Diff: include/lwip/tcp.h

Revision:

0:51ac1d130fd4

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/lwip/tcp.h	Fri Jun 22 09:25:39 2012 +0000
@@ -0,0 +1,377 @@
+/*
+ * 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_TCP_H__
+#define __LWIP_TCP_H__
+
+#include "lwip/opt.h"
+
+#if LWIP_TCP /* don't build if not configured for use in lwipopts.h */
+
+#include "lwip/sys.h"
+#include "lwip/mem.h"
+#include "lwip/pbuf.h"
+#include "lwip/ip.h"
+#include "lwip/icmp.h"
+#include "lwip/err.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+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.
+ *            Only return ERR_ABRT if you have called tcp_abort from within the
+ *            callback function!
+ */
+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
+ *            Only return ERR_ABRT if you have called tcp_abort from within the
+ *            callback function!
+ */
+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
+ *            Only return ERR_ABRT if you have called tcp_abort from within the
+ *            callback function!
+ */
+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
+ *            Only return ERR_ABRT if you have called tcp_abort from within the
+ *            callback function!
+ */
+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!
+ *            Only return ERR_ABRT if you have called tcp_abort from within the
+ *            callback function!
+ *
+ * @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);
+
+enum tcp_state {
+  CLOSED      = 0,
+  LISTEN      = 1,
+  SYN_SENT    = 2,
+  SYN_RCVD    = 3,
+  ESTABLISHED = 4,
+  FIN_WAIT_1  = 5,
+  FIN_WAIT_2  = 6,
+  CLOSE_WAIT  = 7,
+  CLOSING     = 8,
+  LAST_ACK    = 9,
+  TIME_WAIT   = 10
+};
+
+#if LWIP_CALLBACK_API
+  /* Function to call when a listener has been connected.
+   * @param arg user-supplied argument (tcp_pcb.callback_arg)
+   * @param pcb a new tcp_pcb that now is connected
+   * @param err an error argument (TODO: that is current always ERR_OK?)
+   * @return ERR_OK: accept the new connection,
+   *                 any other err_t abortsthe new connection
+   */
+#define DEF_ACCEPT_CALLBACK  tcp_accept_fn accept;
+#else /* LWIP_CALLBACK_API */
+#define DEF_ACCEPT_CALLBACK
+#endif /* LWIP_CALLBACK_API */
+
+/**
+ * members common to struct tcp_pcb and struct tcp_listen_pcb
+ */
+#define TCP_PCB_COMMON(type) \
+  type *next; /* for the linked list */ \
+  enum tcp_state state; /* TCP state */ \
+  u8_t prio; \
+  void *callback_arg; \
+  /* the accept callback for listen- and normal pcbs, if LWIP_CALLBACK_API */ \
+  DEF_ACCEPT_CALLBACK \
+  /* ports are in host byte order */ \
+  u16_t local_port
+
+
+/* the TCP protocol control block */
+struct tcp_pcb {
+/** common PCB members */
+  IP_PCB;
+/** protocol specific PCB members */
+  TCP_PCB_COMMON(struct tcp_pcb);
+
+  /* ports are in host byte order */
+  u16_t remote_port;
+  
+  u8_t flags;
+#define TF_ACK_DELAY   ((u8_t)0x01U)   /* Delayed ACK. */
+#define TF_ACK_NOW     ((u8_t)0x02U)   /* Immediate ACK. */
+#define TF_INFR        ((u8_t)0x04U)   /* In fast recovery. */
+#define TF_TIMESTAMP   ((u8_t)0x08U)   /* Timestamp option enabled */
+#define TF_RXCLOSED    ((u8_t)0x10U)   /* rx closed by tcp_shutdown */
+#define TF_FIN         ((u8_t)0x20U)   /* Connection was closed locally (FIN segment enqueued). */
+#define TF_NODELAY     ((u8_t)0x40U)   /* Disable Nagle algorithm */
+#define TF_NAGLEMEMERR ((u8_t)0x80U)   /* nagle enabled, memerr, try to output to prevent delayed ACK to happen */
+
+  /* the rest of the fields are in host byte order
+     as we have to do some math with them */
+  /* receiver variables */
+  u32_t rcv_nxt;   /* next seqno expected */
+  u16_t rcv_wnd;   /* receiver window available */
+  u16_t rcv_ann_wnd; /* receiver window to announce */
+  u32_t rcv_ann_right_edge; /* announced right edge of window */
+
+  /* Timers */
+  u32_t tmr;
+  u8_t polltmr, pollinterval;
+  
+  /* Retransmission timer. */
+  s16_t rtime;
+  
+  u16_t mss;   /* maximum segment size */
+  
+  /* RTT (round trip time) estimation variables */
+  u32_t rttest; /* RTT estimate in 500ms ticks */
+  u32_t rtseq;  /* sequence number being timed */
+  s16_t sa, sv; /* @todo document this */
+
+  s16_t rto;    /* retransmission time-out */
+  u8_t nrtx;    /* number of retransmissions */
+
+  /* fast retransmit/recovery */
+  u32_t lastack; /* Highest acknowledged seqno. */
