text: /****************************************************************************
   *
   * Copyright 2016 Samsung Electronics All Rights Reserved.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied. See the License for the specific
   * language governing permissions and limitations under the License.
   *
   ****************************************************************************/
  /*
   * 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 <adam@sics.se>
   *
   */
  #ifndef LWIP_HDR_API_H
  #define LWIP_HDR_API_H
  
  #include "lwip/opt.h"
  
  #if LWIP_NETCONN || LWIP_SOCKET	/* don't build if not configured for use in lwipopts.h */
  /*
   * Note: Netconn API is always available when sockets are enabled -
   * sockets are implemented on top of them
   */
  
  #include "lwip/arch.h"
  #include "lwip/netbuf.h"
  #include "lwip/sys.h"
  #include "lwip/ip_addr.h"
  #include "lwip/err.h"
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /* Throughout this file, IP addresses and port numbers are expected to be in
   * the same byte order as in the corresponding pcb.
   */
  
  /* Flags for netconn_write (u8_t) */
  #define NETCONN_NOFLAG    0x00
  #define NETCONN_NOCOPY    0x00	/* Only for source code compatibility */
  #define NETCONN_COPY      0x01
  #define NETCONN_MORE      0x02
  #define NETCONN_DONTBLOCK 0x04
  
  /* Flags for struct netconn.flags (u8_t) */
  /*
   * TCP: when data passed to netconn_write doesn't fit into the send buffer,
   * this temporarily stores whether to wake up the original application task
   * if data couldn't be sent in the first try.
   */
  #define NETCONN_FLAG_WRITE_DELAYED            0x01
  /* Should this netconn avoid blocking? */
  #define NETCONN_FLAG_NON_BLOCKING             0x02
  /* Was the last connect action a non-blocking one? */
  #define NETCONN_FLAG_IN_NONBLOCKING_CONNECT   0x04
  /*
   * If this is set, a TCP netconn must call netconn_recved() to update
   * the TCP receive window (done automatically if not set).
   */
  #define NETCONN_FLAG_NO_AUTO_RECVED           0x08
  /*
   * If a nonblocking write has been rejected before, poll_tcp needs to
   * check if the netconn is writable again
   */
  #define NETCONN_FLAG_CHECK_WRITESPACE         0x10
  #if LWIP_IPV6
  /*
   * If this flag is set then only IPv6 communication is allowed on the
   * netconn. As per RFC#3493 this features defaults to OFF allowing
   * dual-stack usage by default.
   */
  #define NETCONN_FLAG_IPV6_V6ONLY              0x20
  #endif							/* LWIP_IPV6 */
  
  /* Helpers to process several netconn_types by the same code */
  #define NETCONNTYPE_GROUP(t)         ((t) & 0xF0)
  #define NETCONNTYPE_DATAGRAM(t)      ((t) & 0xE0)
  #if LWIP_IPV6
  #define NETCONN_TYPE_IPV6            0x08
  #define NETCONNTYPE_ISIPV6(t)        (((t) & NETCONN_TYPE_IPV6) != 0)
  #define NETCONNTYPE_ISUDPLITE(t)     (((t) & 0xF3) == NETCONN_UDPLITE)
  #define NETCONNTYPE_ISUDPNOCHKSUM(t) (((t) & 0xF3) == NETCONN_UDPNOCHKSUM)
  #else							/* LWIP_IPV6 */
  #define NETCONNTYPE_ISIPV6(t)        (0)
  #define NETCONNTYPE_ISUDPLITE(t)     ((t) == NETCONN_UDPLITE)
  #define NETCONNTYPE_ISUDPNOCHKSUM(t) ((t) == NETCONN_UDPNOCHKSUM)
  #endif							/* LWIP_IPV6 */
  
  enum netconn_type {
  	NETCONN_INVALID = 0,
  	/* TCP IPv4 */
  	NETCONN_TCP = 0x10,
  #if LWIP_IPV6
  	/* TCP IPv6 */
  	NETCONN_TCP_IPV6 = NETCONN_TCP | NETCONN_TYPE_IPV6,	/* 0x18 */
  #endif							/* LWIP_IPV6 */
  	/* UDP IPv4 */
  	NETCONN_UDP = 0x20,
  	/* UDP IPv4 lite */
  	NETCONN_UDPLITE = 0x21,
  	/* UDP IPv4 no checksum */
  	NETCONN_UDPNOCHKSUM = 0x22,
  
