From: Roy Marples <roy@marples.name>
Date: Thu, 28 Mar 2013 06:38:27 +0000 (+0000)
Subject: Respect xidhwaddr option for DHCPv6
X-Git-Tag: v5.99.6~33
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=af1151109741d4a3faffa5f9c2e3671107ad7362;p=thirdparty%2Fdhcpcd.git

Respect xidhwaddr option for DHCPv6
---

diff --git a/dhcp6.c b/dhcp6.c
index 0679c2f0..5d09236b 100644
--- a/dhcp6.c
+++ b/dhcp6.c
@@ -328,11 +328,18 @@ dhcp6_updateelapsed(struct interface *ifp, struct dhcp6_message *m, ssize_t len)
 }
 
 static void
-dhcp6_newxid(struct dhcp6_message *m)
+dhcp6_newxid(const struct interface *ifp, struct dhcp6_message *m)
 {
 	uint32_t xid;
 
-	xid = arc4random();
+	if (ifp->options->options & DHCPCD_XID_HWADDR &&
+	    ifp->hwlen >= sizeof(xid)) 
+		/* The lower bits are probably more unique on the network */
+		memcpy(&xid, (ifp->hwaddr + ifp->hwlen) - sizeof(xid),
+		    sizeof(xid));
+	else
+		xid = arc4random();
+
 	m->xid[0] = (xid >> 16) & 0xff;
 	m->xid[1] = (xid >> 8) & 0xff;
 	m->xid[2] = xid & 0xff;
@@ -451,7 +458,7 @@ dhcp6_makemessage(struct interface *ifp)
 		return -1;
 	}
 
-	dhcp6_newxid(state->send);
+	dhcp6_newxid(ifp, state->send);
 
 	o = D6_FIRST_OPTION(state->send);
 	o->code = htons(D6_OPTION_CLIENTID);