diff --git a/Makefile.dep b/Makefile.dep
index 0d1751434a5dad26691f472bd0f605abe2f456e9..923756103601cbfc76955bf186be2f50e95980ff 100644
--- a/Makefile.dep
+++ b/Makefile.dep
@@ -305,6 +305,10 @@ ifneq (,$(filter gnrc_ipv6_nib_6ln,$(USEMODULE)))
USEMODULE += gnrc_sixlowpan_nd
endif
+ifneq (,$(filter gnrc_ipv6_nib_dns,$(USEMODULE)))
+ USEMODULE += gnrc_ipv6_nib
+endif
+
ifneq (,$(filter gnrc_ipv6_nib_router,$(USEMODULE)))
USEMODULE += gnrc_ipv6_nib
endif
@@ -315,6 +319,9 @@ ifneq (,$(filter gnrc_ipv6_nib,$(USEMODULE)))
USEMODULE += gnrc_netif
USEMODULE += ipv6_addr
USEMODULE += random
+ ifneq (,$(filter sock_dns,$(USEMODULE)))
+ USEMODULE += gnrc_ipv6_nib_dns
+ endif
endif
ifneq (,$(filter gnrc_udp,$(USEMODULE)))
diff --git a/makefiles/pseudomodules.inc.mk b/makefiles/pseudomodules.inc.mk
index 1b4ca0337e2da2da8a556793bbfa4535b008ef00..dca9b530d0cf1e1b12ea0f8aa40f129583cae34b 100644
--- a/makefiles/pseudomodules.inc.mk
+++ b/makefiles/pseudomodules.inc.mk
@@ -17,6 +17,7 @@ PSEUDOMODULES += gnrc_ipv6_router_default
PSEUDOMODULES += gnrc_ipv6_nib_6lbr
PSEUDOMODULES += gnrc_ipv6_nib_6ln
PSEUDOMODULES += gnrc_ipv6_nib_6lr
+PSEUDOMODULES += gnrc_ipv6_nib_dns
PSEUDOMODULES += gnrc_ipv6_nib_router
PSEUDOMODULES += gnrc_netdev_default
PSEUDOMODULES += gnrc_neterr
diff --git a/sys/include/net/gnrc/ipv6/nib.h b/sys/include/net/gnrc/ipv6/nib.h
index facc9e6ccffefbb7df5fb97e373b6b0339d32fde..a3acfa906638c18b1de252168df23d542b666f42 100644
--- a/sys/include/net/gnrc/ipv6/nib.h
+++ b/sys/include/net/gnrc/ipv6/nib.h
@@ -222,6 +222,17 @@ extern "C" {
* @note Only handled with @ref GNRC_IPV6_NIB_CONF_SLAAC != 0
*/
#define GNRC_IPV6_NIB_VALID_ADDR (0x4fd2U)
+
+/**
+ * @brief Recursive DNS server timeout
+ *
+ * This message type is for the event of a recursive DNS server timeout.
+ * The expected message context is the [UDP end point](@ref sock_udp_ep_t)
+ * representing the DNS server.
+ *
+ * @note Only handled with @ref GNRC_IPV6_NIB_CONF_DNS != 0
+ */
+#define GNRC_IPV6_NIB_RDNSS_TIMEOUT (0x4fd3U)
/** @} */
/**
diff --git a/sys/include/net/gnrc/ipv6/nib/conf.h b/sys/include/net/gnrc/ipv6/nib/conf.h
index a62c4b47d0c55d77e12cf3d3c049dd286ebbc900..d859428782461a03b56fcf97c40ac8fd96f81b14 100644
--- a/sys/include/net/gnrc/ipv6/nib/conf.h
+++ b/sys/include/net/gnrc/ipv6/nib/conf.h
@@ -68,6 +68,10 @@ extern "C" {
#define GNRC_IPV6_NIB_CONF_ROUTER (1)
#endif
+#ifdef MODULE_GNRC_IPV6_NIB_DNS
+#define GNRC_IPV6_NIB_CONF_DNS (1)
+#endif
+
/**
* @name Compile flags
* @brief Compile flags to (de-)activate certain features for NIB
@@ -171,6 +175,15 @@ extern "C" {
#endif
#endif
+/**
+ * @brief Support for DNS configuration options
+ *
+ * @see [RFC 8106](https://tools.ietf.org/html/rfc8106)
+ */
+#ifndef GNRC_IPV6_NIB_CONF_DNS
+#define GNRC_IPV6_NIB_CONF_DNS (0)
+#endif
+
/**
* @brief Multihop prefix and 6LoWPAN context distribution
*
diff --git a/sys/include/net/gnrc/ndp.h b/sys/include/net/gnrc/ndp.h
index 660f47646f92e0a2ce5b4d25733b173fb4d83a48..94aff3898272265299e92624fd92d1f5ebbd7b3e 100644
--- a/sys/include/net/gnrc/ndp.h
+++ b/sys/include/net/gnrc/ndp.h
@@ -250,6 +250,29 @@ gnrc_pktsnip_t *gnrc_ndp_opt_pi_build(const ipv6_addr_t *prefix,
*/
gnrc_pktsnip_t *gnrc_ndp_opt_mtu_build(uint32_t mtu, gnrc_pktsnip_t *next);
+/**
+ * @brief Builts the recursive DNS server option
+ *
+ * @see [RFC 8106, section 5.1](https://tools.ietf.org/html/rfc8106#section-5.1)
+ * @pre `addrs != NULL`
+ * @pre `addrs_num > 0`
+ *
+ * @note Should only be used with router advertisemnents. This is not checked
+ * however, since nodes should silently ignore it in other NDP messages.
