text: 
  #include "lwip/opt.h"
  
  #if LWIP_SOCKET /* don't build if not configured for use in lwipopts.h */
  
  #include "lwip/sockets.h"
  #include "lwip/api.h"
  #include "lwip/sys.h"
  #include "lwip/igmp.h"
  #include "lwip/inet.h"
  #include "lwip/tcp.h"
  #include "lwip/raw.h"
  #include "lwip/udp.h"
  #include "lwip/tcpip.h"
  #include "lwip/pbuf.h"
  #if LWIP_CHECKSUM_ON_COPY
  #include "lwip/inet_chksum.h"
  #endif
  
  #include <string.h>
  
  #define NUM_SOCKETS MEMP_NUM_NETCONN
  
  /** Contains all internal pointers and states used for a socket */
  struct lwip_sock {
    /** sockets currently are built on netconns, each socket has one netconn */
    struct netconn *conn;
    /** data that was left from the previous read */
    void *lastdata;
    /** offset in the data that was left from the previous read */
    u16_t lastoffset;
    /** number of times data was received, set by event_callback(),
        tested by the receive and select functions */
    s16_t rcvevent;
    /** number of times data was ACKed (free send buffer), set by event_callback(),
        tested by select */
    u16_t sendevent;
    /** error happened for this socket, set by event_callback(), tested by select */
    u16_t errevent; 
    /** last error that occurred on this socket */
    int err;
    /** counter of how many threads are waiting for this socket using select */
    int select_waiting;
  };
  
  /** Description for a task waiting in select */
  struct lwip_select_cb {
    /** Pointer to the next waiting task */
    struct lwip_select_cb *next;
    /** Pointer to the previous waiting task */
    struct lwip_select_cb *prev;
    /** readset passed to select */
    fd_set *readset;
    /** writeset passed to select */
    fd_set *writeset;
    /** unimplemented: exceptset passed to select */
    fd_set *exceptset;
    /** don't signal the same semaphore twice: set to 1 when signalled */
    int sem_signalled;
    /** semaphore to wake up a task waiting for select */
    sys_sem_t sem;
  };
  
  /** This struct is used to pass data to the set/getsockopt_internal
   * functions running in tcpip_thread context (only a void* is allowed) */
  struct lwip_setgetsockopt_data {
    /** socket struct for which to change options */
    struct lwip_sock *sock;
  #ifdef LWIP_DEBUG
    /** socket index for which to change options */
    int s;
  #endif /* LWIP_DEBUG */
    /** level of the option to process */
    int level;
    /** name of the option to process */
    int optname;
    /** set: value to set the option to
      * get: value of the option is stored here */
    void *optval;
    /** size of *optval */
    socklen_t *optlen;
    /** if an error occures, it is temporarily stored here */
    err_t err;
  };
  
  /** The global array of available sockets */
  static struct lwip_sock sockets[NUM_SOCKETS];
  /** The global list of tasks waiting for select */
  static struct lwip_select_cb *select_cb_list;
  /** This counter is increased from lwip_select when the list is chagned
      and checked in event_callback to see if it has changed. */
  static volatile int select_cb_ctr;
  
  /** Table to quickly map an lwIP error (err_t) to a socket error
    * by using -err as an index */
  static const int err_to_errno_table[] = {
    0,             /* ERR_OK          0      No error, everything OK. */
    ENOMEM,        /* ERR_MEM        -1      Out of memory error.     */
    ENOBUFS,       /* ERR_BUF        -2      Buffer error.            */
    EWOULDBLOCK,   /* ERR_TIMEOUT    -3      Timeout                  */
    EHOSTUNREACH,  /* ERR_RTE        -4      Routing problem.         */
    EINPROGRESS,   /* ERR_INPROGRESS -5      Operation in progress    */
    EINVAL,        /* ERR_VAL        -6      Illegal value.           */
    EWOULDBLOCK,   /* ERR_WOULDBLOCK -7      Operation would block.   */
    EADDRINUSE,    /* ERR_USE        -8      Address in use.          */
    EALREADY,      /* ERR_ISCONN     -9      Already connected.       */
    ECONNABORTED,  /* ERR_ABRT       -10     Connection aborted.      */
    ECONNRESET,    /* ERR_RST        -11     Connection reset.        */
    ENOTCONN,      /* ERR_CLSD       -12     Connection closed.       */
    ENOTCONN,      /* ERR_CONN       -13     Not connected.           */
    EIO,           /* ERR_ARG        -14     Illegal argument.        */
    -1,            /* ERR_IF         -15     Low-level netif error    */
  };
  
  #define ERR_TO_ERRNO_TABLE_SIZE \
    (sizeof(err_to_errno_table)/sizeof(err_to_errno_table[0]))
  
  #define err_to_errno(err) \
    ((unsigned)(-(err)) < ERR_TO_ERRNO_TABLE_SIZE ? \
      err_to_errno_table[-(err)] : EIO)
  
  #ifdef ERRNO
  #ifndef set_errno
  #define set_errno(err) errno = (err)
  #endif
  #else /* ERRNO */
  #define set_errno(err)
  #endif /* ERRNO */
  
  #define sock_set_errno(sk, e) do { \
    sk->err = (e); \
    set_errno(sk->err); \
  } while (0)
  
  /* Forward delcaration of some functions */
  static void event_callback(struct netconn *conn, enum netconn_evt evt, u16_t len);
  static void lwip_getsockopt_internal(void *arg);
  static void lwip_setsockopt_internal(void *arg);
  
  /**
   * Initialize this module. This function has to be called before any other
   * functions in this module!
   */
  void
  lwip_socket_init(void)
  {
  }
  
  /**
   * Map a externally used socket index to the internal socket representation.
   *
   * @param s externally used socket index
   * @return struct lwip_sock for the socket or NULL if not found
   */
  static struct lwip_sock *
  get_socket(int s)
  {
    struct lwip_sock *sock;
  
    if ((s < 0) || (s >= NUM_SOCKETS)) {
      LWIP_DEBUGF(SOCKETS_DEBUG, ("get_socket(%d): invalid\n", s));
      set_errno(EBADF);
      return NULL;
    }
  
    sock = &sockets[s];
  
    if (!sock->conn) {
      LWIP_DEBUGF(SOCKETS_DEBUG, ("get_socket(%d): not active\n", s));
      set_errno(EBADF);
      return NULL;
    }
  
    return sock;
  }
  
  /**
   * Same as get_socket but doesn't set errno
   *
   * @param s externally used socket index
   * @return struct lwip_sock for the socket or NULL if not found
   */
  static struct lwip_sock *
  tryget_socket(int s)
  {
    if ((s < 0) || (s >= NUM_SOCKETS)) {
      return NULL;
    }
    if (!sockets[s].conn) {
      return NULL;
    }
    return &sockets[s];
  }
  
  /**
   * Allocate a new socket for a given netconn.
   *
   * @param newconn the netconn for which to allocate a socket
   * @param accepted 1 if socket has been created by accept(),
   *                 0 if socket has been created by socket()
   * @return the index of the new socket; -1 on error
   */
  static int
  alloc_socket(struct netconn *newconn, int accepted)
  {
    int i;
    SYS_ARCH_DECL_PROTECT(lev);
  
    /* allocate a new socket identifier */
    for (i = 0; i < NUM_SOCKETS; ++i) {
      /* Protect socket array */
      SYS_ARCH_PROTECT(lev);
      if (!sockets[i].conn) {
        sockets[i].conn       = newconn;
        /* The socket is not yet known to anyone, so no need to protect
           after having marked it as used. */
        SYS_ARCH_UNPROTECT(lev);
        sockets[i].lastdata   = NULL;
        sockets[i].lastoffset = 0;
        sockets[i].rcvevent   = 0;
        /* TCP sendbuf is empty, but the socket is not yet writable until connected
         * (unless it has been created by accept()). */
        sockets[i].sendevent  = (newconn->type == NETCONN_TCP ? (accepted != 0) : 1);
        sockets[i].errevent   = 0;
        sockets[i].err        = 0;
        sockets[i].select_waiting = 0;
        return i;
      }
      SYS_ARCH_UNPROTECT(lev);
    }
    return -1;
  }
  
