From: dlg <dlg@openbsd.org>
Date: Thu, 15 Aug 2024 12:20:20 +0000 (+0000)
Subject: add BIOCSETFNR, which is like BIOCSETF but doesnt reset the buffer or stats.
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=e88074f01b958bb51375ab25f05027bc6f0732ca;p=openbsd

add BIOCSETFNR, which is like BIOCSETF but doesnt reset the buffer or stats.

from Matthew Luckie <mjl@luckie.org.nz> via tech@
deraadt@ likes it.
---

diff --git a/share/man/man4/bpf.4 b/share/man/man4/bpf.4
index 4990dc8a109..2c5d476c671 100644
--- a/share/man/man4/bpf.4
+++ b/share/man/man4/bpf.4
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: bpf.4,v 1.46 2024/08/05 23:56:10 dlg Exp $
+.\"	$OpenBSD: bpf.4,v 1.47 2024/08/15 12:20:20 dlg Exp $
 .\"     $NetBSD: bpf.4,v 1.7 1995/09/27 18:31:50 thorpej Exp $
 .\"
 .\" Copyright (c) 1990 The Regents of the University of California.
@@ -23,7 +23,7 @@
 .\" This document is derived in part from the enet man page (enet.4)
 .\" distributed with 4.3BSD Unix.
 .\"
-.Dd $Mdocdate: August 5 2024 $
+.Dd $Mdocdate: August 15 2024 $
 .Dt BPF 4
 .Os
 .Sh NAME
@@ -318,6 +318,7 @@ readable.
 The maximum wait time that can be set is 5 minutes (300 seconds).
 .Pp
 .It Dv BIOCSETF Fa "struct bpf_program *"
+.It Dv BIOCSETFNR Fa "struct bpf_program *"
 Sets the filter program used by the kernel to discard uninteresting packets.
 An array of instructions and its length are passed in using the following
 structure:
@@ -335,9 +336,11 @@ field, while its length in units of
 is given by the
 .Fa bf_len
 field.
-Also, the actions of
+If
+.Dv BIOCSETF
+is used, the actions of
 .Dv BIOCFLUSH
-are performed.
+are also performed.
 .Pp
 See section
 .Sx FILTER MACHINE
@@ -350,8 +353,6 @@ network.
 See
 .Dv BIOCSETF
 for a description of the filter program.
-This ioctl also acts as
-.Dv BIOCFLUSH .
 .Pp
 Note that the filter operates on the packet data written to the descriptor.
 If the
diff --git a/sys/net/bpf.c b/sys/net/bpf.c
index b7c2f1bfd71..d77ad57ace4 100644
--- a/sys/net/bpf.c
+++ b/sys/net/bpf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bpf.c,v 1.224 2024/08/12 17:02:58 mvs Exp $	*/
+/*	$OpenBSD: bpf.c,v 1.225 2024/08/15 12:20:20 dlg Exp $	*/
 /*	$NetBSD: bpf.c,v 1.33 1997/02/21 23:59:35 thorpej Exp $	*/
 
 /*
@@ -760,7 +760,8 @@ bpf_get_wtimeout(struct bpf_d *d, struct timeval *tv)
 /*
  *  FIONREAD		Check for read packet available.
  *  BIOCGBLEN		Get buffer len [for read()].
- *  BIOCSETF		Set ethernet read filter.
+ *  BIOCSETF		Set read filter.
+ *  BIOCSETFNR          Set read filter without resetting descriptor.
  *  BIOCFLUSH		Flush read packet buffer.
  *  BIOCPROMISC		Put interface into promiscuous mode.
  *  BIOCGDLTLIST	Get supported link layer types.
@@ -867,17 +868,12 @@ bpfioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *p)
 		break;
 
