1 files changed, 534 insertions, 163 deletions

diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index b91ea03e3afa..bcb4ccb5f894 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -24,6 +24,7 @@
 #include <linux/init.h>
 #include <linux/kmod.h>
 #include <linux/slab.h>
+#include <linux/idr.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
 #include <net/netlink.h>
@@ -121,8 +122,8 @@ static inline u32 tcf_auto_prio(struct tcf_proto *tp)
 }
 
 static struct tcf_proto *tcf_proto_create(const char *kind, u32 protocol,
-					  u32 prio, u32 parent, struct Qdisc *q,
-					  struct tcf_chain *chain)
+					  u32 prio, struct tcf_chain *chain,
+					  struct netlink_ext_ack *extack)
 {
 	struct tcf_proto *tp;
 	int err;
@@ -148,6 +149,7 @@ static struct tcf_proto *tcf_proto_create(const char *kind, u32 protocol,
 			module_put(tp->ops->owner);
 			err = -EAGAIN;
 		} else {
+			NL_SET_ERR_MSG(extack, "TC classifier not found");
 			err = -ENOENT;
 		}
 		goto errout;
@@ -156,8 +158,6 @@ static struct tcf_proto *tcf_proto_create(const char *kind, u32 protocol,
 	tp->classify = tp->ops->classify;
 	tp->protocol = protocol;
 	tp->prio = prio;
-	tp->classid = parent;
-	tp->q = q;
 	tp->chain = chain;
 
 	err = tp->ops->init(tp);
@@ -172,13 +172,20 @@ errout:
 	return ERR_PTR(err);
 }
 
-static void tcf_proto_destroy(struct tcf_proto *tp)
+static void tcf_proto_destroy(struct tcf_proto *tp,
+			      struct netlink_ext_ack *extack)
 {
-	tp->ops->destroy(tp);
+	tp->ops->destroy(tp, extack);
 	module_put(tp->ops->owner);
 	kfree_rcu(tp, rcu);
 }
 
+struct tcf_filter_chain_list_item {
+	struct list_head list;
+	tcf_chain_head_change_t *chain_head_change;
+	void *chain_head_change_priv;
+};
+
 static struct tcf_chain *tcf_chain_create(struct tcf_block *block,
 					  u32 chain_index)
 {
@@ -187,6 +194,7 @@ static struct tcf_chain *tcf_chain_create(struct tcf_block *block,
 	chain = kzalloc(sizeof(*chain), GFP_KERNEL);
 	if (!chain)
 		return NULL;
+	INIT_LIST_HEAD(&chain->filter_chain_list);
 	list_add_tail(&chain->list, &block->chain_list);
 	chain->block = block;
 	chain->index = chain_index;
@@ -194,12 +202,19 @@ static struct tcf_chain *tcf_chain_create(struct tcf_block *block,
 	return chain;
 }
 
+static void tcf_chain_head_change_item(struct tcf_filter_chain_list_item *item,
+				       struct tcf_proto *tp_head)
+{
+	if (item->chain_head_change)
+		item->chain_head_change(tp_head, item->chain_head_change_priv);
+}
 static void tcf_chain_head_change(struct tcf_chain *chain,
 				  struct tcf_proto *tp_head)
 {
-	if (chain->chain_head_change)
-		chain->chain_head_change(tp_head,
-					 chain->chain_head_change_priv);
+	struct tcf_filter_chain_list_item *item;
+
+	list_for_each_entry(item, &chain->filter_chain_list, list)
+		tcf_chain_head_change_item(item, tp_head);
 }
 
 static void tcf_chain_flush(struct tcf_chain *chain)
@@ -209,7 +224,7 @@ static void tcf_chain_flush(struct tcf_chain *chain)
 	tcf_chain_head_change(chain, NULL);
 	while (tp) {
 		RCU_INIT_POINTER(chain->filter_chain, tp->next);
-		tcf_proto_destroy(tp);
+		tcf_proto_destroy(tp, NULL);
 		tp = rtnl_dereference(chain->filter_chain);
 		tcf_chain_put(chain);
 	}
@@ -217,8 +232,12 @@ static void tcf_chain_flush(struct tcf_chain *chain)
 
 static void tcf_chain_destroy(struct tcf_chain *chain)
 {
+	struct tcf_block *block = chain->block;
+
 	list_del(&chain->list);
 	kfree(chain);
+	if (list_empty(&block->chain_list))
+		kfree(block);
 }
 
 static void tcf_chain_hold(struct tcf_chain *chain)
@@ -249,62 +268,300 @@ void tcf_chain_put(struct tcf_chain *chain)
 }
 EXPORT_SYMBOL(tcf_chain_put);
 
-static void tcf_block_offload_cmd(struct tcf_block *block, struct Qdisc *q,
-				  struct tcf_block_ext_info *ei,
-				  enum tc_block_command command)
+static bool tcf_block_offload_in_use(struct tcf_block *block)
+{
+	return block->offloadcnt;
+}
+
+static int tcf_block_offload_cmd(struct tcf_block *block,
+				 struct net_device *dev,
+				 struct tcf_block_ext_info *ei,
+				 enum tc_block_command command)
 {
-	struct net_device *dev = q->dev_queue->dev;
 	struct tc_block_offload bo = {};
 
-	if (!dev->netdev_ops->ndo_setup_tc)
-		return;
 	bo.command = command;
 	bo.binder_type = ei->binder_type;
 	bo.block = block;
-	dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_BLOCK, &bo);
+	return dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_BLOCK, &bo);
 }
 
