User Datagram Protocol module.

#include "lwip/opt.h"
#include "lwip/udp.h"
#include "lwip/def.h"
#include "lwip/memp.h"
#include "lwip/inet_chksum.h"
#include "lwip/ip_addr.h"
#include "lwip/netif.h"
#include "lwip/icmp.h"
#include "lwip/stats.h"
#include "lwip/snmp.h"
#include "arch/perf.h"
#include "lwip/dhcp.h"
#include <string.h>

Macros
#define	UDP_ENSURE_LOCAL_PORT_RANGE(port) (((port) & ~UDP_LOCAL_PORT_RANGE_START) + UDP_LOCAL_PORT_RANGE_START)

#define	UDP_LOCAL_PORT_RANGE_END 0xffff

#define	UDP_LOCAL_PORT_RANGE_START 0xc000

Functions
err_t	udp_bind (struct udp_pcb pcb, ip_addr_t ipaddr, u16_t port)
	Bind an UDP PCB. More...

err_t	udp_connect (struct udp_pcb pcb, ip_addr_t ipaddr, u16_t port)
	Connect an UDP PCB. More...

void	udp_disconnect (struct udp_pcb *pcb)
	Disconnect a UDP PCB. More...

void	udp_init (void)
	Initialize this module. More...

void	udp_input (struct pbuf p, struct netif inp)
	Process an incoming UDP datagram. More...

struct udp_pcb *	udp_new (void)
	Create a UDP PCB. More...

static u16_t	udp_new_port (void)
	Allocate a new local UDP port. More...

void	udp_recv (struct udp_pcb pcb, udp_recv_fn recv, void recv_arg)
	Set a receive callback for a UDP PCB. More...

void	udp_remove (struct udp_pcb *pcb)
	Remove an UDP PCB. More...

err_t	udp_send (struct udp_pcb pcb, struct pbuf p)
	Send data using UDP. More...

err_t	udp_sendto (struct udp_pcb pcb, struct pbuf p, ip_addr_t *dst_ip, u16_t dst_port)
	Send data to a specified address using UDP. More...

err_t	udp_sendto_if (struct udp_pcb pcb, struct pbuf p, ip_addr_t dst_ip, u16_t dst_port, struct netif netif)
	Send data to a specified address using UDP. More...

Variables
struct udp_pcb *	udp_pcbs

static u16_t	udp_port = UDP_LOCAL_PORT_RANGE_START

#define UDP_ENSURE_LOCAL_PORT_RANGE ( port ) (((port) & ~UDP_LOCAL_PORT_RANGE_START) + UDP_LOCAL_PORT_RANGE_START)

Referenced by udp_init().

#define UDP_LOCAL_PORT_RANGE_END 0xffff

Referenced by udp_new_port().

#define UDP_LOCAL_PORT_RANGE_START 0xc000

Referenced by udp_new_port().

err_t udp_bind	(	struct udp_pcb *	pcb,
		ip_addr_t *	ipaddr,
		u16_t	port
	)

Bind an UDP PCB.

Parameters

pcb	UDP PCB to be bound with a local address ipaddr and port.
ipaddr	local IP address to bind with. Use IP_ADDR_ANY to bind to all local interfaces.
port	local UDP port to bind with. Use 0 to automatically bind to a random port between UDP_LOCAL_PORT_RANGE_START and UDP_LOCAL_PORT_RANGE_END.

ipaddr & port are expected to be in the same byte order as in the pcb.

Returns

lwIP error code.

ERR_OK. Successful. No error occured.
ERR_USE. The specified ipaddr and port are already bound to by another UDP PCB.

See Also: udp_disconnect()

References ERR_OK, ERR_USE, ip4_addr1_16, ip4_addr2_16, ip4_addr3_16, ip4_addr4_16, ip_addr_cmp, ip_addr_debug_print, ip_addr_isany, ip_addr_set, ip_get_option, udp_pcb::local_port, LWIP_ASSERT, LWIP_DBG_STATE, LWIP_DBG_TRACE, LWIP_DEBUGF, udp_pcb::next, NULL, snmp_insert_udpidx_tree, SOF_REUSEADDR, UDP_DEBUG, udp_new_port(), and udp_pcbs.

Referenced by udp_connect().

err_t udp_connect	(	struct udp_pcb *	pcb,
		ip_addr_t *	ipaddr,
		u16_t	port
	)

Connect an UDP PCB.

This will associate the UDP PCB with the remote address.

Parameters

pcb	UDP PCB to be connected with remote address ipaddr and port.
ipaddr	remote IP address to connect with.
port	remote UDP port to connect with.

Returns: lwIP error code

ipaddr & port are expected to be in the same byte order as in the pcb.

The udp pcb is bound to a random local port if not already bound.

