Add the core of DHCPv6 client message retransmission and upper bound
timer and message count handling according to RFC 3315 Secions 7.1.2
and 14. Omit the DHCPv6 initial delay; for now it is assumed that
systemd-networkd will provide decent startup randomization that will
desynchronize the clients.
When reinitializing the client, clear all timers.
---
src/libsystemd-network/dhcp6-protocol.h | 5 ++
src/libsystemd-network/sd-dhcp6-client.c | 136 +++++++++++++++++++++++++++++++
src/systemd/sd-dhcp6-client.h | 2 +
3 files changed, 143 insertions(+)
diff --git a/src/libsystemd-network/dhcp6-protocol.h
b/src/libsystemd-network/dhcp6-protocol.h
index afe1413..442418d 100644
--- a/src/libsystemd-network/dhcp6-protocol.h
+++ b/src/libsystemd-network/dhcp6-protocol.h
@@ -41,6 +41,10 @@ enum {
DHCP6_PORT_CLIENT = 546,
};
+#define DHCP6_SOL_MAX_DELAY 1 * USEC_PER_SEC
+#define DHCP6_SOL_TIMEOUT 1 * USEC_PER_SEC
+#define DHCP6_SOL_MAX_RT 120 * USEC_PER_SEC
+
enum {
DHCP6_DUID_LLT = 1,
DHCP6_DUID_EN = 2,
@@ -51,6 +55,7 @@ enum {
enum DHCP6State {
DHCP6_STATE_STOPPED = 0,
DHCP6_STATE_RS = 1,
+ DHCP6_STATE_SOLICITATION = 2,
};
enum {
diff --git a/src/libsystemd-network/sd-dhcp6-client.c
b/src/libsystemd-network/sd-dhcp6-client.c
index f61442b..048b4ea 100644
--- a/src/libsystemd-network/sd-dhcp6-client.c
+++ b/src/libsystemd-network/sd-dhcp6-client.c
@@ -48,6 +48,10 @@ struct sd_dhcp6_client {
struct ether_addr mac_addr;
icmp6_nd *ra;
DHCP6IA ia_na;
+ usec_t retransmit_time;
+ uint8_t retransmit_count;
+ sd_event_source *timeout_resend;
+ sd_event_source *timeout_resend_expire;
sd_dhcp6_client_cb_t cb;
void *userdata;
@@ -111,6 +115,12 @@ static int client_initialize(sd_dhcp6_client *client)
client->ia_na.timeout_t2 =
sd_event_source_unref(client->ia_na.timeout_t2);
+ client->retransmit_time = 0;
+ client->retransmit_count = 0;
+ client->timeout_resend = sd_event_source_unref(client->timeout_resend);
+ client->timeout_resend_expire =
+ sd_event_source_unref(client->timeout_resend_expire);
+
client->state = DHCP6_STATE_STOPPED;
return 0;
@@ -126,6 +136,119 @@ static sd_dhcp6_client *client_stop(sd_dhcp6_client
*client, int error) {
return client;
}
+static int client_timeout_resend_expire(sd_event_source *s, uint64_t usec,
+ void *userdata) {
+ sd_dhcp6_client *client = userdata;
+
+ assert(s);
+ assert(client);
+ assert(client->event);
+
+ client_stop(client, DHCP6_EVENT_RESEND_EXPIRE);
+
+ return 0;
+}
+
+static usec_t client_timeout_compute_random(usec_t val) {
+ return val - val / 10 +
+ (random_u32() % (2 * USEC_PER_SEC)) * val / 10 / USEC_PER_SEC;
+}
+
+static int client_timeout_resend(sd_event_source *s, uint64_t usec,
+ void *userdata) {
+ int r = 0;
+ sd_dhcp6_client *client = userdata;
+ usec_t time_now, init_retransmit_time, max_retransmit_time;
+ usec_t max_retransmit_duration;
+ uint8_t max_retransmit_count;
+ char time_string[FORMAT_TIMESPAN_MAX];
+
+ assert(s);
+ assert(client);
+ assert(client->event);
+
