lwip: disable ETHARP_TRUST_IP_MAC by default
Disable ETHARP_TRUST_IP_MAC by default because:
1. The LAN peer may not be trustful
2. The LAN peer may has problem to update its ARP entry
@@ -104,7 +104,7 @@ config LWIP_STATS
config LWIP_ETHARP_TRUST_IP_MAC
bool "Enable LWIP ARP trust"
- default y
+ default n
help
Enabling this option allows ARP table to be updated.
@@ -117,6 +117,17 @@ config LWIP_ETHARP_TRUST_IP_MAC
The peer *is* in the ARP table if it requested our address before.
Also notice that this slows down input processing of every IP packet!
+ There are two known issues in real application if this feature is enabled:
+ - The LAN peer may have bug to update the ARP table after the ARP entry is aged out.
+ If the ARP entry on the LAN peer is aged out but failed to be updated, all IP packets
+ sent from LWIP to the LAN peer will be dropped by LAN peer.
+ - The LAN peer may not be trustful, the LAN peer may send IP packets to LWIP with
+ two different MACs, but the same IP address. If this happens, the LWIP has problem
+ to receive IP packets from LAN peer.
+
+ So the recommendation is to disable this option.
+ Here the LAN peer means the other side to which the ESP station or soft-AP is connected.
+
config TCPIP_RECVMBOX_SIZE
int "TCPIP task receive mail box size"
default 32
