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cls_api.c
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* net/sched/cls_api.c Packet classifier API.
*
* Authors: Alexey Kuznetsov, <[email protected]>
*
* Changes:
*
* Eduardo J. Blanco <[email protected]> :990222: kmod support
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/kmod.h>
#include <linux/slab.h>
#include <linux/idr.h>
#include <linux/jhash.h>
#include <linux/rculist.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <net/pkt_cls.h>
#include <net/tc_act/tc_pedit.h>
#include <net/tc_act/tc_mirred.h>
#include <net/tc_act/tc_vlan.h>
#include <net/tc_act/tc_tunnel_key.h>
#include <net/tc_act/tc_csum.h>
#include <net/tc_act/tc_gact.h>
#include <net/tc_act/tc_police.h>
#include <net/tc_act/tc_sample.h>
#include <net/tc_act/tc_skbedit.h>
#include <net/tc_act/tc_ct.h>
#include <net/tc_act/tc_mpls.h>
#include <net/tc_act/tc_gate.h>
#include <net/flow_offload.h>
extern const struct nla_policy rtm_tca_policy[TCA_MAX + 1];
/* The list of all installed classifier types */
static LIST_HEAD(tcf_proto_base);
/* Protects list of registered TC modules. It is pure SMP lock. */
static DEFINE_RWLOCK(cls_mod_lock);
static u32 destroy_obj_hashfn(const struct tcf_proto *tp)
{
return jhash_3words(tp->chain->index, tp->prio,
(__force __u32)tp->protocol, 0);
}
static void tcf_proto_signal_destroying(struct tcf_chain *chain,
struct tcf_proto *tp)
{
struct tcf_block *block = chain->block;
mutex_lock(&block->proto_destroy_lock);
hash_add_rcu(block->proto_destroy_ht, &tp->destroy_ht_node,
destroy_obj_hashfn(tp));
mutex_unlock(&block->proto_destroy_lock);
}
static bool tcf_proto_cmp(const struct tcf_proto *tp1,
const struct tcf_proto *tp2)
{
return tp1->chain->index == tp2->chain->index &&
tp1->prio == tp2->prio &&
tp1->protocol == tp2->protocol;
}
static bool tcf_proto_exists_destroying(struct tcf_chain *chain,
struct tcf_proto *tp)
{
u32 hash = destroy_obj_hashfn(tp);
struct tcf_proto *iter;
bool found = false;
rcu_read_lock();
hash_for_each_possible_rcu(chain->block->proto_destroy_ht, iter,
destroy_ht_node, hash) {
if (tcf_proto_cmp(tp, iter)) {
found = true;
break;
}
}
rcu_read_unlock();
return found;
}
static void
tcf_proto_signal_destroyed(struct tcf_chain *chain, struct tcf_proto *tp)
{
struct tcf_block *block = chain->block;
mutex_lock(&block->proto_destroy_lock);
if (hash_hashed(&tp->destroy_ht_node))
hash_del_rcu(&tp->destroy_ht_node);
mutex_unlock(&block->proto_destroy_lock);
}
/* Find classifier type by string name */
static const struct tcf_proto_ops *__tcf_proto_lookup_ops(const char *kind)
{
const struct tcf_proto_ops *t, *res = NULL;
if (kind) {
read_lock(&cls_mod_lock);
list_for_each_entry(t, &tcf_proto_base, head) {
if (strcmp(kind, t->kind) == 0) {
if (try_module_get(t->owner))
res = t;
break;
}
}
read_unlock(&cls_mod_lock);
}
return res;
}
static const struct tcf_proto_ops *
tcf_proto_lookup_ops(const char *kind, bool rtnl_held,
struct netlink_ext_ack *extack)
{
const struct tcf_proto_ops *ops;
ops = __tcf_proto_lookup_ops(kind);
if (ops)
return ops;
#ifdef CONFIG_MODULES
if (rtnl_held)
rtnl_unlock();
request_module("cls_%s", kind);
if (rtnl_held)
rtnl_lock();
ops = __tcf_proto_lookup_ops(kind);
/* We dropped the RTNL semaphore in order to perform
* the module load. So, even if we succeeded in loading
* the module we have to replay the request. We indicate
* this using -EAGAIN.
