tcp.h

LWIP在STM32裸机上的移植

  u16_t snd_queuelen; /* Available buffer space for sending (in tcp_segs). */
  
  
  /* 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.
   * @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);
#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);

#define TCP_EVENT_ACCEPT(pcb,err,ret)    ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
                LWIP_EVENT_ACCEPT, NULL, 0, err)
#define TCP_EVENT_SENT(pcb,space,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
                   LWIP_EVENT_SENT, NULL, space, ERR_OK)
#define TCP_EVENT_RECV(pcb,p,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
                LWIP_EVENT_RECV, (p), 0, (err))
#define TCP_EVENT_CONNECTED(pcb,err,ret) ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
                LWIP_EVENT_CONNECTED, NULL, 0, (err))
#define TCP_EVENT_POLL(pcb,ret)       ret = lwip_tcp_event((pcb)->callback_arg, (pcb),\
                LWIP_EVENT_POLL, NULL, 0, ERR_OK)
#define TCP_EVENT_ERR(errf,arg,err)  lwip_tcp_event((arg), NULL, \
                LWIP_EVENT_ERR, NULL, 0, (err))
#else /* LWIP_EVENT_API */

#define TCP_EVENT_ACCEPT(pcb,err,ret)                          \
  do {                                                         \
    if((pcb)->accept != NULL)                                  \
      (ret) = (pcb)->accept((pcb)->callback_arg,(pcb),(err));  \
    else (ret) = ERR_OK;                                       \
  } while (0)

#define TCP_EVENT_SENT(pcb,space,ret)                          \
  do {                                                         \
    if((pcb)->sent != NULL)                                    \
      (ret) = (pcb)->sent((pcb)->callback_arg,(pcb),(space));  \
    else (ret) = ERR_OK;                                       \
  } while (0)

#define TCP_EVENT_RECV(pcb,p,err,ret)                           \
  do {                                                          \
    if((pcb)->recv != NULL) {                                   \
      (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),(p),(err)); \
    } else {                                                    \
      (ret) = ERR_OK;                                           \
      if (p != NULL)                                            \
        pbuf_free(p);                                           \
    }                                                           \
  } while (0)

#define TCP_EVENT_CONNECTED(pcb,err,ret)                         \
  do {                                                           \
    if((pcb)->connected != NULL)                                 \
      (ret) = (pcb)->connected((pcb)->callback_arg,(pcb),(err)); \
    else (ret) = ERR_OK;                                         \
  } while (0)

#define TCP_EVENT_POLL(pcb,ret)                                \
  do {                                                         \
    if((pcb)->poll != NULL)                                    \
      (ret) = (pcb)->poll((pcb)->callback_arg,(pcb));          \
    else (ret) = ERR_OK;                                       \
  } while (0)

#define TCP_EVENT_ERR(errf,arg,err)                            \
  do {                                                         \
    if((errf) != NULL)                                         \
      (errf)((arg),(err));                                     \
  } while (0)

#endif /* LWIP_EVENT_API */

/* This structure represents a TCP segment on the unsent and unacked queues */
struct tcp_seg {
  struct tcp_seg *next;    /* used when putting segements on a queue */
  struct pbuf *p;          /* buffer containing data + TCP header */
  void *dataptr;           /* pointer to the TCP data in the pbuf */
  u16_t len;               /* the TCP length of this segment */
  u8_t  flags;
#define TF_SEG_OPTS_MSS   (u8_t)0x01U   /* Include MSS option. */
#define TF_SEG_OPTS_TS    (u8_t)0x02U   /* Include timestamp option. */
  struct tcp_hdr *tcphdr;  /* the TCP header */
};

#define LWIP_TCP_OPT_LENGTH(flags)              \
  (flags & TF_SEG_OPTS_MSS ? 4  : 0) +          \
  (flags & TF_SEG_OPTS_TS  ? 12 : 0)

/** This returns a TCP header option for MSS in an u32_t */
#define TCP_BUILD_MSS_OPTION(x) (x) = htonl(((u32_t)2 << 24) |          \
                                            ((u32_t)4 << 16) |          \
                                            (((u32_t)TCP_MSS / 256) << 8) | \
                                            (TCP_MSS & 255))

/* Internal functions and global variables: */
struct tcp_pcb *tcp_pcb_copy(struct tcp_pcb *pcb);
void tcp_pcb_purge(struct tcp_pcb *pcb);
void tcp_pcb_remove(struct tcp_pcb **pcblist, struct tcp_pcb *pcb);

u8_t tcp_segs_free(struct tcp_seg *seg);
u8_t tcp_seg_free(struct tcp_seg *seg);
struct tcp_seg *tcp_seg_copy(struct tcp_seg *seg);

#define tcp_ack(pcb)                               \
  do {                                             \
    if((pcb)->flags & TF_ACK_DELAY) {              \
      (pcb)->flags &= ~TF_ACK_DELAY;               \
      (pcb)->flags |= TF_ACK_NOW;                  \
      tcp_output(pcb);                             \
    }                                              \
    else {                                         \
      (pcb)->flags |= TF_ACK_DELAY;                \
    }                                              \
  } while (0)

#define tcp_ack_now(pcb)                           \
  do {                                             \
    (pcb)->flags |= TF_ACK_NOW;                    \
    tcp_output(pcb);                               \
  } while (0)

err_t tcp_send_ctrl(struct tcp_pcb *pcb, u8_t flags);
err_t tcp_enqueue(struct tcp_pcb *pcb, void *dataptr, u16_t len,
                  u8_t flags, u8_t apiflags, u8_t optflags);

void tcp_rexmit_seg(struct tcp_pcb *pcb, struct tcp_seg *seg);

void tcp_rst(u32_t seqno, u32_t ackno,
       struct ip_addr *local_ip, struct ip_addr *remote_ip,
       u16_t local_port, u16_t remote_port);

u32_t tcp_next_iss(void);

void tcp_keepalive(struct tcp_pcb *pcb);
void tcp_zero_window_probe(struct tcp_pcb *pcb);

