Re: [PATCH v3 resend] net/ipv4: add tracepoint for icmp_send
From: Jason Xing <hidden>
Date: 2024-03-21 03:27:33
Also in:
linux-trace-kernel, lkml
On Thu, Mar 21, 2024 at 11:09 AM [off-list ref] wrote:
From: he peilin <redacted>
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
Changelog
---------
v2->v3:
Some fixes according to
https://lore.kernel.org/all/20240319102549.7f7f6f53@gandalf.local.home/ (local)
1. Change the tracking directory to/sys/kernel/tracking.
2. Adjust the layout of the TP-STRUCT_entry parameter structure.
v1->v2:
Some fixes according to
https://lore.kernel.org/all/CANn89iL-y9e_VFpdw=sZtRnKRu_tnUwqHuFQTJvJsv-nz1xPDw@mail.gmail.com/ (local)
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<redacted>
Reviewed-by: xu xin <xu.xin16@zte.com.cn>
Reviewed-by: Yunkai Zhang <redacted>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Cc: Liu Chun <redacted>
Cc: Xuexin Jiang <redacted>I think it would be better to target net-next tree since it's not a fix or something else important.
quoted hunk ↗ jump to hunk
--- include/trace/events/icmp.h | 64 +++++++++++++++++++++++++++++++++++++ net/ipv4/icmp.c | 4 +++ 2 files changed, 68 insertions(+) create mode 100644 include/trace/events/icmp.hdiff --git a/include/trace/events/icmp.h b/include/trace/events/icmp.h new file mode 100644 index 000000000000..2098d4b1b12e --- /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(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); + 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; + }
What about using the TP_STORE_ADDR_PORTS_SKB macro to record the sport and dport like the patch[1] did through extending the use of header for TCP and UDP? And, I wonder what the use of tracing ulen of that skb? [1]: https://lore.kernel.org/all/1c7156a3f164eb33ef3a25b8432e359f0bb60a8e.1710866188.git.balazs.scheidler@axoflow.com/ (local) Thanks, Jason
quoted hunk ↗ jump to hunk
+ + 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 filediff --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(); --2.44.0