Hello all,
busybox 1.28.3-4 (OpenWrt 18.06.1) running on a WiFi router, requesting IP
address from 4G router (Huawei B2338-168) running in IPv4 passtrough mode. In
this mode, 4G router is assigning the the same IP address it got from ISP
(mobile network operator), lease time is 120 seconds. Because first renew
request is sent after 60 seconds, it is broadcasted (= REBINDING state);
RENEWING state is skipped:
...
case RENEWING:
if (timeout > 60) {
/* send an unicast renew request */
...
4G router drops broadcasted renew request and after lease is expired, WiFi
router releases the IP address and enters init state:
Wed Oct 3 19:02:39 2018 user.notice firewall: Reloading firewall due to ifup
of wan (eth1)
Wed Oct 3 19:03:37 2018 daemon.notice netifd: wan (1166): udhcpc: sending
renew to 0.0.0.0
Wed Oct 3 19:04:07 2018 daemon.notice netifd: wan (1166): udhcpc: sending
renew to 0.0.0.0
Wed Oct 3 19:04:22 2018 daemon.notice netifd: wan (1166): udhcpc: sending
renew to 0.0.0.0
Wed Oct 3 19:04:29 2018 daemon.notice netifd: wan (1166): udhcpc: sending
renew to 0.0.0.0
Wed Oct 3 19:04:32 2018 daemon.notice netifd: wan (1166): udhcpc: sending
renew to 0.0.0.0
Wed Oct 3 19:04:33 2018 daemon.notice netifd: wan (1166): udhcpc: sending
renew to 0.0.0.0
Wed Oct 3 19:04:33 2018 daemon.notice netifd: wan (1166): udhcpc: lease lost,
entering init state
Wed Oct 3 19:04:34 2018 daemon.notice netifd: Interface 'wan' has lost the
connection
Wed Oct 3 19:04:34 2018 daemon.notice netifd: wan (1166): udhcpc: sending
select for 10.98.21.140
Wed Oct 3 19:04:34 2018 daemon.notice netifd: wan (1166): udhcpc: lease of
10.98.21.140 obtained, lease time 120
Wed Oct 3 19:04:34 2018 daemon.err openvpn(******)[1539]: write UDP: Network
unreachable (code=128)
Wed Oct 3 19:04:34 2018 daemon.warn dnsmasq[1511]: no servers found in
/tmp/resolv.conf.auto, will retry
Wed Oct 3 19:04:35 2018 daemon.notice netifd: Interface 'wan' is now up
Wed Oct 3 19:04:35 2018 daemon.info dnsmasq[1511]: reading
/tmp/resolv.conf.auto
Wed Oct 3 19:04:35 2018 daemon.info dnsmasq[1511]: using local addresses only
for domain test
Wed Oct 3 19:04:35 2018 daemon.info dnsmasq[1511]: using local addresses only
for domain onion
Wed Oct 3 19:04:35 2018 daemon.info dnsmasq[1511]: using local addresses only
for domain localhost
Wed Oct 3 19:04:35 2018 daemon.info dnsmasq[1511]: using local addresses only
for domain local
Wed Oct 3 19:04:35 2018 daemon.info dnsmasq[1511]: using local addresses only
for domain invalid
Wed Oct 3 19:04:35 2018 daemon.info dnsmasq[1511]: using local addresses only
for domain bind
Wed Oct 3 19:04:35 2018 daemon.info dnsmasq[1511]: using nameserver
192.168.11.254#53 for domain ***
Wed Oct 3 19:04:35 2018 daemon.info dnsmasq[1511]: using local addresses only
for domain *****
Wed Oct 3 19:04:35 2018 daemon.info dnsmasq[1511]: using nameserver
160.218.161.60#53
Wed Oct 3 19:04:35 2018 daemon.info dnsmasq[1511]: using nameserver
160.218.167.5#53
Wed Oct 3 19:04:36 2018 user.notice firewall: Reloading firewall due to ifup
of wan (eth1)
So each 2 minutes wan connectivity is lost for a fraction of second.
I'd propose to perform at least one unicast renew reques irrespective of lease
time, proposed patch:
diff --git a/networking/udhcp/dhcpc.c b/networking/udhcp/dhcpc.c
index fd18325..01241ca 100644
--- a/networking/udhcp/dhcpc.c
+++ b/networking/udhcp/dhcpc.c
@@ -1414,6 +1414,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
struct dhcp_packet packet;
/* silence "uninitialized!" warning */
unsigned timestamp_before_wait = timestamp_before_wait;
+ uint32_t unicast_renew_attempt = 0;
//bb_error_msg("sockfd:%d, listen_mode:%d", sockfd,
listen_mode);
@@ -1468,6 +1469,7 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
switch (state) {
case INIT_SELECTING:
+ unicast_renew_attempt = 0;
if (!discover_retries || packet_num <
discover_retries) {
if (packet_num == 0)
xid = random_xid();
@@ -1521,8 +1523,10 @@ int udhcpc_main(int argc UNUSED_PARAM, char **argv)
case RENEW_REQUESTED: /* manual (SIGUSR1) renew */
case_RENEW_REQUESTED:
case RENEWING:
- if (timeout > 60) {
+ /* we should try to send at least one unicast
renew request */
+ if (timeout > 60 || !unicast_renew_attempt) {
/* send an unicast renew request */
+ unicast_renew_attempt = 1;
/* Sometimes observed to fail (EADDRNOTAVAIL) to bind
* a new UDP socket for sending inside send_renew.
* I hazard to guess existing listening socket
After applying patch, unicast renew request towards Huawei 4G router works as
expected:
Wed Oct 3 20:12:58 2018 daemon.notice netifd: wan (3610): udhcpc: sending
renew to 192.168.22.1
Wed Oct 3 20:12:58 2018 daemon.notice netifd: wan (3610): udhcpc: lease of
10.98.21.140 obtained, lease time 120
Wed Oct 3 20:13:58 2018 daemon.notice netifd: wan (3610): udhcpc: sending
renew to 192.168.22.1
Wed Oct 3 20:13:59 2018 daemon.notice netifd: wan (3610): udhcpc: lease of
10.98.21.140 obtained, lease time 120
Wed Oct 3 20:14:59 2018 daemon.notice netifd: wan (3610): udhcpc: sending
renew to 192.168.22.1
Wed Oct 3 20:14:59 2018 daemon.notice netifd: wan (3610): udhcpc: lease of
10.98.21.140 obtained, lease time 120
Wed Oct 3 20:16:00 2018 daemon.notice netifd: wan (3610): udhcpc: sending
renew to 192.168.22.1
Wed Oct 3 20:16:00 2018 daemon.notice netifd: wan (3610): udhcpc: lease of
10.98.21.140 obtained, lease time 120
Wed Oct 3 20:17:00 2018 daemon.notice netifd: wan (3610): udhcpc: sending
renew to 192.168.22.1
Wed Oct 3 20:17:00 2018 daemon.notice netifd: wan (3610): udhcpc: lease of
10.98.21.140 obtained, lease time 120
Thanks,
Tomas
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