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Using typedefs for function prototypes and -pointers throughout the stack for clarity

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This commit is contained in:
goldsimon
2010-01-14 20:02:15 +00:00
parent b463562241
commit 2d4e76874c
15 changed files with 245 additions and 184 deletions
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62
src/include/lwip/netif.h
View File

@@ -81,10 +81,45 @@ extern "C" {
/** if set, the netif has IGMP capability */
#define NETIF_FLAG_IGMP 0x40U
/** Function prototype for netif init functions. Set up flags and output/linkoutput
* callback functions in this function.
*
* @param netif The netif to initialize
*/
typedef err_t (*netif_init_fn)(struct netif *netif);
/** Function prototype for netif->input functions. This function is saved as 'input'
* callback function in the netif struct. Call it when a packet has been received.
*
* @param p The received packet, copied into a pbuf
* @param inp The netif which received the packet
*/
typedef err_t (*netif_input_fn)(struct pbuf *p, struct netif *inp);
/** Function prototype for netif->output functions. Called by lwIP when a packet
* shall be sent. For ethernet netif, set this to 'etharp_output' and set
* 'linkoutput'.
*
* @param netif The netif which shall send a packet
* @param p The packet to send (p->payload points to IP header)
* @param ipaddr The IP address to which the packet shall be sent
*/
typedef err_t (*netif_output_fn)(struct netif *netif, struct pbuf *p,
struct ip_addr *ipaddr);
/** Function prototype for netif->linkoutput functions. Only used for ethernet
* netifs. This function is called by ARP when a packet shall be sent.
*
* @param netif The netif which shall send a packet
* @param p The packet to send (raw ethernet packet)
*/
typedef err_t (*netif_linkoutput_fn)(struct netif *netif, struct pbuf *p);
/** Function prototype for netif status- or link-callback functions. */
typedef void (*netif_status_callback_fn)(struct netif *netif);
/** Function prototype for netif igmp_mac_filter functions */
typedef err_t (*netif_igmp_mac_filter_fn)(struct netif *netif,
struct ip_addr *group, u8_t action);
/** Generic data structure used for all lwIP network interfaces.
* The following fields should be filled in by the initialization
* function for the device driver: hwaddr_len, hwaddr[], mtu, flags */
struct netif {
/** pointer to next in linked list */
struct netif *next;
@@ -96,25 +131,24 @@ struct netif {
/** This function is called by the network device driver
* to pass a packet up the TCP/IP stack. */
err_t (* input)(struct pbuf *p, struct netif *inp);
netif_input_fn input;
/** This function is called by the IP module when it wants
* to send a packet on the interface. This function typically
* first resolves the hardware address, then sends the packet. */
err_t (* output)(struct netif *netif, struct pbuf *p,
struct ip_addr *ipaddr);
netif_output_fn output;
/** This function is called by the ARP module when it wants
* to send a packet on the interface. This function outputs
* the pbuf as-is on the link medium. */
err_t (* linkoutput)(struct netif *netif, struct pbuf *p);
netif_linkoutput_fn linkoutput;
#if LWIP_NETIF_STATUS_CALLBACK
/** This function is called when the netif state is set to up or down
*/
void (* status_callback)(struct netif *netif);
netif_status_callback_fn status_callback;
#endif /* LWIP_NETIF_STATUS_CALLBACK */
#if LWIP_NETIF_LINK_CALLBACK
/** This function is called when the netif link is set to up or down
*/
void (* link_callback)(struct netif *netif);
netif_status_callback_fn link_callback;
#endif /* LWIP_NETIF_LINK_CALLBACK */
/** This field can be set by the device driver and could point
* to state information for the device. */
@@ -161,8 +195,9 @@ struct netif {
u32_t ifoutdiscards;
#endif /* LWIP_SNMP */
#if LWIP_IGMP
/* This function could be called to add or delete a entry in the multicast filter table of the ethernet MAC.*/
err_t (*igmp_mac_filter)(struct netif *netif, struct ip_addr *group, u8_t action);
/** This function could be called to add or delete a entry in the multicast
filter table of the ethernet MAC.*/
netif_igmp_mac_filter_fn igmp_mac_filter;
#endif /* LWIP_IGMP */
#if LWIP_NETIF_HWADDRHINT
u8_t *addr_hint;
@@ -205,10 +240,7 @@ extern struct netif *netif_default;
#define netif_init() /* Compatibility define, no init needed. */
struct netif *netif_add(struct netif *netif, struct ip_addr *ipaddr, struct ip_addr *netmask,
struct ip_addr *gw,
void *state,
err_t (* init)(struct netif *netif),
err_t (* input)(struct pbuf *p, struct netif *netif));
struct ip_addr *gw, void *state, netif_init_fn init, netif_input_fn input);
void
netif_set_addr(struct netif *netif,struct ip_addr *ipaddr, struct ip_addr *netmask,
@@ -236,7 +268,7 @@ void netif_set_down(struct netif *netif);
/*
* Set callback to be called when interface is brought up/down
*/
void netif_set_status_callback(struct netif *netif, void (* status_callback)(struct netif *netif));
void netif_set_status_callback(struct netif *netif, netif_status_callback_fn status_callback);
#endif /* LWIP_NETIF_STATUS_CALLBACK */
#if LWIP_NETIF_LINK_CALLBACK
@@ -245,7 +277,7 @@ void netif_set_link_down(struct netif *netif);
/** Ask if a link is up */
#define netif_is_link_up(netif) (((netif)->flags & NETIF_FLAG_LINK_UP) ? (u8_t)1 : (u8_t)0)
void netif_set_link_callback(struct netif *netif, void (* link_callback)(struct netif *netif));
void netif_set_link_callback(struct netif *netif, netif_status_callback_fn link_callback);
#endif /* LWIP_NETIF_LINK_CALLBACK */
#if ENABLE_LOOPBACK

