Hi Bruno,
if (wsa->addr->sa_family == WS_AF_INET){/* When the target IPv4 address ends in 255 we must always send it as* a broadcast. Trying to send the packet without setting SO_BROADCAST* results in EACCES, to avoid that we will manually enable the flag* and send the packet, after that we will restore the disabled flag* behavior. This is the most common estimate as the broadcast address* should actually be calculated using the netmask for the interface. */
It should really be calculated using the netmask, sending a broadcast packet here is wrong if the user is not in a /24 network.