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authorPetr Machata <petrm@mellanox.com>2020-06-27 01:45:26 +0300
committerDavid S. Miller <davem@davemloft.net>2020-06-29 17:08:28 -0700
commit3625750f05ecce21a0fce429c1ff85acfffb461b (patch)
tree70e057c139e1f1261377f3641f143b6b72f82868 /net
parentaebe4426ccaa4838f36ea805cdf7d76503e65117 (diff)
downloadlinux-3625750f05ecce21a0fce429c1ff85acfffb461b.tar.bz2
net: sched: Introduce helpers for qevent blocks
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() should be invoked when qdisc hits the "interesting event" corresponding to a block. This function releases root lock for the duration of executing the attached filters, to allow packets generated through user actions (notably mirred) to be reinserted to the same qdisc tree. Signed-off-by: Petr Machata <petrm@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/sched/cls_api.c119
1 files changed, 119 insertions, 0 deletions
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 5bfa6b985bb8..1b14d5f57e7f 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -3748,6 +3748,125 @@ unsigned int tcf_exts_num_actions(struct tcf_exts *exts)
}
EXPORT_SYMBOL(tcf_exts_num_actions);
+#ifdef CONFIG_NET_CLS_ACT
+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,
+ spinlock_t *root_lock, 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);
+
+ if (root_lock)
+ spin_unlock(root_lock);
+
+ 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;
+ }
+
+ if (root_lock)
+ spin_lock(root_lock);
+
+ return skb;
+}
+EXPORT_SYMBOL(tcf_qevent_handle);
+
+int tcf_qevent_dump(struct sk_buff *skb, int attr_name, struct tcf_qevent *qe)
+{
+ if (!qe->info.block_index)
+ return 0;
+ return nla_put_u32(skb, attr_name, qe->info.block_index);
+}
+EXPORT_SYMBOL(tcf_qevent_dump);
+#endif
+
static __net_init int tcf_net_init(struct net *net)
{
struct tcf_net *tn = net_generic(net, tcf_net_id);