add check for full window with SSHD and improve nonblocking connect w…

apps/wolfsshd/wolfsshd.c

@@ -704,6 +704,7 @@ static int SHELL_Subsystem(WOLFSSHD_CONNECTION* conn, WOLFSSH* ssh,
     byte shellBuffer[EXAMPLE_BUFFER_SZ];
     byte channelBuffer[EXAMPLE_BUFFER_SZ];
     char* forcedCmd;
+    int   windowFull = 0;
 
     forcedCmd = wolfSSHD_ConfigGetForcedCmd(usrConf);
 
@@ -876,7 +877,7 @@ static int SHELL_Subsystem(WOLFSSHD_CONNECTION* conn, WOLFSSH* ssh,
             pending = 1; /* found some pending SSH data */
         }
 
-        if (pending || FD_ISSET(sshFd, &readFds)) {
+        if (windowFull || pending || FD_ISSET(sshFd, &readFds)) {
             word32 lastChannel = 0;
 
             /* The following tries to read from the first channel inside
@@ -910,6 +911,19 @@ static int SHELL_Subsystem(WOLFSSHD_CONNECTION* conn, WOLFSSH* ssh,
             }
         }
 
+        /* if the window was previously full, try resending the data */
+        if (windowFull) {
+            cnt_w = wolfSSH_ChannelIdSend(ssh, shellChannelId,
+                    shellBuffer, cnt_r);
+            if (cnt_w == WS_WINDOW_FULL) {
+                windowFull = 1;
+                continue;
+            }
+            else {
+                windowFull = 0;
+            }
+        }
+
         if (FD_ISSET(childFd, &readFds)) {
             cnt_r = (int)read(childFd, shellBuffer, sizeof shellBuffer);
             /* This read will return 0 on EOF */
@@ -923,7 +937,11 @@ static int SHELL_Subsystem(WOLFSSHD_CONNECTION* conn, WOLFSSH* ssh,
                 if (cnt_r > 0) {
                     cnt_w = wolfSSH_ChannelIdSend(ssh, shellChannelId,
                             shellBuffer, cnt_r);
-                    if (cnt_w < 0)
+                    if (cnt_w == WS_WINDOW_FULL) {
+                        windowFull = 1;
+                        continue;
+                    }
+                    else if (cnt_w < 0)
                         break;
                 }
             }

examples/client/client.c

@@ -148,10 +148,17 @@ static int NonBlockSSH_connect(WOLFSSH* ssh)
             printf("... client would write block\n");
 
         select_ret = tcp_select(sockfd, 1);
-        if (select_ret == WS_SELECT_RECV_READY ||
+
+        /* Continue in want write cases even if did not select on socket
+         * because there could be pending data to be written. Added continue
+         * on want write for test cases where a forced want read was introduced
+         * and the socket will not be receiving more data. */
+        if (error == WS_WANT_WRITE || error == WS_WANT_READ ||
+            select_ret == WS_SELECT_RECV_READY ||
             select_ret == WS_SELECT_ERROR_READY)
         {
             ret = wolfSSH_connect(ssh);
+            error = wolfSSH_get_error(ssh);
         }
         else if (select_ret == WS_SELECT_TIMEOUT)
             error = WS_WANT_READ;

src/internal.c

@@ -2264,8 +2264,14 @@ static int GetInputData(WOLFSSH* ssh, word32 size)
 
     /* Take into account the data already in the buffer. Update size
      * for what is missing in the request. */
-    word32 haveDataSz = ssh->inputBuffer.length - ssh->inputBuffer.idx;
+    word32 haveDataSz;
 
+    /* reset want read state before attempting to read */
+    if (ssh->error == WS_WANT_READ) {
+        ssh->error = 0;
+    }
+
+    haveDataSz = ssh->inputBuffer.length - ssh->inputBuffer.idx;
     if (haveDataSz >= size) {
         WLOG(WS_LOG_INFO, "GID: have enough already, return early");
         return WS_SUCCESS;