mptcp: restrict values of 'enabled' sysctl

To avoid confusions, it seems better to parse this sysctl parameter as a
boolean. We use it as a boolean, no need to parse an integer and bring
confusions if we see a value different from 0 and 1, especially with
this parameter name: enabled.

It seems fine to do this modification because the default value is 1
(enabled). Then the only other interesting value to set is 0 (disabled).
All other values would not have changed the default behaviour.

Suggested-by: Florian Westphal <fw@strlen.de>
Acked-by: Florian Westphal <fw@strlen.de>
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>

diff --git a/Documentation/networking/mptcp-sysctl.rst b/Documentation/networking/mptcp-sysctl.rst
index 6af0196..3b352e5 100644 (file)
--- a/Documentation/networking/mptcp-sysctl.rst
+++ b/Documentation/networking/mptcp-sysctl.rst
@@ -7,13 +7,13 @@ MPTCP Sysfs variables
 /proc/sys/net/mptcp/* Variables
 ===============================
 
-enabled - INTEGER
+enabled - BOOLEAN
        Control whether MPTCP sockets can be created.
 
-       MPTCP sockets can be created if the value is nonzero. This is
-       a per-namespace sysctl.
+       MPTCP sockets can be created if the value is 1. This is a
+       per-namespace sysctl.
 
-       Default: 1
+       Default: 1 (enabled)
 
 add_addr_timeout - INTEGER (seconds)
        Set the timeout after which an ADD_ADDR control message will be

diff --git a/net/mptcp/ctrl.c b/net/mptcp/ctrl.c
index a3b15ed..1ec4d36 100644 (file)
--- a/net/mptcp/ctrl.c
+++ b/net/mptcp/ctrl.c
@@ -21,7 +21,7 @@ struct mptcp_pernet {
        struct ctl_table_header *ctl_table_hdr;
 #endif
 
-       int mptcp_enabled;
+       u8 mptcp_enabled;
        unsigned int add_addr_timeout;
 };
 
@@ -50,12 +50,14 @@ static void mptcp_pernet_set_defaults(struct mptcp_pernet *pernet)
 static struct ctl_table mptcp_sysctl_table[] = {
        {
                .procname = "enabled",
-               .maxlen = sizeof(int),
+               .maxlen = sizeof(u8),
                .mode = 0644,
                /* users with CAP_NET_ADMIN or root (not and) can change this
                 * value, same as other sysctl or the 'net' tree.
                 */
-               .proc_handler = proc_dointvec,
+               .proc_handler = proc_dou8vec_minmax,
+               .extra1       = SYSCTL_ZERO,
+               .extra2       = SYSCTL_ONE
        },
        {
                .procname = "add_addr_timeout",