sockets.c

lwip-1.4.0

  buf.flags = 0;
#endif /* LWIP_CHECKSUM_ON_COPY */
  if (to) {
    inet_addr_to_ipaddr(&buf.addr, &to_in->sin_addr);
    remote_port           = ntohs(to_in->sin_port);
    netbuf_fromport(&buf) = remote_port;
  } else {
    remote_port           = 0;
    ip_addr_set_any(&buf.addr);
    netbuf_fromport(&buf) = 0;
  }

  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_sendto(%d, data=%p, short_size=%"U16_F", flags=0x%x to=",
              s, data, short_size, flags));
  ip_addr_debug_print(SOCKETS_DEBUG, &buf.addr);
  LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F"\n", remote_port));

  /* make the buffer point to the data that should be sent */
#if LWIP_NETIF_TX_SINGLE_PBUF
  /* Allocate a new netbuf and copy the data into it. */
  if (netbuf_alloc(&buf, short_size) == NULL) {
    err = ERR_MEM;
  } else {
#if LWIP_CHECKSUM_ON_COPY
    if (sock->conn->type != NETCONN_RAW) {
      u16_t chksum = LWIP_CHKSUM_COPY(buf.p->payload, data, short_size);
      netbuf_set_chksum(&buf, chksum);
      err = ERR_OK;
    } else
#endif /* LWIP_CHECKSUM_ON_COPY */
    {
      err = netbuf_take(&buf, data, short_size);
    }
  }
#else /* LWIP_NETIF_TX_SINGLE_PBUF */
  err = netbuf_ref(&buf, data, short_size);
#endif /* LWIP_NETIF_TX_SINGLE_PBUF */
  if (err == ERR_OK) {
    /* send the data */
    err = netconn_send(sock->conn, &buf);
  }

  /* deallocated the buffer */
  netbuf_free(&buf);
#endif /* LWIP_TCPIP_CORE_LOCKING */
  sock_set_errno(sock, err_to_errno(err));
  return (err == ERR_OK ? short_size : -1);
}

int
lwip_socket(int domain, int type, int protocol)
{
  struct netconn *conn;
  int i;

  LWIP_UNUSED_ARG(domain);

  /* create a netconn */
  switch (type) {
  case SOCK_RAW:
    conn = netconn_new_with_proto_and_callback(NETCONN_RAW, (u8_t)protocol, event_callback);
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_socket(%s, SOCK_RAW, %d) = ",
                                 domain == PF_INET ? "PF_INET" : "UNKNOWN", protocol));
    break;
  case SOCK_DGRAM:
    conn = netconn_new_with_callback( (protocol == IPPROTO_UDPLITE) ?
                 NETCONN_UDPLITE : NETCONN_UDP, event_callback);
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_socket(%s, SOCK_DGRAM, %d) = ",
                                 domain == PF_INET ? "PF_INET" : "UNKNOWN", protocol));
    break;
  case SOCK_STREAM:
    conn = netconn_new_with_callback(NETCONN_TCP, event_callback);
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_socket(%s, SOCK_STREAM, %d) = ",
                                 domain == PF_INET ? "PF_INET" : "UNKNOWN", protocol));
    if (conn != NULL) {
      /* Prevent automatic window updates, we do this on our own! */
      netconn_set_noautorecved(conn, 1);
    }
    break;
  default:
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_socket(%d, %d/UNKNOWN, %d) = -1\n",
                                 domain, type, protocol));
    set_errno(EINVAL);
    return -1;
  }

  if (!conn) {
    LWIP_DEBUGF(SOCKETS_DEBUG, ("-1 / ENOBUFS (could not create netconn)\n"));
    set_errno(ENOBUFS);
    return -1;
  }

  i = alloc_socket(conn, 0);

  if (i == -1) {
    netconn_delete(conn);
    set_errno(ENFILE);
    return -1;
  }
  conn->socket = i;
  LWIP_DEBUGF(SOCKETS_DEBUG, ("%d\n", i));
  set_errno(0);
  return i;
}

int
lwip_write(int s, const void *data, size_t size)
{
  return lwip_send(s, data, size, 0);
}

