tcp: fix ipv4 mapped request socks

ss should display ipv4 mapped request sockets like this :

tcp    SYN-RECV   0      0  ::ffff:192.168.0.1:8080   ::ffff:192.0.2.1:35261

and not like this :

tcp    SYN-RECV   0      0  192.168.0.1:8080   192.0.2.1:35261

We should init ireq->ireq_family based on listener sk_family,
not the actual protocol carried by SYN packet.

This means we can set ireq_family in inet_reqsk_alloc()

Fixes: 3f66b083a5b7 ("inet: introduce ireq_family")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/syncookies.c

@@ -347,7 +347,6 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb)
 	req->ts_recent		= tcp_opt.saw_tstamp ? tcp_opt.rcv_tsval : 0;
 	treq->snt_synack	= tcp_opt.saw_tstamp ? tcp_opt.rcv_tsecr : 0;
 	treq->tfo_listener	= false;
-	ireq->ireq_family = AF_INET;
 
 	ireq->ir_iif = sk->sk_bound_dev_if;
 

net/ipv4/tcp_input.c

@@ -5980,7 +5980,7 @@ struct request_sock *inet_reqsk_alloc(const struct request_sock_ops *ops,
 		atomic64_set(&ireq->ir_cookie, 0);
 		ireq->ireq_state = TCP_NEW_SYN_RECV;
 		write_pnet(&ireq->ireq_net, sock_net(sk_listener));
-
+		ireq->ireq_family = sk_listener->sk_family;
 	}
 
 	return req;

net/ipv4/tcp_ipv4.c

@@ -1206,7 +1206,6 @@ static void tcp_v4_init_req(struct request_sock *req, struct sock *sk_listener,
 	sk_daddr_set(req_to_sk(req), ip_hdr(skb)->saddr);
 	ireq->no_srccheck = inet_sk(sk_listener)->transparent;
 	ireq->opt = tcp_v4_save_options(skb);
-	ireq->ireq_family = AF_INET;
 }
 
 static struct dst_entry *tcp_v4_route_req(struct sock *sk, struct flowi *fl,

net/ipv6/syncookies.c

@@ -197,7 +197,6 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb)
 	ireq = inet_rsk(req);
 	treq = tcp_rsk(req);
 	treq->tfo_listener = false;
-	ireq->ireq_family = AF_INET6;
 
 	if (security_inet_conn_request(sk, skb, req))
 		goto out_free;

net/ipv6/tcp_ipv6.c

@@ -688,7 +688,6 @@ static void tcp_v6_init_req(struct request_sock *req, struct sock *sk,
 		atomic_inc(&skb->users);
 		ireq->pktopts = skb;
 	}
-	ireq->ireq_family = AF_INET6;
 }
 
 static struct dst_entry *tcp_v6_route_req(struct sock *sk, struct flowi *fl,