-static void tcf_block_offload_bind(struct tcf_block *block, struct Qdisc *q,
-				   struct tcf_block_ext_info *ei)
+static int tcf_block_offload_bind(struct tcf_block *block, struct Qdisc *q,
+				  struct tcf_block_ext_info *ei)
 {
-	tcf_block_offload_cmd(block, q, ei, TC_BLOCK_BIND);
+	struct net_device *dev = q->dev_queue->dev;
+	int err;
+
+	if (!dev->netdev_ops->ndo_setup_tc)
+		goto no_offload_dev_inc;
+
+	/* If tc offload feature is disabled and the block we try to bind
+	 * to already has some offloaded filters, forbid to bind.
+	 */
+	if (!tc_can_offload(dev) && tcf_block_offload_in_use(block))
+		return -EOPNOTSUPP;
+
+	err = tcf_block_offload_cmd(block, dev, ei, TC_BLOCK_BIND);
+	if (err == -EOPNOTSUPP)
+		goto no_offload_dev_inc;
+	return err;
+
+no_offload_dev_inc:
+	if (tcf_block_offload_in_use(block))
+		return -EOPNOTSUPP;
+	block->nooffloaddevcnt++;
+	return 0;
 }
 
 static void tcf_block_offload_unbind(struct tcf_block *block, struct Qdisc *q,
 				     struct tcf_block_ext_info *ei)
 {
-	tcf_block_offload_cmd(block, q, ei, TC_BLOCK_UNBIND);
+	struct net_device *dev = q->dev_queue->dev;
+	int err;
+
+	if (!dev->netdev_ops->ndo_setup_tc)
+		goto no_offload_dev_dec;
+	err = tcf_block_offload_cmd(block, dev, ei, TC_BLOCK_UNBIND);
+	if (err == -EOPNOTSUPP)
+		goto no_offload_dev_dec;
+	return;
+
+no_offload_dev_dec:
+	WARN_ON(block->nooffloaddevcnt-- == 0);
+}
+
+static int
+tcf_chain_head_change_cb_add(struct tcf_chain *chain,
+			     struct tcf_block_ext_info *ei,
+			     struct netlink_ext_ack *extack)
+{
+	struct tcf_filter_chain_list_item *item;
+
+	item = kmalloc(sizeof(*item), GFP_KERNEL);
+	if (!item) {
+		NL_SET_ERR_MSG(extack, "Memory allocation for head change callback item failed");
+		return -ENOMEM;
+	}
+	item->chain_head_change = ei->chain_head_change;
+	item->chain_head_change_priv = ei->chain_head_change_priv;
+	if (chain->filter_chain)
+		tcf_chain_head_change_item(item, chain->filter_chain);
+	list_add(&item->list, &chain->filter_chain_list);
+	return 0;
+}
+
+static void
+tcf_chain_head_change_cb_del(struct tcf_chain *chain,
+			     struct tcf_block_ext_info *ei)
+{
+	struct tcf_filter_chain_list_item *item;
+
+	list_for_each_entry(item, &chain->filter_chain_list, list) {
+		if ((!ei->chain_head_change && !ei->chain_head_change_priv) ||
+		    (item->chain_head_change == ei->chain_head_change &&
+		     item->chain_head_change_priv == ei->chain_head_change_priv)) {
+			tcf_chain_head_change_item(item, NULL);
+			list_del(&item->list);
+			kfree(item);
+			return;
+		}
+	}
+	WARN_ON(1);
 }
 
-int tcf_block_get_ext(struct tcf_block **p_block, struct Qdisc *q,
-		      struct tcf_block_ext_info *ei)
+struct tcf_net {
+	struct idr idr;
+};
+
+static unsigned int tcf_net_id;
+
+static int tcf_block_insert(struct tcf_block *block, struct net *net,
+			    u32 block_index, struct netlink_ext_ack *extack)
+{
+	struct tcf_net *tn = net_generic(net, tcf_net_id);
+	int err;
+
+	err = idr_alloc_ext(&tn->idr, block, NULL, block_index,
+			    block_index + 1, GFP_KERNEL);
+	if (err)
+		return err;
+	block->index = block_index;
+	return 0;
+}
+
+static void tcf_block_remove(struct tcf_block *block, struct net *net)
 {
-	struct tcf_block *block = kzalloc(sizeof(*block), GFP_KERNEL);
+	struct tcf_net *tn = net_generic(net, tcf_net_id);
+
+	idr_remove_ext(&tn->idr, block->index);
+}
+
+static struct tcf_block *tcf_block_create(struct net *net, struct Qdisc *q,
+					  struct netlink_ext_ack *extack)
+{
+	struct tcf_block *block;
 	struct tcf_chain *chain;
 	int err;
 
-	if (!block)
-		return -ENOMEM;
+	block = kzalloc(sizeof(*block), GFP_KERNEL);
+	if (!block) {
+		NL_SET_ERR_MSG(extack, "Memory allocation for block failed");
+		return ERR_PTR(-ENOMEM);
+	}
 	INIT_LIST_HEAD(&block->chain_list);
 	INIT_LIST_HEAD(&block->cb_list);
+	INIT_LIST_HEAD(&block->owner_list);
 