 	/*
-	 * Set link layer read filter.
+	 * Set link layer read/write filter.
 	 */
 	case BIOCSETF:
-		error = bpf_setf(d, (struct bpf_program *)addr, 0);
-		break;
-
-	/*
-	 * Set link layer write filter.
-	 */
+	case BIOCSETFNR:
 	case BIOCSETWF:
-		error = bpf_setf(d, (struct bpf_program *)addr, 1);
+		error = bpf_setf(d, (struct bpf_program *)addr, cmd);
 		break;
 
 	/*
@@ -1122,7 +1118,7 @@ bpfioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, struct proc *p)
  * free it and replace it.  Returns EINVAL for bogus requests.
  */
 int
-bpf_setf(struct bpf_d *d, struct bpf_program *fp, int wf)
+bpf_setf(struct bpf_d *d, struct bpf_program *fp, u_long cmd)
 {
 	struct bpf_program_smr *bps, *old_bps;
 	struct bpf_insn *fcode;
@@ -1157,7 +1153,7 @@ bpf_setf(struct bpf_d *d, struct bpf_program *fp, int wf)
 		bps->bps_bf.bf_insns = fcode;
 	}
 
-	if (wf == 0) {
+	if (cmd != BIOCSETWF) {
 		old_bps = SMR_PTR_GET_LOCKED(&d->bd_rfilter);
 		SMR_PTR_SET_LOCKED(&d->bd_rfilter, bps);
 	} else {
@@ -1165,9 +1161,12 @@ bpf_setf(struct bpf_d *d, struct bpf_program *fp, int wf)
 		SMR_PTR_SET_LOCKED(&d->bd_wfilter, bps);
 	}
 
-	mtx_enter(&d->bd_mtx);
-	bpf_resetd(d);
-	mtx_leave(&d->bd_mtx);
+	if (cmd == BIOCSETF) {
+		mtx_enter(&d->bd_mtx);
+		bpf_resetd(d);
+		mtx_leave(&d->bd_mtx);
+	}
+
 	if (old_bps != NULL)
 		smr_call(&old_bps->bps_smr, bpf_prog_smr, old_bps);
 
diff --git a/sys/net/bpf.h b/sys/net/bpf.h
index ab64061fb97..91b367c132e 100644
--- a/sys/net/bpf.h
+++ b/sys/net/bpf.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bpf.h,v 1.72 2024/01/26 21:14:08 jan Exp $	*/
+/*	$OpenBSD: bpf.h,v 1.73 2024/08/15 12:20:20 dlg Exp $	*/
 /*	$NetBSD: bpf.h,v 1.15 1996/12/13 07:57:33 mikel Exp $	*/
 
 /*
@@ -122,6 +122,7 @@ struct bpf_version {
 #define BIOCSWTIMEOUT	_IOW('B',126, struct timeval)
 #define BIOCGWTIMEOUT	_IOR('B',126, struct timeval)
 #define BIOCDWTIMEOUT	_IO('B',126)
+#define BIOCSETFNR	_IOW('B',127, struct bpf_program)
 
 /*
  * Direction filters for BIOCSDIRFILT/BIOCGDIRFILT
diff --git a/sys/net/bpfdesc.h b/sys/net/bpfdesc.h
index 76b75ff5a20..4b558c4eb80 100644
--- a/sys/net/bpfdesc.h
+++ b/sys/net/bpfdesc.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bpfdesc.h,v 1.48 2023/03/09 05:56:58 dlg Exp $	*/
+/*	$OpenBSD: bpfdesc.h,v 1.49 2024/08/15 12:20:20 dlg Exp $	*/
 /*	$NetBSD: bpfdesc.h,v 1.11 1995/09/27 18:30:42 thorpej Exp $	*/
 
 /*
@@ -123,6 +123,6 @@ struct bpf_if {
 	struct ifnet *bif_ifp;		/* corresponding interface */
 };
 
-int	 bpf_setf(struct bpf_d *, struct bpf_program *, int);
+int	 bpf_setf(struct bpf_d *, struct bpf_program *, u_long);
 #endif /* _KERNEL */
 #endif /* _NET_BPFDESC_H_ */