From 638afbfe26ca92fef3a6814a42ec2eb750d940b4 Mon Sep 17 00:00:00 2001
From: jonathan <jonathan@NetBSD.org>
Date: Thu, 22 Jan 2004 00:32:41 +0000
Subject: [PATCH] Make bpf_maxbufsize writable via sysctl, as written by Andrew
 Brown.

---
 sys/net/bpf.c | 55 +++++++++++++++++++++++++++++++++++++++++++++------
 sys/net/bpf.h |  5 +++--
 2 files changed, 52 insertions(+), 8 deletions(-)

diff --git a/sys/net/bpf.c b/sys/net/bpf.c
index a1c561aed228..c354469f8c3b 100644
--- a/sys/net/bpf.c
+++ b/sys/net/bpf.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: bpf.c,v 1.88 2004/01/21 23:59:12 jonathan Exp $	*/
+/*	$NetBSD: bpf.c,v 1.89 2004/01/22 00:32:41 jonathan Exp $	*/
 
 /*
  * Copyright (c) 1990, 1991, 1993
@@ -39,7 +39,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: bpf.c,v 1.88 2004/01/21 23:59:12 jonathan Exp $");
+__KERNEL_RCSID(0, "$NetBSD: bpf.c,v 1.89 2004/01/22 00:32:41 jonathan Exp $");
 
 #include "bpfilter.h"
 
@@ -63,6 +63,7 @@ __KERNEL_RCSID(0, "$NetBSD: bpf.c,v 1.88 2004/01/21 23:59:12 jonathan Exp $");
 #include <sys/errno.h>
 #include <sys/kernel.h>
 #include <sys/poll.h>
+#include <sys/sysctl.h>
 
 #include <net/if.h>
 
@@ -90,12 +91,12 @@ __KERNEL_RCSID(0, "$NetBSD: bpf.c,v 1.88 2004/01/21 23:59:12 jonathan Exp $");
 #define PRINET  26			/* interruptible */
 
 /*
- * The default read buffer size, and limit for BIOCSBLEN, is patchable.
- * XXX both should be made sysctl'able, and the defaults computed
- * dynamically based on available memory size and available mbuf clusters.
+ * The default read buffer size, and limit for BIOCSBLEN, is sysctl'able.
+ * XXX the default values should be computed dynamically based
+ * on available memory size and available mbuf clusters.
  */
 int bpf_bufsize = BPF_BUFSIZE;
-int bpf_maxbufsize = (1024 *  1024);	/* XXX set dynamically, see above */
+int bpf_maxbufsize = BPF_DFLTBUFSIZE;	/* XXX set dynamically, see above */
 
 /*
  *  bpf_iflist is the list of interfaces; each corresponds to an ifnet
@@ -1493,3 +1494,45 @@ bpf_setdlt(d, dlt)
 	splx(s);
 	return 0;
 }
+
+static int
+sysctl_net_bpf_maxbufsize(SYSCTLFN_ARGS)
+{
+	int newsize, error;
+	struct sysctlnode node;
+
+	node = *rnode;
+	node.sysctl_data = &newsize;
+	newsize = bpf_maxbufsize;
+	error = sysctl_lookup(SYSCTLFN_CALL(&node));
+	if (error || newp == NULL)
+		return (error);
+
+	if (newsize < BPF_MINBUFSIZE || newsize > BPF_MAXBUFSIZE)
+		return (EINVAL);
+
+	bpf_maxbufsize = newsize;
+
+	return (0);
+}
+
+SYSCTL_SETUP(sysctl_net_bfp_setup, "sysctl net.bpf subtree setup")
+{
+	struct sysctlnode *node;
+
+	sysctl_createv(SYSCTL_PERMANENT,
+		       CTLTYPE_NODE, "net", NULL,
+		       NULL, 0, NULL, 0,
+		       CTL_NET, CTL_EOL);
+
+	node = NULL;
+	sysctl_createv(SYSCTL_PERMANENT,
+		       CTLTYPE_NODE, "bpf", &node,
+		       NULL, 0, NULL, 0,
+		       CTL_NET, CTL_CREATE, CTL_EOL);
+	if (node != NULL)
+		sysctl_createv(SYSCTL_PERMANENT|SYSCTL_READWRITE,
+			CTLTYPE_INT, "maxbufsize", NULL,
+			sysctl_net_bpf_maxbufsize, 0, &bpf_maxbufsize, 0,
+			CTL_NET, node->sysctl_num, CTL_CREATE, CTL_EOL);
+}
diff --git a/sys/net/bpf.h b/sys/net/bpf.h
index 8d5581f4a7ee..3a3623696fe3 100644
--- a/sys/net/bpf.h
+++ b/sys/net/bpf.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: bpf.h,v 1.32 2003/08/07 16:32:47 agc Exp $	*/
+/*	$NetBSD: bpf.h,v 1.33 2004/01/22 00:32:41 jonathan Exp $	*/
 
 /*
  * Copyright (c) 1990, 1991, 1993
@@ -56,7 +56,8 @@ typedef	u_int bpf_u_int32;
 #define BPF_WORDALIGN(x) (((x)+(BPF_ALIGNMENT-1))&~(BPF_ALIGNMENT-1))
 
 #define BPF_MAXINSNS 512
-#define BPF_MAXBUFSIZE 0x8000
+#define BPF_DFLTBUFSIZE (1024*1024)	/* default static upper limit */
+#define BPF_MAXBUFSIZE (1024*1024*16)	/* hard limit on sysctl'able value */
 #define BPF_MINBUFSIZE 32
 
 /*