Qevents are attach points for TC blocks, where filters can be put that are
executed when "interesting events" take place in a qdisc. The data to keep
and the functions to invoke to maintain a qevent will be largely the same
between qevents. Therefore introduce sched-wide helpers for qevent
management.
Currently, similarly to ingress and egress blocks of clsact pseudo-qdisc,
blocks attachment cannot be changed after the qdisc is created. To that
end, add a helper tcf_qevent_validate_change(), which verifies whether
block index attribute is not attached, or if it is, whether its value
matches the current one (i.e. there is no material change).
The function tcf_qevent_handle() is supposed to be invoked when qdisc hits
the "interesting event" corresponding to this block.
Signed-off-by: Petr Machata <pe...@mellanox.com>
---
include/net/pkt_cls.h | 48 +++++++++++++++++++
net/sched/cls_api.c | 107 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 155 insertions(+)
diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index ed65619cbc47..efb20e3c2c98 100644
--- a/include/net/pkt_cls.h
+++ b/include/net/pkt_cls.h
@@ -32,6 +32,13 @@ struct tcf_block_ext_info {
u32 block_index;
};
+struct tcf_qevent {
+ int attr_name;
+ struct tcf_block *block;
+ struct tcf_block_ext_info info;
+ struct tcf_proto __rcu *filter_chain;
+};
+
struct tcf_block_cb;
bool tcf_queue_work(struct rcu_work *rwork, work_func_t func);
@@ -552,6 +559,47 @@ int tc_setup_cb_reoffload(struct tcf_block *block, struct
tcf_proto *tp,
void *cb_priv, u32 *flags, unsigned int *in_hw_count);
unsigned int tcf_exts_num_actions(struct tcf_exts *exts);
+#ifdef CONFIG_NET_CLS_ACT
+int tcf_qevent_init(struct tcf_qevent *qe, struct Qdisc *sch,
+ enum flow_block_binder_type binder_type,
+ struct nlattr *block_index_attr,
+ struct netlink_ext_ack *extack);
+void tcf_qevent_destroy(struct tcf_qevent *qe, struct Qdisc *sch);
+int tcf_qevent_validate_change(struct tcf_qevent *qe,
+ struct nlattr *block_index_attr,
+ struct netlink_ext_ack *extack);
+struct sk_buff *tcf_qevent_handle(struct tcf_qevent *qe, struct Qdisc *sch,
+ struct sk_buff *skb, struct sk_buff **to_free,
+ int *ret);
+#else
+static inline int tcf_qevent_init(struct tcf_qevent *qe, struct Qdisc *sch,
+ enum flow_block_binder_type binder_type,
+ struct nlattr *block_index_attr,
+ struct netlink_ext_ack *extack)
+{
+ return 0;
+}
+
+static inline void tcf_qevent_destroy(struct tcf_qevent *qe, struct Qdisc *sch)
+{
+}
+
+static inline int tcf_qevent_validate_change(struct tcf_qevent *qe,
+ struct nlattr *block_index_attr,
+ struct netlink_ext_ack *extack)
+{
+ return 0;
+}
+
+static inline struct sk_buff *
+tcf_qevent_handle(struct tcf_qevent *qe, struct Qdisc *sch,
+ struct sk_buff *skb, struct sk_buff **to_free,
+ int *ret)
+{
+ return skb;
+}
+#endif
+
struct tc_cls_u32_knode {
struct tcf_exts *exts;
struct tcf_result *res;
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 752d608f4442..f95a5eee9279 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -3801,6 +3801,113 @@ unsigned int tcf_exts_num_actions(struct tcf_exts *exts)
}
EXPORT_SYMBOL(tcf_exts_num_actions);
+static int tcf_qevent_parse_block_index(struct nlattr *block_index_attr,
+ u32 *p_block_index,
+ struct netlink_ext_ack *extack)
+{
+ *p_block_index = nla_get_u32(block_index_attr);
+ if (!*p_block_index) {
+ NL_SET_ERR_MSG(extack, "Block number may not be zero");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+int tcf_qevent_init(struct tcf_qevent *qe, struct Qdisc *sch,
+ enum flow_block_binder_type binder_type,
+ struct nlattr *block_index_attr,
+ struct netlink_ext_ack *extack)
+{
+ u32 block_index;
+ int err;
+
+ if (!block_index_attr)
+ return 0;
+
+ err = tcf_qevent_parse_block_index(block_index_attr, &block_index,
+ extack);
+ if (err)
+ return err;
+
+ if (!block_index)
+ return 0;
+
+ qe->info.binder_type = binder_type;
+ qe->info.chain_head_change = tcf_chain_head_change_dflt;
+ qe->info.chain_head_change_priv = &qe->filter_chain;
+ qe->info.block_index = block_index;
+
+ return tcf_block_get_ext(&qe->block, sch, &qe->info, extack);
+}
+EXPORT_SYMBOL(tcf_qevent_init);
+
+void tcf_qevent_destroy(struct tcf_qevent *qe, struct Qdisc *sch)
+{
+ if (qe->info.block_index)
+ tcf_block_put_ext(qe->block, sch, &qe->info);
+}
+EXPORT_SYMBOL(tcf_qevent_destroy);
+
+int tcf_qevent_validate_change(struct tcf_qevent *qe,
+ struct nlattr *block_index_attr,
+ struct netlink_ext_ack *extack)
+{
+ u32 block_index;
+ int err;
+
+ if (!block_index_attr)
+ return 0;
+
+ err = tcf_qevent_parse_block_index(block_index_attr, &block_index,
+ extack);
+ if (err)
+ return err;
+
+ /* Bounce newly-configured block or change in block. */
+ if (block_index != qe->info.block_index) {
+ NL_SET_ERR_MSG(extack, "Change of blocks is not supported");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(tcf_qevent_validate_change);
+
+struct sk_buff *tcf_qevent_handle(struct tcf_qevent *qe, struct Qdisc *sch,
+ struct sk_buff *skb, struct sk_buff **to_free,
+ int *ret)
+{
+ struct tcf_result cl_res;
+ struct tcf_proto *fl;
+
+ if (!qe->info.block_index)
+ return skb;
+
+ fl = rcu_dereference_bh(qe->filter_chain);
+
+ switch (tcf_classify(skb, fl, &cl_res, false)) {
+ case TC_ACT_SHOT:
+ qdisc_qstats_drop(sch);
+ __qdisc_drop(skb, to_free);
+ *ret = __NET_XMIT_BYPASS;
+ return NULL;
+ case TC_ACT_STOLEN:
+ case TC_ACT_QUEUED:
+ case TC_ACT_TRAP:
+ __qdisc_drop(skb, to_free);
+ *ret = __NET_XMIT_STOLEN;
+ return NULL;
+ case TC_ACT_REDIRECT:
+ skb_do_redirect(skb);
+ *ret = __NET_XMIT_STOLEN;
+ return NULL;
+ }
+
+ return skb;
+}
+EXPORT_SYMBOL(tcf_qevent_handle);
+
static __net_init int tcf_net_init(struct net *net)
{
struct tcf_net *tn = net_generic(net, tcf_net_id);
--
2.20.1
