Allow an SLA 0 and prefix length of 0 to delegate the whole prefix which

allows the following config:
	ia_pd 1 wm1/0

1 files changed, 15 insertions, 0 deletions

diff --git a/dhcp6.c b/dhcp6.c
index aa6d3ce4..e1e332cd 100644
--- a/dhcp6.c
+++ b/dhcp6.c
@@ -401,14 +401,29 @@ dhcp6_delegateaddr(struct in6_addr *addr, struct interface *ifp,
 	}
 
 	if (sla == NULL || sla->sla_set == 0) {
+		/* No SLA set, so make an assumption of
+		 * desired SLA and prefix length. */
 		asla.sla = ifp->index;
 		asla.prefix_len = 0;
+		asla.sla_set = 0;
+		sla = &asla;
+	} else if (sla->sla == 0 && sla->prefix_len == 0) {
+		/* An SLA of 0 was set with no prefix length specified.
+		 * This means we delegate the whole prefix. */
+		asla.sla = sla->sla;
+		asla.prefix_len = prefix->prefix_len;
+		asla.sla_set = 0;
 		sla = &asla;
 	} else if (sla->prefix_len == 0) {
+		/* An SLA was given, but prefix length was not.
+		 * We need to work out a suitable prefix length for
+		 * potentially more than one interface. */
 		asla.sla = sla->sla;
 		asla.prefix_len = 0;
+		asla.sla_set = 0;
 		sla = &asla;
 	}
+
 	if (sla->prefix_len == 0) {
 		uint32_t sla_max;
 		int bits;