[PATCH v2] net/ipv4: add tracepoint for icmp_send

[PATCH v2] net/ipv4: add tracepoint for icmp_send

[xu.xin16]

From: Peilin He<he.peilin@zte.com.cn>

Introduce a tracepoint for icmp_send, which can help users to get more
detail information conveniently when icmp abnormal events happen.

1. Giving an usecase example:
=============================
When an application experiences packet loss due to an unreachable UDP
destination port, the kernel will send an exception message through the
icmp_send function. By adding a trace point for icmp_send, developers or
system administrators can obtain detailed information about the UDP
packet loss, including the type, code, source address, destination address,
source port, and destination port. This facilitates the trouble-shooting
of UDP packet loss issues especially for those network-service
applications.

2. Operation Instructions:
==========================
Switch to the tracing directory.
        cd /sys/kernel/debug/tracing
Filter for destination port unreachable.
        echo "type==3 && code==3" > events/icmp/icmp_send/filter
Enable trace event.
        echo 1 > events/icmp/icmp_send/enable

3. Result View:
================
 udp_client_erro-11370   [002] ...s.12   124.728002:
 icmp_send: icmp_send: type=3, code=3.
 From 127.0.0.1:41895 to 127.0.0.1:6666 ulen=23
 skbaddr=00000000589b167a

v1->v2:
Some fixes according to
https://lore.kernel.org/all/CANn89iL-y9e_VFpdw=sZtRnKRu_tnUwqHuFQTJvJsv-nz1xPDw@mail.gmail.com/
	1. adjust the trace_icmp_send() to more protocols than UDP.
	2. move the calling of trace_icmp_send after sanity checks
	   in __icmp_send().

Signed-off-by: Peilin He<he.peilin@zte.com.cn>
Reviewed-by: xu xin <xu.xin16@zte.com.cn>
Reviewed-by: Yunkai Zhang <zhang.yunkai@zte.com.cn>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: Liu Chun <liu.chun2@zte.com.cn>
Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn>
---
 include/trace/events/icmp.h | 64 +++++++++++++++++++++++++++++++++++++++++++++
 net/ipv4/icmp.c             |  4 +++
 2 files changed, 68 insertions(+)
 create mode 100644 include/trace/events/icmp.h

diff --git a/include/trace/events/icmp.h b/include/trace/events/icmp.h
new file mode 100644
index 000000000000..c3dc337be7bc
--- /dev/null
+++ b/include/trace/events/icmp.h
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM icmp
+
+#if !defined(_TRACE_ICMP_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_ICMP_H
+
+#include <linux/icmp.h>
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(icmp_send,
+
+		TP_PROTO(const struct sk_buff *skb, int type, int code),
+
+		TP_ARGS(skb, type, code),
+
+		TP_STRUCT__entry(
+			__field(__u16, sport)
+			__field(__u16, dport)
+			__field(int, type)
+			__field(int, code)
+			__array(__u8, saddr, 4)
+			__array(__u8, daddr, 4)
+                	__field(const void *, skbaddr)
+			__field(unsigned short, ulen)
+		),
+
+		TP_fast_assign(
+			struct iphdr *iph = ip_hdr(skb);
+			int proto_4 = iph->protocol;
+			__be32 *p32;
+
+			__entry->skbaddr = skb;
+			__entry->type = type;
+			__entry->code = code;
+
+			if (proto_4 == IPPROTO_UDP) {
+				struct udphdr *uh = udp_hdr(skb);
+				__entry->sport = ntohs(uh->source);
+				__entry->dport = ntohs(uh->dest);
+				__entry->ulen = ntohs(uh->len);
+			} else {
+				__entry->sport = 0;
+				__entry->dport = 0;
+				__entry->ulen = 0;
+			}
+
+			p32 = (__be32 *) __entry->saddr;
+			*p32 = iph->saddr;
+
+			p32 = (__be32 *) __entry->daddr;
+			*p32 = iph->daddr;
+		),
+
+		TP_printk("icmp_send: type=%d, code=%d. From %pI4:%u to %pI4:%u ulen=%d skbaddr=%p",
+			__entry->type, __entry->code,
+			__entry->saddr, __entry->sport, __entry->daddr,
+			__entry->dport, __entry->ulen, __entry->skbaddr)
+);
+
+#endif /* _TRACE_ICMP_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
\ No newline at end of file
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index e63a3bf99617..21fb41257fe9 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -92,6 +92,8 @@
 #include <net/inet_common.h>
 #include <net/ip_fib.h>
 #include <net/l3mdev.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/icmp.h>