  /** Free a socket. The socket's netconn must have been
   * delete before!
   *
   * @param sock the socket to free
   * @param is_tcp != 0 for TCP sockets, used to free lastdata
   */
  static void
  free_socket(struct lwip_sock *sock, int is_tcp)
  {
    void *lastdata;
    SYS_ARCH_DECL_PROTECT(lev);
  
    lastdata         = sock->lastdata;
    sock->lastdata   = NULL;
    sock->lastoffset = 0;
    sock->err        = 0;
  
    /* Protect socket array */
    SYS_ARCH_PROTECT(lev);
    sock->conn       = NULL;
    SYS_ARCH_UNPROTECT(lev);
    /* don't use 'sock' after this line, as another task might have allocated it */
  
    if (lastdata != NULL) {
      if (is_tcp) {
        pbuf_free((struct pbuf *)lastdata);
      } else {
        netbuf_delete((struct netbuf *)lastdata);
      }
    }
  }
  
  /* Below this, the well-known socket functions are implemented.
   * Use google.com or opengroup.org to get a good description :-)
   *
   * Exceptions are documented!
   */
  
  int
  lwip_accept(int s, struct sockaddr *addr, socklen_t *addrlen)
  {
    struct lwip_sock *sock, *nsock;
    struct netconn *newconn;
    ip_addr_t naddr;
    u16_t port;
    int newsock;
    struct sockaddr_in sin;
    err_t err;
    SYS_ARCH_DECL_PROTECT(lev);
  
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d)...\n", s));
    sock = get_socket(s);
    if (!sock) {
      return -1;
    }
  
    if (netconn_is_nonblocking(sock->conn) && (sock->rcvevent <= 0)) {
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d): returning EWOULDBLOCK\n", s));
      sock_set_errno(sock, EWOULDBLOCK);
      return -1;
    }
  
    /* wait for a new connection */
    err = netconn_accept(sock->conn, &newconn);
    if (err != ERR_OK) {
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d): netconn_acept failed, err=%d\n", s, err));
      if (netconn_type(sock->conn) != NETCONN_TCP) {
        sock_set_errno(sock, EOPNOTSUPP);
        return EOPNOTSUPP;
      }
      sock_set_errno(sock, err_to_errno(err));
      return -1;
    }
    LWIP_ASSERT("newconn != NULL", newconn != NULL);
    /* Prevent automatic window updates, we do this on our own! */
    netconn_set_noautorecved(newconn, 1);
  
    /* get the IP address and port of the remote host */
    err = netconn_peer(newconn, &naddr, &port);
    if (err != ERR_OK) {
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d): netconn_peer failed, err=%d\n", s, err));
      netconn_delete(newconn);
      sock_set_errno(sock, err_to_errno(err));
      return -1;
    }
  
    /* Note that POSIX only requires us to check addr is non-NULL. addrlen must
     * not be NULL if addr is valid.
     */
    if (NULL != addr) {
      LWIP_ASSERT("addr valid but addrlen NULL", addrlen != NULL);
      memset(&sin, 0, sizeof(sin));
      sin.sin_len = sizeof(sin);
      sin.sin_family = AF_INET;
      sin.sin_port = htons(port);
      inet_addr_from_ipaddr(&sin.sin_addr, &naddr);
  
      if (*addrlen > sizeof(sin))
        *addrlen = sizeof(sin);
  
      MEMCPY(addr, &sin, *addrlen);
    }
  
    newsock = alloc_socket(newconn, 1);
    if (newsock == -1) {
      netconn_delete(newconn);
      sock_set_errno(sock, ENFILE);
      return -1;
    }
    LWIP_ASSERT("invalid socket index", (newsock >= 0) && (newsock < NUM_SOCKETS));
    LWIP_ASSERT("newconn->callback == event_callback", newconn->callback == event_callback);
    nsock = &sockets[newsock];
  
    /* See event_callback: If data comes in right away after an accept, even
     * though the server task might not have created a new socket yet.
     * In that case, newconn->socket is counted down (newconn->socket--),
     * so nsock->rcvevent is >= 1 here!
     */
    SYS_ARCH_PROTECT(lev);
    nsock->rcvevent += (s16_t)(-1 - newconn->socket);
    newconn->socket = newsock;
    SYS_ARCH_UNPROTECT(lev);
  
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d) returning new sock=%d addr=", s, newsock));
    ip_addr_debug_print(SOCKETS_DEBUG, &naddr);
    LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F"\n", port));
  
    sock_set_errno(sock, 0);
    return newsock;
  }
  
  int
  lwip_bind(int s, const struct sockaddr *name, socklen_t namelen)
  {
    struct lwip_sock *sock;
    ip_addr_t local_addr;
    u16_t local_port;
    err_t err;
    const struct sockaddr_in *name_in;
  
    sock = get_socket(s);
    if (!sock) {
      return -1;
    }
  
    /* check size, familiy and alignment of 'name' */
    LWIP_ERROR("lwip_bind: invalid address", ((namelen == sizeof(struct sockaddr_in)) &&
               ((name->sa_family) == AF_INET) && ((((mem_ptr_t)name) % 4) == 0)),
               sock_set_errno(sock, err_to_errno(ERR_ARG)); return -1;);
    name_in = (const struct sockaddr_in *)(void*)name;
  
    inet_addr_to_ipaddr(&local_addr, &name_in->sin_addr);
    local_port = name_in->sin_port;
  
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_bind(%d, addr=", s));
    ip_addr_debug_print(SOCKETS_DEBUG, &local_addr);
    LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F")\n", ntohs(local_port)));
  
    err = netconn_bind(sock->conn, &local_addr, ntohs(local_port));
  
    if (err != ERR_OK) {
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_bind(%d) failed, err=%d\n", s, err));
      sock_set_errno(sock, err_to_errno(err));
      return -1;
    }
  
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_bind(%d) succeeded\n", s));
    sock_set_errno(sock, 0);
    return 0;
  }
  
  int
  lwip_close(int s)
  {
    struct lwip_sock *sock;
    int is_tcp = 0;
  
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_close(%d)\n", s));
  
    sock = get_socket(s);
    if (!sock) {
      return -1;
    }
  
    if(sock->conn != NULL) {
      is_tcp = netconn_type(sock->conn) == NETCONN_TCP;
    } else {
      LWIP_ASSERT("sock->lastdata == NULL", sock->lastdata == NULL);
    }
  
    netconn_delete(sock->conn);
  
    free_socket(sock, is_tcp);
    set_errno(0);
    return 0;
  }
  
  int
  lwip_connect(int s, const struct sockaddr *name, socklen_t namelen)
  {
    struct lwip_sock *sock;
    err_t err;
    const struct sockaddr_in *name_in;
  
    sock = get_socket(s);
    if (!sock) {
      return -1;
    }
  
    /* check size, familiy and alignment of 'name' */
    LWIP_ERROR("lwip_connect: invalid address", ((namelen == sizeof(struct sockaddr_in)) &&
               ((name->sa_family) == AF_INET) && ((((mem_ptr_t)name) % 4) == 0)),
               sock_set_errno(sock, err_to_errno(ERR_ARG)); return -1;);
    name_in = (const struct sockaddr_in *)(void*)name;
  
    if (name_in->sin_family == AF_UNSPEC) {
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_connect(%d, AF_UNSPEC)\n", s));
      err = netconn_disconnect(sock->conn);
    } else {
      ip_addr_t remote_addr;
      u16_t remote_port;
  
      inet_addr_to_ipaddr(&remote_addr, &name_in->sin_addr);
      remote_port = name_in->sin_port;
  
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_connect(%d, addr=", s));
      ip_addr_debug_print(SOCKETS_DEBUG, &remote_addr);
      LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F")\n", ntohs(remote_port)));
  
      err = netconn_connect(sock->conn, &remote_addr, ntohs(remote_port));
    }
  
    if (err != ERR_OK) {
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_connect(%d) failed, err=%d\n", s, err));
      sock_set_errno(sock, err_to_errno(err));
      return -1;
    }
  
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_connect(%d) succeeded\n", s));
    sock_set_errno(sock, 0);
    return 0;
  }
  
  /**
   * Set a socket into listen mode.
   * The socket may not have been used for another connection previously.
   *
   * @param s the socket to set to listening mode
   * @param backlog (ATTENTION: needs TCP_LISTEN_BACKLOG=1)
   * @return 0 on success, non-zero on failure
   */
  int
  lwip_listen(int s, int backlog)
  {
    struct lwip_sock *sock;
    err_t err;
  
