o add BIOCGDLTLIST and BIOCSDLT ioctls to get the data link type list

  and set the link type for use by libpcap and tcpdump
o move mtx unlock in bpfdetach up; it doesn't need to be held so long
o change printf in bpf_detach to distinguish it from the same one in bpfsetdlt

Note there are locking issues here related to ioctl processing; they
have not been addressed here.

Submitted by:	Guy Harris <guy@alum.mit.edu>
Obtained from:	NetBSD (w/ locking modifications)

1 files changed, 10 insertions, 0 deletions

diff --git a/sys/net/bpf.h b/sys/net/bpf.h
index 5e931ce..6d3e800 100644
--- a/sys/net/bpf.h
+++ b/sys/net/bpf.h
@@ -115,6 +115,8 @@ struct bpf_version {
 #define BIOCSHDRCMPLT	_IOW('B',117, u_int)
 #define BIOCGSEESENT	_IOR('B',118, u_int)
 #define BIOCSSEESENT	_IOW('B',119, u_int)
+#define	BIOCSDLT	_IOW('B',120, u_int)
+#define	BIOCGDLTLIST	_IOWR('B',121, struct bpf_dltlist)
 
 /*
  * Structure prepended to each packet.
@@ -339,6 +341,14 @@ struct bpf_insn {
 #define BPF_STMT(code, k) { (u_short)(code), 0, 0, k }
 #define BPF_JUMP(code, k, jt, jf) { (u_short)(code), jt, jf, k }
 
+/*
+ * Structure to retrieve available DLTs for the interface.
+ */
+struct bpf_dltlist {
+	u_int	bfl_len;	/* number of bfd_list array */
+	u_int	*bfl_list;	/* array of DLTs */
+};
+
 #ifdef _KERNEL
 struct bpf_if;
 int	 bpf_validate(const struct bpf_insn *, int);