Implemented feature from RFC 6106 section '5.1. Recursive DNS Server Option':
"Lifetime 32-bit unsigned integer.
...
Hosts MAY send a Router Solicitation to ensure the RDNSS information is
fresh before the interval expires."
Host will send RS when a certain threshold of RDNSS lifetime is reached.
Values which can be adjusted:
- lifetime threshold - currently configured with a value of 80% from lifetime
- number of retries in case RA is not received - currently set to 0
- time between retries, in case RA is not received - currently set to 3 seconds
---
include/network.h | 2 +
src/network.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++
src/resolver.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++---
3 files changed, 108 insertions(+), 4 deletions(-)
diff --git a/include/network.h b/include/network.h
index 12b0621..d602683 100644
--- a/include/network.h
+++ b/include/network.h
@@ -147,6 +147,8 @@ void connman_network_set_data(struct connman_network
*network, void *data);
void connman_network_update(struct connman_network *network);
+int refresh_rs_ipv6(struct connman_network *network, int index);
+
struct connman_network_driver {
const char *name;
enum connman_network_type type;
diff --git a/src/network.c b/src/network.c
index 10f1bf3..311b3b8 100644
--- a/src/network.c
+++ b/src/network.c
@@ -28,8 +28,17 @@
#include "connman.h"
+/* How many times to retry sending RS with the purpose of
+ * refreshing RDNSS entries before they actually expire.
+ * With a value of 0, one RS will be sent, with no retries. */
+#define RS_REFRESH_RETRIES 0
+/* Value in seconds to wait for RA after RS was sent.
+ * After this time elapsed, we can send another RS. */
+#define RS_REFRESH_TIMEOUT 3
+
static GSList *network_list = NULL;
static GSList *driver_list = NULL;
+static connman_bool_t refresh_rs_in_progress = FALSE;
struct connman_network {
int refcount;
@@ -1113,6 +1122,51 @@ static void check_dhcpv6(struct nd_router_advert *reply,
connman_network_unref(network);
}
+static void receive_refresh_rs_reply(struct nd_router_advert *reply,
+ unsigned int length, void *user_data)
+{
+ struct connman_network *network = user_data;
+
+ DBG("reply %p", reply);
+
+ if (reply == NULL) {
+ /*
+ * Router solicitation message seem to get lost easily so
+ * try to send it again.
+ */
+ if (network->router_solicit_count > 0) {
+ DBG("re-send router solicitation %d",
+ network->router_solicit_count);
+ network->router_solicit_count--;
+ __connman_inet_ipv6_send_rs(network->index, 1,
+ receive_refresh_rs_reply, network);
+ return;
+ }
+ }
+
+ network->router_solicit_count = 0;
+ refresh_rs_in_progress = FALSE;
+}
+
+int refresh_rs_ipv6(struct connman_network *network, int index)
+{
+ int ret = 0;
+
+ DBG("Send RS before RDNSS entries expire");
+
+ /* Send only one RS for all RDNSS entries which are about to expire */
+ if (refresh_rs_in_progress == TRUE)
+ return 0;
+
+ refresh_rs_in_progress = TRUE;
+
+ /* Just send one RS message, without retrying */
+ network->router_solicit_count = RS_REFRESH_RETRIES;
+ ret = __connman_inet_ipv6_send_rs(index, RS_REFRESH_TIMEOUT,
+ receive_refresh_rs_reply, network);
+ return ret;
+}
+
static void autoconf_ipv6_set(struct connman_network *network)
{
struct connman_service *service;
diff --git a/src/resolver.c b/src/resolver.c
index 9656838..3a0ea3d 100644
--- a/src/resolver.c
+++ b/src/resolver.c
@@ -31,16 +31,21 @@
#include <string.h>
#include <sys/stat.h>
#include <resolv.h>
+#include <math.h>
#include "connman.h"
#define RESOLVER_FLAG_PUBLIC (1 << 0)
+/* Threshold for RDNSS lifetime. Will be used to trigger RS
+ * before RDNSS entries actually expire */
+#define RESOLVER_LIFETIME_REFRESH_THRESHOLD (0.8)
struct entry_data {
char *interface;
char *domain;
char *server;
unsigned int flags;
+ unsigned int lifetime;
guint timeout;
};
@@ -253,11 +258,41 @@ static gboolean resolver_expire_cb(gpointer user_data)
return FALSE;
}
+static gboolean resolver_refresh_cb(gpointer user_data)
+{
+ struct entry_data *entry = user_data;
+ int index;
+ unsigned int interval;
+ struct connman_service *service = NULL;
+
+ interval = ceil(entry->lifetime *
+ (1 - RESOLVER_LIFETIME_REFRESH_THRESHOLD));
+ DBG("RDNSS start lifetime timer remainder from threshold."
+ " interface %s domain %s server %s remaining lifetime %d",
+ entry->interface, entry->domain, entry->server, interval);
+
+ entry->timeout = g_timeout_add_seconds(interval,
+ resolver_expire_cb, entry);
+
+ index = connman_inet_ifindex(entry->interface);
+ if (index >= 0) {
+ service = __connman_service_lookup_from_index(index);
+ if (service != NULL) {
+ /* Send Router Solicitation to refresh RDNSS entries
+ * before their lifetime expires */
+ refresh_rs_ipv6(__connman_service_get_network(service),
+ index);
+ }
+ }
+ return FALSE;
+}
+
static int append_resolver(const char *interface, const char *domain,
const char *server, unsigned int lifetime,
unsigned int flags)
{
struct entry_data *entry;
+ unsigned int interval;
DBG("interface %s domain %s server %s lifetime %d flags %d",
interface, domain, server, lifetime, flags);
@@ -273,10 +308,16 @@ static int append_resolver(const char *interface, const
char *domain,
entry->domain = g_strdup(domain);
entry->server = g_strdup(server);
entry->flags = flags;
+ entry->lifetime = lifetime;
if (lifetime) {
int index;
- entry->timeout = g_timeout_add_seconds(lifetime,
- resolver_expire_cb, entry);
+ interval = floor(lifetime *
+ RESOLVER_LIFETIME_REFRESH_THRESHOLD);
+ DBG("RDNSS start lifetime threshold timer."
+ " interface %s domain %s server %s lifetime
threshold %d",
+ interface, domain, server, interval);
+ entry->timeout = g_timeout_add_seconds(interval,
+ resolver_refresh_cb, entry);
/*
* We update the service only for those nameservers
@@ -350,6 +391,7 @@ int connman_resolver_append_lifetime(const char *interface,
const char *domain,
const char *server, unsigned int lifetime)
{
GSList *list;
+ unsigned int interval;
DBG("interface %s domain %s server %s lifetime %d",
interface, domain, server, lifetime);
@@ -373,8 +415,14 @@ int connman_resolver_append_lifetime(const char
*interface, const char *domain,
return 0;
}
- entry->timeout = g_timeout_add_seconds(lifetime,
- resolver_expire_cb, entry);
+ interval = floor(lifetime *
+ RESOLVER_LIFETIME_REFRESH_THRESHOLD);
+ DBG("RDNSS start lifetime threshold timer."
+ " interface %s domain %s server %s lifetime
threshold %d",
+ interface, domain, server, interval);
+
+ entry->timeout = g_timeout_add_seconds(interval,
+ resolver_refresh_cb, entry);
return 0;
}
--
1.7.5.4
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