*/
if (ops) {
module_put(ops->owner);
return ERR_PTR(-EAGAIN);
}
#endif
NL_SET_ERR_MSG(extack, "TC classifier not found");
return ERR_PTR(-ENOENT);
}
/* Register(unregister) new classifier type */
int register_tcf_proto_ops(struct tcf_proto_ops *ops)
{
struct tcf_proto_ops *t;
int rc = -EEXIST;
write_lock(&cls_mod_lock);
list_for_each_entry(t, &tcf_proto_base, head)
if (!strcmp(ops->kind, t->kind))
goto out;
list_add_tail(&ops->head, &tcf_proto_base);
rc = 0;
out:
write_unlock(&cls_mod_lock);
return rc;
}
EXPORT_SYMBOL(register_tcf_proto_ops);
static struct workqueue_struct *tc_filter_wq;
int unregister_tcf_proto_ops(struct tcf_proto_ops *ops)
{
struct tcf_proto_ops *t;
int rc = -ENOENT;
/* Wait for outstanding call_rcu()s, if any, from a
* tcf_proto_ops's destroy() handler.
*/
rcu_barrier();
flush_workqueue(tc_filter_wq);
write_lock(&cls_mod_lock);
list_for_each_entry(t, &tcf_proto_base, head) {
if (t == ops) {
list_del(&t->head);
rc = 0;
break;
}
}
write_unlock(&cls_mod_lock);
return rc;
}
EXPORT_SYMBOL(unregister_tcf_proto_ops);
bool tcf_queue_work(struct rcu_work *rwork, work_func_t func)
{
INIT_RCU_WORK(rwork, func);
return queue_rcu_work(tc_filter_wq, rwork);
}
EXPORT_SYMBOL(tcf_queue_work);
/* Select new prio value from the range, managed by kernel. */
static inline u32 tcf_auto_prio(struct tcf_proto *tp)
{
u32 first = TC_H_MAKE(0xC0000000U, 0U);
if (tp)
first = tp->prio - 1;
return TC_H_MAJ(first);
}
static bool tcf_proto_check_kind(struct nlattr *kind, char *name)
{
if (kind)
return nla_strscpy(name, kind, IFNAMSIZ) < 0;
memset(name, 0, IFNAMSIZ);
return false;
}
static bool tcf_proto_is_unlocked(const char *kind)
{
const struct tcf_proto_ops *ops;
bool ret;
if (strlen(kind) == 0)
return false;
ops = tcf_proto_lookup_ops(kind, false, NULL);
/* On error return false to take rtnl lock. Proto lookup/create
* functions will perform lookup again and properly handle errors.