  #if LWIP_IPV6
  	/* UDP IPv6 (dual-stack by default, unless you call @ref netconn_set_ipv6only) */
  	NETCONN_UDP_IPV6 = NETCONN_UDP | NETCONN_TYPE_IPV6,	/* 0x28 */
  	/* UDP IPv6 lite (dual-stack by default, unless you call @ref netconn_set_ipv6only) */
  	NETCONN_UDPLITE_IPV6 = NETCONN_UDPLITE | NETCONN_TYPE_IPV6,	/* 0x29 */
  	/* UDP IPv6 no checksum (dual-stack by default, unless you call @ref netconn_set_ipv6only) */
  	NETCONN_UDPNOCHKSUM_IPV6 = NETCONN_UDPNOCHKSUM | NETCONN_TYPE_IPV6,	/* 0x2a */
  #endif							/* LWIP_IPV6 */
  
  	/* Raw connection IPv4 */
  	NETCONN_RAW = 0x40,
  #if LWIP_IPV6
  	/* Raw connection IPv6 (dual-stack by default, unless you call @ref netconn_set_ipv6only) */
  	NETCONN_RAW_IPV6 = NETCONN_RAW | NETCONN_TYPE_IPV6	/* 0x48 */
  #endif							/* LWIP_IPV6 */
  };
  
  /*
   * Current state of the netconn. Non-TCP netconns are always
   * in state NETCONN_NONE!
   */
  enum netconn_state {
  	NETCONN_NONE,
  	NETCONN_WRITE,
  	NETCONN_LISTEN,
  	NETCONN_CONNECT,
  	NETCONN_CLOSE
  };
  
  /*
   * Used to inform the callback function about changes
   *
   * Event explanation:
   *
   * In the netconn implementation, there are three ways to block a client:
   *
   * - accept mbox (sys_arch_mbox_fetch(&conn->acceptmbox, &accept_ptr, 0); in netconn_accept())
   * - receive mbox (sys_arch_mbox_fetch(&conn->recvmbox, &buf, 0); in netconn_recv_data())
   * - send queue is full (sys_arch_sem_wait(LWIP_API_MSG_SEM(msg), 0); in lwip_netconn_do_write())
   *
   * The events have to be seen as events signaling the state of these mboxes/semaphores. For non-blocking
   * connections, you need to know in advance whether a call to a netconn function call would block or not,
   * and these events tell you about that.
   *
   * RCVPLUS events say: Safe to perform a potentially blocking call call once more.
   * They are counted in sockets - three RCVPLUS events for accept mbox means you are safe
   * to call netconn_accept 3 times without being blocked.
   * Same thing for receive mbox.
   *
   * RCVMINUS events say: Your call to to a possibly blocking function is "acknowledged".
   * Socket implementation decrements the counter.
   *
   * For TX, there is no need to count, its merely a flag. SENDPLUS means you may send something.
   * SENDPLUS occurs when enough data was delivered to peer so netconn_send() can be called again.
   * A SENDMINUS event occurs when the next call to a netconn_send() would be blocking.
   */
  enum netconn_evt {
  	NETCONN_EVT_RCVPLUS,
  	NETCONN_EVT_RCVMINUS,
  	NETCONN_EVT_SENDPLUS,
  	NETCONN_EVT_SENDMINUS,
  	NETCONN_EVT_ERROR
  };
  
