Currently when MAX_STATION limit in DHCP config is set to N, dhcp server
issues only N-1 IP addresses. This is problematic from customer
perspective if both SoftAP MAX_STATION and DHCP MAX_STATION limit is set
to same value. With this change DHCP server can issue N addresses that
is inline with the set limit.
Closes TW<20556>
1. "lwip_socket" should close by "lwip_close_r" other than "lwip_close"
2. for generally compatible, fix all lwip interface to normally socket interface
3. call vTaskDelete when new socket failed in case of task crash
close #https://github.com/espressif/esp32-at/issues/58
Do some refactor to socket ping:
1. Add ping_deinit to kill ping thread
2. Apply configuration set by esp_ping_set_target to socket ping
3. Limit only one ping thread
get IP address after connecting to the softap.
Now the default netif is station in station+softap mode. The UDP pcb of
DHCP server is binded to IP 0.0.0.0. When other device connects to softap, the
DHCP offer will be sent by softap.But because the destination IP of DHCP offer
is broadcast IP and the source IP of it is 0.0.0.0, it will be sent from default
netif, that is station interface. Other device can not receive the DHCP offer
sent from station interface. As a result, other device can not get IP address.
The resolution is that bind UDP pcb to the IP address of softap. So, the source
IP of DHCP offer is that of softap. DHCP offer can be sent from softap interface
by source IP route method.
Allow interfaces to be configured without a default gateway, for
local-only communication.
In case of the AP interface, if gw is not set, do not offer it.
2. Add struct station_list into tcpip_adapter layer
3. When ap -L cmd is received, get mac address from mac layer first and then search ip address based on mac address on dhcp layer.