#if TCP_CALCULATE_EFF_SEND_MSS
u16_t tcp_eff_send_mss(u16_t sendmss, struct ip_addr *addr);
#endif /* TCP_CALCULATE_EFF_SEND_MSS */

extern struct tcp_pcb *tcp_input_pcb;
extern u32_t tcp_ticks;

#if TCP_DEBUG || TCP_INPUT_DEBUG || TCP_OUTPUT_DEBUG
void tcp_debug_print(struct tcp_hdr *tcphdr);
void tcp_debug_print_flags(u8_t flags);
void tcp_debug_print_state(enum tcp_state s);
void tcp_debug_print_pcbs(void);
s16_t tcp_pcbs_sane(void);
#else
#  define tcp_debug_print(tcphdr)
#  define tcp_debug_print_flags(flags)
#  define tcp_debug_print_state(s)
#  define tcp_debug_print_pcbs()
#  define tcp_pcbs_sane() 1
#endif /* TCP_DEBUG */

#if NO_SYS
#define tcp_timer_needed()
#else
void tcp_timer_needed(void);
#endif

/* The TCP PCB lists. */
union tcp_listen_pcbs_t { /* List of all TCP PCBs in LISTEN state. */
  struct tcp_pcb_listen *listen_pcbs; 
  struct tcp_pcb *pcbs;
};
extern union tcp_listen_pcbs_t tcp_listen_pcbs;
extern struct tcp_pcb *tcp_active_pcbs;  /* List of all TCP PCBs that are in a
              state in which they accept or send
              data. */
extern struct tcp_pcb *tcp_tw_pcbs;      /* List of all TCP PCBs in TIME-WAIT. */

extern struct tcp_pcb *tcp_tmp_pcb;      /* Only used for temporary storage. */

/* Axioms about the above lists:   
   1) Every TCP PCB that is not CLOSED is in one of the lists.
   2) A PCB is only in one of the lists.
   3) All PCBs in the tcp_listen_pcbs list is in LISTEN state.
   4) All PCBs in the tcp_tw_pcbs list is in TIME-WAIT state.
*/

/* Define two macros, TCP_REG and TCP_RMV that registers a TCP PCB
   with a PCB list or removes a PCB from a list, respectively. */
#if 0
#define TCP_REG(pcbs, npcb) do {\
                            LWIP_DEBUGF(TCP_DEBUG, ("TCP_REG %p local port %d\n", npcb, npcb->local_port)); \
                            for(tcp_tmp_pcb = *pcbs; \
          tcp_tmp_pcb != NULL; \
        tcp_tmp_pcb = tcp_tmp_pcb->next) { \
                                LWIP_ASSERT("TCP_REG: already registered\n", tcp_tmp_pcb != npcb); \
                            } \
                            LWIP_ASSERT("TCP_REG: pcb->state != CLOSED", npcb->state != CLOSED); \
                            npcb->next = *pcbs; \
                            LWIP_ASSERT("TCP_REG: npcb->next != npcb", npcb->next != npcb); \
                            *(pcbs) = npcb; \
                            LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
              tcp_timer_needed(); \
                            } while(0)
#define TCP_RMV(pcbs, npcb) do { \
                            LWIP_ASSERT("TCP_RMV: pcbs != NULL", *pcbs != NULL); \
                            LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removing %p from %p\n", npcb, *pcbs)); \
                            if(*pcbs == npcb) { \
                               *pcbs = (*pcbs)->next; \
                            } else for(tcp_tmp_pcb = *pcbs; tcp_tmp_pcb != NULL; tcp_tmp_pcb = tcp_tmp_pcb->next) { \
                               if(tcp_tmp_pcb->next != NULL && tcp_tmp_pcb->next == npcb) { \
                                  tcp_tmp_pcb->next = npcb->next; \
                                  break; \
                               } \
                            } \
                            npcb->next = NULL; \
                            LWIP_ASSERT("TCP_RMV: tcp_pcbs sane", tcp_pcbs_sane()); \
                            LWIP_DEBUGF(TCP_DEBUG, ("TCP_RMV: removed %p from %p\n", npcb, *pcbs)); \
                            } while(0)

#else /* LWIP_DEBUG */

#define TCP_REG(pcbs, npcb)                        \
  do {                                             \
    npcb->next = *pcbs;                            \
    *(pcbs) = npcb;                                \
    tcp_timer_needed();                            \
  } while (0)

#define TCP_RMV(pcbs, npcb)                        \
  do {                                             \
    if(*(pcbs) == npcb) {                          \
      (*(pcbs)) = (*pcbs)->next;                   \
    }                                              \
    else {                                         \
      for(tcp_tmp_pcb = *pcbs;                                         \
          tcp_tmp_pcb != NULL;                                         \
          tcp_tmp_pcb = tcp_tmp_pcb->next) {                           \
        if(tcp_tmp_pcb->next != NULL && tcp_tmp_pcb->next == npcb) {   \
          tcp_tmp_pcb->next = npcb->next;          \
          break;                                   \
        }                                          \
      }                                            \
    }                                              \
    npcb->next = NULL;                             \
  } while(0)

#endif /* LWIP_DEBUG */

#ifdef __cplusplus
}
#endif

#endif /* LWIP_TCP */

#endif /* __LWIP_TCP_H__ */