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_listen(%d, backlog=%d)\n", s, backlog));
  
    sock = get_socket(s);
    if (!sock) {
      return -1;
    }
  
    /* limit the "backlog" parameter to fit in an u8_t */
    backlog = LWIP_MIN(LWIP_MAX(backlog, 0), 0xff);
  
    err = netconn_listen_with_backlog(sock->conn, (u8_t)backlog);
  
    if (err != ERR_OK) {
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_listen(%d) failed, err=%d\n", s, err));
      if (netconn_type(sock->conn) != NETCONN_TCP) {
        sock_set_errno(sock, EOPNOTSUPP);
        return EOPNOTSUPP;
      }
      sock_set_errno(sock, err_to_errno(err));
      return -1;
    }
  
    sock_set_errno(sock, 0);
    return 0;
  }
  
  int
  lwip_recvfrom(int s, void *mem, size_t len, int flags,
          struct sockaddr *from, socklen_t *fromlen)
  {
    struct lwip_sock *sock;
    void             *buf = NULL;
    struct pbuf      *p;
    u16_t            buflen, copylen;
    int              off = 0;
    ip_addr_t        *addr;
    u16_t            port;
    u8_t             done = 0;
    err_t            err;
  
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom(%d, %p, %"SZT_F", 0x%x, ..)\n", s, mem, len, flags));
    sock = get_socket(s);
    if (!sock) {
      return -1;
    }
  
    do {
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom: top while sock->lastdata=%p\n", sock->lastdata));
      /* Check if there is data left from the last recv operation. */
      if (sock->lastdata) {
        buf = sock->lastdata;
      } else {
        /* If this is non-blocking call, then check first */
        if (((flags & MSG_DONTWAIT) || netconn_is_nonblocking(sock->conn)) && 
            (sock->rcvevent <= 0)) {
          if (off > 0) {
            /* update receive window */
            netconn_recved(sock->conn, (u32_t)off);
            /* already received data, return that */
            sock_set_errno(sock, 0);
            return off;
          }
          LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom(%d): returning EWOULDBLOCK\n", s));
          sock_set_errno(sock, EWOULDBLOCK);
          return -1;
        }
  
        /* No data was left from the previous operation, so we try to get
           some from the network. */
        if (netconn_type(sock->conn) == NETCONN_TCP) {
          err = netconn_recv_tcp_pbuf(sock->conn, (struct pbuf **)&buf);
        } else {
          err = netconn_recv(sock->conn, (struct netbuf **)&buf);
        }
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom: netconn_recv err=%d, netbuf=%p\n",
          err, buf));
  
        if (err != ERR_OK) {
          if (off > 0) {
            /* update receive window */
            netconn_recved(sock->conn, (u32_t)off);
            /* already received data, return that */
            sock_set_errno(sock, 0);
            return off;
          }
          /* We should really do some error checking here. */
          LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom(%d): buf == NULL, error is \"%s\"!\n",
            s, lwip_strerr(err)));
          sock_set_errno(sock, err_to_errno(err));
          if (err == ERR_CLSD) {
            return 0;
          } else {
            return -1;
          }
        }
        LWIP_ASSERT("buf != NULL", buf != NULL);
        sock->lastdata = buf;
      }
  
      if (netconn_type(sock->conn) == NETCONN_TCP) {
        p = (struct pbuf *)buf;
      } else {
        p = ((struct netbuf *)buf)->p;
      }
      buflen = p->tot_len;
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom: buflen=%"U16_F" len=%"SZT_F" off=%d sock->lastoffset=%"U16_F"\n",
        buflen, len, off, sock->lastoffset));
  
      buflen -= sock->lastoffset;
  
      if (len > buflen) {
        copylen = buflen;
      } else {
        copylen = (u16_t)len;
      }
  
      /* copy the contents of the received buffer into
      the supplied memory pointer mem */
      pbuf_copy_partial(p, (u8_t*)mem + off, copylen, sock->lastoffset);
  
      off += copylen;
  
      if (netconn_type(sock->conn) == NETCONN_TCP) {
        LWIP_ASSERT("invalid copylen, len would underflow", len >= copylen);
        len -= copylen;
        if ( (len <= 0) || 
             (p->flags & PBUF_FLAG_PUSH) || 
             (sock->rcvevent <= 0) || 
             ((flags & MSG_PEEK)!=0)) {
          done = 1;
        }
      } else {
        done = 1;
      }
  
      /* Check to see from where the data was.*/
      if (done) {
        ip_addr_t fromaddr;
        if (from && fromlen) {
          struct sockaddr_in sin;
  
          if (netconn_type(sock->conn) == NETCONN_TCP) {
            addr = &fromaddr;
            netconn_getaddr(sock->conn, addr, &port, 0);
          } else {
            addr = netbuf_fromaddr((struct netbuf *)buf);
            port = netbuf_fromport((struct netbuf *)buf);
          }
  
          memset(&sin, 0, sizeof(sin));
          sin.sin_len = sizeof(sin);
          sin.sin_family = AF_INET;
          sin.sin_port = htons(port);
          inet_addr_from_ipaddr(&sin.sin_addr, addr);
  
          if (*fromlen > sizeof(sin)) {
            *fromlen = sizeof(sin);
          }
  
          MEMCPY(from, &sin, *fromlen);
  
          LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom(%d): addr=", s));
          ip_addr_debug_print(SOCKETS_DEBUG, addr);
          LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F" len=%d\n", port, off));
        } else {
  #if SOCKETS_DEBUG
          if (netconn_type(sock->conn) == NETCONN_TCP) {
            addr = &fromaddr;
            netconn_getaddr(sock->conn, addr, &port, 0);
          } else {
            addr = netbuf_fromaddr((struct netbuf *)buf);
            port = netbuf_fromport((struct netbuf *)buf);
          }
  
          LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom(%d): addr=", s));
          ip_addr_debug_print(SOCKETS_DEBUG, addr);
          LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F" len=%d\n", port, off));
  #endif /*  SOCKETS_DEBUG */
        }
      }
  
      /* If we don't peek the incoming message... */
      if ((flags & MSG_PEEK) == 0) {
        /* If this is a TCP socket, check if there is data left in the
           buffer. If so, it should be saved in the sock structure for next
           time around. */
        if ((netconn_type(sock->conn) == NETCONN_TCP) && (buflen - copylen > 0)) {
          sock->lastdata = buf;
          sock->lastoffset += copylen;
          LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom: lastdata now netbuf=%p\n", buf));
        } else {
          sock->lastdata = NULL;
          sock->lastoffset = 0;
          LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_recvfrom: deleting netbuf=%p\n", buf));
          if (netconn_type(sock->conn) == NETCONN_TCP) {
            pbuf_free((struct pbuf *)buf);
          } else {
            netbuf_delete((struct netbuf *)buf);
          }
        }
      }
    } while (!done);
  
    if (off > 0) {
      /* update receive window */
      netconn_recved(sock->conn, (u32_t)off);
    }
    sock_set_errno(sock, 0);
    return off;
  }
  
  int
  lwip_read(int s, void *mem, size_t len)
  {
    return lwip_recvfrom(s, mem, len, 0, NULL, NULL);
  }
  
  int
  lwip_recv(int s, void *mem, size_t len, int flags)
  {
    return lwip_recvfrom(s, mem, len, flags, NULL, NULL);
  }
  
  int
  lwip_send(int s, const void *data, size_t size, int flags)
  {
    struct lwip_sock *sock;
    err_t err;
    u8_t write_flags;
    size_t written;
  
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_send(%d, data=%p, size=%"SZT_F", flags=0x%x)\n",
                                s, data, size, flags));
  
    sock = get_socket(s);
    if (!sock) {
      return -1;
    }
  
    if (sock->conn->type != NETCONN_TCP) {
  #if (LWIP_UDP || LWIP_RAW)
      return lwip_sendto(s, data, size, flags, NULL, 0);
  #else /* (LWIP_UDP || LWIP_RAW) */
      sock_set_errno(sock, err_to_errno(ERR_ARG));
      return -1;
  #endif /* (LWIP_UDP || LWIP_RAW) */
    }
  
    write_flags = NETCONN_COPY |
      ((flags & MSG_MORE)     ? NETCONN_MORE      : 0) |
      ((flags & MSG_DONTWAIT) ? NETCONN_DONTBLOCK : 0);
    written = 0;
    err = netconn_write_partly(sock->conn, data, size, write_flags, &written);
  
