diff --git a/CHANGELOG b/CHANGELOG
index 300b3d50..8d6c2333 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -6,6 +6,10 @@ HISTORY
 
  ++ New features:
 
+  2014-02-20: Simon Goldschmidt (based on patch by Artem Pisarenko)
+  * patch #7885: modification of api modules to support FreeRTOS-MPU
+    (don't pass stack-pointers to other threads)
+
   2014-02-05: Simon Goldschmidt (patch by "xtian" and "alex_ab")
   * patch #6537/#7858: TCP window scaling support
 
diff --git a/src/api/api_lib.c b/src/api/api_lib.c
index adaaad43..971fe918 100644
--- a/src/api/api_lib.c
+++ b/src/api/api_lib.c
@@ -54,6 +54,12 @@
 
 #include <string.h>
 
+#define API_MSG_VAR_REF(name)             API_VAR_REF(name)
+#define API_MSG_VAR_DECLARE(name)         API_VAR_DECLARE(struct api_msg, name)
+#define API_MSG_VAR_ALLOC(name)           API_VAR_ALLOC(struct api_msg, MEMP_API_MSG, name)
+#define API_MSG_VAR_ALLOC_DONTFAIL(name)  API_VAR_ALLOC_DONTFAIL(struct api_msg, MEMP_API_MSG, name)
+#define API_MSG_VAR_FREE(name)            API_VAR_FREE(MEMP_API_MSG, name)
+
 /**
  * Create a new netconn (of a specific type) that has a callback function.
  * The corresponding pcb is also created.
@@ -68,14 +74,16 @@ struct netconn*
 netconn_new_with_proto_and_callback(enum netconn_type t, u8_t proto, netconn_callback callback)
 {
   struct netconn *conn;
-  struct api_msg msg;
+  API_MSG_VAR_DECLARE(msg);
 
   conn = netconn_alloc(t, callback);
   if (conn != NULL) {
     err_t err;
-    msg.msg.msg.n.proto = proto;
-    msg.msg.conn = conn;
-    TCPIP_APIMSG((&msg), lwip_netconn_do_newconn, err);
+    API_MSG_VAR_ALLOC_DONTFAIL(msg);
+    API_MSG_VAR_REF(msg).msg.msg.n.proto = proto;
+    API_MSG_VAR_REF(msg).msg.conn = conn;
+    TCPIP_APIMSG(&API_MSG_VAR_REF(msg), lwip_netconn_do_newconn, err);
+    API_MSG_VAR_FREE(msg);
     if (err != ERR_OK) {
       LWIP_ASSERT("freeing conn without freeing pcb", conn->pcb.tcp == NULL);
       LWIP_ASSERT("conn has no op_completed", sys_sem_valid(&conn->op_completed));
@@ -103,16 +111,18 @@ netconn_new_with_proto_and_callback(enum netconn_type t, u8_t proto, netconn_cal
 err_t
 netconn_delete(struct netconn *conn)
 {
-  struct api_msg msg;
+  API_MSG_VAR_DECLARE(msg);
 
   /* No ASSERT here because possible to get a (conn == NULL) if we got an accept error */
   if (conn == NULL) {
     return ERR_OK;
   }
 
-  msg.function = lwip_netconn_do_delconn;
-  msg.msg.conn = conn;
-  tcpip_apimsg(&msg);
+  API_MSG_VAR_ALLOC(msg);
+  API_MSG_VAR_REF(msg).function = lwip_netconn_do_delconn;
+  API_MSG_VAR_REF(msg).msg.conn = conn;
+  tcpip_apimsg(&API_MSG_VAR_REF(msg));
+  API_MSG_VAR_FREE(msg);
 
   netconn_free(conn);
 
@@ -135,18 +145,26 @@ netconn_delete(struct netconn *conn)
 err_t
 netconn_getaddr(struct netconn *conn, ip_addr_t *addr, u16_t *port, u8_t local)
 {
-  struct api_msg msg;
+  API_MSG_VAR_DECLARE(msg);
   err_t err;
 
   LWIP_ERROR("netconn_getaddr: invalid conn", (conn != NULL), return ERR_ARG;);
   LWIP_ERROR("netconn_getaddr: invalid addr", (addr != NULL), return ERR_ARG;);
   LWIP_ERROR("netconn_getaddr: invalid port", (port != NULL), return ERR_ARG;);
 
-  msg.msg.conn = conn;
+  API_MSG_VAR_ALLOC(msg);
+  API_MSG_VAR_REF(msg).msg.conn = conn;
+  API_MSG_VAR_REF(msg).msg.msg.ad.local = local;
+#if LWIP_MPU_COMPATIBLE
+  TCPIP_APIMSG(msg, lwip_netconn_do_getaddr, err);
+  *addr = *ipX_2_ip(&(msg->msg.msg.ad.ipaddr));
+  *port = msg->msg.msg.ad.port;
+#else /* LWIP_MPU_COMPATIBLE */
   msg.msg.msg.ad.ipaddr = ip_2_ipX(addr);
   msg.msg.msg.ad.port = port;
-  msg.msg.msg.ad.local = local;
   TCPIP_APIMSG(&msg, lwip_netconn_do_getaddr, err);
+#endif /* LWIP_MPU_COMPATIBLE */
+  API_MSG_VAR_FREE(msg);
 
   NETCONN_SET_SAFE_ERR(conn, err);
   return err;
@@ -165,15 +183,22 @@ netconn_getaddr(struct netconn *conn, ip_addr_t *addr, u16_t *port, u8_t local)
 err_t
 netconn_bind(struct netconn *conn, ip_addr_t *addr, u16_t port)
 {
-  struct api_msg msg;
+  API_MSG_VAR_DECLARE(msg);
   err_t err;
 
   LWIP_ERROR("netconn_bind: invalid conn", (conn != NULL), return ERR_ARG;);
 
-  msg.msg.conn = conn;
-  msg.msg.msg.bc.ipaddr = addr;
-  msg.msg.msg.bc.port = port;
-  TCPIP_APIMSG(&msg, lwip_netconn_do_bind, err);
+  API_MSG_VAR_ALLOC(msg);
+#if LWIP_MPU_COMPATIBLE
+  if (addr == NULL) {
+    addr = IP_ADDR_ANY;
+  }
+#endif /* LWIP_MPU_COMPATIBLE */
+  API_MSG_VAR_REF(msg).msg.conn = conn;
+  API_MSG_VAR_REF(msg).msg.msg.bc.ipaddr = API_MSG_VAR_REF(addr);
+  API_MSG_VAR_REF(msg).msg.msg.bc.port = port;
+  TCPIP_APIMSG(&API_MSG_VAR_REF(msg), lwip_netconn_do_bind, err);
+  API_MSG_VAR_FREE(msg);
 
   NETCONN_SET_SAFE_ERR(conn, err);
   return err;
@@ -190,14 +215,20 @@ netconn_bind(struct netconn *conn, ip_addr_t *addr, u16_t port)
 err_t
 netconn_connect(struct netconn *conn, ip_addr_t *addr, u16_t port)
 {
-  struct api_msg msg;
+  API_MSG_VAR_DECLARE(msg);
   err_t err;
 
   LWIP_ERROR("netconn_connect: invalid conn", (conn != NULL), return ERR_ARG;);
 