See Also: udp_disconnect()

TODO: this functionality belongs in upper layers

References ERR_OK, ERR_RTE, udp_pcb::flags, ip4_addr1_16, ip4_addr2_16, ip4_addr3_16, ip4_addr4_16, netif::ip_addr, ip_addr_isany, ip_addr_set, ip_route(), udp_pcb::local_port, LWIP_DBG_STATE, LWIP_DBG_TRACE, LWIP_DEBUGF, udp_pcb::next, NULL, udp_pcb::remote_port, udp_bind(), UDP_DEBUG, UDP_FLAGS_CONNECTED, udp_pcbs, and UDP_STATS_INC.

void udp_disconnect ( struct udp_pcb * pcb )

Disconnect a UDP PCB.

Parameters

pcb	the udp pcb to disconnect.

References udp_pcb::flags, ip_addr_set_any, udp_pcb::remote_port, and UDP_FLAGS_CONNECTED.

void udp_init ( void )

Initialize this module.

References UDP_ENSURE_LOCAL_PORT_RANGE, and udp_port.

Referenced by lwip_init().

void udp_input	(	struct pbuf *	p,
		struct netif *	inp
	)

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.

References current_iphdr_dest, current_iphdr_src, ERR_OK, udp_pcb::flags, icmp_dest_unreach(), ICMP_DUR_PORT, if(), inet_chksum_pseudo(), inet_chksum_pseudo_partial(), ip4_addr1_16, ip4_addr2_16, ip4_addr3_16, ip4_addr4_16, netif::ip_addr, ip_addr_cmp, ip_addr_isany, ip_addr_isbroadcast, ip_addr_ismulticast, ip_addr_netcmp, ip_current_dest_addr, ip_current_src_addr, ip_get_option, IP_PROTO_UDP, IP_PROTO_UDPLITE, IPH_HL, IPH_PROTO, iphdr, udp_pcb::local_port, LWIP_ASSERT, LWIP_DBG_LEVEL_SERIOUS, LWIP_DBG_TRACE, LWIP_DEBUGF, netif::netmask, udp_pcb::next, ntohs, NULL, pbuf::payload, pbuf_alloc(), pbuf_copy(), pbuf_free(), pbuf_header(), PBUF_RAM, PBUF_RAW, PERF_START, PERF_STOP, udp_pcb::recv, udp_pcb::recv_arg, udp_pcb::remote_port, snmp_inc_udpindatagrams, snmp_inc_udpinerrors, snmp_inc_udpnoports, SOF_BROADCAST, SOF_REUSEADDR, pbuf::tot_len, U16_F, UDP_DEBUG, udp_debug_print, UDP_FLAGS_CONNECTED, UDP_HLEN, udp_pcbs, and UDP_STATS_INC.

Referenced by ip_input().

struct udp_pcb* udp_new ( void )

Create a UDP PCB.

Returns: The UDP PCB which was created. NULL if the PCB data structure could not be allocated.

See Also: udp_remove()

References memp_malloc(), and NULL.

static u16_t udp_new_port ( void )

static

Allocate a new local UDP port.

Returns: a new (free) local UDP port number

References udp_pcb::local_port, udp_pcb::next, NULL, UDP_LOCAL_PORT_RANGE_END, UDP_LOCAL_PORT_RANGE_START, udp_pcbs, and udp_port.

Referenced by udp_bind().

void udp_recv	(	struct udp_pcb *	pcb,
		udp_recv_fn	recv,
		void *	recv_arg
	)

Set a receive callback for a UDP PCB.

This callback will be called when receiving a datagram for the pcb.

Parameters

pcb	the pcb for wich to set the recv callback
recv	function pointer of the callback function
recv_arg	additional argument to pass to the callback function

References udp_pcb::recv, and udp_pcb::recv_arg.

void udp_remove ( struct udp_pcb * pcb )

Remove an UDP PCB.

Parameters

pcb	UDP PCB to be removed. The PCB is removed from the list of UDP PCB's and the data structure is freed from memory.

See Also: udp_new()

References memp_free(), udp_pcb::next, NULL, and snmp_delete_udpidx_tree.

err_t udp_send	(	struct udp_pcb *	pcb,
		struct pbuf *	p
	)

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()

References udp_pcb::remote_port, and udp_sendto().

err_t udp_sendto	(	struct udp_pcb *	pcb,
		struct pbuf *	p,
		ip_addr_t *	dst_ip,
		u16_t	dst_port
	)

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()

Referenced by udp_send().

err_t udp_sendto_if	(	struct udp_pcb *	pcb,
		struct pbuf *	p,
		ip_addr_t *	dst_ip,
		u16_t	dst_port,
		struct netif *	netif
	)

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()

struct udp_pcb* udp_pcbs

Referenced by udp_bind(), udp_connect(), udp_input(), and udp_new_port().

u16_t udp_port = UDP_LOCAL_PORT_RANGE_START

static

Referenced by udp_init(), and udp_new_port().

Microchip® Advanced Software Framework

Macros

Functions

Variables