  #if LWIP_IGMP || (LWIP_IPV6 && LWIP_IPV6_MLD)
  /* Used for netconn_join_leave_group() */
  enum netconn_igmp {
  	NETCONN_JOIN,
  	NETCONN_LEAVE
  };
  #endif							/* LWIP_IGMP || (LWIP_IPV6 && LWIP_IPV6_MLD) */
  
  #if LWIP_DNS
  /* Used for netconn_gethostbyname_addrtype(), these should match the DNS_ADDRTYPE defines in dns.h */
  #define NETCONN_DNS_DEFAULT   NETCONN_DNS_IPV4_IPV6
  #define NETCONN_DNS_IPV4      0
  #define NETCONN_DNS_IPV6      1
  #define NETCONN_DNS_IPV4_IPV6 2	/* try to resolve IPv4 first, try IPv6 if IPv4 fails only */
  #define NETCONN_DNS_IPV6_IPV4 3	/* try to resolve IPv6 first, try IPv4 if IPv6 fails only */
  #endif							/* LWIP_DNS */
  
  /* forward-declare some structs to avoid to include their headers */
  struct ip_pcb;
  struct tcp_pcb;
  struct udp_pcb;
  struct raw_pcb;
  struct netconn;
  struct api_msg;
  
  /* A callback prototype to inform about events for a netconn */
  typedef void (*netconn_callback)(struct netconn *, enum netconn_evt, u16_t len);
  
  /* A netconn descriptor */
  struct netconn {
  	/* type of the netconn (TCP, UDP or RAW) */
  	enum netconn_type type;
  	/* current state of the netconn */
  	enum netconn_state state;
  	/* the lwIP internal protocol control block */
  	union {
  		struct ip_pcb *ip;
  		struct tcp_pcb *tcp;
  		struct udp_pcb *udp;
  		struct raw_pcb *raw;
  	} pcb;
  	/* the last error this netconn had */
  	err_t last_err;
  #if !LWIP_NETCONN_SEM_PER_THREAD
  	/* sem that is used to synchronously execute functions in the core context */
  	sys_sem_t op_completed;
  	/* sem that is used to synchroneously post messages on the netconn in tcpip_apimsg() */
  	sys_sem_t op_sync;
  #endif
  
  	/*
  	 * mbox where received packets are stored until they are fetched
  	 * by the netconn application thread (can grow quite big)
  	 */
  	sys_mbox_t recvmbox;
  #if LWIP_TCP
  	/*
  	 *  mbox where new connections are stored until processed
  	 *  by the application thread
  	 */
  	sys_mbox_t acceptmbox;
  #endif							/* LWIP_TCP */
  	/* only used for socket layer */
  #if LWIP_SOCKET
  	int socket;
  	struct socketlist *slist;
  	/* interoperability with tinyara network stack */
  	int crefs;				/* for dup */
  #endif							/* LWIP_SOCKET */
  #if LWIP_SO_SNDTIMEO
  	/* timeout to wait for sending data (which means enqueueing data for sending
  	   in internal buffers) in milliseconds */
  	s32_t send_timeout;
  #endif							/* LWIP_SO_RCVTIMEO */
  #if LWIP_SO_RCVTIMEO
  	/* timeout in milliseconds to wait for new data to be received
  	   (or connections to arrive for listening netconns) */
  	int recv_timeout;
  #endif							/* LWIP_SO_RCVTIMEO */
  #if LWIP_SO_RCVBUF
  	/* maximum amount of bytes queued in recvmbox
  	   not used for TCP: adjust TCP_WND instead! */
  	int recv_bufsize;
  	/* number of bytes currently in recvmbox to be received,
  	   tested against recv_bufsize to limit bytes on recvmbox
  	   for UDP and RAW, used for FIONREAD */
  	int recv_avail;
  #endif							/* LWIP_SO_RCVBUF */
  #if LWIP_SO_LINGER
  	/* values <0 mean linger is disabled, values > 0 are seconds to linger */
  	s16_t linger;
  #endif							/* LWIP_SO_LINGER */
  	/* flags holding more netconn-internal state, see NETCONN_FLAG_* defines */
  	u8_t flags;
  #if LWIP_TCP
  	/* TCP: when data passed to netconn_write doesn't fit into the send buffer,
  	   this temporarily stores how much is already sent. */
  	size_t write_offset;
  	/* TCP: when data passed to netconn_write doesn't fit into the send buffer,
  	   this temporarily stores the message.
  	   Also used during connect and close. */
  	struct api_msg *current_msg;
  #endif							/* LWIP_TCP */
  	/* A callback function that is informed about events for this netconn */
  	netconn_callback callback;
  	/* pid information that generates netconn */
  	pid_t pid;
  };
  
