[systemd-devel] [PATCH v2 24/26] dhcp: Compute expire, T1 and T2 timers
Patrik Flykt
patrik.flykt at linux.intel.com
Sun Nov 24 23:13:40 PST 2013
Compute the default T1 and T2 timer values if they were not set by
the DHCP server. Verify that the values are reasonable.
---
v2: - previous 25/28
- fix ordering of t1, t1 and expiry as suggested
- unref accepts NULL, simplify code
src/dhcp/client.c | 117 ++++++++++++++++++++++++++++++++++++++++++++++++++-
src/dhcp/protocol.h | 2 +
2 files changed, 118 insertions(+), 1 deletion(-)
diff --git a/src/dhcp/client.c b/src/dhcp/client.c
index bee1a3a..a8fb08c 100644
--- a/src/dhcp/client.c
+++ b/src/dhcp/client.c
@@ -33,6 +33,8 @@
#define DHCP_CLIENT_MIN_OPTIONS_SIZE 312
struct DHCPLease {
+ uint32_t t1;
+ uint32_t t2;
uint32_t lifetime;
uint32_t address;
uint32_t server_address;
@@ -57,6 +59,10 @@ struct DHCPClient {
uint32_t xid;
usec_t start_time;
unsigned int attempt;
+ usec_t request_sent;
+ sd_event_source *timeout_t1;
+ sd_event_source *timeout_t2;
+ sd_event_source *timeout_expire;
DHCPLease *lease;
};
@@ -156,6 +162,10 @@ static int client_stop(DHCPClient *client, int error)
client->timeout_resend = sd_event_source_unref(client->timeout_resend);
+ client->timeout_t1 = sd_event_source_unref(client->timeout_t1);
+ client->timeout_t2 = sd_event_source_unref(client->timeout_t2);
+ client->timeout_expire = sd_event_source_unref(client->timeout_expire);
+
client->attempt = 1;
switch (client->state) {
@@ -163,6 +173,7 @@ static int client_stop(DHCPClient *client, int error)
case DHCP_STATE_INIT:
case DHCP_STATE_SELECTING:
case DHCP_STATE_REQUESTING:
+ case DHCP_STATE_BOUND:
client->start_time = 0;
client->state = DHCP_STATE_INIT;
@@ -170,7 +181,6 @@ static int client_stop(DHCPClient *client, int error)
case DHCP_STATE_INIT_REBOOT:
case DHCP_STATE_REBOOTING:
- case DHCP_STATE_BOUND:
case DHCP_STATE_RENEWING:
case DHCP_STATE_REBINDING:
@@ -425,6 +435,8 @@ static int client_timeout_resend(sd_event_source *s, uint64_t usec,
if (err < 0 && client->attempt >= 64)
goto error;
+ client->request_sent = usec;
+
break;
case DHCP_STATE_INIT_REBOOT:
@@ -444,6 +456,22 @@ error:
return 0;
}
+static int client_timeout_expire(sd_event_source *s, uint64_t usec,
+ void *userdata)
+{
+ return 0;
+}
+
+static int client_timeout_t2(sd_event_source *s, uint64_t usec, void *userdata)
+{
+ return 0;
+}
+
+static int client_timeout_t1(sd_event_source *s, uint64_t usec, void *userdata)
+{
+ return 0;
+}
+
static int client_parse_offer(uint8_t code, uint8_t len, uint8_t *option,
void *user_data)
{
@@ -477,6 +505,22 @@ static int client_parse_offer(uint8_t code, uint8_t len, uint8_t *option,
memcpy(&lease->router, option, 4);
break;
+
+ case DHCP_OPTION_RENEWAL_T1_TIME:
+ if (len == 4) {
+ memcpy(&val, option, 4);
+ lease->t1 = be32toh(val);
+ }
+
+ break;
+
+ case DHCP_OPTION_REBINDING_T2_TIME:
+ if (len == 4) {
+ memcpy(&val, option, 4);
+ lease->t2 = be32toh(val);
+ }
+
+ break;
}
return 0;
@@ -604,6 +648,72 @@ error:
return r;
}
+static uint64_t client_compute_timeout(uint64_t request_sent,
+ uint32_t lifetime)
+{
+ return request_sent + (lifetime - 3) * USEC_PER_SEC +
+ + (random_u() & 0x1fffff);
+}
+
+static int client_set_lease_timeouts(DHCPClient *client, uint64_t usec)
+{
+ int err;
+ uint64_t next_timeout;
+
+ if (client->lease->lifetime < 10)
+ return -EINVAL;
+
+ if (!client->lease->t1)
+ client->lease->t1 = client->lease->lifetime / 2;
+
+ next_timeout = client_compute_timeout(client->request_sent,
+ client->lease->t1);
+ if (next_timeout < usec)
+ return -EINVAL;
+
+ err = sd_event_add_monotonic(client->event, next_timeout,
+ 10 * USEC_PER_MSEC,
+ client_timeout_t1, client,
+ &client->timeout_t1);
+ if (err < 0)
+ return err;
+
+ if (!client->lease->t2)
+ client->lease->t2 = client->lease->lifetime * 7 / 8;
+
+ if (client->lease->t2 < client->lease->t1)
+ return -EINVAL;
+
+ if (client->lease->lifetime < client->lease->t2)
+ return -EINVAL;
+
+ next_timeout = client_compute_timeout(client->request_sent,
+ client->lease->t2);
+ if (next_timeout < usec)
+ return -EINVAL;
+
+ err = sd_event_add_monotonic(client->event, next_timeout,
+ 10 * USEC_PER_MSEC,
+ client_timeout_t2, client,
+ &client->timeout_t2);
+ if (err < 0)
+ return err;
+
+ next_timeout = client_compute_timeout(client->request_sent,
+ client->lease->lifetime);
+ if (next_timeout < usec)
+ return -EINVAL;
+
+ err = sd_event_add_monotonic(client->event, next_timeout,
+ 10 * USEC_PER_MSEC,
+ client_timeout_expire, client,
+ &client->timeout_expire);
+ if (err < 0)
+ return err;
+
+ return 0;
+}
+
static int client_receive_raw_message(sd_event_source *s, int fd,
uint32_t revents, void *userdata)
{
@@ -662,6 +772,11 @@ static int client_receive_raw_message(sd_event_source *s, int fd,
client->last_addr = client->lease->address;
+ r = client_set_lease_timeouts(client,
+ now(CLOCK_MONOTONIC));
+ if (r < 0 )
+ goto error;
+
client_notify(client, DHCP_EVENT_IP_ACQUIRE);
close(client->fd);
diff --git a/src/dhcp/protocol.h b/src/dhcp/protocol.h
index f5f490d..1e59965 100644
--- a/src/dhcp/protocol.h
+++ b/src/dhcp/protocol.h
@@ -112,6 +112,8 @@ enum {
DHCP_OPTION_SERVER_IDENTIFIER = 54,
DHCP_OPTION_PARAMETER_REQUEST_LIST = 55,
DHCP_OPTION_MAXIMUM_MESSAGE_SIZE = 57,
+ DHCP_OPTION_RENEWAL_T1_TIME = 58,
+ DHCP_OPTION_REBINDING_T2_TIME = 59,
DHCP_OPTION_CLIENT_IDENTIFIER = 61,
DHCP_OPTION_END = 255,
};
--
1.7.10.4
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