Diff: src/api/sockets.c

Revision:

0:8e01dca41002

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/api/sockets.c	Thu May 24 15:53:48 2012 +0000
@@ -0,0 +1,2347 @@
+/**
+ * @file
+ * Sockets BSD-Like API module
+ *
+ */
+
+/*
+ * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
+ * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
+ * OF SUCH DAMAGE.
+ *
+ * This file is part of the lwIP TCP/IP stack.
+ *
+ * Author: Adam Dunkels <adam@sics.se>
+ *
+ * Improved by Marc Boucher <marc@mbsi.ca> and David Haas <dhaas@alum.rpi.edu>
+ *
+ */
+
+#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));
+    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));
+    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;
+
+  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) */
+  }
+
+  if ((flags & MSG_DONTWAIT) || netconn_is_nonblocking(sock->conn)) {
+    if ((size > TCP_SND_BUF) || ((size / TCP_MSS) > TCP_SND_QUEUELEN)) {
+      /* too much data to ever send nonblocking! */
+      sock_set_errno(sock, EMSGSIZE);
+      return -1;
+    }
+  }
+
+  write_flags = NETCONN_COPY |
+    ((flags & MSG_MORE)     ? NETCONN_MORE      : 0) |
+    ((flags & MSG_DONTWAIT) ? NETCONN_DONTBLOCK : 0);
+  err = netconn_write(sock->conn, data, size, write_flags);
+
+  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_send(%d) err=%d size=%"SZT_F"\n", s, err, size));
+  sock_set_errno(sock, err_to_errno(err));
+  return (err == ERR_OK ? (int)size : -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.raw->remote_ip;
+        if (sock->conn->type == NETCONN_RAW) {
+          remote_port = 0;
+        } else {
+          remote_port = sock->conn->pcb.udp->remote_port;
+        }
+      }
+
+      LOCK_TCPIP_CORE();
+      if (sock->conn->type == NETCONN_RAW) {
+        err = sock->conn->last_err = raw_sendto(sock->conn->pcb.raw, p, remote_addr);
+      } else {
+#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: */
+    /* UNIMPL case 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 = sock->conn->pcb.ip->so_options & 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_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: */
+    /* UNIMPL case case 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) {
+        sock->conn->pcb.ip->so_options |= optname;
+      } else {
+        sock->conn->pcb.ip->so_options &= ~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_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 */