  /* Register an Network connection event */
  #define API_EVENT(c, e, l) if (c->callback) { \
  							 (*(c->callback))(c, e, l); \
  						   }
  
  /* Set conn->last_err to err but don't overwrite fatal errors */
  #define NETCONN_SET_SAFE_ERR(conn, err) do { if ((conn) != NULL) { \
  	SYS_ARCH_DECL_PROTECT(netconn_set_safe_err_lev); \
  	SYS_ARCH_PROTECT(netconn_set_safe_err_lev); \
  	if (!ERR_IS_FATAL((conn)->last_err)) { \
  		(conn)->last_err = err; \
  	} \
  	SYS_ARCH_UNPROTECT(netconn_set_safe_err_lev); \
  } } while (0)
  
  /* Network connection functions: */
  
  #define netconn_new(t)                  netconn_new_with_proto_and_callback(t, 0, NULL)
  #define netconn_new_with_callback(t, c) netconn_new_with_proto_and_callback(t, 0, c)
  struct netconn *netconn_new_with_proto_and_callback(enum netconn_type t, u8_t proto, netconn_callback callback);
  err_t netconn_delete(struct netconn *conn);
  /* Get the type of a netconn (as enum netconn_type). */
  #define netconn_type(conn) (conn->type)
  
  err_t netconn_getaddr(struct netconn *conn, ip_addr_t *addr, u16_t *port, u8_t local);
  #define netconn_peer(c, i, p) netconn_getaddr(c, i, p, 0)
  #define netconn_addr(c, i, p) netconn_getaddr(c, i, p, 1)
  
  err_t netconn_bind(struct netconn *conn, const ip_addr_t *addr, u16_t port);
  err_t netconn_connect(struct netconn *conn, const ip_addr_t *addr, u16_t port);
  err_t netconn_disconnect(struct netconn *conn);
  err_t netconn_listen_with_backlog(struct netconn *conn, u8_t backlog);
  #define netconn_listen(conn) netconn_listen_with_backlog(conn, TCP_DEFAULT_LISTEN_BACKLOG)
  err_t netconn_accept(struct netconn *conn, struct netconn **new_conn);
  err_t netconn_recv(struct netconn *conn, struct netbuf **new_buf);
  err_t netconn_recv_tcp_pbuf(struct netconn *conn, struct pbuf **new_buf);
  err_t netconn_sendto(struct netconn *conn, struct netbuf *buf, const ip_addr_t *addr, u16_t port);
  err_t netconn_send(struct netconn *conn, struct netbuf *buf);
  err_t netconn_write_partly(struct netconn *conn, const void *dataptr, size_t size, u8_t apiflags, size_t *bytes_written);
  #define netconn_write(conn, dataptr, size, apiflags) \
  		netconn_write_partly(conn, dataptr, size, apiflags, NULL)
  err_t netconn_close(struct netconn *conn);
  err_t netconn_shutdown(struct netconn *conn, u8_t shut_rx, u8_t shut_tx);
  
