[PATCH net-next 0/3] net: icmp: add skb drop reasons to icmp

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* [PATCH net-next 0/3] net: icmp: add skb drop reasons to icmp
@ 2022-03-14 11:32 menglong8.dong
  2022-03-14 11:32 ` [PATCH net-next 1/3] net: sock: introduce sock_queue_rcv_skb_reason() menglong8.dong
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: menglong8.dong @ 2022-03-14 11:32 UTC (permalink / raw)
  To: dsahern, kuba
  Cc: davem, rostedt, mingo, yoshfuji, imagedong, edumazet, kafai,
	talalahmad, keescook, alobakin, dongli.zhang, pabeni, maze,
	aahringo, weiwan, yangbo.lu, fw, tglx, rpalethorpe, linux-kernel,
	netdev

From: Menglong Dong <imagedong@tencent.com>

In the commit c504e5c2f964 ("net: skb: introduce kfree_skb_reason()"),
we added the support of reporting the reasons of skb drops to kfree_skb
tracepoint. And in this series patches, reasons for skb drops are added
to ICMP protocol.

In order to report the reasons of skb drops in 'sock_queue_rcv_skb()',
the function 'sock_queue_rcv_skb_reason()' is introduced in the 1th
patch, which is used in the 2th patch.

In the 2th patch, we add skb drop reasons to ping_queue_rcv_skb().

In the 3th patch, we make ICMP message handler functions return drop
reasons, which means we change the return type of 'handler()' in
'struct icmp_control' from 'bool' to 'enum skb_drop_reason'. This
changed its original intention, as 'false' means failure, but
'SKB_NOT_DROPPED_YET', which is 0, means success now. Therefore, we
have to change all usages of these handler. Following "handler" functions
are involved:

icmp_unreach()
icmp_redirect()
icmp_echo()
icmp_timestamp()
icmp_discard()

And following drop reasons are added(what they mean can be see
in the document for them):

SKB_DROP_REASON_ICMP_CSUM
SKB_DROP_REASON_ICMP_TYPE
SKB_DROP_REASON_ICMP_BROADCAST

Menglong Dong (3):
  net: sock: introduce sock_queue_rcv_skb_reason()
  net: icmp: add skb drop reasons to ping_queue_rcv_skb()
  net: icmp: add reasons of the skb drops to icmp protocol

 include/linux/skbuff.h     |  5 +++
 include/net/ping.h         |  2 +-
 include/net/sock.h         |  9 ++++-
 include/trace/events/skb.h |  3 ++
 net/core/sock.c            | 30 ++++++++++++---
 net/ipv4/icmp.c            | 75 ++++++++++++++++++++++----------------
 net/ipv4/ping.c            | 21 ++++++-----
 net/ipv6/icmp.c            | 24 +++++++-----
 8 files changed, 112 insertions(+), 57 deletions(-)

-- 
2.35.1

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH net-next 1/3] net: sock: introduce sock_queue_rcv_skb_reason()
  2022-03-14 11:32 [PATCH net-next 0/3] net: icmp: add skb drop reasons to icmp menglong8.dong
@ 2022-03-14 11:32 ` menglong8.dong
  2022-03-14 11:32 ` [PATCH net-next 2/3] net: icmp: add skb drop reasons to ping_queue_rcv_skb() menglong8.dong
  2022-03-14 11:32 ` [PATCH net-next 3/3] net: icmp: add reasons of the skb drops to icmp protocol menglong8.dong
  2 siblings, 0 replies; 6+ messages in thread
From: menglong8.dong @ 2022-03-14 11:32 UTC (permalink / raw)
  To: dsahern, kuba
  Cc: davem, rostedt, mingo, yoshfuji, imagedong, edumazet, kafai,
	talalahmad, keescook, alobakin, dongli.zhang, pabeni, maze,
	aahringo, weiwan, yangbo.lu, fw, tglx, rpalethorpe, linux-kernel,
	netdev

From: Menglong Dong <imagedong@tencent.com>

In order to report the reasons of skb drops in 'sock_queue_rcv_skb()',
introduce the function 'sock_queue_rcv_skb_reason()'.

As the return value of 'sock_queue_rcv_skb()' is used as the error code,
we can't make it as drop reason and have to pass extra output argument.
'sock_queue_rcv_skb()' is used in many places, so we can't change it
directly.

Introduce the new function 'sock_queue_rcv_skb_reason()' and make
'sock_queue_rcv_skb()' an inline call to it.

