The existing renew/rebind mechanism doesn't correctly follow the
procedure as indicated in rfc2131 section 4.4.5 dictating the
resending of renewal and rebinding packets. This change sets up
three seperate timers for T1, T2, and expiration and correctly
sends retries for renew and rebind with a logarithmic backoff.
---
gdhcp/client.c | 201 +++++++++++++++++++++++++++++++++-----------------------
1 file changed, 120 insertions(+), 81 deletions(-)
diff --git a/gdhcp/client.c b/gdhcp/client.c
index a30a19a..b59bc75 100644
--- a/gdhcp/client.c
+++ b/gdhcp/client.c
@@ -101,6 +101,9 @@ struct _GDHCPClient {
uint8_t ack_retry_times;
uint8_t conflicts;
guint timeout;
+ guint t1_timeout;
+ guint t2_timeout;
+ guint lease_timeout;
guint listener_watch;
GIOChannel *listener_channel;
GList *require_list;
@@ -272,6 +275,25 @@ static int32_t get_time_diff(struct timeval *tv)
return hsec;
}
+static void remove_timeouts(GDHCPClient *dhcp_client)
+{
+
+ if (dhcp_client->timeout > 0)
+ g_source_remove(dhcp_client->timeout);
+ if (dhcp_client->t1_timeout > 0)
+ g_source_remove(dhcp_client->t1_timeout);
+ if (dhcp_client->t2_timeout > 0)
+ g_source_remove(dhcp_client->t2_timeout);
+ if (dhcp_client->lease_timeout > 0)
+ g_source_remove(dhcp_client->lease_timeout);
+
+ dhcp_client->timeout = 0;
+ dhcp_client->t1_timeout = 0;
+ dhcp_client->t2_timeout = 0;
+ dhcp_client->lease_timeout = 0;
+
+}
+
static void add_dhcpv6_request_options(GDHCPClient *dhcp_client,
struct dhcpv6_packet *packet,
unsigned char *buf, int max_buf,
@@ -549,9 +571,7 @@ static gboolean send_announce_packet(gpointer dhcp_data)
dhcp_client->requested_ip,
dhcp_client->ifindex);
- if (dhcp_client->timeout > 0)
- g_source_remove(dhcp_client->timeout);
- dhcp_client->timeout = 0;
+ remove_timeouts(dhcp_client);
if (dhcp_client->state == IPV4LL_DEFEND) {
dhcp_client->timeout =
@@ -1327,10 +1347,7 @@ static void ipv4ll_start(GDHCPClient *dhcp_client)
guint timeout;
int seed;
- if (dhcp_client->timeout > 0) {
- g_source_remove(dhcp_client->timeout);
- dhcp_client->timeout = 0;
- }
+ remove_timeouts(dhcp_client);
switch_listening_mode(dhcp_client, L_NONE);
dhcp_client->retry_times = 0;
@@ -1356,8 +1373,7 @@ static void ipv4ll_stop(GDHCPClient *dhcp_client)
switch_listening_mode(dhcp_client, L_NONE);
- if (dhcp_client->timeout > 0)
- g_source_remove(dhcp_client->timeout);
+ remove_timeouts(dhcp_client);
if (dhcp_client->listener_watch > 0) {
g_source_remove(dhcp_client->listener_watch);
@@ -1608,10 +1624,7 @@ static void restart_dhcp(GDHCPClient *dhcp_client, int
retry_times)
{
debug(dhcp_client, "restart DHCP (retries %d)", retry_times);
- if (dhcp_client->timeout > 0) {
- g_source_remove(dhcp_client->timeout);
- dhcp_client->timeout = 0;
- }
+ remove_timeouts(dhcp_client);
dhcp_client->retry_times = retry_times;
dhcp_client->requested_ip = 0;
@@ -1621,91 +1634,105 @@ static void restart_dhcp(GDHCPClient *dhcp_client, int
retry_times)
g_dhcp_client_start(dhcp_client, dhcp_client->last_address);
}
-static gboolean start_rebound_timeout(gpointer user_data)
+static gboolean start_expire(gpointer user_data)
