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-rw-r--r--net/sched/cls_api.c144
1 files changed, 104 insertions, 40 deletions
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 5f7098b5405e..194c2e0b2737 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -232,19 +232,6 @@ static void tcf_chain0_head_change(struct tcf_chain *chain,
tcf_chain_head_change_item(item, tp_head);
}
-static void tcf_chain_flush(struct tcf_chain *chain)
-{
- struct tcf_proto *tp = rtnl_dereference(chain->filter_chain);
-
- tcf_chain0_head_change(chain, NULL);
- while (tp) {
- RCU_INIT_POINTER(chain->filter_chain, tp->next);
- tcf_proto_destroy(tp, NULL);
- tp = rtnl_dereference(chain->filter_chain);
- tcf_chain_put(chain);
- }
-}
-
static void tcf_chain_destroy(struct tcf_chain *chain)
{
struct tcf_block *block = chain->block;
@@ -262,6 +249,14 @@ static void tcf_chain_hold(struct tcf_chain *chain)
++chain->refcnt;
}
+static bool tcf_chain_held_by_acts_only(struct tcf_chain *chain)
+{
+ /* In case all the references are action references, this
+ * chain should not be shown to the user.
+ */
+ return chain->refcnt == chain->action_refcnt;
+}
+
static struct tcf_chain *tcf_chain_lookup(struct tcf_block *block,
u32 chain_index)
{
@@ -277,38 +272,77 @@ static struct tcf_chain *tcf_chain_lookup(struct tcf_block *block,
static int tc_chain_notify(struct tcf_chain *chain, struct sk_buff *oskb,
u32 seq, u16 flags, int event, bool unicast);
-struct tcf_chain *tcf_chain_get(struct tcf_block *block, u32 chain_index,
- bool create)
+static struct tcf_chain *__tcf_chain_get(struct tcf_block *block,
+ u32 chain_index, bool create,
+ bool by_act)
{
struct tcf_chain *chain = tcf_chain_lookup(block, chain_index);
if (chain) {
tcf_chain_hold(chain);
- return chain;
+ } else {
+ if (!create)
+ return NULL;
+ chain = tcf_chain_create(block, chain_index);
+ if (!chain)
+ return NULL;
}
- if (!create)
- return NULL;
- chain = tcf_chain_create(block, chain_index);
- if (!chain)
- return NULL;
- tc_chain_notify(chain, NULL, 0, NLM_F_CREATE | NLM_F_EXCL,
- RTM_NEWCHAIN, false);
+ if (by_act)
+ ++chain->action_refcnt;
+
+ /* Send notification only in case we got the first
+ * non-action reference. Until then, the chain acts only as
+ * a placeholder for actions pointing to it and user ought
+ * not know about them.
+ */
+ if (chain->refcnt - chain->action_refcnt == 1 && !by_act)
+ tc_chain_notify(chain, NULL, 0, NLM_F_CREATE | NLM_F_EXCL,
+ RTM_NEWCHAIN, false);
+
return chain;
}
-EXPORT_SYMBOL(tcf_chain_get);
+
+static struct tcf_chain *tcf_chain_get(struct tcf_block *block, u32 chain_index,
+ bool create)
+{
+ return __tcf_chain_get(block, chain_index, create, false);
+}
+
+struct tcf_chain *tcf_chain_get_by_act(struct tcf_block *block, u32 chain_index)
+{
+ return __tcf_chain_get(block, chain_index, true, true);
+}
+EXPORT_SYMBOL(tcf_chain_get_by_act);
static void tc_chain_tmplt_del(struct tcf_chain *chain);
-void tcf_chain_put(struct tcf_chain *chain)
+static void __tcf_chain_put(struct tcf_chain *chain, bool by_act)
{
- if (--chain->refcnt == 0) {
+ if (by_act)
+ chain->action_refcnt--;
+ chain->refcnt--;
+
+ /* The last dropped non-action reference will trigger notification. */
+ if (chain->refcnt - chain->action_refcnt == 0 && !by_act)
