From 8b7805e44e9aeaf8fd798a813f000e087eac63b9 Mon Sep 17 00:00:00 2001
From: Boris Popov <bp@FreeBSD.org>
Date: Mon, 13 Dec 1999 15:57:11 +0000
Subject: [PATCH] Allow ifunit() routine to understand names like ed0f2. Also
 fix a bug caused by using bcmp() instead of strcmp().

Reviewed by:	Garrett Wollman <wollman@khavrinen.lcs.mit.edu>
---
 sys/net/if.c | 57 ++++++++++++++++++++++++----------------------------
 1 file changed, 26 insertions(+), 31 deletions(-)

diff --git a/sys/net/if.c b/sys/net/if.c
index e244ce9ab819..5329c6d7ecba 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -597,46 +597,41 @@ if_slowtimo(arg)
  * interface structure pointer.
  */
 struct ifnet *
-ifunit(name)
-	register char *name;
+ifunit(char *name)
 {
 	char namebuf[IFNAMSIZ + 1];
-	register char *cp, *cp2;
-	char *end;
-	register struct ifnet *ifp;
+	char *cp;
+	struct ifnet *ifp;
 	int unit;
-	unsigned len;
-	register char c = '\0';
+	unsigned len, m;
+	char c;
 
-	/*
-	 * Look for a non numeric part
-	 */
-	end = name + IFNAMSIZ;
-	cp2 = namebuf;
-	cp = name;
-	while ((cp < end) && (c = *cp)) {
-		if (c >= '0' && c <= '9')
-			break;
-		*cp2++ = c;
-		cp++;
-	}
-	if ((cp == end) || (c == '\0') || (cp == name))
-		return ((struct ifnet *)0);
-	*cp2 = '\0';
-	/*
-	 * check we have a legal number (limit to 7 digits?)
-	 */
+	len = strlen(name);
+	if (len < 2 || len > IFNAMSIZ)
+		return NULL;
+	cp = name + len - 1;
+	c = *cp;
+	if (c < '0' || c > '9')
+		return NULL;		/* trailing garbage */
+	unit = 0;
+	m = 1;
+	do {
+		if (cp == name)
+			return NULL;	/* no interface name */
+		unit += (c - '0') * m;
+		if (unit > 1000000)
+			return NULL;	/* number is unreasonable */
+		m *= 10;
+		c = *--cp;
+	} while (c >= '0' && c <= '9');
 	len = cp - name + 1;
-	for (unit = 0;
-	    ((c = *cp) >= '0') && (c <= '9') && (unit < 1000000); cp++ )
-		unit = (unit * 10) + (c - '0');
-	if (*cp != '\0')
-		return 0;	/* no trailing garbage allowed */
+	bcopy(name, namebuf, len);
+	namebuf[len] = '\0';
 	/*
 	 * Now search all the interfaces for this name/number
 	 */
 	for (ifp = ifnet.tqh_first; ifp; ifp = ifp->if_link.tqe_next) {
-		if (bcmp(ifp->if_name, namebuf, len))
+		if (strcmp(ifp->if_name, namebuf))
 			continue;
 		if (unit == ifp->if_unit)
 			break;