[lwip-users] [lwip] UDP questions

[Horst Garnetzke]

Hi Adam,

may I ask two questions to UDP (with sequential api):

Your documentations contains an example for
netconn_send() using netbuf_ref() function.

There is an UDP problem with using netbuf_ref() function
while sending an UDP datagram from ROM area.

code example:
   conn = netconn_new(NETCONN_UDP);
   netconn_connect(conn, ipAddrP, (u16_t) port);
   buf = netbuf_new();
   netbuf_ref(buf, datap, len);
   netconn_send(conn, buf);
   netbuf_delete(buf);
   netconn_close(conn);
   netconn_delete(conn);

netbuf_ref() sets buf->p->payload to a ROM address, but your
udp_send() calls pbuf_header(), which assumes that payload
is a address behind buf->p (it tries to decrement payload
by UDP_HLEN to insert a udp header);

I'm wrong? Is it impossible sendung UDP datagrams from
ROM without copy?


Another question:

Is it possible to send broadcast UDP datagrams to 255.255.255.255?
As understand your code, udp_send() calls ip_route(), which allows
subnet-broadcasts only?

/Horst
-- 
Horst Garnetzke                      address@hidden

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