19
src/include/lwip/netifapi.h
View File

@@ -41,6 +41,9 @@
extern "C" {
#endif
typedef void (*netifapi_void_fn)(struct netif *netif);
typedef err_t (*netifapi_errt_fn)(struct netif *netif);
struct netifapi_msg_msg {
#if !LWIP_TCPIP_CORE_LOCKING
sys_sem_t sem;
@@ -53,12 +56,12 @@ struct netifapi_msg_msg {
struct ip_addr *netmask;
struct ip_addr *gw;
void *state;
err_t (* init) (struct netif *netif);
err_t (* input)(struct pbuf *p, struct netif *netif);
netif_init_fn init;
netif_input_fn input;
} add;
struct {
void (* voidfunc)(struct netif *netif);
err_t (* errtfunc)(struct netif *netif);
netifapi_void_fn voidfunc;
netifapi_errt_fn errtfunc;
} common;
} msg;
};
@@ -75,8 +78,8 @@ err_t netifapi_netif_add ( struct netif *netif,
struct ip_addr *netmask,
struct ip_addr *gw,
void *state,
err_t (* init)(struct netif *netif),
err_t (* input)(struct pbuf *p, struct netif *netif) );
netif_init_fn init,
netif_input_fn input);
err_t netifapi_netif_set_addr ( struct netif *netif,
struct ip_addr *ipaddr,
@@ -84,8 +87,8 @@ err_t netifapi_netif_set_addr ( struct netif *netif,
struct ip_addr *gw );
err_t netifapi_netif_common ( struct netif *netif,
void (* voidfunc)(struct netif *netif),
err_t (* errtfunc)(struct netif *netif) );
netifapi_void_fn voidfunc,
netifapi_errt_fn errtfunc);
#define netifapi_netif_remove(n) netifapi_netif_common(n, netif_remove, NULL)
#define netifapi_netif_set_up(n) netifapi_netif_common(n, netif_set_up, NULL)

