From: Roy Marples <roy@marples.name>
Date: Fri, 17 Jan 2020 16:21:37 +0000 (+0000)
Subject: inet6: Temporary addresses only work if prefix + ifidlen == 128
X-Git-Tag: v9.0.0~103
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b81f23921398ca3e736fda52c9fffea92e6cdd60;p=thirdparty%2Fdhcpcd.git

inet6: Temporary addresses only work if prefix + ifidlen == 128

Cater for various prefix lengths when using temporay addresses.
---

diff --git a/src/if-linux.c b/src/if-linux.c
index 4765a7f7..ec7b81e1 100644
--- a/src/if-linux.c
+++ b/src/if-linux.c
@@ -1802,7 +1802,8 @@ if_address6(unsigned char cmd, const struct ipv6_addr *ia)
 #endif
 		}
 #elif IFA_F_MANAGETEMPADDR
-		if (ia->flags & IPV6_AF_AUTOCONF)
+		if (ia->flags & IPV6_AF_AUTOCONF &&
+		    ipv6_ifidlen(ia->iface) + ia->prefix_len == 128)
 			flags |= IFA_F_MANAGETEMPADDR;
 #endif
 #ifdef IFA_F_NOPREFIXROUTE
diff --git a/src/ipv6.h b/src/ipv6.h
index e976bb78..3158de34 100644
--- a/src/ipv6.h
+++ b/src/ipv6.h
@@ -67,6 +67,9 @@
 #define IDGEN_RETRIES	3
 #define IDGEN_DELAY	1 /* second */
 
+/* Interface identifier length. Prefix + this == 128 for autoconf */
+#define ipv6_ifidlen(ifp)	64
+
 #ifndef IN6_ARE_MASKED_ADDR_EQUAL
 #define IN6_ARE_MASKED_ADDR_EQUAL(d, a, m)	(	\
 	(((d)->s6_addr32[0] ^ (a)->s6_addr32[0]) & (m)->s6_addr32[0]) == 0 && \
diff --git a/src/ipv6nd.c b/src/ipv6nd.c
index 10b20ed4..c652e9ae 100644
--- a/src/ipv6nd.c
+++ b/src/ipv6nd.c
@@ -1280,7 +1280,8 @@ ipv6nd_handlera(struct dhcpcd_ctx *ctx,
 #ifdef IPV6_MANAGETEMPADDR
 			/* RFC4941 Section 3.3.3 */
 			if (ap->flags & IPV6_AF_AUTOCONF &&
-			    ip6_use_tempaddr(ap->iface->name))
+			    ip6_use_tempaddr(ap->iface->name) &&
+			    ipv6_ifidlen(ap->iface) + ap->prefix_len == 128)
 			{
 				if (!new_ap) {
 					if (ipv6_settemptime(ap, 1) == NULL)