+ *
+ * @param[in] lifetime The lifetime of the recursive DNS servers
+ * @param[in] addrs The addresses of the recursive DNS servers
+ * @param[in] addrs_num The number of addresses in @p addrs
+ * @param[in] next More options in the packet. NULL, if there are none.
+ *
+ * @return The packet snip list of options, on success
+ * @return @p next, if RDNSS is not supported
+ * @return NULL, if packet buffer is full
+ */
+gnrc_pktsnip_t *gnrc_ndp_opt_rdnss_build(uint32_t lifetime, ipv6_addr_t *addrs,
+ unsigned addrs_num,
+ gnrc_pktsnip_t *next);
+
/**
* @brief Send pre-compiled neighbor solicitation depending on a given network
* interface.
diff --git a/sys/include/net/ndp.h b/sys/include/net/ndp.h
index 01f64a70366da35c8c9108e35b361daa93e7b644..97fd869511a54838269d12515d478b29cd5f99e7 100644
--- a/sys/include/net/ndp.h
+++ b/sys/include/net/ndp.h
@@ -88,6 +88,7 @@ extern "C" {
#define NDP_OPT_PI (3) /**< prefix information option */
#define NDP_OPT_RH (4) /**< redirected option */
#define NDP_OPT_MTU (5) /**< MTU option */
+#define NDP_OPT_RDNSS (25) /**< recursive DNS server option */
#define NDP_OPT_AR (33) /**< address registration option */
#define NDP_OPT_6CTX (34) /**< 6LoWPAN context option */
#define NDP_OPT_ABR (35) /**< authoritative border router option */
@@ -120,6 +121,12 @@ extern "C" {
#define NDP_OPT_MTU_LEN (1U)
/** @} */
+/**
+ * @brief Minimum length of a recursive DNS server option (in units of 8 bytes)
+ * @see [RFC 8106, section 5.1](https://tools.ietf.org/html/rfc8106#section-5.1)
+ */
+#define NDP_OPT_RDNSS_MIN_LEN (3U)
+
/**
* @{
* @name Router constants
@@ -314,6 +321,19 @@ typedef struct __attribute__((packed)) {
network_uint32_t mtu; /**< MTU */
} ndp_opt_mtu_t;
+/**
+ * @brief Recursive DNS server option format
+ * @extends ndp_opt_t
+ *
+ * @see [RFC 8106, section 5.1](https://tools.ietf.org/html/rfc8106#section-5.1)
+ */
+typedef struct __attribute__((packed)) {
+ uint8_t type; /**< option type */
+ uint8_t len; /**< length in units of 8 octets */
+ network_uint16_t resv; /**< reserved field */
+ network_uint32_t ltime; /**< lifetime in seconds */
+ ipv6_addr_t addrs[]; /**< addresses of IPv6 recursive DNS servers */
+} ndp_opt_rdnss_t;
#ifdef __cplusplus
}
diff --git a/sys/net/application_layer/dns/dns.c b/sys/net/application_layer/dns/dns.c
index ec146636cd043dcd2e061ad2b4c407fce1e958cc..adef0df244ac69ce76d12b9aaa5310c966f7f5ae 100644
--- a/sys/net/application_layer/dns/dns.c
+++ b/sys/net/application_layer/dns/dns.c
@@ -28,6 +28,9 @@
/* min domain name length is 1, so minimum record length is 7 */
#define DNS_MIN_REPLY_LEN (unsigned)(sizeof(sock_dns_hdr_t ) + 7)
+/* global DNS server UDP endpoint */
+sock_udp_ep_t sock_dns_server;
+
static ssize_t _enc_domain_name(uint8_t *out, const char *domain_name)
{
/*
@@ -132,6 +135,10 @@ int sock_dns_query(const char *domain_name, void *addr_out, int family)
