--- /tmp/ppp.c	Wed Aug  3 10:05:54 2005
+++ /tmp/ppp.c8130Dow	Wed Aug  3 10:05:54 2005
@@ -133,6 +131,8 @@
  * PPP interface control block.
  */
 typedef struct PPPControl_s {
+    sys_thread_t thread;
+    sys_sem_t open_sem;
     char openFlag;                      /* True when in use. */
     char oldFrame;                      /* Old framing character for fd. */
     sio_fd_t fd;                    /* File device ID of port. */
@@ -180,10 +180,11 @@
 /***********************************/
 /*** LOCAL FUNCTION DECLARATIONS ***/
 /***********************************/
-static void pppMain(void *pd);
-static void pppDrop(PPPControl *pc);
+static void pppDrop(PPPControl *);
+static void pppMain(void *);
 static void pppInProc(int pd, u_char *s, int l);
 
+static void ppp_thread(void *);
 
 /******************************/
 /*** PUBLIC DATA STRUCTURES ***/
@@ -299,14 +300,18 @@
 
     for (i = 0; i < NUM_PPP; i++) {
         pppControl[i].openFlag = 0;
+        pppControl[i].open_sem = sys_sem_new(0);
+        LWIP_ASSERT("pppControl[i].open_sem", pppControl[i].open_sem != SYS_SEM_NULL);
 
-		subnetMask = htonl(0xffffff00);
+        subnetMask = htonl(0xffffff00);
     
         /*
          * Initialize to the standard option set.
          */
         for (j = 0; (protp = ppp_protocols[j]) != NULL; ++j)
             (*protp->init)(i);
+
+        pppControl[i].thread = sys_thread_new(ppp_thread, (void *)i, PPP_THREAD_PRIO);
     }
 
 #if LINK_STATS
@@ -387,17 +390,15 @@
     int pd;
 
     /* Find a free PPP session descriptor. Critical region? */
-    for (pd = 0; pd < NUM_PPP && pppControl[pd].openFlag != 0; pd++);
+    for (pd = 0; pd < NUM_PPP; pd++) {
+        if (!pppControl[pd].openFlag)
+            break;
+    }
+
     if (pd >= NUM_PPP)
         pd = PPPERR_OPEN;
-    else
-        pppControl[pd].openFlag = !0;
-
-    /* Launch a deamon thread. */
-    if (pd >= 0) {
-
-        pppControl[pd].openFlag = 1;
-
+    else {
+        /* release daemon thread. */
         lcp_init(pd);
         pc = &pppControl[pd];
         pc->fd = fd;
@@ -428,7 +429,8 @@
 	pc->linkStatusCB = linkStatusCB;
 	pc->linkStatusCtx = linkStatusCtx;
 
-	sys_thread_new(pppMain, (void*)pd, PPP_THREAD_PRIO);
+        sys_sem_signal(pc->open_sem);
+
 	if(!linkStatusCB) {
 		while(pd >= 0 && !pc->if_up) {
 			sys_msleep(500);
@@ -454,9 +456,9 @@
     int st = 0;
 
     /* Disconnect */
-    pc->kill_link = !0;
+    pc->kill_link = 1;
     pppMainWakeup(pd);
-    
+
     if(!pc->linkStatusCB) {
 	    while(st >= 0 && lcp_phase[pd] != PHASE_DEAD) {
 		    sys_msleep(500);
@@ -992,7 +994,6 @@
 	return ERR_OK;
 }
 
-
 /*
  * sifup - Config the interface up and enable IP packets to pass.
  */
@@ -1196,6 +1197,29 @@
 /**********************************/
 /*** LOCAL FUNCTION DEFINITIONS ***/
 /**********************************/
+static void
+ppp_thread(void *arg)
+{
+    int pd = (int)arg;
+    PPPControl *pc = &pppControl[pd];
+
+    for (;;) {
+        // wait for open
+        sys_sem_wait(pc->open_sem);
+
+        PPPDEBUG((LOG_INFO, "ppp_thread[%d]: open request\n", pd));
+
+        pppControl[pd].openFlag = 1;
+
+        pppMain(arg);
+
+        PPPDEBUG((LOG_INFO, "ppp_thread[%d]: closed\n", pd));
+
+        pppControl[pd].openFlag = 0;
+    }
+}
+
+
 /* The main PPP process function.  This implements the state machine according
  * to section 4 of RFC 1661: The Point-To-Point Protocol. */
 static void pppMain(void *arg)
@@ -1247,8 +1269,6 @@
 	PPPDEBUG((LOG_DEBUG, "pppMain: unit %d: linkStatusCB=%lx errCode=%d\n", pd, pc->linkStatusCB, pc->errCode));
     if(pc->linkStatusCB)
 	    pc->linkStatusCB(pc->linkStatusCtx, pc->errCode ? pc->errCode : PPPERR_PROTOCOL, NULL);
-
-    pc->openFlag = 0;
 }
 
 static struct pbuf *pppSingleBuf(struct pbuf *p)