 /*
  *	Build xmit assembly blocks
@@ -672,6 +674,8 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info,
 		}
 	}

+	trace_icmp_send(skb_in, type, code);
+
 	/* Needed by both icmp_global_allow and icmp_xmit_lock */
 	local_bh_disable();

-- 
2.15.2

Re: [PATCH v2] net/ipv4: add tracepoint for icmp_send

[Steven Rostedt]

On Tue, 19 Mar 2024 20:13:52 +0800 (CST)
<xu.xin16@zte.com.cn> wrote:

> From: Peilin He<he.peilin@zte.com.cn>
> 
> Introduce a tracepoint for icmp_send, which can help users to get more
> detail information conveniently when icmp abnormal events happen.
> 
> 1. Giving an usecase example:
> =============================
> When an application experiences packet loss due to an unreachable UDP
> destination port, the kernel will send an exception message through the
> icmp_send function. By adding a trace point for icmp_send, developers or
> system administrators can obtain detailed information about the UDP
> packet loss, including the type, code, source address, destination address,
> source port, and destination port. This facilitates the trouble-shooting
> of UDP packet loss issues especially for those network-service
> applications.
> 
> 2. Operation Instructions:
> ==========================
> Switch to the tracing directory.
>         cd /sys/kernel/debug/tracing

FYI, that directory is obsolete. Please always reference /sys/kernel/tracing.

> Filter for destination port unreachable.
>         echo "type==3 && code==3" > events/icmp/icmp_send/filter
> Enable trace event.
>         echo 1 > events/icmp/icmp_send/enable
> 
> 3. Result View:
> ================
>  udp_client_erro-11370   [002] ...s.12   124.728002:
>  icmp_send: icmp_send: type=3, code=3.
>  From 127.0.0.1:41895 to 127.0.0.1:6666 ulen=23
>  skbaddr=00000000589b167a
> 
> v1->v2:
> Some fixes according to
> https://lore.kernel.org/all/CANn89iL-y9e_VFpdw=sZtRnKRu_tnUwqHuFQTJvJsv-nz1xPDw@mail.gmail.com/
> 	1. adjust the trace_icmp_send() to more protocols than UDP.
> 	2. move the calling of trace_icmp_send after sanity checks
> 	   in __icmp_send().
> 
> Signed-off-by: Peilin He<he.peilin@zte.com.cn>
> Reviewed-by: xu xin <xu.xin16@zte.com.cn>
> Reviewed-by: Yunkai Zhang <zhang.yunkai@zte.com.cn>
> Cc: Yang Yang <yang.yang29@zte.com.cn>
> Cc: Liu Chun <liu.chun2@zte.com.cn>
> Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn>
> ---
>  include/trace/events/icmp.h | 64 +++++++++++++++++++++++++++++++++++++++++++++
>  net/ipv4/icmp.c             |  4 +++
>  2 files changed, 68 insertions(+)
>  create mode 100644 include/trace/events/icmp.h
> 
> diff --git a/include/trace/events/icmp.h b/include/trace/events/icmp.h
> new file mode 100644
> index 000000000000..c3dc337be7bc
> --- /dev/null
> +++ b/include/trace/events/icmp.h
> @@ -0,0 +1,64 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM icmp
> +
> +#if !defined(_TRACE_ICMP_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_ICMP_H
> +
> +#include <linux/icmp.h>
> +#include <linux/tracepoint.h>
> +
> +TRACE_EVENT(icmp_send,
> +
> +		TP_PROTO(const struct sk_buff *skb, int type, int code),
> +
> +		TP_ARGS(skb, type, code),
> +
> +		TP_STRUCT__entry(
> +			__field(__u16, sport)
> +			__field(__u16, dport)
> +			__field(int, type)
> +			__field(int, code)
> +			__array(__u8, saddr, 4)
> +			__array(__u8, daddr, 4)
> +                	__field(const void *, skbaddr)
> +			__field(unsigned short, ulen)

Note, to prevent holes, I usually suggest pointers and longs go first,
followed by ints, and then end with char.