  #if LWIP_IGMP || (LWIP_IPV6 && LWIP_IPV6_MLD)
  err_t netconn_join_leave_group(struct netconn *conn, const ip_addr_t *multiaddr, const ip_addr_t *netif_addr, enum netconn_igmp join_or_leave);
  #endif							/* LWIP_IGMP || (LWIP_IPV6 && LWIP_IPV6_MLD) */
  #if LWIP_DNS
  #if LWIP_IPV4 && LWIP_IPV6
  err_t netconn_gethostbyname_addrtype(const char *name, ip_addr_t *addr, u8_t dns_addrtype);
  #define netconn_gethostbyname(name, addr) netconn_gethostbyname_addrtype(name, addr, NETCONN_DNS_DEFAULT)
  #else							/* LWIP_IPV4 && LWIP_IPV6 */
  err_t netconn_gethostbyname(const char *name, ip_addr_t *addr);
  #define netconn_gethostbyname_addrtype(name, addr, dns_addrtype) netconn_gethostbyname(name, addr)
  #endif							/* LWIP_IPV4 && LWIP_IPV6 */
  #endif							/* LWIP_DNS */
  
  #define netconn_err(conn)               ((conn)->last_err)
  #define netconn_recv_bufsize(conn)      ((conn)->recv_bufsize)
  
  /* Set the blocking status of netconn calls (@todo: write/send is missing) */
  #define netconn_set_nonblocking(conn, val)  do { if (val) { \
  	(conn)->flags |= NETCONN_FLAG_NON_BLOCKING; \
  } else { \
  	(conn)->flags &= ~NETCONN_FLAG_NON_BLOCKING; } \
  } while (0)
  /* Get the blocking status of netconn calls (@todo: write/send is missing) */
  #define netconn_is_nonblocking(conn)        (((conn)->flags & NETCONN_FLAG_NON_BLOCKING) != 0)
  
  #if LWIP_IPV6
  #define netconn_set_ipv6only(conn, val)  do { if (val) { \
  	(conn)->flags |= NETCONN_FLAG_IPV6_V6ONLY; \
  } else { \
  	(conn)->flags &= ~NETCONN_FLAG_IPV6_V6ONLY; } \
  } while (0)
  #define netconn_get_ipv6only(conn)        (((conn)->flags & NETCONN_FLAG_IPV6_V6ONLY) != 0)
  #endif							/* LWIP_IPV6 */
  
  #if LWIP_SO_SNDTIMEO
  /* Set the send timeout in milliseconds */
  #define netconn_set_sendtimeout(conn, timeout)      ((conn)->send_timeout = (timeout))
  /* Get the send timeout in milliseconds */
  #define netconn_get_sendtimeout(conn)               ((conn)->send_timeout)
  #endif							/* LWIP_SO_SNDTIMEO */
  #if LWIP_SO_RCVTIMEO
  /* Set the receive timeout in milliseconds */
  #define netconn_set_recvtimeout(conn, timeout)      ((conn)->recv_timeout = (timeout))
  /* Get the receive timeout in milliseconds */
  #define netconn_get_recvtimeout(conn)               ((conn)->recv_timeout)
  #endif							/* LWIP_SO_RCVTIMEO */
  #if LWIP_SO_RCVBUF
  /* Set the receive buffer in bytes */
  #define netconn_set_recvbufsize(conn, recvbufsize)  ((conn)->recv_bufsize = (recvbufsize))
  /* Get the receive buffer in bytes */
  #define netconn_get_recvbufsize(conn)               ((conn)->recv_bufsize)
  #endif							/* LWIP_SO_RCVBUF */
  
  #if LWIP_NETCONN_SEM_PER_THREAD
  void netconn_thread_init(void);
  void netconn_thread_cleanup(void);
  #else							/* LWIP_NETCONN_SEM_PER_THREAD */
  #define netconn_thread_init()
  #define netconn_thread_cleanup()
  #endif							/* LWIP_NETCONN_SEM_PER_THREAD */
  
  #ifdef __cplusplus
  }
  #endif
  #endif							/* LWIP_NETCONN || LWIP_SOCKET */
  #endif							/* LWIP_HDR_API_H */
  