>[...] >> >I think my understanding based on what Eric depicted differs from you: >> >we're supposed to filter out those many invalid cases and only trace >> >the valid action of sending a icmp, so where to add a new tracepoint >> >is important instead of adding more checks in the tracepoint itself. >> >Please refer to what trace_tcp_retransmit_skb() does :) >> > >> >Thanks, >> >Jason >> Okay, thank you for your suggestion. In order to avoid filtering out >> those many invalid cases and only tracing the valid action of sending >> a icmp, the next patch will add udd_fail_no_port trancepoint to the >> include/trace/events/udp.h. This will solve the problem you mentioned >> very well. At this point, only UDP protocol exceptions will be tracked, >> without the need to track them in icmp_send. > >I'm not against what you did (tracing all the icmp_send() for UDP) in >your original patch. I was suggesting that you could put >trace_icmp_send() in the right place, then you don't have to check the >possible error condition (like if the skb->head is valid or not, ...) >in your trace function. > >One example that can avoid various checks existing in the >__icmp_send() function: >diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c >index e63a3bf99617..2c9f7364de45 100644 >--- a/net/ipv4/icmp.c >+++ b/net/ipv4/icmp.c >@@ -767,6 +767,7 @@ 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); > >If we go here, it means we are ready to send the ICMP skb because >we're done extracting the right information in the 'struct sk_buff >skb_in'. Simpler and easier, right? > >Thanks, >Jason
I may not fully agree with this viewpoint. When trace_icmp_send is placed in this position, it cannot guarantee that all skbs in icmp are UDP protocols (UDP needs to be distinguished based on the proto_4!=IPPROTO_UDP condition), nor can it guarantee the legitimacy of udphdr (*uh legitimacy check is required). With best wishes Peilin He >> >> >> 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=3DsZtRnKRu_tnUwqHuFQTJvJsv= >> >-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> >> >> Reviewed-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 | 65 +++++++++++++++++++++++++++++++++++++ >> >> net/ipv4/icmp.c | 4 +++ >> >> 2 files changed, 69 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..7d5190f48a28 >> >> --- /dev/null >> >> +++ b/include/trace/events/icmp.h >> >> @@ -0,0 +1,65 @@ >> >> +/* 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 =3D ip_hdr(skb); >> >> + int proto_4 =3D iph->protocol; >> >> + __be32 *p32; >> >> + >> >> + __entry->skbaddr =3D skb; >> >> + __entry->type =3D type; >> >> + __entry->code =3D code; >> >> + >> >> + struct udphdr *uh =3D udp_hdr(skb); >> >> + if (proto_4 !=3D IPPROTO_UDP || (u8 *)uh < skb->h= >> >ead || >> >> + (u8 *)uh + sizeof(struct udphdr) > skb_ta= >> >il_pointer(skb)) { >> >> + __entry->sport =3D 0; >> >> + __entry->dport =3D 0; >> >> + __entry->ulen =3D 0; >> >> + } else { >> >> + __entry->sport =3D ntohs(uh->source); >> >> + __entry->dport =3D ntohs(uh->dest); >> >> + __entry->ulen =3D ntohs(uh->len); >> >> + } >> >> + >> >> + p32 =3D (__be32 *) __entry->saddr; >> >> + *p32 =3D iph->saddr; >> >> + >> >> + p32 =3D (__be32 *) __entry->daddr; >> >> + *p32 =3D iph->daddr; >> >> + ), >> >> + >> >> + TP_printk("icmp_send: type=3D%d, code=3D%d. From %pI4:%u = >> >to %pI4:%u ulen=3D%d skbaddr=3D%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 file >> >> diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c >> >> index 8cebb476b3ab..224551d75c02 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= >> >t code, __be32 info, >> >> } >> >> } >> >> >> >> + trace_icmp_send(skb_in, type, code); >> >> + >> >> /* Needed by both icmp_global_allow and icmp_xmit_lock */ >> >> local_bh_disable(); >> >> >> >> -- >> >> 2.25.1