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_send(%d) err=%d written=%"SZT_F"\n", s, err, written));
    sock_set_errno(sock, err_to_errno(err));
    return (err == ERR_OK ? (int)written : -1);
  }
  
  int
  lwip_sendto(int s, const void *data, size_t size, int flags,
         const struct sockaddr *to, socklen_t tolen)
  {
    struct lwip_sock *sock;
    err_t err;
    u16_t short_size;
    const struct sockaddr_in *to_in;
    u16_t remote_port;
  #if !LWIP_TCPIP_CORE_LOCKING
    struct netbuf buf;
  #endif
  
    sock = get_socket(s);
    if (!sock) {
      return -1;
    }
  
    if (sock->conn->type == NETCONN_TCP) {
  #if LWIP_TCP
      return lwip_send(s, data, size, flags);
  #else /* LWIP_TCP */
      LWIP_UNUSED_ARG(flags);
      sock_set_errno(sock, err_to_errno(ERR_ARG));
      return -1;
  #endif /* LWIP_TCP */
    }
  
    /* @todo: split into multiple sendto's? */
    LWIP_ASSERT("lwip_sendto: size must fit in u16_t", size <= 0xffff);
    short_size = (u16_t)size;
    LWIP_ERROR("lwip_sendto: invalid address", (((to == NULL) && (tolen == 0)) ||
               ((tolen == sizeof(struct sockaddr_in)) &&
               ((to->sa_family) == AF_INET) && ((((mem_ptr_t)to) % 4) == 0))),
               sock_set_errno(sock, err_to_errno(ERR_ARG)); return -1;);
    to_in = (const struct sockaddr_in *)(void*)to;
  
  #if LWIP_TCPIP_CORE_LOCKING
    /* Should only be consider like a sample or a simple way to experiment this option (no check of "to" field...) */
    {
      struct pbuf* p;
      ip_addr_t *remote_addr;
  
  #if LWIP_NETIF_TX_SINGLE_PBUF
      p = pbuf_alloc(PBUF_TRANSPORT, short_size, PBUF_RAM);
      if (p != NULL) {
  #if LWIP_CHECKSUM_ON_COPY
        u16_t chksum = 0;
        if (sock->conn->type != NETCONN_RAW) {
          chksum = LWIP_CHKSUM_COPY(p->payload, data, short_size);
        } else
  #endif /* LWIP_CHECKSUM_ON_COPY */
        MEMCPY(p->payload, data, size);
  #else /* LWIP_NETIF_TX_SINGLE_PBUF */
      p = pbuf_alloc(PBUF_TRANSPORT, short_size, PBUF_REF);
      if (p != NULL) {
        p->payload = (void*)data;
  #endif /* LWIP_NETIF_TX_SINGLE_PBUF */
  
        if (to_in != NULL) {
          inet_addr_to_ipaddr_p(remote_addr, &to_in->sin_addr);
          remote_port = ntohs(to_in->sin_port);
        } else {
          remote_addr = &sock->conn->pcb.ip->remote_ip;
  #if LWIP_UDP
          if (NETCONNTYPE_GROUP(sock->conn->type) == NETCONN_UDP) {
            remote_port = sock->conn->pcb.udp->remote_port;
          } else
  #endif /* LWIP_UDP */
          {
            remote_port = 0;
          }
        }
  
        LOCK_TCPIP_CORE();
        if (netconn_type(sock->conn) == NETCONN_RAW) {
  #if LWIP_RAW
          err = sock->conn->last_err = raw_sendto(sock->conn->pcb.raw, p, remote_addr);
  #else /* LWIP_RAW */
          err = ERR_ARG;
  #endif /* LWIP_RAW */
        }
  #if LWIP_UDP && LWIP_RAW
        else
  #endif /* LWIP_UDP && LWIP_RAW */
        {
  #if LWIP_UDP
  #if LWIP_CHECKSUM_ON_COPY && LWIP_NETIF_TX_SINGLE_PBUF
          err = sock->conn->last_err = udp_sendto_chksum(sock->conn->pcb.udp, p,
            remote_addr, remote_port, 1, chksum);
  #else /* LWIP_CHECKSUM_ON_COPY && LWIP_NETIF_TX_SINGLE_PBUF */
          err = sock->conn->last_err = udp_sendto(sock->conn->pcb.udp, p,
            remote_addr, remote_port);
  #endif /* LWIP_CHECKSUM_ON_COPY && LWIP_NETIF_TX_SINGLE_PBUF */
  #else /* LWIP_UDP */
          err = ERR_ARG;
  #endif /* LWIP_UDP */
        }
        UNLOCK_TCPIP_CORE();
        
        pbuf_free(p);
      } else {
        err = ERR_MEM;
      }
    }
  #else /* LWIP_TCPIP_CORE_LOCKING */
    /* initialize a buffer */
    buf.p = buf.ptr = NULL;
  #if LWIP_CHECKSUM_ON_COPY
    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;
          }
        }
        if (do_signal) {
          scb->sem_signalled = 1;
          /* Don't call SYS_ARCH_UNPROTECT() before signaling the semaphore, as this might
             lead to the select thread taking itself off the list, invalidagin the semaphore. */
          sys_sem_signal(&scb->sem);
        }
      }
      /* unlock interrupts with each step */
      last_select_cb_ctr = select_cb_ctr;
      SYS_ARCH_UNPROTECT(lev);
      /* this makes sure interrupt protection time is short */
      SYS_ARCH_PROTECT(lev);
      if (last_select_cb_ctr != select_cb_ctr) {
        /* someone has changed select_cb_list, restart at the beginning */
        goto again;
      }
    }
    SYS_ARCH_UNPROTECT(lev);
  }
  
  /**
   * Unimplemented: Close one end of a full-duplex connection.
   * Currently, the full connection is closed.
   */
  int
  lwip_shutdown(int s, int how)
  {
    struct lwip_sock *sock;
    err_t err;
    u8_t shut_rx = 0, shut_tx = 0;
  
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_shutdown(%d, how=%d)\n", s, how));
  
    sock = get_socket(s);
    if (!sock) {
      return -1;
    }
  
    if (sock->conn != NULL) {
      if (netconn_type(sock->conn) != NETCONN_TCP) {
        sock_set_errno(sock, EOPNOTSUPP);
        return EOPNOTSUPP;
      }
    } else {
      sock_set_errno(sock, ENOTCONN);
      return ENOTCONN;
    }
  
    if (how == SHUT_RD) {
      shut_rx = 1;
    } else if (how == SHUT_WR) {
      shut_tx = 1;
    } else if(how == SHUT_RDWR) {
      shut_rx = 1;
      shut_tx = 1;
    } else {
      sock_set_errno(sock, EINVAL);
      return EINVAL;
    }
    err = netconn_shutdown(sock->conn, shut_rx, shut_tx);
  
    sock_set_errno(sock, err_to_errno(err));
    return (err == ERR_OK ? 0 : -1);
  }
  
  static int
  lwip_getaddrname(int s, struct sockaddr *name, socklen_t *namelen, u8_t local)
  {
    struct lwip_sock *sock;
    struct sockaddr_in sin;
    ip_addr_t naddr;
  
    sock = get_socket(s);
    if (!sock) {
      return -1;
    }
  
    memset(&sin, 0, sizeof(sin));
    sin.sin_len = sizeof(sin);
    sin.sin_family = AF_INET;
  
    /* get the IP address and port */
    netconn_getaddr(sock->conn, &naddr, &sin.sin_port, local);
  
