[systemd-devel] [PATCH 25/28] dhcp: Compute expire, T1 and T2 timers
Zbigniew Jędrzejewski-Szmek
zbyszek at in.waw.pl
Wed Nov 13 17:27:34 PST 2013
On Wed, Nov 13, 2013 at 11:22:53PM +0200, Patrik Flykt wrote:
> Compute the default T1 and T2 timer values if they were not set by
> the DHCP server. Verify that the values are reasonable.
> ---
> src/dhcp/client.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++++++-
> src/dhcp/protocol.h | 2 +
> 2 files changed, 124 insertions(+), 1 deletion(-)
>
> diff --git a/src/dhcp/client.c b/src/dhcp/client.c
> index 669804a..50008a9 100644
> --- a/src/dhcp/client.c
> +++ b/src/dhcp/client.c
> @@ -34,6 +34,8 @@
>
> struct DHCPLease {
> uint32_t lifetime;
> + uint32_t t2;
> + uint32_t t1;
Can we have the order t1, t2 everywhere?
> struct in_addr address;
> struct in_addr server_address;
> struct in_addr subnet_mask;
> @@ -57,6 +59,10 @@ struct DHCPClient {
> uint32_t xid;
> uint64_t start_time;
> unsigned int attempt;
> + uint64_t request_sent;
> + sd_event_source *timeout_expire;
> + sd_event_source *timeout_t1;
> + sd_event_source *timeout_t2;
> DHCPLease *lease;
> };
>
> @@ -177,6 +183,16 @@ static int client_stop(DHCPClient *client, int error)
> client->timeout_resend =
> sd_event_source_unref(client->timeout_resend);
>
> + if (client->timeout_expire)
> + client->timeout_expire =
> + sd_event_source_unref(client->timeout_expire);
sd_event_source_unref accepts NULL, so those if's are not necessary.
I think that this is not performance trical code, so it's better to
simplify.
> + if (client->timeout_t2)
> + client->timeout_t2 =
> + sd_event_source_unref(client->timeout_t2);
> + if (client->timeout_t1)
> + client->timeout_t1 =
> + sd_event_source_unref(client->timeout_t1);
> +
> client->attempt = 1;
>
> switch (client->state) {
> @@ -184,6 +200,7 @@ 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;
> @@ -191,7 +208,6 @@ 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:
>
> @@ -447,6 +463,8 @@ 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:
> @@ -466,6 +484,22 @@ 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)
> {
> @@ -499,6 +533,22 @@ static int client_parse_offer(uint8_t code, uint8_t len, uint8_t *option,
> memcpy(&lease->router.s_addr, option, 4);
>
> break;
> +
> + case DHCP_OPTION_RENEWAL_T1_TIME:
> + if (len == 4) {
> + memcpy(&val, option, 4);
> + lease->t1 = ntohl(val);
> + }
> +
> + break;
> +
> + case DHCP_OPTION_REBINDING_T2_TIME:
> + if (len == 4) {
> + memcpy(&val, option, 4);
> + lease->t2 = ntohl(val);
> + }
> +
> + break;
> }
>
> return 0;
> @@ -635,6 +685,72 @@ error:
> return err;
> }
>
> +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)
> {
> @@ -697,6 +813,11 @@ static int client_receive_raw_message(sd_event_source *s, int fd,
> client->last_addr->s_addr =
> client->lease->address.s_addr;
>
> + err = client_set_lease_timeouts(client,
> + now(CLOCK_MONOTONIC));
> + if (err < 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 6503931..773c29c 100644
> --- a/src/dhcp/protocol.h
> +++ b/src/dhcp/protocol.h
> @@ -100,5 +100,7 @@ typedef enum DHCPState DHCPState;
> #define DHCP_OPTION_SERVER_IDENTIFIER 54
> #define DHCP_OPTION_PARAMETER_REQUEST_LIST 55
> #define DHCP_OPTION_MAXIMUM_MESSAGE_SIZE 57
> +#define DHCP_OPTION_RENEWAL_T1_TIME 58
> +#define DHCP_OPTION_REBINDING_T2_TIME 59
> #define DHCP_OPTION_CLIENT_IDENTIFIER 61
> #define DHCP_OPTION_END 255
Zbyszek
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