From: Michael Johnson <mjohnson459 at gmail.com>
To: ell at lists.01.org
Subject: Re: [PATCH] dhcp: Use bound_time for retransmission timers
Date: Fri, 13 May 2022 14:53:42 +0100 [thread overview]
Message-ID: <CACsRnHW6LNDMxhrZB-_7JAH3h3Q54D9vUqf-YJhfEg4FgBC-gA@mail.gmail.com> (raw)
In-Reply-To: 20220511172855.25992-1-denkenz@gmail.com
[-- Attachment #1: Type: text/plain, Size: 3183 bytes --]
Hi Denis,
I've been running this patch for the day and I don't think it's
actually fixed the retry. I have set a low lease time and then block
the DHCP server for the ACK and I can see that the retry still doesn't
happen.
https://pastebin.com/Gy3Gcs4W
Regards,
Michael
On Wed, 11 May 2022 at 18:29, Denis Kenzior <denkenz(a)gmail.com> wrote:
>
> start_t is used to try and calculate the retransmission timeout value
> when the client enters RENEWING or REBINDING state. This works fine on
> the first renewal since the client start timestamp and the lease bound
> timestamp are very close. Also, the RENEW request is sent immediately
> whenever the T1 timer expires and most of the time it succeeds.
>
> However, if this isn't a first renewal attempt and the RENEW request
> sent when the T1 timer expires is not successful, then the renewal
> timeout value could become too large. Fix that by using the lease
> bound_time for the retransmission timer calculation (as intended) intead
> of the client start time (start_t).
> ---
> ell/dhcp.c | 11 ++++++-----
> 1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/ell/dhcp.c b/ell/dhcp.c
> index 2d049005a135..01900f3b1d38 100644
> --- a/ell/dhcp.c
> +++ b/ell/dhcp.c
> @@ -520,6 +520,7 @@ static void dhcp_client_timeout_resend(struct l_timeout *timeout,
> void *user_data)
> {
> struct l_dhcp_client *client = user_data;
> + struct l_dhcp_lease *lease = client->lease;
> unsigned int next_timeout = 0;
> int r;
>
> @@ -555,12 +556,12 @@ static void dhcp_client_timeout_resend(struct l_timeout *timeout,
>
> switch (client->state) {
> case DHCP_STATE_RENEWING:
> - next_timeout = dhcp_rebind_renew_retry_time(client->start_t,
> - client->lease->t2);
> + next_timeout = dhcp_rebind_renew_retry_time(lease->bound_time,
> + lease->t2);
> break;
> case DHCP_STATE_REBINDING:
> - next_timeout = dhcp_rebind_renew_retry_time(client->start_t,
> - client->lease->lifetime);
> + next_timeout = dhcp_rebind_renew_retry_time(lease->bound_time,
> + lease->lifetime);
> break;
> case DHCP_STATE_REQUESTING:
> case DHCP_STATE_SELECTING:
> @@ -642,7 +643,7 @@ static void dhcp_client_t1_expired(struct l_timeout *timeout, void *user_data)
> l_timeout_set_callback(client->timeout_lease, dhcp_client_t2_expired,
> client, NULL);
>
> - next_timeout = dhcp_rebind_renew_retry_time(client->start_t,
> + next_timeout = dhcp_rebind_renew_retry_time(client->lease->bound_time,
> client->lease->t2);
> client->timeout_resend =
> l_timeout_create_ms(dhcp_fuzz_secs(next_timeout),
> --
> 2.32.0
>
next reply other threads:[~2022-05-13 13:53 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-13 13:53 Michael Johnson [this message]
-- strict thread matches above, loose matches on Subject: below --
2022-05-18 16:21 [PATCH] dhcp: Use bound_time for retransmission timers Denis Kenzior
2022-05-13 17:10 Michael Johnson
2022-05-13 16:23 Denis Kenzior
2022-05-13 15:40 Michael Johnson
2022-05-13 15:31 Michael Johnson
2022-05-13 14:30 Denis Kenzior
2022-05-11 17:28 Denis Kenzior
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