[lwip-members] new udp.c issue / sharing of UDP port between broadcast listeners

[leon . woestenberg]

Hello,

found another issue in recent udp.c:

udp_bind(struct udp_pcb *pcb, struct ip_addr *ipaddr, u16_t port)

does no longer allow two PCB's to share a local port.

This is what we use to mimick SO_REUSEADDR behaviour where
multiple UDP ports are allowed to listen to the same broadcast
traffic on a certain UDP port. This is allowed under *BSD/Unix/Linux
type sockets.

As said earlier, I will revert the changes made to udp.c by simply
disabling the new code using #if 0 constructs. This will probably
break some issues in the netcon_ layer once I commit.

But I rather choose the lower layer to break the upper, then vice
versa. (The lower layers must not restrict functionality needed by
upper layers.)

Regards,

Leon.