 	/* Create chain 0 by default, it has to be always present. */
 	chain = tcf_chain_create(block, 0);
 	if (!chain) {
+		NL_SET_ERR_MSG(extack, "Failed to create new tcf chain");
 		err = -ENOMEM;
 		goto err_chain_create;
 	}
-	WARN_ON(!ei->chain_head_change);
-	chain->chain_head_change = ei->chain_head_change;
-	chain->chain_head_change_priv = ei->chain_head_change_priv;
 	block->net = qdisc_net(q);
+	block->refcnt = 1;
+	block->net = net;
 	block->q = q;
-	tcf_block_offload_bind(block, q, ei);
-	*p_block = block;
-	return 0;
+	return block;
 
 err_chain_create:
 	kfree(block);
+	return ERR_PTR(err);
+}
+
+static struct tcf_block *tcf_block_lookup(struct net *net, u32 block_index)
+{
+	struct tcf_net *tn = net_generic(net, tcf_net_id);
+
+	return idr_find_ext(&tn->idr, block_index);
+}
+
+static struct tcf_chain *tcf_block_chain_zero(struct tcf_block *block)
+{
+	return list_first_entry(&block->chain_list, struct tcf_chain, list);
+}
+
+struct tcf_block_owner_item {
+	struct list_head list;
+	struct Qdisc *q;
+	enum tcf_block_binder_type binder_type;
+};
+
+static void
+tcf_block_owner_netif_keep_dst(struct tcf_block *block,
+			       struct Qdisc *q,
+			       enum tcf_block_binder_type binder_type)
+{
+	if (block->keep_dst &&
+	    binder_type != TCF_BLOCK_BINDER_TYPE_CLSACT_INGRESS &&
+	    binder_type != TCF_BLOCK_BINDER_TYPE_CLSACT_EGRESS)
+		netif_keep_dst(qdisc_dev(q));
+}
+
+void tcf_block_netif_keep_dst(struct tcf_block *block)
+{
+	struct tcf_block_owner_item *item;
+
+	block->keep_dst = true;
+	list_for_each_entry(item, &block->owner_list, list)
+		tcf_block_owner_netif_keep_dst(block, item->q,
+					       item->binder_type);
+}
+EXPORT_SYMBOL(tcf_block_netif_keep_dst);
+
+static int tcf_block_owner_add(struct tcf_block *block,
+			       struct Qdisc *q,
+			       enum tcf_block_binder_type binder_type)
+{
+	struct tcf_block_owner_item *item;
+
+	item = kmalloc(sizeof(*item), GFP_KERNEL);
+	if (!item)
+		return -ENOMEM;
+	item->q = q;
+	item->binder_type = binder_type;
+	list_add(&item->list, &block->owner_list);
+	return 0;
+}
+
+static void tcf_block_owner_del(struct tcf_block *block,
+				struct Qdisc *q,
+				enum tcf_block_binder_type binder_type)
+{
+	struct tcf_block_owner_item *item;
+
+	list_for_each_entry(item, &block->owner_list, list) {
+		if (item->q == q && item->binder_type == binder_type) {
+			list_del(&item->list);
+			kfree(item);
+			return;
+		}
+	}
+	WARN_ON(1);
+}
+
+int tcf_block_get_ext(struct tcf_block **p_block, struct Qdisc *q,
+		      struct tcf_block_ext_info *ei,
+		      struct netlink_ext_ack *extack)
+{
+	struct net *net = qdisc_net(q);
+	struct tcf_block *block = NULL;
+	bool created = false;
+	int err;
+
+	if (ei->block_index) {
+		/* block_index not 0 means the shared block is requested */
+		block = tcf_block_lookup(net, ei->block_index);
+		if (block)
+			block->refcnt++;
+	}
+
+	if (!block) {
+		block = tcf_block_create(net, q, extack);
+		if (IS_ERR(block))
+			return PTR_ERR(block);
+		created = true;
+		if (ei->block_index) {
+			err = tcf_block_insert(block, net,
+					       ei->block_index, extack);
+			if (err)
+				goto err_block_insert;
+		}
+	}
+
+	err = tcf_block_owner_add(block, q, ei->binder_type);
+	if (err)
+		goto err_block_owner_add;
+
+	tcf_block_owner_netif_keep_dst(block, q, ei->binder_type);
+
+	err = tcf_chain_head_change_cb_add(tcf_block_chain_zero(block),
+					   ei, extack);
+	if (err)
+		goto err_chain_head_change_cb_add;
+
+	err = tcf_block_offload_bind(block, q, ei);
+	if (err)
+		goto err_block_offload_bind;
+
+	*p_block = block;
+	return 0;
+
+err_block_offload_bind:
+	tcf_chain_head_change_cb_del(tcf_block_chain_zero(block), ei);
+err_chain_head_change_cb_add:
+	tcf_block_owner_del(block, q, ei->binder_type);
+err_block_owner_add:
+	if (created) {
+		if (tcf_block_shared(block))
+			tcf_block_remove(block, net);
+err_block_insert:
+		kfree(tcf_block_chain_zero(block));
+		kfree(block);
+	} else {
+		block->refcnt--;
+	}
 	return err;
 }
 EXPORT_SYMBOL(tcf_block_get_ext);
@@ -317,7 +574,8 @@ static void tcf_chain_head_change_dflt(struct tcf_proto *tp_head, void *priv)
 }
 
 int tcf_block_get(struct tcf_block **p_block,
-		  struct tcf_proto __rcu **p_filter_chain, struct Qdisc *q)
+		  struct tcf_proto __rcu **p_filter_chain, struct Qdisc *q,
+		  struct netlink_ext_ack *extack)
 {
 	struct tcf_block_ext_info ei = {
 		.chain_head_change = tcf_chain_head_change_dflt,
@@ -325,53 +583,47 @@ int tcf_block_get(struct tcf_block **p_block,
 	};
 
 	WARN_ON(!p_filter_chain);
-	return tcf_block_get_ext(p_block, q, &ei);
+	return tcf_block_get_ext(p_block, q, &ei, extack);
 }
 EXPORT_SYMBOL(tcf_block_get);
 