+  u8_t dupacks;
+  
+  /* congestion avoidance/control variables */
+  u16_t cwnd;  
+  u16_t ssthresh;
+
+  /* sender variables */
+  u32_t snd_nxt;   /* next new seqno to be sent */
+  u16_t snd_wnd;   /* sender window */
+  u32_t snd_wl1, snd_wl2; /* Sequence and acknowledgement numbers of last
+                             window update. */
+  u32_t snd_lbb;       /* Sequence number of next byte to be buffered. */
+
+  u16_t acked;
+  
+  u16_t snd_buf;   /* Available buffer space for sending (in bytes). */
+#define TCP_SNDQUEUELEN_OVERFLOW (0xffffU-3)
+  u16_t snd_queuelen; /* Available buffer space for sending (in tcp_segs). */
+
+#if TCP_OVERSIZE
+  /* Extra bytes available at the end of the last pbuf in unsent. */
+  u16_t unsent_oversize;
+#endif /* TCP_OVERSIZE */ 
+
+  /* These are ordered by sequence number: */
+  struct tcp_seg *unsent;   /* Unsent (queued) segments. */
+  struct tcp_seg *unacked;  /* Sent but unacknowledged segments. */
+#if TCP_QUEUE_OOSEQ  
+  struct tcp_seg *ooseq;    /* Received out of sequence segments. */
+#endif /* TCP_QUEUE_OOSEQ */
+
+  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. */
+  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
+  u32_t ts_lastacksent;
+  u32_t ts_recent;
+#endif /* LWIP_TCP_TIMESTAMPS */
+
+  /* idle time before KEEPALIVE is sent */
+  u32_t keep_idle;
+#if LWIP_TCP_KEEPALIVE
+  u32_t keep_intvl;
+  u32_t keep_cnt;
+#endif /* LWIP_TCP_KEEPALIVE */
+  
+  /* Persist timer counter */
+  u32_t persist_cnt;
+  /* Persist timer back-off */
+  u8_t persist_backoff;
+
+  /* KEEPALIVE counter */
+  u8_t keep_cnt_sent;
+};
+
+struct tcp_pcb_listen {  
+/* Common members of all PCB types */
+  IP_PCB;
+/* Protocol specific PCB members */
+  TCP_PCB_COMMON(struct tcp_pcb_listen);
+
+#if TCP_LISTEN_BACKLOG
+  u8_t backlog;
+  u8_t accepts_pending;
+#endif /* TCP_LISTEN_BACKLOG */
+};
+
+#if LWIP_EVENT_API
+
+enum lwip_event {
+  LWIP_EVENT_ACCEPT,
+  LWIP_EVENT_SENT,
+  LWIP_EVENT_RECV,
+  LWIP_EVENT_CONNECTED,
+  LWIP_EVENT_POLL,
+  LWIP_EVENT_ERR
+};
+
+err_t lwip_tcp_event(void *arg, struct tcp_pcb *pcb,
+         enum lwip_event,
+         struct pbuf *p,
+         u16_t size,
+         err_t err);
+
+#endif /* LWIP_EVENT_API */
+
+/* Application program's interface: */
+struct tcp_pcb * tcp_new     (void);
+
+void             tcp_arg     (struct tcp_pcb *pcb, void *arg);
+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)->flags & TF_TIMESTAMP) ? ((pcb)->mss - 12)  : (pcb)->mss)
+#define          tcp_sndbuf(pcb)          ((pcb)->snd_buf)
+#define          tcp_sndqueuelen(pcb)     ((pcb)->snd_queuelen)
+#define          tcp_nagle_disable(pcb)   ((pcb)->flags |= TF_NODELAY)
+#define          tcp_nagle_enable(pcb)    ((pcb)->flags &= ~TF_NODELAY)
+#define          tcp_nagle_disabled(pcb)  (((pcb)->flags & TF_NODELAY) != 0)
+
+#if TCP_LISTEN_BACKLOG
+#define          tcp_accepted(pcb) do { \
+  LWIP_ASSERT("pcb->state == LISTEN (called for wrong pcb?)", pcb->state == LISTEN); \
+  (((struct tcp_pcb_listen *)(pcb))->accepts_pending--); } while(0)
+#else  /* TCP_LISTEN_BACKLOG */
+#define          tcp_accepted(pcb) LWIP_ASSERT("pcb->state == LISTEN (called for wrong pcb?)", \
+                                               pcb->state == LISTEN)
+#endif /* TCP_LISTEN_BACKLOG */
+
+void             tcp_recved  (struct tcp_pcb *pcb, u16_t len);
+err_t            tcp_bind    (struct tcp_pcb *pcb, ip_addr_t *ipaddr,
+                              u16_t port);
+err_t            tcp_connect (struct tcp_pcb *pcb, ip_addr_t *ipaddr,
+                              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)
+
+void             tcp_abort (struct tcp_pcb *pcb);
+err_t            tcp_close   (struct tcp_pcb *pcb);
+err_t            tcp_shutdown(struct tcp_pcb *pcb, int shut_rx, int shut_tx);
+
+/* Flags for "apiflags" parameter in tcp_write */
+#define TCP_WRITE_FLAG_COPY 0x01
+#define TCP_WRITE_FLAG_MORE 0x02
+
+err_t            tcp_write   (struct tcp_pcb *pcb, const void *dataptr, u16_t len,
+                              u8_t apiflags);
+
+void             tcp_setprio (struct tcp_pcb *pcb, u8_t prio);
+
+#define TCP_PRIO_MIN    1
+#define TCP_PRIO_NORMAL 64
+#define TCP_PRIO_MAX    127
+
+err_t            tcp_output  (struct tcp_pcb *pcb);
+
+
+const char* tcp_debug_state_str(enum tcp_state s);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* LWIP_TCP */
+
+#endif /* __LWIP_TCP_H__ */