The list of permitted ioctls in the description of BIOCLOCK in BPF(4) is incomplete - BIOCGDIRFILT is also allowed, according to sys/net/bpf.c.
Here's a patch.
Index: share/man/man4/bpf.4 =================================================================== RCS file: /cvs/src/share/man/man4/bpf.4,v retrieving revision 1.36 diff -u -r1.36 bpf.4 --- share/man/man4/bpf.4 16 Jan 2015 03:07:03 -0000 1.36 +++ share/man/man4/bpf.4 10 Mar 2016 02:21:15 -0000 @@ -222,6 +222,7 @@ .Dv BIOCGBLEN , .Dv BIOCGDIRFILT , .Dv BIOCGDLT , +.Dv BIOCGDIRFILT , .Dv BIOCGDLTLIST , .Dv BIOCGETIF , .Dv BIOCGHDRCMPLT ,
