net: introduce and use custom sockopt socket flag

We will soon introduce custom setsockopt for UDP sockets, too.
Instead of doing even more complex arbitrary checks inside
sock_use_custom_sol_socket(), add a new socket flag and set it
for the relevant socket types (currently only MPTCP).

Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/net.h b/include/linux/net.h
index 711c359..59350fd 100644 (file)
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -41,6 +41,7 @@ struct net;
 #define SOCK_NOSPACE           2
 #define SOCK_PASSCRED          3
 #define SOCK_PASSSEC           4
+#define SOCK_CUSTOM_SOCKOPT    5
 
 #ifndef ARCH_HAS_SOCKET_TYPES
 /**

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 2e16c89..e60d144 100644 (file)
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2708,6 +2708,8 @@ static int mptcp_init_sock(struct sock *sk)
        if (ret)
                return ret;
 
+       set_bit(SOCK_CUSTOM_SOCKOPT, &sk->sk_socket->flags);
+
        /* fetch the ca name; do it outside __mptcp_init_sock(), so that clone will
         * propagate the correct value
         */
@@ -3684,6 +3686,8 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
                struct mptcp_subflow_context *subflow;
                struct sock *newsk = newsock->sk;
 
+               set_bit(SOCK_CUSTOM_SOCKOPT, &newsock->flags);
+
                lock_sock(newsk);
 
                /* PM/worker can now acquire the first subflow socket

diff --git a/net/socket.c b/net/socket.c
index 00da9ce..55c5d53 100644 (file)
--- a/net/socket.c
+++ b/net/socket.c
@@ -2199,13 +2199,7 @@ SYSCALL_DEFINE4(recv, int, fd, void __user *, ubuf, size_t, size,
 
 static bool sock_use_custom_sol_socket(const struct socket *sock)
 {
-       const struct sock *sk = sock->sk;
-
-       /* Use sock->ops->setsockopt() for MPTCP */
-       return IS_ENABLED(CONFIG_MPTCP) &&
-              sk->sk_protocol == IPPROTO_MPTCP &&
-              sk->sk_type == SOCK_STREAM &&
-              (sk->sk_family == AF_INET || sk->sk_family == AF_INET6);
+       return test_bit(SOCK_CUSTOM_SOCKOPT, &sock->flags);
 }
 
 /*