mptcp: remove MPTCP 'ifdef' in TCP SYN cookies

commit 3fff88186f047627bb128d65155f42517f8e448f upstream.

To ease the maintenance, it is often recommended to avoid having #ifdef
preprocessor conditions.

Here the section related to CONFIG_MPTCP was quite short but the next
commit needs to add more code around. It is then cleaner to move
specific MPTCP code to functions located in net/mptcp directory.

Now that mptcp_subflow_request_sock_ops structure can be static, it can
also be marked as "read only after init".

Suggested-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index 412479e..3c5c686 100644 (file)
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -97,8 +97,6 @@ struct mptcp_out_options {
 };
 
 #ifdef CONFIG_MPTCP
-extern struct request_sock_ops mptcp_subflow_request_sock_ops;
-
 void mptcp_init(void);
 
 static inline bool sk_is_mptcp(const struct sock *sk)
@@ -188,6 +186,9 @@ void mptcp_seq_show(struct seq_file *seq);
 int mptcp_subflow_init_cookie_req(struct request_sock *req,
                                  const struct sock *sk_listener,
                                  struct sk_buff *skb);
+struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
+                                              struct sock *sk_listener,
+                                              bool attach_listener);
 
 __be32 mptcp_get_reset_option(const struct sk_buff *skb);
 
@@ -274,6 +275,13 @@ static inline int mptcp_subflow_init_cookie_req(struct request_sock *req,
        return 0; /* TCP fallback */
 }
 
+static inline struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
+                                                            struct sock *sk_listener,
+                                                            bool attach_listener)
+{
+       return NULL;
+}
+
 static inline __be32 mptcp_reset_option(const struct sk_buff *skb)  { return htonl(0u); }
 #endif /* CONFIG_MPTCP */
 

diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c
index 942d2df..26fb97d 100644 (file)
--- a/net/ipv4/syncookies.c
+++ b/net/ipv4/syncookies.c
@@ -288,12 +288,11 @@ struct request_sock *cookie_tcp_reqsk_alloc(const struct request_sock_ops *ops,
        struct tcp_request_sock *treq;
        struct request_sock *req;
 
-#ifdef CONFIG_MPTCP
        if (sk_is_mptcp(sk))
-               ops = &mptcp_subflow_request_sock_ops;
-#endif
+               req = mptcp_subflow_reqsk_alloc(ops, sk, false);
+       else
+               req = inet_reqsk_alloc(ops, sk, false);
 
-       req = inet_reqsk_alloc(ops, sk, false);
        if (!req)
                return NULL;
 

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 2159b5f..3f670f2 100644 (file)
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -529,7 +529,7 @@ static int subflow_v6_rebuild_header(struct sock *sk)
 }
 #endif
 
-struct request_sock_ops mptcp_subflow_request_sock_ops;
+static struct request_sock_ops mptcp_subflow_request_sock_ops __ro_after_init;
 static struct tcp_request_sock_ops subflow_request_sock_ipv4_ops __ro_after_init;
 
 static int subflow_v4_conn_request(struct sock *sk, struct sk_buff *skb)
@@ -582,6 +582,16 @@ drop:
 }
 #endif
 
+struct request_sock *mptcp_subflow_reqsk_alloc(const struct request_sock_ops *ops,
+                                              struct sock *sk_listener,
+                                              bool attach_listener)
+{
+       ops = &mptcp_subflow_request_sock_ops;
+
+       return inet_reqsk_alloc(ops, sk_listener, attach_listener);
+}
+EXPORT_SYMBOL(mptcp_subflow_reqsk_alloc);
+
 /* validate hmac received in third ACK */
 static bool subflow_hmac_valid(const struct request_sock *req,
                               const struct mptcp_options_received *mp_opt)