On Dec 03, 2016, at 01:05 PM, Michael Steinberg <address@hidden> wrote:
Am 03.12.2016 um 17:37 schrieb Surya Chaitanya:
Hi,
The scenario is something like this. I have created an array of say, 5 UDP PCB's.
I'd like to bind all these 5 UDP PCB's to the same local IP address and port number
combination. Isn't this posible? Like you said, if we cannot bind an IP:Port more
than one time, what is the purpose of SO_REUSE and SOF_REUSEADDR flags? Aren't they
for reusing a particular port:IP combination for several PCBs at the same time?
Thank you.
Regards,
Surya
Hello Surya,
Have a look at this nice explanation
http://stackoverflow.com/questions/14388706/socket-options-so-reuseaddr-and-so-reuseport-how-do-they-differ-do-they-mean-t
which shows in detail why those options are not meant to do what you
seem to be thinking (are you expecting some kind of load balancing?) on
standard bsd socket behaviour. I cannot tell if the intended behaviour
is different on lwip though.
LwIP implements SO_REUSEADDR and last I examined the behavior, it actually behaved like SO_REUSEPORT according to the BSD semantics (not the Linux load balancing behavior). This should allow multiple UDP binds on the same IP+ port, so I'm surprised to hear there are problems
See discussion here: http://lists.nongnu.org/archive/html/lwip-devel/2015-07/msg00017.html
Joel