*/
if (IS_ERR(ops))
return false;
ret = !!(ops->flags & TCF_PROTO_OPS_DOIT_UNLOCKED);
module_put(ops->owner);
return ret;
}
static struct tcf_proto *tcf_proto_create(const char *kind, u32 protocol,
u32 prio, struct tcf_chain *chain,
bool rtnl_held,
struct netlink_ext_ack *extack)
{
struct tcf_proto *tp;
int err;
tp = kzalloc(sizeof(*tp), GFP_KERNEL);
if (!tp)
return ERR_PTR(-ENOBUFS);
tp->ops = tcf_proto_lookup_ops(kind, rtnl_held, extack);
if (IS_ERR(tp->ops)) {
err = PTR_ERR(tp->ops);
goto errout;
}
tp->classify = tp->ops->classify;
tp->protocol = protocol;
tp->prio = prio;
tp->chain = chain;
spin_lock_init(&tp->lock);
refcount_set(&tp->refcnt, 1);
err = tp->ops->init(tp);
if (err) {
module_put(tp->ops->owner);
goto errout;
}
return tp;
errout:
kfree(tp);
return ERR_PTR(err);
}
static void tcf_proto_get(struct tcf_proto *tp)
{
refcount_inc(&tp->refcnt);
}
static void tcf_chain_put(struct tcf_chain *chain);
static void tcf_proto_destroy(struct tcf_proto *tp, bool rtnl_held,
bool sig_destroy, struct netlink_ext_ack *extack)
{
tp->ops->destroy(tp, rtnl_held, extack);
if (sig_destroy)
tcf_proto_signal_destroyed(tp->chain, tp);
tcf_chain_put(tp->chain);
module_put(tp->ops->owner);
kfree_rcu(tp, rcu);
}
static void tcf_proto_put(struct tcf_proto *tp, bool rtnl_held,
struct netlink_ext_ack *extack)
{
if (refcount_dec_and_test(&tp->refcnt))
tcf_proto_destroy(tp, rtnl_held, true, extack);
}
static bool tcf_proto_check_delete(struct tcf_proto *tp)
{
if (tp->ops->delete_empty)
return tp->ops->delete_empty(tp);
tp->deleting = true;
return tp->deleting;
}
static void tcf_proto_mark_delete(struct tcf_proto *tp)
{
spin_lock(&tp->lock);
tp->deleting = true;
spin_unlock(&tp->lock);
}
static bool tcf_proto_is_deleting(struct tcf_proto *tp)
{
bool deleting;
spin_lock(&tp->lock);
deleting = tp->deleting;
spin_unlock(&tp->lock);
return deleting;
}
#define ASSERT_BLOCK_LOCKED(block) \
lockdep_assert_held(&(block)->lock)
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)
{
struct tcf_chain *chain;
ASSERT_BLOCK_LOCKED(block);
chain = kzalloc(sizeof(*chain), GFP_KERNEL);
if (!chain)
return NULL;
list_add_tail_rcu(&chain->list, &block->chain_list);
mutex_init(&chain->filter_chain_lock);
chain->block = block;
chain->index = chain_index;
chain->refcnt = 1;
if (!chain->index)
block->chain0.chain = chain;
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_chain0_head_change(struct tcf_chain *chain,
struct tcf_proto *tp_head)
{
struct tcf_filter_chain_list_item *item;
struct tcf_block *block = chain->block;
if (chain->index)
return;
mutex_lock(&block->lock);
list_for_each_entry(item, &block->chain0.filter_chain_list, list)
tcf_chain_head_change_item(item, tp_head);
mutex_unlock(&block->lock);
}
/* Returns true if block can be safely freed. */
static bool tcf_chain_detach(struct tcf_chain *chain)
{
struct tcf_block *block = chain->block;
ASSERT_BLOCK_LOCKED(block);
list_del_rcu(&chain->list);
if (!chain->index)
block->chain0.chain = NULL;
if (list_empty(&block->chain_list) &&
refcount_read(&block->refcnt) == 0)
return true;
return false;
}
static void tcf_block_destroy(struct tcf_block *block)
{
mutex_destroy(&block->lock);
mutex_destroy(&block->proto_destroy_lock);
kfree_rcu(block, rcu);
}
static void tcf_chain_destroy(struct tcf_chain *chain, bool free_block)
{