Signed-off-by: Menglong Dong <imagedong@tencent.com>
---
 include/net/sock.h |  9 ++++++++-
 net/core/sock.c    | 30 ++++++++++++++++++++++++------
 2 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index c4b91fc19b9c..1a988e605f09 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -2392,7 +2392,14 @@ int __sk_queue_drop_skb(struct sock *sk, struct sk_buff_head *sk_queue,
 			void (*destructor)(struct sock *sk,
 					   struct sk_buff *skb));
 int __sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
-int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
+
+int sock_queue_rcv_skb_reason(struct sock *sk, struct sk_buff *skb,
+			      enum skb_drop_reason *reason);
+
+static inline int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
+{
+	return sock_queue_rcv_skb_reason(sk, skb, NULL);
+}
 
 int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb);
 struct sk_buff *sock_dequeue_err_skb(struct sock *sk);
diff --git a/net/core/sock.c b/net/core/sock.c
index 1180a0cb0110..2cae991f817e 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -503,17 +503,35 @@ int __sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 }
 EXPORT_SYMBOL(__sock_queue_rcv_skb);
 
-int sock_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
+int sock_queue_rcv_skb_reason(struct sock *sk, struct sk_buff *skb,
+			      enum skb_drop_reason *reason)
 {
+	enum skb_drop_reason drop_reason;
 	int err;
 
 	err = sk_filter(sk, skb);
-	if (err)
-		return err;
-
-	return __sock_queue_rcv_skb(sk, skb);
+	if (err) {
+		drop_reason = SKB_DROP_REASON_SOCKET_FILTER;
+		goto out;
+	}
+	err = __sock_queue_rcv_skb(sk, skb);
+	switch (err) {
+	case -ENOMEM:
+		drop_reason = SKB_DROP_REASON_SOCKET_RCVBUFF;
+		break;
+	case -ENOBUFS:
+		drop_reason = SKB_DROP_REASON_PROTO_MEM;
+		break;
+	default:
+		drop_reason = SKB_NOT_DROPPED_YET;
+		break;
+	}
+out:
+	if (reason)
+		*reason = drop_reason;
+	return err;
 }
-EXPORT_SYMBOL(sock_queue_rcv_skb);
+EXPORT_SYMBOL(sock_queue_rcv_skb_reason);
 
 int __sk_receive_skb(struct sock *sk, struct sk_buff *skb,
 		     const int nested, unsigned int trim_cap, bool refcounted)
-- 
2.35.1


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH net-next 2/3] net: icmp: add skb drop reasons to ping_queue_rcv_skb()
  2022-03-14 11:32 [PATCH net-next 0/3] net: icmp: add skb drop reasons to icmp menglong8.dong
  2022-03-14 11:32 ` [PATCH net-next 1/3] net: sock: introduce sock_queue_rcv_skb_reason() menglong8.dong
@ 2022-03-14 11:32 ` menglong8.dong
  2022-03-15 12:49   ` Paolo Abeni
  2022-03-14 11:32 ` [PATCH net-next 3/3] net: icmp: add reasons of the skb drops to icmp protocol menglong8.dong
  2 siblings, 1 reply; 6+ messages in thread
From: menglong8.dong @ 2022-03-14 11:32 UTC (permalink / raw)
  To: dsahern, kuba
  Cc: davem, rostedt, mingo, yoshfuji, imagedong, edumazet, kafai,
	talalahmad, keescook, alobakin, dongli.zhang, pabeni, maze,
	aahringo, weiwan, yangbo.lu, fw, tglx, rpalethorpe, linux-kernel,
	netdev

From: Menglong Dong <imagedong@tencent.com>

In order to get the reasons of skb drops, replace sock_queue_rcv_skb()
used in ping_queue_rcv_skb() with sock_queue_rcv_skb_reason().
Meanwhile, use kfree_skb_reason() instead of kfree_skb().

As we can see in ping_rcv(), 'skb' will be freed if '-1' is returned
by ping_queue_rcv_skb(). In order to get the drop reason of 'skb',
make ping_queue_rcv_skb() return the drop reason.

As ping_queue_rcv_skb() is used as 'ping_prot.backlog_rcv()', we can't
change its return type. (Seems ping_prot.backlog_rcv() is not used?)
Therefore, make it return 'drop_reason * -1' to keep the origin logic.

