Implement flexible BPF timestamping framework.

- Allow setting format, resolution and accuracy of BPF time stamps per
listener.  Previously, we were only able to use microtime(9).  Now we can
set various resolutions and accuracies with ioctl(2) BIOCSTSTAMP command.
Similarly, we can get the current resolution and accuracy with BIOCGTSTAMP
command.  Document all supported options in bpf(4) and their uses.

- Introduce new time stamp 'struct bpf_ts' and header 'struct bpf_xhdr'.
The new time stamp has both 64-bit second and fractional parts.  bpf_xhdr
has this time stamp instead of 'struct timeval' for bh_tstamp.  The new
structures let us use bh_tstamp of same size on both 32-bit and 64-bit
platforms without adding additional shims for 32-bit binaries.  On 64-bit
platforms, size of BPF header does not change compared to bpf_hdr as its
members are already all 64-bit long.  On 32-bit platforms, the size may
increase by 8 bytes.  For backward compatibility, struct bpf_hdr with
struct timeval is still the default header unless new time stamp format is
explicitly requested.  However, the behaviour may change in the future and
all relevant code is wrapped around "#ifdef BURN_BRIDGES" for now.

- Add experimental support for tagging mbufs with time stamps from a lower
layer, e.g., device driver.  Currently, mbuf_tags(9) is used to tag mbufs.
The time stamps must be uptime in 'struct bintime' format as binuptime(9)
and getbinuptime(9) do.

Reviewed by:	net@

1 files changed, 75 insertions, 37 deletions

diff --git a/sys/net/bpf.h b/sys/net/bpf.h
index 726483a..b1aad51 100644
--- a/sys/net/bpf.h
+++ b/sys/net/bpf.h
@@ -45,6 +45,8 @@
 
 typedef	int32_t	  bpf_int32;
 typedef	u_int32_t bpf_u_int32;
+typedef	int64_t	  bpf_int64;
+typedef	u_int64_t bpf_u_int64;
 
 /*
  * Alignment macros.  BPF_WORDALIGN rounds up to the next
@@ -113,36 +115,38 @@ struct bpf_zbuf {
 	size_t	 bz_buflen;	/* Size of zero-copy buffers. */
 };
 
-#define	BIOCGBLEN	_IOR('B',102, u_int)
-#define	BIOCSBLEN	_IOWR('B',102, u_int)
-#define	BIOCSETF	_IOW('B',103, struct bpf_program)
-#define	BIOCFLUSH	_IO('B',104)
-#define BIOCPROMISC	_IO('B',105)
-#define	BIOCGDLT	_IOR('B',106, u_int)
-#define BIOCGETIF	_IOR('B',107, struct ifreq)
-#define BIOCSETIF	_IOW('B',108, struct ifreq)
-#define BIOCSRTIMEOUT	_IOW('B',109, struct timeval)
-#define BIOCGRTIMEOUT	_IOR('B',110, struct timeval)
-#define BIOCGSTATS	_IOR('B',111, struct bpf_stat)
-#define BIOCIMMEDIATE	_IOW('B',112, u_int)
-#define BIOCVERSION	_IOR('B',113, struct bpf_version)
-#define BIOCGRSIG	_IOR('B',114, u_int)
-#define BIOCSRSIG	_IOW('B',115, u_int)
-#define BIOCGHDRCMPLT	_IOR('B',116, u_int)
-#define BIOCSHDRCMPLT	_IOW('B',117, u_int)
-#define BIOCGDIRECTION	_IOR('B',118, u_int)
-#define BIOCSDIRECTION	_IOW('B',119, u_int)
-#define	BIOCSDLT	_IOW('B',120, u_int)
-#define	BIOCGDLTLIST	_IOWR('B',121, struct bpf_dltlist)
+#define	BIOCGBLEN	_IOR('B', 102, u_int)
+#define	BIOCSBLEN	_IOWR('B', 102, u_int)
+#define	BIOCSETF	_IOW('B', 103, struct bpf_program)
+#define	BIOCFLUSH	_IO('B', 104)
+#define	BIOCPROMISC	_IO('B', 105)
+#define	BIOCGDLT	_IOR('B', 106, u_int)
+#define	BIOCGETIF	_IOR('B', 107, struct ifreq)
+#define	BIOCSETIF	_IOW('B', 108, struct ifreq)
+#define	BIOCSRTIMEOUT	_IOW('B', 109, struct timeval)
+#define	BIOCGRTIMEOUT	_IOR('B', 110, struct timeval)
+#define	BIOCGSTATS	_IOR('B', 111, struct bpf_stat)
+#define	BIOCIMMEDIATE	_IOW('B', 112, u_int)
+#define	BIOCVERSION	_IOR('B', 113, struct bpf_version)
+#define	BIOCGRSIG	_IOR('B', 114, u_int)
+#define	BIOCSRSIG	_IOW('B', 115, u_int)
+#define	BIOCGHDRCMPLT	_IOR('B', 116, u_int)
+#define	BIOCSHDRCMPLT	_IOW('B', 117, u_int)
+#define	BIOCGDIRECTION	_IOR('B', 118, u_int)
+#define	BIOCSDIRECTION	_IOW('B', 119, u_int)
+#define	BIOCSDLT	_IOW('B', 120, u_int)
+#define	BIOCGDLTLIST	_IOWR('B', 121, struct bpf_dltlist)
 #define	BIOCLOCK	_IO('B', 122)
-#define	BIOCSETWF	_IOW('B',123, struct bpf_program)
-#define	BIOCFEEDBACK	_IOW('B',124, u_int)
-#define	BIOCGETBUFMODE	_IOR('B',125, u_int)
-#define	BIOCSETBUFMODE	_IOW('B',126, u_int)
-#define	BIOCGETZMAX	_IOR('B',127, size_t)
-#define	BIOCROTZBUF	_IOR('B',128, struct bpf_zbuf)
-#define	BIOCSETZBUF	_IOW('B',129, struct bpf_zbuf)
-#define	BIOCSETFNR	_IOW('B',130, struct bpf_program)
+#define	BIOCSETWF	_IOW('B', 123, struct bpf_program)
+#define	BIOCFEEDBACK	_IOW('B', 124, u_int)
+#define	BIOCGETBUFMODE	_IOR('B', 125, u_int)
+#define	BIOCSETBUFMODE	_IOW('B', 126, u_int)
+#define	BIOCGETZMAX	_IOR('B', 127, size_t)
+#define	BIOCROTZBUF	_IOR('B', 128, struct bpf_zbuf)
+#define	BIOCSETZBUF	_IOW('B', 129, struct bpf_zbuf)
+#define	BIOCSETFNR	_IOW('B', 130, struct bpf_program)
+#define	BIOCGTSTAMP	_IOR('B', 131, u_int)
+#define	BIOCSTSTAMP	_IOW('B', 132, u_int)
 