struct tcf_block *block = chain->block;
mutex_destroy(&chain->filter_chain_lock);
kfree_rcu(chain, rcu);
if (free_block)
tcf_block_destroy(block);
}
static void tcf_chain_hold(struct tcf_chain *chain)
{
ASSERT_BLOCK_LOCKED(chain->block);
++chain->refcnt;
}
static bool tcf_chain_held_by_acts_only(struct tcf_chain *chain)
{
ASSERT_BLOCK_LOCKED(chain->block);
/* 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)
{
struct tcf_chain *chain;
ASSERT_BLOCK_LOCKED(block);
list_for_each_entry(chain, &block->chain_list, list) {
if (chain->index == chain_index)
return chain;
}
return NULL;
}
#if IS_ENABLED(CONFIG_NET_TC_SKB_EXT)
static struct tcf_chain *tcf_chain_lookup_rcu(const struct tcf_block *block,
u32 chain_index)
{
struct tcf_chain *chain;
list_for_each_entry_rcu(chain, &block->chain_list, list) {
if (chain->index == chain_index)
return chain;
}
return NULL;
}
#endif
static int tc_chain_notify(struct tcf_chain *chain, struct sk_buff *oskb,
u32 seq, u16 flags, int event, bool unicast);
static struct tcf_chain *__tcf_chain_get(struct tcf_block *block,
u32 chain_index, bool create,
bool by_act)
{
struct tcf_chain *chain = NULL;
bool is_first_reference;
mutex_lock(&block->lock);
chain = tcf_chain_lookup(block, chain_index);
if (chain) {
tcf_chain_hold(chain);
} else {
if (!create)
goto errout;
chain = tcf_chain_create(block, chain_index);
if (!chain)
goto errout;
}
if (by_act)
++chain->action_refcnt;
is_first_reference = chain->refcnt - chain->action_refcnt == 1;
mutex_unlock(&block->lock);
/* 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 (is_first_reference && !by_act)
tc_chain_notify(chain, NULL, 0, NLM_F_CREATE | NLM_F_EXCL,
RTM_NEWCHAIN, false);
return chain;
errout:
mutex_unlock(&block->lock);
return chain;
}
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(const struct tcf_proto_ops *tmplt_ops,
void *tmplt_priv);
static int tc_chain_notify_delete(const struct tcf_proto_ops *tmplt_ops,
void *tmplt_priv, u32 chain_index,
struct tcf_block *block, struct sk_buff *oskb,
u32 seq, u16 flags, bool unicast);
static void __tcf_chain_put(struct tcf_chain *chain, bool by_act,
bool explicitly_created)
{
struct tcf_block *block = chain->block;
const struct tcf_proto_ops *tmplt_ops;
bool free_block = false;
unsigned int refcnt;
void *tmplt_priv;
mutex_lock(&block->lock);
if (explicitly_created) {
if (!chain->explicitly_created) {
mutex_unlock(&block->lock);
return;
}
chain->explicitly_created = false;
}
if (by_act)
chain->action_refcnt--;
/* tc_chain_notify_delete can't be called while holding block lock.
* However, when block is unlocked chain can be changed concurrently, so
* save these to temporary variables.
*/
refcnt = --chain->refcnt;
tmplt_ops = chain->tmplt_ops;
tmplt_priv = chain->tmplt_priv;
/* The last dropped non-action reference will trigger notification. */
if (refcnt - chain->action_refcnt == 0 && !by_act) {
tc_chain_notify_delete(tmplt_ops, tmplt_priv, chain->index,
block, NULL, 0, 0, false);
/* Last reference to chain, no need to lock. */
chain->flushing = false;
}
if (refcnt == 0)
free_block = tcf_chain_detach(chain);
mutex_unlock(&block->lock);
if (refcnt == 0) {
tc_chain_tmplt_del(tmplt_ops, tmplt_priv);
tcf_chain_destroy(chain, free_block);
}
}
static void tcf_chain_put(struct tcf_chain *chain)
{
__tcf_chain_put(chain, false, false);
}
