mptcp: pm: userspace: flags: clearer msg if no remote addr

Since its introduction in commit 892f396c8e68 ("mptcp: netlink: issue
MP_PRIO signals from userspace PMs"), it was mandatory to specify the
remote address, because of the 'if (rem->addr.family == AF_UNSPEC)'
check done later one.

In theory, this attribute can be optional, but it sounds better to be
precise to avoid sending the MP_PRIO on the wrong subflow, e.g. if there
are multiple subflows attached to the same local ID. This can be relaxed
later on if there is a need to act on multiple subflows with one
command.

For the moment, the check to see if attr_rem is NULL can be removed,
because mptcp_pm_parse_entry() will do this check as well, no need to do
that differently here.

Reviewed-by: Geliang Tang <geliang@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/mptcp/pm_userspace.c b/net/mptcp/pm_userspace.c
index 4de38bc03ab8add367720262f353dd20cacac108..b6cf8ea1161ddc7f0f1662320aebfe720f55e722 100644 (file)
--- a/net/mptcp/pm_userspace.c
+++ b/net/mptcp/pm_userspace.c
@@ -580,11 +580,9 @@ int mptcp_userspace_pm_set_flags(struct sk_buff *skb, struct genl_info *info)
        if (ret < 0)
                goto set_flags_err;
 
-       if (attr_rem) {
-               ret = mptcp_pm_parse_entry(attr_rem, info, false, &rem);
-               if (ret < 0)
-                       goto set_flags_err;
-       }
+       ret = mptcp_pm_parse_entry(attr_rem, info, false, &rem);
+       if (ret < 0)
+               goto set_flags_err;
 
        if (loc.addr.family == AF_UNSPEC ||
            rem.addr.family == AF_UNSPEC) {