 /* Obsolete */
 #define	BIOCGSEESENT	BIOCGDIRECTION
@@ -155,9 +159,48 @@ enum bpf_direction {
 	BPF_D_OUT	/* See outgoing packets */
 };
 
+/* Time stamping functions */
+#define	BPF_T_MICROTIME		0x0000
+#define	BPF_T_NANOTIME		0x0001
+#define	BPF_T_BINTIME		0x0002
+#define	BPF_T_NONE		0x0003
+#define	BPF_T_FORMAT_MASK	0x0003
+#define	BPF_T_NORMAL		0x0000
+#define	BPF_T_FAST		0x0100
+#define	BPF_T_MONOTONIC		0x0200
+#define	BPF_T_MONOTONIC_FAST	(BPF_T_FAST | BPF_T_MONOTONIC)
+#define	BPF_T_FLAG_MASK		0x0300
+#define	BPF_T_FORMAT(t)		((t) & BPF_T_FORMAT_MASK)
+#define	BPF_T_FLAG(t)		((t) & BPF_T_FLAG_MASK)
+#define	BPF_T_VALID(t)						\
+    ((t) == BPF_T_NONE || (BPF_T_FORMAT(t) != BPF_T_NONE &&	\
+    ((t) & ~(BPF_T_FORMAT_MASK | BPF_T_FLAG_MASK)) == 0))
+
+#define	BPF_T_MICROTIME_FAST		(BPF_T_MICROTIME | BPF_T_FAST)
+#define	BPF_T_NANOTIME_FAST		(BPF_T_NANOTIME | BPF_T_FAST)
+#define	BPF_T_BINTIME_FAST		(BPF_T_BINTIME | BPF_T_FAST)
+#define	BPF_T_MICROTIME_MONOTONIC	(BPF_T_MICROTIME | BPF_T_MONOTONIC)
+#define	BPF_T_NANOTIME_MONOTONIC	(BPF_T_NANOTIME | BPF_T_MONOTONIC)
+#define	BPF_T_BINTIME_MONOTONIC		(BPF_T_BINTIME | BPF_T_MONOTONIC)
+#define	BPF_T_MICROTIME_MONOTONIC_FAST	(BPF_T_MICROTIME | BPF_T_MONOTONIC_FAST)
+#define	BPF_T_NANOTIME_MONOTONIC_FAST	(BPF_T_NANOTIME | BPF_T_MONOTONIC_FAST)
+#define	BPF_T_BINTIME_MONOTONIC_FAST	(BPF_T_BINTIME | BPF_T_MONOTONIC_FAST)
+
 /*
  * Structure prepended to each packet.
  */
+struct bpf_ts {
+	bpf_int64	bt_sec;		/* seconds */
+	bpf_u_int64	bt_frac;	/* fraction */
+};
+struct bpf_xhdr {
+	struct bpf_ts	bh_tstamp;	/* time stamp */
+	bpf_u_int32	bh_caplen;	/* length of captured portion */
+	bpf_u_int32	bh_datalen;	/* original length of packet */
+	u_short		bh_hdrlen;	/* length of bpf header (this struct
+					   plus alignment padding) */
+};
+/* Obsolete */
 struct bpf_hdr {
 	struct timeval	bh_tstamp;	/* time stamp */
 	bpf_u_int32	bh_caplen;	/* length of captured portion */
@@ -165,14 +208,9 @@ struct bpf_hdr {
 	u_short		bh_hdrlen;	/* length of bpf header (this struct
 					   plus alignment padding) */
 };
-/*
- * Because the structure above is not a multiple of 4 bytes, some compilers
- * will insist on inserting padding; hence, sizeof(struct bpf_hdr) won't work.
- * Only the kernel needs to know about it; applications use bh_hdrlen.
- */
 #ifdef _KERNEL
-#define	SIZEOF_BPF_HDR	(sizeof(struct bpf_hdr) <= 20 ? 18 : \
-    sizeof(struct bpf_hdr))
+#define	MTAG_BPF		0x627066
+#define	MTAG_BPF_TIMESTAMP	0
 #endif
 
 /*
@@ -922,7 +960,7 @@ struct bpf_if {
 	LIST_ENTRY(bpf_if)	bif_next;	/* list of all interfaces */
 	LIST_HEAD(, bpf_d)	bif_dlist;	/* descriptor list */
 	u_int bif_dlt;				/* link layer type */
-	u_int bif_hdrlen;		/* length of header (with padding) */
+	u_int bif_hdrlen;		/* length of link header */
 	struct ifnet *bif_ifp;		/* corresponding interface */
 	struct mtx	bif_mtx;	/* mutex for interface */
 };