tcp_impl.h

lwip-1.4.0

  do {                                                           \
    if(((pcb)->recv != NULL)) {                                  \
      (ret) = (pcb)->recv((pcb)->callback_arg,(pcb),NULL,ERR_OK);\
    } else {                                                     \
      (ret) = ERR_OK;                                            \
    }                                                            \
  } 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 */

/** Enabled extra-check for TCP_OVERSIZE if LWIP_DEBUG is enabled */
#if TCP_OVERSIZE && defined(LWIP_DEBUG)
#define TCP_OVERSIZE_DBGCHECK 1
#else
#define TCP_OVERSIZE_DBGCHECK 0
#endif

/** Don't generate checksum on copy if CHECKSUM_GEN_TCP is disabled */
#define TCP_CHECKSUM_ON_COPY  (LWIP_CHECKSUM_ON_COPY && CHECKSUM_GEN_TCP)

/* This structure represents a TCP segment on the unsent, unacked and ooseq queues */
struct tcp_seg {
  struct tcp_seg *next;    /* used when putting segements on a queue */
  struct pbuf *p;          /* buffer containing data + TCP header */
  u16_t len;               /* the TCP length of this segment */
#if TCP_OVERSIZE_DBGCHECK
  u16_t oversize_left;     /* Extra bytes available at the end of the last
                              pbuf in unsent (used for asserting vs.
                              tcp_pcb.unsent_oversized only) */
#endif /* TCP_OVERSIZE_DBGCHECK */ 
#if TCP_CHECKSUM_ON_COPY
  u16_t chksum;
  u8_t  chksum_swapped;
#endif /* TCP_CHECKSUM_ON_COPY */
  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. */
#define TF_SEG_DATA_CHECKSUMMED (u8_t)0x04U /* ALL data (not the header) is
                                               checksummed into 'chksum' */
  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) = PP_HTONL(((u32_t)2 << 24) |          \
                                               ((u32_t)4 << 16) |          \
                                               (((u32_t)TCP_MSS / 256) << 8) | \
                                               (TCP_MSS & 255))

/* Global variables: */
extern struct tcp_pcb *tcp_input_pcb;
extern u32_t tcp_ticks;

/* 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 struct tcp_pcb *tcp_bound_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. */
#ifndef TCP_DEBUG_PCB_LISTS
#define TCP_DEBUG_PCB_LISTS 0
#endif
#if TCP_DEBUG_PCB_LISTS
#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", ((pcbs) == &tcp_bound_pcbs) || ((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 == (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 == (npcb)) {          \
          tcp_tmp_pcb->next = (npcb)->next;        \
          break;                                   \
        }                                          \
      }                                            \
    }                                              \
    (npcb)->next = NULL;                           \
  } while(0)

#endif /* LWIP_DEBUG */


/* Internal functions: */
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);

void tcp_segs_free(struct tcp_seg *seg);
void 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;                  \
    }                                              \
    else {                                         \
      (pcb)->flags |= TF_ACK_DELAY;                \
    }                                              \
  } while (0)

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

err_t tcp_send_fin(struct tcp_pcb *pcb);
err_t tcp_enqueue_flags(struct tcp_pcb *pcb, u8_t flags);

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

void tcp_rst(u32_t seqno, u32_t ackno,
       ip_addr_t *local_ip, ip_addr_t *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, ip_addr_t *addr);
#endif /* TCP_CALCULATE_EFF_SEND_MSS */

#if LWIP_CALLBACK_API
err_t tcp_recv_null(void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err);
#endif /* LWIP_CALLBACK_API */

#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 */

/** External function (implemented in timers.c), called when TCP detects
 * that a timer is needed (i.e. active- or time-wait-pcb found). */
void tcp_timer_needed(void);


#ifdef __cplusplus
}
#endif

#endif /* LWIP_TCP */

#endif /* __LWIP_TCP_H__ */