This patch adds a minimalistic hook infrastructure in netif_receive_core() that
allows you to attach one hook function at a time. In case that is already in
use, you will hit -EBUSY. The first client of this is sch_ingress that has been
ported on top of it. The abstraction is lightweight to avoid performance
concerns, and it is ruled by a global static key.
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
include/linux/netdevice.h | 13 ++++++++
net/Kconfig | 3 ++
net/core/dev.c | 79 +++++++++++++++++++++------------------------
net/sched/Kconfig | 1 +
net/sched/sch_ingress.c | 38 ++++++++++++++++++++--
5 files changed, 89 insertions(+), 45 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 1899c74..18e1500 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -770,6 +770,15 @@ struct netdev_phys_item_id {
typedef u16 (*select_queue_fallback_t)(struct net_device *dev,
struct sk_buff *skb);
+/* This allows you to register and to unregister a function the hook for
+ * ingress filtering.
+ */
+typedef struct sk_buff *ingress_hook_func_t(struct sk_buff *skb);
+
+int dev_ingress_hook_register(struct net_device *dev,
+ ingress_hook_func_t *hookfn);
+void dev_ingress_hook_unregister(struct net_device *dev);
+
/*
* This structure defines the management hooks for network devices.
* The following hooks can be defined; unless noted otherwise, they are
@@ -1655,7 +1664,11 @@ struct net_device {
rx_handler_func_t __rcu *rx_handler;
void __rcu *rx_handler_data;
+#ifdef CONFIG_NET_INGRESS_HOOK
+ ingress_hook_func_t __rcu *ingress_hook;
+#endif
struct netdev_queue __rcu *ingress_queue;
+
unsigned char broadcast[MAX_ADDR_LEN];
#ifdef CONFIG_RFS_ACCEL
struct cpu_rmap *rx_cpu_rmap;
diff --git a/net/Kconfig b/net/Kconfig
index 44dd578..f0e2f3f 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -230,6 +230,9 @@ source "net/mpls/Kconfig"
source "net/hsr/Kconfig"
source "net/switchdev/Kconfig"
+config NET_INGRESS_HOOK
+ bool
+
config RPS
bool
depends on SMP && SYSFS
diff --git a/net/core/dev.c b/net/core/dev.c
index 862875e..126d0b1 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1630,20 +1630,41 @@ int call_netdevice_notifiers(unsigned long val, struct net_device *dev)
}
EXPORT_SYMBOL(call_netdevice_notifiers);
-#ifdef CONFIG_NET_CLS_ACT
+#ifdef CONFIG_NET_INGRESS_HOOK
static struct static_key ingress_needed __read_mostly;
-void net_inc_ingress_queue(void)
+static DEFINE_MUTEX(ingress_hook_mutex);
+
+int dev_ingress_hook_register(struct net_device *dev,
+ ingress_hook_func_t *hookfn)
{
+ int ret = 0;
+
+ mutex_lock(&ingress_hook_mutex);
+ if (dev->ingress_hook != NULL) {
+ ret = -EBUSY;
+ goto err1;
+ }
+ rcu_assign_pointer(dev->ingress_hook, hookfn);
+ mutex_unlock(&ingress_hook_mutex);
+
static_key_slow_inc(&ingress_needed);
+ return 0;
+err1:
+ mutex_unlock(&ingress_hook_mutex);
+ return ret;
}
-EXPORT_SYMBOL_GPL(net_inc_ingress_queue);
+EXPORT_SYMBOL_GPL(dev_ingress_hook_register);
-void net_dec_ingress_queue(void)
+void dev_ingress_hook_unregister(struct net_device *dev)
{
+ mutex_lock(&ingress_hook_mutex);
+ rcu_assign_pointer(dev->ingress_hook, NULL);
+ mutex_unlock(&ingress_hook_mutex);
static_key_slow_dec(&ingress_needed);
+ synchronize_rcu();
}
-EXPORT_SYMBOL_GPL(net_dec_ingress_queue);
+EXPORT_SYMBOL_GPL(dev_ingress_hook_unregister);
#endif
static struct static_key netstamp_needed __read_mostly;
@@ -3520,38 +3541,15 @@ int (*br_fdb_test_addr_hook)(struct net_device *dev,
EXPORT_SYMBOL_GPL(br_fdb_test_addr_hook);
#endif
-#ifdef CONFIG_NET_CLS_ACT
-/* TODO: Maybe we should just force sch_ingress to be compiled in
- * when CONFIG_NET_CLS_ACT is? otherwise some useless instructions
- * a compare and 2 stores extra right now if we dont have it on
- * but have CONFIG_NET_CLS_ACT
- * NOTE: This doesn't stop any functionality; if you dont have
- * the ingress scheduler, you just can't add policies on ingress.
