nexthop: Extract a helper for validation of get/del RTNL requests

Validation of messages for get / del of a next hop is the same as will be
validation of messages for get of a resilient next hop group bucket. The
difference is that policy for resilient next hop group buckets is a
superset of that used for next-hop get.

It is therefore possible to reuse the code that validates the nhmsg fields,
extracts the next-hop ID, and validates that. To that end, extract from
nh_valid_get_del_req() a helper __nh_valid_get_del_req() that does just
that.

Make the nlh argument const so that the function can be called from the
dump context, which only has a const nlh. Propagate the constness to
nh_valid_get_del_req().

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv4/nexthop.c b/net/ipv4/nexthop.c
index 9536cf2..f1c6cbd 100644 (file)
--- a/net/ipv4/nexthop.c
+++ b/net/ipv4/nexthop.c
@@ -1872,37 +1872,44 @@ static int rtm_new_nexthop(struct sk_buff *skb, struct nlmsghdr *nlh,
        return err;
 }
 
-static int nh_valid_get_del_req(struct nlmsghdr *nlh, u32 *id,
-                               struct netlink_ext_ack *extack)
+static int __nh_valid_get_del_req(const struct nlmsghdr *nlh,
+                                 struct nlattr **tb, u32 *id,
+                                 struct netlink_ext_ack *extack)
 {
        struct nhmsg *nhm = nlmsg_data(nlh);
-       struct nlattr *tb[ARRAY_SIZE(rtm_nh_policy_get)];
-       int err;
-
-       err = nlmsg_parse(nlh, sizeof(*nhm), tb,
-                         ARRAY_SIZE(rtm_nh_policy_get) - 1,
-                         rtm_nh_policy_get, extack);
-       if (err < 0)
-               return err;
 
-       err = -EINVAL;
        if (nhm->nh_protocol || nhm->resvd || nhm->nh_scope || nhm->nh_flags) {
                NL_SET_ERR_MSG(extack, "Invalid values in header");
-               goto out;
+               return -EINVAL;
        }
 
        if (!tb[NHA_ID]) {
                NL_SET_ERR_MSG(extack, "Nexthop id is missing");
-               goto out;
+               return -EINVAL;
        }
 
        *id = nla_get_u32(tb[NHA_ID]);
-       if (!(*id))
+       if (!(*id)) {
                NL_SET_ERR_MSG(extack, "Invalid nexthop id");
-       else
-               err = 0;
-out:
-       return err;
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+static int nh_valid_get_del_req(const struct nlmsghdr *nlh, u32 *id,
+                               struct netlink_ext_ack *extack)
+{
+       struct nlattr *tb[ARRAY_SIZE(rtm_nh_policy_get)];
+       int err;
+
+       err = nlmsg_parse(nlh, sizeof(struct nhmsg), tb,
+                         ARRAY_SIZE(rtm_nh_policy_get) - 1,
+                         rtm_nh_policy_get, extack);
+       if (err < 0)
+               return err;
+
+       return __nh_valid_get_del_req(nlh, tb, id, extack);
 }
 
 /* rtnl */