Signed-off-by: Menglong Dong <imagedong@tencent.com>
---
 net/ipv4/ping.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 3ee947557b88..cd4eb211431a 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -936,12 +936,13 @@ EXPORT_SYMBOL_GPL(ping_recvmsg);
 
 int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
 {
+	enum skb_drop_reason reason;
 	pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
 		 inet_sk(sk), inet_sk(sk)->inet_num, skb);
-	if (sock_queue_rcv_skb(sk, skb) < 0) {
-		kfree_skb(skb);
+	if (sock_queue_rcv_skb_reason(sk, skb, &reason) < 0) {
+		kfree_skb_reason(skb, reason);
 		pr_debug("ping_queue_rcv_skb -> failed\n");
-		return -1;
+		return -reason;
 	}
 	return 0;
 }
-- 
2.35.1


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net-next 2/3] net: icmp: add skb drop reasons to ping_queue_rcv_skb()
  2022-03-14 11:32 ` [PATCH net-next 2/3] net: icmp: add skb drop reasons to ping_queue_rcv_skb() menglong8.dong
@ 2022-03-15 12:49   ` Paolo Abeni
  2022-03-16  1:34     ` Menglong Dong
  0 siblings, 1 reply; 6+ messages in thread
From: Paolo Abeni @ 2022-03-15 12:49 UTC (permalink / raw)
  To: menglong8.dong, dsahern, kuba
  Cc: davem, rostedt, mingo, yoshfuji, imagedong, edumazet, kafai,
	talalahmad, keescook, alobakin, dongli.zhang, maze, aahringo,
	weiwan, yangbo.lu, fw, tglx, rpalethorpe, linux-kernel, netdev

Hello,

On Mon, 2022-03-14 at 19:32 +0800, menglong8.dong@gmail.com wrote:
> From: Menglong Dong <imagedong@tencent.com>
> 
> In order to get the reasons of skb drops, replace sock_queue_rcv_skb()
> used in ping_queue_rcv_skb() with sock_queue_rcv_skb_reason().
> Meanwhile, use kfree_skb_reason() instead of kfree_skb().
> 
> As we can see in ping_rcv(), 'skb' will be freed if '-1' is returned
> by ping_queue_rcv_skb(). In order to get the drop reason of 'skb',
> make ping_queue_rcv_skb() return the drop reason.
> 
> As ping_queue_rcv_skb() is used as 'ping_prot.backlog_rcv()', we can't
> change its return type. (Seems ping_prot.backlog_rcv() is not used?)
> Therefore, make it return 'drop_reason * -1' to keep the origin logic.
> 
> Signed-off-by: Menglong Dong <imagedong@tencent.com>
> ---
>  net/ipv4/ping.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
> index 3ee947557b88..cd4eb211431a 100644
> --- a/net/ipv4/ping.c
> +++ b/net/ipv4/ping.c
> @@ -936,12 +936,13 @@ EXPORT_SYMBOL_GPL(ping_recvmsg);
>  
>  int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
>  {
> +	enum skb_drop_reason reason;

Please insert an empty line between variable declaration and code.

>  	pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
>  		 inet_sk(sk), inet_sk(sk)->inet_num, skb);
> -	if (sock_queue_rcv_skb(sk, skb) < 0) {
> -		kfree_skb(skb);
> +	if (sock_queue_rcv_skb_reason(sk, skb, &reason) < 0) {
> +		kfree_skb_reason(skb, reason);
>  		pr_debug("ping_queue_rcv_skb -> failed\n");
> -		return -1;
> +		return -reason;

This changes the return value for the release callback.  Such callback
has a long and non trivial call chain via sk_backlog_rcv. 

It *should* be safe, but have you considered factoring out an
__ping_queue_rcv_skb() variant returning the full drop reason, use it
in the next patch and build ping_queue_rcv_skb() on top of such helper
to that backlog_rcv() return code will not change?

The above should additionally avoid the IMHO not so nice:

	reason = ping_queue_rcv_skb(sk, skb2) * -1;

in the next patch - it will become:

	reason = __ping_queue_rcv_skb(sk, skb2);

Thanks!