void tcf_chain_put_by_act(struct tcf_chain *chain)
{
__tcf_chain_put(chain, true, false);
}
EXPORT_SYMBOL(tcf_chain_put_by_act);
static void tcf_chain_put_explicitly_created(struct tcf_chain *chain)
{
__tcf_chain_put(chain, false, true);
}
static void tcf_chain_flush(struct tcf_chain *chain, bool rtnl_held)
{
struct tcf_proto *tp, *tp_next;
mutex_lock(&chain->filter_chain_lock);
tp = tcf_chain_dereference(chain->filter_chain, chain);
while (tp) {
tp_next = rcu_dereference_protected(tp->next, 1);
tcf_proto_signal_destroying(chain, tp);
tp = tp_next;
}
tp = tcf_chain_dereference(chain->filter_chain, chain);
RCU_INIT_POINTER(chain->filter_chain, NULL);
tcf_chain0_head_change(chain, NULL);
chain->flushing = true;
mutex_unlock(&chain->filter_chain_lock);
while (tp) {
tp_next = rcu_dereference_protected(tp->next, 1);
tcf_proto_put(tp, rtnl_held, NULL);
tp = tp_next;
}
}
static int tcf_block_setup(struct tcf_block *block,
struct flow_block_offload *bo);
static void tcf_block_offload_init(struct flow_block_offload *bo,
struct net_device *dev, struct Qdisc *sch,
enum flow_block_command command,
enum flow_block_binder_type binder_type,
struct flow_block *flow_block,
bool shared, struct netlink_ext_ack *extack)
{
bo->net = dev_net(dev);
bo->command = command;
bo->binder_type = binder_type;
bo->block = flow_block;
bo->block_shared = shared;
bo->extack = extack;
bo->sch = sch;
INIT_LIST_HEAD(&bo->cb_list);
}
static void tcf_block_unbind(struct tcf_block *block,
struct flow_block_offload *bo);
static void tc_block_indr_cleanup(struct flow_block_cb *block_cb)
{
struct tcf_block *block = block_cb->indr.data;
struct net_device *dev = block_cb->indr.dev;
struct Qdisc *sch = block_cb->indr.sch;
struct netlink_ext_ack extack = {};
struct flow_block_offload bo;
tcf_block_offload_init(&bo, dev, sch, FLOW_BLOCK_UNBIND,
block_cb->indr.binder_type,
&block->flow_block, tcf_block_shared(block),
&extack);
rtnl_lock();
down_write(&block->cb_lock);
list_del(&block_cb->driver_list);
list_move(&block_cb->list, &bo.cb_list);
tcf_block_unbind(block, &bo);
up_write(&block->cb_lock);
rtnl_unlock();
}
static bool tcf_block_offload_in_use(struct tcf_block *block)
{
return atomic_read(&block->offloadcnt);
}
static int tcf_block_offload_cmd(struct tcf_block *block,
struct net_device *dev, struct Qdisc *sch,
struct tcf_block_ext_info *ei,
enum flow_block_command command,
struct netlink_ext_ack *extack)
{
struct flow_block_offload bo = {};
tcf_block_offload_init(&bo, dev, sch, command, ei->binder_type,
&block->flow_block, tcf_block_shared(block),
extack);
if (dev->netdev_ops->ndo_setup_tc) {
int err;
err = dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_BLOCK, &bo);
if (err < 0) {
if (err != -EOPNOTSUPP)
NL_SET_ERR_MSG(extack, "Driver ndo_setup_tc failed");
return err;
}
return tcf_block_setup(block, &bo);
}
flow_indr_dev_setup_offload(dev, sch, TC_SETUP_BLOCK, block, &bo,
tc_block_indr_cleanup);
tcf_block_setup(block, &bo);
return -EOPNOTSUPP;
}
static int tcf_block_offload_bind(struct tcf_block *block, struct Qdisc *q,
struct tcf_block_ext_info *ei,
struct netlink_ext_ack *extack)
{
struct net_device *dev = q->dev_queue->dev;
int err;
down_write(&block->cb_lock);
/* If tc offload feature is disabled and the block we try to bind
* to already has some offloaded filters, forbid to bind.
