kern/57959: icmp6_reflect prints confusing error message to console without attribution

[campbell+netbsd%mumble.net@localhost]

>Number:         57959
>Category:       kern
>Synopsis:       icmp6_reflect prints confusing error message to console without attribution
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Feb 23 23:15:00 +0000 2024
>Originator:     Taylor R Campbell
>Release:        10.0_RC3
>Organization:
The NdpBSD Foundation
>Environment:
NetBSD nanocons.local 10.0_RC3 NetBSD 10.0_RC3 (GENERIC64) #15: Wed Jan 17 05:31:14 UTC 2024  root@manticore.local:/usr/obj/10/evbarm64/sys/arch/evbarm/compile/GENERIC64 evbarm
>Description:
I got this message on the console:

[ 2569129.504153] source can't be determined: dst=10.0.0.3

It is completely obscure what is going on here.  Grepping through the source code I find this message:

https://nxr.netbsd.org/xref/src/sys/netinet6/icmp6.c?r=1.255#2175

   2175 			char ip6buf[INET6_ADDRSTRLEN];
   2176 			nd6log(LOG_DEBUG,
   2177 			    "source can't be determined: "
   2178 			    "dst=%s, error=%d\n",
   2179 			    IN6_PRINT(ip6buf, &sin6.sin6_addr), e);
   2180 			goto bad;

I don't know if this is what caused it (and it seems unlikely because this prints IPv6 addresses, not IPv4 addresses), but if this nd6log call causes an unattributed message to appear on the console, it should be fixed so it at least says `nd6' or something somewhere in the message.
>How-To-Repeat:
no clue
>Fix:
Yes, please!