1. Put some lwip udp rx/tx relating functions to IRAM
2. Put some wifi rx/tx relating functions to IRAMa
3. Reduce wifi dynamic malloc from 4 to 1 for each ebuf
4. Update iperf example accordingly
5. Update libphy.a to v383
If destination IP address of the packet is broadcast address, firstly compare
source IP address with the that of each network interface. If it matches,
packet is forwarded from the interface.
lwip: modify dhcp timer granularity from 60s to 1s
Current DHCP granularity is 60 seconds, it's not accurate, it can cause DHCP release/rebind/renew timer
timeout at the same time, also it may renew/rebind/release at wrong time, thus cause problem.
1. modify the discover retry backoff time from (2,4,8,16,32,60,60)s to (500m,1,2,4,8,15,15)s.
2. add DHCP_DOES_ARP_CHECK to menuconfig for users to specify if do a ARP check on the offered address.
If enable, one more second will be taken in obtaining IP address.
3. update wifi libs