detect lack of physical network connection

svn path=/trunk/boinc/; revision=9404

checkin_notes

@@ -1487,3 +1487,20 @@ Rom    6 Feb 2006
     client/
         client_state.h
         main.C
+
+David  6 Feb 2005
+    - Core client: when we switched to Curl, we lost the code
+        that sets gstate.want_network_flag when name resolution fails.
+        I restored this to the Curl code.
+
+    - The above is a kludge for detecting lack of physical connection.
+        But name resolution can fail for reasons other than lack of
+        physical connection; e.g. hostname might be bad.
+        So if get name resolution failure,
+        try to contact a reference web site,
+        and only if that also fails set want_network_flag.
+
+    client/
+        acct_setup.C
+        client_state.C,h
+        net_xfer_curl.C

client/acct_setup.C

@@ -188,6 +188,15 @@ int LOOKUP_WEBSITE_OP::do_rpc(string& url) {
 
 void LOOKUP_WEBSITE_OP::handle_reply(int http_op_retval) {
     error_num = http_op_retval;
+
+    // if we couldn't contact a reference web site,
+    // we can assume there's a problem that requires user attention
+    // (usually no physical network connection).
+    // Set a flag that will signal the Manager to that effect
+    //
+    if (error_num) {
+        gstate.want_network_flag = true;
+    }
 }
 
 int GET_CURRENT_VERSION_OP::do_rpc() {

client/client_state.C

@@ -1393,15 +1393,15 @@ int CLIENT_STATE::detach_project(PROJECT* project) {
     return 0;
 }
 
-// Return true if the core client wants a network connection.
-// Don't return false if we've actually been using the network
-// in the last 10 seconds (so that polling mechanisms
-// have a change to trigger)
+// Return true if the core client wants a network connection,
+// or if we've been using the network in the last 10 seconds
+// (so that polling mechanisms have a change to trigger)
 //
 bool CLIENT_STATE::want_network() {
     static double last_true_return=0;
 
     if (http_ops->nops()) goto return_true;
+        // if we're using network, return true
     if (network_suspended) goto return_false;
     if (want_network_flag) goto return_true;
     if (active_tasks.want_network()) goto return_true;

client/client_state.h

@@ -241,7 +241,19 @@ public:
     int report_result_error(RESULT&, const char *format, ...);
     int reset_project(PROJECT*);
     bool want_network_flag;
+        // client wants to do network comm and no physical connection exists.
+        // Initially false; set whenever a Curl operation
+        // returns CURLE_COULDNT_RESOLVE_HOST;
+        // cleared whenever a Curl operation returns anything else
+        // TODO: is this the best way to do this?
+        // won't it set this flag when user enters URL with
+        // non-existent URL, e.g.?
+        //
     bool have_sporadic_connection;
+        // we have a network connection, but it's likely to go away soon,
+        // so do as much network comm as possible
+        // (e.g. report completed results)
+        //
     bool want_network();
     void network_available();
     bool no_gui_rpc;

client/net_xfer_curl.C

@@ -66,12 +66,14 @@ using std::vector;
 //
 #define NET_XFER_TIMEOUT    600
 
-CURLM* g_curlMulti = NULL;  // global curl for this module, can handle http & https
+CURLM* g_curlMulti = NULL;
 
 // the file descriptor sets need to be global so libcurl has access always
+//
 fd_set read_fds, write_fds, error_fds;
 
-// call these once at the start of the program and once at the end (init & cleanup of course)
+// call these once at the start of the program and once at the end
+//
 int curl_init() {
     curl_global_init(CURL_GLOBAL_ALL);
     g_curlMulti = curl_multi_init();
@@ -95,11 +97,11 @@ void NET_XFER::reset() {
     is_connected = false;
     want_download = false;
     want_upload = false;
-    do_file_io = true;  // CMC Note: should I default to true, i.e. this does all i/o?
+    do_file_io = true;
     io_done = false;
     fileIn = NULL;
     fileOut = NULL;
-    io_ready = true;  // don't allow higher levels to do i/o?
+    io_ready = true;
     error = 0;
     file_read_buf_offset = 0;
     file_read_buf_len = 0;
@@ -125,7 +127,8 @@ NET_XFER::~NET_XFER() {
 }
 