-  msg.msg.conn = conn;
-  msg.msg.msg.bc.ipaddr = addr;
-  msg.msg.msg.bc.port = port;
+  API_MSG_VAR_ALLOC(msg);
+#if LWIP_MPU_COMPATIBLE
+  if (addr == NULL) {
+    addr = IP_ADDR_ANY;
+  }
+#endif /* LWIP_MPU_COMPATIBLE */
+  API_MSG_VAR_REF(msg).msg.conn = conn;
+  API_MSG_VAR_REF(msg).msg.msg.bc.ipaddr = API_MSG_VAR_REF(addr);
+  API_MSG_VAR_REF(msg).msg.msg.bc.port = port;
 #if LWIP_TCP
 #if (LWIP_UDP || LWIP_RAW)
   if (NETCONNTYPE_GROUP(conn->type) == NETCONN_TCP)
@@ -205,8 +236,8 @@ netconn_connect(struct netconn *conn, ip_addr_t *addr, u16_t port)
   {
     /* The TCP version waits for the connect to succeed,
        so always needs to use message passing. */
-    msg.function = lwip_netconn_do_connect;
-    err = tcpip_apimsg(&msg);
+    API_MSG_VAR_REF(msg).function = lwip_netconn_do_connect;
+    err = tcpip_apimsg(&API_MSG_VAR_REF(msg));
   }
 #endif /* LWIP_TCP */
 #if (LWIP_UDP || LWIP_RAW) && LWIP_TCP
@@ -215,9 +246,10 @@ netconn_connect(struct netconn *conn, ip_addr_t *addr, u16_t port)
 #if (LWIP_UDP || LWIP_RAW)
   {
      /* UDP and RAW only set flags, so we can use core-locking. */
-     TCPIP_APIMSG(&msg, lwip_netconn_do_connect, err);
+     TCPIP_APIMSG(&API_MSG_VAR_REF(msg), lwip_netconn_do_connect, err);
   }
 #endif /* (LWIP_UDP || LWIP_RAW) */
+  API_MSG_VAR_FREE(msg);
 
   NETCONN_SET_SAFE_ERR(conn, err);
   return err;
@@ -232,13 +264,15 @@ netconn_connect(struct netconn *conn, ip_addr_t *addr, u16_t port)
 err_t
 netconn_disconnect(struct netconn *conn)
 {
-  struct api_msg msg;
+  API_MSG_VAR_DECLARE(msg);
   err_t err;
 
   LWIP_ERROR("netconn_disconnect: invalid conn", (conn != NULL), return ERR_ARG;);
 
-  msg.msg.conn = conn;
-  TCPIP_APIMSG(&msg, lwip_netconn_do_disconnect, err);
+  API_MSG_VAR_ALLOC(msg);
+  API_MSG_VAR_REF(msg).msg.conn = conn;
+  TCPIP_APIMSG(&API_MSG_VAR_REF(msg), lwip_netconn_do_disconnect, err);
+  API_MSG_VAR_FREE(msg);
 
   NETCONN_SET_SAFE_ERR(conn, err);
   return err;
@@ -256,7 +290,7 @@ err_t
 netconn_listen_with_backlog(struct netconn *conn, u8_t backlog)
 {
 #if LWIP_TCP
-  struct api_msg msg;
+  API_MSG_VAR_DECLARE(msg);
   err_t err;
 
   /* This does no harm. If TCP_LISTEN_BACKLOG is off, backlog is unused. */
@@ -264,11 +298,13 @@ netconn_listen_with_backlog(struct netconn *conn, u8_t backlog)
 
   LWIP_ERROR("netconn_listen: invalid conn", (conn != NULL), return ERR_ARG;);
 
-  msg.msg.conn = conn;
+  API_MSG_VAR_ALLOC(msg);
+  API_MSG_VAR_REF(msg).msg.conn = conn;
 #if TCP_LISTEN_BACKLOG
-  msg.msg.msg.lb.backlog = backlog;
+  API_MSG_VAR_REF(msg).msg.msg.lb.backlog = backlog;
 #endif /* TCP_LISTEN_BACKLOG */
-  TCPIP_APIMSG(&msg, lwip_netconn_do_listen, err);
+  TCPIP_APIMSG(&API_MSG_VAR_REF(msg), lwip_netconn_do_listen, err);
+  API_MSG_VAR_FREE(msg);
 
   NETCONN_SET_SAFE_ERR(conn, err);
   return err;
@@ -294,7 +330,7 @@ netconn_accept(struct netconn *conn, struct netconn **new_conn)
   struct netconn *newconn;
   err_t err;
 #if TCP_LISTEN_BACKLOG
-  struct api_msg msg;
+  API_MSG_VAR_DECLARE(msg);
 #endif /* TCP_LISTEN_BACKLOG */
 
   LWIP_ERROR("netconn_accept: invalid pointer",    (new_conn != NULL),                  return ERR_ARG;);
@@ -327,9 +363,11 @@ netconn_accept(struct netconn *conn, struct netconn **new_conn)
   }
 #if TCP_LISTEN_BACKLOG
   /* Let the stack know that we have accepted the connection. */
-  msg.msg.conn = conn;
+  API_MSG_VAR_ALLOC_DONTFAIL(msg);
+  API_MSG_VAR_REF(msg).msg.conn = conn;
   /* don't care for the return value of lwip_netconn_do_recv */
-  TCPIP_APIMSG_NOERR(&msg, lwip_netconn_do_recv);
+  TCPIP_APIMSG_NOERR(&API_MSG_VAR_REF(msg), lwip_netconn_do_recv);
+  API_MSG_VAR_FREE(msg);
 #endif /* TCP_LISTEN_BACKLOG */
 
   *new_conn = newconn;
@@ -358,7 +396,7 @@ netconn_recv_data(struct netconn *conn, void **new_buf)
   u16_t len;
   err_t err;
 #if LWIP_TCP
-  struct api_msg msg;
+  API_MSG_VAR_DECLARE(msg);
 #endif /* LWIP_TCP */
 
   LWIP_ERROR("netconn_recv: invalid pointer", (new_buf != NULL), return ERR_ARG;);
@@ -393,14 +431,16 @@ netconn_recv_data(struct netconn *conn, void **new_buf)
       /* Let the stack know that we have taken the data. */
       /* TODO: Speedup: Don't block and wait for the answer here
          (to prevent multiple thread-switches). */
-      msg.msg.conn = conn;
+      API_MSG_VAR_ALLOC_DONTFAIL(msg);
+      API_MSG_VAR_REF(msg).msg.conn = conn;
       if (buf != NULL) {
-        msg.msg.msg.r.len = ((struct pbuf *)buf)->tot_len;
+        API_MSG_VAR_REF(msg).msg.msg.r.len = ((struct pbuf *)buf)->tot_len;
       } else {
-        msg.msg.msg.r.len = 1;
+        API_MSG_VAR_REF(msg).msg.msg.r.len = 1;
       }
       /* don't care for the return value of lwip_netconn_do_recv */
-      TCPIP_APIMSG_NOERR(&msg, lwip_netconn_do_recv);
+      TCPIP_APIMSG_NOERR(&API_MSG_VAR_REF(msg), lwip_netconn_do_recv);
+      API_MSG_VAR_FREE(msg);
     }
 
     /* If we are closed, we indicate that we no longer wish to use the socket */
@@ -531,14 +571,16 @@ netconn_recved(struct netconn *conn, u32_t length)
 #if LWIP_TCP
   if ((conn != NULL) && (NETCONNTYPE_GROUP(conn->type) == NETCONN_TCP) &&
       (netconn_get_noautorecved(conn))) {
-    struct api_msg msg;
+    API_MSG_VAR_DECLARE(msg);
     /* Let the stack know that we have taken the data. */
     /* TODO: Speedup: Don't block and wait for the answer here
        (to prevent multiple thread-switches). */
-    msg.msg.conn = conn;
-    msg.msg.msg.r.len = length;
+    API_MSG_VAR_ALLOC_DONTFAIL(msg);
+    API_MSG_VAR_REF(msg).msg.conn = conn;
+    API_MSG_VAR_REF(msg).msg.msg.r.len = length;
     /* don't care for the return value of lwip_netconn_do_recv */
-    TCPIP_APIMSG_NOERR(&msg, lwip_netconn_do_recv);
+    TCPIP_APIMSG_NOERR(&API_MSG_VAR_REF(msg), lwip_netconn_do_recv);
+    API_MSG_VAR_FREE(msg);
   }
 #else /* LWIP_TCP */
   LWIP_UNUSED_ARG(conn);
@@ -577,15 +619,17 @@ netconn_sendto(struct netconn *conn, struct netbuf *buf, ip_addr_t *addr, u16_t
 err_t
 netconn_send(struct netconn *conn, struct netbuf *buf)
 {
-  struct api_msg msg;
+  API_MSG_VAR_DECLARE(msg);
   err_t err;
 
