1 files changed, 48 insertions, 0 deletions
diff --git a/accel-pppd/include/ipv6_dns.h b/accel-pppd/include/ipv6_dns.h
new file mode 100644
index 00000000..b604d006
--- /dev/null
+++ b/accel-pppd/include/ipv6_dns.h
@@ -0,0 +1,48 @@
+#ifndef __IPV6_DNS_H
+#define __IPV6_DNS_H
+
+#include <netinet/in.h>
+
+#include "list.h"
+#include "ipdb.h"
+#include "ap_session.h"
+
+/*
+ * Pick the IPv6 DNS servers to advertise to a session.
+ *
+ * A session may have been assigned its own servers (currently by the radius
+ * module, from the DNS-Server-IPv6-Address attribute of RFC 6911); those take
+ * precedence. Sessions without any fall back to the globally configured ones,
+ * which is what every session got before per session servers existed.
+ *
+ * Up to 'max' addresses are written to 'dns', the number written is returned.
+ * Callers advertise nothing when that is 0.
+ */
+static inline int ipv6_dns_get(const struct ap_session *ses,
+			       const struct in6_addr *conf_dns, int conf_dns_count,
+			       struct in6_addr *dns, int max)
+{
+	struct ipv6db_addr_t *a;
+	int count = 0;
+
+	if (ses && ses->ipv6_dns) {
+		list_for_each_entry(a, &ses->ipv6_dns->addr_list, entry) {
+			if (count == max)
+				break;
+			dns[count++] = a->addr;
+		}
+
+		/* An empty list means "nothing assigned", not "no DNS at all" */
+		if (count)
+			return count;
+	}
+
+	while (count < conf_dns_count && count < max) {
+		dns[count] = conf_dns[count];
+		count++;
+	}
+
+	return count;
+}
+
+#endif