tc_chain_notify(chain, NULL, 0, 0, RTM_DELCHAIN, false);
+
+ if (chain->refcnt == 0) {
tc_chain_tmplt_del(chain);
tcf_chain_destroy(chain);
}
}
-EXPORT_SYMBOL(tcf_chain_put);
+
+static void tcf_chain_put(struct tcf_chain *chain)
+{
+ __tcf_chain_put(chain, false);
+}
+
+void tcf_chain_put_by_act(struct tcf_chain *chain)
+{
+ __tcf_chain_put(chain, true);
+}
+EXPORT_SYMBOL(tcf_chain_put_by_act);
static void tcf_chain_put_explicitly_created(struct tcf_chain *chain)
{
@@ -316,6 +350,19 @@ static void tcf_chain_put_explicitly_created(struct tcf_chain *chain)
tcf_chain_put(chain);
}
+static void tcf_chain_flush(struct tcf_chain *chain)
+{
+ struct tcf_proto *tp = rtnl_dereference(chain->filter_chain);
+
+ tcf_chain0_head_change(chain, NULL);
+ while (tp) {
+ RCU_INIT_POINTER(chain->filter_chain, tp->next);
+ tcf_proto_destroy(tp, NULL);
+ tp = rtnl_dereference(chain->filter_chain);
+ tcf_chain_put(chain);
+ }
+}
+
static bool tcf_block_offload_in_use(struct tcf_block *block)
{
return block->offloadcnt;
@@ -1342,6 +1389,13 @@ static int tc_del_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
}
chain = tcf_chain_get(block, chain_index, false);
if (!chain) {
+ /* User requested flush on non-existent chain. Nothing to do,
+ * so just return success.
+ */
+ if (prio == 0) {
+ err = 0;
+ goto errout;
+ }
NL_SET_ERR_MSG(extack, "Cannot find specified filter chain");
err = -EINVAL;
goto errout;
@@ -1803,20 +1857,28 @@ replay:
chain = tcf_chain_lookup(block, chain_index);
if (n->nlmsg_type == RTM_NEWCHAIN) {
if (chain) {
- NL_SET_ERR_MSG(extack, "Filter chain already exists");
- return -EEXIST;
- }
- if (!(n->nlmsg_flags & NLM_F_CREATE)) {
- NL_SET_ERR_MSG(extack, "Need both RTM_NEWCHAIN and NLM_F_CREATE to create a new chain");
- return -ENOENT;
- }
- chain = tcf_chain_create(block, chain_index);
- if (!chain) {
- NL_SET_ERR_MSG(extack, "Failed to create filter chain");
- return -ENOMEM;
+ if (tcf_chain_held_by_acts_only(chain)) {
+ /* The chain exists only because there is
+ * some action referencing it.
+ */
+ tcf_chain_hold(chain);
+ } else {
+ NL_SET_ERR_MSG(extack, "Filter chain already exists");
+ return -EEXIST;
+ }
+ } else {
+ if (!(n->nlmsg_flags & NLM_F_CREATE)) {
+ NL_SET_ERR_MSG(extack, "Need both RTM_NEWCHAIN and NLM_F_CREATE to create a new chain");
+ return -ENOENT;
+ }
+ chain = tcf_chain_create(block, chain_index);
+ if (!chain) {
+ NL_SET_ERR_MSG(extack, "Failed to create filter chain");
+ return -ENOMEM;
+ }
}
} else {
- if (!chain) {
+ if (!chain || tcf_chain_held_by_acts_only(chain)) {
NL_SET_ERR_MSG(extack, "Cannot find specified filter chain");
return -EINVAL;
}
@@ -1844,9 +1906,9 @@ replay:
* to the chain previously taken during addition.
*/
tcf_chain_put_explicitly_created(chain);
+ chain->explicitly_created = false;
break;
case RTM_GETCHAIN:
- break;
err = tc_chain_notify(chain, skb, n->nlmsg_seq,
n->nlmsg_seq, n->nlmsg_type, true);
if (err < 0)
@@ -1944,6 +2006,8 @@ static int tc_dump_chain(struct sk_buff *skb, struct netlink_callback *cb)
index++;
continue;
}
+ if (tcf_chain_held_by_acts_only(chain))
+ continue;
err = tc_chain_fill_node(chain, net, skb, block,
NETLINK_CB(cb->skb).portid,
cb->nlh->nlmsg_seq, NLM_F_MULTI,
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.