);

net/ipv6/udp.c

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 559611b..e152f80 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -276,7 +276,7 @@ static struct sock *__udp6_lib_lookup_skb(struct sk_buff *skb,
 				 inet6_sdif(skb), udptable, skb);
 }
 
-struct sock *udp6_lib_lookup_skb(struct sk_buff *skb,
+struct sock *udp6_lib_lookup_skb(const struct sk_buff *skb,
 				 __be16 sport, __be16 dport)
 {
 	const struct ipv6hdr *iph = ipv6_hdr(skb);