/**
 * Go through the readset and writeset lists and see which socket of the sockets
 * set in the sets has events. On return, readset, writeset and exceptset have
 * the sockets enabled that had events.
 *
 * exceptset is not used for now!!!
 *
 * @param maxfdp1 the highest socket index in the sets
 * @param readset_in:    set of sockets to check for read events
 * @param writeset_in:   set of sockets to check for write events
 * @param exceptset_in:  set of sockets to check for error events
 * @param readset_out:   set of sockets that had read events
 * @param writeset_out:  set of sockets that had write events
 * @param exceptset_out: set os sockets that had error events
 * @return number of sockets that had events (read/write/exception) (>= 0)
 */
static int
lwip_selscan(int maxfdp1, fd_set *readset_in, fd_set *writeset_in, fd_set *exceptset_in,
             fd_set *readset_out, fd_set *writeset_out, fd_set *exceptset_out)
{
  int i, nready = 0;
  fd_set lreadset, lwriteset, lexceptset;
  struct lwip_sock *sock;
  SYS_ARCH_DECL_PROTECT(lev);

  FD_ZERO(&lreadset);
  FD_ZERO(&lwriteset);
  FD_ZERO(&lexceptset);

  /* Go through each socket in each list to count number of sockets which
     currently match */
  for(i = 0; i < maxfdp1; i++) {
    void* lastdata = NULL;
    s16_t rcvevent = 0;
    u16_t sendevent = 0;
    u16_t errevent = 0;
    /* First get the socket's status (protected)... */
    SYS_ARCH_PROTECT(lev);
    sock = tryget_socket(i);
    if (sock != NULL) {
      lastdata = sock->lastdata;
      rcvevent = sock->rcvevent;
      sendevent = sock->sendevent;
      errevent = sock->errevent;
    }
    SYS_ARCH_UNPROTECT(lev);
    /* ... then examine it: */
    /* See if netconn of this socket is ready for read */
    if (readset_in && FD_ISSET(i, readset_in) && ((lastdata != NULL) || (rcvevent > 0))) {
      FD_SET(i, &lreadset);
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_selscan: fd=%d ready for reading\n", i));
      nready++;
    }
    /* See if netconn of this socket is ready for write */
    if (writeset_in && FD_ISSET(i, writeset_in) && (sendevent != 0)) {
      FD_SET(i, &lwriteset);
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_selscan: fd=%d ready for writing\n", i));
      nready++;
    }
    /* See if netconn of this socket had an error */
    if (exceptset_in && FD_ISSET(i, exceptset_in) && (errevent != 0)) {
      FD_SET(i, &lexceptset);
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_selscan: fd=%d ready for exception\n", i));
      nready++;
    }
  }
  /* copy local sets to the ones provided as arguments */
  *readset_out = lreadset;
  *writeset_out = lwriteset;
  *exceptset_out = lexceptset;

  LWIP_ASSERT("nready >= 0", nready >= 0);
  return nready;
}

/**
 * Processing exceptset is not yet implemented.
 */
int
lwip_select(int maxfdp1, fd_set *readset, fd_set *writeset, fd_set *exceptset,
            struct timeval *timeout)
{
  u32_t waitres = 0;
  int nready;
  fd_set lreadset, lwriteset, lexceptset;
  u32_t msectimeout;
  struct lwip_select_cb select_cb;
  err_t err;
  int i;
  SYS_ARCH_DECL_PROTECT(lev);

  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_select(%d, %p, %p, %p, tvsec=%"S32_F" tvusec=%"S32_F")\n",
                  maxfdp1, (void *)readset, (void *) writeset, (void *) exceptset,
                  timeout ? (s32_t)timeout->tv_sec : (s32_t)-1,
                  timeout ? (s32_t)timeout->tv_usec : (s32_t)-1));

  /* Go through each socket in each list to count number of sockets which
     currently match */
  nready = lwip_selscan(maxfdp1, readset, writeset, exceptset, &lreadset, &lwriteset, &lexceptset);

