Re: Re: Re: [PATCH v3 resend] net/ipv4: add tracepoint for icmp_send

Peilin He
2024-03-25T07:58:24Z

>> >> ---------
>> >> v2->v3:
>> >> Some fixes according to
>> >> https://lore.kernel.org/all/20240319102549.7f7f6f53@gandalf.local.home=
>/
>> >> 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=3D3DsZtRnKRu_tnUwqHuFQT=
>JvJsv=3D
>> >-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>
>> >
>> >I think it would be better to target net-next tree since it's not a
>> >fix or something else important.
>> >
>> OK. I would target it for net-next.
>> >> ---
>> >> 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..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 =3D3D ip_hdr(skb);
>> >> + int proto_4 =3D3D iph->protocol;
>> >> + __be32 *p32;
>> >> +
>> >> + __entry->skbaddr =3D3D skb;
>> >> + __entry->type =3D3D type;
>> >> + __entry->code =3D3D code;
>> >> +
>> >> + if (proto_4 =3D3D=3D3D IPPROTO_UDP) {
>> >> + struct udphdr *uh =3D3D udp_hdr(skb);
>> >> + __entry->sport =3D3D ntohs(uh->source)=
>;
>> >> + __entry->dport =3D3D ntohs(uh->dest);
>> >> + __entry->ulen =3D3D ntohs(uh->len);
>> >> + } else {
>> >> + __entry->sport =3D3D 0;
>> >> + __entry->dport =3D3D 0;
>> >> + __entry->ulen =3D3D 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?
>> >
>> I believe patch[1] is a good idea as it moves the TCP protocol parsing
>> previously done inside the TP_STORE_ADDR_PORTS_SKB macro to TP_fast_assig=
>n,
>> and extracts the TP_STORE_ADDR_PORTS_SKB macro into a common file,
>> enabling support for both UDP and TCP protocol parsing simultaneously.
>>
>> However, patch[1] only extracts the source and destination addresses of
>> the packet, but does not extract the source port and destination port,
>> which limits the significance of my submitted patch.
>
>No, please take a look at TP_STORE_ADDR_PORTS_SKB() macro again. It
>records 4-tuples of the flow.
>
>Thanks,
>Jason
>
Okay, after patch [1] is merged, we will propose an optimization patch based on it.
>>
>> Perhaps the patch[1] could be referenced for integration after it is merg=
>ed.
>> >And, I wonder what the use of tracing ulen of that skb?
>> >
>> The tracking of ulen is primarily aimed at ensuring the legality of recei=
>ved
>> UDP packets and providing developers with more detailed information
>> on exceptions. See net/ipv4/udp.c:2494-2501.
>> >[1]: https://lore.kernel.org/all/1c7156a3f164eb33ef3a25b8432e359f0bb60a8=
>e.1=3D
>> >710866188.git.balazs.scheidler@axoflow.com/
>> >
>> >Thanks,
>> >Jason
>> >
>> >> +
>> >> + p32 =3D3D (__be32 *) __entry->saddr;
>> >> + *p32 =3D3D iph->saddr;
>> >> +
>> >> + p32 =3D3D (__be32 *) __entry->daddr;
>> >> + *p32 =3D3D iph->daddr;
>> >> + ),
>> >> +
>> >> + TP_printk("icmp_send: type=3D3D%d, code=3D3D%d. From %=
>pI4:%u =3D
>> >to %pI4:%u ulen=3D3D%d skbaddr=3D3D%p",
>> >> + __entry->type, __entry->code,
>> >> + __entry->saddr, __entry->sport, __entry->daddr=
>,
>> >> + __entry->dport, __entry->ulen, __entry->skbadd=
>r)
>> >> +);
>> >> +
>> >> +#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,=
> in=3D
>> >t 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