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net/ipv4: add tracepoint for icmp_send

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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: Peilin He <he.peilin@zte.com.cn>
Signed-off-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>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Peilin He 2024-05-07 15:41:03 +08:00 committed by David S. Miller
parent 9f481cea15
commit db3efdcf70
2 changed files with 71 additions and 0 deletions
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67
include/trace/events/icmp.h Normal file
View File

@ -0,0 +1,67 @@
/* 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>

4
net/ipv4/icmp.c
View File

@ -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);