   LWIP_ERROR("netconn_send: invalid conn",  (conn != NULL), return ERR_ARG;);
 
   LWIP_DEBUGF(API_LIB_DEBUG, ("netconn_send: sending %"U16_F" bytes\n", buf->p->tot_len));
-  msg.msg.conn = conn;
-  msg.msg.msg.b = buf;
-  TCPIP_APIMSG(&msg, lwip_netconn_do_send, err);
+  API_MSG_VAR_ALLOC(msg);
+  API_MSG_VAR_REF(msg).msg.conn = conn;
+  API_MSG_VAR_REF(msg).msg.msg.b = buf;
+  TCPIP_APIMSG(&API_MSG_VAR_REF(msg), lwip_netconn_do_send, err);
+  API_MSG_VAR_FREE(msg);
 
   NETCONN_SET_SAFE_ERR(conn, err);
   return err;
@@ -608,7 +652,7 @@ err_t
 netconn_write_partly(struct netconn *conn, const void *dataptr, size_t size,
                      u8_t apiflags, size_t *bytes_written)
 {
-  struct api_msg msg;
+  API_MSG_VAR_DECLARE(msg);
   err_t err;
   u8_t dontblock;
 
@@ -624,25 +668,26 @@ netconn_write_partly(struct netconn *conn, const void *dataptr, size_t size,
     return ERR_VAL;
   }
 
+  API_MSG_VAR_ALLOC(msg);
   /* non-blocking write sends as much  */
-  msg.msg.conn = conn;
-  msg.msg.msg.w.dataptr = dataptr;
-  msg.msg.msg.w.apiflags = apiflags;
-  msg.msg.msg.w.len = size;
+  API_MSG_VAR_REF(msg).msg.conn = conn;
+  API_MSG_VAR_REF(msg).msg.msg.w.dataptr = dataptr;
+  API_MSG_VAR_REF(msg).msg.msg.w.apiflags = apiflags;
+  API_MSG_VAR_REF(msg).msg.msg.w.len = size;
 #if LWIP_SO_SNDTIMEO
   if (conn->send_timeout != 0) {
     /* get the time we started, which is later compared to
         sys_now() + conn->send_timeout */
-    msg.msg.msg.w.time_started = sys_now();
+    API_MSG_VAR_REF(msg).msg.msg.w.time_started = sys_now();
   } else {
-    msg.msg.msg.w.time_started = 0;
+    API_MSG_VAR_REF(msg).msg.msg.w.time_started = 0;
   }
 #endif /* LWIP_SO_SNDTIMEO */
 
   /* For locking the core: this _can_ be delayed on low memory/low send buffer,
      but if it is, this is done inside api_msg.c:do_write(), so we can use the
      non-blocking version here. */
-  TCPIP_APIMSG(&msg, lwip_netconn_do_write, err);
+  TCPIP_APIMSG(&API_MSG_VAR_REF(msg), lwip_netconn_do_write, err);
   if ((err == ERR_OK) && (bytes_written != NULL)) {
     if (dontblock
 #if LWIP_SO_SNDTIMEO
@@ -650,12 +695,13 @@ netconn_write_partly(struct netconn *conn, const void *dataptr, size_t size,
 #endif /* LWIP_SO_SNDTIMEO */
        ) {
       /* nonblocking write: maybe the data has been sent partly */
-      *bytes_written = msg.msg.msg.w.len;
+      *bytes_written = API_MSG_VAR_REF(msg).msg.msg.w.len;
     } else {
       /* blocking call succeeded: all data has been sent if it */
       *bytes_written = size;
     }
   }
+  API_MSG_VAR_FREE(msg);
 
   NETCONN_SET_SAFE_ERR(conn, err);
   return err;
@@ -671,18 +717,20 @@ netconn_write_partly(struct netconn *conn, const void *dataptr, size_t size,
 static err_t
 netconn_close_shutdown(struct netconn *conn, u8_t how)
 {
-  struct api_msg msg;
+  API_MSG_VAR_DECLARE(msg);
   err_t err;
 
   LWIP_ERROR("netconn_close: invalid conn",  (conn != NULL), return ERR_ARG;);
 
-  msg.function = lwip_netconn_do_close;
-  msg.msg.conn = conn;
+  API_MSG_VAR_ALLOC(msg);
+  API_MSG_VAR_REF(msg).function = lwip_netconn_do_close;
+  API_MSG_VAR_REF(msg).msg.conn = conn;
   /* shutting down both ends is the same as closing */
-  msg.msg.msg.sd.shut = how;
+  API_MSG_VAR_REF(msg).msg.msg.sd.shut = how;
   /* because of the LWIP_TCPIP_CORE_LOCKING implementation of lwip_netconn_do_close,
      don't use TCPIP_APIMSG here */
-  err = tcpip_apimsg(&msg);
+  err = tcpip_apimsg(&API_MSG_VAR_REF(msg));
+  API_MSG_VAR_FREE(msg);
 
   NETCONN_SET_SAFE_ERR(conn, err);
   return err;
@@ -730,16 +778,26 @@ netconn_join_leave_group(struct netconn *conn,
                          ip_addr_t *netif_addr,
                          enum netconn_igmp join_or_leave)
 {
-  struct api_msg msg;
+  API_MSG_VAR_DECLARE(msg);
   err_t err;
 
   LWIP_ERROR("netconn_join_leave_group: invalid conn",  (conn != NULL), return ERR_ARG;);
 
-  msg.msg.conn = conn;
-  msg.msg.msg.jl.multiaddr = ip_2_ipX(multiaddr);
-  msg.msg.msg.jl.netif_addr = ip_2_ipX(netif_addr);
-  msg.msg.msg.jl.join_or_leave = join_or_leave;
-  TCPIP_APIMSG(&msg, lwip_netconn_do_join_leave_group, err);
+  API_MSG_VAR_ALLOC(msg);
+#if LWIP_MPU_COMPATIBLE
+  if (multiaddr == NULL) {
+    multiaddr = IP_ADDR_ANY;
+  }
+  if (netif_addr == NULL) {
+    netif_addr = IP_ADDR_ANY;
+  }
+#endif /* LWIP_MPU_COMPATIBLE */
+  API_MSG_VAR_REF(msg).msg.conn = conn;
+  API_MSG_VAR_REF(msg).msg.msg.jl.multiaddr = API_MSG_VAR_REF(ip_2_ipX(multiaddr));
+  API_MSG_VAR_REF(msg).msg.msg.jl.netif_addr = API_MSG_VAR_REF(ip_2_ipX(netif_addr));
+  API_MSG_VAR_REF(msg).msg.msg.jl.join_or_leave = join_or_leave;
+  TCPIP_APIMSG(&API_MSG_VAR_REF(msg), lwip_netconn_do_join_leave_group, err);
+  API_MSG_VAR_FREE(msg);
 
   NETCONN_SET_SAFE_ERR(conn, err);
   return err;
@@ -760,27 +818,42 @@ netconn_join_leave_group(struct netconn *conn,
 err_t
 netconn_gethostbyname(const char *name, ip_addr_t *addr)
 {
-  struct dns_api_msg msg;
-  err_t err;
+  API_VAR_DECLARE(struct dns_api_msg, msg);
+#if !LWIP_MPU_COMPATIBLE
   sys_sem_t sem;
+#endif /* LWIP_MPU_COMPATIBLE */
+  err_t err;
 
   LWIP_ERROR("netconn_gethostbyname: invalid name", (name != NULL), return ERR_ARG;);
   LWIP_ERROR("netconn_gethostbyname: invalid addr", (addr != NULL), return ERR_ARG;);
 
-  err = sys_sem_new(&sem, 0);
-  if (err != ERR_OK) {
-    return err;
+  API_VAR_ALLOC(struct dns_api_msg, MEMP_DNS_API_MSG, msg);
+#if LWIP_MPU_COMPATIBLE
+  if (addr == NULL) {
+    addr = IP_ADDR_ANY;
   }
-
-  msg.name = name;
-  msg.addr = addr;
+#else
   msg.err = &err;
   msg.sem = &sem;
+  API_VAR_REF(msg).addr = API_VAR_REF(addr);
+#endif /* LWIP_MPU_COMPATIBLE */
+  err = sys_sem_new(API_EXPR_REF(API_VAR_REF(msg).sem), 0);
+  if (err != ERR_OK) {
+    API_VAR_FREE(MEMP_DNS_API_MSG, msg);
+    return err;
+  }
+  API_VAR_REF(msg).name = name;
 
