From: Roy Marples <roy@marples.name>
Date: Mon, 3 Nov 2014 11:58:10 +0000 (+0000)
Subject: If the IPv6 LL address is duplicated and using SLAAC private addressing,
X-Git-Tag: v6.6.1~3
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=90bd98e37daab71d177993810474790599e0495a;p=thirdparty%2Fdhcpcd.git

If the IPv6 LL address is duplicated and using SLAAC private addressing,
increament the DAD counter and get a new address.
Otherwise return a suitable error.
---

diff --git a/ipv6.c b/ipv6.c
index dc39124f..08a0972d 100644
--- a/ipv6.c
+++ b/ipv6.c
@@ -982,7 +982,7 @@ static int
 ipv6_addlinklocal(struct interface *ifp)
 {
 	struct ipv6_state *state;
-	struct ipv6_addr *ap;
+	struct ipv6_addr *ap, *ap2;
 	int dadcounter;
 
 	if (ipv6_linklocal(ifp))
@@ -1020,6 +1020,7 @@ ipv6_addlinklocal(struct interface *ifp)
 
 	if (ifp->options->options & DHCPCD_SLAACPRIVATE) {
 		dadcounter = 0;
+nextslaacprivate:
 		if (ipv6_makestableprivate(&ap->addr,
 			&ap->prefix, ap->prefix_len, ifp, &dadcounter) == -1)
 		{
@@ -1054,6 +1055,29 @@ ipv6_addlinklocal(struct interface *ifp)
 		EUI64_TO_IFID(&ap->addr);
 	}
 
+	/* Do we already have this address? */
+	TAILQ_FOREACH(ap2, &state->addrs, next) {
+		if (IN6_ARE_ADDR_EQUAL(&ap->addr, &ap2->addr)) {
+			if (ap2->addr_flags & IN6_IFF_DUPLICATED) {
+				if (ifp->options->options &
+				    DHCPCD_SLAACPRIVATE)
+				{
+					dadcounter++;
+					goto nextslaacprivate;
+				}
+				free(ap);
+				errno = EADDRNOTAVAIL;
+				return -1;
+			}
+
+			syslog(LOG_WARNING, "%s: waiting for %s to complete",
+			    ap2->iface->name, ap2->saddr);
+			free(ap);
+			errno =	EEXIST;
+			return 0;
+		}
+	}
+
 	inet_ntop(AF_INET6, &ap->addr, ap->saddr, sizeof(ap->saddr));
 	TAILQ_INSERT_TAIL(&state->addrs, ap, next);
 	ipv6_addaddr(ap);