ksmbd: extend the existing connection limiting mechanism to support IPv6

Update the connection tracking logic to handle both IPv4 and IPv6
address families.

Cc: [email protected]
Fixes: e6bb91939740 ("ksmbd: limit repeated connections from clients with the same IP")
Signed-off-by: Namjae Jeon <[email protected]>

Author: namjaejeon

connection.h

@@ -46,7 +46,10 @@ struct ksmbd_conn {
 	struct mutex			srv_mutex;
 	int				status;
 	unsigned int			cli_cap;
-	__be32				inet_addr;
+	union {
+		__be32			inet_addr;
+		u8			inet6_addr[16];
+	};
 	char				*request_buf;
 	struct ksmbd_transport		*transport;
 	struct nls_table		*local_nls;

transport_tcp.c

@@ -115,7 +115,10 @@ static struct tcp_transport *alloc_transport(struct socket *client_sk)
 		return NULL;
 	}
 
-	conn->inet_addr = inet_sk(client_sk->sk)->inet_daddr;
+	if (client_sk->sk->sk_family == AF_INET6)
+		memcpy(&conn->inet6_addr, &client_sk->sk->sk_v6_daddr, 16);
+	else
+		conn->inet_addr = inet_sk(client_sk->sk)->inet_daddr;
 	conn->transport = KSMBD_TRANS(t);
 	KSMBD_TRANS(t)->conn = conn;
 	KSMBD_TRANS(t)->ops = &ksmbd_tcp_transport_ops;
@@ -259,7 +262,6 @@ static int ksmbd_kthread_fn(void *p)
 {
 	struct socket *client_sk = NULL;
 	struct interface *iface = (struct interface *)p;
-	struct inet_sock *csk_inet;
 	struct ksmbd_conn *conn;
 	int ret;
 
@@ -282,10 +284,16 @@ static int ksmbd_kthread_fn(void *p)
 		/*
 		 * Limits repeated connections from clients with the same IP.
 		 */
-		csk_inet = inet_sk(client_sk->sk);
 		down_read(&conn_list_lock);
 		list_for_each_entry(conn, &conn_list, conns_list)
-			if (csk_inet->inet_daddr == conn->inet_addr) {
+			if (client_sk->sk->sk_family == AF_INET6) {
+				if (memcmp(&client_sk->sk->sk_v6_daddr,
+					   &conn->inet6_addr, 16) == 0) {
+					ret = -EAGAIN;
+					break;
+				}
+			} else if (inet_sk(client_sk->sk)->inet_daddr ==
+				 conn->inet_addr) {
 				ret = -EAGAIN;
 				break;
 			}