uint8_t buf[SOCK_DNS_QUERYBUF_LEN];
uint8_t reply_buf[512];
+ if (sock_dns_server.port == 0) {
+ return -ECONNREFUSED;
+ }
+
if (strlen(domain_name) > SOCK_DNS_MAX_NAME_LEN) {
return -ENOSPC;
}
diff --git a/sys/net/gnrc/network_layer/ipv6/nib/_nib-router.c b/sys/net/gnrc/network_layer/ipv6/nib/_nib-router.c
index 5873b099032b996a1096439bd2e57c688c7b8502..9b2bd14bc30a4b0fa2d37f951112571d10ba4806 100644
--- a/sys/net/gnrc/network_layer/ipv6/nib/_nib-router.c
+++ b/sys/net/gnrc/network_layer/ipv6/nib/_nib-router.c
@@ -17,6 +17,9 @@
#include "net/gnrc/ndp.h"
#include "net/gnrc/netif/internal.h"
#include "net/gnrc/sixlowpan/nd.h"
+#if GNRC_IPV6_NIB_CONF_DNS
+#include "net/sock/dns.h"
+#endif
#if GNRC_IPV6_NIB_CONF_MULTIHOP_P6C
#include "_nib-6ln.h"
@@ -131,6 +134,26 @@ static gnrc_pktsnip_t *_build_ext_opts(gnrc_netif_t *netif,
_nib_offl_entry_t *pfx = NULL;
unsigned id = netif->pid;
+#if GNRC_IPV6_NIB_CONF_DNS && SOCK_HAS_IPV6
+ uint32_t rdnss_ltime = _evtimer_lookup(&sock_dns_server,
+ GNRC_IPV6_NIB_RDNSS_TIMEOUT);
+
+ if ((rdnss_ltime < UINT32_MAX) &&
+ (!ipv6_addr_is_link_local((ipv6_addr_t *)sock_dns_server.addr.ipv6))) {
+ gnrc_pktsnip_t *rdnsso = gnrc_ndp_opt_rdnss_build(
+ rdnss_ltime * MS_PER_SEC,
+ (ipv6_addr_t *)&sock_dns_server.addr,
+ 1U, ext_opts
+ );
+ if (rdnsso == NULL) {
+ /* gnrc_ndp_opt_rdnss_build() only returns NULL when pktbuf is full
+ * in this configuration */
+ DEBUG("nib: No space left in packet buffer. Not adding RDNSSO\n");
+ return NULL;
+ }
+ ext_opts = rdnsso;
+ }
+#endif /* GNRC_IPV6_NIB_CONF_DNS */
#if GNRC_IPV6_NIB_CONF_MULTIHOP_P6C
uint16_t ltime;
gnrc_pktsnip_t *abro;
diff --git a/sys/net/gnrc/network_layer/ipv6/nib/nib.c b/sys/net/gnrc/network_layer/ipv6/nib/nib.c
index 4bc923948a5680ae9a5e20942bb9204b55596208..c726827ddcd5ab02dd3e1d0f35032f806328870f 100644
--- a/sys/net/gnrc/network_layer/ipv6/nib/nib.c
+++ b/sys/net/gnrc/network_layer/ipv6/nib/nib.c
@@ -26,6 +26,9 @@
#include "net/gnrc/sixlowpan/nd.h"
#include "net/ndp.h"
#include "net/sixlowpan/nd.h"
+#if GNRC_IPV6_NIB_CONF_DNS
+#include "net/sock/dns.h"
+#endif
#include "_nib-internal.h"
#include "_nib-arsm.h"
@@ -46,6 +49,10 @@ static char addr_str[IPV6_ADDR_MAX_STR_LEN];
static gnrc_pktqueue_t _queue_pool[GNRC_IPV6_NIB_NUMOF];
#endif /* GNRC_IPV6_NIB_CONF_QUEUE_PKT */
+#if GNRC_IPV6_NIB_CONF_DNS
+static evtimer_msg_event_t _rdnss_timeout;
+#endif
+
/**
* @internal
* @{
@@ -70,6 +77,9 @@ static void _handle_rtr_timeout(_nib_dr_entry_t *router);
static void _handle_snd_na(gnrc_pktsnip_t *pkt);
/* needs to be exported for 6LN's ARO handling */
void _handle_search_rtr(gnrc_netif_t *netif);
+#if GNRC_IPV6_NIB_CONF_DNS
+static void _handle_rdnss_timeout(sock_udp_ep_t *dns_server);
+#endif
/** @} */
void gnrc_ipv6_nib_init(void)
@@ -355,6 +365,10 @@ void gnrc_ipv6_nib_handle_timer_event(void *ctx, uint16_t type)
