=== DF-0672 environment (guest) ===
uname -a    : DragonFly dfbsd 6.5-DEVELOPMENT DragonFly 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026     root@dfbsd:/usr/obj/usr/src/sys/X86_64_GENERIC  x86_64
kern.version: DragonFly 6.5-DEVELOPMENT #0: Thu Jul  2 06:02:54 UTC 2026
cc          : cc 8.3 [DragonFly] Release/2019-02-22

Cited file is built into smbfs.ko (optional netsmb). After kldload smbfs:
  $ nm /boot/kernel/smbfs.ko | grep -E 'nbssn_rq_request|nb_connect_in'
  0000000000003590 t nb_connect_in
  00000000000037e0 t nbssn_rq_request

(Not built into the base kernel: `nm /boot/kernel/kernel | grep
nbssn_rq_request` returns no matches until smbfs.ko is loaded.)