Paolo


^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH net-next 2/3] net: icmp: add skb drop reasons to ping_queue_rcv_skb()
  2022-03-15 12:49   ` Paolo Abeni
@ 2022-03-16  1:34     ` Menglong Dong
  0 siblings, 0 replies; 6+ messages in thread
From: Menglong Dong @ 2022-03-16  1:34 UTC (permalink / raw)
  To: Paolo Abeni
  Cc: David Ahern, Jakub Kicinski, David Miller, Steven Rostedt,
	Ingo Molnar, Hideaki YOSHIFUJI, Menglong Dong, Eric Dumazet,
	Martin Lau, Talal Ahmad, Kees Cook, Alexander Lobakin,
	dongli.zhang, maze, aahringo, Wei Wang, yangbo.lu,
	Florian Westphal, tglx, rpalethorpe, LKML, netdev

On Tue, Mar 15, 2022 at 8:49 PM Paolo Abeni <pabeni@redhat.com> wrote:
>
> Hello,
>
> On Mon, 2022-03-14 at 19:32 +0800, menglong8.dong@gmail.com wrote:
> > From: Menglong Dong <imagedong@tencent.com>
> >
> > In order to get the reasons of skb drops, replace sock_queue_rcv_skb()
> > used in ping_queue_rcv_skb() with sock_queue_rcv_skb_reason().
> > Meanwhile, use kfree_skb_reason() instead of kfree_skb().
> >
> > As we can see in ping_rcv(), 'skb' will be freed if '-1' is returned
> > by ping_queue_rcv_skb(). In order to get the drop reason of 'skb',
> > make ping_queue_rcv_skb() return the drop reason.
> >
> > As ping_queue_rcv_skb() is used as 'ping_prot.backlog_rcv()', we can't
> > change its return type. (Seems ping_prot.backlog_rcv() is not used?)
> > Therefore, make it return 'drop_reason * -1' to keep the origin logic.
> >
> > Signed-off-by: Menglong Dong <imagedong@tencent.com>
> > ---
> >  net/ipv4/ping.c | 7 ++++---
> >  1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
> > index 3ee947557b88..cd4eb211431a 100644
> > --- a/net/ipv4/ping.c
> > +++ b/net/ipv4/ping.c
> > @@ -936,12 +936,13 @@ EXPORT_SYMBOL_GPL(ping_recvmsg);
> >
> >  int ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
> >  {
> > +     enum skb_drop_reason reason;
>
> Please insert an empty line between variable declaration and code.

Ok

>
> >       pr_debug("ping_queue_rcv_skb(sk=%p,sk->num=%d,skb=%p)\n",
> >                inet_sk(sk), inet_sk(sk)->inet_num, skb);
> > -     if (sock_queue_rcv_skb(sk, skb) < 0) {
> > -             kfree_skb(skb);
> > +     if (sock_queue_rcv_skb_reason(sk, skb, &reason) < 0) {
> > +             kfree_skb_reason(skb, reason);
> >               pr_debug("ping_queue_rcv_skb -> failed\n");
> > -             return -1;
> > +             return -reason;
>
> This changes the return value for the release callback.  Such callback
> has a long and non trivial call chain via sk_backlog_rcv.
>
> It *should* be safe, but have you considered factoring out an
> __ping_queue_rcv_skb() variant returning the full drop reason, use it
> in the next patch and build ping_queue_rcv_skb() on top of such helper
> to that backlog_rcv() return code will not change?
>
> The above should additionally avoid the IMHO not so nice:
>
>         reason = ping_queue_rcv_skb(sk, skb2) * -1;
>
> in the next patch - it will become:
>
>         reason = __ping_queue_rcv_skb(sk, skb2);
>

Good idea, thanks!

Menglong Dong

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH net-next 3/3] net: icmp: add reasons of the skb drops to icmp protocol
  2022-03-14 11:32 [PATCH net-next 0/3] net: icmp: add skb drop reasons to icmp menglong8.dong
  2022-03-14 11:32 ` [PATCH net-next 1/3] net: sock: introduce sock_queue_rcv_skb_reason() menglong8.dong
  2022-03-14 11:32 ` [PATCH net-next 2/3] net: icmp: add skb drop reasons to ping_queue_rcv_skb() menglong8.dong
@ 2022-03-14 11:32 ` menglong8.dong
  2 siblings, 0 replies; 6+ messages in thread
From: menglong8.dong @ 2022-03-14 11:32 UTC (permalink / raw)
  To: dsahern, kuba
  Cc: davem, rostedt, mingo, yoshfuji, imagedong, edumazet, kafai,
	talalahmad, keescook, alobakin, dongli.zhang, pabeni, maze,
	aahringo, weiwan, yangbo.lu, fw, tglx, rpalethorpe, linux-kernel,
	netdev

From: Menglong Dong <imagedong@tencent.com>

Replace kfree_skb() used in icmp_rcv() and icmpv6_rcv() with
kfree_skb_reason().