-  tcpip_callback(lwip_netconn_do_gethostbyname, &msg);
-  sys_sem_wait(&sem);
-  sys_sem_free(&sem);
+  tcpip_callback(lwip_netconn_do_gethostbyname, &API_VAR_REF(msg));
+  sys_sem_wait(API_EXPR_REF(API_VAR_REF(msg).sem));
+  sys_sem_free(API_EXPR_REF(API_VAR_REF(msg).sem));
 
+#if LWIP_MPU_COMPATIBLE
+  *addr = msg->addr;
+  err = msg->err;
+#endif /* LWIP_MPU_COMPATIBLE */
+
+  API_VAR_FREE(MEMP_DNS_API_MSG, msg);
   return err;
 }
 #endif /* LWIP_DNS*/
diff --git a/src/api/api_msg.c b/src/api/api_msg.c
index 02973389..7f7138ed 100644
--- a/src/api/api_msg.c
+++ b/src/api/api_msg.c
@@ -907,17 +907,17 @@ lwip_netconn_do_bind(struct api_msg_msg *msg)
       switch (NETCONNTYPE_GROUP(msg->conn->type)) {
 #if LWIP_RAW
       case NETCONN_RAW:
-        msg->err = raw_bind(msg->conn->pcb.raw, msg->msg.bc.ipaddr);
+        msg->err = raw_bind(msg->conn->pcb.raw, API_EXPR_REF(msg->msg.bc.ipaddr));
         break;
 #endif /* LWIP_RAW */
 #if LWIP_UDP
       case NETCONN_UDP:
-        msg->err = udp_bind(msg->conn->pcb.udp, msg->msg.bc.ipaddr, msg->msg.bc.port);
+        msg->err = udp_bind(msg->conn->pcb.udp, API_EXPR_REF(msg->msg.bc.ipaddr), msg->msg.bc.port);
         break;
 #endif /* LWIP_UDP */
 #if LWIP_TCP
       case NETCONN_TCP:
-        msg->err = tcp_bind(msg->conn->pcb.tcp, msg->msg.bc.ipaddr, msg->msg.bc.port);
+        msg->err = tcp_bind(msg->conn->pcb.tcp, API_EXPR_REF(msg->msg.bc.ipaddr), msg->msg.bc.port);
         break;
 #endif /* LWIP_TCP */
       default:
@@ -997,12 +997,12 @@ lwip_netconn_do_connect(struct api_msg_msg *msg)
     switch (NETCONNTYPE_GROUP(msg->conn->type)) {
 #if LWIP_RAW
     case NETCONN_RAW:
-      msg->err = raw_connect(msg->conn->pcb.raw, msg->msg.bc.ipaddr);
+      msg->err = raw_connect(msg->conn->pcb.raw, API_EXPR_REF(msg->msg.bc.ipaddr));
       break;
 #endif /* LWIP_RAW */
 #if LWIP_UDP
     case NETCONN_UDP:
-      msg->err = udp_connect(msg->conn->pcb.udp, msg->msg.bc.ipaddr, msg->msg.bc.port);
+      msg->err = udp_connect(msg->conn->pcb.udp, API_EXPR_REF(msg->msg.bc.ipaddr), msg->msg.bc.port);
       break;
 #endif /* LWIP_UDP */
 #if LWIP_TCP
@@ -1012,7 +1012,7 @@ lwip_netconn_do_connect(struct api_msg_msg *msg)
         msg->err = ERR_ISCONN;
       } else {
         setup_tcp(msg->conn);
-        msg->err = tcp_connect(msg->conn->pcb.tcp, msg->msg.bc.ipaddr,
+        msg->err = tcp_connect(msg->conn->pcb.tcp, API_EXPR_REF(msg->msg.bc.ipaddr),
           msg->msg.bc.port, lwip_netconn_do_connected);
         if (msg->err == ERR_OK) {
           u8_t non_blocking = netconn_is_nonblocking(msg->conn);
@@ -1422,10 +1422,10 @@ lwip_netconn_do_getaddr(struct api_msg_msg *msg)
 {
   if (msg->conn->pcb.ip != NULL) {
     if (msg->msg.ad.local) {
-      ipX_addr_copy(PCB_ISIPV6(msg->conn->pcb.ip), *(msg->msg.ad.ipaddr),
+      ipX_addr_copy(PCB_ISIPV6(msg->conn->pcb.ip), API_EXPR_DEREF(msg->msg.ad.ipaddr),
         msg->conn->pcb.ip->local_ip);
     } else {
-      ipX_addr_copy(PCB_ISIPV6(msg->conn->pcb.ip), *(msg->msg.ad.ipaddr),
+      ipX_addr_copy(PCB_ISIPV6(msg->conn->pcb.ip), API_EXPR_DEREF(msg->msg.ad.ipaddr),
         msg->conn->pcb.ip->remote_ip);
     }
     msg->err = ERR_OK;
@@ -1433,7 +1433,7 @@ lwip_netconn_do_getaddr(struct api_msg_msg *msg)
 #if LWIP_RAW
     case NETCONN_RAW:
       if (msg->msg.ad.local) {
-        *(msg->msg.ad.port) = msg->conn->pcb.raw->protocol;
+        API_EXPR_DEREF(msg->msg.ad.port) = msg->conn->pcb.raw->protocol;
       } else {
         /* return an error as connecting is only a helper for upper layers */
         msg->err = ERR_CONN;
@@ -1443,19 +1443,19 @@ lwip_netconn_do_getaddr(struct api_msg_msg *msg)
 #if LWIP_UDP
     case NETCONN_UDP:
       if (msg->msg.ad.local) {
-        *(msg->msg.ad.port) = msg->conn->pcb.udp->local_port;
+        API_EXPR_DEREF(msg->msg.ad.port) = msg->conn->pcb.udp->local_port;
       } else {
         if ((msg->conn->pcb.udp->flags & UDP_FLAGS_CONNECTED) == 0) {
           msg->err = ERR_CONN;
         } else {
-          *(msg->msg.ad.port) = msg->conn->pcb.udp->remote_port;
+          API_EXPR_DEREF(msg->msg.ad.port) = msg->conn->pcb.udp->remote_port;
         }
       }
       break;
 #endif /* LWIP_UDP */
 #if LWIP_TCP
     case NETCONN_TCP:
-      *(msg->msg.ad.port) = (msg->msg.ad.local?msg->conn->pcb.tcp->local_port:msg->conn->pcb.tcp->remote_port);
+      API_EXPR_DEREF(msg->msg.ad.port) = (msg->msg.ad.local?msg->conn->pcb.tcp->local_port:msg->conn->pcb.tcp->remote_port);
       break;
 #endif /* LWIP_TCP */
     default:
@@ -1528,11 +1528,11 @@ lwip_netconn_do_join_leave_group(struct api_msg_msg *msg)
 #if LWIP_IPV6 && LWIP_IPV6_MLD
         if (PCB_ISIPV6(msg->conn->pcb.udp)) {
           if (msg->msg.jl.join_or_leave == NETCONN_JOIN) {
-            msg->err = mld6_joingroup(ipX_2_ip6(msg->msg.jl.netif_addr),
-              ipX_2_ip6(msg->msg.jl.multiaddr));
+            msg->err = mld6_joingroup(ipX_2_ip6(API_EXPR_REF(msg->msg.jl.netif_addr)),
+              ipX_2_ip6(API_EXPR_REF(msg->msg.jl.multiaddr)));
           } else {
-            msg->err = mld6_leavegroup(ipX_2_ip6(msg->msg.jl.netif_addr),
-              ipX_2_ip6(msg->msg.jl.multiaddr));
+            msg->err = mld6_leavegroup(ipX_2_ip6(API_EXPR_REF(msg->msg.jl.netif_addr)),
+              ipX_2_ip6(API_EXPR_REF(msg->msg.jl.multiaddr)));
           }
         }
         else
@@ -1540,11 +1540,11 @@ lwip_netconn_do_join_leave_group(struct api_msg_msg *msg)
         {
 #if LWIP_IGMP
           if (msg->msg.jl.join_or_leave == NETCONN_JOIN) {
-            msg->err = igmp_joingroup(ipX_2_ip(msg->msg.jl.netif_addr),
-              ipX_2_ip(msg->msg.jl.multiaddr));
+            msg->err = igmp_joingroup(ipX_2_ip(API_EXPR_REF(msg->msg.jl.netif_addr)),
+              ipX_2_ip(API_EXPR_REF(msg->msg.jl.multiaddr)));
           } else {
-            msg->err = igmp_leavegroup(ipX_2_ip(msg->msg.jl.netif_addr),
-              ipX_2_ip(msg->msg.jl.multiaddr));
+            msg->err = igmp_leavegroup(ipX_2_ip(API_EXPR_REF(msg->msg.jl.netif_addr)),
+              ipX_2_ip(API_EXPR_REF(msg->msg.jl.multiaddr)));
           }
 #endif /* LWIP_IGMP */
         }
@@ -1578,14 +1578,14 @@ lwip_netconn_do_dns_found(const char *name, ip_addr_t *ipaddr, void *arg)
 
