From aac014618c8af75262e5483fcc09dddbeb11bcc3 Mon Sep 17 00:00:00 2001
From: Markus Zolliker <markus.zolliker@psi.ch>
Date: Tue, 3 Jul 2018 11:14:18 +0200
Subject: [PATCH] - merged "offline" and "disconnected" stati

---
 ascon.c  | 70 ++++++++++++++++++++++++++++++++++++++++++--------------
 devser.c |  4 ++--
 2 files changed, 55 insertions(+), 19 deletions(-)

diff --git a/ascon.c b/ascon.c
index dcd23272..09440e99 100644
--- a/ascon.c
+++ b/ascon.c
@@ -17,13 +17,52 @@
 static double lastClose = 0; /* time of last close operation */
 static AsconProtocol *protocols = NULL;
 
+long parse_dotted_adr(const char *dottedadr) {
+  int ip[4];
+  int i;
+  
+  if (sscanf(dottedadr, "%d.%d.%d.%d", ip, ip+1, ip+2, ip+3) != 4) return 0;
+  for (i=0; i<3; i++) {
+    if (ip[i] < 0 || ip[i] > 255) return 0;
+  }
+  return ip[0] + (ip[1] << 8) + (ip[2] << 16) + (ip[3] << 24);
+}
+
+long ns_lookup(char *hostname) {
+  FILE *fil;
+  char line[256];
+  long ipadr;
+
+  ipadr = parse_dotted_adr(hostname);
+  if (ipadr) return ipadr;
+  snprintf(line, sizeof line, "timeout 1 nslookup %s", hostname);
+  fil = popen(line, "r");
+  if (fil == NULL) {
+    return 0;
+  }
+  while (fgets(line, sizeof(line), fil) != NULL) {
+    if (strncmp(line, "Address: ", 9) == 0) {
+      ipadr = parse_dotted_adr(line+9);
+      if (ipadr) {
+        fclose(fil);
+        return ipadr;
+      }
+    }
+  }
+  fclose(fil);
+  return 0;
+}
+
 /*
-     CreateSocketAdress stolen from Tcl. Thanks to John Ousterhout
+     Based on CreateSocketAdress from John Ousterhout
+     Use ns_lookup instead of gethostbyname, as the latter uses a cache, which
+     is not sufficient in some cases (switching off and on a LakeShore 336 does
+     acquire a new address, but the value in the cache is not updates)
 */
 
-static int CreateSocketAdress(struct sockaddr_in *sockaddrPtr,  /* Socket address */
-                              char *host,       /* Host.  NULL implies INADDR_ANY */
-                              int port)
+static int MakeSocketAdress(struct sockaddr_in *sockaddrPtr,  /* Socket address */
+                            char *host,       /* Host.  NULL implies INADDR_ANY */
+                            int port)
 {                               /* Port number */
   struct hostent *hostent;      /* Host database entry */
   struct in_addr addr;          /* For 64/32 bit madness */
@@ -34,15 +73,12 @@ static int CreateSocketAdress(struct sockaddr_in *sockaddrPtr,  /* Socket addres
   if (host == NULL) {
     addr.s_addr = INADDR_ANY;
   } else {
-    hostent = gethostbyname(host);
-    if (hostent != NULL) {
+    addr.s_addr = ns_lookup(host);
+    if (addr.s_addr == 0) { /* try gethostbyname only if ns_lookup failed */
+      hostent = gethostbyname(host);
+      if (hostent == NULL) return 0; /* error */
       memcpy((char *) &addr,
              (char *) hostent->h_addr_list[0], (size_t) hostent->h_length);
-    } else {
-      addr.s_addr = inet_addr(host);
-      if (addr.s_addr == (unsigned int) -1) {
-        return 0;               /* error */
-      }
     }
   }
   /*
@@ -68,7 +104,7 @@ void AsconError(Ascon *a, char *msg, int errorno)
     "read done",
     "idle",
     "failed",
-    "timeout"
+    "no response"
   };
   char *state;
   char num[8];
@@ -108,7 +144,8 @@ static void AsconConnect(Ascon * a)
   char *colon;
   int port;
   int oldopts;
-  
+  char ipaddress[16];
+
   /* wait 0.5 sec before connecting again after a close
      2 reasons for that:
      - it seems that connecting immediately to a closed port fails.
@@ -135,7 +172,7 @@ static void AsconConnect(Ascon * a)
   colon = strchr(a->hostport, ':');
   if (colon == NULL) {
     if (strcmp(a->hostport, "unconnected") == 0) {
-      AsconError(a, "offline", 0);
+      AsconError(a, "disconnected", 0);
     } else {
       AsconError(a, "expected 'host:port' or 'unconnected'", 0);
     }
@@ -147,7 +184,7 @@ static void AsconConnect(Ascon * a)
     return;
   }
   *colon = '\0';
-  ret = CreateSocketAdress(&adr, a->hostport, port);
+  ret = MakeSocketAdress(&adr, a->hostport, port);
   *colon = ':';
   if (ret == 0) {
     a->ip = 0;
@@ -157,8 +194,7 @@ static void AsconConnect(Ascon * a)
   a->ip = adr.sin_addr.s_addr;
   oldopts = fcntl(a->fd, F_GETFL, 0);
   fcntl(a->fd, F_SETFL, oldopts | O_NONBLOCK);
-  ret =
-      connect(a->fd, (struct sockaddr *) &adr, sizeof(struct sockaddr_in));
+  ret = connect(a->fd, (struct sockaddr *) &adr, sizeof(struct sockaddr_in));
   if (ret < 0) {
     switch (errno) {
     case EINPROGRESS:
diff --git a/devser.c b/devser.c
index e1d58946..05d9101c 100644
--- a/devser.c
+++ b/devser.c
@@ -254,7 +254,7 @@ int DevQueueTask(void *ds)
         LogResponse(devser,0);
       }
     } else if (devser->status == AsconOffline) {
-      replyData = "ASCERR: offline";
+      replyData = "ASCERR: disconnected";
     } else {
       return 1;
     }
@@ -602,7 +602,7 @@ char *DevStatus(DevSer *devser) {
   if (strncmp(str, "ASCERR: ", 8) == 0) {
     str += 8;
   }
-  pos = strchr(str, '(');
+  pos = strstr(str, " (");
   if (pos != 0) {
     snprintf(buf, sizeof buf, "%s", str);
     buf[pos-str] = 0;