typedef struct {
  CTL_NET_PORT_t this_port;
  CTL_NET_PORT_t other_port;
  CTL_NET_IPv4_ADDR_t other_ip_addr;
  void *metadata;

pointer to an instance of CTL_UDP_INFO_t is passed into user code during a UDP receive callback and out of user code when calling ctl_udp_sendto.

Note the use of ‘this’ and ‘other’ semantics rather than ‘src’ and ‘dst’.

In a UDP server, the same CTL_UDP_INFO_t pointer received in the CTL_UDP_RECV_FN_t may be passed unmodified to ctl_udp_sendto as in the following example: The simple semantic change of using "this" and "other" avoids having to do a parameter swap in the callback.

void myUdpReceiveFn(unsigned long *rcvData,
                    unsigned rcvByteCount,
                    const CTL_UDP_INFO_t *info)
  // \em{process the rcvData...}
  // \em{and then call ctl_udp_sendto}
  ctl_udp_sendto(sendData, sendByteCount, info, 0);

You can use the metaData member to store endpoint information for any application-specific data set by the MAC-layer driver.


The metaData member is intended to be used by IEEE 1588 (Precision Time Protocol)-compliant MAC layers to provide a packet timestamp (or at least a pointer to a packet timestamp), but the field may be used for any information that needs to be transmitted from the MAC layer to the application layer as part of a UDP datagram.

See Also

CTL_UDP_RECV_FN_t, ctl_udp_sendto