'udhcpc allows short lease to expire then attempts renew'

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List:       busybox
Subject:    udhcpc allows short lease to expire then attempts renew
From:       Paul Larkin <sinbad_4273 () yahoo ! com>
Date:       2021-04-04 13:28:28
Message-ID: 1297605853.2082581.1617542908267 () mail ! yahoo ! com
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[Attachment #2 (multipart/alternative)]

Hello,
The 2 lines below pretend that the lease is 122s when it is in fact shorter. The \
udhcp_run_script() informs the client of the actual lease time not the make believe \
one.

https://git.busybox.net/busybox/tree/networking/udhcp/dhcpc.c#n1749
A modem that gives out a temporary IP address with a 60s lease time to dd-wrt will \
see the lease time reach zero. Busybox udhcp.c will only attempt to renew after half \
the 122s make believe lease time (61s) which is after the actual lease time (60s) has \
already expired. I know nothing about DHCP but google tells me: "The client must \
renew its IP configuration data before the lease period expires." Investigating \
difficulties between a modem and dd-wrt led me to those two lines. Thanks.

[Attachment #5 (text/html)]

<html><head></head><body><div class="yahoo-style-wrap" style="font-family:Helvetica \
Neue, Helvetica, Arial, sans-serif;font-size:13px;"><div dir="ltr" \
data-setdir="false">Hello,</div><div dir="ltr" data-setdir="false"><br></div><div \
dir="ltr" data-setdir="false">The 2 lines below pretend that the lease is 122s when \
it is in fact shorter. The <span>udhcp_run_script() informs the client of the actual \
lease time not the make believe one.</span><br></div><div dir="ltr" \
data-setdir="false"><br></div><div dir="ltr" data-setdir="false"><a \
href="https://git.busybox.net/busybox/tree/networking/udhcp/dhcpc.c#n1749" \
rel="nofollow" target="_blank" \
class="">https://git.busybox.net/busybox/tree/networking/udhcp/dhcpc.c#n1749</a></div><div><br></div><div \
dir="ltr" data-setdir="false">A modem that gives out a temporary IP address with a \
60s lease time to dd-wrt will see the lease time reach zero. <span>Busybox \
udhcp.c</span> will only attempt to renew after half the 122s make believe lease time \
(61s) which is after the actual lease time (60s) has already expired.</div><div \
dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">I know \
nothing about DHCP but google tells me: "<span>The client must renew its IP \
configuration data before the lease period expires.</span>"</div><div dir="ltr" \
data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Investigating \
difficulties between a modem and dd-wrt led me to those two lines.</div><div \
dir="ltr" data-setdir="false"><br></div><div dir="ltr" \
data-setdir="false">Thanks.<br></div></div></body></html>

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