Add interface description capability as inspired by OpenBSD.

MFC after:	3 months

2 files changed, 64 insertions, 1 deletions

diff --git a/sbin/ifconfig/ifconfig.8 b/sbin/ifconfig/ifconfig.8
index 220bd9f..211b1ef 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 September 23, 2009
+.Dd November 11, 2009
 .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
+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
+Clear the interface description.
 .It Cm down
 Mark an interface
 .Dq down .
@@ -2512,6 +2518,10 @@ 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..e08bb4f 100644
--- a/sbin/ifconfig/ifconfig.c
+++ b/sbin/ifconfig/ifconfig.c
@@ -83,6 +83,8 @@ 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 +824,36 @@ 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;
+
+	newdescr = strdup(val);
+	if (newdescr == NULL) {
+		warn("no memory to set ifdescr");
+		return;
+	}
+	ifr.ifr_buffer.buffer = newdescr;
+	ifr.ifr_buffer.length = strlen(newdescr);
+	if (ioctl(s, SIOCSIFDESCR, (caddr_t)&ifr) < 0) {
+		warn("ioctl (set descr)");
+		free(newdescr);
+		return;
+	}
+	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 +898,23 @@ status(const struct afswtch *afp, const struct sockaddr_dl *sdl,
 		printf(" mtu %d", ifr.ifr_mtu);
 	putchar('\n');
 
+	descr = reallocf(descr, descrlen);
+	if (descr != NULL) {
+		do {
+			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;
+			}
+			if (errno == ENAMETOOLONG) {
+				descrlen *= 2;
+				descr = reallocf(descr, descrlen);
+			}
+		} while (errno == ENAMETOOLONG);
+	}
+
 	if (ioctl(s, SIOCGIFCAP, (caddr_t)&ifr) == 0) {
 		if (ifr.ifr_curcap != 0) {
 			printb("\toptions", ifr.ifr_curcap, IFCAPBITS);
@@ -1035,6 +1084,10 @@ 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),