MFC 203052:

Add interface description capability as inspired by OpenBSD.  Thanks for
rwatson@, jhb@, brooks@ and others for feedback to the old implementation!

Sponsored by:	iXsystems, Inc.

2 files changed, 70 insertions, 2 deletions

diff --git a/sbin/ifconfig/ifconfig.8 b/sbin/ifconfig/ifconfig.8
index c372a08..32e8fa3 100644
--- a/sbin/ifconfig/ifconfig.8
+++ b/sbin/ifconfig/ifconfig.8
@@ -28,7 +28,7 @@
 .\"     From: @(#)ifconfig.8	8.3 (Berkeley) 1/5/94
 .\" $FreeBSD$
 .\"
-.Dd December 7, 2009
+.Dd January 26, 2010
 .Dt IFCONFIG 8
 .Os
 .Sh NAME
@@ -258,6 +258,12 @@ Disable permanently promiscuous mode.
 Another name for the
 .Fl alias
 parameter.
+.It Cm description Ar value , Cm descr Ar value
+Specify a description of the interface.
+This can be used to label interfaces in situations where they may
+otherwise be difficult to distinguish.
+.It Cm -description , Cm -descr
+Clear the interface description.
 .It Cm down
 Mark an interface
 .Dq down .
@@ -2493,6 +2499,10 @@ Configure the interface
 to use 100baseTX, full duplex Ethernet media options:
 .Dl # ifconfig xl0 media 100baseTX mediaopt full-duplex
 .Pp
+Label the em0 interface as an uplink:
+.Pp
+.Dl # ifconfig em0 description \&"Uplink to Gigabit Switch 2\&"
+.Pp
 Create the software network interface
 .Li gif1 :
 .Dl # ifconfig gif1 create
diff --git a/sbin/ifconfig/ifconfig.c b/sbin/ifconfig/ifconfig.c
index f05374c..ec5e403 100644
--- a/sbin/ifconfig/ifconfig.c
+++ b/sbin/ifconfig/ifconfig.c
@@ -44,7 +44,6 @@ static const char rcsid[] =
 #include <sys/param.h>
 #include <sys/ioctl.h>
 #include <sys/socket.h>
-#include <sys/sysctl.h>
 #include <sys/time.h>
 #include <sys/module.h>
 #include <sys/linker.h>
@@ -83,6 +82,8 @@ static const char rcsid[] =
 struct	ifreq ifr;
 
 char	name[IFNAMSIZ];
+char	*descr = NULL;
+size_t	descrlen = 64;
 int	setaddr;
 int	setmask;
 int	doalias;
@@ -822,6 +823,40 @@ setifname(const char *val, int dummy __unused, int s,
 	free(newname);
 }
 
+/* ARGSUSED */
+static void
+setifdescr(const char *val, int dummy __unused, int s, 
+    const struct afswtch *afp)
+{
+	char *newdescr;
+
+	ifr.ifr_buffer.length = strlen(val) + 1;
+	if (ifr.ifr_buffer.length == 1) {
+		ifr.ifr_buffer.buffer = newdescr = NULL;
+		ifr.ifr_buffer.length = 0;
+	} else {
+		newdescr = strdup(val);
+		ifr.ifr_buffer.buffer = newdescr;
+		if (newdescr == NULL) {
+			warn("no memory to set ifdescr");
+			return;
+		}
+	}
+
+	if (ioctl(s, SIOCSIFDESCR, (caddr_t)&ifr) < 0)
+		warn("ioctl (set descr)");
+
+	free(newdescr);
+}
+
+/* ARGSUSED */
+static void
+unsetifdescr(const char *val, int value, int s, const struct afswtch *afp)
+{
+
+	setifdescr("", 0, s, 0);
+}
+
 #define	IFFBITS \
 "\020\1UP\2BROADCAST\3DEBUG\4LOOPBACK\5POINTOPOINT\6SMART\7RUNNING" \
 "\10NOARP\11PROMISC\12ALLMULTI\13OACTIVE\14SIMPLEX\15LINK0\16LINK1\17LINK2" \
@@ -866,6 +901,25 @@ status(const struct afswtch *afp, const struct sockaddr_dl *sdl,
 		printf(" mtu %d", ifr.ifr_mtu);
 	putchar('\n');
 
+	for (;;) {
+		if ((descr = reallocf(descr, descrlen)) != NULL) {
+			ifr.ifr_buffer.buffer = descr;
+			ifr.ifr_buffer.length = descrlen;
+			if (ioctl(s, SIOCGIFDESCR, &ifr) == 0) {
+				if (strlen(descr) > 0)
+					printf("\tdescription: %s\n", descr);
+				break;
+			} else if (errno == ENAMETOOLONG)
+				descrlen = ifr.ifr_buffer.length;
+			else
+				break;
+		} else {
+			warn("unable to allocate memory for interface"
+			    "description");
+			break;
+		}
+	};
+
 	if (ioctl(s, SIOCGIFCAP, (caddr_t)&ifr) == 0) {
 		if (ifr.ifr_curcap != 0) {
 			printb("\toptions", ifr.ifr_curcap, IFCAPBITS);
@@ -1035,6 +1089,10 @@ static struct cmd basic_cmds[] = {
 	DEF_CMD("-arp",		IFF_NOARP,	setifflags),
 	DEF_CMD("debug",	IFF_DEBUG,	setifflags),
 	DEF_CMD("-debug",	-IFF_DEBUG,	setifflags),
+	DEF_CMD_ARG("description",		setifdescr),
+	DEF_CMD_ARG("descr",			setifdescr),
+	DEF_CMD("-description",	0,		unsetifdescr),
+	DEF_CMD("-descr",	0,		unsetifdescr),
 	DEF_CMD("promisc",	IFF_PPROMISC,	setifflags),
 	DEF_CMD("-promisc",	-IFF_PPROMISC,	setifflags),
 	DEF_CMD("add",		IFF_UP,		notealias),