-static void tcf_block_put_final(struct work_struct *work)
-{
-	struct tcf_block *block = container_of(work, struct tcf_block, work);
-	struct tcf_chain *chain, *tmp;
-
-	rtnl_lock();
-
-	/* At this point, all the chains should have refcnt == 1. */
-	list_for_each_entry_safe(chain, tmp, &block->chain_list, list)
-		tcf_chain_put(chain);
-	rtnl_unlock();
-	kfree(block);
-}
-
 /* XXX: Standalone actions are not allowed to jump to any chain, and bound
  * actions should be all removed after flushing.
  */
 void tcf_block_put_ext(struct tcf_block *block, struct Qdisc *q,
 		       struct tcf_block_ext_info *ei)
 {
-	struct tcf_chain *chain;
+	struct tcf_chain *chain, *tmp;
 
 	if (!block)
 		return;
-	/* Hold a refcnt for all chains, except 0, so that they don't disappear
-	 * while we are iterating.
-	 */
-	list_for_each_entry(chain, &block->chain_list, list)
-		if (chain->index)
+	tcf_chain_head_change_cb_del(tcf_block_chain_zero(block), ei);
+	tcf_block_owner_del(block, q, ei->binder_type);
+
+	if (--block->refcnt == 0) {
+		if (tcf_block_shared(block))
+			tcf_block_remove(block, block->net);
+
+		/* Hold a refcnt for all chains, so that they don't disappear
+		 * while we are iterating.
+		 */
+		list_for_each_entry(chain, &block->chain_list, list)
 			tcf_chain_hold(chain);
 
-	list_for_each_entry(chain, &block->chain_list, list)
-		tcf_chain_flush(chain);
+		list_for_each_entry(chain, &block->chain_list, list)
+			tcf_chain_flush(chain);
+	}
 
 	tcf_block_offload_unbind(block, q, ei);
 
-	INIT_WORK(&block->work, tcf_block_put_final);
-	/* Wait for existing RCU callbacks to cool down, make sure their works
-	 * have been queued before this. We can not flush pending works here
-	 * because we are holding the RTNL lock.
-	 */
-	rcu_barrier();
-	tcf_queue_work(&block->work);
+	if (block->refcnt == 0) {
+		/* At this point, all the chains should have refcnt >= 1. */
+		list_for_each_entry_safe(chain, tmp, &block->chain_list, list)
+			tcf_chain_put(chain);
+
+		/* Finally, put chain 0 and allow block to be freed. */
+		tcf_chain_put(tcf_block_chain_zero(block));
+	}
 }
 EXPORT_SYMBOL(tcf_block_put_ext);
 
@@ -379,6 +631,8 @@ void tcf_block_put(struct tcf_block *block)
 {
 	struct tcf_block_ext_info ei = {0, };
 
+	if (!block)
+		return;
 	tcf_block_put_ext(block, block->q, &ei);
 }
 
@@ -427,9 +681,16 @@ struct tcf_block_cb *__tcf_block_cb_register(struct tcf_block *block,
 {
 	struct tcf_block_cb *block_cb;
 
+	/* At this point, playback of previous block cb calls is not supported,
+	 * so forbid to register to block which already has some offloaded
+	 * filters present.
+	 */
+	if (tcf_block_offload_in_use(block))
+		return ERR_PTR(-EOPNOTSUPP);
+
 	block_cb = kzalloc(sizeof(*block_cb), GFP_KERNEL);
 	if (!block_cb)
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 	block_cb->cb = cb;
 	block_cb->cb_ident = cb_ident;
 	block_cb->cb_priv = cb_priv;
@@ -445,7 +706,7 @@ int tcf_block_cb_register(struct tcf_block *block,
 	struct tcf_block_cb *block_cb;
 
 	block_cb = __tcf_block_cb_register(block, cb, cb_ident, cb_priv);
-	return block_cb ? 0 : -ENOMEM;
+	return IS_ERR(block_cb) ? PTR_ERR(block_cb) : 0;
 }
 EXPORT_SYMBOL(tcf_block_cb_register);
 
@@ -475,6 +736,10 @@ static int tcf_block_cb_call(struct tcf_block *block, enum tc_setup_type type,
 	int ok_count = 0;
 	int err;
 
+	/* Make sure all netdevs sharing this block are offload-capable. */
+	if (block->nooffloaddevcnt && err_stop)
+		return -EOPNOTSUPP;
+
 	list_for_each_entry(block_cb, &block->cb_list, list) {
 		err = block_cb->cb(type, type_data, block_cb->cb_priv);
 		if (err) {
@@ -528,8 +793,9 @@ reclassify:
 #ifdef CONFIG_NET_CLS_ACT
 reset:
 	if (unlikely(limit++ >= max_reclassify_loop)) {
-		net_notice_ratelimited("%s: reclassify loop, rule prio %u, protocol %02x\n",
-				       tp->q->ops->id, tp->prio & 0xffff,
+		net_notice_ratelimited("%u: reclassify loop, rule prio %u, protocol %02x\n",
+				       tp->chain->block->index,
+				       tp->prio & 0xffff,
 				       ntohs(tp->protocol));
 		return TC_ACT_SHOT;
 	}
@@ -602,8 +868,9 @@ static struct tcf_proto *tcf_chain_tp_find(struct tcf_chain *chain,
 }
 
 static int tcf_fill_node(struct net *net, struct sk_buff *skb,
-			 struct tcf_proto *tp, struct Qdisc *q, u32 parent,
-			 void *fh, u32 portid, u32 seq, u16 flags, int event)
+			 struct tcf_proto *tp, struct tcf_block *block,
+			 struct Qdisc *q, u32 parent, void *fh,
+			 u32 portid, u32 seq, u16 flags, int event)
 {
 	struct tcmsg *tcm;
 	struct nlmsghdr  *nlh;
@@ -616,8 +883,13 @@ static int tcf_fill_node(struct net *net, struct sk_buff *skb,
 	tcm->tcm_family = AF_UNSPEC;
 	tcm->tcm__pad1 = 0;
 	tcm->tcm__pad2 = 0;
-	tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
-	tcm->tcm_parent = parent;
+	if (q) {
+		tcm->tcm_ifindex = qdisc_dev(q)->ifindex;
+		tcm->tcm_parent = parent;
+	} else {
+		tcm->tcm_ifindex = TCM_IFINDEX_MAGIC_BLOCK;
+		tcm->tcm_block_index = block->index;
+	}
 	tcm->tcm_info = TC_H_MAKE(tp->prio, tp->protocol);
 	if (nla_put_string(skb, TCA_KIND, tp->ops->kind))
 		goto nla_put_failure;
@@ -640,8 +912,8 @@ nla_put_failure:
 