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getaddrname(%d, addr=", s));
    ip_addr_debug_print(SOCKETS_DEBUG, &naddr);
    LWIP_DEBUGF(SOCKETS_DEBUG, (" port=%"U16_F")\n", sin.sin_port));
  
    sin.sin_port = htons(sin.sin_port);
    inet_addr_from_ipaddr(&sin.sin_addr, &naddr);
  
    if (*namelen > sizeof(sin)) {
      *namelen = sizeof(sin);
    }
  
    MEMCPY(name, &sin, *namelen);
    sock_set_errno(sock, 0);
    return 0;
  }
  
  int
  lwip_getpeername(int s, struct sockaddr *name, socklen_t *namelen)
  {
    return lwip_getaddrname(s, name, namelen, 0);
  }
  
  int
  lwip_getsockname(int s, struct sockaddr *name, socklen_t *namelen)
  {
    return lwip_getaddrname(s, name, namelen, 1);
  }
  
  int
  lwip_getsockopt(int s, int level, int optname, void *optval, socklen_t *optlen)
  {
    err_t err = ERR_OK;
    struct lwip_sock *sock = get_socket(s);
    struct lwip_setgetsockopt_data data;
  
    if (!sock) {
      return -1;
    }
  
    if ((NULL == optval) || (NULL == optlen)) {
      sock_set_errno(sock, EFAULT);
      return -1;
    }
  
    /* Do length and type checks for the various options first, to keep it readable. */
    switch (level) {
     
  /* Level: SOL_SOCKET */
    case SOL_SOCKET:
      switch (optname) {
         
      case SO_ACCEPTCONN:
      case SO_BROADCAST:
      /* UNIMPL case SO_DEBUG: */
      /* UNIMPL case SO_DONTROUTE: */
      case SO_ERROR:
      case SO_KEEPALIVE:
      /* UNIMPL case SO_CONTIMEO: */
  #if LWIP_SO_SNDTIMEO
      case SO_SNDTIMEO:
  #endif /* LWIP_SO_SNDTIMEO */
  #if LWIP_SO_RCVTIMEO
      case SO_RCVTIMEO:
  #endif /* LWIP_SO_RCVTIMEO */
  #if LWIP_SO_RCVBUF
      case SO_RCVBUF:
  #endif /* LWIP_SO_RCVBUF */
      /* UNIMPL case SO_OOBINLINE: */
      /* UNIMPL case SO_SNDBUF: */
      /* UNIMPL case SO_RCVLOWAT: */
      /* UNIMPL case SO_SNDLOWAT: */
  #if SO_REUSE
      case SO_REUSEADDR:
      case SO_REUSEPORT:
  #endif /* SO_REUSE */
      case SO_TYPE:
      /* UNIMPL case SO_USELOOPBACK: */
        if (*optlen < sizeof(int)) {
          err = EINVAL;
        }
        break;
  
      case SO_NO_CHECK:
        if (*optlen < sizeof(int)) {
          err = EINVAL;
        }
  #if LWIP_UDP
        if ((sock->conn->type != NETCONN_UDP) ||
            ((udp_flags(sock->conn->pcb.udp) & UDP_FLAGS_UDPLITE) != 0)) {
          /* this flag is only available for UDP, not for UDP lite */
          err = EAFNOSUPPORT;
        }
  #endif /* LWIP_UDP */
        break;
  
      default:
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, SOL_SOCKET, UNIMPL: optname=0x%x, ..)\n",
                                    s, optname));
        err = ENOPROTOOPT;
      }  /* switch (optname) */
      break;
                       
  /* Level: IPPROTO_IP */
    case IPPROTO_IP:
      switch (optname) {
      /* UNIMPL case IP_HDRINCL: */
      /* UNIMPL case IP_RCVDSTADDR: */
      /* UNIMPL case IP_RCVIF: */
      case IP_TTL:
      case IP_TOS:
        if (*optlen < sizeof(int)) {
          err = EINVAL;
        }
        break;
  #if LWIP_IGMP
      case IP_MULTICAST_TTL:
        if (*optlen < sizeof(u8_t)) {
          err = EINVAL;
        }
        break;
      case IP_MULTICAST_IF:
        if (*optlen < sizeof(struct in_addr)) {
          err = EINVAL;
        }
        break;
      case IP_MULTICAST_LOOP:
        if (*optlen < sizeof(u8_t)) {
          err = EINVAL;
        }
        if (NETCONNTYPE_GROUP(sock->conn->type) != NETCONN_UDP) {
          err = EAFNOSUPPORT;
        }
        break;
  #endif /* LWIP_IGMP */
  
      default:
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, UNIMPL: optname=0x%x, ..)\n",
                                    s, optname));
        err = ENOPROTOOPT;
      }  /* switch (optname) */
      break;
           
  #if LWIP_TCP
  /* Level: IPPROTO_TCP */
    case IPPROTO_TCP:
      if (*optlen < sizeof(int)) {
        err = EINVAL;
        break;
      }
      
      /* If this is no TCP socket, ignore any options. */
      if (sock->conn->type != NETCONN_TCP)
        return 0;
  
      switch (optname) {
      case TCP_NODELAY:
      case TCP_KEEPALIVE:
  #if LWIP_TCP_KEEPALIVE
      case TCP_KEEPIDLE:
      case TCP_KEEPINTVL:
      case TCP_KEEPCNT:
  #endif /* LWIP_TCP_KEEPALIVE */
        break;
         
      default:
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_TCP, UNIMPL: optname=0x%x, ..)\n",
                                    s, optname));
        err = ENOPROTOOPT;
      }  /* switch (optname) */
      break;
  #endif /* LWIP_TCP */
  #if LWIP_UDP && LWIP_UDPLITE
  /* Level: IPPROTO_UDPLITE */
    case IPPROTO_UDPLITE:
      if (*optlen < sizeof(int)) {
        err = EINVAL;
        break;
      }
      
      /* If this is no UDP lite socket, ignore any options. */
      if (sock->conn->type != NETCONN_UDPLITE) {
        return 0;
      }
  
      switch (optname) {
      case UDPLITE_SEND_CSCOV:
      case UDPLITE_RECV_CSCOV:
        break;
         
      default:
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_UDPLITE, UNIMPL: optname=0x%x, ..)\n",
                                    s, optname));
        err = ENOPROTOOPT;
      }  /* switch (optname) */
      break;
  #endif /* LWIP_UDP && LWIP_UDPLITE*/
  /* UNDEFINED LEVEL */
    default:
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, level=0x%x, UNIMPL: optname=0x%x, ..)\n",
                                    s, level, optname));
        err = ENOPROTOOPT;
    }  /* switch */
  
     
    if (err != ERR_OK) {
      sock_set_errno(sock, err);
      return -1;
    }
  
    /* Now do the actual option processing */
    data.sock = sock;
  #ifdef LWIP_DEBUG
    data.s = s;
  #endif /* LWIP_DEBUG */
    data.level = level;
    data.optname = optname;
    data.optval = optval;
    data.optlen = optlen;
    data.err = err;
    tcpip_callback(lwip_getsockopt_internal, &data);
    sys_arch_sem_wait(&sock->conn->op_completed, 0);
    /* maybe lwip_getsockopt_internal has changed err */
    err = data.err;
  
    sock_set_errno(sock, err);
    return err ? -1 : 0;
  }
  
  static void
  lwip_getsockopt_internal(void *arg)
  {
    struct lwip_sock *sock;
  #ifdef LWIP_DEBUG
    int s;
  #endif /* LWIP_DEBUG */
    int level, optname;
    void *optval;
    struct lwip_setgetsockopt_data *data;
  
    LWIP_ASSERT("arg != NULL", arg != NULL);
  
    data = (struct lwip_setgetsockopt_data*)arg;
    sock = data->sock;
  #ifdef LWIP_DEBUG
    s = data->s;
  #endif /* LWIP_DEBUG */
    level = data->level;
    optname = data->optname;
    optval = data->optval;
  
    switch (level) {
  
  /* Level: SOL_SOCKET */
    case SOL_SOCKET:
      switch (optname) {
  
      /* The option flags */
      case SO_ACCEPTCONN:
      case SO_BROADCAST:
      /* UNIMPL case SO_DEBUG: */
      /* UNIMPL case SO_DONTROUTE: */
      case SO_KEEPALIVE:
      /* UNIMPL case SO_OOBINCLUDE: */
  #if SO_REUSE
      case SO_REUSEADDR:
      case SO_REUSEPORT:
  #endif /* SO_REUSE */
      /*case SO_USELOOPBACK: UNIMPL */
        *(int*)optval = ip_get_option(sock->conn->pcb.ip, optname);
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, SOL_SOCKET, optname=0x%x, ..) = %s\n",
                                    s, optname, (*(int*)optval?"on":"off")));
        break;
  
      case SO_TYPE:
        switch (NETCONNTYPE_GROUP(sock->conn->type)) {
        case NETCONN_RAW:
          *(int*)optval = SOCK_RAW;
          break;
        case NETCONN_TCP:
          *(int*)optval = SOCK_STREAM;
          break;
        case NETCONN_UDP:
          *(int*)optval = SOCK_DGRAM;
          break;
        default: /* unrecognized socket type */
          *(int*)optval = sock->conn->type;
          LWIP_DEBUGF(SOCKETS_DEBUG,
                      ("lwip_getsockopt(%d, SOL_SOCKET, SO_TYPE): unrecognized socket type %d\n",
                      s, *(int *)optval));
        }  /* switch (sock->conn->type) */
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, SOL_SOCKET, SO_TYPE) = %d\n",
                    s, *(int *)optval));
        break;
  
      case SO_ERROR:
        /* only overwrite ERR_OK or tempoary errors */
        if ((sock->err == 0) || (sock->err == EINPROGRESS)) {
          sock_set_errno(sock, err_to_errno(sock->conn->last_err));
        } 
        *(int *)optval = sock->err;
        sock->err = 0;
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, SOL_SOCKET, SO_ERROR) = %d\n",
                    s, *(int *)optval));
        break;
  