*/
if (dev->netdev_ops->ndo_setup_tc &&
!tc_can_offload(dev) &&
tcf_block_offload_in_use(block)) {
NL_SET_ERR_MSG(extack, "Bind to offloaded block failed as dev has offload disabled");
err = -EOPNOTSUPP;
goto err_unlock;
}
err = tcf_block_offload_cmd(block, dev, q, ei, FLOW_BLOCK_BIND, extack);
if (err == -EOPNOTSUPP)
goto no_offload_dev_inc;
if (err)
goto err_unlock;
up_write(&block->cb_lock);
return 0;
no_offload_dev_inc:
if (tcf_block_offload_in_use(block))
goto err_unlock;
err = 0;
block->nooffloaddevcnt++;
err_unlock:
up_write(&block->cb_lock);
return err;
}
static void tcf_block_offload_unbind(struct tcf_block *block, struct Qdisc *q,
struct tcf_block_ext_info *ei)
{
struct net_device *dev = q->dev_queue->dev;
int err;
down_write(&block->cb_lock);
err = tcf_block_offload_cmd(block, dev, q, ei, FLOW_BLOCK_UNBIND, NULL);
if (err == -EOPNOTSUPP)
goto no_offload_dev_dec;
up_write(&block->cb_lock);
return;
no_offload_dev_dec:
WARN_ON(block->nooffloaddevcnt-- == 0);
up_write(&block->cb_lock);
}
static int
tcf_chain0_head_change_cb_add(struct tcf_block *block,
struct tcf_block_ext_info *ei,
struct netlink_ext_ack *extack)
{
struct tcf_filter_chain_list_item *item;
struct tcf_chain *chain0;
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;
mutex_lock(&block->lock);
chain0 = block->chain0.chain;
if (chain0)
tcf_chain_hold(chain0);
else
list_add(&item->list, &block->chain0.filter_chain_list);
mutex_unlock(&block->lock);
if (chain0) {
struct tcf_proto *tp_head;
mutex_lock(&chain0->filter_chain_lock);
tp_head = tcf_chain_dereference(chain0->filter_chain, chain0);
if (tp_head)
tcf_chain_head_change_item(item, tp_head);
mutex_lock(&block->lock);
list_add(&item->list, &block->chain0.filter_chain_list);
mutex_unlock(&block->lock);
mutex_unlock(&chain0->filter_chain_lock);
tcf_chain_put(chain0);
}
return 0;
}
static void
tcf_chain0_head_change_cb_del(struct tcf_block *block,
struct tcf_block_ext_info *ei)
{
struct tcf_filter_chain_list_item *item;
mutex_lock(&block->lock);
list_for_each_entry(item, &block->chain0.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)) {
if (block->chain0.chain)
tcf_chain_head_change_item(item, NULL);
list_del(&item->list);
mutex_unlock(&block->lock);
kfree(item);
return;
}
}
mutex_unlock(&block->lock);
WARN_ON(1);
}
struct tcf_net {
spinlock_t idr_lock; /* Protects idr */
struct idr idr;
};
static unsigned int tcf_net_id;
static int tcf_block_insert(struct tcf_block *block, struct net *net,
struct netlink_ext_ack *extack)
{
struct tcf_net *tn = net_generic(net, tcf_net_id);
int err;
idr_preload(GFP_KERNEL);
spin_lock(&tn->idr_lock);
err = idr_alloc_u32(&tn->idr, block, &block->index, block->index,
GFP_NOWAIT);
spin_unlock(&tn->idr_lock);
idr_preload_end();
return err;
}
static void tcf_block_remove(struct tcf_block *block, struct net *net)
{
struct tcf_net *tn = net_generic(net, tcf_net_id);
spin_lock(&tn->idr_lock);
idr_remove(&tn->idr, block->index);
spin_unlock(&tn->idr_lock);
}
static struct tcf_block *tcf_block_create(struct net *net, struct Qdisc *q,
u32 block_index,
struct netlink_ext_ack *extack)
{
struct tcf_block *block;
block = kzalloc(sizeof(*block), GFP_KERNEL);
if (!block) {
NL_SET_ERR_MSG(extack, "Memory allocation for block failed");
return ERR_PTR(-ENOMEM);
}
mutex_init(&block->lock);
mutex_init(&block->proto_destroy_lock);
