zebra: support DNS configuration options in rtadv

Add support for the RDNSS and DNSSL router advertisement
options described in RFC 8106.

Signed-off-by: Lars Seipel <ls@slrz.net>

1 files changed, 51 insertions, 0 deletions

diff --git a/zebra/interface.h b/zebra/interface.h
index 01dd697772..1dbcf33fad 100644
--- a/zebra/interface.h
+++ b/zebra/interface.h
@@ -168,6 +168,22 @@ struct rtadvconf {
 	int DefaultPreference;
 #define RTADV_PREF_MEDIUM 0x0 /* Per RFC4191. */
 
+	/*
+	 * List of recursive DNS servers to include in the RDNSS option.
+	 * See [RFC8106 5.1]
+	 *
+	 * Default: empty list; do not emit RDNSS option
+	 */
+	struct list *AdvRDNSSList;
+
+	/*
+	 * List of DNS search domains to include in the DNSSL option.
+	 * See [RFC8106 5.2]
+	 *
+	 * Default: empty list; do not emit DNSSL option
+	 */
+	struct list *AdvDNSSLList;
+
 	uint8_t inFastRexmit; /* True if we're rexmits faster than usual */
 
 	/* Track if RA was configured by BGP or by the Operator or both */
@@ -182,6 +198,41 @@ struct rtadvconf {
 #define RTADV_NUM_FAST_REXMITS   4 /* Fast Rexmit RA 4 times on certain events */
 };
 
+struct rtadv_rdnss {
+	/* Address of recursive DNS server to advertise */
+	struct in6_addr addr;
+
+	/*
+	 * Lifetime in seconds; all-ones means infinity, zero
+	 * stop using it.
+	 */
+	uint32_t lifetime;
+
+	/* If lifetime not set, use a default of 3*MaxRtrAdvInterval */
+	int lifetime_set;
+};
+
+/*
+ * [RFC1035 2.3.4] sets the maximum length of a domain name (a sequence of
+ * labels, each prefixed by a length octet) at 255 octets.
+ */
+#define RTADV_MAX_ENCODED_DOMAIN_NAME 255
+
+struct rtadv_dnssl {
+	/* Domain name without trailing root zone dot (NUL-terminated) */
+	char name[RTADV_MAX_ENCODED_DOMAIN_NAME - 1];
+
+	/* Name encoded as in [RFC1035 3.1] */
+	uint8_t encoded_name[RTADV_MAX_ENCODED_DOMAIN_NAME];
+
+	/* Actual length of encoded_name */
+	size_t encoded_len;
+
+	/* Lifetime as for RDNSS */
+	uint32_t lifetime;
+	int lifetime_set;
+};
+
 #endif /* HAVE_RTADV */
 
 /* Zebra interface type - ones of interest. */