{
GDHCPClient *dhcp_client = user_data;
- debug(dhcp_client, "start rebound timeout");
+ debug(dhcp_client, "lease expired");
- switch_listening_mode(dhcp_client, L2);
+ /*remove all timeouts if they are set*/
+ remove_timeouts(dhcp_client);
- dhcp_client->lease_seconds >>= 1;
+ /* ip need to be cleared */
+ if (dhcp_client->lease_lost_cb)
+ dhcp_client->lease_lost_cb(dhcp_client,
+ dhcp_client->lease_lost_data);
- /* We need to have enough time to receive ACK package*/
- if (dhcp_client->lease_seconds <= 6) {
+ restart_dhcp(dhcp_client, 0);
- /* ip need to be cleared */
- if (dhcp_client->lease_lost_cb)
- dhcp_client->lease_lost_cb(dhcp_client,
- dhcp_client->lease_lost_data);
+ return false;
+}
- restart_dhcp(dhcp_client, 0);
- } else {
- send_request(dhcp_client);
+static gboolean continue_rebound(gpointer user_data)
+{
+ GDHCPClient *dhcp_client = user_data;
- dhcp_client->timeout =
- g_timeout_add_seconds_full(G_PRIORITY_HIGH,
- dhcp_client->lease_seconds >> 1,
- start_rebound_timeout,
- dhcp_client,
- NULL);
+ switch_listening_mode(dhcp_client, L2);
+ send_request(dhcp_client);
+
+ if (dhcp_client->t2_timeout> 0)
+ g_source_remove(dhcp_client->t2_timeout);
+
+ /*recalculate remaining rebind time*/
+ dhcp_client->T2 >>= 1;
+ if (dhcp_client->T2 > 60)
+ {
+ dhcp_client->t2_timeout =
+ g_timeout_add_full(G_PRIORITY_HIGH,
+ dhcp_client->T2 * 1000 + (rand() %
2000) - 1000,
+ continue_rebound,
+ dhcp_client,
+ NULL);
}
return FALSE;
}
-static void start_rebound(GDHCPClient *dhcp_client)
+static gboolean start_rebound(gpointer user_data)
{
- debug(dhcp_client, "start rebound");
+ GDHCPClient *dhcp_client = user_data;
+ /*remove renew timer*/
+ if (dhcp_client->t1_timeout > 0)
+ g_source_remove(dhcp_client->t1_timeout);
+
+ debug(dhcp_client, "start rebound");
dhcp_client->state = REBINDING;
- dhcp_client->timeout = g_timeout_add_seconds_full(G_PRIORITY_HIGH,
- dhcp_client->lease_seconds >> 1,
- start_rebound_timeout,
- dhcp_client,
- NULL);
+ /*calculate total rebind time*/
+ dhcp_client->T2 = dhcp_client->expire - dhcp_client->T2;
+
+ /*send the first rebound and reschedule*/
+ continue_rebound(user_data);
+
+ return FALSE;
}
-static gboolean start_renew_request_timeout(gpointer user_data)
+static gboolean continue_renew (gpointer user_data)
{
GDHCPClient *dhcp_client = user_data;
- debug(dhcp_client, "renew request timeout");
+ switch_listening_mode(dhcp_client, L3);
+ send_request(dhcp_client);
- if (dhcp_client->no_lease_cb)
- dhcp_client->no_lease_cb(dhcp_client,
- dhcp_client->no_lease_data);
+ if (dhcp_client->t1_timeout > 0)
+ g_source_remove(dhcp_client->t1_timeout);
- return false;
-}
+ dhcp_client->T1 >>= 1;
+
+ if (dhcp_client->T1 > 60)
+ {
+ dhcp_client->t1_timeout = g_timeout_add_full(G_PRIORITY_HIGH,
+ dhcp_client->T1 * 1000 + (rand() % 2000) - 1000,
+ continue_renew,
+ dhcp_client,
+ NULL);
+ }
-static gboolean start_renew_timeout(gpointer user_data)
+ return FALSE;
+}
+static gboolean start_renew(gpointer user_data)
{
GDHCPClient *dhcp_client = user_data;
- debug(dhcp_client, "start renew timeout");
-