   if (ipaddr == NULL) {
     /* timeout or memory error */
-    *msg->err = ERR_VAL;
+    API_EXPR_DEREF(msg->err) = ERR_VAL;
   } else {
     /* address was resolved */
-    *msg->err = ERR_OK;
-    *msg->addr = *ipaddr;
+    API_EXPR_DEREF(msg->err) = ERR_OK;
+    API_EXPR_DEREF(msg->addr) = *ipaddr;
   }
   /* wake up the application task waiting in netconn_gethostbyname */
-  sys_sem_signal(msg->sem);
+  sys_sem_signal(API_EXPR_REF(msg->sem));
 }
 
 /**
@@ -1599,11 +1599,11 @@ lwip_netconn_do_gethostbyname(void *arg)
 {
   struct dns_api_msg *msg = (struct dns_api_msg*)arg;
 
-  *msg->err = dns_gethostbyname(msg->name, msg->addr, lwip_netconn_do_dns_found, msg);
-  if (*msg->err != ERR_INPROGRESS) {
+  API_EXPR_DEREF(msg->err) = dns_gethostbyname(msg->name, API_EXPR_REF(msg->addr), lwip_netconn_do_dns_found, msg);
+  if (API_EXPR_DEREF(msg->err) != ERR_INPROGRESS) {
     /* on error or immediate success, wake up the application
      * task waiting in netconn_gethostbyname */
-    sys_sem_signal(msg->sem);
+    sys_sem_signal(API_EXPR_REF(msg->sem));
   }
 }
 #endif /* LWIP_DNS */
diff --git a/src/api/netifapi.c b/src/api/netifapi.c
index 81403f82..715d515e 100644
--- a/src/api/netifapi.c
+++ b/src/api/netifapi.c
@@ -37,6 +37,12 @@
 
 #include "lwip/netifapi.h"
 #include "lwip/tcpip.h"
+#include "lwip/memp.h"
+
+#define NETIFAPI_VAR_REF(name)      API_VAR_REF(name)
+#define NETIFAPI_VAR_DECLARE(name)  API_VAR_DECLARE(struct netifapi_msg, name)
+#define NETIFAPI_VAR_ALLOC(name)    API_VAR_ALLOC(struct netifapi_msg, MEMP_NETIFAPI_MSG, name)
+#define NETIFAPI_VAR_FREE(name)     API_VAR_FREE(MEMP_NETIFAPI_MSG, name)
 
 /**
  * Call netif_add() inside the tcpip_thread context.
@@ -45,9 +51,9 @@ static void
 netifapi_do_netif_add(struct netifapi_msg_msg *msg)
 {
   if (!netif_add( msg->netif,
-                  msg->msg.add.ipaddr,
-                  msg->msg.add.netmask,
-                  msg->msg.add.gw,
+                  API_EXPR_REF(msg->msg.add.ipaddr),
+                  API_EXPR_REF(msg->msg.add.netmask),
+                  API_EXPR_REF(msg->msg.add.gw),
                   msg->msg.add.state,
                   msg->msg.add.init,
                   msg->msg.add.input)) {
@@ -65,9 +71,9 @@ static void
 netifapi_do_netif_set_addr(struct netifapi_msg_msg *msg)
 {
   netif_set_addr( msg->netif,
-                  msg->msg.add.ipaddr,
-                  msg->msg.add.netmask,
-                  msg->msg.add.gw);
+                  API_EXPR_REF(msg->msg.add.ipaddr),
+                  API_EXPR_REF(msg->msg.add.netmask),
+                  API_EXPR_REF(msg->msg.add.gw));
   msg->err = ERR_OK;
   TCPIP_NETIFAPI_ACK(msg);
 }
@@ -103,17 +109,33 @@ netifapi_netif_add(struct netif *netif,
                    netif_init_fn init,
                    netif_input_fn input)
 {
-  struct netifapi_msg msg;
-  msg.function = netifapi_do_netif_add;
-  msg.msg.netif = netif;
-  msg.msg.msg.add.ipaddr  = ipaddr;
-  msg.msg.msg.add.netmask = netmask;
-  msg.msg.msg.add.gw      = gw;
-  msg.msg.msg.add.state   = state;
-  msg.msg.msg.add.init    = init;
-  msg.msg.msg.add.input   = input;
-  TCPIP_NETIFAPI(&msg);
-  return msg.msg.err;
+  err_t err;
+  NETIFAPI_VAR_DECLARE(msg);
+  NETIFAPI_VAR_ALLOC(msg);
+#if LWIP_MPU_COMPATIBLE
+  if (ipaddr == NULL) {
+    ipaddr = IP_ADDR_ANY;
+  }
+  if (netmask == NULL) {
+    netmask = IP_ADDR_ANY;
+  }
+  if (gw == NULL) {
+    gw = IP_ADDR_ANY;
+  }
+#endif /* LWIP_MPU_COMPATIBLE */
+  NETIFAPI_VAR_REF(msg).function = netifapi_do_netif_add;
+  NETIFAPI_VAR_REF(msg).msg.netif = netif;
+  NETIFAPI_VAR_REF(msg).msg.msg.add.ipaddr  = NETIFAPI_VAR_REF(ipaddr);
+  NETIFAPI_VAR_REF(msg).msg.msg.add.netmask = NETIFAPI_VAR_REF(netmask);
+  NETIFAPI_VAR_REF(msg).msg.msg.add.gw      = NETIFAPI_VAR_REF(gw);
+  NETIFAPI_VAR_REF(msg).msg.msg.add.state   = state;
+  NETIFAPI_VAR_REF(msg).msg.msg.add.init    = init;
+  NETIFAPI_VAR_REF(msg).msg.msg.add.input   = input;
+  TCPIP_NETIFAPI(&API_VAR_REF(msg));
+
+  err = NETIFAPI_VAR_REF(msg).msg.err;
+  NETIFAPI_VAR_FREE(msg);
+  return err;
 }
 