 void NET_XFER::close_socket() {
-    // CMC: this just cleans up the curlEasy, and "spoofs" the old close_socket
+    // this cleans up the curlEasy, and "spoofs" the old close_socket
+    //
     if (pcurlList) {
         curl_slist_free_all(pcurlList);
         pcurlList = NULL;
@@ -195,9 +198,6 @@ NET_XFER_SET::NET_XFER_SET() {
     bytes_down = 0;
 }
 
-// Connect to a server,
-// and if successful insert the NET_XFER object into the set
-//
 int NET_XFER_SET::insert(NET_XFER* nxp) {
     net_xfers.push_back(nxp);
     return 0;
@@ -223,7 +223,9 @@ int NET_XFER_SET::remove(NET_XFER* nxp) {
 
 void NET_XFER_SET::get_fdset(FDSET_GROUP& fg) {
     CURLMcode curlMErr;
-    curlMErr = curl_multi_fdset(g_curlMulti, &fg.read_fds, &fg.write_fds, &fg.exc_fds, &fg.max_fd);
+    curlMErr = curl_multi_fdset(
+        g_curlMulti, &fg.read_fds, &fg.write_fds, &fg.exc_fds, &fg.max_fd
+    );
     //printf("curl msfd %d %d\n", curlMErr, fg.max_fd);
 }
 
@@ -265,6 +267,7 @@ void NET_XFER_SET::got_select(FDSET_GROUP&, double timeout) {
     }
 
     // read messages from curl that may have come in from the above loop
+    //
     while ((pcurlMsg = curl_multi_info_read(g_curlMulti, &iNumMsg))) {
         // if we have a msg, then somebody finished
         // can check also with pcurlMsg->msg == CURLMSG_DONE
@@ -304,9 +307,12 @@ void NET_XFER_SET::got_select(FDSET_GROUP&, double timeout) {
         }
 
         // the op is done if curl_multi_msg_read gave us a msg for this http_op
+        //
         nxf->http_op_state = HTTP_STATE_DONE;
 
-        // added a more useful error string (just pass the curl string up for now)
+        // added a more useful error string
+        // (just pass the curl string up for now)
+        //
         nxf->CurlResult = pcurlMsg->data.result;
         safe_strcpy(nxf->strCurlResult, curl_easy_strerror(nxf->CurlResult));
 
@@ -334,6 +340,16 @@ void NET_XFER_SET::got_select(FDSET_GROUP&, double timeout) {
                 nxf->http_op_retval = nxf->response;
             }
         } else {
+            // If we couldn't resolve hostname,
+            // it could be because there's no physical network connection.
+            // Find out for sure by trying to contact google
+            //
+            if (nxf->CurlResult == CURLE_COULDNT_RESOLVE_HOST) {
+                std::string url = "http://www.google.com";
+                gstate.lookup_website_op.do_rpc(url);
+            } else {
+                gstate.want_network_flag = false;
+            }
             msg_printf(0, MSG_ERROR, "HTTP error: %s", nxf->strCurlResult);
             nxf->http_op_retval = ERR_HTTP_ERROR;
         }
@@ -347,11 +363,12 @@ void NET_XFER_SET::got_select(FDSET_GROUP&, double timeout) {
             file_size(nxf->outfile, dSize);
             nxf->fileOut = boinc_fopen(nxf->outfile, "rb");
             if (!nxf->fileOut) { // ack, can't open back up!
-                nxf->response = 1; // flag as a bad response for a possible retry later
+                nxf->response = 1;
+                    // flag as a bad response for a possible retry later
             } else {
                 fseek(nxf->fileOut, 0, SEEK_SET);
                 // CMC Note: req1 is a pointer to "header" which is 4096
-                memset(nxf->req1, 0x00, 4096);
+                memset(nxf->req1, 0, 4096);
                 fread(nxf->req1, 1, (size_t) dSize, nxf->fileOut); 
             }
         }