 static int tfilter_notify(struct net *net, struct sk_buff *oskb,
 			  struct nlmsghdr *n, struct tcf_proto *tp,
-			  struct Qdisc *q, u32 parent,
-			  void *fh, int event, bool unicast)
+			  struct tcf_block *block, struct Qdisc *q,
+			  u32 parent, void *fh, int event, bool unicast)
 {
 	struct sk_buff *skb;
 	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
@@ -650,8 +922,8 @@ static int tfilter_notify(struct net *net, struct sk_buff *oskb,
 	if (!skb)
 		return -ENOBUFS;
 
-	if (tcf_fill_node(net, skb, tp, q, parent, fh, portid, n->nlmsg_seq,
-			  n->nlmsg_flags, event) <= 0) {
+	if (tcf_fill_node(net, skb, tp, block, q, parent, fh, portid,
+			  n->nlmsg_seq, n->nlmsg_flags, event) <= 0) {
 		kfree_skb(skb);
 		return -EINVAL;
 	}
@@ -665,8 +937,9 @@ static int tfilter_notify(struct net *net, struct sk_buff *oskb,
 
 static int tfilter_del_notify(struct net *net, struct sk_buff *oskb,
 			      struct nlmsghdr *n, struct tcf_proto *tp,
-			      struct Qdisc *q, u32 parent,
-			      void *fh, bool unicast, bool *last)
+			      struct tcf_block *block, struct Qdisc *q,
+			      u32 parent, void *fh, bool unicast, bool *last,
+			      struct netlink_ext_ack *extack)
 {
 	struct sk_buff *skb;
 	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
@@ -676,13 +949,14 @@ static int tfilter_del_notify(struct net *net, struct sk_buff *oskb,
 	if (!skb)
 		return -ENOBUFS;
 
-	if (tcf_fill_node(net, skb, tp, q, parent, fh, portid, n->nlmsg_seq,
-			  n->nlmsg_flags, RTM_DELTFILTER) <= 0) {
+	if (tcf_fill_node(net, skb, tp, block, q, parent, fh, portid,
+			  n->nlmsg_seq, n->nlmsg_flags, RTM_DELTFILTER) <= 0) {
+		NL_SET_ERR_MSG(extack, "Failed to build del event notification");
 		kfree_skb(skb);
 		return -EINVAL;
 	}
 
-	err = tp->ops->delete(tp, fh, last);
+	err = tp->ops->delete(tp, fh, last, extack);
 	if (err) {
 		kfree_skb(skb);
 		return err;
@@ -691,20 +965,24 @@ static int tfilter_del_notify(struct net *net, struct sk_buff *oskb,
 	if (unicast)
 		return netlink_unicast(net->rtnl, skb, portid, MSG_DONTWAIT);
 
-	return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
-			      n->nlmsg_flags & NLM_F_ECHO);
+	err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
+			     n->nlmsg_flags & NLM_F_ECHO);
+	if (err < 0)
+		NL_SET_ERR_MSG(extack, "Failed to send filter delete notification");
+	return err;
 }
 
 static void tfilter_notify_chain(struct net *net, struct sk_buff *oskb,
-				 struct Qdisc *q, u32 parent,
-				 struct nlmsghdr *n,
+				 struct tcf_block *block, struct Qdisc *q,
+				 u32 parent, struct nlmsghdr *n,
 				 struct tcf_chain *chain, int event)
 {
 	struct tcf_proto *tp;
 
 	for (tp = rtnl_dereference(chain->filter_chain);
 	     tp; tp = rtnl_dereference(tp->next))
-		tfilter_notify(net, oskb, n, tp, q, parent, 0, event, false);
+		tfilter_notify(net, oskb, n, tp, block,
+			       q, parent, 0, event, false);
 }
 
 /* Add/change/delete/get a filter node */
@@ -720,13 +998,11 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
 	bool prio_allocate;
 	u32 parent;
 	u32 chain_index;
-	struct net_device *dev;
-	struct Qdisc  *q;
+	struct Qdisc *q = NULL;
 	struct tcf_chain_info chain_info;
 	struct tcf_chain *chain = NULL;
 	struct tcf_block *block;
 	struct tcf_proto *tp;
-	const struct Qdisc_class_ops *cops;
 	unsigned long cl;
 	void *fh;
 	int err;
@@ -753,8 +1029,10 @@ replay:
 	if (prio == 0) {
 		switch (n->nlmsg_type) {
 		case RTM_DELTFILTER:
-			if (protocol || t->tcm_handle || tca[TCA_KIND])
+			if (protocol || t->tcm_handle || tca[TCA_KIND]) {
+				NL_SET_ERR_MSG(extack, "Cannot flush filters with protocol, handle or kind set");
 				return -ENOENT;
+			}
 			break;
 		case RTM_NEWTFILTER:
 			/* If no priority is provided by the user,
@@ -767,63 +1045,91 @@ replay:
 			}
 			/* fall-through */
 		default:
+			NL_SET_ERR_MSG(extack, "Invalid filter command with priority of zero");
 			return -ENOENT;
 		}
 	}
 
