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udhcpc: account for script run time

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Based on the following user report:

I ran into an issue where I was seeing a long delay in the scripts called
in udhcp_run_script. I was using an old version of OpenWrt (kamikaze)
and a satellite modem. An NTP script was being called and the modem
would sometimes take a long time to respond to the DNS lookup when
it was offline.

This delay started affecting my lease time. The lease that I would
get from my satellite modem before it was online would be short:
only 60 seconds. The delay with NTP and the modem would typically
be about 18 seconds. This would cause the first DHCP renew request
from dhcpc to be a little late. Under certain circumstances,
I could even see the first DHCP renew to occur after the lease
had expired!

function                                             old     new   delta
udhcpc_main                                         2816    2837     +21

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2014-12-21 16:10:22 +01:00
parent ad0d009e0c
commit 28634924f0
1 changed files with 5 additions and 1 deletions
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6
networking/udhcp/dhcpc.c
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@ -1697,6 +1697,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
case RENEW_REQUESTED: case RENEW_REQUESTED:
case REBINDING: case REBINDING:
if (*message == DHCPACK) { if (*message == DHCPACK) {
unsigned start;
uint32_t lease_seconds; uint32_t lease_seconds;
struct in_addr temp_addr; struct in_addr temp_addr;
uint8_t *temp; uint8_t *temp;
@ -1756,7 +1757,10 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
bb_info_msg("Lease of %s obtained, lease time %u", bb_info_msg("Lease of %s obtained, lease time %u",
inet_ntoa(temp_addr), (unsigned)lease_seconds); inet_ntoa(temp_addr), (unsigned)lease_seconds);
requested_ip = packet.yiaddr; requested_ip = packet.yiaddr;
start = monotonic_sec();
udhcp_run_script(&packet, state == REQUESTING ? "bound" : "renew"); udhcp_run_script(&packet, state == REQUESTING ? "bound" : "renew");
already_waited_sec = (unsigned)monotonic_sec() - start;
state = BOUND; state = BOUND;
change_listen_mode(LISTEN_NONE); change_listen_mode(LISTEN_NONE);
@ -1774,7 +1778,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
#endif #endif
/* make future renew packets use different xid */ /* make future renew packets use different xid */
/* xid = random_xid(); ...but why bother? */ /* xid = random_xid(); ...but why bother? */
already_waited_sec = 0;
continue; /* back to main loop */ continue; /* back to main loop */
} }
if (*message == DHCPNAK) { if (*message == DHCPNAK) {