                	__field(const void *, skbaddr)
			__field(int, type)
			__field(int, code)
			__array(__u8, saddr, 4)
			__array(__u8, daddr, 4)
			__field(__u16, sport)
			__field(__u16, dport)
			__field(unsigned short, ulen)

-- Steve


> +		),
> +
> +		TP_fast_assign(
> +			struct iphdr *iph = ip_hdr(skb);
> +			int proto_4 = iph->protocol;
> +			__be32 *p32;
> +
> +			__entry->skbaddr = skb;
> +			__entry->type = type;
> +			__entry->code = code;
> +
> +			if (proto_4 == IPPROTO_UDP) {
> +				struct udphdr *uh = udp_hdr(skb);
> +				__entry->sport = ntohs(uh->source);
> +				__entry->dport = ntohs(uh->dest);
> +				__entry->ulen = ntohs(uh->len);
> +			} else {
> +				__entry->sport = 0;
> +				__entry->dport = 0;
> +				__entry->ulen = 0;
> +			}
> +
> +			p32 = (__be32 *) __entry->saddr;
> +			*p32 = iph->saddr;
> +
> +			p32 = (__be32 *) __entry->daddr;
> +			*p32 = iph->daddr;
> +		),
> +
> +		TP_printk("icmp_send: type=%d, code=%d. From %pI4:%u to %pI4:%u ulen=%d skbaddr=%p",
> +			__entry->type, __entry->code,
> +			__entry->saddr, __entry->sport, __entry->daddr,
> +			__entry->dport, __entry->ulen, __entry->skbaddr)
> +);
> +
> +#endif /* _TRACE_ICMP_H */
> +
> +/* This part must be outside protection */
> +#include <trace/define_trace.h>
> \ No newline at end of file
> diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
> index e63a3bf99617..21fb41257fe9 100644
> --- a/net/ipv4/icmp.c
> +++ b/net/ipv4/icmp.c
> @@ -92,6 +92,8 @@
>  #include <net/inet_common.h>
>  #include <net/ip_fib.h>
>  #include <net/l3mdev.h>
> +#define CREATE_TRACE_POINTS
> +#include <trace/events/icmp.h>
> 
>  /*
>   *	Build xmit assembly blocks
> @@ -672,6 +674,8 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info,
>  		}
>  	}
> 
> +	trace_icmp_send(skb_in, type, code);
> +
>  	/* Needed by both icmp_global_allow and icmp_xmit_lock */
>  	local_bh_disable();
> 

Re: Re: [PATCH v2] net/ipv4: add tracepoint for icmp_send

[He Peilin]

