lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20220104032134.1239096-2-imagedong@tencent.com>
Date:   Tue,  4 Jan 2022 11:21:32 +0800
From:   menglong8.dong@...il.com
To:     rostedt@...dmis.org, kuba@...nel.org, dsahern@...nel.org
Cc:     mingo@...hat.com, davem@...emloft.net, nhorman@...driver.com,
        edumazet@...gle.com, yoshfuji@...ux-ipv6.org,
        jonathan.lemon@...il.com, alobakin@...me, keescook@...omium.org,
        cong.wang@...edance.com, talalahmad@...gle.com, haokexin@...il.com,
        imagedong@...cent.com, atenart@...nel.org, bigeasy@...utronix.de,
        weiwan@...gle.com, arnd@...db.de, pabeni@...hat.com,
        vvs@...tuozzo.com, linux-kernel@...r.kernel.org,
        netdev@...r.kernel.org, mengensun@...cent.com,
        mungerjiang@...cent.com
Subject: [PATCH v3 net-next 1/3] net: skb: introduce kfree_skb_reason()

From: Menglong Dong <imagedong@...cent.com>

Introduce the interface kfree_skb_reason(), which is able to pass
the reason why the skb is dropped to 'kfree_skb' tracepoint.

Add the 'reason' field to 'trace_kfree_skb', therefor user can get
more detail information about abnormal skb with 'drop_monitor' or
eBPF.

Signed-off-by: Menglong Dong <imagedong@...cent.com>
---
v3:
- rename kfree_skb_with_reason() to kfree_skb_reason()
- turn kfree_skb() into a static inline calling kfree_skb_reason()
---
 include/linux/skbuff.h     | 23 ++++++++++++++++++++++-
 include/trace/events/skb.h | 35 ++++++++++++++++++++++++++++-------
 net/core/dev.c             |  3 ++-
 net/core/drop_monitor.c    | 10 +++++++---
 net/core/skbuff.c          | 12 +++++++-----
 5 files changed, 66 insertions(+), 17 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 642acb0d1646..ef0870abc791 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -305,6 +305,17 @@ struct sk_buff_head {
 
 struct sk_buff;
 
+/* The reason of skb drop, which is used in kfree_skb_reason().
+ * en...maybe they should be splited by group?
+ *
+ * Each item here should also be in 'TRACE_SKB_DROP_REASON', which is
+ * used to translate the reason to string.
+ */
+enum skb_drop_reason {
+	SKB_DROP_REASON_NOT_SPECIFIED,
+	SKB_DROP_REASON_MAX,
+};
+
 /* To allow 64K frame to be packed as single skb without frag_list we
  * require 64K/PAGE_SIZE pages plus 1 additional page to allow for
  * buffers which do not start on a page boundary.
@@ -1085,8 +1096,18 @@ static inline bool skb_unref(struct sk_buff *skb)
 	return true;
 }
 
+void kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason);
+
+/**
+ *	kfree_skb - free an sk_buff with 'NOT_SPECIFIED' reason
+ *	@skb: buffer to free
+ */
+static inline void kfree_skb(struct sk_buff *skb)
+{
+	kfree_skb_reason(skb, SKB_DROP_REASON_NOT_SPECIFIED);
+}
+
 void skb_release_head_state(struct sk_buff *skb);
-void kfree_skb(struct sk_buff *skb);
 void kfree_skb_list(struct sk_buff *segs);
 void skb_dump(const char *level, const struct sk_buff *skb, bool full_pkt);
 void skb_tx_error(struct sk_buff *skb);
diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h
index 9e92f22eb086..b5ef652e5a93 100644
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -9,29 +9,50 @@
 #include <linux/netdevice.h>
 #include <linux/tracepoint.h>
 
+#define TRACE_SKB_DROP_REASON					\
+	EM(SKB_DROP_REASON_NOT_SPECIFIED, NOT_SPECIFIED)	\
+	EMe(SKB_DROP_REASON_MAX, MAX)
+
+#undef EM
+#undef EMe
+
+#define EM(a, b)	TRACE_DEFINE_ENUM(a);
+#define EMe(a, b)	TRACE_DEFINE_ENUM(a);
+
+TRACE_SKB_DROP_REASON
+
+#undef EM
+#undef EMe
+#define EM(a, b)	{ a, #b },
+#define EMe(a, b)	{ a, #b }
+
 /*
  * Tracepoint for free an sk_buff:
  */
 TRACE_EVENT(kfree_skb,
 