  #if LWIP_SO_SNDTIMEO
      case SO_SNDTIMEO:
        *(int *)optval = netconn_get_sendtimeout(sock->conn);
        break;
  #endif /* LWIP_SO_SNDTIMEO */
  #if LWIP_SO_RCVTIMEO
      case SO_RCVTIMEO:
        *(int *)optval = netconn_get_recvtimeout(sock->conn);
        break;
  #endif /* LWIP_SO_RCVTIMEO */
  #if LWIP_SO_RCVBUF
      case SO_RCVBUF:
        *(int *)optval = netconn_get_recvbufsize(sock->conn);
        break;
  #endif /* LWIP_SO_RCVBUF */
  #if LWIP_UDP
      case SO_NO_CHECK:
        *(int*)optval = (udp_flags(sock->conn->pcb.udp) & UDP_FLAGS_NOCHKSUM) ? 1 : 0;
        break;
  #endif /* LWIP_UDP*/
      default:
        LWIP_ASSERT("unhandled optname", 0);
        break;
      }  /* switch (optname) */
      break;
  
  /* Level: IPPROTO_IP */
    case IPPROTO_IP:
      switch (optname) {
      case IP_TTL:
        *(int*)optval = sock->conn->pcb.ip->ttl;
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, IP_TTL) = %d\n",
                    s, *(int *)optval));
        break;
      case IP_TOS:
        *(int*)optval = sock->conn->pcb.ip->tos;
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, IP_TOS) = %d\n",
                    s, *(int *)optval));
        break;
  #if LWIP_IGMP
      case IP_MULTICAST_TTL:
        *(u8_t*)optval = sock->conn->pcb.ip->ttl;
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, IP_MULTICAST_TTL) = %d\n",
                    s, *(int *)optval));
        break;
      case IP_MULTICAST_IF:
        inet_addr_from_ipaddr((struct in_addr*)optval, &sock->conn->pcb.udp->multicast_ip);
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, IP_MULTICAST_IF) = 0x%"X32_F"\n",
                    s, *(u32_t *)optval));
        break;
      case IP_MULTICAST_LOOP:
        if ((sock->conn->pcb.udp->flags & UDP_FLAGS_MULTICAST_LOOP) != 0) {
          *(u8_t*)optval = 1;
        } else {
          *(u8_t*)optval = 0;
        }
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, IP_MULTICAST_LOOP) = %d\n",
                    s, *(int *)optval));
        break;
  #endif /* LWIP_IGMP */
      default:
        LWIP_ASSERT("unhandled optname", 0);
        break;
      }  /* switch (optname) */
      break;
  
  #if LWIP_TCP
  /* Level: IPPROTO_TCP */
    case IPPROTO_TCP:
      switch (optname) {
      case TCP_NODELAY:
        *(int*)optval = tcp_nagle_disabled(sock->conn->pcb.tcp);
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_TCP, TCP_NODELAY) = %s\n",
                    s, (*(int*)optval)?"on":"off") );
        break;
      case TCP_KEEPALIVE:
        *(int*)optval = (int)sock->conn->pcb.tcp->keep_idle;
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, TCP_KEEPALIVE) = %d\n",
                    s, *(int *)optval));
        break;
  
  #if LWIP_TCP_KEEPALIVE
      case TCP_KEEPIDLE:
        *(int*)optval = (int)(sock->conn->pcb.tcp->keep_idle/1000);
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, TCP_KEEPIDLE) = %d\n",
                    s, *(int *)optval));
        break;
      case TCP_KEEPINTVL:
        *(int*)optval = (int)(sock->conn->pcb.tcp->keep_intvl/1000);
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, TCP_KEEPINTVL) = %d\n",
                    s, *(int *)optval));
        break;
      case TCP_KEEPCNT:
        *(int*)optval = (int)sock->conn->pcb.tcp->keep_cnt;
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_IP, TCP_KEEPCNT) = %d\n",
                    s, *(int *)optval));
        break;
  #endif /* LWIP_TCP_KEEPALIVE */
      default:
        LWIP_ASSERT("unhandled optname", 0);
        break;
      }  /* switch (optname) */
      break;
  #endif /* LWIP_TCP */
  #if LWIP_UDP && LWIP_UDPLITE
    /* Level: IPPROTO_UDPLITE */
    case IPPROTO_UDPLITE:
      switch (optname) {
      case UDPLITE_SEND_CSCOV:
        *(int*)optval = sock->conn->pcb.udp->chksum_len_tx;
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_UDPLITE, UDPLITE_SEND_CSCOV) = %d\n",
                    s, (*(int*)optval)) );
        break;
      case UDPLITE_RECV_CSCOV:
        *(int*)optval = sock->conn->pcb.udp->chksum_len_rx;
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_getsockopt(%d, IPPROTO_UDPLITE, UDPLITE_RECV_CSCOV) = %d\n",
                    s, (*(int*)optval)) );
        break;
      default:
        LWIP_ASSERT("unhandled optname", 0);
        break;
      }  /* switch (optname) */
      break;
  #endif /* LWIP_UDP */
    default:
      LWIP_ASSERT("unhandled level", 0);
      break;
    } /* switch (level) */
    sys_sem_signal(&sock->conn->op_completed);
  }
  
  int
  lwip_setsockopt(int s, int level, int optname, const void *optval, socklen_t optlen)
  {
    struct lwip_sock *sock = get_socket(s);
    err_t err = ERR_OK;
    struct lwip_setgetsockopt_data data;
  
    if (!sock) {
      return -1;
    }
  
    if (NULL == optval) {
      sock_set_errno(sock, EFAULT);
      return -1;
    }
  
    /* Do length and type checks for the various options first, to keep it readable. */
    switch (level) {
  
  /* Level: SOL_SOCKET */
    case SOL_SOCKET:
      switch (optname) {
  
      case SO_BROADCAST:
      /* UNIMPL case SO_DEBUG: */
      /* UNIMPL case SO_DONTROUTE: */
      case SO_KEEPALIVE:
      /* UNIMPL case case SO_CONTIMEO: */
  #if LWIP_SO_SNDTIMEO
      case SO_SNDTIMEO:
  #endif /* LWIP_SO_SNDTIMEO */
  #if LWIP_SO_RCVTIMEO
      case SO_RCVTIMEO:
  #endif /* LWIP_SO_RCVTIMEO */
  #if LWIP_SO_RCVBUF
      case SO_RCVBUF:
  #endif /* LWIP_SO_RCVBUF */
      /* UNIMPL case SO_OOBINLINE: */
      /* UNIMPL case SO_SNDBUF: */
      /* UNIMPL case SO_RCVLOWAT: */
      /* UNIMPL case SO_SNDLOWAT: */
  #if SO_REUSE
      case SO_REUSEADDR:
      case SO_REUSEPORT:
  #endif /* SO_REUSE */
      /* UNIMPL case SO_USELOOPBACK: */
        if (optlen < sizeof(int)) {
          err = EINVAL;
        }
        break;
      case SO_NO_CHECK:
        if (optlen < sizeof(int)) {
          err = EINVAL;
        }
  #if LWIP_UDP
        if ((sock->conn->type != NETCONN_UDP) ||
            ((udp_flags(sock->conn->pcb.udp) & UDP_FLAGS_UDPLITE) != 0)) {
          /* this flag is only available for UDP, not for UDP lite */
          err = EAFNOSUPPORT;
        }
  #endif /* LWIP_UDP */
        break;
      default:
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, SOL_SOCKET, UNIMPL: optname=0x%x, ..)\n",
                    s, optname));
        err = ENOPROTOOPT;
      }  /* switch (optname) */
      break;
  
