Commit db3efdcf authored by Peilin He's avatar Peilin He Committed by David S. Miller
Browse files

net/ipv4: add tracepoint for icmp_send 



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/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

Signed-off-by: default avatarPeilin He <he.peilin@zte.com.cn>
Signed-off-by: default avatarxu xin <xu.xin16@zte.com.cn>
Reviewed-by: default avatarYunkai 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>
Reviewed-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9f481cea

include/trace/events/icmp.h

0 → 100644
+67 −0
Original line number Diff line number Diff line 
/* 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(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)

		),



		TP_fast_assign(

			struct iphdr *iph = ip_hdr(skb);

			struct udphdr *uh = udp_hdr(skb);

			int proto_4 = iph->protocol;

			__be32 *p32;



			__entry->skbaddr = skb;

			__entry->type = type;

			__entry->code = code;



			if (proto_4 != IPPROTO_UDP || (u8 *)uh < skb->head ||

				(u8 *)uh + sizeof(struct udphdr)

				> skb_tail_pointer(skb)) {

				__entry->sport = 0;

				__entry->dport = 0;

				__entry->ulen = 0;

			} else {

				__entry->sport = ntohs(uh->source);

				__entry->dport = ntohs(uh->dest);

				__entry->ulen = ntohs(uh->len);

			}



			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>

net/ipv4/icmp.c

+4 −0
Original line number Diff line number Diff line
@@ -93,6 +93,8 @@ 
#include <net/ip_fib.h>

#include <net/l3mdev.h>

#include <net/addrconf.h>

#define CREATE_TRACE_POINTS

#include <trace/events/icmp.h>



/*

 *	Build xmit assembly blocks
@@ -770,6 +772,8 @@ void __icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info, 
	if (!fl4.saddr)

		fl4.saddr = htonl(INADDR_DUMMY);



	trace_icmp_send(skb_in, type, code);



	icmp_push_reply(sk, &icmp_param, &fl4, &ipc, &rt);

ende:

	ip_rt_put(rt);