37
src/include/lwip/raw.h
View File

@@ -45,26 +45,31 @@
extern "C" {
#endif
struct raw_pcb;
/** Function prototype for raw pcb receive callback functions.
* @param arg user supplied argument (raw_pcb.recv_arg)
* @param pcb the raw_pcb which received data
* @param p the packet buffer that was received
* @param addr the remote IP address from which the packet was received
* @return 1 if the packet was 'eaten' (aka. deleted),
* 0 if the packet lives on
* If returning 1, the callback is responsible for freeing the pbuf
* if it's not used any more.
*/
typedef u8_t (*raw_recv_fn)(void *arg, struct raw_pcb *pcb, struct pbuf *p,
struct ip_addr *addr);
struct raw_pcb {
/* Common members of all PCB types */
/* Common members of all PCB types */
IP_PCB;
struct raw_pcb *next;
u8_t protocol;
/* receive callback function
* @param arg user supplied argument (raw_pcb.recv_arg)
* @param pcb the raw_pcb which received data
* @param p the packet buffer that was received
* @param addr the remote IP address from which the packet was received
* @return 1 if the packet was 'eaten' (aka. deleted),
* 0 if the packet lives on
* If returning 1, the callback is responsible for freeing the pbuf
* if it's not used any more.
*/
u8_t (* recv)(void *arg, struct raw_pcb *pcb, struct pbuf *p,
struct ip_addr *addr);
/** receive callback function */
raw_recv_fn recv;
/* user-supplied argument for the recv callback */
void *recv_arg;
};
@@ -76,11 +81,7 @@ void raw_remove (struct raw_pcb *pcb);
err_t raw_bind (struct raw_pcb *pcb, struct ip_addr *ipaddr);
err_t raw_connect (struct raw_pcb *pcb, struct ip_addr *ipaddr);
void raw_recv (struct raw_pcb *pcb,
u8_t (* recv)(void *arg, struct raw_pcb *pcb,
struct pbuf *p,
struct ip_addr *addr),
void *recv_arg);
void raw_recv (struct raw_pcb *pcb, raw_recv_fn recv, void *recv_arg);
err_t raw_sendto (struct raw_pcb *pcb, struct pbuf *p, struct ip_addr *ipaddr);
err_t raw_send (struct raw_pcb *pcb, struct pbuf *p);

5
src/include/lwip/sys.h
View File

@@ -75,6 +75,9 @@ typedef u8_t sys_mbox_t;
#include "lwip/err.h"
#include "arch/sys_arch.h"
/** Function prototype for thread functions */
typedef void (*lwip_thread_fn)(void *arg);
/* Semaphore functions. */
sys_sem_t sys_sem_new(u8_t count);
void sys_sem_signal(sys_sem_t sem);
@@ -103,7 +106,7 @@ void sys_mbox_free(sys_mbox_t mbox);
#define sys_mbox_fetch(mbox, msg) sys_arch_mbox_fetch(mbox, msg, 0)
/* Thread functions. */
sys_thread_t sys_thread_new(char *name, void (* thread)(void *arg), void *arg, int stacksize, int prio);
sys_thread_t sys_thread_new(char *name, lwip_thread_fn thread, void *arg, int stacksize, int prio);
#endif /* NO_SYS */