> > From: Peilin He<he.peilin@zte.com.cn>
> > 
> > Introduce a tracepoint for icmp_send, which can help users to get more
> > detail information conveniently when icmp abnormal events happen.
> > 
> > 1. Giving an usecase example:
> > =============================
> > When an application experiences packet loss due to an unreachable UDP
> > destination port, the kernel will send an exception message through the
> > icmp_send function. By adding a trace point for icmp_send, developers or
> > system administrators can obtain detailed information about the UDP
> > packet loss, including the type, code, source address, destination address,
> > source port, and destination port. This facilitates the trouble-shooting
> > of UDP packet loss issues especially for those network-service
> > applications.
> > 
> > 2. Operation Instructions:
> > ==========================
> > Switch to the tracing directory.
> >         cd /sys/kernel/debug/tracing
> 
> FYI, that directory is obsolete. Please always reference /sys/kernel/tracing.
OK. 
> > Filter for destination port unreachable.
> >         echo "type==3 && code==3" > events/icmp/icmp_send/filter
> > Enable trace event.
> >         echo 1 > events/icmp/icmp_send/enable
> > 
> > 3. Result View:
> > ================
> >  udp_client_erro-11370   [002] ...s.12   124.728002:
> >  icmp_send: icmp_send: type=3, code=3.
> >  From 127.0.0.1:41895 to 127.0.0.1:6666 ulen=23
> >  skbaddr=00000000589b167a
> > 
> > v1->v2:
> > Some fixes according to
> > https://lore.kernel.org/all/CANn89iL-y9e_VFpdw=sZtRnKRu_tnUwqHuFQTJvJsv-nz1xPDw@mail.gmail.com/
> > 	1. adjust the trace_icmp_send() to more protocols than UDP.
> > 	2. move the calling of trace_icmp_send after sanity checks
> > 	   in __icmp_send().
> > 
> > Signed-off-by: Peilin He<he.peilin@zte.com.cn>
> > Reviewed-by: xu xin <xu.xin16@zte.com.cn>
> > Reviewed-by: Yunkai Zhang <zhang.yunkai@zte.com.cn>
> > Cc: Yang Yang <yang.yang29@zte.com.cn>
> > Cc: Liu Chun <liu.chun2@zte.com.cn>
> > Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn>
> > ---
> >  include/trace/events/icmp.h | 64 +++++++++++++++++++++++++++++++++++++++++++++
> >  net/ipv4/icmp.c             |  4 +++
> >  2 files changed, 68 insertions(+)
> >  create mode 100644 include/trace/events/icmp.h
> > 
> > diff --git a/include/trace/events/icmp.h b/include/trace/events/icmp.h
> > new file mode 100644
> > index 000000000000..c3dc337be7bc
> > --- /dev/null
> > +++ b/include/trace/events/icmp.h
> > @@ -0,0 +1,64 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#undef TRACE_SYSTEM
> > +#define TRACE_SYSTEM icmp
> > +
> > +#if !defined(_TRACE_ICMP_H) || defined(TRACE_HEADER_MULTI_READ)
> > +#define _TRACE_ICMP_H
> > +
> > +#include <linux/icmp.h>
> > +#include <linux/tracepoint.h>
> > +
> > +TRACE_EVENT(icmp_send,
> > +
> > +		TP_PROTO(const struct sk_buff *skb, int type, int code),
> > +
> > +		TP_ARGS(skb, type, code),
> > +
> > +		TP_STRUCT__entry(
> > +			__field(__u16, sport)
> > +			__field(__u16, dport)
> > +			__field(int, type)
> > +			__field(int, code)
> > +			__array(__u8, saddr, 4)
> > +			__array(__u8, daddr, 4)
> > +                	__field(const void *, skbaddr)
> > +			__field(unsigned short, ulen)
> 
> Note, to prevent holes, I usually suggest pointers and longs go first,
> followed by ints, and then end with char.
> 
>                 	__field(const void *, skbaddr)
> 			__field(int, type)
> 			__field(int, code)
> 			__array(__u8, saddr, 4)
> 			__array(__u8, daddr, 4)
> 			__field(__u16, sport)
> 			__field(__u16, dport)
> 			__field(unsigned short, ulen)
> 
> -- Steve
Thank you very much for your suggestion. We will rearrange the parameters in TP_STRUCT_entry, prioritizing pointers and longs, followed by ints, and ending with char. This will be reflected in Patch v3.
> 
> 
> > +		),
> > +
> > +		TP_fast_assign(
> > +			struct iphdr *iph = ip_hdr(skb);
> > +			int proto_4 = iph->protocol;
> > +			__be32 *p32;
> > +
> > +			__entry->skbaddr = skb;
> > +			__entry->type = type;
> > +			__entry->code = code;
> > +
> > +			if (proto_4 == IPPROTO_UDP) {
> > +				struct udphdr *uh = udp_hdr(skb);
> > +				__entry->sport = ntohs(uh->source);
> > +				__entry->dport = ntohs(uh->dest);
> > +				__entry->ulen = ntohs(uh->len);
> > +			} else {
> > +				__entry->sport = 0;
> > +				__entry->dport = 0;
> > +				__entry->ulen = 0;
> > +			}
> > +
> > +			p32 = (__be32 *) __entry->saddr;
> > +			*p32 = iph->saddr;
> > +
> > +			p32 = (__be32 *) __entry->daddr;
> > +			*p32 = iph->daddr;
> > +		),
> > +
> > +		TP_printk("icmp_send: type=%d, code=%d. From %pI4:%u to %pI4:%u ulen=%d skbaddr=%p",
> > +			__entry->type, __entry->code,
> > +			__entry->saddr, __entry->sport, __entry->daddr,
> > +			__entry->dport, __entry->ulen, __entry->skbaddr)
> > +);
> > +
> > +#endif /* _TRACE_ICMP_H */
> > +
> > +/* This part must be outside protection */
> > +#include <trace/define_trace.h>
> > \ No newline at end of file
> > diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
> > index e63a3bf99617..21fb41257fe9 100644
> > --- a/net/ipv4/icmp.c
> > +++ b/net/ipv4/icmp.c
> > @@ -92,6 +92,8 @@
> >  #include <net/inet_common.h>
> >  #include <net/ip_fib.h>
> >  #include <net/l3mdev.h>
> > +#define CREATE_TRACE_POINTS
> > +#include <trace/events/icmp.h>
> > 
> >  /*
> >   *	Build xmit assembly blocks
> > @@ -672,6 +674,8 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info,
> >  		}
> >  	}
> > 
> > +	trace_icmp_send(skb_in, type, code);
> > +
> >  	/* Needed by both icmp_global_allow and icmp_xmit_lock */
> >  	local_bh_disable();
> >