 	/* Find head of filter chain. */
 
-	/* Find link */
-	dev = __dev_get_by_index(net, t->tcm_ifindex);
-	if (dev == NULL)
-		return -ENODEV;
-
-	/* Find qdisc */
-	if (!parent) {
-		q = dev->qdisc;
-		parent = q->handle;
+	if (t->tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK) {
+		block = tcf_block_lookup(net, t->tcm_block_index);
+		if (!block) {
+			NL_SET_ERR_MSG(extack, "Block of given index was not found");
+			err = -EINVAL;
+			goto errout;
+		}
 	} else {
-		q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
-		if (q == NULL)
-			return -EINVAL;
-	}
+		const struct Qdisc_class_ops *cops;
+		struct net_device *dev;
 
-	/* Is it classful? */
-	cops = q->ops->cl_ops;
-	if (!cops)
-		return -EINVAL;
+		/* Find link */
+		dev = __dev_get_by_index(net, t->tcm_ifindex);
+		if (!dev)
+			return -ENODEV;
 
-	if (!cops->tcf_block)
-		return -EOPNOTSUPP;
+		/* Find qdisc */
+		if (!parent) {
+			q = dev->qdisc;
+			parent = q->handle;
+		} else {
+			q = qdisc_lookup(dev, TC_H_MAJ(t->tcm_parent));
+			if (!q) {
+				NL_SET_ERR_MSG(extack, "Parent Qdisc doesn't exists");
+				return -EINVAL;
+			}
+		}
 
-	/* Do we search for filter, attached to class? */
-	if (TC_H_MIN(parent)) {
-		cl = cops->find(q, parent);
-		if (cl == 0)
-			return -ENOENT;
-	}
+		/* Is it classful? */
+		cops = q->ops->cl_ops;
+		if (!cops) {
+			NL_SET_ERR_MSG(extack, "Qdisc not classful");
+			return -EINVAL;
+		}
 
-	/* And the last stroke */
-	block = cops->tcf_block(q, cl);
-	if (!block) {
-		err = -EINVAL;
-		goto errout;
+		if (!cops->tcf_block) {
+			NL_SET_ERR_MSG(extack, "Class doesn't support blocks");
+			return -EOPNOTSUPP;
+		}
+
+		/* Do we search for filter, attached to class? */
+		if (TC_H_MIN(parent)) {
+			cl = cops->find(q, parent);
+			if (cl == 0) {
+				NL_SET_ERR_MSG(extack, "Specified class doesn't exist");
+				return -ENOENT;
+			}
+		}
+
+		/* And the last stroke */
+		block = cops->tcf_block(q, cl, extack);
+		if (!block) {
+			err = -EINVAL;
+			goto errout;
+		}
+		if (tcf_block_shared(block)) {
+			NL_SET_ERR_MSG(extack, "This filter block is shared. Please use the block index to manipulate the filters");
+			err = -EOPNOTSUPP;
+			goto errout;
+		}
 	}
 
 	chain_index = tca[TCA_CHAIN] ? nla_get_u32(tca[TCA_CHAIN]) : 0;
 	if (chain_index > TC_ACT_EXT_VAL_MASK) {
+		NL_SET_ERR_MSG(extack, "Specified chain index exceeds upper limit");
 		err = -EINVAL;
 		goto errout;
 	}
 	chain = tcf_chain_get(block, chain_index,
 			      n->nlmsg_type == RTM_NEWTFILTER);
 	if (!chain) {
+		NL_SET_ERR_MSG(extack, "Cannot find specified filter chain");
 		err = n->nlmsg_type == RTM_NEWTFILTER ? -ENOMEM : -EINVAL;
 		goto errout;
 	}
 
 	if (n->nlmsg_type == RTM_DELTFILTER && prio == 0) {
-		tfilter_notify_chain(net, skb, q, parent, n,
+		tfilter_notify_chain(net, skb, block, q, parent, n,
 				     chain, RTM_DELTFILTER);
 		tcf_chain_flush(chain);
 		err = 0;
@@ -833,6 +1139,7 @@ replay:
 	tp = tcf_chain_tp_find(chain, &chain_info, protocol,
 			       prio, prio_allocate);
 	if (IS_ERR(tp)) {
+		NL_SET_ERR_MSG(extack, "Filter with specified priority/protocol not found");
 		err = PTR_ERR(tp);
 		goto errout;
 	}
@@ -841,12 +1148,14 @@ replay:
 		/* Proto-tcf does not exist, create new one */
 
 		if (tca[TCA_KIND] == NULL || !protocol) {
+			NL_SET_ERR_MSG(extack, "Filter kind and protocol must be specified");
 			err = -EINVAL;
 			goto errout;
 		}
 
 		if (n->nlmsg_type != RTM_NEWTFILTER ||
 		    !(n->nlmsg_flags & NLM_F_CREATE)) {
+			NL_SET_ERR_MSG(extack, "Need both RTM_NEWTFILTER and NLM_F_CREATE to create a new filter");
 			err = -ENOENT;
 			goto errout;
 		}
@@ -855,13 +1164,14 @@ replay:
 			prio = tcf_auto_prio(tcf_chain_tp_prev(&chain_info));
 
