Add better support for retrieving management information from network

interfaces.  This creates two new tables in the net.link.generic branch
of the MIB; one contains (essentially) `ifdata' structures, and the other
contains a blob provided by the interface (and presumably used to
implement link-layer-specific MIB variables).  A number of things
have been moved around in the `ifnet' and `ifdata' structures, so
NEW VERSIONS OF ifconfig(8) AND routed(8) ARE REQUIRED.  (A simple
recompile is all that's necessary.)

I have a sample program which uses this interface for those interested
in making use of it.

1 files changed, 150 insertions, 0 deletions

diff --git a/sys/net/if_mib.c b/sys/net/if_mib.c
new file mode 100644
index 0000000..bb14745
--- /dev/null
+++ b/sys/net/if_mib.c
@@ -0,0 +1,150 @@
+/*
+ * Copyright 1996 Massachusetts Institute of Technology
+ *
+ * Permission to use, copy, modify, and distribute this software and
+ * its documentation for any purpose and without fee is hereby
+ * granted, provided that both the above copyright notice and this
+ * permission notice appear in all copies, that both the above
+ * copyright notice and this permission notice appear in all
+ * supporting documentation, and that the name of M.I.T. not be used
+ * in advertising or publicity pertaining to distribution of the
+ * software without specific, written prior permission.  M.I.T. makes
+ * no representations about the suitability of this software for any
+ * purpose.  It is provided "as is" without express or implied
+ * warranty.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
+ * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
+ * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	$Id$
+ */
+
+#include <sys/param.h>
+#include <sys/queue.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/errno.h>
+#include <sys/sysctl.h>
+
+#include <net/if.h>
+#include <net/if_dl.h>
+#include <net/if_mib.h>
+#include <net/if_types.h>
+
+/*
+ * A sysctl(3) MIB for generic interface information.  This information
+ * is exported in the net.link.generic branch, which has the following
+ * structure:
+ *
+ * net.link.generic	.system			- system-wide control variables
+ *						  and statistics (node)
+ *			.ifdata.<ifindex>.general
+ *						- what's in `struct ifdata'
+ *						  plus some other info
+ *			.ifdata.<ifindex>.linkspecific
+ *						- a link-type-specific data
+ *						  structure (as might be used
+ *						  by an SNMP agent
+ *
+ * Perhaps someday we will make addresses accessible via this interface
+ * as well (then there will be four such...).  The reason that the
+ * index comes before the last element in the name is because it
+ * seems more orthogonal that way, particularly with the possibility
+ * of other per-interface data living down here as well (e.g., integrated
+ * services stuff).
+ */
+
+SYSCTL_NODE(_net_link_generic, IFMIB_SYSTEM, system, CTLFLAG_RW, 0,
+	    "Variables global to all interfaces");
+SYSCTL_INT(_net_link_generic_system, IFMIB_IFCOUNT, ifcount, CTLFLAG_RD,
+	   &if_index, 0, "Number of configured interfaces");
+
+static int
+sysctl_ifdata SYSCTL_HANDLER_ARGS /* XXX bad syntax! */
+{
+	int *name = (int *)arg1;
+	int error, ifnlen;
+	u_int namelen = arg2;
+	struct ifnet *ifp;
+	char workbuf[64];
+	struct ifmibdata ifmd;
+
+	if (namelen != 2)
+		return EINVAL;
+
+	if (name[0] <= 0 || name[0] > if_index)
+		return ENOENT;
+
+	ifp = ifnet_addrs[name[0] - 1]->ifa_ifp;
+
+	switch(name[1]) {
+	default:
+		return ENOENT;
+
+	case IFDATA_GENERAL:
+		ifnlen = sprintf(workbuf, "%s%d", ifp->if_name, ifp->if_unit);
+		if(ifnlen + 1 > sizeof ifmd.ifmd_name) {
+			return ENAMETOOLONG;
+		} else {
+			strcpy(ifmd.ifmd_name, workbuf);
+		}
+
+#define COPY(fld) ifmd.ifmd_##fld = ifp->if_##fld
+		COPY(pcount);
+		COPY(flags);
+		COPY(data);
+#undef COPY
+		ifmd.ifmd_snd_len = ifp->if_snd.ifq_len;
+		ifmd.ifmd_snd_maxlen = ifp->if_snd.ifq_maxlen;
+		ifmd.ifmd_snd_drops = ifp->if_snd.ifq_drops;
+
+		error = SYSCTL_OUT(req, &ifmd, sizeof ifmd);
+		if (error || !req->newptr)
+			return error;
+
+		error = SYSCTL_IN(req, &ifmd, sizeof ifmd);
+		if (error)
+			return error;
+
+#define DONTCOPY(fld) ifmd.ifmd_data.ifi_##fld = ifp->if_data.ifi_##fld
+		DONTCOPY(type);
+		DONTCOPY(physical);
+		DONTCOPY(addrlen);
+		DONTCOPY(hdrlen);
+		DONTCOPY(mtu);
+		DONTCOPY(metric);
+		DONTCOPY(baudrate);
+#undef DONTCOPY
+#define COPY(fld) ifp->if_##fld = ifmd.ifmd_##fld
+		COPY(data);
+		ifp->if_snd.ifq_maxlen = ifmd.ifmd_snd_maxlen;
+		ifp->if_snd.ifq_drops = ifmd.ifmd_snd_drops;
+#undef COPY
+		break;
+
+	case IFDATA_LINKSPECIFIC:
+		error = SYSCTL_OUT(req, ifp->if_linkmib, ifp->if_linkmiblen);
+		if (error || !req->newptr)
+			return error;
+
+		error = SYSCTL_IN(req, ifp->if_linkmib, ifp->if_linkmiblen);
+		if (error)
+			return error;
+		
+	}
+	return 0;
+}
+
+SYSCTL_NODE(_net_link_generic, IFMIB_IFDATA, ifdata, CTLFLAG_RW,
+	    sysctl_ifdata, "Interface table");
+