-	TP_PROTO(struct sk_buff *skb, void *location),
+	TP_PROTO(struct sk_buff *skb, void *location,
+		 enum skb_drop_reason reason),
 
-	TP_ARGS(skb, location),
+	TP_ARGS(skb, location, reason),
 
 	TP_STRUCT__entry(
-		__field(	void *,		skbaddr		)
-		__field(	void *,		location	)
-		__field(	unsigned short,	protocol	)
+		__field(void *,		skbaddr)
+		__field(void *,		location)
+		__field(unsigned short,	protocol)
+		__field(enum skb_drop_reason,	reason)
 	),
 
 	TP_fast_assign(
 		__entry->skbaddr = skb;
 		__entry->location = location;
 		__entry->protocol = ntohs(skb->protocol);
+		__entry->reason = reason;
 	),
 
-	TP_printk("skbaddr=%p protocol=%u location=%p",
-		__entry->skbaddr, __entry->protocol, __entry->location)
+	TP_printk("skbaddr=%p protocol=%u location=%p reason: %s",
+		__entry->skbaddr, __entry->protocol, __entry->location,
+		__print_symbolic(__entry->reason, TRACE_SKB_DROP_REASON))
 );
 
 TRACE_EVENT(consume_skb,
diff --git a/net/core/dev.c b/net/core/dev.c
index 6c8b226b5f2f..70a6aca1dabf 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4899,7 +4899,8 @@ static __latent_entropy void net_tx_action(struct softirq_action *h)
 			if (likely(get_kfree_skb_cb(skb)->reason == SKB_REASON_CONSUMED))
 				trace_consume_skb(skb);
 			else
-				trace_kfree_skb(skb, net_tx_action);
+				trace_kfree_skb(skb, net_tx_action,
+						SKB_DROP_REASON_NOT_SPECIFIED);
 
 			if (skb->fclone != SKB_FCLONE_UNAVAILABLE)
 				__kfree_skb(skb);
diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c
index 3d0ab2eec916..7b288a121a41 100644
--- a/net/core/drop_monitor.c
+++ b/net/core/drop_monitor.c
@@ -110,7 +110,8 @@ static u32 net_dm_queue_len = 1000;
 
 struct net_dm_alert_ops {
 	void (*kfree_skb_probe)(void *ignore, struct sk_buff *skb,
-				void *location);
+				void *location,
+				enum skb_drop_reason reason);
 	void (*napi_poll_probe)(void *ignore, struct napi_struct *napi,
 				int work, int budget);
 	void (*work_item_func)(struct work_struct *work);
@@ -262,7 +263,9 @@ static void trace_drop_common(struct sk_buff *skb, void *location)
 	spin_unlock_irqrestore(&data->lock, flags);
 }
 
-static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb, void *location)
+static void trace_kfree_skb_hit(void *ignore, struct sk_buff *skb,
+				void *location,
+				enum skb_drop_reason reason)
 {
 	trace_drop_common(skb, location);
 }
@@ -490,7 +493,8 @@ static const struct net_dm_alert_ops net_dm_alert_summary_ops = {
 
 static void net_dm_packet_trace_kfree_skb_hit(void *ignore,
 					      struct sk_buff *skb,
-					      void *location)
+					      void *location,
+					      enum skb_drop_reason reason)
 {
 	ktime_t tstamp = ktime_get_real();
 	struct per_cpu_dm_data *data;
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index e514a36bcffc..0118f0afaa4f 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -759,21 +759,23 @@ void __kfree_skb(struct sk_buff *skb)
 EXPORT_SYMBOL(__kfree_skb);
 
 /**
- *	kfree_skb - free an sk_buff
+ *	kfree_skb_reason - free an sk_buff with special reason
  *	@skb: buffer to free
+ *	@reason: reason why this skb is dropped
  *
  *	Drop a reference to the buffer and free it if the usage count has
- *	hit zero.
+ *	hit zero. Meanwhile, pass the drop reason to 'kfree_skb'
+ *	tracepoint.
  */
-void kfree_skb(struct sk_buff *skb)
+void kfree_skb_reason(struct sk_buff *skb, enum skb_drop_reason reason)
 {
 	if (!skb_unref(skb))
 		return;
 
-	trace_kfree_skb(skb, __builtin_return_address(0));
+	trace_kfree_skb(skb, __builtin_return_address(0), reason);
 	__kfree_skb(skb);
 }
-EXPORT_SYMBOL(kfree_skb);
+EXPORT_SYMBOL(kfree_skb_reason);
 
 void kfree_skb_list(struct sk_buff *segs)
 {
-- 
2.30.2

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