In order to get the reasons of the skb drops after icmp message handle,
we change the return type of 'handler()' in 'struct icmp_control' from
'bool' to 'enum skb_drop_reason'. This may change its original
intention, as 'false' means failure, but 'SKB_NOT_DROPPED_YET' means
success now. Following functions are involved:

icmp_unreach()
icmp_redirect()
icmp_echo()
icmp_timestamp()
icmp_discard()

And following new drop reasons are added:

SKB_DROP_REASON_ICMP_CSUM
SKB_DROP_REASON_ICMP_TYPE
SKB_DROP_REASON_ICMP_BROADCAST

Signed-off-by: Menglong Dong <imagedong@tencent.com>
---
 include/linux/skbuff.h     |  5 +++
 include/net/ping.h         |  2 +-
 include/trace/events/skb.h |  3 ++
 net/ipv4/icmp.c            | 75 ++++++++++++++++++++++----------------
 net/ipv4/ping.c            | 14 ++++---
 net/ipv6/icmp.c            | 24 +++++++-----
 6 files changed, 76 insertions(+), 47 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 26538ceb4b01..18c678b340d3 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -444,6 +444,11 @@ enum skb_drop_reason {
 	SKB_DROP_REASON_TAP_TXFILTER,	/* dropped by tx filter implemented
 					 * at tun/tap, e.g., check_filter()
 					 */
+	SKB_DROP_REASON_ICMP_CSUM,	/* ICMP checksum error */
+	SKB_DROP_REASON_ICMP_TYPE,	/* unknown ICMP type */
+	SKB_DROP_REASON_ICMP_BROADCAST,	/* unacceptable broadcast(multicast)
+					 * ICMP message
+					 */
 	SKB_DROP_REASON_MAX,
 };
 
diff --git a/include/net/ping.h b/include/net/ping.h
index 2fe78874318c..b68fbfdb606f 100644
--- a/include/net/ping.h
+++ b/include/net/ping.h
@@ -76,7 +76,7 @@ int  ping_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
 int  ping_common_sendmsg(int family, struct msghdr *msg, size_t len,
 			 void *user_icmph, size_t icmph_len);
 int  ping_queue_rcv_skb(struct sock *sk, struct sk_buff *skb);
-bool ping_rcv(struct sk_buff *skb);
+enum skb_drop_reason ping_rcv(struct sk_buff *skb);
 
 #ifdef CONFIG_PROC_FS
 void *ping_seq_start(struct seq_file *seq, loff_t *pos, sa_family_t family);
diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h
index e1670e1e4934..70d0dac8e08b 100644
--- a/include/trace/events/skb.h
+++ b/include/trace/events/skb.h
@@ -61,6 +61,9 @@
 	EM(SKB_DROP_REASON_HDR_TRUNC, HDR_TRUNC)		\
 	EM(SKB_DROP_REASON_TAP_FILTER, TAP_FILTER)		\
 	EM(SKB_DROP_REASON_TAP_TXFILTER, TAP_TXFILTER)		\
+	EM(SKB_DROP_REASON_ICMP_CSUM, ICMP_CSUM)		\
+	EM(SKB_DROP_REASON_ICMP_TYPE, ICMP_TYPE)		\
+	EM(SKB_DROP_REASON_ICMP_BROADCAST, ICMP_BROADCAST)	\
 	EMe(SKB_DROP_REASON_MAX, MAX)
 
 #undef EM
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 72a375c7f417..97e53f86b14b 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -186,7 +186,7 @@ EXPORT_SYMBOL(icmp_err_convert);
  */
 
 struct icmp_control {
-	bool (*handler)(struct sk_buff *skb);
+	enum skb_drop_reason (*handler)(struct sk_buff *skb);
 	short   error;		/* This ICMP is classed as an error message */
 };
 
@@ -839,8 +839,9 @@ static bool icmp_tag_validation(int proto)
  *	ICMP_PARAMETERPROB.
  */
 
-static bool icmp_unreach(struct sk_buff *skb)
+static enum skb_drop_reason icmp_unreach(struct sk_buff *skb)
 {
+	enum skb_drop_reason reason = SKB_NOT_DROPPED_YET;
 	const struct iphdr *iph;
 	struct icmphdr *icmph;
 	struct net *net;
@@ -860,8 +861,10 @@ static bool icmp_unreach(struct sk_buff *skb)
 	icmph = icmp_hdr(skb);
 	iph   = (const struct iphdr *)skb->data;
 
