udp.h

LwIP是瑞士计算机科学院(Swedish Institute of Computer Science)的AdamDunkels等开发的一套用于嵌入式系统的开放源代码TCP/IP协议栈。LwIP的含义

/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved. 
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT 
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT 
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING 
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 * 
 * Author: Adam Dunkels <[e-mail]>
 *
 */
#ifndef __LWIP_UDP_H__
#define __LWIP_UDP_H__

#include "lwip/arch.h"

#include "lwip/pbuf.h"
#include "lwip/inet.h"
#include "lwip/ip.h"

#define UDP_HLEN 8

struct udp_hdr {
  PACK_STRUCT_FIELD(u16_t src);
  PACK_STRUCT_FIELD(u16_t dest);  /* src/dest UDP ports */
  PACK_STRUCT_FIELD(u16_t len);
  PACK_STRUCT_FIELD(u16_t chksum);
} PACK_STRUCT_STRUCT;

#define UDP_FLAGS_NOCHKSUM 0x01U
#define UDP_FLAGS_UDPLITE  0x02U
#define UDP_FLAGS_CONNECTED  0x04U

struct udp_pcb {
/* Common members of all PCB types */
  IP_PCB;

/* Protocol specific PCB members */

  struct udp_pcb *next;

  u8_t flags;
  u16_t local_port, remote_port;
  
  u16_t chksum_len;
  
  void (* recv)(void *arg, struct udp_pcb *pcb, struct pbuf *p,
    struct ip_addr *addr, u16_t port);
  void *recv_arg;  
};
/* udp_pcbs export for exernal reference (e.g. SNMP agent) */
extern struct udp_pcb *udp_pcbs;

/* The following functions is the application layer interface to the
   UDP code. */
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);
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     (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_setflags(pcb, f)  ((pcb)->flags = (f))

/* The following functions are the lower layer interface to UDP. */
void             udp_input      (struct pbuf *p, struct netif *inp);
void             udp_init       (void);

#if UDP_DEBUG
void udp_debug_print(struct udp_hdr *udphdr);
#else
#define udp_debug_print(udphdr)
#endif
#endif /* __LWIP_UDP_H__ */