  /* If we don't have any current events, then suspend if we are supposed to */
  if (!nready) {
    if (timeout && timeout->tv_sec == 0 && timeout->tv_usec == 0) {
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_select: no timeout, returning 0\n"));
      /* This is OK as the local fdsets are empty and nready is zero,
         or we would have returned earlier. */
      goto return_copy_fdsets;
    }

    /* None ready: add our semaphore to list:
       We don't actually need any dynamic memory. Our entry on the
       list is only valid while we are in this function, so it's ok
       to use local variables. */

    select_cb.next = NULL;
    select_cb.prev = NULL;
    select_cb.readset = readset;
    select_cb.writeset = writeset;
    select_cb.exceptset = exceptset;
    select_cb.sem_signalled = 0;
    err = sys_sem_new(&select_cb.sem, 0);
    if (err != ERR_OK) {
      /* failed to create semaphore */
      set_errno(ENOMEM);
      return -1;
    }

    /* Protect the select_cb_list */
    SYS_ARCH_PROTECT(lev);

    /* Put this select_cb on top of list */
    select_cb.next = select_cb_list;
    if (select_cb_list != NULL) {
      select_cb_list->prev = &select_cb;
    }
    select_cb_list = &select_cb;
    /* Increasing this counter tells even_callback that the list has changed. */
    select_cb_ctr++;

    /* Now we can safely unprotect */
    SYS_ARCH_UNPROTECT(lev);

    /* Increase select_waiting for each socket we are interested in */
    for(i = 0; i < maxfdp1; i++) {
      if ((readset && FD_ISSET(i, readset)) ||
          (writeset && FD_ISSET(i, writeset)) ||
          (exceptset && FD_ISSET(i, exceptset))) {
        struct lwip_sock *sock = tryget_socket(i);
        LWIP_ASSERT("sock != NULL", sock != NULL);
        SYS_ARCH_PROTECT(lev);
        sock->select_waiting++;
        LWIP_ASSERT("sock->select_waiting > 0", sock->select_waiting > 0);
        SYS_ARCH_UNPROTECT(lev);
      }
    }

    /* Call lwip_selscan again: there could have been events between
       the last scan (whithout us on the list) and putting us on the list! */
    nready = lwip_selscan(maxfdp1, readset, writeset, exceptset, &lreadset, &lwriteset, &lexceptset);
    if (!nready) {
      /* Still none ready, just wait to be woken */
      if (timeout == 0) {
        /* Wait forever */
        msectimeout = 0;
      } else {
        msectimeout =  ((timeout->tv_sec * 1000) + ((timeout->tv_usec + 500)/1000));
        if (msectimeout == 0) {
          /* Wait 1ms at least (0 means wait forever) */
          msectimeout = 1;
        }
      }

      waitres = sys_arch_sem_wait(&select_cb.sem, msectimeout);
    }
    /* Increase select_waiting for each socket we are interested in */
    for(i = 0; i < maxfdp1; i++) {
      if ((readset && FD_ISSET(i, readset)) ||
          (writeset && FD_ISSET(i, writeset)) ||
          (exceptset && FD_ISSET(i, exceptset))) {
        struct lwip_sock *sock = tryget_socket(i);
        LWIP_ASSERT("sock != NULL", sock != NULL);
        SYS_ARCH_PROTECT(lev);
        sock->select_waiting--;
        LWIP_ASSERT("sock->select_waiting >= 0", sock->select_waiting >= 0);
        SYS_ARCH_UNPROTECT(lev);
      }
    }
    /* Take us off the list */
    SYS_ARCH_PROTECT(lev);
    if (select_cb.next != NULL) {
      select_cb.next->prev = select_cb.prev;
    }
    if (select_cb_list == &select_cb) {
      LWIP_ASSERT("select_cb.prev == NULL", select_cb.prev == NULL);
      select_cb_list = select_cb.next;
    } else {
      LWIP_ASSERT("select_cb.prev != NULL", select_cb.prev != NULL);
      select_cb.prev->next = select_cb.next;
    }
    /* Increasing this counter tells even_callback that the list has changed. */
    select_cb_ctr++;
    SYS_ARCH_UNPROTECT(lev);

    sys_sem_free(&select_cb.sem);
    if (waitres == SYS_ARCH_TIMEOUT)  {
      /* Timeout */
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_select: timeout expired\n"));
      /* This is OK as the local fdsets are empty and nready is zero,
         or we would have returned earlier. */
      goto return_copy_fdsets;
    }