 /**
@@ -128,14 +150,30 @@ netifapi_netif_set_addr(struct netif *netif,
                         ip_addr_t *netmask,
                         ip_addr_t *gw)
 {
-  struct netifapi_msg msg;
-  msg.function = netifapi_do_netif_set_addr;
-  msg.msg.netif = netif;
-  msg.msg.msg.add.ipaddr  = ipaddr;
-  msg.msg.msg.add.netmask = netmask;
-  msg.msg.msg.add.gw      = gw;
-  TCPIP_NETIFAPI(&msg);
-  return msg.msg.err;
+  err_t err;
+  NETIFAPI_VAR_DECLARE(msg);
+  NETIFAPI_VAR_ALLOC(msg);
+#if LWIP_MPU_COMPATIBLE
+  if (ipaddr == NULL) {
+    ipaddr = IP_ADDR_ANY;
+  }
+  if (netmask == NULL) {
+    netmask = IP_ADDR_ANY;
+  }
+  if (gw == NULL) {
+    gw = IP_ADDR_ANY;
+  }
+#endif /* LWIP_MPU_COMPATIBLE */
+  NETIFAPI_VAR_REF(msg).function = netifapi_do_netif_set_addr;
+  NETIFAPI_VAR_REF(msg).msg.netif = netif;
+  NETIFAPI_VAR_REF(msg).msg.msg.add.ipaddr  = NETIFAPI_VAR_REF(ipaddr);
+  NETIFAPI_VAR_REF(msg).msg.msg.add.netmask = NETIFAPI_VAR_REF(netmask);
+  NETIFAPI_VAR_REF(msg).msg.msg.add.gw      = NETIFAPI_VAR_REF(gw);
+  TCPIP_NETIFAPI(&API_VAR_REF(msg));
+
+  err = NETIFAPI_VAR_REF(msg).msg.err;
+  NETIFAPI_VAR_FREE(msg);
+  return err;
 }
 
 /**
@@ -148,13 +186,19 @@ err_t
 netifapi_netif_common(struct netif *netif, netifapi_void_fn voidfunc,
                        netifapi_errt_fn errtfunc)
 {
-  struct netifapi_msg msg;
-  msg.function = netifapi_do_netif_common;
-  msg.msg.netif = netif;
-  msg.msg.msg.common.voidfunc = voidfunc;
-  msg.msg.msg.common.errtfunc = errtfunc;
-  TCPIP_NETIFAPI(&msg);
-  return msg.msg.err;
+  err_t err;
+  NETIFAPI_VAR_DECLARE(msg);
+  NETIFAPI_VAR_ALLOC(msg);
+
+  NETIFAPI_VAR_REF(msg).function = netifapi_do_netif_common;
+  NETIFAPI_VAR_REF(msg).msg.netif = netif;
+  NETIFAPI_VAR_REF(msg).msg.msg.common.voidfunc = voidfunc;
+  NETIFAPI_VAR_REF(msg).msg.msg.common.errtfunc = errtfunc;
+  TCPIP_NETIFAPI(&API_VAR_REF(msg));
+
+  err = NETIFAPI_VAR_REF(msg).msg.err;
+  NETIFAPI_VAR_FREE(msg);
+  return err;
 }
 
 #endif /* LWIP_NETIF_API */
diff --git a/src/api/sockets.c b/src/api/sockets.c
index 66036712..22905539 100644
--- a/src/api/sockets.c
+++ b/src/api/sockets.c
@@ -51,6 +51,7 @@
 #include "lwip/raw.h"
 #include "lwip/udp.h"
 #include "lwip/tcpip.h"
+#include "lwip/memp.h"
 #include "lwip/pbuf.h"
 #if LWIP_CHECKSUM_ON_COPY
 #include "lwip/inet_chksum.h"
@@ -117,6 +118,20 @@
 #define IS_SOCK_ADDR_ALIGNED(name)      ((((mem_ptr_t)(name)) % 4) == 0)
 
 
+#define LWIP_SETGETSOCKOPT_DATA_VAR_REF(name)     API_VAR_REF(name)
+#define LWIP_SETGETSOCKOPT_DATA_VAR_DECLARE(name) API_VAR_DECLARE(struct lwip_setgetsockopt_data, name)
+#define LWIP_SETGETSOCKOPT_DATA_VAR_FREE(name)    API_VAR_FREE(MEMP_SOCKET_SETGETSOCKOPT_DATA, name)
+#if LWIP_MPU_COMPATIBLE
+#define LWIP_SETGETSOCKOPT_DATA_VAR_ALLOC(name, sock) do { \
+  name = (struct lwip_setgetsockopt_data *)memp_malloc(MEMP_SOCKET_SETGETSOCKOPT_DATA); \
+  if (name == NULL) { \
+    sock_set_errno(sock, ERR_MEM); \
+    return -1; \
+  } }while(0)
+#else /* LWIP_MPU_COMPATIBLE */
+#define LWIP_SETGETSOCKOPT_DATA_VAR_ALLOC(name, sock)
+#endif /* LWIP_MPU_COMPATIBLE */
+
 
 #define NUM_SOCKETS MEMP_NUM_NETCONN
 
@@ -160,28 +175,6 @@ struct lwip_select_cb {
   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;
-};
-
 /** A struct sockaddr replacement that has the same alignment as sockaddr_in/
  *  sockaddr_in6 if instantiated.
  */
@@ -1526,7 +1519,7 @@ 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;
+  LWIP_SETGETSOCKOPT_DATA_VAR_DECLARE(data);
 
   if (!sock) {
     return -1;
@@ -1724,19 +1717,21 @@ lwip_getsockopt(int s, int level, int optname, void *optval, socklen_t *optlen)
   }
 
   /* Now do the actual option processing */
-  data.sock = sock;
+  LWIP_SETGETSOCKOPT_DATA_VAR_ALLOC(data, sock);
+  LWIP_SETGETSOCKOPT_DATA_VAR_REF(data).sock = sock;
 #ifdef LWIP_DEBUG
-  data.s = s;
+  LWIP_SETGETSOCKOPT_DATA_VAR_REF(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);
+  LWIP_SETGETSOCKOPT_DATA_VAR_REF(data).level = level;
+  LWIP_SETGETSOCKOPT_DATA_VAR_REF(data).optname = optname;
+  LWIP_SETGETSOCKOPT_DATA_VAR_REF(data).optval = optval;
+  LWIP_SETGETSOCKOPT_DATA_VAR_REF(data).optlen = optlen;
+  LWIP_SETGETSOCKOPT_DATA_VAR_REF(data).err = err;
+  tcpip_callback(lwip_getsockopt_internal, &LWIP_SETGETSOCKOPT_DATA_VAR_REF(data));
   sys_arch_sem_wait(&sock->conn->op_completed, 0);
   /* maybe lwip_getsockopt_internal has changed err */
-  err = data.err;
+  err = LWIP_SETGETSOCKOPT_DATA_VAR_REF(data).err;
+  LWIP_SETGETSOCKOPT_DATA_VAR_FREE(data);
 
   sock_set_errno(sock, err);
   return err ? -1 : 0;
@@ -1972,7 +1967,7 @@ lwip_setsockopt(int s, int level, int optname, const void *optval, socklen_t opt
 {
   struct lwip_sock *sock = get_socket(s);
   err_t err = ERR_OK;
-  struct lwip_setgetsockopt_data data;
+  LWIP_SETGETSOCKOPT_DATA_VAR_DECLARE(data);
 
   if (!sock) {
     return -1;
@@ -2181,19 +2176,21 @@ lwip_setsockopt(int s, int level, int optname, const void *optval, socklen_t opt
 
 
   /* Now do the actual option processing */
-  data.sock = sock;
+  LWIP_SETGETSOCKOPT_DATA_VAR_ALLOC(data, sock);
+  LWIP_SETGETSOCKOPT_DATA_VAR_REF(data).sock = sock;
 #ifdef LWIP_DEBUG
-  data.s = s;
+  LWIP_SETGETSOCKOPT_DATA_VAR_REF(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);
+  LWIP_SETGETSOCKOPT_DATA_VAR_REF(data).level = level;
+  LWIP_SETGETSOCKOPT_DATA_VAR_REF(data).optname = optname;
+  LWIP_SETGETSOCKOPT_DATA_VAR_REF(data).optval = (void*)optval;
+  LWIP_SETGETSOCKOPT_DATA_VAR_REF(data).optlen = &optlen;
+  LWIP_SETGETSOCKOPT_DATA_VAR_REF(data).err = err;
+  tcpip_callback(lwip_setsockopt_internal, &LWIP_SETGETSOCKOPT_DATA_VAR_REF(data));
   sys_arch_sem_wait(&sock->conn->op_completed, 0);
   /* maybe lwip_setsockopt_internal has changed err */
-  err = data.err;
+  err = LWIP_SETGETSOCKOPT_DATA_VAR_REF(data).err;
+  LWIP_SETGETSOCKOPT_DATA_VAR_FREE(data);
 
   sock_set_errno(sock, err);
   return err ? -1 : 0;
diff --git a/src/api/tcpip.c b/src/api/tcpip.c
index 2c0032c2..31e7c924 100644
--- a/src/api/tcpip.c
+++ b/src/api/tcpip.c
@@ -50,6 +50,11 @@
 #include "netif/etharp.h"
 #include "netif/ppp_oe.h"
 
