tcp: get rid of twsk_unique()

DCCP is going away soon, and had no twsk_unique() method.

We can directly call tcp_twsk_unique() for TCP sockets.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240507164140.940547-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: edumazet

include/net/timewait_sock.h

@@ -15,18 +15,9 @@ struct timewait_sock_ops {
 	struct kmem_cache	*twsk_slab;
 	char		*twsk_slab_name;
 	unsigned int	twsk_obj_size;
-	int		(*twsk_unique)(struct sock *sk,
-				       struct sock *sktw, void *twp);
 	void		(*twsk_destructor)(struct sock *sk);
 };
 
-static inline int twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
-{
-	if (sk->sk_prot->twsk_prot->twsk_unique != NULL)
-		return sk->sk_prot->twsk_prot->twsk_unique(sk, sktw, twp);
-	return 0;
-}
-
 static inline void twsk_destructor(struct sock *sk)
 {
 	if (sk->sk_prot->twsk_prot->twsk_destructor != NULL)

net/ipv4/inet_hashtables.c

@@ -565,7 +565,8 @@ static int __inet_check_established(struct inet_timewait_death_row *death_row,
 		if (likely(inet_match(net, sk2, acookie, ports, dif, sdif))) {
 			if (sk2->sk_state == TCP_TIME_WAIT) {
 				tw = inet_twsk(sk2);
-				if (twsk_unique(sk, sk2, twp))
+				if (sk->sk_protocol == IPPROTO_TCP &&
+				    tcp_twsk_unique(sk, sk2, twp))
 					break;
 			}
 			goto not_unique;

net/ipv4/tcp_ipv4.c

@@ -2437,7 +2437,6 @@ int tcp_v4_rcv(struct sk_buff *skb)
 
 static struct timewait_sock_ops tcp_timewait_sock_ops = {
 	.twsk_obj_size	= sizeof(struct tcp_timewait_sock),
-	.twsk_unique	= tcp_twsk_unique,
 	.twsk_destructor= tcp_twsk_destructor,
 };
 

net/ipv6/inet6_hashtables.c

@@ -21,6 +21,7 @@
 #include <net/secure_seq.h>
 #include <net/ip.h>
 #include <net/sock_reuseport.h>
+#include <net/tcp.h>
 
 u32 inet6_ehashfn(const struct net *net,
 		  const struct in6_addr *laddr, const u16 lport,
@@ -289,7 +290,8 @@ static int __inet6_check_established(struct inet_timewait_death_row *death_row,
 				       dif, sdif))) {
 			if (sk2->sk_state == TCP_TIME_WAIT) {
 				tw = inet_twsk(sk2);
-				if (twsk_unique(sk, sk2, twp))
+				if (sk->sk_protocol == IPPROTO_TCP &&
+				    tcp_twsk_unique(sk, sk2, twp))
 					break;
 			}
 			goto not_unique;

net/ipv6/tcp_ipv6.c

@@ -2049,7 +2049,6 @@ void tcp_v6_early_demux(struct sk_buff *skb)
 
 static struct timewait_sock_ops tcp6_timewait_sock_ops = {
 	.twsk_obj_size	= sizeof(struct tcp6_timewait_sock),
-	.twsk_unique	= tcp_twsk_unique,
 	.twsk_destructor = tcp_twsk_destructor,
 };