 		tp = tcf_proto_create(nla_data(tca[TCA_KIND]),
-				      protocol, prio, parent, q, chain);
+				      protocol, prio, chain, extack);
 		if (IS_ERR(tp)) {
 			err = PTR_ERR(tp);
 			goto errout;
 		}
 		tp_created = 1;
 	} else if (tca[TCA_KIND] && nla_strcmp(tca[TCA_KIND], tp->ops->kind)) {
+		NL_SET_ERR_MSG(extack, "Specified filter kind does not match existing one");
 		err = -EINVAL;
 		goto errout;
 	}
@@ -871,15 +1181,16 @@ replay:
 	if (!fh) {
 		if (n->nlmsg_type == RTM_DELTFILTER && t->tcm_handle == 0) {
 			tcf_chain_tp_remove(chain, &chain_info, tp);
-			tfilter_notify(net, skb, n, tp, q, parent, fh,
+			tfilter_notify(net, skb, n, tp, block, q, parent, fh,
 				       RTM_DELTFILTER, false);
-			tcf_proto_destroy(tp);
+			tcf_proto_destroy(tp, extack);
 			err = 0;
 			goto errout;
 		}
 
 		if (n->nlmsg_type != RTM_NEWTFILTER ||
 		    !(n->nlmsg_flags & NLM_F_CREATE)) {
+			NL_SET_ERR_MSG(extack, "Need both RTM_NEWTFILTER and NLM_F_CREATE to create a new filter");
 			err = -ENOENT;
 			goto errout;
 		}
@@ -890,41 +1201,47 @@ replay:
 		case RTM_NEWTFILTER:
 			if (n->nlmsg_flags & NLM_F_EXCL) {
 				if (tp_created)
-					tcf_proto_destroy(tp);
+					tcf_proto_destroy(tp, NULL);
+				NL_SET_ERR_MSG(extack, "Filter already exists");
 				err = -EEXIST;
 				goto errout;
 			}
 			break;
 		case RTM_DELTFILTER:
-			err = tfilter_del_notify(net, skb, n, tp, q, parent,
-						 fh, false, &last);
+			err = tfilter_del_notify(net, skb, n, tp, block,
+						 q, parent, fh, false, &last,
+						 extack);
 			if (err)
 				goto errout;
 			if (last) {
 				tcf_chain_tp_remove(chain, &chain_info, tp);
-				tcf_proto_destroy(tp);
+				tcf_proto_destroy(tp, extack);
 			}
 			goto errout;
 		case RTM_GETTFILTER:
-			err = tfilter_notify(net, skb, n, tp, q, parent, fh,
-					     RTM_NEWTFILTER, true);
+			err = tfilter_notify(net, skb, n, tp, block, q, parent,
+					     fh, RTM_NEWTFILTER, true);
+			if (err < 0)
+				NL_SET_ERR_MSG(extack, "Failed to send filter notify message");
 			goto errout;
 		default:
+			NL_SET_ERR_MSG(extack, "Invalid netlink message type");
 			err = -EINVAL;
 			goto errout;
 		}
 	}
 
 	err = tp->ops->change(net, skb, tp, cl, t->tcm_handle, tca, &fh,
-			      n->nlmsg_flags & NLM_F_CREATE ? TCA_ACT_NOREPLACE : TCA_ACT_REPLACE);
+			      n->nlmsg_flags & NLM_F_CREATE ? TCA_ACT_NOREPLACE : TCA_ACT_REPLACE,
+			      extack);
 	if (err == 0) {
 		if (tp_created)
 			tcf_chain_tp_insert(chain, &chain_info, tp);
-		tfilter_notify(net, skb, n, tp, q, parent, fh,
+		tfilter_notify(net, skb, n, tp, block, q, parent, fh,
 			       RTM_NEWTFILTER, false);
 	} else {
 		if (tp_created)
-			tcf_proto_destroy(tp);
+			tcf_proto_destroy(tp, NULL);
 	}
 
 errout:
@@ -940,6 +1257,7 @@ struct tcf_dump_args {
 	struct tcf_walker w;
 	struct sk_buff *skb;
 	struct netlink_callback *cb;
+	struct tcf_block *block;
 	struct Qdisc *q;
 	u32 parent;
 };
@@ -949,7 +1267,7 @@ static int tcf_node_dump(struct tcf_proto *tp, void *n, struct tcf_walker *arg)
 	struct tcf_dump_args *a = (void *)arg;
 	struct net *net = sock_net(a->skb->sk);
 
-	return tcf_fill_node(net, a->skb, tp, a->q, a->parent,
+	return tcf_fill_node(net, a->skb, tp, a->block, a->q, a->parent,
 			     n, NETLINK_CB(a->cb->skb).portid,
 			     a->cb->nlh->nlmsg_seq, NLM_F_MULTI,
 			     RTM_NEWTFILTER);
@@ -960,6 +1278,7 @@ static bool tcf_chain_dump(struct tcf_chain *chain, struct Qdisc *q, u32 parent,
 			   long index_start, long *p_index)
 {
 	struct net *net = sock_net(skb->sk);
+	struct tcf_block *block = chain->block;
 	struct tcmsg *tcm = nlmsg_data(cb->nlh);
 	struct tcf_dump_args arg;
 	struct tcf_proto *tp;
@@ -978,7 +1297,7 @@ static bool tcf_chain_dump(struct tcf_chain *chain, struct Qdisc *q, u32 parent,
 			memset(&cb->args[1], 0,
 			       sizeof(cb->args) - sizeof(cb->args[0]));
 		if (cb->args[1] == 0) {
-			if (tcf_fill_node(net, skb, tp, q, parent, 0,
+			if (tcf_fill_node(net, skb, tp, block, q, parent, 0,
 					  NETLINK_CB(cb->skb).portid,
 					  cb->nlh->nlmsg_seq, NLM_F_MULTI,
 					  RTM_NEWTFILTER) <= 0)
@@ -991,6 +1310,7 @@ static bool tcf_chain_dump(struct tcf_chain *chain, struct Qdisc *q, u32 parent,
 		arg.w.fn = tcf_node_dump;
 		arg.skb = skb;
 		arg.cb = cb;
+		arg.block = block;
 		arg.q = q;
 		arg.parent = parent;
 		arg.w.stop = 0;
@@ -1009,13 +1329,10 @@ static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	struct net *net = sock_net(skb->sk);
 	struct nlattr *tca[TCA_MAX + 1];
-	struct net_device *dev;
-	struct Qdisc *q;
+	struct Qdisc *q = NULL;
 	struct tcf_block *block;
 	struct tcf_chain *chain;
 	struct tcmsg *tcm = nlmsg_data(cb->nlh);
-	unsigned long cl = 0;
-	const struct Qdisc_class_ops *cops;
 	long index_start;
 	long index;
 	u32 parent;
@@ -1028,32 +1345,51 @@ static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb)
 	if (err)
 		return err;
 
