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changeset 1885:158c55bbce72 draft

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Respect xidhwaddr option for DHCPv6
author Roy Marples <roy@marples.name>
date Thu, 28 Mar 2013 06:38:27 +0000
parents 3d4a3711a436
children 23ca5addb202
files dhcp6.c
diffstat 1 files changed, 10 insertions(+), 3 deletions(-) [+]
line wrap: on
line diff
--- a/dhcp6.c	Wed Mar 27 16:36:56 2013 +0000
+++ b/dhcp6.c	Thu Mar 28 06:38:27 2013 +0000
@@ -328,11 +328,18 @@
 }
 
 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 @@
 		return -1;
 	}
 
-	dhcp6_newxid(state->send);
+	dhcp6_newxid(ifp, state->send);
 
 	o = D6_FIRST_OPTION(state->send);
 	o->code = htons(D6_OPTION_CLIENTID);