diff --git a/src/api/sockets.c b/src/api/sockets.c
index b7632489..786a294e 100644
--- a/src/api/sockets.c
+++ b/src/api/sockets.c
@@ -44,6 +44,8 @@
  *
  */
 
+//#include <errno.h>
+
 #include "lwip/opt.h"
 
 #if LWIP_SOCKET /* don't build if not configured for use in lwipopts.h */
diff --git a/src/api/tcpip.c b/src/api/tcpip.c
index 07b2f984..f10136e2 100644
--- a/src/api/tcpip.c
+++ b/src/api/tcpip.c
@@ -150,6 +150,11 @@ tcpip_thread(void *arg)
       msg->msg.cb.function(msg->msg.cb.ctx);
       break;
 
+    case TCPIP_MSG_SHUTDOWN:
+      LWIP_DEBUGF(TCPIP_DEBUG, ("tcpip_thread: SHUTDOWN %p\n", (void *)msg));
+      sys_sem_signal(msg->msg.api_call.sem);
+      return;
+
     default:
       LWIP_DEBUGF(TCPIP_DEBUG, ("tcpip_thread: invalid message: %d\n", msg->type));
       LWIP_ASSERT("tcpip_thread: invalid message", 0);
@@ -158,6 +163,49 @@ tcpip_thread(void *arg)
   }
 }
 
+err_t
+tcpip_shutdown(void)
+{
+  //struct tcpip_msg msg;
+  sys_sem_t sem;
+
+  /* If there is no tcpip mailbox, leave */
+  if (mbox == SYS_MBOX_NULL)
+      return ERR_OK;
+
+  /* Create semaphore for message */
+  sys_sem_new(&sem, 0);
+  LWIP_ASSERT("tcpip_terminate: failed to create semaphore\n",
+      sem != SYS_SEM_NULL);
+  if (sem == SYS_SEM_NULL) {
+    return ERR_MEM;
+  }
+
+  /* TODO: do we need to stop the timers? if so, how? */
+
+  struct tcpip_msg *msg;
+  LWIP_ASSERT("Invalid mbox", sys_mbox_valid_val(mbox));
+  msg = (struct tcpip_msg *)memp_malloc(MEMP_TCPIP_MSG_INPKT);
+
+  /* Tell tcpip thread to exit, and wait */
+  msg->msg.api_call.sem = &sem;
+  msg->type = TCPIP_MSG_SHUTDOWN;
+
+  if (sys_mbox_trypost(&mbox, msg) != ERR_OK) {
+    memp_free(MEMP_TCPIP_MSG_INPKT, msg);
+    return ERR_MEM;
+  }
+
+  sys_arch_sem_wait(&sem, 0);
+
+  /* clean up tcpip thread resources */
+
+  //sys_mbox_free(&mbox);
+  sys_sem_free(&sem);
+  mbox = SYS_MBOX_NULL;
+  return ERR_OK;
+}
+
 /**
  * Pass a received packet to tcpip_thread for input processing
  *
diff --git a/src/core/ipv6/ip6.c b/src/core/ipv6/ip6.c
index f14e3342..facd3b21 100644
--- a/src/core/ipv6/ip6.c
+++ b/src/core/ipv6/ip6.c
@@ -264,6 +264,17 @@ ip6_select_source_address(struct netif *netif, const ip6_addr_t *dest)
     }
   }
 
+  /* Choose a ZeroTier adhoc with matching prefix. */
+  if (ip6_addr_is_zt_adhoc(dest)) {
+    for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
+      if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
+          ip6_addr_is_zt_adhoc(netif_ip6_addr(netif, i)) &&
+          ip6_addr_6plane_cmp(dest, netif_ip6_addr(netif, i))) {
+        return netif_ip_addr6(netif, i);
+      }
+    }
+  }
+
   /* Last resort: see if arbitrary prefix matches. */
   for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
     if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
diff --git a/src/core/ipv6/nd6.c b/src/core/ipv6/nd6.c
index 0b367181..2a5b77d4 100644
--- a/src/core/ipv6/nd6.c
+++ b/src/core/ipv6/nd6.c
@@ -1361,8 +1361,13 @@ nd6_is_prefix_in_netif(const ip6_addr_t *ip6addr, struct netif *netif)
   }
   /* Check to see if address prefix matches a (manually?) configured address. */
   for (i = 0; i < LWIP_IPV6_NUM_ADDRESSES; i++) {
-    if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) &&
-        ip6_addr_netcmp(ip6addr, netif_ip6_addr(netif, i))) {
+    int prefix_match = 0;
+    if (ip6_addr_is_zt_6plane(ip6addr) || ip6_addr_is_zt_adhoc(ip6addr)) {
+      prefix_match = ip6_addr_6plane_cmp(ip6addr, netif_ip6_addr(netif, i));
+    } else {
+      prefix_match = ip6_addr_netcmp(ip6addr, netif_ip6_addr(netif, i));
+    }
+    if (ip6_addr_isvalid(netif_ip6_addr_state(netif, i)) && prefix_match) {
       return 1;
     }
   }
diff --git a/src/core/timeouts.c b/src/core/timeouts.c
index 8bf209a5..cf4e556a 100644
--- a/src/core/timeouts.c
+++ b/src/core/timeouts.c
@@ -186,6 +186,19 @@ void sys_timeouts_init(void)
   timeouts_last_time = sys_now();
 }
 