-	if (iph->ihl < 5) /* Mangled header, drop. */
+	if (iph->ihl < 5)  { /* Mangled header, drop. */
+		reason = SKB_DROP_REASON_IP_INHDR;
 		goto out_err;
+	}
 
 	switch (icmph->type) {
 	case ICMP_DEST_UNREACH:
@@ -941,10 +944,10 @@ static bool icmp_unreach(struct sk_buff *skb)
 	icmp_socket_deliver(skb, info);
 
 out:
-	return true;
+	return reason;
 out_err:
 	__ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
-	return false;
+	return reason ?: SKB_DROP_REASON_NOT_SPECIFIED;
 }
 
 
@@ -952,20 +955,20 @@ static bool icmp_unreach(struct sk_buff *skb)
  *	Handle ICMP_REDIRECT.
  */
 
-static bool icmp_redirect(struct sk_buff *skb)
+static enum skb_drop_reason icmp_redirect(struct sk_buff *skb)
 {
 	if (skb->len < sizeof(struct iphdr)) {
 		__ICMP_INC_STATS(dev_net(skb->dev), ICMP_MIB_INERRORS);
-		return false;
+		return SKB_DROP_REASON_PKT_TOO_SMALL;
 	}
 
 	if (!pskb_may_pull(skb, sizeof(struct iphdr))) {
 		/* there aught to be a stat */
-		return false;
+		return SKB_DROP_REASON_NOMEM;
 	}
 
 	icmp_socket_deliver(skb, ntohl(icmp_hdr(skb)->un.gateway));
-	return true;
+	return SKB_NOT_DROPPED_YET;
 }
 
 /*
@@ -982,7 +985,7 @@ static bool icmp_redirect(struct sk_buff *skb)
  *	See also WRT handling of options once they are done and working.
  */
 
-static bool icmp_echo(struct sk_buff *skb)
+static enum skb_drop_reason icmp_echo(struct sk_buff *skb)
 {
 	struct icmp_bxm icmp_param;
 	struct net *net;
@@ -990,7 +993,7 @@ static bool icmp_echo(struct sk_buff *skb)
 	net = dev_net(skb_dst(skb)->dev);
 	/* should there be an ICMP stat for ignored echos? */
 	if (net->ipv4.sysctl_icmp_echo_ignore_all)
-		return true;
+		return SKB_NOT_DROPPED_YET;
 
 	icmp_param.data.icmph	   = *icmp_hdr(skb);
 	icmp_param.skb		   = skb;
@@ -1001,10 +1004,10 @@ static bool icmp_echo(struct sk_buff *skb)
 	if (icmp_param.data.icmph.type == ICMP_ECHO)
 		icmp_param.data.icmph.type = ICMP_ECHOREPLY;
 	else if (!icmp_build_probe(skb, &icmp_param.data.icmph))
-		return true;
+		return SKB_NOT_DROPPED_YET;
 
 	icmp_reply(&icmp_param, skb);
-	return true;
+	return SKB_NOT_DROPPED_YET;
 }
 
 /*	Helper for icmp_echo and icmpv6_echo_reply.
@@ -1122,7 +1125,7 @@ EXPORT_SYMBOL_GPL(icmp_build_probe);
  *		  MUST be accurate to a few minutes.
  *		  MUST be updated at least at 15Hz.
  */
-static bool icmp_timestamp(struct sk_buff *skb)
+static enum skb_drop_reason icmp_timestamp(struct sk_buff *skb)
 {
 	struct icmp_bxm icmp_param;
 	/*
@@ -1147,17 +1150,17 @@ static bool icmp_timestamp(struct sk_buff *skb)
 	icmp_param.data_len	   = 0;
 	icmp_param.head_len	   = sizeof(struct icmphdr) + 12;
 	icmp_reply(&icmp_param, skb);
-	return true;
+	return SKB_NOT_DROPPED_YET;
 
 out_err:
 	__ICMP_INC_STATS(dev_net(skb_dst(skb)->dev), ICMP_MIB_INERRORS);
-	return false;
+	return SKB_DROP_REASON_PKT_TOO_SMALL;
 }
 
-static bool icmp_discard(struct sk_buff *skb)
+static enum skb_drop_reason icmp_discard(struct sk_buff *skb)
 {
 	/* pretend it was a success */
-	return true;
+	return SKB_NOT_DROPPED_YET;
 }
 