+#define TCPIP_MSG_VAR_REF(name)     API_VAR_REF(name)
+#define TCPIP_MSG_VAR_DECLARE(name) API_VAR_DECLARE(struct tcpip_msg, name)
+#define TCPIP_MSG_VAR_ALLOC(name)   API_VAR_ALLOC(struct tcpip_msg, MEMP_TCPIP_MSG_API, name)
+#define TCPIP_MSG_VAR_FREE(name)    API_VAR_FREE(MEMP_TCPIP_MSG_API, name)
+
 /* global variables */
 static tcpip_init_done_fn tcpip_init_done;
 static void *tcpip_init_done_arg;
@@ -311,17 +316,19 @@ tcpip_untimeout(sys_timeout_handler h, void *arg)
 err_t
 tcpip_apimsg(struct api_msg *apimsg)
 {
-  struct tcpip_msg msg;
+  TCPIP_MSG_VAR_DECLARE(msg);
 #ifdef LWIP_DEBUG
   /* catch functions that don't set err */
   apimsg->msg.err = ERR_VAL;
 #endif
   
   if (sys_mbox_valid(&mbox)) {
-    msg.type = TCPIP_MSG_API;
-    msg.msg.apimsg = apimsg;
-    sys_mbox_post(&mbox, &msg);
+    TCPIP_MSG_VAR_ALLOC(msg);
+    TCPIP_MSG_VAR_REF(msg).type = TCPIP_MSG_API;
+    TCPIP_MSG_VAR_REF(msg).msg.apimsg = apimsg;
+    sys_mbox_post(&mbox, &TCPIP_MSG_VAR_REF(msg));
     sys_arch_sem_wait(&apimsg->msg.conn->op_completed, 0);
+    TCPIP_MSG_VAR_FREE(msg);
     return apimsg->msg.err;
   }
   return ERR_VAL;
@@ -341,20 +348,24 @@ tcpip_apimsg(struct api_msg *apimsg)
 err_t
 tcpip_netifapi(struct netifapi_msg* netifapimsg)
 {
-  struct tcpip_msg msg;
-  
+  TCPIP_MSG_VAR_DECLARE(msg);
+
   if (sys_mbox_valid(&mbox)) {
-    err_t err = sys_sem_new(&netifapimsg->msg.sem, 0);
+    err_t err;
+    TCPIP_MSG_VAR_ALLOC(msg);
+
+    err = sys_sem_new(&netifapimsg->msg.sem, 0);
     if (err != ERR_OK) {
       netifapimsg->msg.err = err;
       return err;
     }
     
-    msg.type = TCPIP_MSG_NETIFAPI;
-    msg.msg.netifapimsg = netifapimsg;
-    sys_mbox_post(&mbox, &msg);
+    TCPIP_MSG_VAR_REF(msg).type = TCPIP_MSG_NETIFAPI;
+    TCPIP_MSG_VAR_REF(msg).msg.netifapimsg = netifapimsg;
+    sys_mbox_post(&mbox, &TCPIP_MSG_VAR_REF(msg));
     sys_sem_wait(&netifapimsg->msg.sem);
     sys_sem_free(&netifapimsg->msg.sem);
+    TCPIP_MSG_VAR_FREE(msg);
     return netifapimsg->msg.err;
   }
   return ERR_VAL;
diff --git a/src/core/init.c b/src/core/init.c
index 52d7baa0..3095bd38 100644
--- a/src/core/init.c
+++ b/src/core/init.c
@@ -232,9 +232,6 @@
 #ifdef MEMP_NUM_TCPIP_MSG
   #error "MEMP_NUM_TCPIP_MSG option is deprecated. Remove it from your lwipopts.h."
 #endif
-#ifdef MEMP_NUM_API_MSG
-  #error "MEMP_NUM_API_MSG option is deprecated. Remove it from your lwipopts.h."
-#endif
 #ifdef TCP_REXMIT_DEBUG
   #error "TCP_REXMIT_DEBUG option is deprecated. Remove it from your lwipopts.h."
 #endif
diff --git a/src/core/memp.c b/src/core/memp.c
index cc967981..992b2307 100644
--- a/src/core/memp.c
+++ b/src/core/memp.c
@@ -48,6 +48,7 @@
 #include "lwip/igmp.h"
 #include "lwip/api.h"
 #include "lwip/api_msg.h"
+#include "lwip/sockets.h"
 #include "lwip/tcpip.h"
 #include "lwip/sys.h"
 #include "lwip/timers.h"
diff --git a/src/include/lwip/api_msg.h b/src/include/lwip/api_msg.h
index 8268036a..95614b7a 100644
--- a/src/include/lwip/api_msg.h
+++ b/src/include/lwip/api_msg.h
@@ -48,6 +48,12 @@
 extern "C" {
 #endif
 
+#if LWIP_MPU_COMPATIBLE
+#define API_MSG_M_DEF(m)  m
+#else /* LWIP_MPU_COMPATIBLE */
+#define API_MSG_M_DEF(m)  *m
+#endif /* LWIP_MPU_COMPATIBLE */
+
 /* For the netconn API, these values are use as a bitmask! */
 #define NETCONN_SHUT_RD   1
 #define NETCONN_SHUT_WR   2
@@ -75,13 +81,13 @@ struct api_msg_msg {
     } n;
     /** used for lwip_netconn_do_bind and lwip_netconn_do_connect */
     struct {
-      ip_addr_t *ipaddr;
+      ip_addr_t API_MSG_M_DEF(ipaddr);
       u16_t port;
     } bc;
     /** used for lwip_netconn_do_getaddr */
     struct {
-      ipX_addr_t *ipaddr;
-      u16_t *port;
+      ipX_addr_t API_MSG_M_DEF(ipaddr);
+      u16_t API_MSG_M_DEF(port);
       u8_t local;
     } ad;
     /** used for lwip_netconn_do_write */
@@ -104,8 +110,8 @@ struct api_msg_msg {
 #if LWIP_IGMP || (LWIP_IPV6 && LWIP_IPV6_MLD)
     /** used for lwip_netconn_do_join_leave_group */
     struct {
-      ipX_addr_t *multiaddr;
-      ipX_addr_t *netif_addr;
+      ipX_addr_t API_MSG_M_DEF(multiaddr);
+      ipX_addr_t API_MSG_M_DEF(netif_addr);
       enum netconn_igmp join_or_leave;
     } jl;
 #endif /* LWIP_IGMP || (LWIP_IPV6 && LWIP_IPV6_MLD) */
@@ -136,12 +142,12 @@ struct dns_api_msg {
   /** Hostname to query or dotted IP address string */
   const char *name;
   /** Rhe resolved address is stored here */
-  ip_addr_t *addr;
+  ip_addr_t API_MSG_M_DEF(addr);
   /** This semaphore is posted when the name is resolved, the application thread
       should wait on it. */
-  sys_sem_t *sem;
+  sys_sem_t API_MSG_M_DEF(sem);
   /** Errors are given back here */
-  err_t *err;
+  err_t API_MSG_M_DEF(err);
 };
 #endif /* LWIP_DNS */
 
diff --git a/src/include/lwip/memp_std.h b/src/include/lwip/memp_std.h
index 8e1c99c4..18afe7c6 100644
--- a/src/include/lwip/memp_std.h
+++ b/src/include/lwip/memp_std.h
@@ -58,6 +58,18 @@ LWIP_MEMPOOL(NETCONN,        MEMP_NUM_NETCONN,         sizeof(struct netconn),
 