+/** Remove all timeouts */
+void sys_timeouts_free(void)
+{
+  size_t i;
+  for (i = (LWIP_TCP ? 1 : 0); i < LWIP_ARRAYSIZE(lwip_cyclic_timers); i++) {
+    /* we have to cast via size_t to get rid of const warning
+      (this is OK as cyclic_timer() casts back to const* */
+    sys_untimeout(cyclic_timer, LWIP_CONST_CAST(void*, &lwip_cyclic_timers[i]));
+  }
+  /* Initialise timestamp for sys_check_timeouts */
+  timeouts_last_time = sys_now();
+}
+
 /**
  * Create a one-shot timer (aka timeout). Timeouts are processed in the
  * following cases:
diff --git a/src/include/lwip/errno.h b/src/include/lwip/errno.h
index 641cffb0..cec43f7f 100644
--- a/src/include/lwip/errno.h
+++ b/src/include/lwip/errno.h
@@ -174,7 +174,11 @@ extern "C" {
 #define  EMEDIUMTYPE    124  /* Wrong medium type */
 
 #ifndef errno
-extern int errno;
+#if defined(__linux__) && !defined(__ANDROID__)
+	#include <errno.h>
+#else
+	extern int errno;
+#endif
 #endif
 
 #else /* LWIP_PROVIDE_ERRNO */
diff --git a/src/include/lwip/ip6_addr.h b/src/include/lwip/ip6_addr.h
index ee381aeb..b879f212 100644
--- a/src/include/lwip/ip6_addr.h
+++ b/src/include/lwip/ip6_addr.h
@@ -133,6 +133,14 @@ typedef struct ip6_addr ip6_addr_t;
 #define ip6_addr_netcmp(addr1, addr2) (((addr1)->addr[0] == (addr2)->addr[0]) && \
                                        ((addr1)->addr[1] == (addr2)->addr[1]))
 
+#define ip6_addr_is_zt_6plane(addr1) (((addr1)->addr[0] & PP_HTONL(0xffffffffUL)) == PP_HTONL(0xfc937e7fUL) && \
+                                        ((addr1)->addr[1] & PP_HTONL(0xff000000UL)) == PP_HTONL(0x72000000UL))
+
+#define ip6_addr_is_zt_adhoc(addr1) (((addr1)->addr[0] & PP_HTONL(0xffff0000UL)) == PP_HTONL(0xfce90000UL))
+
+#define ip6_addr_6plane_cmp(addr1, addr2) (((addr1)->addr[0] == (addr2)->addr[0]) && \
+                                    ((addr1)->addr[1] & PP_HTONL(0xff000000UL)) == ((addr2)->addr[1] & PP_HTONL(0xff000000UL)))
+
 #define ip6_addr_cmp(addr1, addr2) (((addr1)->addr[0] == (addr2)->addr[0]) && \
                                     ((addr1)->addr[1] == (addr2)->addr[1]) && \
                                     ((addr1)->addr[2] == (addr2)->addr[2]) && \
diff --git a/src/include/lwip/priv/tcpip_priv.h b/src/include/lwip/priv/tcpip_priv.h
index 630efb14..41fb3e60 100644
--- a/src/include/lwip/priv/tcpip_priv.h
+++ b/src/include/lwip/priv/tcpip_priv.h
@@ -117,7 +117,8 @@ enum tcpip_msg_type {
   TCPIP_MSG_UNTIMEOUT,
 #endif /* LWIP_TCPIP_TIMEOUT && LWIP_TIMERS */
   TCPIP_MSG_CALLBACK,
-  TCPIP_MSG_CALLBACK_STATIC
+  TCPIP_MSG_CALLBACK_STATIC,
+  TCPIP_MSG_SHUTDOWN
 };
 
 struct tcpip_msg {
diff --git a/src/include/lwip/sockets.h b/src/include/lwip/sockets.h
index 2522056d..1af0c989 100644
--- a/src/include/lwip/sockets.h
+++ b/src/include/lwip/sockets.h
@@ -104,7 +104,7 @@ struct sockaddr_storage {
 
 /* If your port already typedef's socklen_t, define SOCKLEN_T_DEFINED
    to prevent this code from redefining it. */
-#if !defined(socklen_t) && !defined(SOCKLEN_T_DEFINED)
+#if !defined(socklen_t) && !defined(SOCKLEN_T_DEFINED) && !defined(__ANDROID__)
 typedef u32_t socklen_t;
 #endif
 
diff --git a/src/include/lwip/tcpip.h b/src/include/lwip/tcpip.h
index f2f6b469..60d3578b 100644
--- a/src/include/lwip/tcpip.h
+++ b/src/include/lwip/tcpip.h
@@ -73,6 +73,7 @@ typedef void (*tcpip_callback_fn)(void *ctx);
 struct tcpip_callback_msg;
 
 void   tcpip_init(tcpip_init_done_fn tcpip_init_done, void *arg);
+err_t  tcpip_shutdown();
 
 err_t  tcpip_inpkt(struct pbuf *p, struct netif *inp, netif_input_fn input_fn);
 err_t  tcpip_input(struct pbuf *p, struct netif *inp);
diff --git a/src/include/lwip/timeouts.h b/src/include/lwip/timeouts.h
index c9b93aa0..74385dd4 100644
--- a/src/include/lwip/timeouts.h
+++ b/src/include/lwip/timeouts.h
@@ -94,6 +94,7 @@ struct sys_timeo {
 };
 
 void sys_timeouts_init(void);
+void sys_timeouts_free(void);
 
 #if LWIP_DEBUG_TIMERNAMES
 void sys_timeout_debug(u32_t msecs, sys_timeout_handler handler, void *arg, const char* handler_name);