  /* Level: IPPROTO_IP */
    case IPPROTO_IP:
      switch (optname) {
      /* UNIMPL case IP_HDRINCL: */
      /* UNIMPL case IP_RCVDSTADDR: */
      /* UNIMPL case IP_RCVIF: */
      case IP_TTL:
      case IP_TOS:
        if (optlen < sizeof(int)) {
          err = EINVAL;
        }
        break;
  #if LWIP_IGMP
      case IP_MULTICAST_TTL:
        if (optlen < sizeof(u8_t)) {
          err = EINVAL;
        }
        if (NETCONNTYPE_GROUP(sock->conn->type) != NETCONN_UDP) {
          err = EAFNOSUPPORT;
        }
        break;
      case IP_MULTICAST_IF:
        if (optlen < sizeof(struct in_addr)) {
          err = EINVAL;
        }
        if (NETCONNTYPE_GROUP(sock->conn->type) != NETCONN_UDP) {
          err = EAFNOSUPPORT;
        }
        break;
      case IP_MULTICAST_LOOP:
        if (optlen < sizeof(u8_t)) {
          err = EINVAL;
        }
        if (NETCONNTYPE_GROUP(sock->conn->type) != NETCONN_UDP) {
          err = EAFNOSUPPORT;
        }
        break;
      case IP_ADD_MEMBERSHIP:
      case IP_DROP_MEMBERSHIP:
        if (optlen < sizeof(struct ip_mreq)) {
          err = EINVAL;
        }
        if (NETCONNTYPE_GROUP(sock->conn->type) != NETCONN_UDP) {
          err = EAFNOSUPPORT;
        }
        break;
  #endif /* LWIP_IGMP */
        default:
          LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_IP, UNIMPL: optname=0x%x, ..)\n",
                      s, optname));
          err = ENOPROTOOPT;
      }  /* switch (optname) */
      break;
  
  #if LWIP_TCP
  /* Level: IPPROTO_TCP */
    case IPPROTO_TCP:
      if (optlen < sizeof(int)) {
        err = EINVAL;
        break;
      }
  
      /* If this is no TCP socket, ignore any options. */
      if (sock->conn->type != NETCONN_TCP)
        return 0;
  
      switch (optname) {
      case TCP_NODELAY:
      case TCP_KEEPALIVE:
  #if LWIP_TCP_KEEPALIVE
      case TCP_KEEPIDLE:
      case TCP_KEEPINTVL:
      case TCP_KEEPCNT:
  #endif /* LWIP_TCP_KEEPALIVE */
        break;
  
      default:
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_TCP, UNIMPL: optname=0x%x, ..)\n",
                    s, optname));
        err = ENOPROTOOPT;
      }  /* switch (optname) */
      break;
  #endif /* LWIP_TCP */
  #if LWIP_UDP && LWIP_UDPLITE
  /* Level: IPPROTO_UDPLITE */
    case IPPROTO_UDPLITE:
      if (optlen < sizeof(int)) {
        err = EINVAL;
        break;
      }
  
      /* If this is no UDP lite socket, ignore any options. */
      if (sock->conn->type != NETCONN_UDPLITE)
        return 0;
  
      switch (optname) {
      case UDPLITE_SEND_CSCOV:
      case UDPLITE_RECV_CSCOV:
        break;
  
      default:
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_UDPLITE, UNIMPL: optname=0x%x, ..)\n",
                    s, optname));
        err = ENOPROTOOPT;
      }  /* switch (optname) */
      break;
  #endif /* LWIP_UDP && LWIP_UDPLITE */
  /* UNDEFINED LEVEL */
    default:
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, level=0x%x, UNIMPL: optname=0x%x, ..)\n",
                  s, level, optname));
      err = ENOPROTOOPT;
    }  /* switch (level) */
  
  
    if (err != ERR_OK) {
      sock_set_errno(sock, err);
      return -1;
    }
  
  
    /* Now do the actual option processing */
    data.sock = sock;
  #ifdef LWIP_DEBUG
    data.s = s;
  #endif /* LWIP_DEBUG */
    data.level = level;
    data.optname = optname;
    data.optval = (void*)optval;
    data.optlen = &optlen;
    data.err = err;
    tcpip_callback(lwip_setsockopt_internal, &data);
    sys_arch_sem_wait(&sock->conn->op_completed, 0);
    /* maybe lwip_setsockopt_internal has changed err */
    err = data.err;
  
    sock_set_errno(sock, err);
    return err ? -1 : 0;
  }
  
  static void
  lwip_setsockopt_internal(void *arg)
  {
    struct lwip_sock *sock;
  #ifdef LWIP_DEBUG
    int s;
  #endif /* LWIP_DEBUG */
    int level, optname;
    const void *optval;
    struct lwip_setgetsockopt_data *data;
  
    LWIP_ASSERT("arg != NULL", arg != NULL);
  
    data = (struct lwip_setgetsockopt_data*)arg;
    sock = data->sock;
  #ifdef LWIP_DEBUG
    s = data->s;
  #endif /* LWIP_DEBUG */
    level = data->level;
    optname = data->optname;
    optval = data->optval;
  
    switch (level) {
  
  /* Level: SOL_SOCKET */
    case SOL_SOCKET:
      switch (optname) {
  
      /* The option flags */
      case SO_BROADCAST:
      /* UNIMPL case SO_DEBUG: */
      /* UNIMPL case SO_DONTROUTE: */
      case SO_KEEPALIVE:
      /* UNIMPL case SO_OOBINCLUDE: */
  #if SO_REUSE
      case SO_REUSEADDR:
      case SO_REUSEPORT:
  #endif /* SO_REUSE */
      /* UNIMPL case SO_USELOOPBACK: */
        if (*(int*)optval) {
          ip_set_option(sock->conn->pcb.ip, optname);
        } else {
          ip_reset_option(sock->conn->pcb.ip, optname);
        }
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, SOL_SOCKET, optname=0x%x, ..) -> %s\n",
                    s, optname, (*(int*)optval?"on":"off")));
        break;
  #if LWIP_SO_SNDTIMEO
      case SO_SNDTIMEO:
        netconn_set_sendtimeout(sock->conn, (s32_t)*(int*)optval);
        break;
  #endif /* LWIP_SO_SNDTIMEO */
  #if LWIP_SO_RCVTIMEO
      case SO_RCVTIMEO:
        netconn_set_recvtimeout(sock->conn, *(int*)optval);
        break;
  #endif /* LWIP_SO_RCVTIMEO */
  #if LWIP_SO_RCVBUF
      case SO_RCVBUF:
        netconn_set_recvbufsize(sock->conn, *(int*)optval);
        break;
  #endif /* LWIP_SO_RCVBUF */
  #if LWIP_UDP
      case SO_NO_CHECK:
        if (*(int*)optval) {
          udp_setflags(sock->conn->pcb.udp, udp_flags(sock->conn->pcb.udp) | UDP_FLAGS_NOCHKSUM);
        } else {
          udp_setflags(sock->conn->pcb.udp, udp_flags(sock->conn->pcb.udp) & ~UDP_FLAGS_NOCHKSUM);
        }
        break;
  #endif /* LWIP_UDP */
      default:
        LWIP_ASSERT("unhandled optname", 0);
        break;
      }  /* switch (optname) */
      break;
  
