net sched actions: calculate add/delete event message size

Introduce routines to calculate size of the shared tc netlink attributes
and the full message size including netlink header and tc service header.

Update add/delete action logic to have the size for event messages,
the size is passed to tcf_add_notify() and tcf_del_notify() where the
notification message is being allocated and constructed.

Signed-off-by: Roman Mashak <mrv@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index 3de0e06..57cf371 100644 (file)
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -109,6 +109,42 @@ int __tcf_idr_release(struct tc_action *p, bool bind, bool strict)
 }
 EXPORT_SYMBOL(__tcf_idr_release);
 
+static size_t tcf_action_shared_attrs_size(const struct tc_action *act)
+{
+       u32 cookie_len = 0;
+
+       if (act->act_cookie)
+               cookie_len = nla_total_size(act->act_cookie->len);
+
+       return  nla_total_size(0) /* action number nested */
+               + nla_total_size(IFNAMSIZ) /* TCA_ACT_KIND */
+               + cookie_len /* TCA_ACT_COOKIE */
+               + nla_total_size(0) /* TCA_ACT_STATS nested */
+               /* TCA_STATS_BASIC */
+               + nla_total_size_64bit(sizeof(struct gnet_stats_basic))
+               /* TCA_STATS_QUEUE */
+               + nla_total_size_64bit(sizeof(struct gnet_stats_queue))
+               + nla_total_size(0) /* TCA_OPTIONS nested */
+               + nla_total_size(sizeof(struct tcf_t)); /* TCA_GACT_TM */
+}
+
+static size_t tcf_action_full_attrs_size(size_t sz)
+{
+       return NLMSG_HDRLEN                     /* struct nlmsghdr */
+               + sizeof(struct tcamsg)
+               + nla_total_size(0)             /* TCA_ACT_TAB nested */
+               + sz;
+}
+
+static size_t tcf_action_fill_size(const struct tc_action *act)
+{
+       size_t sz = tcf_action_shared_attrs_size(act);
+
+       if (act->ops->get_fill_size)
+               return act->ops->get_fill_size(act) + sz;
+       return sz;
+}
+
 static int tcf_dump_walker(struct tcf_idrinfo *idrinfo, struct sk_buff *skb,
                           struct netlink_callback *cb)
 {
@@ -746,6 +782,7 @@ int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla,
 {
        struct nlattr *tb[TCA_ACT_MAX_PRIO + 1];
        struct tc_action *act;
+       size_t sz = 0;
        int err;
        int i;
 
@@ -761,11 +798,14 @@ int tcf_action_init(struct net *net, struct tcf_proto *tp, struct nlattr *nla,
                        goto err;
                }
                act->order = i;
+               sz += tcf_action_fill_size(act);
                if (ovr)
                        act->tcfa_refcnt++;
                list_add_tail(&act->list, actions);
        }
 
+       *attr_size = tcf_action_full_attrs_size(sz);
+
        /* Remove the temp refcnt which was necessary to protect against
         * destroying an existing action which was being replaced
         */
@@ -1056,9 +1096,12 @@ tca_action_gd(struct net *net, struct nlattr *nla, struct nlmsghdr *n,
                        goto err;
                }
                act->order = i;
+               attr_size += tcf_action_fill_size(act);
                list_add_tail(&act->list, &actions);
        }
 
+       attr_size = tcf_action_full_attrs_size(attr_size);
+
        if (event == RTM_GETACTION)
                ret = tcf_get_notify(net, portid, n, &actions, event, extack);
        else { /* delete */