+ debug(dhcp_client, "start renew");
dhcp_client->state = RENEWING;
- dhcp_client->lease_seconds >>= 1;
-
- switch_listening_mode(dhcp_client, L3);
- if (dhcp_client->lease_seconds <= 60)
- start_rebound(dhcp_client);
- else {
- send_request(dhcp_client);
+ /*calculate total renew period*/
+ dhcp_client->T1 = dhcp_client->T2 - dhcp_client->T1;
- if (dhcp_client->timeout > 0)
- g_source_remove(dhcp_client->timeout);
-
- dhcp_client->timeout =
- g_timeout_add_seconds_full(G_PRIORITY_HIGH,
- REQUEST_TIMEOUT,
- start_renew_request_timeout,
- dhcp_client,
- NULL);
- }
+ /*send first renew and reschedule for half the remaining time.*/
+ continue_renew(user_data);
return FALSE;
}
@@ -1716,12 +1743,30 @@ static void start_bound(GDHCPClient *dhcp_client)
dhcp_client->state = BOUND;
- if (dhcp_client->timeout > 0)
- g_source_remove(dhcp_client->timeout);
+ remove_timeouts(dhcp_client);
- dhcp_client->timeout = g_timeout_add_seconds_full(G_PRIORITY_HIGH,
- dhcp_client->lease_seconds >> 1,
- start_renew_timeout, dhcp_client,
+ /*
+ *TODO: T1 and T2 should be set through options instead of
+ * defaults as they are here.
+ */
+
+ dhcp_client->T1 = dhcp_client->lease_seconds >> 1;
+ dhcp_client->T2 = dhcp_client->lease_seconds * 0.875;
+ dhcp_client->expire = dhcp_client->lease_seconds;
+
+ dhcp_client->t1_timeout = g_timeout_add_seconds_full(G_PRIORITY_HIGH,
+ dhcp_client->T1,
+ start_renew, dhcp_client,
+ NULL);
+
+ dhcp_client->t2_timeout = g_timeout_add_seconds_full(G_PRIORITY_HIGH,
+ dhcp_client->T2,
+ start_rebound, dhcp_client,
+ NULL);
+
+ dhcp_client->lease_timeout= g_timeout_add_seconds_full(G_PRIORITY_HIGH,
+ dhcp_client->expire,
+ start_expire, dhcp_client,
NULL);
}
@@ -2296,7 +2341,7 @@ static gboolean listener_event(GIOChannel *channel,
GIOCondition condition,
if (*message_type != DHCPOFFER)
return TRUE;
- g_source_remove(dhcp_client->timeout);
+ remove_timeouts(dhcp_client);
dhcp_client->timeout = 0;
dhcp_client->retry_times = 0;
@@ -2316,9 +2361,7 @@ static gboolean listener_event(GIOChannel *channel,
GIOCondition condition,
if (*message_type == DHCPACK) {
dhcp_client->retry_times = 0;
- if (dhcp_client->timeout > 0)
- g_source_remove(dhcp_client->timeout);
- dhcp_client->timeout = 0;
+ remove_timeouts(dhcp_client);
dhcp_client->lease_seconds = get_lease(&packet);
@@ -2338,8 +2381,7 @@ static gboolean listener_event(GIOChannel *channel,
GIOCondition condition,
} else if (*message_type == DHCPNAK) {
dhcp_client->retry_times = 0;
- if (dhcp_client->timeout > 0)
- g_source_remove(dhcp_client->timeout);
+ remove_timeouts(dhcp_client);
dhcp_client->timeout = g_timeout_add_seconds_full(
G_PRIORITY_HIGH, 3,
@@ -2784,10 +2826,7 @@ void g_dhcp_client_stop(GDHCPClient *dhcp_client)
send_release(dhcp_client, dhcp_client->server_ip,
dhcp_client->requested_ip);
- if (dhcp_client->timeout > 0) {
- g_source_remove(dhcp_client->timeout);
- dhcp_client->timeout = 0;
- }
+ remove_timeouts(dhcp_client);
if (dhcp_client->listener_watch > 0) {
g_source_remove(dhcp_client->listener_watch);
--
1.7.9.5
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