 /*
@@ -1165,18 +1168,20 @@ static bool icmp_discard(struct sk_buff *skb)
  */
 int icmp_rcv(struct sk_buff *skb)
 {
-	struct icmphdr *icmph;
+	enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
 	struct rtable *rt = skb_rtable(skb);
 	struct net *net = dev_net(rt->dst.dev);
-	bool success;
+	struct icmphdr *icmph;
 
 	if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 		struct sec_path *sp = skb_sec_path(skb);
 		int nh;
 
 		if (!(sp && sp->xvec[sp->len - 1]->props.flags &
-				 XFRM_STATE_ICMP))
+				 XFRM_STATE_ICMP)) {
+			reason = SKB_DROP_REASON_XFRM_POLICY;
 			goto drop;
+		}
 
 		if (!pskb_may_pull(skb, sizeof(*icmph) + sizeof(struct iphdr)))
 			goto drop;
@@ -1184,8 +1189,11 @@ int icmp_rcv(struct sk_buff *skb)
 		nh = skb_network_offset(skb);
 		skb_set_network_header(skb, sizeof(*icmph));
 
-		if (!xfrm4_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
+		if (!xfrm4_policy_check_reverse(NULL, XFRM_POLICY_IN,
+						skb)) {
+			reason = SKB_DROP_REASON_XFRM_POLICY;
 			goto drop;
+		}
 
 		skb_set_network_header(skb, nh);
 	}
@@ -1207,13 +1215,13 @@ int icmp_rcv(struct sk_buff *skb)
 		/* We can't use icmp_pointers[].handler() because it is an array of
 		 * size NR_ICMP_TYPES + 1 (19 elements) and PROBE has code 42.
 		 */
-		success = icmp_echo(skb);
-		goto success_check;
+		reason = icmp_echo(skb);
+		goto reason_check;
 	}
 
 	if (icmph->type == ICMP_EXT_ECHOREPLY) {
-		success = ping_rcv(skb);
-		goto success_check;
+		reason = ping_rcv(skb);
+		goto reason_check;
 	}
 
 	/*
@@ -1222,8 +1230,10 @@ int icmp_rcv(struct sk_buff *skb)
 	 *	RFC 1122: 3.2.2  Unknown ICMP messages types MUST be silently
 	 *		  discarded.
 	 */
-	if (icmph->type > NR_ICMP_TYPES)
+	if (icmph->type > NR_ICMP_TYPES) {
+		reason = SKB_DROP_REASON_ICMP_TYPE;
 		goto error;
+	}
 
 	/*
 	 *	Parse the ICMP message
@@ -1239,27 +1249,30 @@ int icmp_rcv(struct sk_buff *skb)
 		if ((icmph->type == ICMP_ECHO ||
 		     icmph->type == ICMP_TIMESTAMP) &&
 		    net->ipv4.sysctl_icmp_echo_ignore_broadcasts) {
+			reason = SKB_DROP_REASON_ICMP_BROADCAST;
 			goto error;
 		}
 		if (icmph->type != ICMP_ECHO &&
 		    icmph->type != ICMP_TIMESTAMP &&
 		    icmph->type != ICMP_ADDRESS &&
 		    icmph->type != ICMP_ADDRESSREPLY) {
+			reason = SKB_DROP_REASON_ICMP_BROADCAST;
 			goto error;
 		}
 	}
 
-	success = icmp_pointers[icmph->type].handler(skb);
-success_check:
-	if (success)  {
+	reason = icmp_pointers[icmph->type].handler(skb);
+reason_check:
+	if (!reason)  {
 		consume_skb(skb);
 		return NET_RX_SUCCESS;
 	}
 
 drop:
-	kfree_skb(skb);
+	kfree_skb_reason(skb, reason);
 	return NET_RX_DROP;
 csum_error:
+	reason = SKB_DROP_REASON_ICMP_CSUM;
 	__ICMP_INC_STATS(net, ICMP_MIB_CSUMERRORS);
 error:
 	__ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index cd4eb211431a..4442de0093f6 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -953,12 +953,12 @@ EXPORT_SYMBOL_GPL(ping_queue_rcv_skb);
  *	All we need to do is get the socket.
  */
 
-bool ping_rcv(struct sk_buff *skb)
+enum skb_drop_reason ping_rcv(struct sk_buff *skb)
 {
+	enum skb_drop_reason reason = SKB_DROP_REASON_NO_SOCKET;
 	struct sock *sk;
 	struct net *net = dev_net(skb->dev);
 	struct icmphdr *icmph = icmp_hdr(skb);
-	bool rc = false;
 
