From: Antonio Huete Jimenez <tuxillo@quantumachine.net>
Date: Thu, 7 Aug 2014 07:47:01 +0000 (+0200)
Subject: dhclient - Refuse leases for already configured subnets.
X-Git-Url: https://gitweb.dragonflybsd.org/~nant/dragonfly.git/commitdiff_plain/107428a4d66c180d28fe25176b90c1da4d9dabc7

dhclient - Refuse leases for already configured subnets.

Taken-from: OpenBSD
---

diff --git a/sbin/dhclient/dhclient.c b/sbin/dhclient/dhclient.c
index 12a7677b4e..9db5f4bdc6 100644
--- a/sbin/dhclient/dhclient.c
+++ b/sbin/dhclient/dhclient.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: src/sbin/dhclient/dhclient.c,v 1.155 2012/09/17 20:30:17 krw Exp $	*/
+/*	$OpenBSD: src/sbin/dhclient/dhclient.c,v 1.156 2012/09/18 09:34:09 krw Exp $	*/
 
 /*
  * Copyright 2004 Henning Brauer <henning@openbsd.org>
@@ -743,6 +743,13 @@ dhcpoffer(struct iaddr client_addr, struct option_data *options)
 		return;
 	}
 
+	/*
+	 * Reject offers whose subnet is already configured on another
+	 * interface.
+	 */
+	if (subnet_exists(lease))
+		return;
+
 	/* If this lease was acquired through a BOOTREPLY, record that
 	   fact. */
 	if (!options[DHO_DHCP_MESSAGE_TYPE].len)
diff --git a/sbin/dhclient/dhcpd.h b/sbin/dhclient/dhcpd.h
index 4c65a11291..5a77e8dd69 100644
--- a/sbin/dhclient/dhcpd.h
+++ b/sbin/dhclient/dhcpd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: src/sbin/dhclient/dhcpd.h,v 1.80 2012/09/01 19:08:42 krw Exp $	*/
+/*	$OpenBSD: src/sbin/dhclient/dhcpd.h,v 1.81 2012/09/18 09:34:09 krw Exp $	*/
 
 /*
  * Copyright (c) 2004 Henning Brauer <henning@openbsd.org>
@@ -253,6 +253,7 @@ void set_timeout_interval(time_t, void (*)(void));
 void cancel_timeout(void);
 int interface_status(char *);
 int interface_link_forceup(char *);
+int subnet_exists(struct client_lease *);
 
 /* tables.c */
 extern const struct option dhcp_options[256];
diff --git a/sbin/dhclient/dispatch.c b/sbin/dhclient/dispatch.c
index a5e7622909..27869ebf9e 100644
--- a/sbin/dhclient/dispatch.c
+++ b/sbin/dhclient/dispatch.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: src/sbin/dhclient/dispatch.c,v 1.57 2012/09/17 12:10:46 krw Exp $	*/
+/*	$OpenBSD: src/sbin/dhclient/dispatch.c,v 1.58 2012/09/18 09:34:09 krw Exp $	*/
 
 /*
  * Copyright 2004 Henning Brauer <henning@openbsd.org>
@@ -312,3 +312,52 @@ cancel_timeout(void)
 	timeout.when = 0;
 	timeout.func = NULL;
 }
+
+int
+subnet_exists(struct client_lease *l)
+{
+	struct ifaddrs *ifap, *ifa;
+	in_addr_t mymask, myaddr, mynet, hismask, hisaddr, hisnet;
+
+	bcopy(l->options[DHO_SUBNET_MASK].data, &mymask, 4);
+	bcopy(l->address.iabuf, &myaddr, 4);
+	mynet = mymask & myaddr;
+
+	if (getifaddrs(&ifap) != 0)
+		error("getifaddrs failed");
+
+	for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
+		if (strcmp(ifi->name, ifa->ifa_name) == 0)
+			continue;
+
+		if (ifa->ifa_addr->sa_family != AF_INET)
+			continue;
+
+		hismask = ((struct sockaddr_in *)ifa->ifa_netmask)->
+		    sin_addr.s_addr;
+		hisaddr = ((struct sockaddr_in *)ifa->ifa_addr)->
+		    sin_addr.s_addr;
+		hisnet = hisaddr & hismask;
+
+		if (hisnet == 0)
+			continue;
+
+		/* Would his packets go out *my* interface? */
+		if (mynet == (hisaddr & mymask)) {
+			note("interface %s already has the offered subnet!",
+			    ifa->ifa_name);
+			return (1);
+		}
+		
+		/* Would my packets go out *his* interface? */
+		if (hisnet == (myaddr & hismask)) {
+			note("interface %s already has the offered subnet!",
+			    ifa->ifa_name);
+			return (1);
+		}
+	}
+
+	freeifaddrs(ifap);
+
+	return (0);
+}