    /* See what's set */
    nready = lwip_selscan(maxfdp1, readset, writeset, exceptset, &lreadset, &lwriteset, &lexceptset);
  }

  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_select: nready=%d\n", nready));
return_copy_fdsets:
  set_errno(0);
  if (readset) {
    *readset = lreadset;
  }
  if (writeset) {
    *writeset = lwriteset;
  }
  if (exceptset) {
    *exceptset = lexceptset;
  }


  return nready;
}

/**
 * Callback registered in the netconn layer for each socket-netconn.
 * Processes recvevent (data available) and wakes up tasks waiting for select.
 */
static void
event_callback(struct netconn *conn, enum netconn_evt evt, u16_t len)
{
  int s;
  struct lwip_sock *sock;
  struct lwip_select_cb *scb;
  int last_select_cb_ctr;
  SYS_ARCH_DECL_PROTECT(lev);

  LWIP_UNUSED_ARG(len);

  /* Get socket */
  if (conn) {
    s = conn->socket;
    if (s < 0) {
      /* Data comes in right away after an accept, even though
       * the server task might not have created a new socket yet.
       * Just count down (or up) if that's the case and we
       * will use the data later. Note that only receive events
       * can happen before the new socket is set up. */
      SYS_ARCH_PROTECT(lev);
      if (conn->socket < 0) {
        if (evt == NETCONN_EVT_RCVPLUS) {
          conn->socket--;
        }
        SYS_ARCH_UNPROTECT(lev);
        return;
      }
      s = conn->socket;
      SYS_ARCH_UNPROTECT(lev);
    }

    sock = get_socket(s);
    if (!sock) {
      return;
    }
  } else {
    return;
  }

  SYS_ARCH_PROTECT(lev);
  /* Set event as required */
  switch (evt) {
    case NETCONN_EVT_RCVPLUS:
      sock->rcvevent++;
      break;
    case NETCONN_EVT_RCVMINUS:
      sock->rcvevent--;
      break;
    case NETCONN_EVT_SENDPLUS:
      sock->sendevent = 1;
      break;
    case NETCONN_EVT_SENDMINUS:
      sock->sendevent = 0;
      break;
    case NETCONN_EVT_ERROR:
      sock->errevent = 1;
      break;
    default:
      LWIP_ASSERT("unknown event", 0);
      break;
  }

  if (sock->select_waiting == 0) {
    /* noone is waiting for this socket, no need to check select_cb_list */
    SYS_ARCH_UNPROTECT(lev);
    return;
  }

  /* Now decide if anyone is waiting for this socket */
  /* NOTE: This code goes through the select_cb_list list multiple times
     ONLY IF a select was actually waiting. We go through the list the number
     of waiting select calls + 1. This list is expected to be small. */

  /* At this point, SYS_ARCH is still protected! */
again:
  for (scb = select_cb_list; scb != NULL; scb = scb->next) {
    if (scb->sem_signalled == 0) {
      /* semaphore not signalled yet */
      int do_signal = 0;
      /* Test this select call for our socket */
      if (sock->rcvevent > 0) {
        if (scb->readset && FD_ISSET(s, scb->readset)) {
          do_signal = 1;
        }
      }
      if (sock->sendevent != 0) {
        if (!do_signal && scb->writeset && FD_ISSET(s, scb->writeset)) {
          do_signal = 1;
        }
      }
      if (sock->errevent != 0) {
        if (!do_signal && scb->exceptset && FD_ISSET(s, scb->exceptset)) {
          do_signal = 1;