 	/* We assume the packet has already been checked by icmp_rcv */
 
@@ -973,15 +973,17 @@ bool ping_rcv(struct sk_buff *skb)
 		struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 
 		pr_debug("rcv on socket %p\n", sk);
-		if (skb2 && !ping_queue_rcv_skb(sk, skb2))
-			rc = true;
+		if (skb2)
+			reason = ping_queue_rcv_skb(sk, skb2) * -1;
+		else
+			reason = SKB_DROP_REASON_NOMEM;
 		sock_put(sk);
 	}
 
-	if (!rc)
+	if (reason)
 		pr_debug("no socket, dropping\n");
 
-	return rc;
+	return reason;
 }
 EXPORT_SYMBOL_GPL(ping_rcv);
 
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index e6b978ea0e87..01c8003c9fc9 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -864,21 +864,23 @@ void icmpv6_notify(struct sk_buff *skb, u8 type, u8 code, __be32 info)
 
 static int icmpv6_rcv(struct sk_buff *skb)
 {
+	enum skb_drop_reason reason = SKB_DROP_REASON_NOT_SPECIFIED;
 	struct net *net = dev_net(skb->dev);
 	struct net_device *dev = icmp6_dev(skb);
 	struct inet6_dev *idev = __in6_dev_get(dev);
 	const struct in6_addr *saddr, *daddr;
 	struct icmp6hdr *hdr;
 	u8 type;
-	bool success = false;
 
 	if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 		struct sec_path *sp = skb_sec_path(skb);
 		int nh;
 
 		if (!(sp && sp->xvec[sp->len - 1]->props.flags &
-				 XFRM_STATE_ICMP))
+				 XFRM_STATE_ICMP)) {
+			reason = SKB_DROP_REASON_XFRM_POLICY;
 			goto drop_no_count;
+		}
 
 		if (!pskb_may_pull(skb, sizeof(*hdr) + sizeof(struct ipv6hdr)))
 			goto drop_no_count;
@@ -886,8 +888,11 @@ static int icmpv6_rcv(struct sk_buff *skb)
 		nh = skb_network_offset(skb);
 		skb_set_network_header(skb, sizeof(*hdr));
 
-		if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN, skb))
+		if (!xfrm6_policy_check_reverse(NULL, XFRM_POLICY_IN,
+						skb)) {
+			reason = SKB_DROP_REASON_XFRM_POLICY;
 			goto drop_no_count;
+		}
 
 		skb_set_network_header(skb, nh);
 	}
@@ -924,11 +929,11 @@ static int icmpv6_rcv(struct sk_buff *skb)
 		break;
 
 	case ICMPV6_ECHO_REPLY:
-		success = ping_rcv(skb);
+		reason = ping_rcv(skb);
 		break;
 
 	case ICMPV6_EXT_ECHO_REPLY:
-		success = ping_rcv(skb);
+		reason = ping_rcv(skb);
 		break;
 
 	case ICMPV6_PKT_TOOBIG:
@@ -994,19 +999,20 @@ static int icmpv6_rcv(struct sk_buff *skb)
 	/* until the v6 path can be better sorted assume failure and
 	 * preserve the status quo behaviour for the rest of the paths to here
 	 */
-	if (success)
-		consume_skb(skb);
+	if (reason)
+		kfree_skb_reason(skb, reason);
 	else
-		kfree_skb(skb);
+		consume_skb(skb);
 
 	return 0;
 
 csum_error:
+	reason = SKB_DROP_REASON_ICMP_CSUM;
 	__ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_CSUMERRORS);
 discard_it:
 	__ICMP6_INC_STATS(dev_net(dev), idev, ICMP6_MIB_INERRORS);
 drop_no_count:
-	kfree_skb(skb);
+	kfree_skb_reason(skb, reason);
 	return 0;
 }
 
-- 
2.35.1


^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2022-03-16  1:34 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-03-14 11:32 [PATCH net-next 0/3] net: icmp: add skb drop reasons to icmp menglong8.dong
2022-03-14 11:32 ` [PATCH net-next 1/3] net: sock: introduce sock_queue_rcv_skb_reason() menglong8.dong
2022-03-14 11:32 ` [PATCH net-next 2/3] net: icmp: add skb drop reasons to ping_queue_rcv_skb() menglong8.dong
2022-03-15 12:49   ` Paolo Abeni
2022-03-16  1:34     ` Menglong Dong
2022-03-14 11:32 ` [PATCH net-next 3/3] net: icmp: add reasons of the skb drops to icmp protocol menglong8.dong

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