From e1387e5d1932e27e253c85a21a3b9ac2014b1531 Mon Sep 17 00:00:00 2001
From: Jesper Skriver <jesper@FreeBSD.org>
Date: Fri, 4 May 2001 18:45:36 +0000
Subject: [PATCH] Implement slash/CIDR notation for IPv4 and IPv6 addresses.

MFC after: 1 week

Reviewed by:	phk
Obtained from:	NetBSD
---
 sbin/ifconfig/ifconfig.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/sbin/ifconfig/ifconfig.c b/sbin/ifconfig/ifconfig.c
index 6a2454fc9b34..699c433a736c 100644
--- a/sbin/ifconfig/ifconfig.c
+++ b/sbin/ifconfig/ifconfig.c
@@ -1292,6 +1292,26 @@ in_getaddr(s, which)
 	if (which != MASK)
 		sin->sin_family = AF_INET;
 
+	if (which == ADDR) {
+		char *p = NULL;
+
+		if((p = strrchr(s, '/')) != NULL) {
+			/* address is `name/masklen' */
+			int masklen;
+			int ret;
+			struct sockaddr_in *min = sintab[MASK];
+			*p = '\0';
+			ret = sscanf(p+1, "%u", &masklen);
+			if(ret != 1 || (masklen < 0 || masklen > 32)) {
+				*p = '/';
+				errx(1, "%s: bad value", s);
+			}
+			min->sin_len = sizeof(*min);
+			min->sin_addr.s_addr = htonl(~((1LL << (32 - masklen)) - 1) & 
+				              0xffffffff);
+		}
+	}
+
 	if (inet_aton(s, &sin->sin_addr))
 		return;
 	if ((hp = gethostbyname(s)) != 0)
@@ -1324,6 +1344,15 @@ in6_getaddr(s, which)
 	if (which != MASK)
 		sin->sin6_family = AF_INET6;
 
+	if (which == ADDR) {
+		char *p = NULL;
+		if((p = strrchr(s, '/')) != NULL) {
+			*p = '\0';
+			in6_getprefix(p + 1, MASK);
+			explicit_prefix = 1;
+		}
+	}
+
 	if (sin->sin6_family == AF_INET6) {
 		bzero(&hints, sizeof(struct addrinfo));
 		hints.ai_family = AF_INET6;