143
src/include/lwip/tcp.h
View File

@@ -49,6 +49,71 @@ extern "C" {
struct tcp_pcb;
/** Function prototype for tcp accept callback functions. Called when a new
* connection can be accepted on a listening pcb.
*
* @param arg Additional argument to pass to the callback function (@see tcp_arg())
* @param newpcb The new connection pcb
* @param err An error code if there has been an error accepting
*/
typedef err_t (*tcp_accept_fn)(void *arg, struct tcp_pcb *newpcb, err_t err);
/** Function prototype for tcp receive callback functions. Called when data has
* been received.
*
* @param arg Additional argument to pass to the callback function (@see tcp_arg())
* @param tpcb The connection pcb which received data
* @param p The received data (or NULL when the connection has been closed!)
* @param err An error code if there has been an error receiving
*/
typedef err_t (*tcp_recv_fn)(void *arg, struct tcp_pcb *tpcb,
struct pbuf *p, err_t err);
/** Function prototype for tcp sent callback functions. Called when sent data has
* been acknowledged by the remote side. Use it to free corresponding resources.
* This also means that the pcb has now space available to send new data.
*
* @param arg Additional argument to pass to the callback function (@see tcp_arg())
* @param tpcb The connection pcb for which data has been acknowledged
* @param len The amount of bytes acknowledged
* @return ERR_OK: try to send some data by calling tcp_output
*/
typedef err_t (*tcp_sent_fn)(void *arg, struct tcp_pcb *tpcb,
u16_t len);
/** Function prototype for tcp poll callback functions. Called periodically as
* specified by @see tcp_poll.
*
* @param arg Additional argument to pass to the callback function (@see tcp_arg())
* @param tpcb tcp pcb
* @return ERR_OK: try to send some data by calling tcp_output
*/
typedef err_t (*tcp_poll_fn)(void *arg, struct tcp_pcb *tpcb);
/** Function prototype for tcp error callback functions. Called when the pcb
* receives a RST or is unexpectedly closed for any other reason.
*
* @note The corresponding pcb is already freed when this callback is called!
*
* @param arg Additional argument to pass to the callback function (@see tcp_arg())
* @param err Error code to indicate why the pcb has been closed
* ERR_ABRT: aborted through tcp_abort or by a TCP timer
* ERR_RST: the connection was reset by the remote host
*/
typedef void (*tcp_err_fn)(void *arg, err_t err);
/** Function prototype for tcp connected callback functions. Called when a pcb
* is connected to the remote side after initiating a connection attempt by
* calling tcp_connect().
*
* @param arg Additional argument to pass to the callback function (@see tcp_arg())
* @param tpcb The connection pcb which is connected
* @param err An unused error code, always ERR_OK currently ;-) TODO!
*
* @note When a connection attempt fails, the error callback is currently called!
*/
typedef err_t (*tcp_connected_fn)(void *arg, struct tcp_pcb *tpcb, err_t err);
/* Functions for interfacing with TCP: */
/* Lower layer interface to TCP: */
@@ -61,20 +126,11 @@ struct tcp_pcb * tcp_new (void);
struct tcp_pcb * tcp_alloc (u8_t prio);
void tcp_arg (struct tcp_pcb *pcb, void *arg);
void tcp_accept (struct tcp_pcb *pcb,
err_t (* accept)(void *arg, struct tcp_pcb *newpcb,
err_t err));
void tcp_recv (struct tcp_pcb *pcb,
err_t (* recv)(void *arg, struct tcp_pcb *tpcb,
struct pbuf *p, err_t err));
void tcp_sent (struct tcp_pcb *pcb,
err_t (* sent)(void *arg, struct tcp_pcb *tpcb,
u16_t len));
void tcp_poll (struct tcp_pcb *pcb,
err_t (* poll)(void *arg, struct tcp_pcb *tpcb),
u8_t interval);
void tcp_err (struct tcp_pcb *pcb,
void (* err)(void *arg, err_t err));
void tcp_accept (struct tcp_pcb *pcb, tcp_accept_fn accept);
void tcp_recv (struct tcp_pcb *pcb, tcp_recv_fn recv);
void tcp_sent (struct tcp_pcb *pcb, tcp_sent_fn sent);
void tcp_poll (struct tcp_pcb *pcb, tcp_poll_fn poll, u8_t interval);
void tcp_err (struct tcp_pcb *pcb, tcp_err_fn err);
#define tcp_mss(pcb) ((pcb)->mss)
#define tcp_sndbuf(pcb) ((pcb)->snd_buf)
@@ -92,9 +148,7 @@ void tcp_recved (struct tcp_pcb *pcb, u16_t len);
err_t tcp_bind (struct tcp_pcb *pcb, struct ip_addr *ipaddr,
u16_t port);
err_t tcp_connect (struct tcp_pcb *pcb, struct ip_addr *ipaddr,
u16_t port, err_t (* connected)(void *arg,
struct tcp_pcb *tpcb,
err_t err));
u16_t port, tcp_connected_fn connected);
struct tcp_pcb * tcp_listen_with_backlog(struct tcp_pcb *pcb, u8_t backlog);
#define tcp_listen(pcb) tcp_listen_with_backlog(pcb, TCP_DEFAULT_LISTEN_BACKLOG)
@@ -271,7 +325,7 @@ enum tcp_state {
* @return ERR_OK: accept the new connection,
* any other err_t abortsthe new connection
*/
#define DEF_ACCEPT_CALLBACK err_t (* accept)(void *arg, struct tcp_pcb *newpcb, err_t err)
#define DEF_ACCEPT_CALLBACK tcp_accept_fn accept
#else /* LWIP_CALLBACK_API */
#define DEF_ACCEPT_CALLBACK
#endif /* LWIP_CALLBACK_API */
@@ -366,49 +420,16 @@ struct tcp_pcb {
struct pbuf *refused_data; /* Data previously received but not yet taken by upper layer */
#if LWIP_CALLBACK_API
/* Function to be called when more send buffer space is available.
* @param arg user-supplied argument (tcp_pcb.callback_arg)
* @param pcb the tcp_pcb which has send buffer space available
* @param space the amount of bytes available
* @return ERR_OK: try to send some data by calling tcp_output
*/
err_t (* sent)(void *arg, struct tcp_pcb *pcb, u16_t space);
/* Function to be called when (in-sequence) data has arrived.
* @param arg user-supplied argument (tcp_pcb.callback_arg)
* @param pcb the tcp_pcb for which data has arrived
* @param p the packet buffer which arrived
* @param err an error argument (TODO: that is current always ERR_OK?)
* @return ERR_OK: try to send some data by calling tcp_output
*/
err_t (* recv)(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);
/* Function to be called when a connection has been set up.
* @param arg user-supplied argument (tcp_pcb.callback_arg)
* @param pcb the tcp_pcb that now is connected
* @param err an error argument (TODO: that is current always ERR_OK?)
* @return value is currently ignored
*/
err_t (* connected)(void *arg, struct tcp_pcb *pcb, err_t err);
/* Function which is called periodically.
* The period can be adjusted in multiples of the TCP slow timer interval
* by changing tcp_pcb.polltmr.
* @param arg user-supplied argument (tcp_pcb.callback_arg)
* @param pcb the tcp_pcb to poll for
* @return ERR_OK: try to send some data by calling tcp_output
*/
err_t (* poll)(void *arg, struct tcp_pcb *pcb);
/* Function to be called whenever a fatal error occurs.
* There is no pcb parameter since most of the times, the pcb is
* already deallocated (or there is no pcb) when this function is called.
* @param arg user-supplied argument (tcp_pcb.callback_arg)
* @param err an indication why the error callback is called:
* ERR_ABRT: aborted through tcp_abort or by a TCP timer
* ERR_RST: the connection was reset by the remote host
*/
void (* errf)(void *arg, err_t err);
/* Function to be called when more send buffer space is available. */
tcp_sent_fn sent;
/* Function to be called when (in-sequence) data has arrived. */
tcp_recv_fn recv;
/* Function to be called when a connection has been set up. */
tcp_connected_fn connected;
/* Function which is called periodically. */
tcp_poll_fn poll;
/* Function to be called whenever a fatal error occurs. */
tcp_err_fn errf;
#endif /* LWIP_CALLBACK_API */
#if LWIP_TCP_TIMESTAMPS