case GNRC_IPV6_NIB_VALID_ADDR:
_handle_valid_addr(ctx);
break;
+#if GNRC_IPV6_NIB_CONF_DNS
+ case GNRC_IPV6_NIB_RDNSS_TIMEOUT:
+ _handle_rdnss_timeout(ctx);
+#endif
default:
break;
}
@@ -388,6 +402,10 @@ void gnrc_ipv6_nib_change_rtr_adv_iface(gnrc_netif_t *netif, bool enable)
*/
static void _handle_mtuo(gnrc_netif_t *netif, const icmpv6_hdr_t *icmpv6,
const ndp_opt_mtu_t *mtuo);
+#if GNRC_IPV6_NIB_CONF_DNS
+static uint32_t _handle_rdnsso(gnrc_netif_t *netif, const icmpv6_hdr_t *icmpv6,
+ const ndp_opt_rdnss_t *rdnsso);
+#endif
#if GNRC_IPV6_NIB_CONF_MULTIHOP_P6C
static uint32_t _handle_pio(gnrc_netif_t *netif, const icmpv6_hdr_t *icmpv6,
const ndp_opt_pi_t *pio,
@@ -696,6 +714,14 @@ static void _handle_rtr_adv(gnrc_netif_t *netif, const ipv6_hdr_t *ipv6,
#endif /* GNRC_IPV6_NIB_CONF_MULTIHOP_P6C */
break;
#endif /* GNRC_IPV6_NIB_CONF_6LN */
+#if GNRC_IPV6_NIB_CONF_DNS
+ case NDP_OPT_RDNSS:
+ next_timeout = _min(_handle_rdnsso(netif,
+ (icmpv6_hdr_t *)rtr_adv,
+ (ndp_opt_rdnss_t *)opt),
+ next_timeout);
+ break;
+#endif
default:
break;
}
@@ -1225,6 +1251,13 @@ void _handle_search_rtr(gnrc_netif_t *netif)
gnrc_netif_release(netif);
}
+#if GNRC_IPV6_NIB_CONF_DNS
+static void _handle_rdnss_timeout(sock_udp_ep_t *dns_server)
+{
+ memset(dns_server, 0, sizeof(sock_udp_ep_t));
+}
+#endif
+
static void _handle_mtuo(gnrc_netif_t *netif, const icmpv6_hdr_t *icmpv6,
const ndp_opt_mtu_t *mtuo)
{
@@ -1236,6 +1269,64 @@ static void _handle_mtuo(gnrc_netif_t *netif, const icmpv6_hdr_t *icmpv6,
}
}
+#if GNRC_IPV6_NIB_CONF_DNS
+static uint32_t _handle_rdnsso(gnrc_netif_t *netif, const icmpv6_hdr_t *icmpv6,
+ const ndp_opt_rdnss_t *rdnsso)
+{
+ uint32_t ltime = UINT32_MAX;
+ const ipv6_addr_t *addr;
+
+ if ((rdnsso->len < NDP_OPT_RDNSS_MIN_LEN) ||
+ (icmpv6->type != ICMPV6_RTR_ADV)) {
+ return ltime;
+ }
+ /* select first if unassigned, search possible address otherwise */
+ addr = (sock_dns_server.port == 0) ? &rdnsso->addrs[0] : NULL;
+ if (addr == NULL) {
+ unsigned addrs_num = (rdnsso->len - 1) / 2;
+ for (unsigned i = 0; i < addrs_num; i++) {
+ if (memcmp(sock_dns_server.addr.ipv6,
+ &rdnsso->addrs[i],
+ sizeof(rdnsso->addrs[i])) == 0) {
+ addr = &rdnsso->addrs[i];
+ break;
+ }
+ }
+ }
+#if SOCK_HAS_IPV6
+ ltime = byteorder_ntohl(rdnsso->ltime);
+ if (addr != NULL) {
+ if (ltime > 0) {
+ sock_dns_server.port = SOCK_DNS_PORT;
+ sock_dns_server.family = AF_INET6;
+ sock_dns_server.netif = netif->pid;
+ memcpy(sock_dns_server.addr.ipv6, rdnsso->addrs,
+ sizeof(sock_dns_server.addr.ipv6));
+
+ if (ltime < UINT32_MAX) {
+ /* the valid lifetime is given in seconds, but our timers work
+ * in milliseconds, so we have to scale down to the smallest
+ * possible value (UINT32_MAX - 1). This is however alright
+ * since we ask for a new router advertisement before this
+ * timeout expires */
+ ltime = (ltime > (UINT32_MAX / MS_PER_SEC)) ?