 #if NO_SYS==0
 LWIP_MEMPOOL(TCPIP_MSG_API,  MEMP_NUM_TCPIP_MSG_API,   sizeof(struct tcpip_msg),      "TCPIP_MSG_API")
+#if LWIP_MPU_COMPATIBLE
+LWIP_MEMPOOL(API_MSG,        MEMP_NUM_API_MSG,         sizeof(struct api_msg),        "API_MSG")
+#if LWIP_DNS
+LWIP_MEMPOOL(DNS_API_MSG,    MEMP_NUM_DNS_API_MSG,     sizeof(struct dns_api_msg),    "DNS_API_MSG")
+#endif
+#if LWIP_SOCKET
+LWIP_MEMPOOL(SOCKET_SETGETSOCKOPT_DATA, MEMP_NUM_SOCKET_SETGETSOCKOPT_DATA, sizeof(struct lwip_setgetsockopt_data), "SOCKET_SETGETSOCKOPT_DATA")
+#endif
+#if LWIP_NETIF_API
+LWIP_MEMPOOL(NETIFAPI_MSG,   MEMP_NUM_NETIFAPI_MSG,    sizeof(struct netifapi_msg),   "NETIFAPI_MSG")
+#endif
+#endif /* LWIP_MPU_COMPATIBLE */
 #if !LWIP_TCPIP_CORE_LOCKING_INPUT
 LWIP_MEMPOOL(TCPIP_MSG_INPKT,MEMP_NUM_TCPIP_MSG_INPKT, sizeof(struct tcpip_msg),      "TCPIP_MSG_INPKT")
 #endif /* !LWIP_TCPIP_CORE_LOCKING_INPUT */
diff --git a/src/include/lwip/netifapi.h b/src/include/lwip/netifapi.h
index 648151b6..37a6743f 100644
--- a/src/include/lwip/netifapi.h
+++ b/src/include/lwip/netifapi.h
@@ -41,6 +41,12 @@
 extern "C" {
 #endif
 
+#if LWIP_MPU_COMPATIBLE
+#define NETIFAPI_IPADDR_DEF(m)  m
+#else /* LWIP_MPU_COMPATIBLE */
+#define NETIFAPI_IPADDR_DEF(m)  *m
+#endif /* LWIP_MPU_COMPATIBLE */
+
 typedef void (*netifapi_void_fn)(struct netif *netif);
 typedef err_t (*netifapi_errt_fn)(struct netif *netif);
 
@@ -52,9 +58,9 @@ struct netifapi_msg_msg {
   struct netif *netif;
   union {
     struct {
-      ip_addr_t *ipaddr;
-      ip_addr_t *netmask;
-      ip_addr_t *gw;
+      ip_addr_t NETIFAPI_IPADDR_DEF(ipaddr);
+      ip_addr_t NETIFAPI_IPADDR_DEF(netmask);
+      ip_addr_t NETIFAPI_IPADDR_DEF(gw);
       void *state;
       netif_init_fn init;
       netif_input_fn input;
diff --git a/src/include/lwip/opt.h b/src/include/lwip/opt.h
index 82946d0f..2becda85 100644
--- a/src/include/lwip/opt.h
+++ b/src/include/lwip/opt.h
@@ -92,6 +92,16 @@
 #define SMEMCPY(dst,src,len)            memcpy(dst,src,len)
 #endif
 
+/**
+ * LWIP_MPU_COMPATIBLE: enables special memory management mechanism
+ * which makes lwip able to work on MPU (Memory Protection Unit) system
+ * by not passing stack-pointers to other threads
+ * (this decreases performance)
+ */
+#ifndef LWIP_MPU_COMPATIBLE
+#define LWIP_MPU_COMPATIBLE             0
+#endif
+
 /*
    ------------------------------------
    ---------- Memory options ----------
@@ -414,6 +424,33 @@
 #define PBUF_POOL_SIZE                  16
 #endif
 
+/** MEMP_NUM_API_MSG: the number of concurrently active calls to various
+ * socket, netconn, and tcpip functions
+ */
+#ifndef MEMP_NUM_API_MSG
+#define MEMP_NUM_API_MSG                MEMP_NUM_TCPIP_MSG_API
+#endif
+
+/** MEMP_NUM_DNS_API_MSG: the number of concurrently active calls to netconn_gethostbyname
+ */
+#ifndef MEMP_NUM_DNS_API_MSG
+#define MEMP_NUM_DNS_API_MSG            MEMP_NUM_TCPIP_MSG_API
+#endif
+
+/** MEMP_NUM_SOCKET_SETGETSOCKOPT_DATA: the number of concurrently active calls
+ * to getsockopt/setsockopt
+ */
+#ifndef MEMP_NUM_SOCKET_SETGETSOCKOPT_DATA
+#define MEMP_NUM_SOCKET_SETGETSOCKOPT_DATA MEMP_NUM_TCPIP_MSG_API
+#endif
+
+/** MEMP_NUM_NETIFAPI_MSG: the number of concurrently active calls to the
+ * netifapi functions
+ */
+#ifndef MEMP_NUM_NETIFAPI_MSG
+#define MEMP_NUM_NETIFAPI_MSG           MEMP_NUM_TCPIP_MSG_API
+#endif
+
 /*
    ---------------------------------
    ---------- ARP options ----------
diff --git a/src/include/lwip/sockets.h b/src/include/lwip/sockets.h
index 74cd252c..ba4ca7b6 100644
--- a/src/include/lwip/sockets.h
+++ b/src/include/lwip/sockets.h
@@ -41,6 +41,7 @@
 #include <stddef.h> /* for size_t */
 
 #include "lwip/ip_addr.h"
+#include "lwip/err.h"
 #include "lwip/inet.h"
 #include "lwip/inet6.h"
 
@@ -105,6 +106,30 @@ struct sockaddr_storage {
 typedef u32_t socklen_t;
 #endif
 
+struct lwip_sock;
+
+/** 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;
+};
+
 /* Socket protocol types (TCP/UDP/RAW) */
 #define SOCK_STREAM     1
 #define SOCK_DGRAM      2
diff --git a/src/include/lwip/tcpip.h b/src/include/lwip/tcpip.h
index 04567f2c..5b71cf1b 100644
--- a/src/include/lwip/tcpip.h
+++ b/src/include/lwip/tcpip.h
@@ -87,6 +87,35 @@ extern sys_mutex_t lock_tcpip_core;
 #define TCPIP_NETIFAPI_ACK(m) sys_sem_signal(&m->sem)
 #endif /* LWIP_TCPIP_CORE_LOCKING */
 
+
+#if LWIP_MPU_COMPATIBLE
+#define API_VAR_REF(name)               (*(name))
+#define API_VAR_DECLARE(type, name)     type * name
+#define API_VAR_ALLOC(type, pool, name) do { \
+                                          name = (type *)memp_malloc(pool); \
+                                          if (name == NULL) { \
+                                            return ERR_MEM; \
+                                          } \
+                                        } while(0)
+#define API_VAR_ALLOC_DONTFAIL(type, pool, name) do { \
+                                          name = (type *)memp_malloc(pool); \
+                                          LWIP_ASSERT("pool empty", name != NULL); \
+                                        } while(0)
+#define API_VAR_FREE(pool, name)        memp_free(pool, name)
+#define API_EXPR_REF(expr)              &(expr)
+#define API_EXPR_DEREF(expr)            expr
+#else /* LWIP_MPU_COMPATIBLE */
+#define API_VAR_REF(name)               name
+#define API_VAR_DECLARE(type, name)     type name
+#define API_VAR_ALLOC(type, pool, name)
+#define API_VAR_ALLOC_DONTFAIL(type, pool, name)
+#define API_VAR_FREE(pool, name)
+#define API_EXPR_REF(expr)              expr
+#define API_EXPR_DEREF(expr)            *(expr)
+#endif /* LWIP_MPU_COMPATIBLE */
+
+
+
 /** Function prototype for the init_done function passed to tcpip_init */
 typedef void (*tcpip_init_done_fn)(void *arg);
 /** Function prototype for functions passed to tcpip_callback() */