11
src/include/lwip/tcpip.h
View File

@@ -66,7 +66,12 @@ extern sys_sem_t lock_tcpip_core;
#define TCPIP_NETIFAPI_ACK(m) sys_sem_signal(m->sem)
#endif /* LWIP_TCPIP_CORE_LOCKING */
void tcpip_init(void (* tcpip_init_done)(void *), void *arg);
/** Function prototype for the init_done function passed to tcpip_init */
typedef void (*tcpip_init_done_fn)(void *arg);
/** Function prototype for functions passed to tcpip_callback() */
typedef void (*tcpip_callback_fn)(void *ctx);
void tcpip_init(tcpip_init_done_fn tcpip_init_done, void *arg);
#if LWIP_NETCONN
err_t tcpip_apimsg(struct api_msg *apimsg);
@@ -84,7 +89,7 @@ err_t tcpip_netifapi_lock(struct netifapi_msg *netifapimsg);
#endif /* LWIP_TCPIP_CORE_LOCKING */
#endif /* LWIP_NETIF_API */
err_t tcpip_callback_with_block(void (*f)(void *ctx), void *ctx, u8_t block);
err_t tcpip_callback_with_block(tcpip_callback_fn function, void *ctx, u8_t block);
#define tcpip_callback(f, ctx) tcpip_callback_with_block(f, ctx, 1)
/* free pbufs or heap memory from another context without blocking */
@@ -122,7 +127,7 @@ struct tcpip_msg {
struct netif *netif;
} inp;
struct {
void (*f)(void *ctx);
tcpip_callback_fn function;
void *ctx;
} cb;
struct {

5
src/include/lwip/timers.h
View File

@@ -50,6 +50,11 @@ extern "C" {
#endif /* LWIP_DEBUG*/
#endif
/** Function prototype for a timeout callback function. Register such a function
* using sys_timeout().
*
* @param arg Additional argument to pass to the function - set up by sys_timeout()
*/
typedef void (* sys_timeout_handler)(void *arg);
struct sys_timeo {