+ (UINT32_MAX - 1) : ltime * MS_PER_SEC;
+ _evtimer_add(&sock_dns_server, GNRC_IPV6_NIB_RDNSS_TIMEOUT,
+ &_rdnss_timeout, ltime);
+ }
+ }
+ else {
+ evtimer_del(&_nib_evtimer, &_rdnss_timeout.event);
+ _handle_rdnss_timeout(&sock_dns_server);
+ }
+ }
+#else
+ (void)addr;
+#endif
+ return ltime;
+}
+#endif
+
static void _remove_prefix(const ipv6_addr_t *pfx, unsigned pfx_len)
{
_nib_offl_entry_t *offl = NULL;
diff --git a/sys/net/gnrc/network_layer/ndp/gnrc_ndp.c b/sys/net/gnrc/network_layer/ndp/gnrc_ndp.c
index afce23dac935626f401d143f7f98385b0839bb72..e467ea9506e1542022caeccd238d99b9d1aa22ab 100644
--- a/sys/net/gnrc/network_layer/ndp/gnrc_ndp.c
+++ b/sys/net/gnrc/network_layer/ndp/gnrc_ndp.c
@@ -222,6 +222,27 @@ gnrc_pktsnip_t *gnrc_ndp_opt_mtu_build(uint32_t mtu, gnrc_pktsnip_t *next)
return pkt;
}
+gnrc_pktsnip_t *gnrc_ndp_opt_rdnss_build(uint32_t ltime, ipv6_addr_t *addrs,
+ unsigned addrs_num,
+ gnrc_pktsnip_t *next)
+{
+ assert(addrs != NULL);
+ assert(addrs_num > 0);
+ size_t opt_size = sizeof(ndp_opt_t) + (sizeof(ipv6_addr_t) * addrs_num);
+ gnrc_pktsnip_t *pkt = gnrc_ndp_opt_build(NDP_OPT_RDNSS, opt_size, next);
+
+ if (pkt != NULL) {
+ ndp_opt_rdnss_t *rdnss_opt = pkt->data;
+ rdnss_opt->resv.u16 = 0;
+ rdnss_opt->ltime = byteorder_htonl(ltime);
+ for (unsigned i = 0; i < addrs_num; i++) {
+ memcpy(&rdnss_opt->addrs[i], &addrs[i],
+ sizeof(rdnss_opt->addrs[i]));
+ }
+ }
+ return pkt;
+}
+
static gnrc_pktsnip_t *_build_headers(gnrc_netif_t *netif,
const ipv6_addr_t *src,
const ipv6_addr_t *dst,
diff --git a/tests/gnrc_sock_dns/Makefile b/tests/gnrc_sock_dns/Makefile
index a0abd781fba501da52845852163c37eaf8116058..7bdcdc41d1ee74b745b11cfd3c85718efbeb5e54 100644
--- a/tests/gnrc_sock_dns/Makefile
+++ b/tests/gnrc_sock_dns/Makefile
@@ -9,6 +9,7 @@ BOARD_INSUFFICIENT_MEMORY := chronos telosb nucleo-f042k6 nucleo-f031k6 \
USEMODULE += sock_dns
USEMODULE += gnrc_sock_udp
USEMODULE += gnrc_ipv6_default
+USEMODULE += gnrc_ipv6_nib_dns
USEMODULE += gnrc_netdev_default
USEMODULE += auto_init_gnrc_netif
diff --git a/tests/gnrc_sock_dns/main.c b/tests/gnrc_sock_dns/main.c
index 1b6cc3d22390afbdd057cfa02224a4ac117b2b43..52700febbbbf7df4ea24d63a52455056cda59aef 100644
--- a/tests/gnrc_sock_dns/main.c
+++ b/tests/gnrc_sock_dns/main.c
@@ -31,13 +31,6 @@
#define TEST_NAME "example.org"
#endif
-#ifndef DNS_SERVER
-#define DNS_SERVER "[2001:db8::1]:53"
-#endif
-
-/* global DNS server UDP endpoint */
-sock_udp_ep_t sock_dns_server;
-
/* import "ifconfig" shell command, used for printing addresses */
extern int _gnrc_netif_config(int argc, char **argv);
@@ -46,8 +39,6 @@ int main(void)
{
uint8_t addr[16] = {0};
- sock_udp_str2ep(&sock_dns_server, DNS_SERVER);
-
puts("waiting for router advertisement...");
xtimer_usleep(1U*1000000);