Advertise DNS-Server status as up conditionally to discovery-server.

Conditions are based on config read completely from IfMap Server
and connection to named is UP.

Added checks for pid recirculation by associating to named process.
(diffs from Hari Prasad Killi)

Change-Id: I24510c77ac1fa00dfcc48b4ac087e7cc164bc579
Closes-Bug:1477742
Closes-Bug:1489610

src/dns/bind/named_config.cc

@@ -491,6 +491,28 @@ bool BindStatus::SetTrigger() {
     return false;
 }
 
+// Check if a given pid belongs to contrail-named
+bool BindStatus::IsBindPid(uint32_t pid) {
+    bool ret = false;
+    std::stringstream str;
+    str << "/proc/" << pid << "/cmdline";
+
+    ifstream ifile(str.str().c_str());
+    if (ifile.good()) {
+        std::string cmdline;
+        cmdline.assign((istreambuf_iterator<char>(ifile)),
+                        istreambuf_iterator<char>());
+        istringstream cmdstream(cmdline);
+        if (cmdstream.str().find("/usr/bin/contrail-named") !=
+            std::string::npos) {
+           ret = true;
+        }
+    }
+
+    ifile.close();
+    return ret;
+}
+
 bool BindStatus::CheckBindStatus() {
     uint32_t new_pid = -1;
     NamedConfig *ncfg = NamedConfig::GetNamedConfigObject();
@@ -502,11 +524,16 @@ bool BindStatus::CheckBindStatus() {
         pid_file.close();
     }
 
-    if (new_pid != named_pid_) {
-        named_pid_ = new_pid;
-        if (new_pid == (uint32_t) -1) {
+    if (new_pid == (uint32_t) -1) {
+        handler_(Down);
+    } else if (!IsBindPid(new_pid)) {
+        if (named_pid_ != (uint32_t) -1) {
+            named_pid_ = -1;
             handler_(Down);
-        } else {
+        }
+    } else {
+        if (named_pid_ != new_pid) {
+            named_pid_ = new_pid;
             handler_(Up);
         }
     }

src/dns/bind/named_config.h

@@ -29,6 +29,7 @@ class BindStatus {
 private:
     friend class DnsBindTest;
 
+    bool IsBindPid(uint32_t pid);
     bool CheckBindStatus();
 
     uint32_t named_pid_;

src/dns/main.cc

@@ -55,6 +55,25 @@ bool DnsInfoLogger() {
     return true;
 }
 
+bool DnsServerReEvaluatePublishCb(IFMapServer *ifmap_server,
+                                  std::string &message) {
+
+    IFMapManager *ifmap_manager = ifmap_server->get_ifmap_manager();
+    if (ifmap_manager && !ifmap_manager->GetEndOfRibComputed()) {
+        message = "IFMap Server End-Of-RIB not computed";
+        return false;
+    }
+
+    DnsManager *dns_manager = Dns::GetDnsManager();
+    if (dns_manager && !dns_manager->IsBindStatusUp()) {
+        message = "Connection to named DOWN";
+        return false;
+    }
+
+    message = "OK";
+    return true;
+}
+
 static string FileRead(const string &filename) {
     ifstream file(filename.c_str());
     string content((istreambuf_iterator<char>(file)),
@@ -222,7 +241,8 @@ int main(int argc, char *argv[]) {
                       "</port></" << sname << ">";
             std::string pub_msg;
             pub_msg = pub_ss.str();
-            ds_client->Publish(sname, pub_msg);
+            ds_client->Publish(sname, pub_msg,
+                boost::bind(&DnsServerReEvaluatePublishCb, &ifmap_server, _1));
         }
 
         //subscribe to collector service if not configured

src/dns/mgr/dns_mgr.h

@@ -72,6 +72,7 @@ class DnsManager {
                        DnsConfigManager::EventType event);
     void ProcessAgentUpdate(BindUtil::Operation event, const std::string &name,
                             const std::string &vdns_name, const DnsItem &item);
+    bool IsBindStatusUp() { return bind_status_.IsUp(); }
 
 private:
     friend class DnsBindTest;