-	dev = __dev_get_by_index(net, tcm->tcm_ifindex);
-	if (!dev)
-		return skb->len;
-
-	parent = tcm->tcm_parent;
-	if (!parent) {
-		q = dev->qdisc;
-		parent = q->handle;
+	if (tcm->tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK) {
+		block = tcf_block_lookup(net, tcm->tcm_block_index);
+		if (!block)
+			goto out;
+		/* If we work with block index, q is NULL and parent value
+		 * will never be used in the following code. The check
+		 * in tcf_fill_node prevents it. However, compiler does not
+		 * see that far, so set parent to zero to silence the warning
+		 * about parent being uninitialized.
+		 */
+		parent = 0;
 	} else {
-		q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
-	}
-	if (!q)
-		goto out;
-	cops = q->ops->cl_ops;
-	if (!cops)
-		goto out;
-	if (!cops->tcf_block)
-		goto out;
-	if (TC_H_MIN(tcm->tcm_parent)) {
-		cl = cops->find(q, tcm->tcm_parent);
-		if (cl == 0)
+		const struct Qdisc_class_ops *cops;
+		struct net_device *dev;
+		unsigned long cl = 0;
+
+		dev = __dev_get_by_index(net, tcm->tcm_ifindex);
+		if (!dev)
+			return skb->len;
+
+		parent = tcm->tcm_parent;
+		if (!parent) {
+			q = dev->qdisc;
+			parent = q->handle;
+		} else {
+			q = qdisc_lookup(dev, TC_H_MAJ(tcm->tcm_parent));
+		}
+		if (!q)
+			goto out;
+		cops = q->ops->cl_ops;
+		if (!cops)
+			goto out;
+		if (!cops->tcf_block)
+			goto out;
+		if (TC_H_MIN(tcm->tcm_parent)) {
+			cl = cops->find(q, tcm->tcm_parent);
+			if (cl == 0)
+				goto out;
+		}
+		block = cops->tcf_block(q, cl, NULL);
+		if (!block)
 			goto out;
+		if (tcf_block_shared(block))
+			q = NULL;
 	}
-	block = cops->tcf_block(q, cl);
-	if (!block)
-		goto out;
 
 	index_start = cb->args[0];
 	index = 0;
@@ -1088,7 +1424,8 @@ void tcf_exts_destroy(struct tcf_exts *exts)
 EXPORT_SYMBOL(tcf_exts_destroy);
 
 int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb,
-		      struct nlattr *rate_tlv, struct tcf_exts *exts, bool ovr)
+		      struct nlattr *rate_tlv, struct tcf_exts *exts, bool ovr,
+		      struct netlink_ext_ack *extack)
 {
 #ifdef CONFIG_NET_CLS_ACT
 	{
@@ -1121,8 +1458,10 @@ int tcf_exts_validate(struct net *net, struct tcf_proto *tp, struct nlattr **tb,
 	}
 #else
 	if ((exts->action && tb[exts->action]) ||
-	    (exts->police && tb[exts->police]))
+	    (exts->police && tb[exts->police])) {
+		NL_SET_ERR_MSG(extack, "Classifier actions are not supported per compile options (CONFIG_NET_CLS_ACT)");
 		return -EOPNOTSUPP;
+	}
 #endif
 
 	return 0;
@@ -1256,18 +1595,50 @@ int tc_setup_cb_call(struct tcf_block *block, struct tcf_exts *exts,
 }
 EXPORT_SYMBOL(tc_setup_cb_call);
 
+static __net_init int tcf_net_init(struct net *net)
+{
+	struct tcf_net *tn = net_generic(net, tcf_net_id);
+
+	idr_init(&tn->idr);
+	return 0;
+}
+
+static void __net_exit tcf_net_exit(struct net *net)
+{
+	struct tcf_net *tn = net_generic(net, tcf_net_id);
+
+	idr_destroy(&tn->idr);
+}
+
+static struct pernet_operations tcf_net_ops = {
+	.init = tcf_net_init,
+	.exit = tcf_net_exit,
+	.id   = &tcf_net_id,
+	.size = sizeof(struct tcf_net),
+};
+
 static int __init tc_filter_init(void)
 {
+	int err;
+
 	tc_filter_wq = alloc_ordered_workqueue("tc_filter_workqueue", 0);
 	if (!tc_filter_wq)
 		return -ENOMEM;
 
+	err = register_pernet_subsys(&tcf_net_ops);
+	if (err)
+		goto err_register_pernet_subsys;
+
 	rtnl_register(PF_UNSPEC, RTM_NEWTFILTER, tc_ctl_tfilter, NULL, 0);
 	rtnl_register(PF_UNSPEC, RTM_DELTFILTER, tc_ctl_tfilter, NULL, 0);
 	rtnl_register(PF_UNSPEC, RTM_GETTFILTER, tc_ctl_tfilter,
 		      tc_dump_tfilter, 0);
 
 	return 0;
+
+err_register_pernet_subsys:
+	destroy_workqueue(tc_filter_wq);
+	return err;
 }
 
 subsys_initcall(tc_filter_init);