+ client->timeout_resend = sd_event_source_unref(client->timeout_resend);
+
+ switch (client->state) {
+ case DHCP6_STATE_SOLICITATION:
+ init_retransmit_time = DHCP6_SOL_TIMEOUT;
+ max_retransmit_time = DHCP6_SOL_MAX_RT;
+ max_retransmit_count = 0;
+ max_retransmit_duration = 0;
+
+ break;
+
+ case DHCP6_STATE_STOPPED:
+ case DHCP6_STATE_RS:
+ return 0;
+ }
+
+ if (max_retransmit_count &&
+ client->retransmit_count >= max_retransmit_count) {
+ client_stop(client, DHCP6_EVENT_RETRANS_MAX);
+ return 0;
+ }
+
+ r = sd_event_now(client->event, CLOCK_MONOTONIC, &time_now);
+ if (r < 0)
+ goto error;
+
+ if (!client->retransmit_time) {
+ client->retransmit_time =
+ client_timeout_compute_random(init_retransmit_time);
+ } else {
+ if (max_retransmit_time &&
+ client->retransmit_time > max_retransmit_time / 2)
+ client->retransmit_time =
client_timeout_compute_random(max_retransmit_time);
+ else
+ client->retransmit_time =
client_timeout_compute_random(client->retransmit_time);
+ }
+
+ log_dhcp6_client(client, "Next retransmission in %s",
+ format_timespan(time_string, FORMAT_TIMESPAN_MAX,
+ client->retransmit_time, 0));
+
+ r = sd_event_add_time(client->event, &client->timeout_resend,
+ CLOCK_MONOTONIC,
+ time_now + client->retransmit_time,
+ 10 * USEC_PER_MSEC, client_timeout_resend,
+ client);
+ if (r < 0)
+ goto error;
+
+ r = sd_event_source_set_priority(client->timeout_resend,
+ client->event_priority);
+ if (r < 0)
+ goto error;
+
+ if (max_retransmit_duration && !client->timeout_resend_expire) {
+
+ log_dhcp6_client(client, "Max retransmission duration "
+ "%"PRIu64" secs",
+ max_retransmit_duration / USEC_PER_SEC);
+
+ r = sd_event_add_time(client->event,
+ &client->timeout_resend_expire,
+ CLOCK_MONOTONIC,
+ time_now + max_retransmit_duration,
+ USEC_PER_SEC,
+ client_timeout_resend_expire, client);
+ if (r < 0)
+ goto error;
+
+ r = sd_event_source_set_priority(client->timeout_resend_expire,
+ client->event_priority);
+ if (r < 0)
+ goto error;
+ }
+
+error:
+ if (r < 0)
+ client_stop(client, r);
+
+ return 0;
+}
+
static int client_ensure_iaid(sd_dhcp6_client *client) {
const char *name = NULL;
uint64_t id;
@@ -182,6 +305,19 @@ static int client_start(sd_dhcp6_client *client)
if (r < 0)
return r;
+ client->state = DHCP6_STATE_SOLICITATION;
+
+ r = sd_event_add_time(client->event, &client->timeout_resend,
+ CLOCK_MONOTONIC, 0, 0, client_timeout_resend,
+ client);
+ if (r < 0)
+ return r;
+
+ r = sd_event_source_set_priority(client->timeout_resend,
+ client->event_priority);
+ if (r < 0)
+ return r;
+
return 0;
}
diff --git a/src/systemd/sd-dhcp6-client.h b/src/systemd/sd-dhcp6-client.h
index c64ad16..3aa1af9 100644
--- a/src/systemd/sd-dhcp6-client.h
+++ b/src/systemd/sd-dhcp6-client.h
@@ -29,6 +29,8 @@
enum {
DHCP6_EVENT_STOP = 0,
DHCP6_EVENT_NO_STATEFUL_CONFIGURATION = 10,
+ DHCP6_EVENT_RESEND_EXPIRE = 11,
+ DHCP6_EVENT_RETRANS_MAX = 12,
};
typedef struct sd_dhcp6_client sd_dhcp6_client;
--
1.9.1
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