init_rwsem(&block->cb_lock);
flow_block_init(&block->flow_block);
INIT_LIST_HEAD(&block->chain_list);
INIT_LIST_HEAD(&block->owner_list);
INIT_LIST_HEAD(&block->chain0.filter_chain_list);
refcount_set(&block->refcnt, 1);
block->net = net;
block->index = block_index;
/* Don't store q pointer for blocks which are shared */
if (!tcf_block_shared(block))
block->q = q;
return block;
}
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(&tn->idr, block_index);
}
static struct tcf_block *tcf_block_refcnt_get(struct net *net, u32 block_index)
{
struct tcf_block *block;
rcu_read_lock();
block = tcf_block_lookup(net, block_index);
if (block && !refcount_inc_not_zero(&block->refcnt))
block = NULL;
rcu_read_unlock();
return block;
}
static struct tcf_chain *
__tcf_get_next_chain(struct tcf_block *block, struct tcf_chain *chain)
{
mutex_lock(&block->lock);
if (chain)
chain = list_is_last(&chain->list, &block->chain_list) ?
NULL : list_next_entry(chain, list);
else
chain = list_first_entry_or_null(&block->chain_list,
struct tcf_chain, list);
/* skip all action-only chains */
while (chain && tcf_chain_held_by_acts_only(chain))
chain = list_is_last(&chain->list, &block->chain_list) ?
NULL : list_next_entry(chain, list);
if (chain)
tcf_chain_hold(chain);
mutex_unlock(&block->lock);
return chain;
}
/* Function to be used by all clients that want to iterate over all chains on
* block. It properly obtains block->lock and takes reference to chain before
* returning it. Users of this function must be tolerant to concurrent chain
* insertion/deletion or ensure that no concurrent chain modification is
* possible. Note that all netlink dump callbacks cannot guarantee to provide
* consistent dump because rtnl lock is released each time skb is filled with
* data and sent to user-space.
*/
struct tcf_chain *
tcf_get_next_chain(struct tcf_block *block, struct tcf_chain *chain)
{
struct tcf_chain *chain_next = __tcf_get_next_chain(block, chain);
if (chain)
tcf_chain_put(chain);
return chain_next;
}
EXPORT_SYMBOL(tcf_get_next_chain);
static struct tcf_proto *
__tcf_get_next_proto(struct tcf_chain *chain, struct tcf_proto *tp)
{
u32 prio = 0;
ASSERT_RTNL();
mutex_lock(&chain->filter_chain_lock);
if (!tp) {
tp = tcf_chain_dereference(chain->filter_chain, chain);
} else if (tcf_proto_is_deleting(tp)) {
/* 'deleting' flag is set and chain->filter_chain_lock was
* unlocked, which means next pointer could be invalid. Restart
* search.
*/
prio = tp->prio + 1;
tp = tcf_chain_dereference(chain->filter_chain, chain);
for (; tp; tp = tcf_chain_dereference(tp->next, chain))
if (!tp->deleting && tp->prio >= prio)
break;
} else {
tp = tcf_chain_dereference(tp->next, chain);
}
if (tp)
tcf_proto_get(tp);
mutex_unlock(&chain->filter_chain_lock);
return tp;
}
/* Function to be used by all clients that want to iterate over all tp's on
* chain. Users of this function must be tolerant to concurrent tp
* insertion/deletion or ensure that no concurrent chain modification is
* possible. Note that all netlink dump callbacks cannot guarantee to provide
* consistent dump because rtnl lock is released each time skb is filled with
* data and sent to user-space.
*/
struct tcf_proto *
tcf_get_next_proto(struct tcf_chain *chain, struct tcf_proto *tp)
{
struct tcf_proto *tp_next = __tcf_get_next_proto(chain, tp);
if (tp)
tcf_proto_put(tp, true, NULL);