- *
- */
-static int ing_filter(struct sk_buff *skb, struct netdev_queue *rxq)
-{
- int result = TC_ACT_OK;
- struct Qdisc *q;
-
- skb->tc_verd = SET_TC_AT(skb->tc_verd, AT_INGRESS);
-
- q = rcu_dereference(rxq->qdisc);
- if (q != &noop_qdisc) {
- if (likely(!test_bit(__QDISC_STATE_DEACTIVATED, &q->state)))
- result = qdisc_enqueue_root(skb, q);
- }
-
- return result;
-}
-
+#ifdef CONFIG_NET_INGRESS_HOOK
static inline struct sk_buff *handle_ing(struct sk_buff *skb,
struct packet_type **pt_prev,
int *ret, struct net_device *orig_dev)
{
- struct netdev_queue *rxq = rcu_dereference(skb->dev->ingress_queue);
+ ingress_hook_func_t *ingress_hook;
- if (!rxq || rcu_access_pointer(rxq->qdisc) == &noop_qdisc)
+ ingress_hook = rcu_dereference(skb->dev->ingress_hook);
+ if (ingress_hook == NULL)
return skb;
if (*pt_prev) {
@@ -3559,14 +3557,7 @@ static inline struct sk_buff *handle_ing(struct sk_buff *skb,
*pt_prev = NULL;
}
- switch (ing_filter(skb, rxq)) {
- case TC_ACT_SHOT:
- case TC_ACT_STOLEN:
- kfree_skb(skb);
- return NULL;
- }
-
- return skb;
+ return ingress_hook(skb);
}
#endif
@@ -3700,13 +3691,14 @@ another_round:
}
skip_taps:
-#ifdef CONFIG_NET_CLS_ACT
+#ifdef CONFIG_NET_INGRESS_HOOK
if (static_key_false(&ingress_needed)) {
skb = handle_ing(skb, &pt_prev, &ret, orig_dev);
if (!skb)
goto unlock;
}
-
+#endif
+#ifdef CONFIG_NET_CLS_ACT
skb->tc_verd = 0;
ncls:
#endif
@@ -6846,6 +6838,9 @@ struct net_device *alloc_netdev_mqs(int sizeof_priv, const char *name,
if (netif_alloc_netdev_queues(dev))
goto free_all;
+#ifdef CONFIG_NET_INGRESS_HOOK
+ RCU_INIT_POINTER(dev->ingress_hook, NULL);
+#endif
#ifdef CONFIG_SYSFS
dev->num_rx_queues = rxqs;
dev->real_num_rx_queues = rxqs;
diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index 2274e72..3cef39e 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -312,6 +312,7 @@ config NET_SCH_PIE
config NET_SCH_INGRESS
tristate "Ingress Qdisc"
depends on NET_CLS_ACT
+ select NET_INGRESS_HOOK
---help---
Say Y here if you want to use classifiers for incoming packets.
If unsure, say Y.
diff --git a/net/sched/sch_ingress.c b/net/sched/sch_ingress.c
index a89cc32..38ddef7 100644
--- a/net/sched/sch_ingress.c
+++ b/net/sched/sch_ingress.c
@@ -88,12 +88,44 @@ static int ingress_enqueue(struct sk_buff *skb, struct Qdisc *sch)
/* ------------------------------------------------------------- */
+static int ingress_filter(struct sk_buff *skb, struct netdev_queue *rxq)
+{
+ int result = TC_ACT_OK;
+ struct Qdisc *q;
+
+ skb->tc_verd = SET_TC_AT(skb->tc_verd, AT_INGRESS);
+
+ q = rcu_dereference(rxq->qdisc);
+ if (q != &noop_qdisc) {
+ if (likely(!test_bit(__QDISC_STATE_DEACTIVATED, &q->state)))
+ result = qdisc_enqueue_root(skb, q);
+ }
+
+ return result;
+}
+
+static struct sk_buff *qdisc_ingress_hook(struct sk_buff *skb)
+{
+ struct netdev_queue *rxq = rcu_dereference(skb->dev->ingress_queue);
+
+ if (!rxq || rcu_access_pointer(rxq->qdisc) == &noop_qdisc)
+ return skb;
+
+ switch (ingress_filter(skb, rxq)) {
+ case TC_ACT_SHOT:
+ case TC_ACT_STOLEN:
+ kfree_skb(skb);
+ return 0;
+ }
+
+ return skb;
+}
+
static int ingress_init(struct Qdisc *sch, struct nlattr *opt)
{
- net_inc_ingress_queue();
sch->flags |= TCQ_F_CPUSTATS;
- return 0;
+ return dev_ingress_hook_register(qdisc_dev(sch), qdisc_ingress_hook);
}
static void ingress_destroy(struct Qdisc *sch)
@@ -101,7 +133,7 @@ static void ingress_destroy(struct Qdisc *sch)
struct ingress_qdisc_data *p = qdisc_priv(sch);
tcf_destroy_chain(&p->filter_list);
- net_dec_ingress_queue();
+ dev_ingress_hook_unregister(qdisc_dev(sch));
}
static int ingress_dump(struct Qdisc *sch, struct sk_buff *skb)
--
1.7.10.4
--
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