udp.c File Reference

Process an incoming UDP datagram.

Given an incoming UDP datagram (as a chain of pbufs) this function finds a corresponding UDP PCB and hands over the pbuf to the pcbs recv function. If no pcb is found or the datagram is incorrect, the pbuf is freed.

Parameters:

p	pbuf to be demultiplexed to a UDP PCB.
inp	network interface on which the datagram was received.

Send data using UDP.

Parameters:

pcb	UDP PCB used to send the data.
p	chain of pbuf's to be sent.

The datagram will be sent to the current remote_ip & remote_port stored in pcb. If the pcb is not bound to a port, it will automatically be bound to a random port.

Returns:

lwIP error code.

• ERR_OK. Successful. No error occured.
• ERR_MEM. Out of memory.
• ERR_RTE. Could not find route to destination address.
• More errors could be returned by lower protocol layers.

See also:

udp_disconnect() udp_sendto()

Same as udp_send() but with checksum

Send data to a specified address using UDP.

Parameters:

pcb	UDP PCB used to send the data.
p	chain of pbuf's to be sent.
dst_ip	Destination IP address.
dst_port	Destination UDP port.

dst_ip & dst_port are expected to be in the same byte order as in the pcb.

If the PCB already has a remote address association, it will be restored after the data is sent.

Returns:

lwIP error code (

See also:

udp_send for possible error codes)

udp_disconnect() udp_send()

Same as udp_sendto(), but with checksum

Send data to a specified address using UDP. The netif used for sending can be specified.

This function exists mainly for DHCP, to be able to send UDP packets on a netif that is still down.

Parameters:

pcb	UDP PCB used to send the data.
p	chain of pbuf's to be sent.
dst_ip	Destination IP address.
dst_port	Destination UDP port.
netif	the netif used for sending.

dst_ip & dst_port are expected to be in the same byte order as in the pcb.

Returns:

lwIP error code (

See also:

udp_send for possible error codes)

udp_disconnect() udp_send()

Same as udp_sendto_if(), but with checksum

Definition at line 93 of file udp.c.