69
src/include/lwip/udp.h
View File

@@ -67,6 +67,26 @@ PACK_STRUCT_END
#define UDP_FLAGS_UDPLITE 0x02U
#define UDP_FLAGS_CONNECTED 0x04U
struct udp_pcb;
/** Function prototype for udp pcb receive callback functions
* addr and port are in same byte order as in the pcb
* The callback is responsible for freeing the pbuf
* if it's not used any more.
*
* ATTENTION: Be aware that 'addr' points into the pbuf 'p' so freeing this pbuf
* makes 'addr' invalid, too.
*
* @param arg user supplied argument (udp_pcb.recv_arg)
* @param pcb the udp_pcb which received data
* @param p the packet buffer that was received
* @param addr the remote IP address from which the packet was received
* @param port the remote port from which the packet was received
*/
typedef void (*udp_recv_fn)(void *arg, struct udp_pcb *pcb, struct pbuf *p,
struct ip_addr *addr, u16_t port);
struct udp_pcb {
/* Common members of all PCB types */
IP_PCB;
@@ -76,36 +96,22 @@ struct udp_pcb {
struct udp_pcb *next;
u8_t flags;
/* ports are in host byte order */
/** ports are in host byte order */
u16_t local_port, remote_port;
#if LWIP_IGMP
/* outgoing network interface for multicast packets */
/** outgoing network interface for multicast packets */
struct ip_addr multicast_ip;
#endif /* LWIP_IGMP */
#if LWIP_UDPLITE
/* used for UDP_LITE only */
/** used for UDP_LITE only */
u16_t chksum_len_rx, chksum_len_tx;
#endif /* LWIP_UDPLITE */
/* receive callback function
* addr and port are in same byte order as in the pcb
* The callback is responsible for freeing the pbuf
* if it's not used any more.
*
* ATTENTION: Be aware that 'addr' points into the pbuf 'p' so freeing this pbuf
* makes 'addr' invalid, too.
*
* @param arg user supplied argument (udp_pcb.recv_arg)
* @param pcb the udp_pcb which received data
* @param p the packet buffer that was received
* @param addr the remote IP address from which the packet was received
* @param port the remote port from which the packet was received
*/
void (* recv)(void *arg, struct udp_pcb *pcb, struct pbuf *p,
struct ip_addr *addr, u16_t port);
/* user-supplied argument for the recv callback */
/** receive callback function */
udp_recv_fn recv;
/** user-supplied argument for the recv callback */
void *recv_arg;
};
/* udp_pcbs export for exernal reference (e.g. SNMP agent) */
@@ -116,21 +122,20 @@ extern struct udp_pcb *udp_pcbs;
struct udp_pcb * udp_new (void);
void udp_remove (struct udp_pcb *pcb);
err_t udp_bind (struct udp_pcb *pcb, struct ip_addr *ipaddr,
u16_t port);
u16_t port);
err_t udp_connect (struct udp_pcb *pcb, struct ip_addr *ipaddr,
u16_t port);
void udp_disconnect (struct udp_pcb *pcb);
void udp_recv (struct udp_pcb *pcb,
void (* recv)(void *arg, struct udp_pcb *upcb,
struct pbuf *p,
struct ip_addr *addr,
u16_t port),
void *recv_arg);
err_t udp_sendto_if (struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *dst_ip, u16_t dst_port, struct netif *netif);
err_t udp_sendto (struct udp_pcb *pcb, struct pbuf *p, struct ip_addr *dst_ip, u16_t dst_port);
u16_t port);
void udp_disconnect (struct udp_pcb *pcb);
void udp_recv (struct udp_pcb *pcb, udp_recv_fn recv,
void *recv_arg);
err_t udp_sendto_if (struct udp_pcb *pcb, struct pbuf *p,
struct ip_addr *dst_ip, u16_t dst_port,
struct netif *netif);
err_t udp_sendto (struct udp_pcb *pcb, struct pbuf *p,
struct ip_addr *dst_ip, u16_t dst_port);
err_t udp_send (struct udp_pcb *pcb, struct pbuf *p);
#define udp_flags(pcb) ((pcb)->flags)
#define udp_flags(pcb) ((pcb)->flags)
#define udp_setflags(pcb, f) ((pcb)->flags = (f))
/* The following functions are the lower layer interface to UDP. */