On Fri, Apr 26, 2024 at 10:47 AM <xu.xi...@zte.com.cn> wrote:
>
> From: Peilin He <he.pei...@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/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
>
> Change log:
> ===========
> v6->v7:
> Some fixes according to
> https://lore.kernel.org/all/20240425081210.720a4...@kernel.org/
> 1. Fix patch format issues.
>
> v5->v6:
> Some fixes according to
> https://lore.kernel.org/all/20240413161319.ga853...@kernel.org/
> 1.Resubmit patches based on the latest net-next code.
>
> v4->v5:
> Some fixes according to
> https://lore.kernel.org/all/CAL+tcoDeXXh+zcRk4PHnUk8ELnx=CE2pc
> cqs7sfm0y9ak-e...@mail.gmail.com/
> 1.Adjust the position of trace_icmp_send() to before icmp_push_reply().
>
> v3->v4:
> Some fixes according to
> https://lore.kernel.org/all/CANn89i+EFEr7VHXNdOi59Ba_R1nFKSBJz
> BzkJFVgCTdXBx=y...@mail.gmail.com/
> 1.Add legality check for UDP header in SKB.
> 2.Target this patch for net-next.
>
> v2->v3:
> Some fixes according to
> https://lore.kernel.org/all/20240319102549.7f7f6...@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=sZtRnKRu_tnUwqHu
> fqtjvjsv-nz1x...@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.pei...@zte.com.cn>
> Signed-off-by: xu xin <xu.xi...@zte.com.cn>
> Reviewed-by: Yunkai Zhang <zhang.yun...@zte.com.cn>
> Cc: Yang Yang <yang.yan...@zte.com.cn>
> Cc: Liu Chun <liu.ch...@zte.com.cn>
> Cc: Xuexin Jiang <jiang.xue...@zte.com.cn>
> ---
> include/trace/events/icmp.h | 68 +++++++++++++++++++++++++++++++++++++
> net/ipv4/icmp.c | 4 +++
> 2 files changed, 72 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..cff33aaee44e
> --- /dev/null
> +++ b/include/trace/events/icmp.h
> @@ -0,0 +1,68 @@
> +/* 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;
> +
> + struct udphdr *uh = udp_hdr(skb);
Please move this line up., perhaps after the "struct iphdr *iph =
ip_hdr(skb);" one
We group all variable definitions together, we do not mix code and variables.
> +
> + 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);
> + }
> +