  /* Level: IPPROTO_IP */
    case IPPROTO_IP:
      switch (optname) {
      case IP_TTL:
        sock->conn->pcb.ip->ttl = (u8_t)(*(int*)optval);
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_IP, IP_TTL, ..) -> %d\n",
                    s, sock->conn->pcb.ip->ttl));
        break;
      case IP_TOS:
        sock->conn->pcb.ip->tos = (u8_t)(*(int*)optval);
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_IP, IP_TOS, ..)-> %d\n",
                    s, sock->conn->pcb.ip->tos));
        break;
  #if LWIP_IGMP
      case IP_MULTICAST_TTL:
        sock->conn->pcb.udp->ttl = (u8_t)(*(u8_t*)optval);
        break;
      case IP_MULTICAST_IF:
        inet_addr_to_ipaddr(&sock->conn->pcb.udp->multicast_ip, (struct in_addr*)optval);
        break;
      case IP_MULTICAST_LOOP:
        if (*(u8_t*)optval) {
          udp_setflags(sock->conn->pcb.udp, udp_flags(sock->conn->pcb.udp) | UDP_FLAGS_MULTICAST_LOOP);
        } else {
          udp_setflags(sock->conn->pcb.udp, udp_flags(sock->conn->pcb.udp) & ~UDP_FLAGS_MULTICAST_LOOP);
        }
        break;
      case IP_ADD_MEMBERSHIP:
      case IP_DROP_MEMBERSHIP:
        {
          /* If this is a TCP or a RAW socket, ignore these options. */
          struct ip_mreq *imr = (struct ip_mreq *)optval;
          ip_addr_t if_addr;
          ip_addr_t multi_addr;
          inet_addr_to_ipaddr(&if_addr, &imr->imr_interface);
          inet_addr_to_ipaddr(&multi_addr, &imr->imr_multiaddr);
          if(optname == IP_ADD_MEMBERSHIP){
            data->err = igmp_joingroup(&if_addr, &multi_addr);
          } else {
            data->err = igmp_leavegroup(&if_addr, &multi_addr);
          }
          if(data->err != ERR_OK) {
            data->err = EADDRNOTAVAIL;
          }
        }
        break;
  #endif /* LWIP_IGMP */
      default:
        LWIP_ASSERT("unhandled optname", 0);
        break;
      }  /* switch (optname) */
      break;
  
  #if LWIP_TCP
  /* Level: IPPROTO_TCP */
    case IPPROTO_TCP:
      switch (optname) {
      case TCP_NODELAY:
        if (*(int*)optval) {
          tcp_nagle_disable(sock->conn->pcb.tcp);
        } else {
          tcp_nagle_enable(sock->conn->pcb.tcp);
        }
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_TCP, TCP_NODELAY) -> %s\n",
                    s, (*(int *)optval)?"on":"off") );
        break;
      case TCP_KEEPALIVE:
        sock->conn->pcb.tcp->keep_idle = (u32_t)(*(int*)optval);
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_TCP, TCP_KEEPALIVE) -> %"U32_F"\n",
                    s, sock->conn->pcb.tcp->keep_idle));
        break;
  
  #if LWIP_TCP_KEEPALIVE
      case TCP_KEEPIDLE:
        sock->conn->pcb.tcp->keep_idle = 1000*(u32_t)(*(int*)optval);
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_TCP, TCP_KEEPIDLE) -> %"U32_F"\n",
                    s, sock->conn->pcb.tcp->keep_idle));
        break;
      case TCP_KEEPINTVL:
        sock->conn->pcb.tcp->keep_intvl = 1000*(u32_t)(*(int*)optval);
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_TCP, TCP_KEEPINTVL) -> %"U32_F"\n",
                    s, sock->conn->pcb.tcp->keep_intvl));
        break;
      case TCP_KEEPCNT:
        sock->conn->pcb.tcp->keep_cnt = (u32_t)(*(int*)optval);
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_TCP, TCP_KEEPCNT) -> %"U32_F"\n",
                    s, sock->conn->pcb.tcp->keep_cnt));
        break;
  #endif /* LWIP_TCP_KEEPALIVE */
      default:
        LWIP_ASSERT("unhandled optname", 0);
        break;
      }  /* switch (optname) */
      break;
  #endif /* LWIP_TCP*/
  #if LWIP_UDP && LWIP_UDPLITE
    /* Level: IPPROTO_UDPLITE */
    case IPPROTO_UDPLITE:
      switch (optname) {
      case UDPLITE_SEND_CSCOV:
        if ((*(int*)optval != 0) && ((*(int*)optval < 8) || (*(int*)optval > 0xffff))) {
          /* don't allow illegal values! */
          sock->conn->pcb.udp->chksum_len_tx = 8;
        } else {
          sock->conn->pcb.udp->chksum_len_tx = (u16_t)*(int*)optval;
        }
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_UDPLITE, UDPLITE_SEND_CSCOV) -> %d\n",
                    s, (*(int*)optval)) );
        break;
      case UDPLITE_RECV_CSCOV:
        if ((*(int*)optval != 0) && ((*(int*)optval < 8) || (*(int*)optval > 0xffff))) {
          /* don't allow illegal values! */
          sock->conn->pcb.udp->chksum_len_rx = 8;
        } else {
          sock->conn->pcb.udp->chksum_len_rx = (u16_t)*(int*)optval;
        }
        LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_UDPLITE, UDPLITE_RECV_CSCOV) -> %d\n",
                    s, (*(int*)optval)) );
        break;
      default:
        LWIP_ASSERT("unhandled optname", 0);
        break;
      }  /* switch (optname) */
      break;
  #endif /* LWIP_UDP */
    default:
      LWIP_ASSERT("unhandled level", 0);
      break;
    }  /* switch (level) */
    sys_sem_signal(&sock->conn->op_completed);
  }
  
  int
  lwip_ioctl(int s, long cmd, void *argp)
  {
    struct lwip_sock *sock = get_socket(s);
    u8_t val;
  #if LWIP_SO_RCVBUF
    u16_t buflen = 0;
    s16_t recv_avail;
  #endif /* LWIP_SO_RCVBUF */
  
    if (!sock) {
      return -1;
    }
  
    switch (cmd) {
  #if LWIP_SO_RCVBUF
    case FIONREAD:
      if (!argp) {
        sock_set_errno(sock, EINVAL);
        return -1;
      }
  
      SYS_ARCH_GET(sock->conn->recv_avail, recv_avail);
      if (recv_avail < 0) {
        recv_avail = 0;
      }
      *((u16_t*)argp) = (u16_t)recv_avail;
  
      /* Check if there is data left from the last recv operation. /maq 041215 */
      if (sock->lastdata) {
        struct pbuf *p = (struct pbuf *)sock->lastdata;
        if (netconn_type(sock->conn) != NETCONN_TCP) {
          p = ((struct netbuf *)p)->p;
        }
        buflen = p->tot_len;
        buflen -= sock->lastoffset;
  
        *((u16_t*)argp) += buflen;
      }
  
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_ioctl(%d, FIONREAD, %p) = %"U16_F"\n", s, argp, *((u16_t*)argp)));
      sock_set_errno(sock, 0);
      return 0;
  #endif /* LWIP_SO_RCVBUF */
  
    case FIONBIO:
      val = 0;
      if (argp && *(u32_t*)argp) {
        val = 1;
      }
      netconn_set_nonblocking(sock->conn, val);
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_ioctl(%d, FIONBIO, %d)\n", s, val));
      sock_set_errno(sock, 0);
      return 0;
  
    default:
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_ioctl(%d, UNIMPL: 0x%lx, %p)\n", s, cmd, argp));
      sock_set_errno(sock, ENOSYS); /* not yet implemented */
      return -1;
    } /* switch (cmd) */
  }
  
  /** A minimal implementation of fcntl.
   * Currently only the commands F_GETFL and F_SETFL are implemented.
   * Only the flag O_NONBLOCK is implemented.
   */
  int
  lwip_fcntl(int s, int cmd, int val)
  {
    struct lwip_sock *sock = get_socket(s);
    int ret = -1;
  
    if (!sock || !sock->conn) {
      return -1;
    }
  
    switch (cmd) {
    case F_GETFL:
      ret = netconn_is_nonblocking(sock->conn) ? O_NONBLOCK : 0;
      break;
    case F_SETFL:
      if ((val & ~O_NONBLOCK) == 0) {
        /* only O_NONBLOCK, all other bits are zero */
        netconn_set_nonblocking(sock->conn, val & O_NONBLOCK);
        ret = 0;
      }
      break;
    default:
      LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_fcntl(%d, UNIMPL: %d, %d)\n", s, cmd, val));
      break;
    }
    return ret;
  }
  
  #endif /* LWIP_SOCKET */
  